Distributions, trends and inter-annual variability of nutrients along a repeat section through the Weddell Sea (1996–2011)

NARCIS (Netherlands)

Hoppema, M.; Bakker, K.; van Heuven, S.; van Ooijen, J.C.; de Baar, H.J.W.

2015-01-01

Nutrient data from five repeat sections spanning 1996 to 2011 crossing the Weddell Sea are presented. These measurements have been standardized against the same reference material, yielding an outstanding internal consistency. The generic structure of the Weddell Gyre and its hydrographic features

Past and present stability of the Weddell Sea sector of the Antarctic Ice Sheet

Science.gov (United States)

Whitehouse, P. L.; Vieli, A.; Jamieson, S.; Bentley, M.; Hein, A.; Sugden, D.

2016-12-01

The contribution of the Weddell Sea sector of the Antarctic Ice Sheet to sea-level rise since the Last Glacial Maximum (LGM), along with the processes controlling the past and ongoing dynamics of this sector, are poorly known. Of particular concern is the fact that significant portions of the present-day grounding line are unstably located on bathymetry that deepens towards the interior of the continent. We present new modelling results, constrained by field evidence relating to past ice extent and thickness along the Foundation Ice Stream and Thiel Trough, which suggest that the post-LGM sea-level contribution from this sector was modest, and that the grounding line is unlikely to have been located at the continental shelf break for a prolonged period during the last glacial cycle. Poorly-constrained ice shelf and ocean processes are found to play a crucial role in controlling the past configuration and stability of this sector of the ice sheet. In particular, we find that we cannot rule out a scenario in which the grounding line of the Foundation Ice Stream retreated behind present during deglaciation, and has since re-advanced. This work complements a number of recent studies, based on independent data sets, that explore the possibility that grounding line re-advance occurred within the Weddell Sea sector during the mid-to-late Holocene. If this hypothesis is correct, then current glacial isostatic adjustment models, and hence contemporary estimates of ice mass balance derived from GRACE data, will be significantly biased. Piecing together, and understanding, the reason for recent changes in ice dynamics is crucial for determining the contemporary stability of the Weddell Sea sector of the Antarctic Ice Sheet.

Three new species of deep-sea Gromia (Protista, Rhizaria) from the bathyal and abyssal Weddell Sea, Antarctica

DEFF Research Database (Denmark)

Rothe, Nina; Gooday, Andrew J.; Cedhagen, Tomas

2009-01-01

We describe three new species of the genus Gromia from bathyal and abyssal depths in the Weddell Sea. The new species are characterized by a combination of morphological and molecular criteria. All three species possess a distinct oral capsule and a layer of ‘honeycomb membranes’, which form the ...

ICESat Observations of Seasonal and Interannual Variations of Sea-Ice Freeboard and Estimated Thickness in the Weddell Sea, Antarctica (2003-2009)

Science.gov (United States)

Yi, Donghui; Robbins, John W.

2010-01-01

Sea-ice freeboard heights for 17 ICESat campaign periods from 2003 to 2009 are derived from ICESat data. Freeboard is combined with snow depth from Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) data and nominal densities of snow, water and sea ice, to estimate sea-ice thickness. Sea-ice freeboard and thickness distributions show clear seasonal variations that reflect the yearly cycle of growth and decay of the Weddell Sea (Antarctica) pack ice. During October-November, sea ice grows to its seasonal maximum both in area and thickness; the mean freeboards are 0.33-0.41 m and the mean thicknesses are 2.10-2.59 m. During February-March, thinner sea ice melts away and the sea-ice pack is mainly distributed in the west Weddell Sea; the mean freeboards are 0.35-0.46 m and the mean thicknesses are 1.48-1.94 m. During May-June, the mean freeboards and thicknesses are 0.26-0.29 m and 1.32-1.37 m, respectively. The 6 year trends in sea-ice extent and volume are (0.023+/-0.051) x 10(exp 6)sq km/a (0.45%/a) and (0.007+/-1.0.092) x 10(exp 3)cu km/a (0.08%/a); however, the large standard deviations indicate that these positive trends are not statistically significant.

New data on Weddell seal (Leptonychotes weddellii colonies: A genetic analysis of a top predator from the Ross Sea, Antarctica.

