11 - הכנס השנתי ה העמותה הישראלית למדעי הימים 2112 מאי 22

‫הכנס השנתי ה‪11-‬‬
‫העמותה הישראלית למדעי הימים‬
‫‪ 22‬מאי ‪2112‬‬
‫‪00:00-00:80‬‬
‫‪00:80-00:00‬‬
‫אודיטוריום ריץ'‬
‫‪00:00-50:00‬‬
‫מושבים מקבילים‬
‫התכנסות‪ ,‬רישום‪ ,‬קפה‬
‫דברי פתיחה‪ :‬דר' אורן לוי‪ ,‬נשיא העמותה הישראלית למדעי הימים‬
‫פרופ' צבי דובינסקי – הצגת גיליון "ים"‬
‫דרור צוראל – הצגת מפת תוכניות הניטור הימי של המשרד להגנת הסביבה‬
‫חדר ‪B13‬‬
‫אודיטוריום ריץ' (קומה ‪2‬‬
‫(קומת מרתף)‬
‫במעלית‪ 5/‬במדרגות)‬
‫גיאוכימיה‬
‫וגיאולוגיה ימית‬
‫יו"ר‪ :‬ברק חירות‬
‫חקר ימים ואגמים‬
‫ביולוגיה של צורבניים‬
‫יו"ר‪ :‬דרור צוראל‬
‫המשרד להגנת הסביבה‬
‫‪50:00-55:00‬‬
‫‪55:00-50:00‬‬
‫מושבים מקבילים‬
‫חדר ‪020‬‬
‫(קומה ‪)0‬‬
‫סדנת מארג‬
‫"מדד בריאות הים"‬
‫הפסקת קפה‬
‫הסביבה הימית בעולם‬
‫משתנה‬
‫יו"ר‪ :‬רועי הולצמן‬
‫‪ ,IUI‬אונ' ת"א‬
‫מיקרואורגניזמים בים‬
‫יו"ר‪ :‬תמר זוהרי‬
‫חקר ימים ואגמים‬
‫‪00:11-00:11‬‬
‫סדנת מארג‬
‫"מדד בריאות הים"‬
‫‪00:11-00:11‬‬
‫סדנת אוקיינוגרפיה פיזיקלית ‪-‬‬
‫דיפוזיה כפולה ואי יציבות‬
‫יו"ר‪ :‬חזי גילדור‬
‫האונ' העברית‬
‫‪50:00-50:00‬‬
‫ארוחת צהריים‬
‫‪50:00-58:00‬‬
‫אודיטוריום ריץ'‬
‫אסיפת עמותה כללית ‪ +‬בחירות לנציג חדש לוועד העמותה‬
‫‪58:00-50:00‬‬
‫אודיטוריום ריץ'‬
‫‪50:00-53:00‬‬
‫מושבים מקבילים‬
‫‪Guest lecture: Prof. Iain Couzin, Princeton university‬‬
‫‪Sensory networks and distributed cognition in schooling fish‬‬
‫הסביבה הבנטית והים העמוק‬
‫יו"ר‪ :‬אהובה אלמוגי‪-‬לבין‬
‫המכון הגיאולוגי‬
‫אוקיאנוגרפיה פיזיקאלית‬
‫יו"ר‪ :‬יוסי אשכנזי‬
‫אונ' בן גוריון‬
‫שולחן עגול ‪ :‬שיטות גנומיות ומטא‪-‬‬
‫גנומיות בחקר הים‬
‫‪53:00-50:00‬‬
‫מושב פוסטרים (בליווי בירה‪ ,‬קפה ונשנושים )‬
‫‪50:00-50:50‬‬
‫רחבת כניסה‬
‫חלוקת פרסים להרצאה המצטיינת ולפוסטרים המצטיינים‬
‫אירוע השקה לאתר זווית‪ -‬האגודה הישראלית לאקולוגיה ומדעי הסביבה‬
‫‪50:50-50:00‬‬
‫אודיטוריום ריץ'‬
‫‪03:01-01:01‬‬
‫(‪Guest lecture: Dr. David Gruber (NY University/NY Times/National Geographic‬‬
‫‪Deep Diving Expeditions - Uncovering the biodiversity of luminescent & fluorescent‬‬
‫‪creatures and applications in medical research‬‬
‫קוקטייל חגיגי על רקע השקיעה‬
‫שלום וברכה למשתתפי הכנס‪,‬‬
‫הכנס השנתי ה‪ 11-‬של העמותה הישראלית למדעי הימים מתקיים השנה במרכז פרס‬
‫לשלום‪ ,‬יפו‪.‬‬
‫לפניכם התוכנית של הכנס השנתי ה‪ 11-‬של העמותה הישראלית למדעי הימים לשנת‬
‫‪ .4112‬בהמשכה מקבץ התקצירים של ההרצאות והכרזות המוצגות בכנס (ע"פ סדר הא'‪-‬‬
‫ב')‪.‬‬
‫הכנס השנה נערך בשיתוף עם האגודה הישראלית לאקולוגיה ומדעי הסביבה שבמסגרתו‬
‫תחשף העמותה ומשתתפי הכנס לגורמי תקשורת‪.‬‬
‫השנה משתתפים בכנס גם משתתפים מחו"ל‪ .‬כמו כן‪ ,‬גם השנה המעורבות של סטודנטים‬
‫בכנס הינה גדולה וע"פ הנרשמים עד כה כ‪ 01%-‬מהנרשמים הינם סטודנטים לתארים‬
‫מתקדמים‪.‬‬
‫כמו בכל שנה אנו מעודדים את השתתפות הסטודנטים ומחלקים פרסים כספיים להרצאה‬
‫הטובה ביותר ולשלושת הכרזות הטובות ביותר שיוצגו בכנס ויבחרו על ידי צוות שופטים‬
‫מחברי העמותה‪.‬‬
‫הכנס יכלול השנה ‪ 24‬הרצאות ו‪ 54-‬כרזות‪.‬‬
‫השנה‪ ,‬מס' רב של מוסדות תמכו בכנס בניהם המשרד להגנת הסביבה‪ ,‬המכון‬
‫הבינאוניברסיטאי למדעי הים באילת‪ ,‬המארג‪ ,‬המכון לחקר ימים ואגמים לישראל‪ ,‬בית‬
‫הספר למדעי הים באוניברסיטת חיפה‪ ,‬אוניברסיטת בר‪-‬אילן‪ ,‬האוניברסיטה העברית‬
‫והמרכז לחקר ים תיכון ועל כך תודתנו נתונה‪.‬‬
‫אנו מאחלים לכם כנס מעניין ומקווים לראותכם בשנה הבאה‪.‬‬
‫וועד חברי העמותה (לפי סדר א'‪-‬ב')‪:‬‬
‫עדה אלאמרו (נציגת סטודנטים)‬
‫תמר זוהרי (מבקרת)‬
‫תמר לוטן‬
‫אורן לוי (נשיא)‬
‫עמית לרנר (גזבר)‬
‫נגה סטמבלר‬
‫ניר שטרן (נציג סטודנטים)‬
‫אלדו שמש (מבקר)‬
‫יעלה שקד‬
‫דניאל שר‬
OCEAN WARMING EFFECTS ON ZOOXANTHELLATE CORALS
Hofit Admony, David Iluz and Zvy Dubinsky
Bar ilan university [email protected], [email protected], [email protected]
The concentration of atmospheric pCO2 has increase since the industrial revolution. This increase
caused an elevation of Earth's average surface temperature, as well as an acidification of the
oceans. The effects of elevated temperature on the scleractinian coral population cause bleaching
events whereby the corals lose their algal symbionts which provide most of the metabolic energy
they need. The Mediterranean scleractinian coral Balanophyllia europaea is a zooxanthellate
solitary coral common on subtidal rocky substrates. In an aquarium experimental system we
examined the effect of elevated temperature without or combined with acidification of the sea
water (pH 7.8) during a long term exposure on the photosynthetic efficiency of B. europaea.
Photosynthesis, respiration, chlorophyll and quantum yield were measured at 17, 20, 23, 26,
29°C . The temperature was elevated gradually (1°C every 20 days), with a constant temperature
aquarium as a control and an additional acidic aquarium (pH=7.8), also exposed to the same
protocol of temperature increase. Photosynthetic efficiency was measured by a unique method
developed in our lab, based on photoacoustics, and with a variable fluorescence PAM device.
Both methods showed an optimum temperature at 23°C, a decrease in photosynthetic efficiency
at 26°C and a stronger decrease at 29°C. Photosynthetic efficiency compared with the control
showed significant changes whereas the controls showed some increase in some cases, probably
as a result of acclimation of the corals with time. The acidic aquarium compared with the nonacidic show a lower photosynthetic efficiency at the higher temperatures, suggesting a synergy
between temperature and acidification. Comparing photosynthetic efficiency to the other
parameters as respiration, chlorophyll concentration and algae count can show a more detailed
picture of the stressors affecting scleractinian corals in our time of climate change.
IS EASTERN MEDITERRANEAN HEAT CONTENT A GOOD PREDICTOR FOR
PRECIPITATION IN ISRAEL?
Yael Amitai and Hezi Gildor
The Fredy and Nadine Herrmann Institute of Earth Sciences, The Hebrew University Edmond J. Safra
Campus, Givat Ram Jerusalem, 91904 [email protected]
The synoptic system responsible for most of the rainfall over Israel is the Cyprus Low which
carries cold air eastward over warm Eastern Mediterranean (EM) waters and gain moisture. As
the amount of evaporation depends on the air-sea temperature difference and the amount of
heat stored in the upper ocean, Tzvetkov and Assaf (1982) suggested that the EM upper layer
heat content in the summer/autumn is a good predictor of the amount of precipitation in the
following winter over Israel. We revisit this hypothesis by calculating EM upper layer heat content
during the last 20 years (1992/3-2012/3) based on remote sensing sea surface temperature
(SST) and sea level anomaly (SLA). The method we use to calculate the EM heat content is based
on a reduced gravity model that combines SLA, SST, Med-Atlas (2002) climatological data and
hydrographic casts from PERSEUS (Policy-oriented marine Environmental Research for the
Southern European Seas). We then perform correlation analysis between the EM heat content
and daily rain measurements from the Israel meteorological service in 8, 6 and 7 stations located
in Haifa, Tel Aviv and Jerusalem, respectively. Tzvetkov and Assaf (1982) found a correlation of
0.55 between autumn heat content and the following winter rain during 11 years between 19521969. In our analysis of the years 2002-2012 we have also found a correlation of 0.55 using a
completely different method. However, when analyze ten more years, from 1992 until 2002, the
correlation drops to 0.3. Since the reliability of the correlation increases with the amount of
measurements available, we argue that the hypothesis we revisit is not supported by the data
collected during the last two decades.
SULFUR AND OXYGEN ISOTOPE TRACING OF SULFATE DRIVEN ANAEROBIC
METHANE OXIDATION IN ESTUARINE SEDIMENTS
Gilad Antler1,2, Alexandra V. Turchyn1, Barak Herut3 Alicia Davies1, Michal Adler2, Victoria
Rennie1 and Orit Sivan2
1
Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK. [email protected]
Department of Geological and Environmental Sciences, Ben Gurion University, Beer Sheva 84105,Israel
3
Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
2
Methane is an important greenhouse gas whose production is driven mainly by the microbially
mediated methanogenesis. This methane is almost entirely consumed by anaerobic methane
oxidation (AOM) coupled bacterial sulfate reduction (BSR). The details of this coupling between
AOM and BSR remain enigmatic.
This study seeks to use the sulfur and oxygen isotope
composition of sulfate (34SSO4 and 18OSO4 respectively) consumed through AOM to further our
understanding of the mechanism of this critical microbially-mediated process. We focus on highly
stratified estuaries in the coastal area of Israel (the Yarkon and the Qishon). At these sites,
sulfate is rapidly consumed and methane concentrations subsequently increase, suggest intensive
production of methane deeper within the sediment. Although the pore fluid sulfate and dissolved
inorganic carbon (DIC) concentration profiles change over a similar range with respect to depth,
the sulfur and oxygen isotopes in the pore fluid sulfate and the carbon isotopes in the pore fluid
DIC are fundamentally different. This pore fluid isotope geochemistry indicates that the microbial
mechanism of sulfate reduction differs between the studied sites. We suggest that in the Yarqon
estuary, sulfate is consumed entirely through AOM, whereas in the Qishon, both AOM and
bacterial sulfate reduction through organic matter oxidation coexist.
These results have
implications for understanding the microbial mechanisms behind sulfate-driven AOM. We compile
data from marine and marginal marine environments that supports our conclusion that the
intracellular pathways of sulfate reduction varies among environments with sulfate-driven AOM.
The data can be used to elucidate new pathways in the cycling of methane and sulfate, and the
findings are applicable to the broader marine environment.
DOUBLE DIFFUSION INSTANILITIES
Yosef Ashkenazy1, Avi Gozolchiani1 and Hezi Gildor2
1
Department of Solar Energy and Environmental Physics, The Jacob Blaustein Institutes for Desert
Research, Ben-Gurion University of the Negev, Sede Boqer campus, 84990
2
The Fredy and Nadine Herrmann Institute of Earth Sciences, The Hebrew University Edmond J. Safra
Campus, Givat Ram Jerusalem, 91904
Stratified fluid may become unstable due to differences between the heat and salinity diffusion
properties. Such instability is usually referred to as “double diffusion”. We will first summarize the
observations regarding double diffusion processes and highlight the important of these processes
in ocean dynamics. We will then review the conditions that lead to double diffusion and the ways
to characterize and quantify them. We will also list the open questions related to double diffusion.
INSTABILITIES AND EDDIES OF A SNOWBALL OCEAN
Yosef Ashkenazy1 and Eli Tziperman2
1
Department of Solar Energy and Environmental Physics, The Blaustein Institutes for Desert Research, BenGurion University of the Negev, Midreshet Ben-Gurion, 84990, Israel.
2
Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, Massachusetts 02138, USA
An ocean covered by (~1 km) thick ice, motivated by Snowball Earth conditions and driven by a
very weak geothermal heat flux, is shown to be characterized by an energetic turbulent eddy
field. There are two opposite-sign zonal jets on the two sides of the equator, and changing sign
with depth. In addition, multiple barotropic eddy-driven jets appear off the equator. We discuss
the instability processes underlying the eddies and jets, and the eddy-mean flow interactions
generating and sustaining them. We also estimate eddy-parametrized viscosity and diffusion
coefficients based on the eddy resolving simulations.
BATHYMETRIC ZONATION OF THE ISRAELI SHALLOW SHELF BASED ON
RECENT BENTHIC FORAMINIFERA AND MULTIVARIATE ANALYSES:
IMPLICATIONS FOR PALEOBATHYMETRICAL RECONSTRUCTION
Simona Avnaim-Katav1, Yvonne Milker2, Orit Hyams-Kaphzan3 and Ahuva Almogi-Labin3
1
Department of Maritime Civilizations and the Leon Recanati Institute for Maritime Studies (RIMS), University
of Haifa, Mount Carmel, Haifa 31905, Israel [email protected]
2
University of Hamburg, Department of Geosciences, Institute for Geology, Bundesstrasse 55, 20146
Hamburg, Germany [email protected]
2
Geological Survey of Israel, 30 Malkhe Yisrael, Jerusalem 95501, Israel [email protected] / [email protected]
Shallow-water benthic foraminifera from surface sediments of siliciclastic carbonate-poor to
carbonate-rich substrates were studied in the Mediterranean continental shelf of Israel in order to
determine the role of substrate and water depth on their distribution. Sediments for this study
were collected from 74 stations between Akhziv (north) and Ashqelon (south) and from 3 to 100
m water depth. Multivariate statistical analyses resulted in the identification of three distinct
foraminiferal assemblages and their association with various environmental parameters. The
foraminiferal assemblages exhibit a clear bathymetric zonation directly related to substrate type
which corresponds to water depth. A distinct faunal change has been found at approximately 40
m water depth coinciding with the shift from shallow-water sandy to deeper water fine-grained
sediments. The sandy belt, part of the Nile littoral cell, parallels the Israeli coast and extends up
to Haifa Bay. The fine-grained silty-clayey sediment belt extends westward to the sand belt along
the entire Israeli shelf. Ammonia parkinsoniana, Ammonia sp. 1, Buccella granulata, Nubeculina
divaricata and Adelosina sp. 1 (in decreasing order of abundance) predominating shallow-water
depths, are positively correlated with sand fraction and negatively correlated with water depth.
Whereas, a large number of species occurring at deeper than 40 m water depths, such as
Asterigerinata mamilla, Discorbinella rhodiensis, Reussella spinulosa, Triloculina marioni and
Valvulineria bradyana demonstrate a positive correlation with water depth. Beyond the Nile littoral
cell and partly in its distal part where carbonate content is relatively high, Amphistegina lessonii,
Peneroplis
pertusus,
Pseudoschlumbergerina
ovata,
Pseudoschlumbergerina
sp.
1
and
Quinqueloculina ungeriana dominate the rocky and coarse-sands substrates, exhibiting a
significant positive correlation with higher carbonate content. The distinct bathymetric zonation
characterizing the benthic foraminifera in the eastern Mediterranean shallow shelf may prove to
be useful in fossil records for quantitative paleobathymetric estimations.
PHYSIOLOGICAL CHARACTERIZATION OF LYTIC BACTERIA-ALGAL
INTERACTIONS DURING COCCOLITHOPHORE BLOOMS
Noa Barak, Miguel J. Frada and Assaf Vardi
Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
[email protected], [email protected], [email protected]
Coccolithophores are an abundant group of phytoplankton in the oceans. They have great
ecological and biogeochemical relevance, playing a central role in global carbon and sulfur cycles.
Emiliania huxleyi is the most abundant coccolithophore and forms massive annual blooms that
cover vast oceanic areas. A common observation during demise of E. huxleyi blooms is the
concurrent growth of bacteria populations. Nonetheless, there is no clear understanding of the
cellular mechanisms mediating E. huxleyi-bacteria interaction and the ecological significance of
this fundamental biotic interaction. Recently, we collected copepods during natural E. huxleyi
blooms in the North Atlantic. Exposure of E. huxleyi cultures to copepod-homogenate lead to E.
huxleyi growth suppression along with the development of a distinctive bacterial population
(referred as VICE). Incubation with VICE showed lytic effect against E. huxleyi strains in culture.
This effect was abolished upon application of antibiotics, strongly linking bacteria to culture
demise. We isolated from VICE bacterial-strains belonging to the Roseobacter and Marinobacter
clades, as indicated by 16S gene marker. Furthermore, we characterized the interaction between
the original VICE bacterial-consortium or each of the bacterial isolates and E. huxleyi. Using flow
cytometry and cell-death markers we showed that E. huxleyi cultures decline along with
proliferation of bacteria. This effect seems to be prominent during E. huxleyi stationary phase.
This suggests that the release of key infochemicals from the algal-host during stationary growth
elicits pathogenic attack by bacteria, resulting in induction of E. huxleyi cell death. Future steps
will involve fluorescence in situ hybridization and quantitative PCR to further characterize and
quantify this interaction, using E. huxleyi cultures and environmental samples collected in the
North Atlantic. We therefore aim to explore the ecological significance of lytic bacteria on E.
huxleyi cell fate during bloom succession and to elucidate the molecular basis for this still
underexplored interaction.
ISRAMAR-BIO – THE ISRAEL NATIONAL MARINE BIOLOGICAL DATABASE
Dafna Ben Yosef1 and Moshe Tom1
Israel Oceanographic and Limnological Research (IOLR), [email protected]l.com; [email protected]
ISRAMAR-BIO, a Marine Bio-Geographic and Ecological Database, is an initiative of the Israel
Oceanographic and Limnological Research (IOLR) under construction. It is part of the Israel
Marine Data Center – ISRAMAR (www.ocean.org.il). Its aim is to extract in a uniform and
comparable format, all the bio-geographic data that was accumulated since the beginning of
surveys/monitoring in the Israeli marine environment. At present the database is loaded in an
ACCESS platform, and limited to the Mediterranean coast of Israel. Around 660 documents
(articles, dissertations and reports) since 1826 are already cited in the database, 463 of them are
deposited as PDF documents, enabling convenient extraction of data. The biologists of IOLR are
responsible for scientific accuracy in their field of expertise and the ISRAMAR team is responsible
for the development of analytical tools and integration to the already public ISRAMAR. The
information unit in the database is the record - the individuals of a specific species that were
sampled in a specific time and location. Each record is accompanied by the following data items:
three taxonomy levels of the sampled species (class, order, family), citation of the source of
information, geographic location, water depth, habitat type, the bio-geographic region of the
species bordering the coast of Israel, molecular taxonomy data (barcoding) when available, and
textual description. To date, over 6555 records have been introduced already. Quantitatively, the
database is built of two levels, the basic presence information, the lowest common denominator
among samples which enables comprehensive inter-sample comparisons and a higher level,
comparable only for limited projects, of quantitative data. The database enables analysis across
time, space and taxa as well as identification of trends of change in the biotic composition in the
Israeli marine environment. When required, the data is adapted to international databases
enabling exchange of information.
CAN INTERNAL WAVES BE USED AS A COMPASS?
Igal Berenshtein1,2 ,Hezi Gildor3, Yaela Reuben1,4, Ofri Mann1,2 and Moshe Kiflawi1,2
1
Department of Life Sciences, Ben-Gurion University, Be’er Sheva 84105, Israel [email protected]
The Interuniversity Institute for Marine Sciences of Eilat, PO Box 469, Eilat 88103, Israel
3
Institute of Earth Sciences, The Hebrew University, Jerusalem, Israel
4
Department of Evolution, Systematics and Ecology, The Hebrew University of Jerusalem, Israel
2
"Internal waves" occur when stratified waters are perturbed by topographic or hydrological
features; e.g. an underwater mountain or a river flood. The amplitude of such waves is often few
tens of m, and can get to few hundreds of m. An observer situated at a fixed depth would
perceive the propagating wave as gradual, periodic changes in water properties, such as
temperature. Moving through the water column at a constant speed, the observer would sense a
Doppler shift in wave frequency, with the magnitude of the shift depending on its direction
relative to that of the wave. We hypothesize that these shifts can be used by marine animals for
the purpose of orientation. We present results from computer simulation, which show how
horizontal swimming directionality can be enhanced when using the information content of
internal waves. Model parameters, such as sensitivity to temperature differentials and internalwave frequencies, were set to correspond with published values; placing our model within the
realm of the plausible.
‫האם וכיצד משתקפת ההגירה הלספסית של מיני דגים לים התיכון בהרכב‬
‫התזונתי של הדולפינן המצוי והדולפין המצוי קצר החרטום בחוף הישראלי?‬
‫דנה ברנד‬
‫החוג לציוויליזציות ימיות – אוניברסיטת חיפה‪[email protected] ,‬‬
‫המחקר עוסק בהרגלי התזונה של הדולפינן המצוי‪ Tursiops truncatus )Montagu, 1821( ,‬והדולפין‬
‫המצוי קצר החרטום ‪ )Linnaeus, 1758( Delphinus delphis -‬החיים לאורך החוף הים‪-‬תיכוני הישראלי‬
‫ומנסה לבחון כיצד הם מושפעים על ידי התהליך המואץ של פלישת מינים ים‪-‬סופיים לים התיכון‬
‫דרך תעלת סואץ‪ .‬הנחת המחקר‪ :‬היות ומזונם של שני המינים מורכב בעיקר מדגים ובהיות הדולפינן‬
‫המצוי בעיקר מין סתגלתן בהרגלי הטריפה ובהרכב מזונו‪ ,‬ההנחה היא שתפריט תזונתם של שני‬
‫המינים יהיה מושפע במידה קטנה או גדולה יותר מההגירה הלספסית‪ .‬לצורך מיפוי מרכיבי מזונם‬
‫של הדולפינים‪ ,‬נבחנו תכולותיהן של ‪ 41‬קיבות של דולפינים שהוחפו בין השנים ‪14 .4112-4114‬‬
‫קיבות של דולפינים ממין דולפינן מצוי ו‪ 4 -‬קיבות של דולפינים ממין דולפין מצוי קצר חרטום ‪.‬‬
‫תכולות הקיבות סוננו ומהשיירים בודדו אוטוליתים לשם זיהוי הדגים‪ .‬מלאכת הזיהוי התבצעה על ידי‬
‫השוואה לצילומי אוטוליתים של דגים לספסיים ודגים אופייניים לדייג המסחרי ולשלל הלוואי‬
‫בישראל‪ .‬תוצאות המחקר גילו כי מבין ‪ 1,2,2‬האוטוליתים שזוהו (‪ 1,1,4‬אצל הדולפינן המצוי ו‪024 -‬‬
‫אצל הדולפין המצוי)‪ 1,1,4 ,‬אוטוליתים זוהו כאוטוליתים השייכים למינים שונים של דגים לספסיים‪.‬‬
‫אצל הדולפינן המצוי ‪ 2,1‬אוטוליתים מויינו וזוהו כשייכים ל‪ 7-‬מינים שונים של דגים לספסיים‪ ,‬ואצל‬
‫הדולפין המצוי ‪ 121‬אוטוליתים זוהו כשייכים ל‪ 4-‬מינים שונים של דגים לספסיים‪ .‬משמעות הדבר‬
‫היא כי מעל ‪ 40%‬מהדגים המזוהים בקיבות הדולפינים היו דגים לספסיים‪ ,‬וכי חלק מהמינים‬
‫המקומיים שנכחו בתפריט הדולפינים בשנים קודמות לא נמצאו בדולפינים בשנים האחרונות‪ .‬יחד‬
‫עם זאת‪ ,‬לא כל המינים המהגרים הידועים כקיימים ונפוצים באזור המחייה של הדולפינים נאכלו‪.‬‬
‫מכאן‪ ,‬הדולפינים משנים את הרגלי האכילה שלהם בהתאם להרכב אוכלוסיית הדגה המקומית‪,‬‬
‫אולם הם עדיין בוררים את מזונם ואוכלים רק מינים מסוימים ולהגירה הלספסית ישנה חשיבות‬
‫והשפעה על כך‪.‬‬
PALEO- TSUNAMI EVENT RECONSTRUCTION USING SEDIMENT CORES ALONG
THE UPPER SHELF OF THE EASTERN MEDITERRANEAN BASIN- CAESAREA
AND JISR AL-ZARKA, ISRAEL
Braun Y., Tyuneleva N., Ben-Avraham Z. and Goodman-Tchernov B.N.