Directory of Open Access Journals (Sweden)

Ighor Antunes Zappes

Full Text Available In this paper, we studied the genetic variability in Weddell seal from colonies in Terra Nova Bay and Wood Bay, both sites located in the Ross Sea area, Antarctica. Two mitochondrial genes and one nuclear gene, with different mutation rates, were sequenced to investigate the haplotype diversity of the colonies and to test for a possible recent expansion. Fifteen microsatellites were used to analyze their genetic structure. Sequenced genes and microsatellites were also used to estimate the effective population size of the studied colonies and the Ross Sea seal population. The Ross Sea has a high density population of Weddel seals, with an estimated effective number of 50,000 females, and 1,341 individuals for the sampling area, possibly due to its high primary production. The colonies showed high diversity (Hd > 0.90 and many exclusive haplotypes (> 75%, likely a consequence of the surprisingly high site fidelity of Weddell seals, despite the proximity of the colonies. Nevertheless, there was low microsatellite differentiation between colonies, suggesting that they are part of a single larger population. Their expansion seemed to have started during the last glacial cycle (around 58,000 years ago, indicating that the Ross Sea seal populations have been present in the area for long time, probably due to the lack of hunting by humans and terrestrial predation. As a top predator, the role of Weddell seals in the Ross Sea ecology is crucial, and its demographic dynamics should be monitored to follow the future changes of such an important ecosystem.

A rapid transition from ice covered CO2–rich waters to a biologically mediated CO2 sink in the eastern Weddell Gyre

Directory of Open Access Journals (Sweden)

W. Geibert

2008-09-01

Full Text Available Circumpolar Deep Water (CDW, locally called Warm Deep Water (WDW, enters the Weddell Gyre in the southeast, roughly at 25° E to 30° E. In December 2002 and January 2003 we studied the effect of entrainment of WDW on the fugacity of carbon dioxide (fCO2 and dissolved inorganic carbon (DIC in Weddell Sea surface waters. Ultimately the fCO2 difference across the sea surface drives air-sea fluxes of CO2. Deep CTD sections and surface transects of fCO2 were made along the Prime Meridian, a northwest-southeast section, and along 17° E to 23° E during cruise ANT XX/2 on FS Polarstern. Upward movement and entrainment of WDW into the winter mixed layer had significantly increased DIC and fCO2 below the sea ice along 0° W and 17° E to 23° E, notably in the southern Weddell Gyre. Nonetheless, the ice cover largely prevented outgassing of CO2 to the atmosphere. During and upon melting of the ice, biological activity rapidly reduced surface water fCO2 by up to 100 μatm, thus creating a sink for atmospheric CO2. Despite the tendency of the surfacing WDW to cause CO2 supersaturation, the Weddell Gyre may well be a CO2 sink on an annual basis due to this effective mechanism involving ice cover and ensuing biological fCO2 reduction. Dissolution of calcium carbonate (CaCO3 in melting sea ice may play a minor role in this rapid reduction of surface water fCO2.

Bacterial Standing Stock, Activity, and Carbon Production during Formation and Growth of Sea Ice in the Weddell Sea, Antarctica †

OpenAIRE

Grossmann, Sönnke; Dieckmann, Gerhard S.

1994-01-01

Bacterial response to formation and growth of sea ice was investigated during autumn in the northeastern Weddell Sea. Changes in standing stock, activity, and carbon production of bacteria were determined in successive stages of ice development. During initial ice formation, concentrations of bacterial cells, in the order of 1 × 108 to 3 × 108 liter-1, were not enhanced within the ice matrix. This suggests that physical enrichment of bacteria by ice crystals is not effective. Due to low conce...

New high-resolution record of Holocene climate change in the Weddell Sea from combined biomarker analysis of the Patriot Hills blue ice area

Science.gov (United States)

Fogwill, Christopher; Turney, Chris; Baker, Andy; Ellis, Bethany; Cooper, Alan; Etheridge, David; Rubino, Mauro; Thornton, David; Fernando, Francisco; Bird, Michale; Munksgaard, Niels

2017-04-01

We report preliminary analysis of biomarkers (including dissolved organic matter (DOM) and DNA) from the Patriot Hills blue ice area (BIA), from the Ellsworth Mountains in the Weddell Sea Embayment. Preliminary isotopic and multiple gas analysis (CO2, CH4, N2O and CO) demonstrate that the Holocene comprises more than 50% of the 800m long BIA record, and in combination isotopic and biomarker analysis reveals a remarkable record of centennial variability through the Holocene in this sector of the Weddell Sea. Analysis using a Horiba Aqualog - which measures the fluorescence of DOM by producing a map of the fluorescence through an excitation-emission matrix (EEM) - identifies the presence of two marine protein-like components in both modern snow pit samples and within the Holocene part of Patriot Hills BIA transect. Intriguingly, the modern seasonal trends in DOM, recorded in contemporary snow pits, have relatively low signals compared to those recorded in the mid-Holocene record, suggesting a reduction in DOM signal in contemporary times. Given that the δD excess data suggests the source of precipitation has remained constant through the Holocene, the biomarker signal must relate to multi-year marine productivity signals from the Weddell Sea. The marked variability in DOM between the mid-Holocene and contemporary times can only relate to periods of sustained, enhanced biological productivity in the Weddell Sea associated with shifts in Southern Annular Mode, sea ice variability, changes in ventilation or polynya activity. Here we discuss the possible drivers of these changes and describe how this approach at this BIA could benefit conventional ice core records regionally.

Low post-glacial rebound rates in the Weddell Sea due to Late Holocene ice-sheet readvance

Science.gov (United States)

Bradley, Sarah L.; Hindmarsh, Richard C. A.; Whitehouse, Pippa; Bentley, Michael J.; King, Matt

2014-05-01

The Holocene deglaciation of West Antarctica resulted in widespread ice surface lowering. While many ice-sheet reconstructions generally assume a monotone Holocene retreat for the West Antarctica Ice sheet (WAIS) [Ivins et al., 2013; Peltier, 2004; Whitehouse et al., 2012], an increasing number of glaciological observations infer it is readvancing, following retreat behind the present-day margin[Siegert et al., 2013]. We will show that a readvance in the Weddell Sea region can reconcile two outstanding problems: (i) the present-day widespread occurrence of seemingly stable ice-streams grounded on beds that deepen inland in apparent contradiction to theory [Schoof, 2007]; and (ii) the inability of models of Glacial Isostatic Adjustment (GIA) to match present-day uplift rates [Whitehouse et al., 2012]. Combining a suite of ice loading histories that include a readvance with a model of GIA provides significant improvements to predictions of present-day uplift rates, and we are able to reproduce previously unexplained observations of subsidence in the southern sector of the Weddell Sea. We hypothesize that retreat behind present grounding lines occurred when the bed was lower, and isostatic recovery led to shallowing, ice sheet re-grounding and readvance. We will conclude that some sections of the current WAIS grounding line that are theoretically unstable, may be advancing and that the volume change of the WAIS may have been more complex in the Late Holocene than previously posited. This revised Holocene ice-loading history would have important implications for the GIA correction applied to Gravity Recovery and Climate Experiment (GRACE) data, likely resulting in a reduction in the GIA correction and a smaller estimate of present-day ice mass loss within the Weddell Sea region of the WAIS. Ivins, E. R., T. S. James, J. Wahr, E. J. O. Schrama, F. W. Landerer, and K. M. Simon (2013), Antarctic contribution to sea level rise observed by GRACE with improved GIA correction

Fluxes of dissolved aluminum and manganese to the Weddell Sea and indications for manganese co-limitation

NARCIS (Netherlands)

Middag, R.; de Baar, H.J.W.; Klunder, M.B.; Laan, P.

2013-01-01

The trace metals aluminum (Al) and manganese (Mn) were studied in the Weddell Sea in March 2008. Concentrations of dissolved Al ([Al]) were slightly elevated (0.23-0.35 nmol L-1) in the surface layer compared to the subsurface minimum (0.07-0.21 nmol L-1) observed in the winter water. Atmospheric

Physical and chemical data collected using bottle casts from the GENERAL SAN MARTIN in the Scotia Sea and Weddell Sea from 14 December 1963 to 11 January 1964 (NODC Accession 0000791)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Physical and chemical data were collected using bottle casts in the Scotia Sea and Weddell Sea from the GENERAL SAN MARTIN. Data were collected from 14 December 1963...

Phase and amplitude Variation of Weddell Sea Anomaly at King Sejong Station in Antarctic between 2005 and 2009

Science.gov (United States)

Chung, J.; Lee, C.; Jee, G.

2011-12-01

The Weddell Sea Anomaly (WSA) in ionosphere has been defined by higher electron density at nighttime than during the daytime on summer season near the region of the Weddell Sea.Recent studies show the WSA is an extreme case of longitudinal variation and occurrs all of season except for winter when F10.7 is high. We examine the temporal variation of the WSA using the ground-based GPS TEC measured King Sejong station (geographic latitude 62.2°S, longitude 58.5°W, corrected geomagnetic latitude 48°S) in Antarctic between 2005 and 2009 in condition of solar minimum. We analyze the characteristics of diurnal and semi-diurnal variation for all of years and examine the yearly and seasonal variation of phase and amplitude of the WSA. Our results of local time GPS TEC variation show the amplitudes of the WSA are significant in the summer and its phases appear to be changed according to the season.

Effect of UV-B irradiance on the ATP content of microorganisms of the Weddell Sea (Antartica)

International Nuclear Information System (INIS)

Vosjan, J.H.; Nieuwland, G.; Doehler, G.