The Leon H. Charney school of marine sciences, University of Haifa [email protected]
Recent research argues for the presence of tsunami deposits offshore Caesarea. Jisr Al-Zarka, to
the north of Caesarea, would presumably have been impacted by some, if not all, of these same
events. A 2.18 m sediment core, from 15.3 m water depth off the coast of Jisr Al-Zarka, was
collected and studied for paleo-environmental reconstruction and correlation of anomalous
(possibly tsunamigenic) horizons. After extraction, the core was described, documented,
photographed, then sampled at 1cm intervals for multi-proxy analysis including granulometry,
micropaleontology, XRF, and FTIR measurements. The aim of the analysis was to reconstruct the
environmental trends and determine the general character and sedimentological history of typical
background sediments versus anomalous horizons. At least one distinct tsunami event and two
possible ones were identified and can be correlated to tsunami layers from offshore Caesarea. By
comparing similar cores from different locations along the upper shallow continental shelf in the
eastern Mediterranean basin we reassert the validity of this approach for discovering, identifying
and studying continuous records of paleo-tsunami events that occurred during the Holocene.
Preliminary evidence suggests that for tsunami events the sedimentological fingerprint can vary
greatly from place to place, even at very short distances, due to changes in bathymetry, coastal
morphology and differing sediment regimes.
MARINE CONSERVATION PLANNING FOR ISRAEL’S WATERS IN THE
MEDITERRANEAN SEA
Eran Brokovich1, Salit Kark2, Tessa Mazor2, Pierre-Elie1 Jablon and Noam Levin1
1
The Remote Sensing Lab, Dept. of Geography, The Hebrew University of Jerusalem, Mount Scopus, Israel
[email protected]
2
ARC Centre of Excellence for Environmental Decisions (CEED), The School of Biological Sciences, The
University of Queensland, QLD, Australia
Various stressors threaten biodiversity creating challenges for conservation efforts in the
Mediterranean Sea from the shore to deep waters. Less than 1% of the Mediterranean Sea is
currently allocated to marine protected areas (MPA), and only in recent years systematic
conservation planning approaches have begun to be implemented. Most work was assigned to
shallow waters within the territorial waters while areas within exclusive economic zones (EEZ) have
been neglected. Conservation planning at the EEZ scale has not been done for any Mediterranean
country and requires addressing vast data gaps and immense economic pressures for resource
exploitation. The eastern Mediterranean, and especially the Israeli EEZ, pose an interesting case
study due to recent natural gas discoveries, the growing importance of desalination, marine
boundary conflicts in the region and Israel’s Nature and Parks Authority’s advancing of new MPAs
within Israel’s territorial waters. We applied the MARXAN decision support tool to develop the first
systematic conservation plan for Israel’s Mediterranean EEZ. We prioritized areas aiming to
maximize conservation targets while minimizing threats to biodiversity and costs of action. While
data on biodiversity at the whole EEZ scale is limited and the task is challenging, we used fish
distribution range data as well as environmental surrogates for the scarce biodiversity data (i.e.
bathymetry, special substrate features, sediment type etc). We complemented these with a range
of spatially-based available data of the threats and the costs of biodiversity conservation.
Comparing a range of zoning and prioritization scenarios that include and compare different
threats, we were able to identify priority areas in Israel’s Mediterranean waters that require future
conservation attention. This work can be used to support the effort for integration of conservation
considerations into the current and future planning in the region in the face of recent developments
and economic initiatives in the sea.
ECHINOID COMMUNITY STRUCTURE AND RATES OF HERBIVORY AND
BIOEROSION ON EXPOSED AND SHELTERED REEFS
Omri Bronstein and Yossi Loya
Department of Zoology, George S. Wise Faculty of Life Science, Tel-Aviv University, Tel Aviv 69978
[email protected], [email protected]
Echinoid-habitat relations are complex and bi-directional. Echinoid community structure is
affected by the habitat structural and environmental conditions; while at the same time,
echinoids may also act as 'reef engineers', able to alter marine environments on a wide
geographic scale. In particular, echinoids play a major role in bioerosion and herbivory on coral
reefs. Through feeding, echinoids reduce algal cover, enabling settlement and coral growth.
However, they also remove large parts of the reef hard substrata, gradually leading to reef
degradation. We compared coral and macroalgae abundance, echinoid community structure and
species-specific rates of echinoid herbivory and bioerosion on reefs subjected to different
intensities of oceanic exposure. Spatio-temporal variations in coral and macroalgae cover were
monitored, and populations of the most abundant echinoid species were compared between
Zanzibar's eastern exposed reefs and the western sheltered ones. To account for the effect of
management, we included marine protected areas (MPAs) from both exposed and sheltered reefs
to our comparison. Coral and macroalgae cover presented a conspicuous contrasting pattern
across exposed and sheltered sites. While coral dominance and lack of macroalgae were
prominent on sheltered reefs, low coral cover and moderate-high macroalgae cover was found on
exposed reefs. Bioerosion was also significantly higher on exposed reefs than on sheltered ones
(4.2-13 and 1.2–3.9 kg CaCO3 m-2 year-1, respectively). The highest rates recorded, at almost 7
kg CaCO3 m-2 year-1, are among the highest echinoid bioerosion rates known to date.
Management had a substantial effect on habitat and echinoid community structure, as coral cover
was significantly higher, macroalgae cover lower, and echinoid densities generally reduced on
MPAs regardless of exposure intensity. Our findings suggest that exposed reefs are susceptible to
markedly higher degrees of echinoid bioerosion; however, adequate management measures can
significantly reduce these rates, consequently altering the reef's trajectory for degradation.
PHOTOPERIOD, TEMPERATURE AND FOOD AVAILABILITY AS DRIVERS OF
THE ANNUAL REPRODUCTIVE CYCLE OF THE SEA URCHIN ECHINOMETRA SP.
FROM THE GULF OF AQABA (RED SEA)
Omri Bronstein and Yossi Loya
Department of Zoology, George S. Wise Faculty of Life Science, Tel-Aviv University, Tel Aviv 69978
[email protected], [email protected]
In spite of the efforts exerted in the search for the environmental factors that regulate discrete
breeding periods in marine invertebrates, they remain poorly understood. Here we present the
first account of the annual reproductive cycle of the pan-tropical sea urchin Echinometra sp. from
the Gulf of Aqaba/Eilat (Red Sea), and explore some of the main environmental variables that
drive echinoid reproduction. Monthly measurements of gonado-somatic indexes and histological
observations of 20 specimens revealed a single seasonal reproductive cycle with gametogenesis
in males and females being highly synchronized. Gametogenesis commenced in June and peak
spawning occurred between September and October. Gonado-somatic indexes were significantly
correlated with seawater temperatures but not with photoperiod. The latter cycle lagged behind
the gonado-somatic cycle by two months, suggesting that the onset of gametogenesis
corresponds to shortening day length, while spawning may be driven by warming seawater
temperatures. Gonads remained quiescent throughout the winter and spring (January through
May) when temperatures were at their lowest. Chlorophyll-a concentrations increased
significantly in the months following spawning (October through January). The high
concentrations of chlorophyll-a in the months following spawning are indicative of high
phytoplankton abundance, and may reflect the increase in food availability for the developing
larvae and newly metamorphosed juveniles. Of the external test dimensions, length presented
the highest correlation to body weight, pertaining length as the best predictor for body size in
Echinometra. Neither sexual dimorphism nor size differences between males and females were
detected, and the sex ratios were approximately 1:1 in three distant Echinometra populations.
The risks and consequences that such environmentally regulated reproduction might face due to
anthropogenic disturbances to the marine environment, stresses the need to deepen our
understanding of the factors that drive and regulate reproduction in broadcast spawning species.
LINEAR INSTABILITY OF WARM CORE, CONSTANT POTENTIAL
VORTICITY, EDDIES IN A TWO LAYER OCEAN
Yair Cohen1, Yona Dvorkin2 and Nathan Paldor1
1
Fredy and Nadine Herrmann Institute of Earth Sciences, Edmond J. Safra Campus, Givat Ram, The Hebrew
University of Jerusalem, Jerusalem, 91904 Israel [email protected]
2
Geological Survey of Israel, Jerusalem - Israel
Linear instability of warm core eddies of constant potential vorticity (PV) is studied in a two layer,
finite depth, shallow water ocean. The basic state flow in the constant PV eddy that obeys the
gradient balance cannot be described by explicit expressions and can only be solved numerically.
The various cases of gradient balanced are classified by constructing a canonical formulation of
this balance. This canonical formulation relates any PV value to a value of the angular velocity
which prevails near the center of the constant PV eddy. The growth-rates of perturbations
imposed on the basic state are calculated for a variety of values of the (constant) PV and the
depth of the surrounding ocean. The growth-rates (i.e. the eigenvalues) are calculated
numerically by employing a shooting to fitting point method that guarantees that the
corresponding eigenfunctions are regular at all singular points and the maximal growth-rates are
mapped as functions of PV and ocean depth for azimuthal wavenumber 2 and 3. The maximal
growth-rate found in our calculations is of the order of 1 day which is similar to that of a solidly
rotating eddy but the range angular velocity and ocean depth where the constant PV eddy is
unstable is greatly reduced compared to that of a solidly rotating eddy. The instabilities found
here are classified in terms of wave-wave interactions by comparing our results in each PV value
with the known instabilities of the solidly rotating eddy with the same angular velocity. In the
constant PV eddy the Baroclinic instability is filtered out and the range of angular velocity where
the Hybrid instability exists is significantly reduced. All instabilities decay monotonically with the
increase in ocean depth.
‫רביית אמנונים (אמנון גליל‪ ,‬א‪ .‬ירדן‪ ,‬א‪ .‬מצוי) בכנרת‪ :‬איתור ואפיון אתרי קינון‬
‫דוד קמינגס‪ ,1,2‬אביטל גזית‪ ,1‬תמר זהרי‪ 2‬ומנחם גורן‬
‫‪1‬‬
‫‪1‬אוניברסיטת ת"א ‪[email protected]‬‬
‫‪4‬המעבדה לחקר הכנרת‪ ,‬חיא"ל‬
‫קריסת יבול אמנון הגליל בכנרת משלל של למעלה מ‪ ,11-‬טון ב‪ 4114-‬לפחות מ‪ 11-‬טון ב‪4112-‬‬
‫היווה אינדיקטור לבעיה בממשק‪ .‬לקריסת אוכלוסיית אמנון הגליל יש כנראה מספר סיבות ואחת‬
‫מהן היא מחסור באתרים מתאימים להטלה במפלסים נמוכים‪ .‬רביית אמנונים בכנרת נחקרה בעבר‪,‬‬
‫אך עבודות אלו נעשו לפני כמעט שלשה עשורים‪ ,‬כאשר טווח תנודות המפלס היה קטן מהנוכחי‬
‫וכאשר התשתית והכסות הצמחית ברצועת הליטורל‪ ,‬בה הדגים מקננים‪ ,‬היו שונים מהקיים בשנים‬
‫האחרונות‪ .‬לשם הבנת צורכי הרבייה של האמנונים בכנרת נדרש מחקר לאיתור אתרי ההטלה‬
‫והערכת התאמתם‪ .‬מספר אתרים מייצגים נדגמו שוב ושוב לאורך כל העונה‪ .‬עקבנו אחר מספר‬
‫הקינים ליחידת שטח לאורך חתכים ניצבים לקו המים‪ ,‬תוך כדי אפיון סביבת הדיגום‪ .‬שיא עונת‬
‫הרבייה של האמנונים בשנת היה בין אפריל לאמצע יוני‪ .‬הפיזור המרחבי של הקינים היה הטרוגני‬
‫מאד‪ ,‬גם בין תחנות דיגום‪ ,‬גם בין חתכים באותה תחנה‪ ,‬וגם בין משבצות לאורך אותו חתך‪ .‬צפיפות‬
‫הקינים ל‪111-‬מ‪ 4‬נעה בין אפס למאות קינים‪ ,‬כאשר ממוצע של ‪ ,1‬קינים ל‪111-‬מ‪ 4‬אפיין את שיא‬
‫עונת ההטלה‪ .‬אתרי ההטלה היו פז ורים סביב האגם כולו ולא היו מרוכזים באופן חריג בבטיחה‪.‬‬
‫באפריל ומאי האמנונים קיננו במים הרדודים (פחות מ‪ 1.4-‬מ')‪ ,‬החל מיוני הם קיננו גם במים עמוקים‬
‫יותר‪ ,‬של ‪ 1-1.4‬מ'‪ .‬אמנונים העדיפו באופן בולט לקנן על תשתית חולית אך נמנעו לקנן באזורים‬
‫חוליים חשופים ללא מסתור‪ .‬בלטה העדפה לקינון בצמוד לתשתיות מבניות‪ ,‬למשל סמוך לצמחייה‬
‫מוצפת‪ ,‬בתוך סבך צמחייה או סמוך לאבנים‪ .‬בעבר רווחה הדעה שעיקר הרבייה של אמנוני הכנרת‬
‫מתרחשת באזור הבטיחה‪ .‬ממצאי עבודה זו מראים כי ישנה פעילות רבייה משמעותית בכל היקף‬
‫האגם‪ ,‬עובדה הראויה התייחסות במי וחד לאור מצב המפלסים העכשווי בו מרבית הבטיחה יבשה‬
‫בעונת הרבייה של אמנוני הכנרת‪.‬‬
SEASONAL-SCALE MORPHOLOGICAL EVOLUTION OF THE BEACH AND SEACLIFF ALONG THE SHARON ESCARPMENT
Onn Crouvi, Oded Katz and Amit Mushkin
Geological Survey of Israel, 30 Malkhe Israel St., Jerusalem 95501, Israel [email protected],
[email protected], [email protected]
Many of the worlds sandy beaches, including the Mediterranean Israeli coast, exhibit strong
seasonal morphodynamic cycles. A quantitative understanding of this seasonal cycle is critical for
a variety of applied coastal problems. Although the sea-cliff can serve as an additional sediment
supplier to the beach, it is often neglected in sediment budget calculations along the beach. Here
we study the seasonal-scale beach morphological evolution along the Sharon region, which is
characterized by a prominent and actively retreating sea-cliff. The study goals are to quantify the
seasonal to interannual beach change rates and to assess the role of the retreating sea-cliff as
sand supplier for beach change at these scales. We collected cross-shore topographic profiles
using GPS-RTK every few months at two study sites (Gaash and Neurim). At each site we
measured 10 profiles from the cliff-base westward until a water depth of ~1.4 m along 100 m
beach long stretch. The measurements were interpolated into surface maps that were subtracted
from each other to estimate the volume and spatial distribution of erosion and accretion at the
given time interval. Preliminary results from three seasons reveal that at Gaash all profiles
showed beach erosion during the fall that accelerated in the winter. Neurim exhibited a more
complicated pattern in the fall, with concurrent erosion and deposition in different parts of the
beach, whereas erosion prevailed during the winter. The cliff face exhibited only minor changes
during this time period in the form of few relatively small collapses. Yet, erosion of existing talus
deposits led to accumulation of cliff sediments along the beach in front of these taluses. Ongoing
repeat measurements of the beach and cliff will allow us to quantify the role of the cliff in
affecting beach dynamics on interannual scale.
MODELING THE EFFECT OF SEA-LEVEL RISE ON BIODIVERSITY OF VERMETID
REEFS USING HIGH-RESOLUTION TERRESTRIAL LASER SCANNING
Niv David1,2, Reuma Arav3, Sagi Filin3, Dorit Sivan1 and Gil Rilov2
1
Department of maritime civilizations, Leon H. Charney School of Marine Sciences, University of Haifa
[email protected]
2
National institute of oceanography, Israel Oceanographic and Limnological Research
Faculty of Civil and Environmental Engineering, Technion
3
The Eastern Mediterranean rocky shore is characterized by broad biogenic eolianite or limestone
abrasion platforms, known as vermetid reefs. These platforms support a distinctive coastal
ecosystem at the intertidal zone, featuring a diverse community of marine species, many of which
are limited to the intertidal zone.
This coastal ecosystem is characterized by a complex micro-topography and poorly-studied
species-habitat relationship. Its proximity to mean sea-level exposes it to a possible risk of
becoming continually submerged due to predicted sea-level rise, thus losing its characteristic
intertidal community. We demonstrate a novel application of high-resolution terrestrial laser
scanning, combined with biodiversity sampling, to create a geomorphological and ecological
representation of the rocky intertidal coastal system that includes its topographical complexity,
relative and absolute elevations, species-habitat relationship and potential ecological impacts of
sea-level rise.
We found height differences between platform levels of single reefs and between reefs within and
among sites, ranging from 13 cm to 50 cm above mean sea-level, and significantly richer benthic
community at higher platform levels. There is a clear absence of most strictly-intertidal species on
mostly-submerged platforms and at the shallow subtidal zone. Our findings suggest that even a
mild rise in sea level (a few tens of decimeters), based on the low-end estimates of the IPCC
climate change scenarios, will gradually submerge the vermetid reefs in the next few decades.
Due to the fact there are no horizontal habitats higher on the shore and because the main
organism responsible for the biogenic formation (Dendropoma petraeum) is almost extinct, sea
level rise will result in greatly reduced intertidal habitats and some biodiversity loss along the
shore. A more pronounced sea-level rise (meter or more) may result in extensive biodiversity
change and total community shift.
PHOTOHETERHOPY IN A MESOSCALE ANTICYCLONIC EDDY IN EASTERN
MEDITERRANEAN SEA
Vadim Dubinsky, Ilia Burgsdorf, Nof Atamna-Ismaeel, Eddie Fadeev, Elad Rachmilovitz, Daniel Sher
and Laura Steindler
Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel 31905,
Haifa, Israel [email protected] , [email protected] , [email protected] , [email protected] ,
[email protected] , [email protected] , [email protected] ;
Photoheterhophic bacteria can use light to generate biochemical energy for transport and metabolic
needs, but unlike photosynthetic organisms, they are depended on organic carbon compounds for
biomass accumulation. Photoheterhophs include proteorhodopsin-bearing bacteria, which constitute a
considerable fraction of marine planktonic bacteria. Thus, they might contribute significantly to the
carbon cycle and impact oceanic food webs. Mesoscale eddies are semi-closed rotating bodies of water
with distinct physico-chemical properties and are a widespread phenomenon in the world’s oceans.
Previous studies found that eddies can have variable effects on phytoplankton community structure,
primary productivity and nitrogen fixation. The current study was designed to assess the abundance of
photoheterophic genes (pr) and transcripts across an offshore anticyclonic eddy. In November 2013 we
identified an anticyclonic eddy 115km west off the Israeli coast, south of Cyprus, using the Cyprus
Coastal Ocean Forecasting and Observing System. Satellite remote sensing indicated positive sea level
anomaly and flow vectors showed circular clockwise circulation indicative of an anticyclone. We sampled
seawater for DNA, RNA, inorganic nutrients, pigments and cells density in transect across the eddy on
board the R/V Mediterranean Explorer. In addition physical characteristics such as vertical upper ocean
profiles of temperature, salinity, oxygen and fluorescence were obtained with shipboard mounted CTD
profiler. Nutrient analysis revealed a significant decrease of nitrogen (NO 2+NO3) towards the eddy’s
center, probably due to the surface water downwelling, creating an ultra-oligotrophic environment.
Bacterial cell density also decreased towards the eddy’s center. However, real-time qPCR showed that
SAR11-group pr genes were considerably more abundant in the eddy’s center, supporting the hypothesis
that photoheterhophy confers an advantage that enables bacteria to survive starvation conditions.
In
addition we will present pyrosequencing data used to determine pr’s diversity and to quantify the
abundance and expression of other common photoheterhophic groups found in the sampled location.
RESPONSE OF NEMATOSTELLA VECTENSIS TRANSCRIPTOME TO HEAVY
METALS
Elran R1., Raam M1., Kraus R1., Brekhman V1 ., Chalifa-Caspi V.2 and Lotan T.1
1
Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa; Israel ,
[email protected], [email protected], [email protected] ,[email protected],
[email protected]
2
Bioinformatics Core Facility, National Institute for Biotechnology in the Negev, Ben-Gurion University of the
Negev, Israel, [email protected]
The rapid growth of industrial infrastructures along seashores and the increase in marine traffic
are primary causes of the extensive deposition of metals in the ocean today. These pollutants
have a profound deleterious effect on Cnidarian organisms and ecosystems. Cnidarians have
evolved 700 million ago and they possess a worldwide distribution and play an important role in
the marine ecosystem. They are the main reef builders and act as both predators and prey in the
marine ecosystem. we investigate the effect of heavy metals on the regulatory defense
mechanisms of an emerging cnidarian genetic model, the marine starlet sea anemone
Nematostella vectensis, as its full genome has been published and its sexual cycle can be
controlled under laboratory conditions. The response of Nematostella vectensis to four heavy
metals Hg, Cd, Cu and Zn was tested using RNA next generation sequencing (Illumina HiSeq
2000). The differentially expressed genes were analyzed and grouped by functional categories.
Only limited number of genes was common between the four metal treatments whereas, most Cu
expressed genes were also expressed in Hg treated anemones.
defense pathways to the exposed metals will be discussed.