1990-01-01

The effect of UV-B irradiation on the ATP content of natural assemblages of planktonic microorganisms in the upper 30-m water layer of the Weddell Sea (Antartica) was studied. After five hours of irradiation with UV (290-320 nm) of 1.35 W.m -2 a 75% decrease in the ATP content of the microorganisms was observed. (author). 11 refs.; 3 figs

Basic epidemiological data on metazoan parasites of notothenioid fish off James Ross Island (Prince Gustav Channel, Weddell Sea), Antarctica

Czech Academy of Sciences Publication Activity Database

Nezhybová, Veronika; Mašová, Š.

2015-01-01

Roč. 5, č. 1 (2015), s. 44-54 ISSN 1805-0689 R&D Projects: GA ČR(CZ) GBP505/12/G112 Institutional support: RVO:68081766 Keywords : Host * Notothenioid fish * Parasites * Prince Gustav Channel * Weddell Sea Subject RIV: EG - Zoology

Effect of UV-B irradiance on the ATP content of microorganisms of the Weddell Sea (Antartica)

Energy Technology Data Exchange (ETDEWEB)

Vosjan, J.H.; Nieuwland, G. (Netherlands Inst. for Sea Research, Den Burg (Netherlands)); Doehler, G. (Frankfurt Universitaet (Federal Republic of Germany). Botanisches Institut)

1990-06-01

The effect of UV-B irradiation on the ATP content of natural assemblages of planktonic microorganisms in the upper 30-m water layer of the Weddell Sea (Antartica) was studied. After five hours of irradiation with UV (290-320 nm) of 1.35 W.m{sup -2} a 75% decrease in the ATP content of the microorganisms was observed. (author). 11 refs.; 3 figs.

Stratification and the distribution of phytoplankton, nutrients, inorganic carbon, and sulfur in the surface waters of Weddell Sea leads

NARCIS (Netherlands)

Zemmelink, H. J.; Houghton, L.; Dacey, J. W. H.; Stefels, J.; Koch, B. P.; Wisotzki, A.; Scheltz, A.; Thomas, D. N.; Papadimitriou, S.; Kennedy, H.; Kuosa, H.; Dittmar, T.

2008-01-01

The distribution (fine resolution depth profiles) of major nutrients, chlorophyll-a, organic compounds, and phytoplankton (biomass and numbers) was examined in lead water in pack ice of the Weddell Sea. Samples were taken by pulling water into a syringe from a series of depths from 0.002 to 4m.

Decline of deep and bottom water ventilation and slowing down of anthropogenic carbon storage in the Weddell Sea, 1984-2011

NARCIS (Netherlands)

Huhn, Oliver; Rhein, Monika; Hoppema, Mario; van Heuven, Steven

We use a 27 year long time series of repeated transient tracer observations to investigate the evolution of the ventilation time scales and the related content of anthropogenic carbon (C-ant) in deep and bottom water in the Weddell Sea. This time series consists of chlorofluorocarbon (CFC)

Low post-glacial rebound rates in the Weddell Sea due to Late Holocene ice-sheet readvance.

OpenAIRE

Bradley, S.L.; Hindmarsh, R.C.A.; Whitehouse, P.L.; Bentley, M.J.; King, M.A.

2015-01-01

Many ice-sheet reconstructions assume monotonic Holocene retreat for the West Antarctic Ice Sheet, but an increasing number of glaciological observations infer that some portions of the ice sheet may be readvancing, following retreat behind the present-day margin. A readvance in the Weddell Sea region can reconcile two outstanding problems: (i) the present-day widespread occurrence of seemingly stable ice streams grounded on beds that deepen inland; and (ii) the inability of models of glacial...

Seabed images from Southern Ocean shelf regions off the northern Antarctic Peninsula and in the southeastern Weddell Sea

Science.gov (United States)

Piepenburg, Dieter; Buschmann, Alexander; Driemel, Amelie; Grobe, Hannes; Gutt, Julian; Schumacher, Stefanie; Segelken-Voigt, Alexandra; Sieger, Rainer

2017-07-01

Recent advances in underwater imaging technology allow for the gathering of invaluable scientific information on seafloor ecosystems, such as direct in situ views of seabed habitats and quantitative data on the composition, diversity, abundance, and distribution of epibenthic fauna. The imaging approach has been extensively used within the research project DynAMo (Dynamics of Antarctic Marine Shelf Ecosystems) at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research Bremerhaven (AWI), which aimed to comparatively assess the pace and quality of the dynamics of Southern Ocean benthos. Within this framework, epibenthic spatial distribution patterns have been comparatively investigated in two regions in the Atlantic sector of the Southern Ocean: the shelf areas off the northern tip of the Antarctic Peninsula, representing a region with above-average warming of surface waters and sea-ice reduction, and the shelves of the eastern Weddell Sea as an example of a stable high-Antarctic marine environment that is not (yet) affected by climate change. The AWI Ocean Floor Observation System (OFOS) was used to collect seabed imagery during two cruises of the German research vessel Polarstern, ANT-XXIX/3 (PS81) to the Antarctic Peninsula from January to March 2013 and ANT-XXXI/2 (PS96) to the Weddell Sea from December 2015 to February 2016. Here, we report on the image and data collections gathered during these cruises. During PS81, OFOS was successfully deployed at a total of 31 stations at water depths between 29 and 784 m. At most stations, series of 500 to 530 pictures ( > 15 000 in total, each depicting a seabed area of approximately 3.45 m2 or 2.3 × 1.5 m) were taken along transects approximately 3.7 km in length. During PS96, OFOS was used at a total of 13 stations at water depths between 200 and 754 m, yielding series of 110 to 293 photos (2670 in total) along transects 0.9 to 2.6 km in length. All seabed images taken during the two cruises

Active and Passive Microwave Determination of the Circulation and Characteristics of Weddell and Ross Sea Ice

Science.gov (United States)

Drinkwater, Mark R.; Liu, Xiang

2000-01-01

A combination of satellite microwave data sets are used in conjunction with ECMWF (Medium Range Weather Forecasts) and NCEP (National Center for Environment Prediction) meteorological analysis fields to investigate seasonal variability in the circulation and sea-ice dynamics of the Weddell and Ross Seas. Results of sea-ice tracking using SSM/I (Special Sensor Microwave Imager), Scatterometer and SAR images are combined with in-situ data derived from Argos buoys and GPS drifters to validate observed drift patterns. Seasonal 3-month climatologies of ice motion and drift speed variance illustrate the response of the sea-ice system to seasonal forcing. A melt-detection algorithm is used to track the onset of seasonal melt, and to determine the extent and duration of atmospherically-led surface melting during austral summer. Results show that wind-driven drift regulates the seasonal distribution and characteristics of sea-ice and the intensity of the cyclonic Gyre circulation in these two regions.

The contribution of the Weddell Gyre to the lower limb of the Global Overturning Circulation

OpenAIRE

Jullion, Loïc; Naveira Garabato, Alberto C.; Bacon, Sheldon; Meredith, Michael P.; Brown, Pete J.; Torres-Valdés, Sinhue; Speer, Kevin G.; Holland, Paul R.; Dong, Jun; Bakker, Dorothée; Hoppema, Mario; Loose, Brice; Venables, Hugh J.; Jenkins, William J.; Messias, Marie-José

2014-01-01

International audience; The horizontal and vertical circulation of the Weddell Gyre is diagnosed using a box inverse model constructed with recent hydrographic sections and including mobile sea ice and eddy transports. The gyre is found to convey 42 6 8 Sv (1 Sv 5 106 m3 s–1) across the central Weddell Sea and to intensify to 54 6 15 Sv further offshore. This circulation injects 36 6 13 TW of heat from the Antarctic Circumpolar Current to the gyre, and exports 51 6 23 mSv of freshwater, inclu...

Elephant overflows: Multi-annual variability in Weddell Sea Deep Water driven by surface forcing

Science.gov (United States)

Meijers, Andrew; Meredith, Michael; Abrahamsen, Povl; Naviera-Garabato, Alberto; Ángel Morales Maqueda, Miguel; Polzin, Kurt

2015-04-01

The volume of the deepest and densest water mass in Drake Passage, Lower Weddell Sea Deep Water (LWSDW), is shown to have been decreasing over the last 20 years of observations, with an associated reduction in density driven by freshening. Superimposed on this long term trend is a multi-annual oscillation with a period of 3-5 years. This variability only appears in Drake Passage; observations in the east of the Scotia Sea show a similar long term trend, but with no apparent multi-annual variability. Clues as to the source of this variability may be found on the continental slope at approximately 1000 m immediately north of Elephant Island on the northern tip of the Antarctic Peninsula. Here there is an intermittent westward flowing cold/fresh slope current whose volume and properties are strongly correlated with the LWSDW multi-annual variability, although leading the LWSDW by around one year. As the slope current and LWSDW are separated from each other both geographically and in water mass characteristics, their co-variability implies that they are responding to a common forcing, while the lag between deep LWSDW and shallow slope current provides information on the timescale of this response. A newly available high resolution temperature and salinity multi-year time series from the Elephant Island slope at 1000 m is compared with reanalysis and model derived surface fluxes, sea ice extent and wind stress. We find that there are strong positive relationships between the surface wind stress and heat flux over the shelf at the tip of the Antarctic Peninsula and the properties of the slope current at 1000 m on seasonal to annual timescales. We use tracer release experiments in the Southern Ocean State Estimate (SOSE) model to investigate the lag between the slope current and LWSDW timeseries and hypothesise that the observed multi-annual variability in both water masses is driven by surface forcing over the shelf and the overflow of modified water from the slope in