The different and common
‫קניון אכזיב כגורם מעצב של מארג המזון האזורי‬
‫מיה רודיטי‪-‬אלסר‪ ,1,2‬דני כרם‪ ,1,2‬דרור אנג'ל‪ ,1‬מייקל לזר‪ ,3‬לאורה שטיינדלר‪ ,2‬ברק חרות‪ ,5‬אפרת‬
‫‪7‬‬
‫שוהם‪-‬פרידר‪ ,5‬אורית ברנע‪ 6‬ואהובה אלמוגי‪-‬לבין‬
‫‪ 1‬החוג לציוויליזציות ימיות‬
‫‪ 4‬מרכז חקר‪ ,‬מידע וסיוע ליונקים ימיים לישראל‬
‫‪ ,‬החוג למדעים גיאו‪-‬ימיים‬
‫‪ 2‬החוג לביולוגיה ימית‪ ,‬ביה"ס למדעי הים ע"ש ליאון צ'רני‪ ,‬אוניברסיטת חיפה‪.‬‬
‫;‪( [email protected]; [email protected]; [email protected]; [email protected]‬‬
‫) ‪[email protected]‬‬
‫‪ 4‬המכון לחקר ימים ואגמים לישראל ( ‪)[email protected]; [email protected]‬‬
‫‪ 0‬ביה"ס למדעי הים‪ ,‬המרכז האקדמי רופין‪)[email protected] ( .‬‬
‫‪ 7‬המכון הגיאולוגי לישראל (‪)[email protected]‬‬
‫קניונים תת‪-‬ימיים‪ ,‬בשל מאפייניהם הפיזיקליים הייחודיים ברחבי העולם‪ ,‬נמצאו כמוקדי יצרנות ומגוון‬
‫ביולוגי‪ .‬קניון אכזיב הוא אחד מעשרה קניונים תת‪-‬ימיים עיקריים החורצים את מדף ומדרון היבשת‬
‫הצרים בדרכם אל הים העמוק במרחק קצר מאוד מהחוף‪ ,‬מול חופי צפון ישראל ודרום לבנון‪.‬‬
‫תחילתו של קניון אכזיב כשלושה ק"מ מערבית לשפך נחל שעל שבגליל המערבי וסופו‪ ,‬בתום‬
‫מסלול תלול של ‪ 21‬ק"מ‪ ,‬בעומק מים של ‪ 1,11‬מ'‪ .‬ככזה‪ ,‬מהווה הקניון את בית הגידול היחידי‬
‫לאורך מדף היבשת הישראלי בו הים העמוק נמצא כה קרוב לחוף‪ .‬מאפיין ייחודי זה בשילוב ההנחה‬
‫שקניון אכזיב לא יהא שונה מדומיו בעולם‪ ,‬הובילו את רשות הטבע והגנים לפתוח בהליכים להכרזת‬
‫הקניון וסביבתו הקרובה כשמורת טבע ימית‪ .‬הנחה זאת עדיין לא הוכחה היות והביוטה של הקניון‬
‫מעולם לא נסקרה בצורה שיטתית‪ .‬במהלך סקרים שגרתיים לאיתור יונקים ימיים בין ראש הנקרה‬
‫למפרץ חיפה‪ ,‬נמצא כי רוב הפרטים ממין דולפינן מצוי (‪ )Tursiops truncatus‬נצפו מעל קניון אכזיב‪.‬‬
‫ממצא זה הוביל למחקר הנוכחי בו מתבצע דיגום של נציגים מרמות טרופיות שונות בעומקים שונים‬
‫בתוך הקניון ומחוצה לו‪ ,‬במדרון הסמוך‪ ,‬במטרה לבדוק האם קניון אכזיב מהווה מוקד יצרנות‪ ,‬אשר‬
‫יהיה בעל השפעה משמעותית באזור האוליגוטרופי של מזרח הים התיכון‪ .‬במהלך שבע הפלגות‬
‫מחקר בין השנים ‪ 4111-411,‬נאספו דגימות מים לריכוזי כלורופיל‪ ,‬נוטריינטים וחיידקים‪ ,‬גרירות‬
‫פלנקטון אנכיות ודגימות קרקעית לבדיקות אוכלוסיית החי בתוך המצע‪ ,‬ריכוזי חומר אורגני וגודל‬
‫גרגר‪ .‬במקביל נמשכו סקרי היונקים הימיים‪ .‬תוצאות ראשוניות מצביעות על מספר פרטים ממוצע‬
‫ומגוון מינים (‪ ‬סטיית תקן) גבוה יותר בקרב חסרי החוליות שנמצאו בקרקעית הקניון‪ ,‬לעומת‬
‫נקודות ביקורת בעומקי מים דומים במדרון ( ‪ 26.9±49.1‬לעומת ‪ 5.2±7.2‬אורגניזמים ‪ 411 /‬מ"ל;‬
‫‪ p=0.023‬ו‪ 6±4.4‬לעומת ‪ 411 / 2.3±2.1‬מ"ל; ‪ ,p=0.014‬בהתאמה)‪ .‬מספר מינים פלנקטוניים‬
‫ובנתוניים נמצאו ייחודיים לקניון בלבד‪ .‬עובדות אלו מגבירות את הסיכוי כי קניון אכזיב אכן יוכח‬
‫כבית גידול ייחודי ומגוון הראוי לשימור ובכך מצדיקות את בחירתו כבסיס לשמורה הימית הצפונית‬
‫המוצעת‪.‬‬
TOWARDS THE PHYSIOLOGICAL AND GENOMIC CHARACTERIZATION OF TWO
MARINE ALTEROMONAS STRAINS, SELECTED BASED ON THEIR
CONTRASTING INTERACTIONS WITH PROCHLOROCOCCUS
Eduard Fadeev
Haifa University [email protected]
Ecological interactions between marine microorganisms, such as allelopathy competition and
symbiosis, are prevalent and important in the oceans. Here, we present a preliminary
physiological and genomic characterization of two strains of marine Alteromonas, chosen based
on strongly contrasting effects when grown in co-culture with Prochlorococcus, a globallyabundant marine primary producer: one enhances Prochlorococcus growth and one inhibits it.
Significant differences were observed between the two strains, both in their growth rates and in
their range of carbon substrate utilization. We are currently assembling the genome of one of the
two Alteromonas strains, HOTo1A3, using a combination of de-novo and reference based
assembly of a single 72 bp paired end library. Using this approach we have succeeded in reducing
the number of the contigs from 300-700 to 13. Whereas initial read mapping suggested that
HOTo1A3 is closest to ATCC 27126, a strain also isolated near Hawaii, many genes are in fact
more similar to those of strain isolated from the English Channel (673). This raises the question
of what processes shape these genomes and their distribution in the oceans. These results will
help elucidate the molecular basis of the interactions between Alteromonas and Prochlorococus,
and to search for such interactions in the marine environment.
ESTIMATING SUBMARINE GROUNDWATER DISCHARGE INTO THE ENTIRE
MEDITERRANEAN SEA BY USING 228RA
Valentí Rodellas1, Jordi Garcia-Orellana1, Mor Feldman2,3, Pere Masqué1, Yossi Yechieli3 and
Yishai Weinstein2
1
Institut de Ciència i Tecnologia Ambientals and Dep. de Física, Universitat Autònoma de Barcelona,
Barcelona, Spain [email protected]; [email protected]; [email protected]
2
Department of Geography and Environment, Bar-Ilan University, Ramat-Gan, Israel
[email protected]; [email protected]
3
Geological Survey of Israel, 30 Malkei Israel St., Jerusalem 9550 [email protected]
Submarine Groundwater Discharge (SGD), is a major conveyor of land-derived compounds to the
sea. In this study, we aim to assess the extent of the total SGD flux to the entire Mediterranean
Sea (MS) based on a
228
Ra mass balance. Water samples for
228
Ra were collected all over the MS
during the M84/3 (April 2011) and MedSeA (May 2013) cruises onboard of the R/V Meteor and
the B/O Ángeles Alvariño respectively.
228
Ra concentrations ranged from 8-56 dpm·m-3, with
relatively higher concentrations in surface and eastern Mediterranean waters, reflecting the
circulation in the Mediterranean basin. The data was used to construct the
228
the MS (surface and intermediate water). Considering steady state, sinks of
Ra mass balance of
228
Ra mainly include
radioactive decay, but also flow through the straits of Gibraltar and Bosphorous, as well as
exchange with the deep water. Potential sources include riverine inputs, atmospheric dust,
release from shelf and slope sediments, exchange through the straits of Gibraltar and Bosphorous
and SGD, which is the unknown in this study. The total
intermediate water is 3.5(±0.4)·10
16
228
Ra inventory in surface and
dpm. With a half life of 5.75 years, and assuming steady
state, this results in a decay of 42(±5)·1014 dpm·yr-1. Adding this to the mass balance, SGD flux
to the upper and intermediate Mediterranean should be 19(±12)·1014 dpm·yr-1 (i.e. 20-70% of
total
228
Ra inputs). With
228
Ra concentration in SGD ranging from 610 to 2100 dpm·m-3 (the
interquartile range of all the reported Mediterranean SGD), the total SGD flow into the MS is (257)·1011 m3·yr-1. This is similar or higher than the riverine inputs (3.1·1011 m3·yr-1). Since the
concentrations of dissolved compounds in groundwater, in particular nutrients, usually exceed
those in rivers, SGD turns to be a very important component in Mediterranean mass balances and
in coastal Mediterranean biogeochemical cycles.
PATCHY CALCIFICATION PATTERN IN ACROPORA SP. DETERMINED BY
ELECTRON MICROPROBE AND MICRO-SXRF ELEMENT MAPPINGS USING TWO
DISTINCT SR ELEMENT CONCENTRATIONS
Fruchter Noa1,2, Eisenhauer Anton2, Fietzke Jan2, Hansteen Thor2, Appel Karen3 and Erez
Jonathan4
1
GEOMAR-Helmholtz Institute for Marine Sciences, Kiel Germany
Geological survey of Israel, Jerusalem Israel
3
HasyLab- German Electron Synchrotron, Hamburg Germany
4
The Hebrew University of Jerusalem, Jerusalem Israel
2
Electron microprobe and synchrotron X-ray fluorescence micro-analyses were used to study the
calcification pattern of Acropora sp.. Specimens of Acropora sp. were cultured in two stages at
two distinct Sr concentrations in the bulk solutions, where the low concentrations represent the
pre-experiment and the high concentrations represent the conditions during the experiments.
The experimental, high concentrations, Sr comprise both patches on the pre-existing skeleton
walls and growth extensions of the skeleton. We show a clear visualization of the patchy
calcification pattern in Acropora. We assume that the precipitation in older parts of the skeleton is
biogenically controlled. That secondary infilling calcification reduces the porosity and increases
the stability of the skeleton.
IDENTIFYING AND MAPPING THE TRACKS OF RECENT SUBMARINE MASS
SLIDE EVENTS ON THE CONTINENTAL SLOPE OF ISRAEL: A BASIS FOR
FUTURE INFRASTRUCTURE RISK ASSESSMENT
Gadol O.1, Bar-Am G.2, Tibor G.3 and Makovsky Y.1
1
The Dr. Moses Strauss Department of Marine Geosciences, Leon H.Charney School of marine sciences.
Haifa University, Mt. Carmel, Haifa 31905, Israel
2
Modiin Energy, 3 Azriele Center, Triangle Tower 41st Floor, Tel-Aviv 6702301, Israel.
3
Israel Oceanographic and Limnological Researche Ltd., Tel-Shikmona, P.O.Box 8030, Haifa 31080, Israel
Mass sliding events pose a geohazard to marine infrastructures and have been described as the
cause of catastrophic tsunami events. The bathymetry of the continental slope offshore Israel is
etched by a complex array of mass transport escarpments. Some of these escarpments are the
superimposition result of different mass transport features that vary both in the spatial and
temporal scales. Our manual interpretation which was implemented on a 50 m resolution DEM
(acquired by the Bathymetric Survey of Israel and Israel Oceanographic and Limnological
Research) emphasized the complexity of the scars present on the continental slope. Two main
morphometric approaches were combined to investigate the dynamics of the events that shape
the mass transport escarpments, by delineating the bathymetric marks left by each one of them.
Slope gradient and curvature maps were created and classified into categories: break of slope,
convex change of slope, concave change of slope and sloping surface. These classes create
vectors that follow the main escarpments present on the seafloor and map features that are
characteristic for mass transport deposits such as troughs, ridges and blocks. The second
approach utilizes the spectral decomposition of the bathymetric data sets. Through the
implementation of two-dimensional discrete Fourier analyses the original DEM is transformed into
the frequency domain and is subdivided into its main spectral components. These components,
which represent different degrees of surface roughness were later redraped on the original DEM.
When combined, the two methods create a distinction of features such as headscarps, lateral
margins, ridges and troughs as well as a delineation of lobes and sediment flow pathways within
mass transport complexes. At this preliminary stage these methods were applied on two different
bathymetric data sets (originating from seafloor picking of 3D commercial seismic surveys) that
comprise of mass transport escarpments. The first dataset is a 12.5 m resolution DEM of the base
of the slope in southern Israel (Southern Israel seismic block). Spectral decomposition enhanced
the delineation of an mass transport complex toe region comprised of a set of deposition lobes
surrounded by a smoother bathymetric envelope. The later is suggested to be the result of
settling of suspended debris at the end of a sliding event. Also delineated are contourites (100 300 m wide) stretching from surface irregularities, but are overprinted by the slide deposits. The
second dataset is a 25 m resolution DEM from the lower slope of central Israel (Yam Hadera
seismic block). The combined morphometric analysis delineated several superimposed landslide
features. Some of these landslide scars were overprinted by a smoothening erosive flow
originating from upslope diverging channels. These preliminary results demonstrate the potential
of our morphometric approach for deciphering between the cumulative effects of mass transport
processes.
CONNECTIONS BETWEEN THE SPRING BREAKUP OF THE SOUTHERN
HEMISPHERE POLAR VORTEX, STATIONARY WAVES, AND AIR-SEA
ROUGHNESS
Chaim I. Garfinkel1,4, Luke D. Oman2, Elizabeth A. Barnes3, Darryn W. Waugh4, Margaret M.
Hurwitz2 and Andrea Molod2
1
Institute of Earth Sciences, Edmond J. Safra Campus, Hebrew University, Israel
Atmospheric Chemistry and Dynamics Laboratory, , Earth Sciences Division, NASA Goddard Space Flight
Center, USA
3
Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA
4
Department of Earth and Planetry Sciences, Johns Hopkins University, MD, USA
2
A robust connection between the drag on surface-layer winds and the stratospheric circulation is
demonstrated in NASA's Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM).
Specifically, an updated parameterization of roughness at the air-sea interface, in which surface
roughness is increased for moderate wind speeds (4m/s to 20m/s), leads to a decrease in model
biases in Southern Hemispheric surface wind (by up to 1.2m/s), ozone, polar cap temperature,
stationary wave heat flux, and springtime vortex breakup. A dynamical mechanism is proposed
whereby increased surface roughness leads to improved stationary waves. Increased surface
roughness leads to anomalous eddy momentum flux convergence primarily in the Indian Ocean
sector (where eddies are strongest climatologically) in September and October. The localization of
the eddy momentum flux convergence anomaly in the Indian Ocean sector leads to a zonally
asymmetric reduction in zonal wind and, by geostrophy, to a wavenumber-1 stationary wave
pattern. This tropospheric stationary wave pattern leads to enhanced upwards wave activity
entering the stratosphere. The net effect is an improved Southern Hemisphere vortex: the vortex
breaks up earlier in spring (i.e., the spring late-breakup bias is partially ameliorated) yet is no
weaker in mid-winter. More than half of the stratospheric biases appear to be related to the
surface wind speed biases. As many other chemistry-climate models use a similar scheme for
their surface layer momentum exchange and have similar biases in the stratosphere, we expect
that results from GEOSCCM may be relevant for other climate models.
IN VIVO VISUALIZATION OF FLUORESCENTLY LABELED VIBRIO
CORALLIILYTICUS STRAINS’ INTERACTION WITH POCILLOPORA
DAMICORNIS IN A NOVEL MICROFLUIDICS SYSTEM
Assaf R. Gavish, Orr Shapiro, Daniella Schatz and Assaf Vardi
Bacterial populations play a major role in cnidarian health, via symbiosis or pathogenicity, though
the cellular mechanisms involved in the initiation and progression of bacterial infection in these
organisms are not fully understood. Vibrio coralliilyticus (Vc) is a well characterized coral
pathogen that infects the stony coral Pocillopora damicornis (Pd) and causes bleaching or tissue
necrosis in a temperature dependent manner. To elucidate Vc’s mechanisms of infection, we
genetically transformed Vc strains YB-1 and YB-2 with plasmids encoding for the fluorescent
protein DsRed that has fluorescence characteristics that can be distinguished from the coral and
zooxanthellae auto-fluorescence. While YB-1 and YB-2 differ in their ability to express DsRed, in
both cases the bacteria remain motile and are easily distinguished from the coral background.
Importantly, the transgenic bacteria appear to retain their ability to infect the coral host. These
transformed strains are used to visualize infection and disease processes in micro-colonies of Pd
held in a newly developed microfluidics system.
This system enables a high-resolution
fluorescent microscopic observation of the disease process under controlled environmental
conditions. We are currently working on transforming Vc strains with roGFP, a redox biosensor
that can indicate ROS signaling and stress conditions. These newly developed tools will open new
avenues in the study of coral-pathogen interactions, and will promote our understanding of the
role of environmental conditions in bacterial pathogenesis.
SALINITY AND TEMPERATURE TRENDS IN THE SOUTH EASTERN
MEDITERRANEAN
Isaac Gertman, Tal Ozer and Ron Goldman
Israel Oceanographic and Limnological Research, Tel-Shikmona, P.O.B. 8030 Haifa 31080,
[email protected]
The seasonally active layer in the South Eastern Mediterranean (SEM) consists of three water
masses: Levantine Surface Water (LSW), Atlantic Water (AW) and Levantine Intermediate Water
(LSW). The salt content and enthalpy of these water masses reflect long-term fluctuations in air–
sea interaction and water exchange between the SEM and adjacent basins. Analysis of 30 years
of CTD deep-water profiles in the SEM reveals long-term statistically significant increase of
salinity and temperature in LSW, AW and LIW. The most intensive increase is in LSW: 0.01 per
year for salinity and 0.1°C/year for temperature. Lower rates were estimated for AW (0.006 per
year and 0.04°C/year) and LIW (0.05 per year and 0.03°C/year). For comparison, the global
ocean warming rate in the upper 100m layer (IPCC-2013) is about 10 times weaker, though one
can expect stronger warming in inner basins such as the SEM. The salinization process in the
upper layer of the SEM can be attributed to the damming of the Nile in 1964. The rise in salinity
is in agreement with Skliris and Lascaratos (2007), who predicted a rise of about 0.2 in salinity 40
years after the Nile damming. Two evident maxima of salinity in LIW (1992 and 2008) can be
explained in the framework of the Ionian Bimodal Oscillating System (BIOS: Gacic et al., 2010).
Both maxima result from periods of anticyclonic circulation in the north Ionian (1988-1997 and
2006-2009) and limited AW advection to the SEM. The first period led to the Eastern
Mediterranean Transient. The second period ended during 2009, when increase in AW advection
decreased salinity within the SEM. The BIOS signal is masked by the air-sea interaction signal in
LSW and AW, and is therefore, less evident in analysis of these water masses.
DOUBLE DIFFUSION ONFLUENCE ON THE SUMMER DEAD SEA VERTICAL
MIXING
Isaac Gertman1, Tal Ozer1, Boris Katsenelson1 and Nadav Lensky2
1
2
Israel Oceanographic and Limnological Research, Haifa, [email protected]
Geological Survey of Israel, Jerusalem, [email protected]
Profiles of temperature and quasi-salinity during last 10 years, show similar seasonal progression:
development “overturning halocline” and stabilizing thermocline during March-November;
intermitted convective mixing of water body during November-March. The warm and saline
boundary layer is observed also regularly above the bottom. It originates from the southern part
of the sea, where end brinies discharged from the evaporation ponds (Lensky et al., 2005).
Having extremely high salinity (~ 350g/kg) and density (~1350 kg/m3), in spite of the high
summer temperatures (~ 45C), the end brines spread as gravitational currents in the deep
basin. Temperature profiles collected by CTD demonstrate development of step-like structures
both beneath the seasonal pycnocline and above the bottom boundary layer. Estimation of
density ratio for the Dead Sea water (where measurements of water salinity is quite difficult) was
calculated as follows: R= [(/z)]/[(σ32/z)] , where  and  are temperature expansion
and quasi-salinity extraction coefficients for the Dead Sea water (Gertman et al., 2010), θ and σ32
are potential temperature and quasi-salinity. In spite of the low resolution of quasi-salinity data,
the R values are quite reasonable and reveal that the thermohaline structure is appropriate for
development of vertical instability due to double diffusion. Intensive positive salt and heat fluxes
to the middle layer of the water body are generated by salt fingers regime beneath the UML
(1.3< R<2) as well as by diffusive regime above the end brine bottom layer (0< R<1). As result
of the two sided double diffusion processes, the middle layer (40-200 m) is well mixed already in
October, about two months before the first convective overturn.
GRAVITY CURRENTS IN A SYSTEM OF TWO STRATIFIED WATER MASSES
Ron Goldman1, Marius Ungarish2 and Irad Yavneh2
1
Israel Oceanographic and Limnological Research, 31080, Haifa [email protected]
Department of computer Science, Technion, 32000, Haifa [email protected] [email protected]
2
Gravity current is a phenomenon where fluid of one density (the current) flows into a fluid of
different density (the ambient). The driving force of this flow is the horizontal pressure gradient
generated by differences in buoyancy. This phenomenon is common in geophysical flows (e.g.
flow through straits, river discharge, etc'). Here we consider a high Reynolds number Boussinesq
flow field, in which a linearly stratified gravity current is released from a rectangular lock into an
ambient which is also linearly stratified. The system is non-rotating and flat bottomed. A one
layer shallow water model describing this system exists and relates the motion of the current to
the height ratio of the fluids H; the stratification parameters of the ambient and the current (S, σ
respectively). Results of the shallow water model were compared with 2D non-hydrostatic Navier
Stokes simulations. The qualitative predictions of the model are confirmed, in particular: (1) there
is an initial “slumping” stage of propagation in which the front of the current (known as the
“nose” of the current) propagates with constant speed. The front velocity decays in time after the
slumping stage is over; (2) for fixed H and S, the increase of σ causes a slower propagation of
the current; (3) for some combinations of the parameters H, S, σ the fluid released from the lock
lacks initially (or runs out quickly of) buoyancy “driving power” in the horizontal direction, and
does not propagate like a gravity current. There is also a fair quantitative agreement between the
predictions of the model and the simulations concerning the spread of the current. Our
conclusion is that the shallow water model is an effective tool which approximates well the real
flow in many situations, saves significant computational effort, and gives insight into gravity
current phenomena.
PRESERVED OFFSHORE TSUNAMI DEPOSITS RECOGNIZED IN A LOW RISK
ZONE: AN ANCIENT TSUNAMI IN THE NORTHERN RED SEA
Beverly Goodman-Tchernov,1,2 Timor Katz2, Yonaton Shaked2, Nairooz Qupty1, Mor Kanari
Tina Niemi5 and Amotz Agnon6
3,4
,
1
Leon Charney School of Marine Sciences, Moses Strauss Department of Marine Geosciences, University of
Haifa, Mt. Carmel, Israel
2
Interuniversity Institute of Marine Sciences-Eilat, Coral Beach, P.O. Box 469, Israel
3
Tel Aviv University, Tel Aviv, Israel
4
Israel Oceanographic and Limnological Research, Shikmona, Israel
5
University of Kansas-Missouri, Kansas City, MO, USA
6
Hebrew University of Jerusalem, Jerusalem, Israel
Locating tsunami vulnerable areas is central for creating realistic coastal management and risk
plans to prepare for potential disasters. While some regions are known to be prone to tsunami
events, other areas are considered safe because of their geographic and bathymetric settings,
seismic disposition, and lack of written descriptions of past tsunamis. Models that are produced
to estimate risk rely on catalogues of written records and field studies that summarize known
events. Written records are not evenly distributed worldwide, nor has writing always existed.
Field studies of preserved tsunami deposits focus primarily on terrestrial or coastal deposits,
which modern observations of post-tsunami deposit diagenesis are determining that they are
quickly eroded and rarely preserved, thus leading to a considerably patchy record, ultimately
underrepresenting the actual number of past tsunamis. Offshore sedimentary deposits may hold
promise as better recorders of these events.
Here we present new evidence for a rare, yet
significant and potentially very destructive tsunami event that impacted a presumed low-risk
location in the northern Red Sea’s Gulf of Aqaba. The anomalous deposits were recognized within
sediment cores collected offshore (-16 to -12 msl) and were identified using a suite of common
tsunamigenic
indicators
such
as
sedimentological
characterization,
granulometry
and
micropaleontology. Given rapidly expanding coastal populations in the region and worldwide,
these findings are a warning that the current practice of determining risk based solely on models
and historical catalogues, without offshore field studies, is insufficient.
BIG IMPACT OF DOUBLE DIFFUSION PARAMETERIZATIONS IN THE GULF OF
ELAT
Avi Gozolchiani1, Hezi Gildor2 and Yossi Ashkenazy1
1
2
Ben-Gurion University, Midreshet Ben-Gurion, Israel
Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel.
Conditions in favor of double diffusion were identified in the Gulf of Elat. The differnet
parameterization schemes found in literature were applied to these events by extending a
package of MITgcm, and comparing against a new spectral model with 1mm resolution. Finally,
these schemes were applied to a full model of the Gulf of Elat, showing an improvement in
agreement with station data. An additional outcome of this analysis was a discovery of a new
instability regime which was overlooked in earlier studies, exhibiting horizontal fingers. This result
might shed light on the phenomenon of thermohaline staircases.
NONLINEAR INTERACTION BETWEEN A BASIN-WIDE GYRE AND
TOPOGRAPHY IN THE GULF OF ELAT
Avi Gozolchiani1, Hezi Gildor2 and Yossi Ashkenazy1
1
Ben-Gurion University, Midreshet Ben-Gurion, Israel
Institute of Earth Sciences, Hebrew University of Jerusalem,Jerusalem, Israel.
2
In the current work we use a state of the art model (model A) representation of the gulf of Eilat,
developed in Biton et al. (2011), as well as an idealized rectangular setting (model B), to clarify
the relations between basin-wide gyres and topography (both hydrography and horizontal
boundaries). By gradually removing from model A the bottom topography, shorelines and
stratification, and by adding simple shoreline and topographic features to model B we are able to
associate the observed gyres with shoreline and topographic details and reject known linear
mechanisms.
E. Biton, H. Gildor, J. Geoph. Res., 116(C8), 2011.
MEDITERRANEAN AND RED SEA BIOLOGICAL OBSERVATIONS TAXONSPECIFIC DATABASE (BOTS-DB)
Eyal Greengrass, Yevgeniya Krivenko, Tal Ozer, Dafna Ben Yosef, Moshe Tom and Isaac
Gertman
Israel Oceanographic and Limnological Research, Tel-Shikmona, P.O.B. 8030 Haifa 31080,
[email protected]
The knowledge of the space/time variations of species is the basis for any ecological
investigations. While historical observations containing integral concentrations of biological
parameters (chlorophyll, abundance, biomass…) are organized partly in ISRAMAR Cast Database,
the taxon-specific data collected in Israel has not been sufficiently organized. This has been
hindered by the lack of standards, variability of methods and complexity of biological data
formalization. The BOTS-DB was developed to store historical and future available information
related to marine species observations and related metadata. The DB’s logical unit is information
regarding a specimen (taxa name, barcode, image), related attributes (abundance, size, age,
contaminants…), habitat description, sampling device and method, time and space of sampling,
responsible organization and scientist, source of information (cruise, project and publication). The
following standardization of specimen and attributes naming were implemented:
 Taxonomy
according
to
World
Register
of
Marine
Species
(WoRMS:
http://www.marinespecies.org).