Oceanographic and topographic conditions structure benthic meiofauna communities in the Weddell Sea, Bransfield Strait and Drake Passage (Antarctic)

Science.gov (United States)

Veit-Köhler, Gritta; Durst, Stephan; Schuckenbrock, Jan; Hauquier, Freija; Durán Suja, Laura; Dorschel, Boris; Vanreusel, Ann; Martínez Arbizu, Pedro

2018-03-01

The marine environment of the tip of the Antarctic Peninsula is characterised by three oceanographically distinct regions for which we linked continental-slope meiofaunal patterns and environmental drivers on a large scale (100-300 km among ecoregions). Samples for meiofauna communities and sediment analyses were collected with a multicorer, water-column data were derived from water samples and CTD recordings. Meiofauna communities including individuals from 19 higher taxa were compared to a set of 16 environmental variables. We detected significant differences between the communities of Weddell Sea and those of Bransfield Strait and Drake Passage. The amount of phytopigments in the sediment, their freshness and the silt and clay content were driving factors for this separation. The highest meiofauna abundances were found at slopes in the Weddell Sea. Food banks may facilitate high standing stocks. There, the highest ever recorded copepod percentages for the Antarctic were related to the highest phytopigment contents while nematodes were extremely abundant even in deeper sediment layers at stations with fresh organic material. For Bransfield Strait and Drake Passage a sampling scheme of slopes and adjacent troughs was applied. The two regions were divided into three geographical "areas" with the two "habitat" types investigated for each area. Multivariate non-parametric permutational analysis of variance (PERMANOVA) showed that in Bransfield Strait slope and trough meiofauna communities differed significantly in all geographical areas while in Drake Passage this was only the case in the East. These differences were explained best by the regionally and topographically distinct characteristics of 7 out of 11 water-column and sediment-bound factors related to sediment grain size, food quantity and quality, water temperature and salinity. Environmental drivers of the benthic habitat are dependent on large-scale oceanographic conditions and are thus sensitive to changes

Tidal influences on a future evolution of the Filchner-Ronne Ice Shelf cavity in the Weddell Sea, Antarctica

Science.gov (United States)

Mueller, Rachael D.; Hattermann, Tore; Howard, Susan L.; Padman, Laurie

2018-02-01

Recent modeling studies of ocean circulation in the southern Weddell Sea, Antarctica, project an increase over this century of ocean heat into the cavity beneath Filchner-Ronne Ice Shelf (FRIS). This increase in ocean heat would lead to more basal melting and a modification of the FRIS ice draft. The corresponding change in cavity shape will affect advective pathways and the spatial distribution of tidal currents, which play important roles in basal melting under FRIS. These feedbacks between heat flux, basal melting, and tides will affect the evolution of FRIS under the influence of a changing climate. We explore these feedbacks with a three-dimensional ocean model of the southern Weddell Sea that is forced by thermodynamic exchange beneath the ice shelf and tides along the open boundaries. Our results show regionally dependent feedbacks that, in some areas, substantially modify the melt rates near the grounding lines of buttressed ice streams that flow into FRIS. These feedbacks are introduced by variations in meltwater production as well as the circulation of this meltwater within the FRIS cavity; they are influenced locally by sensitivity of tidal currents to water column thickness (wct) and non-locally by changes in circulation pathways that transport an integrated history of mixing and meltwater entrainment along flow paths. Our results highlight the importance of including explicit tidal forcing in models of future mass loss from FRIS and from the adjacent grounded ice sheet as individual ice-stream grounding zones experience different responses to warming of the ocean inflow.

Polonium-210 and lead-210 in the Southern Polar Ocean: Naturally occurring tracers of biological and hydrographical processes in the surface waters of the Antarctic Circumpolar Current and the Weddell Sea

International Nuclear Information System (INIS)

Friedrich, J.