 Habitat description according to Coastal and Marine Ecological Classification Standards
(CMECS: http://www.cmecscatalog.org)
 Parameter name; Unit; Device name; Developmental stage; Institution name; Country name;
Marine region - according to SeaDataNet Vocabularies (http://www.seadatanet.org/StandardsSoftware/Common-Vocabularies).
This system supports two types of data submission procedures, which support the above stated
data structure. The first is a downloadable excel file with drop-down fields based on the BOTS-DB
vocabularies. The file is filled and uploaded online by the data contributor. Alternatively, the same
dataset can be assembled by filling online forms and then submitted to the DB. Online access to
the BOTS-DB is under development. It will include interactive geographical map interface where
data may be queried, analyzed and downloaded.
MAGMATIC HOTSPOTS DRIVE UP P AMOUNT IN SAHARA DUST AND NOURISH
THE ATLANTIC AND THE AMAZON
Avner. Gross1, T. Goren1, C. Pio2, J. Cardoso2, O. Tirosh1, Y. Erel1, M.C. Todd3, D. Rosenfeld1, T.
Weiner1 D. Custódio2 and Alon Angert1
1
The Institute of Earth Sciences, The Hebrew University of Jerusalem, Israel [email protected]
CEASM & Department of Environment, University of Aviero, Portugal.
3
School of Global Studies, University of Sussex, Brighton, UK.
2
Millions of tons of dust particles are eroded every year from the Sahara desert soils and are
blown over the Atlantic Ocean and as far as the Amazon basin. This dust flux provides an input of
phosphorus (P) to the oligotrophic waters of the Atlantic Ocean and the P depleted rain forest of
America. Unlike nitrogen, P cannot be fixed from the atmosphere. Thus, the dust is an important
P source to oceans, which are responsible for a considerable fraction of the global net primary
productivity and CO2 sequestration. However, remarkably little data exist on the concentrations,
biological availability and active sources of Saharan dust-P during dust events over the Atlantic.
This lack of data means that the sensitivity of this P-limited ecosystem to Saharan dust-P
deposition is not well established. Here we report the characteristic of dust-P collected during all
the major events of 2011 over the Eastern Atlantic. We found that the dust contains remarkably
high concentrations of
bioavailable-P (~900 µg soluble-P g-dust-1 on average), up to 20 times
higher than previously assumed. From analysis of phosphate oxygen isotopes signatures
supported by remote-sensing imagery, we infer that the high concentrations result from dust
arriving from P-rich magmatic hotspots. We estimate that a single dust event can potentially
increase the mixed-layer bioavailable-P by ~30%, sufficient for an immediate effect on
spring/winter Atlantic phytoplankton bloom and also increase by ~8% the typical Amazon forest
soil stock of immediately-available-P. We also found that phosphate from the Bodélé depression,
considered to be the largest source of Saharan dust, has a unique isotopic signature which is not
evident in Cape-Verde but can be used in the future to identify this source. Our results provide
new information on bioavailable-P for experimental and modeling studies of oceanic
biogeochemical cycles.
CHALLENGES IN MODELING PROCHLOROCOCCUS WITH THE CLASSIC DROOP
FORMULATION – LIMITATIONS AND SENSITIVITY
Michal Grossowicz1, Dalit Roth-Rosenberg1, Dikla Aharonovich1, Michael J. Follows2 and Daniel
Sher1
1
Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Israel
[email protected], [email protected]
2
Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology,
Cambridge, MA, USA
Understanding the dynamics of complex microbial communities in nature requires mathematical
models, which typically are first built and tested on laboratory cultures. More importantly,
mathematical models help highlight gaps in understanding and identify future experimental
approaches. Here, we apply a classic internal stores (Droop/Caperon) model to study the
dynamics of Prochlorococcus, a globally abundant marine primary producer, in laboratory batch
culture. While the model reproduces well the initial, growth phase of Prochlorococcus cultures, it
fails to recapitulate the dynamics as the cultures approach steady state and decline. Several
processes, which are not well represented in the current model structure, may contribute to
these shortcomings, including excretion, mortality, the ratio of labile to refractory cellular material
and the potential for self-inhibition at high cell densities. We present an approach to
systematically identify model parameters which strongly affect different measurements (variables)
of model outcome, thus highlighting phytoplankton traits which are under-studied and for which
concerted experimental studies may provide important data for better modeling.
CIRCADIAN CLOCKS AND SCLERACTINIAN CORAL MECHANISM –
A BROAD REVIEW
Eldad Gutner-Hoch1, Aldo Shemesh 2 and Oren Levy1
1
The mina and Everard Goodman Faculty of Life Science, Bar-Ilan University, 52900 Ramat-Gan, Israel
[email protected]
2
Department of Environmental Sciences and Energy Reseach, Weizmann Institute of Science, P.O.Box 26,
76100 Rehovot , Israel
Scleractinian corals exhibit calcification dynamics with a cyclic pattern that correlates with
ambient light photoperiodicity. The common hypothesis regarding the phenomenon of
calcification dependency with light intensities is that the calcification process is being mediated by
the coral algal endosymbionts performances. Indeed several studies have demonstrated that the
algae photosynthesis contributes to the calcification process so calcification enhances as
photosynthesis increases. In recent years several studies have revealed the presence of circadian
clock components in scleractinian corals, such as blue-photoreceptors (cryptochromes), light
sensitive membrane receptors (opsins) and evidence for gene group clustering according to a
diurnal expression pattern. The presented study demonstrates with a range of experimental
evidences: calcification and photosynthesis rates, skeletal growth and gene expression profiles,
that Scleractinian corals most likely have an endogenous clock mechanism that control the
calcification cyclic rhythmicity. These evidences contribute remarkably to the insights of the coral
calcification process, a physiology process of an animal that affect the marine ecological wealth,
the past environment reconstruction and the basis for economically natural resources.
LESSONS LEARNED FROM COMPARISON OF CLIMATE CHANGE IMPACTS ON
LEVENT AND BALTIC BENTHIC COMMUNITIES
Tamar Guy-Haim1,2, Stephanie Sokol3, Martin Wahl3, Jack Silverman1 and Gil Rilov1
1
Israel Oceanographic and Limnological Research, National Institute of Oceanography, P.O. Box 8030, Haifa
31080, Israel [email protected]
2
Marine Biology Department, The Leon H.Charney School of Marine Sciences, University of Haifa, Mt.
Carmel, Haifa 31905, Israel
3
GEOMAR, Helmholtz Zentrum für Ozeanforschung, Benthosökologie, Düsternbrooker Weg 20, Kiel 24105,
Germany
The susceptibility of an organism to adverse environmental changes can be related to the range
of natural fluctuations in environmental conditions it experiences. In the coastal Levant (Eastern
Mediterranean), both temperature and pH conditions are diurnally and seasonally relatively stable
compared to coastal Baltic conditions. We hypothesized that Baltic species, required to endure
frequent and strong environmental fluctuations, had been pre-selected to better tolerate, or
adapt to, climate change. Thus, we expected a generally wider ecological tolerance in Baltic
species and a reduced sensitivity to the predicted changes in temperature and acidity as
compared to native Levant species. To examine this hypothesis, we tested the metabolic
responses of six benthic species from the Levant and Baltic subtidal zones to a wide range of
short term temperature treatments. These species were chosen because of their relative
abundance and their similar ecological functioning. Parallel experiments in Haifa, Israel and Kiel,
Germany were conducted using designated microcosm systems. The metabolic performance
measurements included rates of photosynthesis, respiration, calcification, consumption and
digestion. Our current findings indicate a wider tolerance range in the Baltic relative to the Levant
species in support of our hypothesis. For example, the photosynthetic rate of the abundant
Levant brown algae Cystoseira squarrosa (Fucaceae) decreased significantly at temperatures
higher than 29°C, which was the peak summer temperature in Israeli coastal waters 2-3 decades
ago. In contrast, in the abundant Baltic brown algae Fucus vesiculosus (Fucaceae) did not
present any declining trend in photosynthesis even well above the present summer temperatures.
This difference in species sensitivity has been observed in nearly all of our experiments. These
results suggest that many Levant native species may be at or close to their physiological tipping
point already at present peak summer temperatures (~31°C). Therefore, it is very likely that
further warming may irrevocably harm them and facilitate a major biotic shift of marine species in
the subtidal benthic communities along the coast of Israel and perhaps the entire Levant basin.
MORPHOLOGY, PHYLOGENY, AND SPECIES BOUNDARIES OF THE GENUS
OVABUNDA (OCTOCORALLIA, ALCYONACEA, XENIIDAE) OF THE RED SEA
Anna Halász1, Catherine S. McFadden2, Robert Toonen3 and Yehuda Benayahu1
1
Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv
69978, Israel [email protected] ; [email protected]
2
Department of Biology, Harvey Mudd College, 1250 N. Dartmouth Ave., Claremont, CA 91711, USA
[email protected]
3
Hawai’i Institute of Marine Biology, University of Hawaii at Manoa, 46-007 Lilipuna Road, Kane’ohe, HI
96744, USA [email protected]
Opportunistic and common xeniids are taking over degraded reefs and artificial reefs as well as
invading healthy, natural reefs. However, taxonomic difficulties and difficulty of identification in
the field have forced researchers to recognize them overall as a family, which precludes a detailed
understanding of the reef environment and the processes occurring at the genus and species
level. The genus Ovabunda Alderslade, 2001 is among the most common genera of the Red Sea
xeniids, along with Xenia Lamarck, 1816. Our research focused on Ovabunda and a two-step
approach was taken: an examination of type material, which led to a comprehensive taxonomic
revision of this genus; followed by an analysis of freshly collected Ovabunda colonies from Eilat.
We analyzed these colonies using four molecular markers (mtMutS, ND2, COI, and 28S) and
examined the morphological characters used in the revision. We concluded that the collected
material presents a continuum in the morphological characters used for species description. The
genetic analysis revealed two groups, one of which is well supported. These groups are
characterized by pulsating or non-pulsating colonies, respectively. No other morphological
character corresponds to the two groups. This finding – the existence of two major phylogenetic
groups that can be distinguished even in the field by means of a clear trait – led us to ask
whether they are reproductively isolated. Examination of parent and respective offspring genetic
affiliation (using 28S) revealed that they are most likely isolated, representing at least one "real"
species with pulsating colonies, and a complex of non-pulsating colonies that is yet to be
resolved. This kind of research combining morphological, molecular, and reproductive studies may
lead to a better understanding of the xeniid community in Eilat and in other areas, and facilitate
future ecological studies.
‫תופעת 'תרדמת החורף' באיצטלן המושבתי ‪Botrylloides leachi‬‬
‫יוסי חיימס ובוקי רינקביץ'‬
‫המכון לחקר ימים ואגמים חיפה‬
‫אורגניזמים חד ורב תאיים רבים התפתחו בסביבה אשר בה הם יכולים להתקיים רק בחלק מעונות‬
‫השנה‪ .‬בזמנים בהם תנאי הסביבה הופכים לבלתי שרידים‪ ,‬צורות חיים שונות מצאו דרכי פעולה‬
‫שונים להתמודדות כנגד תנאי הסביבה המועדים לפורענות באמצעות הורדה משמעותית של‬
‫מטבוליזם וכניסה למצב של חוסר פעילות המתויק כמצג תרדמה‪ .‬האיצטלן בוטריל שידרני (ב"ש)‬
‫‪ Botrylloides leachi‬הינו איצטלן ישיב השייך לתת מערכת מיתרני הזנב (‪ )Urochordata‬במערכת‬
‫המיתרנים (‪ )Chordata‬וניזון מחומרים אורגנים אותם הוא מסנן ממי הים‪ .‬מושבת ב"ש מורכבת‬
‫ממספר יחידות (עד אלפי יחידות) זהות גנטית הנקראות זואידים‪ .‬זואידי המושבה המהווים את‬
‫היחידות המודולריות של המושבה‪ ,‬אחראיים על תזונה‪ ,‬נשימה‪ ,‬חילוף חומרים ורביית המושבה‪,‬‬
‫כאשר הם מחוברים בניהם במערכת דם מרושתת המחברת בין כל חלקי המושבה‪ .‬מבנה זה של‬
‫מושבת ב"ש אופייני לחודשי האביב והקיץ ומשתנה כאשר טמפ' מי הים מתקררת משמעותית‬
‫בחודשי החורף‪ .‬ירידת טמפ' מי הים מובילה את המושבה לתצורה של 'תרדמת חורף'‪ ,‬הכוללת‬
‫ספיגת כל הזואידים המסננים והשארת מטווה בלתי סדור של צינורות דם המכילים תאי דם צפופים‪,‬‬
‫החומר הביולוגי היחידי שנשאר לאורך תקופת החורף‪ .‬עם תום תקופת החורף ועליית טמפרטורת מי‬
‫הים‪ ,‬צבר כלי הדם "מתעורר" לחיים וממנו מתפתחים בתהליך רגנרציה מואץ זואידים חדשים‬
‫ומושבה מחודשת‪.‬‬
‫תהליך 'תרדמת החורף' בב"ש המתחיל בספיגה והעלמות כל יחידות המושבה הפונקציונאליות‪,‬‬
‫ממשיך בשמירה על רקמת כלי הדם במצב סטאטי למספר חודשים ומסתיים בתהליך רגנרציה‬
‫מכלי דם‪ ,‬הינו דפוס ייחודי של התחדשות במערכת המיתרניים‪ .‬מחקר זה עוסק בהבנת תופעת‬
‫התרדמה בב"ש ובוחן אותה ברמה המורפולוגית‪ ,‬התאית והמולקולארית‪ .‬תוצאות המחקר מראות‬
‫שהתהליך מתרחש בפרק זמן של ‪ ,-41‬יום תוך כדי מעבר מספר שלבים מורפולוגיים והיסטולוגים‪:‬‬
‫ירידה משמעותית בשטח המושבה עד ‪ ,1‬אחוז מגודלה המקורי‪ ,‬ירידה משמעותית בקצב זרימת‬
‫הדם‪ ,‬הופעת צברי תאים רב גרעיניים בחלל צינורות הדם אשר מספרם עולה משמעותית עם כניסת‬
‫המושבות להיברנציה‪ ,‬יצירת מוקדי התחדשות בכלי הדם‪ ,‬הופעה ספונטנית של תאי דם המבטאים‬
‫גנים המוכרים כסמנים לתאי גזע ועלייה במספר תאי הגזע במושבות הנמצאות בהתחדשות‪.‬‬
STRATIFIED SHEAR FLOW INSTABILITY ARISING FROM INTERACTING
VORTICITY WAVES
Eyal Heifetz
Tel Aviv University, [email protected]
Stably stratified shear flow instability is an essential mechanism in generating ocean waves and
mixing. Here we present a dynamical interpretation for the instability mechanism in terms of
interaction at a distance between counter propagating vorticity waves. This generalizes the
familiar large scale potential vorticity Rossby wave approach to baroclinic instability to interaction
between other types of vorticity waves. The latter may be gravity and capillary vorticity waves in
the presence of stable stratification and in the interface between immiscible fluids. Applying
vorticity inversion, the 2D shear instability dynamics is formulated solely in terms of the spanwise vorticity and the normal displacement across the shear. The action at a distance mechanism
then explains the counter-intuitive phenomena of how the presence of stable stratification
destabilizes the shear. Potential application for wind-generated wave mechanisms and
thermocline mixing will be discussed.
RECONSTRUCTING THE SHORELINE AND CLIMATE OF THE ANCIENT MAYA
PORT VISTA ALEGRE USING MARINE GEOARCHAEOLOGICAL METHODS
Jaijel R.1,Goodman B.1,Ben Avraham Z.1, Glover J.2 ,Beddows P.3 ,Carter A.3 ,Smith D.4 and
Rissolo D.5
1
Leon Charney School of Marine Sciences, University of Haifa [email protected]
Department of Anthropology, Georgia State University [email protected]
2
3
Department of Earth Sciences, Northwestern University [email protected]
Department of Biology, University of Washington [email protected]
5
Waitt Institute, California, USA [email protected]
4
The environmental and morphological history of the ancient Maya port site of Vista Alegre,
located along the north coast of Mexico's Yucatan Peninsula, is being investigated within a larger
multidisciplinary effort called the Costa Escondida Project. The projects main goals are to learn
how the ancient inhabitants adapted to the environment, and to understand how this coastal site
was integrated into broader maritime trade routes. The portion of the research that will be
presented concentrates on the sites geomorphology and climate during the past 2-3000 years
through a multiproxy analysis of core and surface samples. This study aids our understanding of
the site's possible functions, the environmental challenges the local inhabits contended with, and
possible ancient harboring locations. Results from the research may make it possible to recognize
hurricane proxies in the sediment, locate underwater manmade seafaring artifacts and facilities,
determine the range of economic opportunities for past inhabitants and quantify the availability of
potable water sources.
MEASURING CONTINUES CAMOUFLAGE BEHAVIOUR
Noam Josef and Nadav Shashar
1
Department of Life Sciences, Eilat Campus, Ben-Gurion University of the Negev, Beer Sheva, 84105, Israel
[email protected]
2
H. Steinitz Marine Biology Laboratory, Inter-university Institute for Marine Sciences, P.O.B. 469, Eilat
88103, Israel
In the visual system of many animals, Movement of a target attracts one’s attention and allows
rapid figure–ground segregation even when the texture of the target and background match
perfectly (Julesz 1971; Srinivasan et al. 1990; Frost 1993; Smith and Snowden 1994). Animals
that rely on camouflage may minimize visible movement through strategies such as stealth and
deceptive resemblance (Cott 1940), but often this is not possible and many will decide to stay
motionless as much as possible. Any camouflaging animal dealing with the question whether to
run or stay motionless, obscure a premise: camouflage is harder while moving.
How then do animals reduce the risk of predation as they move?
Cephalopod, particularly benthic species of cuttlefish and octopus are masters of adaptive
camouflage. These animals may change their body coloration and skin texture to match a given
environment mostly by neurally controlled chromatophores (Hanlon and Messenger 1996). It is
long known that cephalopods change their appearance when they move, presumably to avoid
detection during or after the movement. For example, octopus uses a combination of stealth and
rapid chromatic and textural changes as they move, apparently to match the changing
background (Hanlon et al. 1999) and cuttlefish showed context-dependent body pattern use
during motion (Zylinski et al., 2009). In our latest study we use the capacity for rapid pattern
change in the cuttlefish Sepia officinalis to investigate the potential for motion camouflage by an
animal that can alter its body pattern in less than a second (Hanlon and Messenger 1996). We
assessed changes in body intensity during movement over a periodic stimuli (uniform grey and
black patterns), which is known to evoke colour matching with respect to substrate intensity. On
a more detailed aspect, we measured all motion properties of a given animal while sampling its
body colour, allowing us to reveal some of the tactics these animals use to keep as less
conspicuous as possible while they are moving. The main subject that i would like to present is
the video analysis code we developed in the Matlab environment and the graphical presentation
of our results. We thank you in advance for giving us the opportunity to present our and learn
others in our ever-growing field of behavioral sciences.
DISTURBANCE OF SMALL PHYTOPLANKTON SPECIES IN LAKE KINNERET
Yury Kamenir and Zvy Dubinsky
The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel
[email protected] , [email protected]
Disturbances of aquatic ecosystems, caused by both anthropogenic impacts and climatic changes,
may cause distinct transformations in natural communities. Some of these changes, especially
those connected with the water quality degradation, can be undesirable or even dangerous.
Ecological management and forecast demand quantitative estimators and models for diagnostics
of aquatic assemblage structural changes. The phytoplankton assemblage studied during a longterm monitoring of Lake Kinneret demonstrated the existence of consistent species abundance
distributions (SAD). Sometimes SAD pattern changes were notable during periods of prominent
changes of the phytoplankton annual succession. The species list variations are notable even
during stable periods. Due to size structure similarity analyses of individual species, phyla and
integral phytoplankton assemblage, the phylum looks as an intermediate level of optimal
sensitivity. Some phyla look suitable for the aims of phytoplankton structural-similarity
estimation. In Lake Kinneret, Cyanophyta demonstrate especially high sensitivity. The rankabundance distributions (RAD) of species demonstrated pronounced differences between the
taxonomically rich central region producing the reliable RAD backbone and extremely variable
tails of a few species. The RAD pattern comparisons enhance the diagnostic importance of smallcell species. A simple aquatic community disturbance index was constructed on the base of smallcelled species.
ON-LAND AND OFFSHORE EVIDENCE FOR HOLOCENE EARTHQUAKES IN THE
NORTHERN GULF OF AQABA-EILAT
Kanari M.1,3, Bookman R.2, Ben-Avraham Z.1,2, Tibor G.3, Niemi T.M.4, Goodman Tchernov
B.N.2,5, Wechsler, N.1 and Marco S.1
1
Dept. of Geophysical, Atmospheric and Planetary Sciences, Tel-Aviv University, Tel-Aviv, Israel
The Dr. Moses Strauss Department of Marine Geosciences, Leon H.Charney School of Marine Sciences,
Haifa University, Mt. Carmel, Haifa 31905, Israel
3
Israel Oceanographic and Limnological Research Ltd., Tel-Shikmona, P.O.Box 8030, Haifa 31080, Israel
4
Dept. of Geosciences, University of Missouri-Kansas City, U.S.A.
5
Interuniversity Institute for Marine Sciences, Eilat 88103, Israel
2
The aim of this ongoing research is to study the Holocene tectonic and sedimentary evolution of
the Northern Gulf of Aqaba-Eilat (NGAE) by correlating new on-land and offshore seismic and
sedimentary data, and by identifying and dating seismic activity. The on-land continuation of the
submarine Avrona Fault was located and dated in a paleoseismic trench; marine sediment cores
retrieved from the NGAE were profiled for grain size, demonstrating discrete anomalies
suggested as representing sediment reworking events. 14C age constraints of the on-land fault
(trench T3) and grain size anomalies in the offshore core P27 (530 mbsl) coincide with the
historically documented earthquake which caused the destruction of Aqaba in 1068 AD. Following
the grain size anomaly pattern of P27, we further suggest that other grain size anomalies in the
same core, as well as in other cores from the deep basin, possibly represent sediment reworking
from mass-flow triggered by earthquakes. The 14C age models of cores P27 and P22 (320 mbsl)
yield sedimentation rates for the deep basin on the NGAE, varying between 0.2-0.4 mm/yr in the
mid- to late Holocene; a higher sedimentation rate of about 0.6 mm/yr is observed in the very
early Holocene (~12 ka). Further dating of cores from across the NGAE (currently in progress) is
expected to yield a correlation of dated grain size anomalies across cores. This would serve to
validate the tectonic/seismic origin of the sediment reworking events which they represent,
versus local sediment disturbances (e.g. sporadic slumping), enabling us to date Holocene
seismic events in the core sediments.
ACOUSTIC REMOTE SENSING OF SPATIO-TEMPORAL DYNAMICS OF
INTERNAL WAVES IN A STRATIFIED LAKE
Boris Katsnelson1, Andrey Lunkov2 and Ilia Ostrovsky3
1
L. Charney School of Marine Sciences, University of Haifa, Mount Carmel 31905, Israel
[email protected]
2
Wave Research Center, A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, 38
Vavilova str., Moscow 119991, Russia [email protected]
3
Israel Oceanographic and Limnological Research, Yigal Alon Kinneret Limnological Laboratory, POB. 447,
Migdal 14950, Israel [email protected]
In stratified lakes internal waves have great ecological significance, since they induce mixing and
resuspension and material transport at the lake periphery, affecting chemical regime and
ecosystem productivity. Reconstruction of the spatiotemporal dynamics of the basin-scale internal
waves and their accurate parameterization are important tasks. In this paper, usage acoustic
methodology is suggested for the parameterization of the basin-scale internal waves. It is shown
the effect of internal Kelvin waves (IKWs) on spatiotemporal variability of the mid-frequency (1
kHz) sound field in a deep stratified lake using acoustic modeling. The IKWs cause significant
fluctuations of the sound field, such as a horizontal shift of interference structure or frequency
shift in spectrum at single receiver. This shifts can be easily measured in situ and used for
reconstruction of IKW parameters. Overall, authors suggest implementing the low-cost acoustic
methodology for an accurate parameterization of the basin-scale internal waves and studying
their dynamics.
‫שימוש בצילום וידאו תת‪-‬מימי‪ ,‬תלת‪-‬מימדי‪ ,‬לכימות השונות המורפולוגית במנגנון‬
‫שאיבת הטרף בדגי שונית‬
‫‪1,2‬‬
‫טל קרן‪ 1,2‬ורועי הולצמן‬
‫‪1‬המחלקה לזואולוגיה‪ ,‬הפקולטה למדעי החיים‪ ,‬אוניברסיטת תל אביב ‪0,,7211‬‬
‫‪4‬המכון הבינאוניברסיטאי למדעי הים באילת‪ ,‬אילת ‪2211,‬‬
‫‪[email protected], [email protected]‬‬
‫הקשר בין מבנה ותפקוד עומד בבסיסן של שאלות במחקר האבולוציוני‪ .‬במסגרת הניסיון לעמוד‬
‫על טיבו של הקשר בין שונות מורפולוגית ושונות תפקודית בכוונתנו לאפיין את השונות המורפולוגית‬
‫במנגנון האכילה של אוכלוסיית דגים‪ .‬לצורך כך נשתמש במערכת של מצלמות וידאו על מנת‬
‫לתעד דגים ממין כרומית ירקרקת )‪ (Chromis viridis‬מבצעים שאיבת טרף )‪(suction feeding‬‬
‫בסביבתם הטבעית – שונית האלמוגים במפרץ אילת‪ .‬מערכת המצלמות ממוקמת בשונית במרחק‬
‫של כמטר וחצי מאלמוג מעונף‪ ,‬המאוכלס על ידי להקת כרומיות‪ .‬שתי המצלמות מכוונות לנפח‬
‫המים הסמוך לאלמוג כך שדג השוחה בנפח זה (כ‪ 11x01x41 -‬ס"מ) נקלט על ידי שתי המצלמות‬
‫משתי זוויות שונות‪ ,‬ומיקומו מתורגם לאינפורמציה תלת‪-‬מימדית‪ .‬המצלמות מקליטות במהירות של‬
‫‪ 411‬פריימים לשנייה וברזולוציה של ‪ 1421x1142‬פיקסלים‪ .‬ברזולוציה ובמהירות זו‪ ,‬המצלמות‬
‫מסוגלות להקליט כ‪ ,-‬שניות של וידאו‪ .‬זמן זה הוא די והותר‪ ,‬שכן אירוע טריפה נמשך פחות מ‪111 -‬‬
‫אלפיות השנייה‪ .‬המצלמות מחוברות דרך כבל רשת‪ ,‬שאורכו כ‪ 141 -‬מ'‪ ,‬למחשב במעבדה‪ ,‬כך‬
‫שניתן לצפות בקטעי הוידאו בזמן אמת‪ ,‬ולשמור אותם בזיכרון המחשב‪ .‬קטעי הוידאו עוברים אנליזה‬
‫בתכנת ‪ MATLAB‬באמצעות התוסף ‪ .DLTdv5‬השלב הראשון בתהליך האנליזה הוא כיול המערכת על‬
‫ידי צילום של אובייקט תלת‪-‬מימדי עליו מסומנות נקודות במיקומים ידועים‪ ,‬וניתוח התמונות בתכנת‬
‫‪ MATLAB‬באמצעות התוסף ‪ .DLTcal5‬התוצר של שלב הכיול הוא מערכת צירים תלת‪-‬מימדית‪.‬‬
‫בשלבי הניתוח של הסרטים‪ ,‬מסומנת נקודות ציון ספציפיות על גוף הדג בכל פריים ופריים בקטע‬
‫הוידאו‪ ,‬בשתי המצלמות‪ .‬נקודות הציון המסומנות מיוחסות למערכת הצירים שהתקבלה משלב‬
‫הכיול‪ ,‬ומיקומן מוגדר באמצעות קואורדינטות על מערכת צירים זו‪ ,‬בדיוק הגבוה מ‪ .,4% -‬מתוך‬
‫מיקומי הנקודות ניתן לחשב מרחקים‪ ,‬וביחס לציר הזמן של סרט הוידאו ניתן לחשב מהירויות‪ .‬כך‬
‫למשל‪ ,‬על ידי סימון השפה העליונה והשפה התחתונה של הדג‪ ,‬ניתן לחשב את גודל פה הדג‬
‫ומהירות פתיחתו‪ ,‬וכן תכונות מורפולוגיות וקינמטיות אחרות‪ .‬לאחר דיגום אוכלוסיות האלמוגיות‬
‫בשונית והערכת השונות המורפולוגית במספר תכונות המעורבות במנגנון האכילה‪ ,‬נשתמש במודל‬
‫מכניסטי להערכת החשיבות של כל אחת מהתכונות להצלחת הטריפה‪ ,‬ונתאר את הקשר בין‬
‫השונות במורפולוגיה של כל תכונה לתפקידה במנגנון האכילה‪.‬‬
‫השפעת שינויי טמפרטורה על מטבוליזם ושרידות של החלזונות‬
‫‪ Phorcus turbinatus‬ו‪Phorcus articulatus -‬‬
‫ליאור קליין‪ ,1‬צבי דובינסקי‪ ,1‬תמר גיא‪-‬חיים‪ ,2‬דוד אילוז‪ 1‬וגיל רילוב‬
‫‪,2‬‬
‫‪1‬הפקולטה למדעי החיים ע"ש מינה ואררד גודמן אוניברסיטת בר אילן רמת גן‬
‫‪44,1114 [email protected] , [email protected]‬‬
‫‪ 4 [email protected]‬בית הספר למדעי הים ע"ש לאון צ'רני‪ ,‬אוניברסיטת חיפה‪ ,‬הר הכרמל‬
‫‪,2,22,2‬‬
‫‪,[email protected]‬המכון לחקר ימים ואגמים תל שקמונה ת"ד ‪ ,21,1‬חיפה‬
‫‪[email protected] ,‬‬
‫בעקבות שינויי האקלים הגלובלי‪ ,‬קיימת חשיבות לבחינת סבילותם של יצורים בעלי חשיבות‬
‫אקולוגית‪ ,‬בכדי שניתן יהיה לחזות את ההשלכות האקולוגיות של שינויי האקלים במערכות שונות‪.‬‬
‫על טבלאות הגידוד‪ ,‬באיזור הכרית שלאורך חופי ישראל‪ ,‬נפוצים מספר מיני בעלי חיים שלהם‬
‫חשיבות אקולוגית בשל פעילות הרעייה שלהם‪ .‬חד שן משובץ‪ Phorcus turbinatus ,‬וחד שן מנומר‪,‬‬
‫‪ ,)Trochidae, Gastropoda( Phorcus articulatus‬הינם מהרועים הנפוצים ממערכת הרכיכות‪ .‬למינים‬
‫אלו תפוצה ים‪-‬תיכונית‪ ,‬כאשר את ‪ P. articulatus‬ניתן למצוא רק באיזורים דמויי לגונה‪ .‬איזור הכרית‬
‫מאופיין בשינויים קיצוניים בטמפרטורה‪ ,‬מליחות וחמצן‪ ,‬ובעת תנאי יובש חלזונות אלו מוצאים‬
‫מסתור בנישות שונות מתחת למים ולעיתים חשופים לטמפרטורות מים גבוהות‪ .‬מטרת מחקר זה היא‬
‫לבדוק כיצד טמפרטורת מים משפיעה על שרידות ומטבוליזם של שני מינים אלו‪ .‬כשלושים פרטים‬
‫מכל מין נאספו מטבלת הגידוד בשיקמונה‪ .‬הפרטים הושמו במערכת של ‪ 11‬אקווריומים השולטת‬
‫על רמת הטמפרטורה בצינצנות ניסוי על‪-‬ידי בקרה אלקטרונית‪ ,‬בתנאי אור טבעי‪ .‬לאחר אקלימציה‬
‫איטית נחשפו החלזונות ל‪ 11 -‬טמפרטורות שונות בין ‪ 14-,4°C‬מעלות‪ ,‬כאשר טמפרטורת המינימום‬
‫דומה לזו ששררה בחורפים לפני ‪ 41-,1‬שנים‪ ,‬וטמפרטורת המקסימום מדמה ערכים החזויים על פי‬
‫ה‪ .IPCC -‬במהלך ארבע שבועות עקבנו אחר השרידות וקצב הנשימה (מדידת חמצן מוסס‬
‫באינקובציות בתחילת‪ ,‬אמצע וסוף הניסוי) כמדד לתפקוד הפיזיולוגי של החילזון‪ .‬שני המינים מתו‬
‫בטמפרטורות של ‪ ,4°C‬ו‪ ,,,°C -‬אולם ב‪ P. turbinatus-‬נצפתה גם תמותה ב ‪( ,1°C‬טמפרטורות קיץ‬
‫כיום) ואף ב‪ .4,°C -‬בשני המינים נראתה עלייה בקצב הנשימה עם העלייה בטמפרטורה‪ .‬ב‪P. -‬‬
‫‪ turbinatus‬נמצאה קורולציה בין מסת הגוף לקצב המטאבולי הספציפי (‪,)Specific metabolic rate‬‬
‫אך לא לקצב המטאבולי (‪ .)Metabolic rate‬לעומת זאת‪ ,‬ב‪ P. articulatus-‬נראתה קורלציה בין מסת‬
‫הגוף לקצב המטאבולי ולא לקצב המטאבולי הספציפי‪ .‬תוצאות אלו מראות כי בין שני המינים ישנו‬
‫שוני בפיזיולוגיה (צריכת החמצן) ובשרידות בתגובה לטמפרטורה‪ ,‬ולפיכך כנראה גם במידת‬
‫רגישותם לשינויי טמפרטורה הנובעים משינוי האקלים הגלובלי‪.‬‬
‫איפיון דינאמיקה של מערכות פלאנקטוניות מניתוח רב שכבתי של נתוני לויין‬
‫יואב להן‪ ,‬אילן קורן ואסף ורדי‬
‫המחלקה למדעי כדור הארץ‪ ,‬מכון וייצמן למדע‬
‫‪[email protected] ,[email protected] ,[email protected]‬‬
‫פריחות של פיטופלנקטון ‪ -‬אורגניזם פוטוסינטתי שאחראי למחצית מהיצרנות הגלובאלית של חומר‬
‫אורגני – מהוות גורם חשוב בקביעת שטף הפחמן בין האטמוספירה לים‪ .‬מזה כשלושה עשורים‪,‬‬
‫חלק ניכר מהמחקר של פריחות פיטופלנקטון מבוסס על נתוני לוויין שמספקים תצפיות סינופטיות‬
‫על הסביבה הביולוגית הימית‪ .‬מעצם טיבם נתוני הלויין מספקים תמונות מצב רגעיות‪ .‬דבר זה‬
‫מגביל את היכולת לניטור תהליכים פנימיים במערכות פלנקטוניות אשר מוסעות ומעורבבות על ידי‬
‫זרמי פני השטח‪ ,‬ומקטין את יכולתנו להעריך את השפעת הפריחות על מחזור הפחמן‪.‬‬
‫בעבודה זאת נסקור את האפשרות לניתוח נתוני לווין בגישה לגראנג'יאנית אשר מבוססת על מעקב‬
‫ואפיון גבולות המערכת הפלאנקטונית במהלך חייה‪ .‬גישה זו מאפשרת כימות של התהליכים‬
‫הפנימיים והסביבתיים המשפיעים על המערכת‪ .‬הגישה מבוססת על שילוב של נתוני צבע ים‬
‫המספקים מידע על המערכת הפלנקטונית עם נתוני אלטימטריה המספקים מידע על שדה הזרימה‪.‬‬
‫יישימותה של הגישה הלגרנאג'יאנית ויתרונותיה וחסרונותיה בהשוואה לניתוח סטנדרטי של נתוני‬
‫לויין יידונו בהקשר של מספר מקרי מבחן מהים התיכון ומהאוקיינוס האטלנטי‪.‬‬
THE ROLE OF PARASITIC CHYTRIDS IN THE AQUATIC FOOD WEB: EATING
THE INEDIBLE
Tamar Leshem1, Sharon Mecher1, Martha L Powell2, Peter Letcher2 and Assaf Sukenik1
1
Yigal Allon KinneretLimnological Laboratory (KLL) Israel Oceanographic andLimnological
Research (IOLR), P.O.B. 447, [email protected]
2
Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487
Chytrids are true zoosporic fungi that act as parasite or as saprobes of many organisms. In
aquatic habitats, many phytoplankton species are susceptible to parasitic chytrids that may
control their abundance and distribution. In Lake Kinneret, the bloom forming dinoflagellate is
infected by the chytrid Phlyctochytrium sp. Here we demonstrate how chytrid infecting large cells
of Peridinium, which are un eatable by zooplankton due to their size limitation, are transformed
into small size zoospores, which are easily consumed by zooplankton. First, we validated that the
zooplankter ceriodaphnia isolated from Lake Kinneret, readily consumed chytrid's zoospores.
Then we conduct feeding experiments in which ceriodaphnia fed on either Peridinium cells or
chytrids infected Peridinium. Result clearly showed that ceriodaphnia could grow only when the
peridinium was infected by chytrids as chytrids zoospores were observed in its gut. These results
support the current concept that phytoplankton infection by chytrids plays a duel role in the
aquatic ecosystem, nutrient recycling and trophic transformation via the so-called "Myco-loop".
COMPARING LIVE-DEAD MOLLUSCAN ASSEMBLAGES IN THE SHAFDAN AREA
OF THE MEDITERRANEAN SHELF AS A PROXY FOR HUMAN IMPACT
Yael Leshno1,2, Yael Edelman-Furstenberg2 and Chaim Benjamini1
1
Department of Geological and Environmental Science, Ben Gurion University of the Negev, Beer Sheva
84105, Israel
2
Geological Survey of Israel, 30 Malkhe Israel, Jerusalem 95501, Israel
[email protected], [email protected], [email protected]
Shelled mollusks are sensitive indicators of seafloor health conditions. This study aims at testing
for match or mismatch in the coastal community structure of modern (sediment-top) death
assemblages vs. live-collected mollusk assemblages, from a polluted (sewage outfall) and control
sites, off Israel’s coast. Multivariate analysis shows significant differences between live and dead
assemblages of all samples, with live assemblages clustered into two seasons- winter and
summer. Temperature profiles show that strong storms in late fall caused early mixing of the
water column, creating only two seasons- summer and winter. The storms dispersed the sludge
accumulated on the seafloor. This may account for the lack of difference between the control and
polluted sites, and the similarity within the live and dead assemblages across habitats. Fidelity of
live to dead assemblage is very high; all species found live were also found dead. Assemblages
are dominated by the bivalve Corbula gibba, which accounts for 20-30% of all individuals. Livedead comparison of taxonomic composition, in both stations, shows decline abundance of
suspension-feeders and rise of deposit-feeders, mainly the bivalves Nuculana pella and Nucula
nitidosa.
SPATIAL AND TEMPORAL DYNAMICS OF BACTERIAL BIOFILM COMMUNITIES
ALONG THE PROCESSING PATHWAY IN A LARGE-SCALE SEAWATER REVERSE
OSMOSIS DESALINATION PLANT
Adi Levi1, Edo Bar-Zeev1,2, Hila Elifantz1, Tom Berman3 and Ilana Berman Frank1
Bar Ilan University, Mina and Everard Goodman Faculty of Life Sciences, Ramat Gan, Israel [email protected]
Current address. Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut
06520-8286, United States
3
Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, P.O.B. 447, Migdal 14950, Israel
1
2
Biofouling impacts seawater reverse osmosis (SWRO) desalination plants by directly reducing
filtration efficiency, increasing energetic demands and incurring further costs. Here we examined
the spatial and temporal composition and dynamics of the bacterial communities along the
treatment stages of a large-scale SWRO facility as a first step to developing sustainable biofilm
reduction solutions. The bacterial community structure of both water samples and surfaceattached biofilm was followed annually by seasonal sampling at the ADOM desalination facility
(Ashkelon, Israel) in February, May, September and November 2011. Bacterial community
composition
throughout
the
desalination
facility
was
determined
by
16S
rRNA
454
pyrosequencing. Our results show that biofilm community within the rapid sand filtration (RSF),
micronic filters (MF) and reverse osmosis (RO) membranes were significantly different from the
intake water-sample populations. Moreover, surface biofilm samples significantly differed from
one another while the bacterial populations within the water samples were similar along the
treatment pathway. Proteobacteria- (water 80-90% and surface 40-60%) dominated all sampling
stations. RO biofilm community structure was closely related to the water samples with high
abundance of Alphaproteobacteria SAR11 cluster. The microbial communities on the RO shifted
from Alphaproteobacteria (winter and fall) to Gamaproteobacteria dominance (spring-summer),
primarily due to increased abundance of the moderate halophilic genus Kangiella combined with
a reduction in SAR11 cluster. RSF and MF samples had the highest Shannon diversity values
(5.06-5.95), while microbial diversity of the RO biofilm was much lower (2.27-3.91) resulting
from the hypersaline conditions, high pressure, and intense shear forces on the RO membrane.
The unique niche of the RO and its distinctive bacterial population reduce the chance for
successful proliferation of RSF or MF bacteria on to the RO membranes. Our results clarify the
dynamic interactions between the ambient source planktonic bacteria, biofilm development along
the pretreatment stages and the subsequent biofouling of RO membranes; thus, facilitating
future regulation of biofouling for desalination industries.
EVOLUTIONARY CONSERVATION OF OOGENESIS IN THE SEA ANEMONE
NEMATOSTELLA VECTENSIS
Levitan Shimrit1, Brekhman Vera1, Chalifa-Caspi Vered2, Ziv Tamar3, Markovich Gordon Michal2,
Admon Arie3, Lubzens Esther3 and Lotan Tamar1
1
The Leon H. Charney School of Marine Sciences, Marine Biology, University of Haifa, Haifa, Israel
[email protected] ; [email protected] ; [email protected]
2
Bioinformatics Core Facility, Ben-Gurion University of the Negev, Beer-Sheva, Israel
[email protected] ; [email protected]
3
Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
[email protected]; [email protected] ; [email protected]
Sexual reproduction involves the formation of mature oocytes with an ability to undergo
fertilization and subsequently develop into embryos. Transcriptome profiling has shown that most
genes expressed in oocytes are conserved among invertebrate and vertebrate species. Our study
aims at extending this general conclusion specifically to the oocyte proteome, by comparing the
oocytes of two widely diverse organisms thereby spanning ~500 million years of evolution. We
identified 1,837 proteins in mature ovulated oocytes of a basal metazoan, the cnidarian sea
anemone Nematostella vectensis and show their putative similarity to MII stage oocyte of a
mammalian species. Some of the identified proteins were associated with oocyte structure and
function, while others were germ-cell-specific proteins. In addition, vitellogenin was found to
constitute 67% of Nematostella egg yolk proteins. Further analyses using in situ hybridization
determined that the vitellogenin transcripts are localized within the putative ovarian tissue, in the
mesenterial somatic cells but not in the oocytes themselves. This study provides the first catalog
of cnidarian oocyte proteins, revealing highly conserved ancient organization of life processes and
offers an insight into an evolutionarily conserved basal oocyte template of eumetazoa. Future
comparisons of oocytes components between distinct bilaterian taxa and Nematostella as well as
other cnidarians will provide a better understanding of the mechanisms that led to the evolution
of embryogenesis. It suggests that the oocyte proteome template predates the divergence of
the cnidarian and bilaterian lineages and raises a question on its origin.
"FISHING FOR PLANKTON" STUDYING THE FEEDING MECHANISM IN
GROUPS OF PSEUDANTHIAS SQUAMIPINNIS
Yoav Lindemann1,2, Irina Kolesnikov1, Lior Baltiansky3 and Amatzia Genin1,3
1
The Interuniversity Institute for Marine Sciences, POB 469, 88103 Eilat, Israel.
The Fredy and Nadine Herrmann Institute of Earth Sciences, the Hebrew University of Jerusalem,
Jerusalem 91904, Israel.
3
Department of Ecology, Evolution and Behavior, Silberman Institute of Life Sciences, the Hebrew University
of Jerusalem, Jerusalem 91904, Israel.
2
Zooplankton drifting from the open ocean towards coral reefs is a valuable source of nutrients for
the coral reef community. Site attached zooplanktivorous fishes forage above the reef in fixed
locations and feed on this drifting food source. The digestion products of this predation are
excreted by fish and become available as dissolved nutrients. The effects of prey density, current
speed, and fish group size on zooplankton predation rates were measured in situ using a nontraditional method - a moored Bongo net, with the site attached zooplanktivorous fish
Pseudanthias squamipinnis. The results indicate strong effects of prey flux and group size on per
capita predation rates by the fish. The implications of our findings to the ecology of the fish the
biogeochemistry of the reef will be discussed.
A RENEWED LOOK AT IRON ACQUISITION STRATEGIES IN AQUATIC
CYANOBACTERIA
Hagar Lis1,2, Chana Kranzler2,3, Nir Keren3 and Yeala Shaked1,2
1
The Freddy and Nadine Herrmann Institute of Earth Sciences, Edmond J. Safra Campus, Givat Ram,
Hebrew University of Jerusalem, Israel [email protected]
2
Interuniversity Institute for Marine Sciences in Eilat, Israel
3
Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences,
Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Israel
Cyanobacteria are a diverse and highly successful group of organisms, prevalent throughout
aquatic ecosystems.
Due to their taxonomic ascription, these photosynthetic prokaryotes are
often associated with the siderophore mediated iron uptake strategy employed by heterotrophic
bacteria.
However, siderophore production is not well suited to dilute, heterogeneous ocean
environments in which diffusive losses pose significant challenges to this strategy. Moreover,
genetic studies show that open ocean cyanobacteria possess neither siderophore biosynthesis nor
siderophore transport genes – capabilities which seem to be limited to freshwater, brackish and
coastal environments. Recent studies uncovered an alternative high affinity iron uptake pathway
functioning in Fe-limited model cyanobacteria – reduction of Fe(III) species prior to transport
though the plasma membrane. In this contribution we examine the prevalence of this mechanism
amongst genetically and ecologically diverse cyanobacterial strains and across several Fesubstrates. Using short term iron uptake assays, we find that several cyanobacterial species apply
the reductive pathway during iron uptake. Some of these species are siderophore producers that
employ reduction only for specific Fe-compounds. Thus reductive iron uptake appears to be a
prevalent strategy amongst both fresh water and marine cyanobacteria in the uptake of various
Fe-substrates. These findings lend insight into the relationship between environmental pressures
and the evolution of cyanobacterial iron uptake strategies.
EFFECTS OF GLOBAL WARMING AND OCEAN ACIDIFICATION ON THE
MEDITERRANEAN CORAL BALANOPHYLLIA EUROPAEA COMPARING TO THE
TROPICAL CORAL STYLOPHORA PISTILLATA
Keren Maor-Landaw1, Fiorella Prada2, Stefano Goffredo2, Zvy Dubinsky1 and Oren Levy1
1
The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel.
Marine Science Group, Department of Biological, Geological and Environmental Sciences, Alma Mater
Studiorum–University of Bologna, Bologna, Italy.
2
Rapid increase in atmospheric CO 2 concentration is causing global warming and ocean
acidification threatening scleractinian corals survival due to their adaptation to a narrow range of
temperatures and pH conditions. Recent researches indicate the semi-enclosed Mediterranean
Sea as particularly sensitive and vulnerable to increasing atmospheric CO 2 due to its
oceanographic characteristics. Here we studied acidification effects during summer and winter
time looking at the Mediterranean scleractinian coral Balanophyllia europaea that was
transplanted along a natural pH gradient off the Island of Panarea (southern Italy). We also
tested the physiological performance in a closed aquaria system with controlled pH and
temperature conditions. Coral mortality was studied in the field experiment, using a series of
photographs taken throughout the year along the pH gradient ranging from 8.1 to 7.4. The
results showed enhanced mortality linked to the decreasing pH only during the summer season.
The B. europaea polyps that were subjected to a long-term experiment under controlled
conditions: constant pH of 7.8 and moderate increasing temperature of 1°C/three weeks, from
17°C to 29°C showed a decrease in photosynthetic efficiency (Fv/Fm). While under lower
temperatures <20°C no decrease was observed in Fv/Fm values. These results imply on a
synergistic effect between pH and temperature: under high temperatures B. europaea polyps are
more sensitive to low pH, showing lower photosynthetic efficiency and finally death. These
experiments are part of a broader project called coral warm aimed at generating projections of
temperate and subtropical coral survival under sub-lethal temperature increase and ocean
acidification. We compared our results with the tropical Red Sea Stylophora pistillata using
physiological and genomic tools.
RECOGNIZING SEICHE AND TSUNAMI IN LAKE SEDIMENTS
Shmuel Marco1, Ian G Alsop2, Oded Katz3 and Yehoshua Dray4
1
Department of Geophysical, Atmospheric, and Planetary Sciences, Tel Aviv University [email protected]
Department of Geology and Petroleum Geology, School of Geosciences, University of Aberdeen, UK
[email protected]
3
Geological Survey of Israel, Jerusalem [email protected]
4
Restoration of Ancient Technology, Binyamina [email protected]
2
Our study aims to identify evidence for tsunami and seiche in sediments of ancient lakes. The
first case study is the lacustrine 70-15-ka Lisan Formation outcropping around the Dead Sea,
which contains superb examples of slump folds formed in water depths of <100 m. New
structural field data from individual horizons demonstrate that several of these gravity-driven
slumps are coaxially refolded and reworked by folds and thrusts verging both back up and then
down the palaeoslope. The uppermost folds are often truncated. A progressive increase in
reworking and shearing is developed up through the folded sediment, culminating in an upwardfinning breccia layer that is capped by a thin, typically graded horizon of undeformed fine-grained
clasts. We interpret this sequence as a seiche-related deformation. Based on the similarity of the
structures in the Lisan Formation and on additional supporting observations we examine a second
case in artificial lake deposits on the Eastern Mediterranean shore. We interpret zigzag-shaped
sand injections as evidence for a tsunami, possibly associated with the earthquake of 25
November 1759. If correct, this interpretation supports the hypothesis that onshore Dead Sea
Fault earthquakes can trigger tsunamis in the Mediterranean
THE ORIGIN OF BIODIVERSITY IN THE DEEP MEDITERRANEAN BASIN
Orit Nir, Max Rubin and Danny Tchernov
University of Haifa, The Leon H.Charney School of Marine Sciences, department of Marine Biology
[email protected], [email protected], [email protected]
Global climatic changes of glacial and inter glacial periods had a dramatic effect on the
Mediterranean oceanographic conditions, forcing extinctions, low endemism and discrete
evolution in the basin. The desiccation of the Mediterranean Sea in the late Miocene (the
Messinian event 5.96-5.3 MY) followed by numerous anoxic events that created sapropel
deposits, markedly influenced the deep Mediterranean basin biodiversity. The anoxic events
effected the deeper areas of the basin (>300 m), causing repeated and similar disturbances and
extinctions. Following the sapropel formation events, organisms from the Atlantic Ocean entered
and recolonized the Mediterranean basin. We hypothesize that organisms originating from deep
ventilated environments will show grate similarity to their Atlantic relatives or/and will have a
large range of bathymetric distribution due to the repeated recolonization events. Organisms
tolerant to low oxygen concentrations, such as fauna found in the vicinity of methane seeps, have
the capacity to survive the disturbances and continue to evolve in the separated basin. Hence this
fauna will be highly different from their relatives in the World Oceans and most likely endemic.