1997-01-01

In this thesis the distribution of 210 Po and 210 Pb in the upper 600 m of the Antarctic Circumpolar Current and the Weddell Sea was investigated along north-south transects in austral spring and autumn. 210 Po and 210 Pb can serve as sensitive tracers for the special hydrographic conditions of the Antarctic Circumpolar Current and the Weddell Sea as well as for biological processes during phytoplankton blooms. The 210 Po/ 210 Pb disequilibrium was used as a tracer for particle export. This tracer integrates export on a timescale of 276 days because of the 138 day half-life of 210 Po and complements the 234 Th/ 238 U disequilibrium as another tracer for plankton production and export on a shorter timescale of several weeks. (orig.) [de

Biogeochemical Impact of Snow Cover and Cyclonic Intrusions on the Winter Weddell Sea Ice Pack

Science.gov (United States)

Tison, J.-L.; Schwegmann, S.; Dieckmann, G.; Rintala, J.-M.; Meyer, H.; Moreau, S.; Vancoppenolle, M.; Nomura, D.; Engberg, S.; Blomster, L. J.; Hendrickx, S.; Uhlig, C.; Luhtanen, A.-M.; de Jong, J.; Janssens, J.; Carnat, G.; Zhou, J.; Delille, B.

2017-12-01

Sea ice is a dynamic biogeochemical reactor and a double interface actively interacting with both the atmosphere and the ocean. However, proper understanding of its annual impact on exchanges, and therefore potentially on the climate, notably suffer from the paucity of autumnal and winter data sets. Here we present the results of physical and biogeochemical investigations on winter Antarctic pack ice in the Weddell Sea (R. V. Polarstern AWECS cruise, June-August 2013) which are compared with those from two similar studies conducted in the area in 1986 and 1992. The winter 2013 was characterized by a warm sea ice cover due to the combined effects of deep snow and frequent warm cyclones events penetrating southward from the open Southern Ocean. These conditions were favorable to high ice permeability and cyclic events of brine movements within the sea ice cover (brine tubes), favoring relatively high chlorophyll-a (Chl-a) concentrations. We discuss the timing of this algal activity showing that arguments can be presented in favor of continued activity during the winter due to the specific physical conditions. Large-scale sea ice model simulations also suggest a context of increasingly deep snow, warm ice, and large brine fractions across the three observational years, despite the fact that the model is forced with a snowfall climatology. This lends support to the claim that more severe Antarctic sea ice conditions, characterized by a longer ice season, thicker, and more concentrated ice are sufficient to increase the snow depth and, somehow counterintuitively, to warm the ice.

Turbidity, SOLAR RADIATION - ATMOSPHERIC and other data from NATHANIEL B. PALMER, ICE ISLANDS and AKADEMIK FYODOROV in the Weddell Sea from 1992-02-02 to 1992-06-18 (NODC Accession 9500052)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD) and Rosette Bottle sampling was done from helicopter, ship, and ice island. The data were collected in Weddell Sea as...

Coastal polynyas in the southern Weddell Sea: Variability of the surface energy budget

Science.gov (United States)

Renfrew, Ian A.; King, John C.; Markus, Thorsten

2002-06-01

The surface energy budget of coastal polynyas in the southern Weddell Sea has been evaluated for the period 1992-1998 using a combination of satellite observations, meteorological data, and simple physical models. The study focuses on polynyas that habitually form off the Ronne Ice Shelf. The coastal polynya areal data are derived from an advanced multichannel polynya detection algorithm applied to passive microwave brightness temperatures. The surface sensible and latent heat fluxes are calculated via a fetch-dependent model of the convective-thermal internal boundary layer. The radiative fluxes are calculated using well-established empirical formulae and an innovative cloud model. Standard meteorological variables that are required for the flux calculations are taken from automatic weather stations and from the National Centers for Environmental Production/National Center for Atmospheric Research reanalyses. The 7 year surface energy budget shows an overall oceanic warming due to the presence of coastal polynyas. For most of the period the summertime oceanic warming, due to the absorption of shortwave radiation, is approximately in balance with the wintertime oceanic cooling. However, the anomalously large summertime polynya of 1997-1998 allowed a large oceanic warming of the region. Wintertime freezing seasons are characterized by episodes of high heat fluxes interspersed with more quiescent periods and controlled by coastal polynya dynamics. The high heat fluxes are primarily due to the sensible heat flux component, with smaller complementary latent and radiative flux components. The average freezing season area-integrated energy exchange is 3.48 × 1019 J, with contributions of 63, 22, and 15% from the sensible, latent, and radiative components, respectively. The average melting season area-integrated energy exchange is -5.31 × 1019 J, almost entirely due to the radiative component. There is considerable interannual variability in the surface energy budget

Carnivorous sponges (Cladorhizidae) of the deep Weddell Sea, with descriptions of two new species