During the expedition of the E/V Nautilus in the East Mediterranean basin (2010, 2011), we
identified the most abundant deep benthic species. Our findings, (also supported by an extensive
literature survey) support the latter hypothesis. In methane seeps related fauna, various
molecular markers of most organisms varied (>92%) from their World Ocean relatives, as
opposed to molecular markers from ventilated environment organisms that were highly similar
(95%-100%). Moreover, most benthic organisms considered previously in the literature as
endemic to the deep Mediterranean basin were recently described in the Atlantic Ocean.
‫מה קרה לשלל הדיג בכנרת בשנת ‪ ?2112‬פתרון התעלומה באופן לא צפוי‬
‫‪1‬‬
‫איל אופיר‪ 1,2‬וגדעון גל‬
‫‪ 1‬חקר ימים ואגמים‪ ,‬המעבדה לחקר הכנרת ‪[email protected], [email protected]‬‬
‫‪ 4‬אוניברסיטת חיפה‪ ,‬בית הספר למדעי הים‪ ,‬החוג לציוויליזציות ימיות‬
‫המערכת האקולוגית בכנרת נתונה לשינוים רבים במהלך העשרים השנים האחרונות ברמות‬
‫הטרופיות השונות‪ .‬גם הדיג בכנרת מתאפיין‪ ,‬בשנים האחרונות‪ ,‬בחוסר יציבות קיצוני ובהפחתה‬
‫משמעותית של כמות השלל בעיקר של המינים בעלי הערך המסחרי הגבוה ביותר‪ ,‬כגון אמנון‬
‫הגליל‪ ,‬הכסיף‪ ,‬והבורי‪ ,‬עד כדי אפשרות היעלמותם מסל הדיג בכנרת‪ .‬על פי נתוני אגף הדיג חלה‬
‫ירידה בשלל הדיג הכולל מ‪ 410, -‬טון בשנת ‪ 1,,2‬לכמות של ‪ 221‬טון בשנת ‪ .4117‬בשנת ‪4112‬‬
‫הגיע שלל אמנון הגליל‪ ,‬הדג בעל הערך המסחרי הגבוה ביותר‪ ,‬ל‪ 2-‬טון בלבד‪ ,‬ירידה של ‪ ,2%‬ב‪-‬‬
‫‪ 11‬שנים וב‪ ,1%-‬ביחס לשלל שנרשם רק ב‪( 4112-‬נתוני אגף הדיג‪ ,‬ועדת אכלוס כנרת ‪.)4.7.411,‬‬
‫הדיג משפיע לא רק על הכנסות הדייגים‪ ,‬אלא גם על יציבות המערכת האקולוגית בכנרת‪ ,‬ממנה‬
‫הוא ניזון‪ ,‬ולכן קיים צורך בהבנת הגורמים המשפיעים על כמות הדגה באגם‪ .‬על מנת לבחון את‬
‫הסיבות האפשריות לנפילת שלל הדיג בכנרת בשנת ‪ ,4112‬השתמשנו בסדרה של מודלים מסוג‬
‫‪ .(Ecopath and Ecosim) EwE‬בבסיסה‪ ,‬תוכנת ‪ EwE‬יוצרת מודל מאזני של מערכת אקולוגית‬
‫מורכבת‪ ,‬בעיקר על בסיס קשרי המזון של כלל הרכיבים במערכת כולל גם מרכיבים כגון לחץ דייג‬
‫וטריפה ע"י עופות‪ .‬לאחר שנוצר המאזן והתוכנה בדקה כי אכן המערכת מאוזנת והקשרים בין‬
‫הפרטים הם הגיוניים‪ ,‬ניתן לבחון תוצרי בסיס של המערכת כמו‪ :‬רמות טרופיות‪ ,‬צריכה‪ ,‬קשרי מזון‪,‬‬
‫זרימת האנרגיה ועוד‪ .‬על בסיס מודל זה ניתן ליצור שינויים במערכת ולבחון את השפעתם על‬
‫המערכת האקולוגית בכלל‪ ,‬ואוכלוסיות הדגים‪ ,‬בפרט‪ ,‬לאורך זמן‪ .‬כמו כן‪ ,‬ניתן לבחון תרחישי‬
‫ניהול שונים ומורכבים לאורך זמן‪.‬‬
‫על מנת לבחון את מגוון הגורמים שיכלו להשפיע על שלל‬
‫אמנוני הגליל בשנת ‪ ,4112‬השתמשנו ביכולת הסימולציה של המודל‪ .‬שיטת הבדיקה כללה שינוי‬
‫ברכיבים המשפיעים על אוכלוסיית אמנוני הגליל בשנים שקדמו לירידה המשמעותית בשלל‬
‫(‪ .)4112‬למשל הפסקת הדיג בשנה שלפני‪ ,‬צמצום הטריפה ע"י קורמורנים ועוד‪ .‬כל זאת מתוך‬
‫הבנה כי הסיבות לשינוי בשלל נעוצות בשנים שקדמו לכך‪ .‬אולם הסתבר שהסיבה לשינוי נעוץ‬
‫בתהליך בלתי צפוי‪.‬‬
THE COEXISTENCE OF MOTIONS OF DIFFERENT SCALES IN OCEANS AND
OTHER NATURAL WATER BASINS PRESENTS A CHALLENGE FOR THEIR
DYNAMIC MODELING
Brenda Quinn
Tel-Aviv University [email protected]
The usual approach for water waves on a current, exploits the disparity of scales to separate
equations describing the propagation of fast/short surface waves in the slowly varying
environment and equations for slow/long currents, formulated mathematically as an asymptotic
procedure. In the leading order it allows one to tackle separately two motions of a qualitatively
different nature. To describe wave propagation over large distances, the corresponding wave
evolution equations are further simplified by phase averaging yielding an evolution equation for
the wave action which depends only on slow space and time variables. The commonly used
wave action equation is however, restricted to slowly varying bottom depths and vertically
averaged ambient currents. On the other hand, ocean circulation models take into account the
vertical variability of the flows. When both types of models are coupled together, the physics
modeled by the wave action equation are inferior to those of the ocean circulation models since
water waves almost always propagate on a current with a pronounced vertical curvature. I will
present the derivation and examination of an improved wave action equation, typical of that used
in wave forecasting models, which takes into account the vertical structure of the large scale
current. The developed wave action formulation greatly improves the representation of linear
wave-current interaction in the case of tidal inlets, wind-induced currents, storm surges and
undertow currents. The structure of the oscillatory flow under the wave depends on vertical
structure of the current, so various velocity profiles will be examined numerically, since for an
arbitrary current profile, the Rayleigh equation boundary value problem, which describes the
wave profile and speed, does not have an exact analytical solution. An asymptotic solution is
used, assuming a small curvature, small slope and a small velocity of the current profile.
‫הקמת המרכז לתיוג ימי של מגוון יצורי ים תיכון לאורך חופי ישראל‬
‫גיא פז‪ ,‬לי שיש‪ ,‬יעקב דואק‪ ,‬הדס לובינבסקי ובוקי רינקביץ'‬
‫המכון הלאומי לאוקיאנוגרפיה‪ ,‬חקר ימים ואגמים‪ ,‬חיפה‬
‫בתחילת שנת ‪ 4111‬נאמד המגוון הביולוגי באוקיינוסים בכ‪ ,,,,111 -‬מינים‪ ,‬הנמנים על ‪ ,1‬קבוצות‬
‫של אורגניזמים רב‪-‬תאיים‪ ,‬מהם הוגדרו עד כה כמחציתם‪ .‬יחד עם זאת‪ ,‬נראה שמספר וזהות כלל‬
‫המינים הימיים לא ייוודעו לעולם בשל שיעור הכחדה גבוה וקשיי נגישות לחלקים נרחבים של‬
‫האוקיינוסים בשל עומקם‪ .‬השינויים בסביבה הימית כתוצאה מהשפעת האדם‪ ,‬הניכרים בעיקר‬
‫במדף היבשת‪ ,‬מחזקים את הצורך בתיעוד מדויק‪ ,‬מהיר ויעיל של המגוון הביולוגי‪ .‬במקביל‪ ,‬הדעיכה‬
‫במספר הטקסונומים המורפולוגיים מגבילה את האפשרות לעמוד בקצב זיהוי הפרטים‪ ,‬תאור מינים‬
‫חדשים למ דע ובחינתם לצורך לימוד קשריהם האבולוציוניים והביוגיאוגרפיים‪ .‬לתיעוד הכחדת מינים‬
‫מחד‪ ,‬ופלישת מינים לבתי גידול חדשים מאידך‪ ,‬המתרחשים בקצב מהיר‪ ,‬נדרשים כלים מהירים‬
‫וזמינים המסוגלים לסייע בניטור מערכות אקולוגיות‪ .‬בים התיכון כדוגמה‪ ,‬זוהו כבר למעלה מ‪411 -‬‬
‫מינים זרים של דגים‪ ,‬חסרי חוליות ואצות‪ .‬בחוף הים תיכוני של ישראל לבדו דווחו למעלה מ ‪,,4‬‬
‫מינים זרים – אשר מרביתם הגיעו מים סוף דרך תעלת סואץ‪ .‬למרות שאין ספק שמספרם של‬
‫המינים זרים גדול אף יותר אין בידנו כלים יעילים לעקב אחר תופעה זו‪.‬‬
‫לצורך לימוד המגוון הביולוגי הימי‪ ,‬החלנו לפני כשנתיים בבניה והקמה של מאגר נתונים של‬
‫האורגניזמים הימיים המצויים לאורך חופי ישראל (המרכז לתיוג ימי של מגוון יצורי ים תיכון לאורך‬
‫חופי ישראל) המסתמך על הידע והמיומנות של טקסונומים זמינים‪ ,‬שיטות מולקולריות חדישות‬
‫המשתמשות ברצפי ‪ DNA‬וקישוריות עם מאגר‬
‫‪ BOLD‬העולמי‪ .‬עד כה זוהו והועלו למאגר מאגר‬
‫המידע האינטרנטי הבינלאומי דפי המידע על ‪ ,22‬מינים ימיים‪ ,‬מהם ‪ ,,0‬דגים‪ 4, ,‬סרטנים‪41 ,‬‬
‫רכיכות (יצורי ה‪ VOUCHER-‬מתויגים במוזאונים הלאומיים) ובקרוב יועלו לאתר דפי המידע של מיני‬
‫אצות וחסרי חוליות נוספים‪ ,‬הן מאזור הליטורל‪ ,‬מאזור מדף היבשת‪ ,‬ועד לאזורי ים עמוק‪ .‬היצורים‬
‫השונים נדגמו הן מאזור המים הפתוחים והן מאזורי השונית הסלע‪ ,‬והחול‪ .‬המאגר יהיה פתוח בפני‬
‫ציבור המדענים‪ ,‬הסטודנטים וכן לציבור הרחב‪ .‬בנוסף‪ ,‬למאגר הבינלאומי בימים אלה הולך ומושלם‬
‫מיזם של מרכז תיוג ימי ישראלי במכון לחקר ימים ואגמים‪ ,‬שיאפשר גישה לכלל המידע הכולל‬
‫תמונות‪ ,‬רצפי ‪ ,DNA‬מקומות איסוף ונתוני מורפולוגיה שונים‪ .‬אנו קוראים בזאת לשיתוף פעולה בין‬
‫כל המדענים הישראלים בהקמת המרכז לתיוג ימי ובתיוג מינים ימיים נוספים‪.‬‬
GRAVITY WAVES ON A ROTATING AQUA-PLANET: THE EVASIVE KELVIN WAVE
Nathan Paldor
Fredy and Nadine Herrmann Institute of Earth Sciences, The Hebrew University of Jerusalem, Edmond J.
Safra Campus, Givat ram, Jerusalem, 91004. [email protected]
Gravity waves are probably the most common type of linear waves in fluid mechanics and their
importance is related to the fact that their phase speed is also the slope of the characteristics of
the associated non-linear dynamics. In non-rotating, Shallow Water, fluid flows gravity waves can
be easily derived in an invariant, i.e. coordinate free, form by, say, eliminating the velocity and
deriving a wave equation for the height in which the constant coefficient of the spatial second
order derivative is identified as the phase speed. However, in a rotating fluid where Coriolis
acceleration is added to the momentum equations this straightforward derivation is no longer
possible and a more elaborate derivation has to be employed. Such derivations exist in Cartesian
coordinates in a channel (both the mid-latitudes f/-planes and on the equatorial -plane) and on
the unbounded equatorial -plane. On the other hand, in spherical coordinates the derivation of
gravity waves in rotating fluids is very complex and no systematic derivation of these waves can
be formulated. In my talk I will highlight the relationship between Gravity Waves in non-rotating
fluids and Kelvin Waves in a rotating fluid and how this association between the two wave types
can be used to derive a theory for Kelvin waves on a rotating sphere such as an aqua-earth. As
the work is still in progress only initial thoughts will be presented along with initial numerical
calculations that provide an important predecessor for the analytical derivation.
"KEEP ON ROCKING"- UNIQUE OSCILLATORY BEHAVIOR OF COLD SEEP
SPIONIDS
Yotam Popovich*1, Maxim Rubin-Blum*1, Eli Shemesh1, Beverly Goodman-Tchernov1, James A
Austin, Jr2, Dwight F Coleman3, David F Gruber4, Uri Shavit5 and Dan Tchernov1
1
The Leon H. Charney School of Marine Sciences, University of Haifa, Israel [email protected]
Institute for Geophysics, The University of Texas in Austin, TX, USA
3
Graduate School of Oceanography, The University of Rhode Island, RI, USA
4
Department of Natural Sciences, City University of New York, Baruch College, NY, USA
5
Civil and Environmental Engineering, Technion, Haifa , Israel
*
equally contributed
2
During the 2011 E/V Nautilus expedition of the Levantine basin's cold hydrocarbon seeps, we
observed vast densities of Spionidae (Prionospio sp.), a family within the Polychaeta that are
common dominant members of soft-sediment communities, inhabiting hydrocarbon enriched
euxinic sediment, at 1000 m depth. As they reside near the sediment interface, Spionids are an
important food source for many benthic feeders and therefore are likely to affect the structure of
many other benthic communities. Gas bubbling within the populated patch triggered the spionids
to move their upper body part and palps in an oscillatory “rocking” manner. This motion falls
within an understudied range of flow parameters. This research aims to quantify the oscillatory
motion contribution to the spionids populating anunexplored harsh niche, characterized by slow
water flow, scarce nutrition and periodic bursts of food supply. The oscillatory motion caused
large changes in the characteristics of spionids’ immediate environment. Typical physical
parameters describing it show high mixing rate, dominant advection and a relatively high
Reynolds Number associated with the spionid length scale, causing the formation of asymmetrical
vortices attached downstream to the spionid. The water volume effective for particle sampling by
the spionid is 15 times bigger due to the oscillation, enhancing particle capture success. Given a
unidirectional flow for reference, unwanted particles may stay trapped within the attached
vortices. The oscillatory motion creates strong lateral component that carry away these waste
particles otherwise trapped. The removal of the waste particles can be beneficial not only to a
spionid, but also to spionid associated bacteria by accelerating mass transfer mechanisms.
Utilizing molecular tools, we show the potential for involvement of sulfide-metabolizing bacteria
as participants in the detoxification of sulfide originating from the gas seepage, strengthening the
studied link between spiniods' oscillating behavior and deep eastern Mediterranean euxinic seeps.
INTER-ANNUAL VARIABILITY OF COASTAL PHYTOPLANKTON AND BACTERIA
OFF HAIFA COAST, EASTERN MEDITERRANEAN SEA
Eyal Rahav
Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
[email protected]
The seasonal succession of phytoplankton and bacteria were investigated on a weekly basis from
April 2013 to March 2014 at a station off Haifa coast, Eastern Mediterranean Sea. Heterotrophic
bacteria were abundant throughout the entire year (4×10 5 to 1×106 cells ml-1) peaking in
midsummer when nutrients were scarcest. Bacterial productivity (BP) ranged from 0.5 to 1.3 µg C
L-1 h-1 correlating positively with bacterial abundance (BA) and temperature. Seasonal succession
in the phytoplankton community was evident in the abundance of picophytoplankton during
summer (~2.5×104 cells ml-1), followed by microphytoplankton in winter/early spring (> 70 % of
total chlorophyll a). These community shifts were also evident in the primary productivity rates
(PP); while during summer most of the PP was mediated by picophytoplankton (0.3- 1.8 µg C L-1
h-1, ~75 % of total PP), microphytoplankton PP were more significant during spring (0.6- 7.9 µg
C L-1 h-1, > 50 % of total PP). This study is the first attempt to routinely follow phytoplankton and
bacteria dynamics off the Israeli coast and can be used as baseline for further research.
NERVOUS NECROSIS VIRUS (NNV): CHARACTERIZATION OF THE IMMUNE
RESPONSE TO VACCINATION IN WHITE GROUPER EPINEPHELUS AENEUS
Shay Ravid- Peretz1,2, Koby Tarrab1,2, Angelo Colorni1, Michal Ucko1 and Moshe Kotler3
1
Israel Oceanographic and Limnological Research, National Center for Mariculture, P.O. Box 1212, Eilat
88112, Israel
2
Department of Life Sciences, Ben Gurion University, Eilat Campus, Israel
3
Department of Immunology and Pathology, Hebrew University of Jerusalem, Hadassah Medical School,
Jerusalem, Israel
[email protected], [email protected], [email protected], [email protected],
[email protected]
Viral Nervous Necrosis (VNN) is a fish disease that has spread worldwide in aquaculture over the
last two decades. More than 30 species of marine fish are known to be susceptible to its
etiological agent – Nervous Necrosis Virus (NNV). The disease causes severe mortalities,
particularly during larval and grow-out stages, inflicting tremendous economical losses in Israeli
mariculture and threatening the domestication of the white grouper ( Epinephelus aeneus) and
other commercially important species. VNN produces necrosis and vacuolization of nervous
tissues. Clinical signs include reduced coordination, loss of balance, erratic swimming, and
blindness. Infection is normally horizontal (i.e., fish to fish), but vertical transmission (i.e., parents
to progeny) has been reported as well. A vaccine capable of inducing protective immunity in fish
could lead to the effective control of the disease and significantly reduce economic losses in the
fish industry in Israel and worldwide. An immune response to the inactivated NNV virion and to a
recombinant coat protein has been obtained in several farmed fish species. However, none of
NNV experimental vaccines developed to date is commercially available. Aiming to the
development of an antiviral vaccine, we have characterized the white grouper (E. aeneus) short
and long terms immune response to NNV infection. The fish were vaccinated by intramuscular
injection (IM) using NNV vaccine. Thirty-two days post-vaccination, the fish were challenged
using NNV propagated in cell culture, while control group was injected with Leibovitz's
L-15
medium. Post-challenge mortality rates and abnormal behavior of the injected fish were
monitored and recorded. Sixty days post-vaccination, the survived fish were challenged again IM
in order to evaluate the immunization memory. Samples of spleen, kidney, and brain tissue were
collected for histopathological and molecular analyses 14 and 32 days post-vaccination. Blood
was drawn from the caudal vein weekly and the serum analyzed by RT-qPCR and ELISA in order
to evaluate antibody kinetics and acquired immunity. Preliminary results show a significant
increase in specific anti-NNV antibodies activity and higher expression levels of interferon (MX)
starting 15 days post-infection in the fish sera.
THE VALUE OF LONG-TERM, SYSTEMATIC, ECOLOGICAL MONITORING –
TRENDS AND LESSONS FROM THE ISRAELI MEDITERRANEAN VERMETID
REEFS
Gil Rilov, Ohad Peleg, Ofrat Rave and Niv David
National Institute of Oceanography, Israel Oceanographic and Limnological Research (IOLR), Haifa, Israel
[email protected]
The Israeli Mediterranean shore is perhaps one of the most changing coastal systems of the
world. It also hosts one of the most unique intertidal ecosystems worldwide – the biogenic
formations known as “abrasion platforms” or “vermetid reefs”. Unfortunately, apart from old,
mostly descriptive, investigations of the communities of this ecosystem, or short-term studies
focused on single species, there has not been a systematic study of the community structure and
dynamics of vermetid reefs, let alone the ecological processes on them. In 2009, IOLR has
initiated a pilot monitoring program that turned in 2013 into a national monitoring program on
the ecological communities of vermetid reefs and their biogeochemical and physical environment.
The program includes (1) annual ecological sampling of 11 sites from north to south, (2) seasonal
ecological sampling of four core sites, (3) monthly sampling of biogeochemical and physical
seawater properties at the core sites, and (4) hourly temperature logging. Results so far indicate
high spatial variability in community structure on a coastal scale, distinct zoning on a local scale,
and a strong seasonal signal of community structure and diversity. Communities differ between
the northern and the central and southern parts of the coast. Diversity is highest in winter/spring
and lowest in autumn/summer, probably because of desiccation events that cause extensive
bleaching during late spring and autumn. Interestingly, some species show a different degree of
seasonality depending on their location along the coast. There are also large seasonal and interannual fluctuations in sediment cover on the rocks, in chlorophyll levels, and of course in
temperature, salinity and nutrients. Remarkably, the extreme warm and dry winter of 2014 left its
detrimental marks also on the intertidal community. This evidence for a dynamic system
demonstrates the value of ecological monitoring in this era of change and growing environmental
awareness.
REGIONAL NEAR-EXTINCTIONS AND INVADERS’ DOMINATION: AN
ECOSYSTEM PHASE-SHIFT OF LEVANT REEFS
Gil Rilov
National Institute of Oceanography, Israel Oceanographic and Limnological Research (IOLR), Haifa, Israel
[email protected]
Using past sporadic data and data from current (2009-2013) extensive surveys and a monitoring
program along the entire Israeli coast I show that the previously Atlanto-Mediterranean
dominated biota of the Levant rocky reefs (intertidal and subtidal) on the Israeli shore is going
through recent major shifts in its biodiversity. Several ecologically important species (a reefbuilding vermetid gastropod, sea urchins and a large predatory snail) exhibited major population
collapses while several key taxonomic groups (gastropods and bivalves and to some extent fish)
are completely dominated by IndoPacific invaders. I suggest that this biogeographic shift may be
partly driven by global climate change. The southeastern coastal waters of the Mediterranean
have warmed by 2-3 °C in the past two decades and may have become too hot for some
indigenous species and more hospitable to tropical ones. This means that the climatic envelope of
the native species may have shrunk or shifted. Recent lab and field experiments indicate that the
abundant sea urchin, Paracentrotus lividus, is indeed dying during peak summer SST on the
Israeli coast, and its feeding and reproductive potential are reduced by invasive herbivorous fish.
Performance curves (e.g., photosynthesis) of several still-abundant (mainly during colder months)
native species show that their physiological activity is greatly reduced when exposed to peak and
future summer temperatures. Clearly, the ecological implications of these species collapses and
invasions, including their effects on ecosystem functions, must be profound and are currently
studied.
AN ANOMALY WITHIN ca. 300 m DOR DISTURBANCE IRON ENRICHED
SEDIMENTS: MARINE GEOCHEMISTRY, TSUNAMIS AND PROBIOTICS
Maxim Rubin-Blum, Eli Shemesh, Beverly N. Goodman-Tchernov, Dan Tchernov
The Leon H. Charney School of Marine Sciences, University of Haifa
[email protected]; [email protected]; [email protected];
[email protected]
During the 2010-2011 E/V Nautilus exploration of the Levantine basin’s benthos, we studied
patchy mats formed by iron oxidizing zetaproteobacteria, that may influence marine geochemical
cycles1. In order to better understand mechanisms forming the mats, we have sampled surface
sediments at a depth of ca. 300 m offshore Dor and employed a wide range of geochemical,
micropaleontological and microbiological investigative techniques. Short cores, about 15 cm deep,
were collected and subsampled at 1 cm resolution. The analysis of each layer included grain size
analysis, elemental analysis by X-ray fluorescence, detailed study of foraminifera assemblages
and tag-encoded FLX amplicon pyrosequencing of bacterial populations. We were surprised to
discover an anomaly, characterized by significant fluctuations in nearly all parameters. The
foraminifer assemblage within the anomalous layer resembled shallow water, estuarine
assemblages rather than the typical 300 m assemblage. Moreover, we have found that 5 -7 cm
sections are populated by a unique bacteria consortium, enriched with fermenters highly
resembling bee gut microbiota. Such consortium can be involved in digestion of buried refractory
organic matter, providing metabolites to other life forms. We suggest that a mass transport event
of a large magnitude such as tsunami has formed the anomalous layer, creating a hidden organic
enrichment that potentially fuels the productivity in the upper sediment layers.
1
Rubin-Blum M et al. (2014) First evidence for the presence of iron oxidizing zetaproteobacteria
at the Levantine continental margins. PLoS One 9(3): e91456
‫דג ישן – טפיל חדש‪ :‬יש מאין?‬
‫שבי רוטמן‪ ,1‬מנחם גורן‪ 1‬ואריק דיאמנט‬
‫‪2‬‬
‫‪1‬המחלקה לזואולוגיה‪ ,‬מוזיאון הטבע הלאומי ומרכז המחקר ע"ש שטיינהרדט‪ ,‬אוניברסיטת תל‪-‬אביב‪.‬‬
‫‪[email protected] [email protected],‬‬
‫‪4‬חקר ימים ואגמים לישראל‪ ,‬המרכז הלאומי לחקלאות ימית‪ ,‬אילת‪[email protected] .‬‬
‫הגירת אורגניזמים מים סוף לים התיכון דרך תעלת סואץ נחשבת להגירה הביולוגית הימית‬
‫המרשימה ביותר בימינו‪ .‬בעשור האחרון החל מאמץ המחקר המתמקד בתופעה זו לעלות‪ ,‬ובמקביל‬
‫עלה קצב הדיווח על הגעת מינים מהגרים חדשים למזרח הים התיכון‪ .‬בעוד התיעוד של מינים‬
‫חופשיים שהיגרו מים סוף לחופי הים התיכון זוכה להתייחסות רבה‪ ,‬ההגירה של מינים טפיליים על‬
‫גבי מאכסנים שהיגרו זוכה להתייחסות מועטה‪ .‬הדג המהגר שפריר החוט ‪Callionymus filamentosus‬‬
‫תועד לראשונה לפני כ‪ 01 -‬שנה מחופי תל‪-‬אביב‪ .‬היום נחשב שפריר החוט לאחד ממיני הדגים‬
‫הנפוצים בחופינו באזורים חוליים רדודים‪ .‬במסגרת מחקר שבחן את הרכב אוכלוסיית הדגים לחופי‬
‫הים התיכון הישראלי ובחופי טורקיה נבדקה נוכחות טפילים על גבי דגים ילידים ודגים זרים במטרה‬
‫לבחון את מעורבות הטפילים בתופעת ההגירה‪ .‬במהלך המחקר התגלו שני מיני טפילים על גבי‬
‫שפריר החוט; (‪ )1‬נקבות שפריר החוט היו נגועות באופן חריג בשחלות על ידי טפיל פנימי מקבוצת‬
‫המיקרוספורידיה‪ ,‬בעוד זכרים לא הציגו סימני נגיעות כלל (‪ )4‬זכרים ונקבות השפריר היו נגועים‬
‫בטפיל חיצוני‪ ,‬סרטן שטרגל‪ ,‬המצוי על גבי הזימים‪ .‬שני מיני הטפילים לא היו ידועים למדע ותוארו‬
‫כמינים חדשים בעקבות ממצאי המחקר‪ .‬בבדיקת שכיחות הנגיעות בטפיל המיקרוספורידיה התגלה‬
‫כי ברב עונות השנה‪ ,‬ביותר מ ‪ 21%-‬מהנקבות נמצאו שחלות נגועות‪ .‬בנוסף נמצא כי עוצמת‬
‫הנגיעות במיקרוספוריד היתה גבוהה ובכ‪ 21% -‬מהנקבות תפס הטפיל את רב נפח השחלות‪ .‬על‬
‫מנת לעקוב אחר הכרונולוגיה של הופעת שני מיני הטפילים נבדקו פרטים של שפריר החוט באוספי‬
‫הטבע באוניברסיטת תל אביב ובאוניברסיטה העברית ונמצא כי טפיל השטרגל הופיע לראשונה על‬
‫גבי דגים שנאספו בשנת ‪ ,1,,7‬ואילו טפיל המיקרוספורידיה הופיע לראשונה מספר שנים לאחר‬
‫מכן‪ ,‬בדגים שנאספו בשנת ‪ .4112‬בבדיקות מולקולריות נמצא דנ"א של המיקרוספוריד בשטרגל וכן‬
‫באיברים פנימיים שונים של דגים זכרים‪ .‬ממצאים אלו מצביעים על באפשרות הדבקה וקטורית‬
‫באמצעות טפיל השטרגל אולם לא ניתן לקבוע זאת באופן וודאי‪ .‬למרות ששני מיני הטפילים אינם‬
‫ידועים מאזור תפוצתו המקורית של שפריר החוט‪ ,‬ההנחה היא כי שניהם היגרו מים סוף לים התיכון‪.‬‬
3D NAVIGATION IN CUTTLEFISH: PREFERENCE OF VERTICAL OVER
HORIZONTAL INFORMATION
Gabriella Scatà1, Christelle Jozet-Alves2 and Nadav Shashar1
1
Department of Life Sciences, Ben Gurion University of the Negev, Eilat Campus, Beer-Sheva, Israel
[email protected]
2
Groupe Mémoire et Plasticité comportementale, Université de Caen Basse-Normandie, Caen, France
Although the world is three-dimensional, spatial cognition has been extensively studied mostly in
two-dimensional environments. Several studies showed a difference in the way freely moving
species learn spatial information in the two dimensions and integrate it into an internal
representation of space as compared to surface-bound species, which prioritize the horizontal
dimension and encode it with higher resolution. Cephalopods have remarkable spatial abilities
and can move freely in a volume, yet some species, such as cuttlefish, are bottom-dwelling
animals, making them an interesting model for the study of three dimensional navigation. We
tested the relative preference of vertical vs. horizontal information in trained Sepia officinalis
cuttlefish. Animals were trained to approach one of two visual cues arranged in a 45°
configuration, either up and right or down and left. After reaching the learning criterion, the
animals were sequentially presented 3 different test configurations of the two visual cues, with
training trials in between. In the first two tests the animal was presented either with a horizontal
or a vertical configuration of the two visual cues. These tests assessed whether the animal could
extract the vertical or the horizontal coordinate from the previously learned three-dimensional
spatial location of the rewarded visual cue. Most animals made a correct choice in both tests. The
last test presented a conflict situation, in which the two visual cues were arranged in a 45°
configuration opposite to the training one. Animals significantly chose the visual cue which was
consistent with the previously learned vertical information. Hence, cuttlefish can separately learn
and extract the vertical and horizontal coordinates of a three-dimensional location, and the
vertical component of space seems to have a greater importance than the horizontal component.
SEAWATER CHEMISTRY EFFECT ON ECOSYSTEM CORAL REEF CALCIFICATION
Kenneth Schneider1,2, Ben Kravitz3, Jacob Silverman4, Kathrine Ricke 1, Julia Pongratz1,5 and
Ken Caldeira1
1
Carnegie institution for Science, Stanford, CA, USA
The Bar Ilan University, Ramat Gan, Israel
3
Pacific Northwest National Laboratory, Richland, WA, USA
4
Israeli National Institute of Oceanographic and Limnological Research, Haifa, Israel
5
Max Planck Institute for Meteorology, Hamburg, Germany
2
Coral Reefs are among the most biodiverse ecosystem in the earth and in recent decades
experimental and observational studies have shown that ocean acidification may threaten the
well being of coral reefs by reducing their CaCO 3 accretion rate lower than their erosion rate. In
this report we present findings of an in-situ novel experimental study that demonstrates for the
first time the community calcification response of a coral reef flat in One Tree Reef, Great Barrier
Reef, Australia, to alkalinity enrichment. During these experiments water flowing onto the reef
was enriched by 155±20 μmole/kg with NaOH during low tide periods when the flow of water
across the reef flat is unidirectional. The alkalinity enriched plume was followed by adding to it
Rhodamine WT dye. Water was sampled before and during the enrichments across the reef flat in
the direction of the flow. Total alkalinity gradients were used to calculate rates of net ecosystem
calcification (NEC) before and after the enrichment. The NEC values for both natural and enriched
conditions were positively correlated with aragonite saturation (arag). Although alkalinity
enrichment does not exactly mimic the effects of increasing atmospheric CO2 and ocean
acidification, it is clear that the calcification response of a natural coral reef to changes in arag is
instantaneous and positively correlated.
THE TIDAL RHYTHMICITY AND ENTRAINMENT OF THE RED-SEA LIMPET
CELLANA ROTA
Yisrael Schnytzer1, Noa Simon-Blecher2, Yair Achituv3 and Oren Levy4
The Mina and Everard Goodman Faculty of Life Sciences, Bar- Ilan University, Gamat-Gan, Israel
1
[email protected], [email protected], [email protected] , [email protected]
Cellana rota is the most common limpet species, and perhaps one of the most abundant intertidal
animals, occurring on the shores of the Red-Sea. Despite this, little is known about its behaviour,
particularly with regard to rhythmicity and what cues govern its activity. Using time-lapse
photography, we are currently monitoring a natural population of C. rota in the Gulf of Eilat. Data
collected thus far, over the course of a year, indicate that the limpets are active in synchrony with
the tides, irrespective of the day-night cycle. They are active with the rising and ebbing of the
tide, but not around the high and low tides. During low tide, most of the limpets stay in the
shaded low part of the boulder, moving upward with the first splashes of the incoming tide.
Whilst active, the limpets forage on the upper side of the boulder, ceasing movement once fully
immersed. The limpets show anticipatory behaviour, returning to their "home" well before the
boulder is submerged, suggesting the presence of an endogenous clock. In the laboratory, in the
absence of tidal cues, under constant light conditions (LL, DD and LD), C. rota maintains a tidal
rhythmicity for at least several days before its fading off. The light/dark cycle appears to have no
entraining effect on their behaviour. Limpets kept for longer periods of time, under LD and DD
conditions without tidal cues, can be entrained to periods of simulated “sea spray”, regaining
their tidal rhythmicity. We have identified homologs of six core circadian clock genes in C. rota.
Partial sequences of cry1, cry2, cry-dash, bmal1/cycle, timeless1 and a gene similar to period
have been identified. In addition, a partial sequence of Hif1a, a hypoxia regulatory gene has been
identified. Using several approaches, we are currently assessing the role of these genes in the
circadian and circatidal clock machinery.
APLYING PRINCIPLES OF RECONCILIATION ECOLOGY IN
ENVIRONMENTALLY SENSITIVE DESIGNS OF COASTAL DEFENSE
STRUCTURES: THE POLINOM CASE STUDY
Ido Sella1,2 and Shimrit Perkol-Finkel1,2
1
SeArc - Ecological Marine Consulting LTD, Namirover 13 Tel Aviv 69713 [email protected]
ECOncrete Tech LTD, Namirover 13 Tel Aviv 69713 [email protected]
2
With the proliferation of human population along coastlines, alongside with growing threats from
sea level rise and increased storminess, costal and marine infrastructures such as breakwaters,
revetments and seawalls are becoming progressively abundant. Designed to withstand strong
wave action, these structures are built from large repetitive units made of stone or concrete.
Typical designs create inclined homogeneous surfaces, which compresses the intertidal zone to a
narrow vertical belt, supporting low biodiversity and often dominated by nuisance and invasive
species. In light of this, the ability of costal defense structures to provide ecosystem services
similar to those offered by natural habitats is severely compromised. Here we present a new
approach of integrating principles of Reconciliation Ecology in the design of coastal defense
structures. Results from a year-long pilot project evaluating the ability of ecologically active
armoring units, made of innovative concrete matrices and designs, to provide valuable ecosystem
services while maintaining their structural integrity and durability. This study, conducted in the
temperate waters of the Mediterranean Sea (Haifa, Israel), indicates that the combination of an
innovative ecologically active concrete mix with a complex texture and design recruits a more
diverse and dense assemblage of both benthic species and fish in comparison to standard
Portland cement armoring units. Results show a clear reduction in the dominance of invasive
species and an increased abundance of native local species, similarly to assemblages typical to
adjacent natural rocky habitats. The study demonstrates the potential ecological value of
integrating environmentally sensitive designs into coastal defense structures.
THE EXTENT AND DYNAMIC OF AQUIFER SALINIZATION NEXT TO AN
ESTUARINE RIVER
Yehuda Shalem1,2,3,Yishai Weinstein1,Eldad Levi4,5,Barak Herut2,5,Mark Goldman4 and Yoseph
Yechieli3,6
1
Bar-Ilan University, Ramat-Gan 52900, [email protected]
Israel Oceanographic and Limnological Research, Haifa 31080
3
Geological Survey of Israel, Jerusalem 95501
4
Geophysical Institute of Israel, Lod, 71700
5
Leon H. Charney School for Marine Sciences, University of Haifa, Haifa 31905
6
Ben-Gurion University of the Negev, Sede Boqer, 84990
2
Surface water-groundwater interaction occurs along the coastline and along estuarine rivers. In
particular, seawater intrusion and its impact on coastal aquifer were widely investigated.
However, seawater intrusion via estuarine rivers was hardly studied in the field. The relationships
between the sea, coastal river and groundwater were studied in a bar-built estuary (Alexander
River), which is subjected to seawater encroachment ~5km upstream. Due to the existence of
sandbar at its mouth and to the low-amplitude tides, seawater encroachment is mainly
dependent on high waves and high river discharge events which overpass and/or breach the
sandbar. Accordingly, significant stratification occurred as short event mostly during winter (1-3
times a year) with salinities at the deep layer reaching maximum values of 35‰ and 27‰, 500
and 3900 m from the shoreline, respectively. During the summer, the estuary was partially mixed,
and salinity in the bottom layer significantly decreased. Nevertheless, most of the year, typical
salinity in the deep water layer does not decreased below 6‰. The high salinity of the river
water was found to cause salinization of the shallow local aquifer in its vicinity. Both electrical
resistivity measurements methods (ERT and TDEM) and observations in shallow boreholes
suggest that the aquifer salinization is site-dependent, with the extent of salinization up to 80 m
from the river, being controlled by local geology and by hydraulic properties. Moreover, different
hydrogeological setting result different salinization pattern, in time (short and long scale) and
intensity, and react differently to changes in the river of the salinity and level. The existence of
low permeability units adjacent and below the river avoided the salinization of the regional
aquifer in the Alexander River area. Such low permeability geo-units may serve as a natural block
for future sea level rise and consequent seawater intrusion into the aquifer via coastal rivers.
AERIAL TRANSMISSION OF MARINE PHYTOPLANKTON VIRUSES
S. Sharoni1,2, M. Trainic1, D. Schatz, Y.Lehahn3, J.M. Flores1, Y. Rudich1, I. Koren1 and A.Vardi2
1
Department of Earth and Planetary Sciences, Weizmann Institute of Science, Israel
[email protected] , [email protected]
2
Department of Plant Sciences, Weizmann Institute of Science, Israel [email protected]
3
Department of Geophysics, Atmospheric and Planetary Sciences, Tel Aviv University, Israel
Marine viruses have an important role in modulating phytoplankton populations, thus playing a
key role in energy and biomass budgets in the ocean. However, the dispersal of viruses in aquatic
systems is poorly understood. Evidences show that viruses can be emitted from the ocean into
the air via wind-induced aerosol formation. However, the possibility of the air as a route of
conveying marine infective viruses has never been considered and quantitatively addressed. Here
we show that Emiliania huxleyi virus (EhV, Phycodnaviridae) that are infecting the ubiquitous,
bloom-forming phytoplankton Emiliania huxleyi, are emitted into the air such that they can
disseminate and infect neighbor healthy populations. We demonstrate in vitro that during the
infection of E. huxleyi cultures, EhVs are emitted into the air in the process of bubble bursting,
and their emission-rates are coupled to the dynamics of viral infection in the underlying cultures.
We further demonstrate that the aerosolized EhV remain infective and can be transmitted and
infect adjacent healthy cultures. These ideas are supported by i n situ analysis performed during
an E.huxleyi bloom in the North Atlantic. We found EhV-DNA footprint in aerosols, suggesting
that viral emission and transmission through the atmosphere indeed occur in the oceans. We
propose that this mechanism promotes the wide dispersal of marine viruses, contributing to
orchestrate demise events over large-scale phytoplankton blooms. Such infection mechanism
should be applicable to other marine organisms.
DYNAMICS OF CELLULAR AUTOPHAGY IN THE ACCLIMATION OF MARINE
COCOLITHOPHORES TO ENVIRONMENTAL STRESS
Adva Shemi1, Daniella Schatz1, Shilo Rosenwasser1, Shifra Ben- Dor2 and Assaf Vardi1
1
Department of Plant Sciences, The Weizmann Institute of Science, Rehovot, Israel
Department of Biological Services, The Weizmann Institute of Science, Rehovot, Israel
2
Autophagy is a eukaryotic cellular process in which, under stress conditions, cytoplasmic material
is engulfed by membrane bodies and sent to the lysosome for degradation and recycling. From
lower eukaryotes to humans, autophagy was established as an adaptive response that enhances
acclimation to stress conditions. Here, we demonstrate the cellular dynamics of autophagy and its
ecological importance in marine phytoplankton. The coccolithophore Emiliania huxleyi is a
cosmopolitan phytoplankton species that forms vast oceanic blooms that contribute greatly to
marine biogeochemical cycles. E. huxleyi blooms are terminated by specific, double stranded-DNA
giant viruses known as E. huxleyi viruses (EhV). Our in silico predictions and genomic analyses of
E. huxleyi revealed a complete core autophagy machinery, a mosaic of animal-like and plant-like
homologs, including two Atg8 proteins which are activated and converted to lipid-conjugated
forms upon autophagy induction. In order to unveil the ecological relevance of autophagy in E.
huxleyi, we exposed E. huxleyi cells to two major biotic and abiotic environmental stress
conditions and followed autophagy markers. First, infection of E. huxleyi with EhV, led to
formation of autophagic-like vesicles, expression of key autophagy–related genes and strong
lipidation of Atg8. Secondly, exposure to phosphate limitation, which is a major limiting
macronutrient in phytoplankton blooms, induced an acute autophagic response, including
lipidation of Atg8 and a unique expression pattern of specific Atg genes. However, long term
starvation led to down regulation of Atg8 and Atg7 protein levels. These results suggest that
autophagy serves as a short term acclimation machinery to increase inorganic phosphate
availability, but since it depends on protein phosphorylation and ATP, cannot be carried out under
chronic phosphate starvation. We demonstrate that autophagy is part of the response of E.
huxleyi cells to environmental stress, and plays a vital role in the life cycle of blooms in the
ocean.
THE ROLE OF CORAL REEFS IN THE CACO3 BUDGET OF THE RED SEA BASED
ON SR/CA RATIOS
Steiner Zvi1, Erez Jonathan1, Katz Amitai1, Shemesh Aldo2 and Lazar Boaz1
1
The Fredy and Nadine Herrmann Institute of Earth Sciences, The Hebrew University, Jerusalem, 91904
[email protected]
2
Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, 76100
Surface water collected in 1998 along a cruise from the northern Red Sea to the western Indian
Ocean was analyzed for salinity, major ions, total alkalinity (AT) and water isotopic composition. It
was found that the spatial distribution of δD, δ 18O and AT in Red Sea surface water was similar to
its early 1960’s patterns. This suggests that the Red Sea was at steady state with respect to its
water exchange and CaCO3 budgets between mid 1960’s and 1998. The basin-scale, net
calcification rate in the Red Sea was estimated from the alkalinity depletion along the basin. The
relative amounts of CaCO3 precipitated by calcareous plankton and corals were estimated from
the change in the spatial distribution of surface water Sr/Ca ratios. We estimate the net annual
amount of CaCO3 precipitated by Red Sea plankton to be 2∙10 11 kg. Additional 0.5∙1011 kg was
precipitated by the flourishing coral reefs. We were also able to recognize a unique hot brines
signature in Red Sea surface waters Mg content and estimate that they mix with ~8∙105 m3∙y-1
brine water. This study demonstrates that changes in major ion composition can be used to
identify CaCO3 phases precipitating at the surface ocean.
TEN-YEAR ASSESSMENT OF CHANGE IN ENVIRONMENTAL HEALTH NEAR THE
SHAFDAN OUTLET USING BENTHIC FORAMINIFERA
Tadir R. 1,2, Hyams-Kaphzan O.2, Almogi-Labin, A.2 and Benjamini C.1
1
Department of Geology and Environmental Sciences, Ben Gurion University of the Negev, Beer Sheva 84105
[email protected]; [email protected]
2
Geological Survey of Israel, Jerusalem 95501 [email protected]; [email protected]
The Israeli Mediterranean shelf is highly enriched in organic matter near the treated sewage sludge
outlet of the Shafdan, Palmahim. In a 2003-4 study living benthic foraminifera assemblages were
found responding directly to this disturbance at the polluted PL3 site 0.2 km north of the outlet,
compared with the oligotrophic control site PL29 located 5.3 km further north. The herein study
revisited those sites and added a third site, PL64, 7 km north of the outlet and 1.5 km north of PL29,
in order to track the accumulating effect of organic pollution over the last 10 years. Living (RoseBengal stained) and time-averaged dead benthic foraminifera from the top 5 cm of the sediment were
sampled at all sites in January, May, July and November 2012 together with environmental
parameters. The working hypothesis was that if sludge impact is spreading over time than organic
matter continuous overload affects living foraminifera population dynamics. Preliminary results from
winter and spring sampling show that numerical abundance of living foraminiferal species decreased
dramatically over time at both PL3 and PL29 stations, which implies a deterioration of living conditions
at both sites. This deterioration is also reflected in altered assemblage composition, with the
appearance of the opportunistic species Bolivina spp. and Hopkinsina pacifica, especially during
January. At the new distal site PL64, fewer foraminifera were found alive compared to PL29. This
might indicate that the organic pollution is spreading northward, changing PL29 to mesotrophic while
PL64 remains oligotrophic. Ammonia tepida, an opportunistic species, is the only one occurring both in
the L (living) and D (dead) assemblages, in considerable numbers. Organically-cemented agglutinants
that are common in L are rare in D because of postmortem shell fragmentation. The disparity between
L and D can be explained by environmental change overprinted by taphonomic modification of the D
assemblage.
THE CURRENT AND PAST POTENTIAL OF NATURAL METHANE HYDRATES
OCCURRENCE IN THE SOUTHEASTERN LEVANT
Tayber Z. and Makovsky Y
The Dr. Moses Strauss Department of Marine Geosciences, Leon H.Charney School of marine sciences.
Haifa University, Mt. Carmel, Haifa 31905, Israel
This research aims to define and corroborate the occurrence of Natural Methane Hydrates (NMH)
in the Eastern Mediterranean Sea (EMS), and to investigate the effects of past environmental
changes on its distribution. We begun by constructing a prediction model for the Methane
Hydrate Stability Zone (MHSZ) as a function of Pressure and Temperature (P-T) and gas
composition. Evaluating the NMH thermodynamic equilibrium conditions is routinely done either
based on extrapolation of empirical data, or based on analytical calculations of statistical
thermodynamic properties of the NMH. Comparing between the two different methods we
concluded that analytical models will give more accurate predictions of the P-T for NMH
equilibrium conditions for the relatively high temperature and salinity of the EMS. Experimenting
with different analytical models we chose the CSMHYD modeling routine of Sloan (1998), as it is
capable of predicting a relatively wide range of MHSZ. Little information exists on the in-situ
physical properties of the seafloor sediments within the Levant basin, as complete well logs have
not been acquired within the post-Messinian sequence. Thus our MHSZ prediction model for the
EMS is currently based on three basic approximations: (1) Sediments pore pressure is
hydrostatic; (2) Water temperatures and salinity at depths >0.5 km is 13.6 °C and
37.8 ‰
respectively, with no significant temporal or spatial variations; (3) The sediments temperature
increases solely due to the geothermal gradient. Our model predicts the top of pure methane
hydrates stability at a water depth of 1200 m, in agreement with the only existing evidence of
NMH stability in the EMS. Nodular NMH were cored in mud volcanos around the Anaximander
seamount, with the shallowest sample at a water depth of 1264 m. Moreover, hydrates were
recently observed forming on the surface of hydrocarbon bubbles recently collected from cold
seeps in the Nile deep sea fan, and dissociate as they were brought up to a water depth of 1350
m. This depth is in agreement with the prediction of the top MHSZ boundary of our model for the
same published gas composition. Further indirect evidences currently investigated by us for the
presence of NMH in the Levant basin include: a seemingly consistent band of high seismic
reflectivity in the shallow deep sea sediments, which seem to correlate with our predicted MHSZ;
active seafloor methane seeps at a water depth range of 1000 to1200 m, just above our
calculated edge of stability; and resistivity anomalies that seem to be observed in commercial
well logs measured while drilling. In addition we intend to simulate different assumed paleo
oceanographic conditions, which presumably prevailed in the recent geologic past, to investigate
the effect of environmental changes on the NMH in the Levant.
THE EFFECT OF SEA SURFACE TEMPERATURE AND SALINITY INCREASE ON
MARINE BENTHIC EOSYSTEMS: REVISITING THE HADERA HEAT PLUME
(ISRAEL)
Titelboim Danna1 , Abramovich Sigal 1, Almogi-Labin Ahuva 2, Herut Barak3 and Kucera Michal4
1
Department of Geological and Environmental Science, Ben Gurion University of the Negev, Beer Sheva
84105, Israel [email protected], [email protected]
2
Geological Survey of Israel, 30 Malkhe Israel, Jerusalem 95501, Israel [email protected]
3
Israel Oceanographic and Limnological Research Ltd., Tel-Shikmona, P.O.Box 8030, Haifa 31080, Israel
[email protected]
4
University of Bremen, Bremen, Germany [email protected]
The eastern most part of the Mediterranean is characterized by high salinity and temperature
values that show a gradual rise over the past few decades. This study follows a similar one
conducted in 2007 in a unique natural experimental laboratory of the Hadera power plant thermal
plume using benthic foraminifera as a model system to investigate the effects of temperature
changes. Since 2007, a desalination plant started operating in the area causing a slight increase
in salinity. The study is based on a one-year monthly ecological monitoring of living benthic
foraminifera from two stations located along the heated beach rock area and one station at a
nearby coastal control station representing normal beach rock environment. The temperature in
the plume is significantly higher than of the natural ambient water, reaching 36 ºC and 24 ºC in
summer and winter, respectively, compared to 29ºC and 17ºC in the control station. The
numerical abundances of foraminifera in the plume vary from high values in spring of ~ 300
specimens/g compared to ~ 70 specimens/g in February and July. This differs from the 2007
trends that shows overall lower values. In the control station, the numerical abundance is 5-7
times higher in winter and summer and only 2 times higher in spring. Species diversity is higher
in the control station than in the polluted ones throughout the year and especially in summer.
The assemblage composition in the plume hardly changed with time and the dominating genera
are Lachlanella, Pararotalia and Tretomphalus. Pararotalia, a symbiont bearing species, has high
tolerance to high temperatures and is living in the heated plume even in the most extreme
summer months. It appears that this species can survive up to 35ºC while other species leaving
in the plume can only tolerate 30ºC.
NONLINEAR BROADENING OF NEAR-SHORE WAVE SPECTRA
Yaron Toledo1, Jacoo Groeneweg2, Marcel van Gent2, Joana van Nieuwkoop2, Teodor Vrecica1
1
School of Mechanical Engineering, Tel-Aviv university, Tel-Aviv 6997801, Israel
[email protected], [email protected]
2
Deltares, P.O. Box 177, 2600 MH Delft, The Netherlands
[email protected], [email protected], [email protected]
Nonlinear wave interactions have a significant effect on the wave spectra in the near-shore
region. And yet, their calculation still poses significant modeling challenges. Deterministic
nonlinear models that account for these interactions are numerically expensive, and hence mostly
used for limited computation areas that results in losing a significant part of the spectral
evolution effects. Stochastic phase-averaged wave models are commonly use for this purpose as
they are efficient enough for resolving large enough computation areas. Nevertheless, they
consist of an approximate 1D formulation of the governing wave-triad interactions. In the
presented work, the 2D triad interaction mechanism is investigated in cases of sharp changes in
the bottom slope using a nonlinear oblique parabolic equation model and a Boussinesq model.
Using these models a fundamental type of nonlinear triad interaction responsible for broadening
the primary wave harmonic in the spectrum is identified. This mechanism is explained for the
simple case of two similar monochromatic waves propagating in different attack angles over a
slope ending with a plateau. It shows nonlinear energy transfer to waves of the primary
harmonic that approach at larger attack angles than the originating waves countering linear
shoaling intuition. The importance of this nonlinear effect is examined for waves propagating
toward a channel. Laboratory experiments were acquired and compared to computations of the
Boussinesq model and the phase-averaged SWAN model, which consists of a common limited
super-harmonic triad self-interaction source term. These comparisons demonstrated that the
absence of the 2D interactions in SWAN is causing an unrealistic amount of energy to be trapped
on the channel slopes due to wave refraction. The 2D nonlinear interactions broaden the
directional range of the energy density spectrum when waves propagate over a sloping bottom.
It results in a larger amount of wave energy transmitted into and across channels.
THE U-SERIES TOOLBOX IN MODERN AND PALEO- OCEANOGRAPHY:
FROM A DAILY TO MILLION YEAR TIMESCALE TRACER OF MARINE FLUXES
Adi Torfstein1,2
1
Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel [email protected]
Interuniversity Institute for Marine Sciences, Eilat 88103, Israel
2
Knowledge of the timescales of natural processes that take place on the surface of Earth, and in
particular in ocean waters and sediments, is a prerequisite for understanding the interplay
between geology, biology and chemistry in the modern and past oceans. The Uranium (and
Thorium) decay chains form a series of radionuclides with various half lives that cover the entire
spectrum between billions of years to minutes (and less). Combined with significant differences in
the chemical properties between each of the radionuclides, these series provide a unique
temporal monitor of many critical processes, including rock formation and sediment deposition
ages, fluxes of organic and inorganic material from the continents into (and within) the oceans,
rates of submarine groundwater discharge into the ocean, modern and paleo- ocean circulation,
rates of oceanic primary productivity and formation of “marine snow”, rates of particle dissolution
in the oceans (e.g., dust), and many others. In this talk I will present an overview of the
governing principles and methods used for the application of U-decay series in oceanographic
studies. I will further discuss recent examples for such applications from Antarctica and the Red
Sea, two of the most extreme desert environments on Earth, and will present current applications
of U-decay series in the Gulf of Eilat.
OUR EYES BENEATH THE SEA: ADVANCED OPTICAL METHODS FOR OCEAN
IMAGING
Tali Treibitz
Charney School of Marine Sciences, University of Haifa [email protected]
The ocean is a complex, vast, foreign environment that is hard to explore and therefore much
about it is still unknown. Interestingly, only 5% of the ocean floor has been seen so far. As
human access to most of the ocean is very limited, optical imaging systems can serve
as our eyes in those remote areas. However, optical imaging underwater is challenging due to
strong color and distance dependent attenuation, scattering, refraction at the interface air/water,
and the ever-changing and rugged conditions of the natural ocean. Thus, imaging underwater
pushes optical imaging to its limits. This is where advanced computer vision methods may
overcome some of these obstacles post-acquisition and enable large-scale operations using
machine learning.
As a result, imaging systems for the ocean require a dedicated effort throughout all the
development steps: design, optical, electrical and mechanical engineering and computer vision
algorithms. In this work I describe several in situ underwater imaging systems I developed and
show how they can be used to solve acute scientific problems. These include an underwater in
situ high-resolution microscope for plankton and corals, underwater 3D reconstruction, and
systems for large-scale multispectral and fluorescence imaging.
MICROPLASTIC POLLUTION AND ITS POTENTIAL EFFECTS ON MARINE BIOTA
IN ISRAELI COASTAL WATERS
Noam van der Hal1 and Dror Angel2
Department of Maritime Civilizations and Recanati Institute for Maritime Studies, University of Haifa, Haifa
31905 [email protected], [email protected]
Micro-plastics (<5mm plastic debris) are found throughout the world's oceans and have been
recognized as a major form of pollution which may potentially threaten marine food webs. A new
research project on the abundances and characteristics of micro-plastic particles in Israeli
Mediterranean coastal waters was launched in summer 2013. Sea surface samples were collected
by means of a Manta net that samples the upper 20cm of the sea, and shallow seafloor sediment
samples were taken at the same stations, by means of sediment cores, by SCUBA divers.
Seasonal sampling over the course of 18 months at a fixed set of stations along the coast should
enlighten us on the state of micro-plastic debris along our Mediterranean shores. Characterization
of the micro-plastic particles includes an initial record of the type, size, shape and color of this
synthetic material. This will be followed by FTIR examination of a subset of particles to identify
the type of polymer the particles are composed of. We also plan to investigate whether these
small particles are ingested by marine biota, by inspecting gut contents, and by means of
laboratory observations. In addition, we would like to understand if these particles adsorb marine
pollutants (mainly synthetic organic compounds) which may then impact the biota that ingest
these.
POLYCLAD FLATWORMS (PLATYHELMINTHES: RHABDITOPHORA) FROM EILAT
ROCKY SHORE (GULF OF AQABA, ISRAEL)
Ximena Velásquez 1, Yehuda Benayahu 1 and D. Marcela Bolaños 2
1
Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978.
[email protected] , [email protected]
2
Programa de Biología, Facultad de Ciencias Exactas y Naturales, Universidad de Cartagena, Cartagena,
Colombia. [email protected]
Free-living polyclad flatworms are a diverse order globally distributed in the marine environment,
mainly occupying rocky shores and coral-reef habitats. Although, polyclads are important mobile
predators on the intertidal zone and appear to have close association with other invertebrates, no
comprehensive taxonomic surveys exist for the Eilat coast. In order to advance our knowledge of
polyclad flatworms, we described, indentified and examined the abundance of the species inhabiting
this region. Sampling was performed in a belt transect divided in 16 quadrants of
1.5 x 1.5 m,
randomly placed on the rocky shore at the Inter-University Institute for Marine Science (IUI), during
2013. Each quadrant was surveyed during five minutes and all specimens encountered were counted.
The specimens collected were fixed in frozen 10% formalin and transferred to 70% ethanol for
histological preparation. The reproductive structures were dissected, embedded in paraffin and
sagittal sections were prepared (6 µm). These were stained with hematoxylin-eosin, mounted in
Permount on glass slides and observed under a microscope. The internal anatomy of the male and
female reproductive systems was analyzed and identifications were made following the taxonomic
key of Faubel (1983-1984).The abundance and relative abundance of the worms were calculated and
the significant differences between the sampled months were tested using ANOVA. A total of 410
polyclad specimens were record during the sampling belonging to seven families and nine genera.
The suborder Acotylea was represented by three families (Pleoplanidae, Notoplanidae, Planoceridae)
and
three
genera
(Persica,
Notoplana,
Paraplanocera)
while
Cotylea
by
four
families
(Prosthiostomidae, Pseudocerotidae, Boniniidae and Euryleptidae) and six genera ( Prosthiostomum,
Enchiridium, Pseudobiceros, Thysanozoon, Boninia and Eurylepta). All the species are new records
for Eilat, and thus contribute to the knowledge on the biodiversity of polyclad flatworms of the
region. In terms of relative abundance, the abundant genera were Persica (65.85%) and Notoplana
(27.32%). The polyclads abundance not exhibit any distinct monthly fluctuations, yet was a bit
higher in August.
SEDIMENT CHARACTERIZATION AT THE DISTAL PART OF THE NILE LITTORAL
CELL AND BEYOND USING SEDIMENT TRAPS AND SURFACE SEDIMENTS
Danielle Vital1,3, Revital Bookman1, Ahuva Almogi-Labin2 and Barak Herut1,3
1
Dr. Moses Strauss Department of Marine Geosciences, Charney School of Marine Sciences, University of
Haifa, Mount Carmel, Haifa 31905, Israel [email protected], [email protected],
2
Geological Survey of Israel, Jerusalem 9550161, Israel [email protected]
3
Israel Oceanographic and Limnological Research, Haifa 31080, Israel [email protected]
The 650 km Nile Littoral Cell extends between the Abu Quir Bay near Alexandria, Egypt in the
south-west, and the Haifa Bay in the north-east. Siliciclastics sediments that reach the Israeli
shoreline are transported from the Nile Delta by the anticlockwise long shore current that flows
along the southeastern Mediterranean shores with a net north direction. The percentage of
siliciclastics sediments decreases northward, while the percentage of biogenic sediments
increases. During the last few decades, the modern Nile littoral cell is influenced by natural and
significant anthropogenic changes. The impact of such changes is best visible at Haifa Bay, the
most distal part within the Nile Cell, an area chosen for this study. In this research, the
characterization of sediments carried by the currents is determined by deploying sediment traps
in the vicinity of Haifa Bay at: 1. offshore 'Dadu' beach, south of Haifa Bay; 2. offshore north of
the Carmel headline; 3. offshore Shavei Tzion at the northernmost part of the Israeli coast, all
traps at 15 m water depth. Sediment dynamics, sedimentation rates and fluxes, grain size
distribution, chemical composition and quartz grain morphology are determined for the
suspended fraction sampled by the traps and also in surface sediments underlying the traps. The
current results show a monthly spatial variability of the above mentioned parameters. Future
examination of sediment cores and comparison with the traps data is expected to depict the
influence of the longshore currents on different sedimentological properties. Having a better
understanding of the sedimentological behavior in a high scale temporal resolution, will assist in
understanding the long-term deposition processes in the distal Nile littoral cell.
INORGANIC CACO3 PRECIPITATION AND PO43- ADSORPTION ON SUSPENDED
SOLIDS IN THE GULF OF AQABA (EILAT)
Eyal Wurgaft1, Zvika Steiner1, Murielle Dray2, Tanya Rivlin2, Jonathan Erez1, Boaz Luz1 and
Boaz Lazar1
1
The Fredy and Nadine Herrmann Institute of Earth Science, The Hebrew University of Jerusalem, Israel,
[email protected]
2
The Interuniversity Institute for Marine Science in Eilat, Israel
The deep-water alkalinity of the oceans is usually higher than that of surface-water, due to CaCO3
dissolution. In the Gulf of Aqaba, on the other-hand, surface-water alkalinity is higher than that
of deep-water. A time-series of alkalinity and nutrients measurements from the Gulf shows a slow
and gradual decrease in alkalinity below the thermocline, superimposed by abrupt events of
alkalinity drop. Some of these events also showed a decrease in PO33- with no corresponding
“Redfieldian” drop in NO3-. Based on these observations, we hypothesized that solids suspended
in the water column acted as precipitation nuclei for inorganic CaCO 3, and as PO43- adsorption
sites. To test this hypothesis we conducted CaCO3 precipitation experiments, using precipitation
nuclei comprised of deep-water bottom sediments, near-shore sediments and corals’ powder
suspended in Gulf’s seawater. All experiments showed alkalinity drop compared to the control,
indicating inorganic CaCO3 precipitation. PO34- decreased in the precipitation experiments with
corals’ powder and near-shore sediments indicating adsorption. The experiment with bottom
sediments, however, showed PO34- increase, probably due to release of adsorbed PO34-. Our field
observations and laboratory experiments suggest that two mechanisms are responsible for the
low alkalinity observed in the deep-water column of the Gulf: 1. biological CaCO3 deposition in
the surrounding coral-reefs; and 2. inorganic CaCO3 precipitation on suspended nuclei.
Accordingly, we suggest that suspended particles may induce inorganic CaCO 3 precipitation in the
world ocean, a process which may be an overlooked factor in the marine carbon cycle.
POST-TRANSCRIPTIONAL REGULATION OF GENE EXPRESSION IN CNIDARIA
AND WHAT IT CAN TEACH US ABOUT ANIMAL EVOLUTION
Yehu Moran
Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of
Science, Hebrew University of Jerusalem, Jerusalem 91904, Israel, [email protected]
Cnidaria (sea anemones, corals, hydras and jellyfish) are the sister group of Bilateria, which
comprise the vast majority of extant animals. In recent years it was shown that cnidarians have
gene families and genome architecture surprisingly reminiscent of those of bilaterians. Moreover,
cis-regulation of transcription is very similar in cnidarians and bilaterians. These findings are in
striking contrast to the vastly different body plans and cell type compositions of Cnidaria and
Bilateria. An attractive hypothesis is that differences in post-transcriptional regulation may explain
this apparent contradiction. In bilaterians microRNAs (miRNAs) regulate the majority of
messenger RNAs (mRNAs) via base-pairing of a short sub-sequence (the miRNA “seed”) to their
target, subsequently promoting translational inhibition and transcript instability. In contrast, most
plant miRNAs guide endonucleolytic cleavage of highly complementary targets. As little is known
about miRNA function in non-bilaterian animals, we investigated the repertoire and biological
activity of miRNAs in the sea anemone Nematostella vectensis. Our work uncovered tens of novel
miRNAs in Nematostella, increasing the total miRNA gene count to 88, yet only a handful of them
seem to be conserved in corals and hydras. This suggests that miRNA gene turnover in Cnidaria
might be much higher than in other animal groups. Further, Nematostella, miRNAs frequently
direct the cleavage of their targets via nearly perfect complementarity extending beyond the
seed. This mode of action is reminiscent of that of small interfering RNAs (siRNAs) and plant
miRNAs. It appears to be common to Cnidaria, as several of the miRNA target sites are conserved
among distantly related sea anemone species and since we also detect miRNA-directed cleavage
in the far-related cnidarian Hydra. Moreover, unlike in bilaterians, Nematostella miRNAs are
commonly co-expressed with their target transcripts. Thus, we propose that post-transcriptional
regulation by miRNAs functions very differently in Cnidaria and Bilateria. The similar, siRNA-like
mode of action of miRNAs in Cnidaria and plants suggests that this is an ancestral evolutionary
state.
‫כיצד משפיעים אירועי עקה על מרכיבים שונים בחברה האקולוגית בטבלאות‬
‫הגידוד לנוכח שינוי אקלים גלובלי?‬
‫רעות זמיר‪ ,‬פינחס אלפרט וגיל רילוב‬
‫טבלאות הגידוד שלאורך חופי ישראל הינם בית גידול ייחודיי‪ ,‬בעל מגוון רב של מיני אצות ובעלי‬
‫חיים כגון סרטנים‪ ,‬חלזונות וחסרי חוליות אחרים‪ .‬בית גידול זה המצוי על הקו המפריד בין הים‬
‫ליבשה‪ ,‬נתון לפיכך לעקות סביבתיות קשות הכוללות מפץ גלים וסערות‪ ,‬חום כבד ויובש‪ .‬בעלי‬
‫החיים וחברת האצות המאכלסים את בית הגידול‪ ,‬אמורים להיות בעלי היכולת להתמודד אל מול‬
‫עקות אלה‪ .‬אך מה טומן עתידם במקרה של החמרה בעוצמה ובתדירות העקות הסביבתיות? על פי‬
‫תחזיות שינוי אקלים בישראל‪ ,‬תנאי עקה וקיצון יתרבו ויתחזקו בעתיד ולכן חשוב להבין מה מתרחש‬
‫בבית הגידול‪ ,‬על מנת שנוכל לחזות מה יהיו השינויים העתידיים‪ .‬מחקר זה בא להגדיר ולאפיין את‬
‫אירועי העקה החריגים בטבלאות הגידוד ולבחון את השפעתם האקולוגית ותדירותם של אירועי‬
‫אקלים חריגים על מנת לתת תחזית קדימה לגורלו של בית הגידול ל‪ 41 -‬השנים הבאות‪ .‬לעיתים‬
‫מתרחשות בישראל מכות חום ממושכות בשילוב רצף ימים של רוחות מזרחיות ברצועת החוף אשר‬
‫חושפות את הטבלאות לאוויר ומייבשות אותן לחלוטין‪ .‬רוחות מזרחיות חזקות מורידים את מפלס‬
‫הים אל מתחת לקו הטבלאות‪ ,‬גם בזמן גאות‪ ,‬וחושפים את הטבלאות לאוויר מדברי יבש ‪ ,‬קרינה‬
‫חזקה‪ ,‬וטמפרטורות גבוהות לאורך זמן‪ .‬השפעתו של אירוע כזה עלולה להיות קריטית לחיים על‬
‫הטבלאות‪ .‬את ה פגיעה בבית הגידול ניתן לראות בבירור בימים של רוחות מזרחיות ויובש בהם כל‬
‫חברת האצות עוברת תהליך של הלבנה (‪ )bleaching‬ומספרם של בעלי החיים המאכלסים את‬
‫הטבלה יורד באופן משמעותי‪ .‬ימים אלה יכולים להמשך עד כשבוע באופן רציף ואף יותר‪ .‬מעקב‬
‫אחר התנאים הסינופטיים בחוף לאורך השנים בשילוב איסוף נתונים ותצפיות בשטח‪ ,‬מראה כי‬
‫באירועים של עקת יובש שוררות לרוב אחת משתי מערכות אקלימיות בולטות בשם אפיק ים סוף‬
‫ואפיק פרסי רדוד‪ .‬בתקופות אלה‪ ,‬בנוסף להלבנת האצות (‪,)bleaching‬מתקיימת ירידה משמעותית‬
‫בביומאסה שלהן‪ ,‬ובמקרים קיצוניים תמותה של בעלי חיים‪ .‬לצורך השלמת הממצאים אבצע‬
‫במקביל ניסויי מעבדה הבוחנים את רגישותם של מיני אצות ספציפיים לתנאי יובש ולבסוף בעזרת‬
‫מודל אקלימי נבדוק האם התרחש שינוי בתדירותם ובעוצמתם של נתוני האקלים שנמצאו כחריגים‬
‫בשנים האחרונות‪ ,‬ובשילוב תוצאות הניסוי והתצפיות ננסה לקבוע את עתידו של בית הגידול‪.‬‬
SPRING BLOOM INITIATION AFTER UNUSUALLY DEEP WINTER MIXING:
BLOOM DYNAMICS IN THE GULF OF AQABA
Margarita Zarubin1,2,*, Yoav Lindemann1,3,* and Amatzia Genin1,2
1
The Interuniversity Institute for Marine Sciences, POB 469, 88103 Eilat, Israel
[email protected]; [email protected]; [email protected]
2
Department of Ecology, Evolution and Behavior, Silberman Institute of Life Sciences, the Hebrew
University of Jerusalem, Jerusalem 91904, Israel.
3
Department of Earth Sciences, the Hebrew University of Jerusalem, Jerusalem 91904, Israel.
*
These authors contributed equally to the study.
Sverdup’s Critical Depth Hypothesis posits that vernal phytoplankton blooms are caused by
enhanced growth rates in response to improved light, temperature and stratification conditions.
Long-term observations are not compatible with Sverdup’s proposed mechanism. Suggesting to
abandon this hypothesis, Behrenfeld (2010) proposed in its place the “Dilution-Recoupling
Hypthesis”. We tested this hypothesis in the Gulf of Aqaba, Red Sea - a gulf exhibiting a very
deep winter mixing (exceeding 500 m) - by sampling seawater twice a month during the mixed
layer deepening and measuring the grazing rates using the dilution technique during two winters.
We found that the grazing rates did not decrease with increasing mixing depth. No dilution effect
could be observed and our results do not support the Dilution-Recoupling Hypothesis. Conversely,
the analysis of an extensive data set collected in the past decade by the National Monitoring
Program reveals a close correspondence between the bloom dynamics and changes in nutrient
concentration. The apparent underlying mechanism will be discussed.
ON NON-BOUSSINESQ GRAVITY CURRENTS IN NON-RECTANGULAR CROSSSECTION CHANNELS
Tamar Zemach
Department of Computer Science, Tel-Hai College, Tel-Hai, Israel ,[email protected]
A gravity current (GC) appears when fluid of one density, ρc , spreads into a fluid of another
density, ρa , and the propagation is, mainly, in the horizontal direction. Gravity currents occur at
a variety of scales throughout nature. Examples include oceanic fronts, avalanches, seafloor
turbidity currents, pyroclastic flows and lava flows. Most studies have focused on the flow of
currents that propagate on the flat bottom (or top) of a rectangular channel. If the Reynolds
number (Re) is large (as assumed here), the lateral boundaries of such a container are
unimportant. However, GCs generated and spreading in channels with non-rectangular crosssections are realistic configurations in nature (e.g. valleys and rivers), buildings, irrigation
systems and industrial fluid-transport infrastructures. It is therefore of both practical and
academic importance to understand and model the effects of the inclined or curved sidewalls of
the channel on the flow of the GC. The investigation of the flow field of high-Re GCs in channels
with non-rectangular cross-sections is a relatively new topic. In the present work we consider the
propagation of a gravity current of density ρc from a lock length x0 and height h0 into an
ambient fluid of density ρa in a horizontal channel of height H along the horizontal coordinate x.
The bottom and top of the channel are at z = 0, H, and the cross-section is given by the quite
general − f1 (z) ≤ y ≤ f2 (z) for 0 ≤ z ≤ H. When the Reynolds number is large, the resulting
flow is governed by the parameters R = ρc /ρa , H* = H/h0 and f (z) = f1 (z) + f2 (z). We show
that the shallow-water one-layer model, combined with a Benjamin-type front condition, provides
a versatile formulation for the thickness h and speed u of the current. The results cover in a
continuous manner the range of light ρc /ρa < 1, Boussinesq ρc /ρa ≈ 1 and heavy ρc /ρa>1
currents in a fairly wide range of depth ratio in various cross-section geometries. We obtain
analytical solutions for the initial dam-break stage of propagation with constant speed, which
appears for any cross-section geometry, and derive explicitly the trend for small and large values
of the governing parameters. For large time, t, a self-similar propagation is feasible for f (z) =
bzα cross-sections only, with t (2+2α)/(3+2α) . The present approach is a significant
generalization of the classical non-Boussinesq gravity current problem. The classical formulation
for a rectangular (or laterally unbounded) channel is now just a particular case, f (z) = const., in
the wide domain of cross-sections covered by this new model.