Science.gov (United States)

Dressler-Allame, Melina; Göcke, Christian; Kersken, Daniel; Plotkin, Alexander; Janussen, Dorte

2017-03-01

This paper presents 29 sponges of the family Cladorhizidae Dendy, 1922 sampled at 18 different stations in the Weddell Sea, Antarctic during two expeditions of RV Polarstern, PS61 ANT-XIX/2 ANDEEP 2 in 2002 and PS67 ANT-XXII/3 ANDEEP 3 in 2005. Fourteen species from four genera have been registered - one species of Asbestopluma Topsent, 1901, five species of Chondrocladia Thomson, 1873, three species of Cladorhiza Sars, 1872 and five species of Lycopodina Lundbeck, 1905. Six species are endemics of the Southern Ocean. Four species were previously only known from the areas north of the Antarctic and our records of them are thereby new for this region. Two species of Lycopodina, Lycopodina rhabdostylophora sp. nov. and Lycopodina pediculifera sp. nov., are new to science. Our study has considerably expanded the data on diversity of Cladorhizidae in the Southern Ocean. About 27 cladorhizid species (18-19% of global cladorhizid diversity) are now recorded for this region, of which 56% are endemics.

The gastropod-symbiotic sea anemone genus Isosicyonis Carlgren, 1927 (Actiniaria: Actiniidae: a new species from the Weddell Sea (Antarctica that clarifies the taxonomic position of the genus

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Estefanía Rodríguez

2008-03-01

Full Text Available A second species of the sea anemone genus Isosicyonis is described and illustrated from 16 specimens collected in the Weddell Sea (Antarctica on the Polarstern cruises ANT XVII/3, ANT XXI/2 and ANT XXIII/8. Isosicyonis striata n. sp. is easily distinguishable externally from the other species of the genus Isosicyonis alba by its pattern: white longitudinal stripes on the column, oral disc, and tentacles. It is also distinguished by internal features including the retractor muscles, parietobasilar muscles, marginal sphincter muscles, number of mesenteries, and cnidae. The genus Isosycionis is currently only known from the Southern Ocean. Both species of Isosicyonis live in association with a gastropod, with a single sea anemone occupying almost the whole shell of its gastropod host. The description of this new species, and our re-examination of Isosicyonis alba, resolves the controversial higher taxonomic position of the genus, confirming its placement within the Endomyaria.

Influence of tropical atmospheric variability on Weddell Sea deep water convection

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Kleppin, H.

2016-02-01

Climate reconstructions from ice core records in Greenland and Antarctica have revealed a series of abrupt climate transitions, showing a distinct relationship between northern and southern hemisphere climate during the last glacial period. The recent ice core records from West Antarctica (WAIS) point towards an atmospheric teleconnection as a possible trigger for the interhemispheric climate variability (Markle et al., 2015). An unforced simulation of the Community Climate System Model, version 4 (CCSM4) reveals Greenland warming and cooling events, caused by stochastic atmospheric forcing, that resemble Dansgaard-Oeschger cycles in pattern and magnitude (Kleppin et al., 2015). Anti-phased temperature changes in the Southern Hemisphere are small in magnitude and have a spatially varying pattern. We argue that both north and south high latitude climate variability is triggered by changes in tropical atmospheric deep convection in the western tropical Pacific. The atmospheric wave guide provides a fast communication pathway connecting the deep tropics and the polar regions. In the Southern Hemisphere this is manifested as a distinct pressure pattern over West Antarctica. These altered atmospheric surface conditions over the convective region can lead to destabilization of the water column and thus to convective overturning in the Weddell Sea. However, opposed to what is seen in the Northern Hemisphere no centennial scale variability can establish, due to the absence of a strong feedback mechanism between ocean, atmosphere and sea ice. Kleppin, H., Jochum, M., Otto-Bliesner, B., Shields, C. A., & Yeager, S. (2015). Stochastic Atmospheric Forcing as a Cause of Greenland Climate Transitions. Journal of Climate, (2015). Markle, B. and Coauthors (2015, April). Atmospheric teleconnections between the tropics and high southern latitudes during millennial climate change. In EGU General Assembly Conference Abstracts (Vol. 17, p. 2569).

Uplift rates from a new high-density GPS network in Palmer Land indicate significant late Holocene ice loss in the southwestern Weddell Sea

Science.gov (United States)

Wolstencroft, Martin; King, Matt A.; Whitehouse, Pippa L.; Bentley, Michael J.; Nield, Grace A.; King, Edward C.; McMillan, Malcolm; Shepherd, Andrew; Barletta, Valentina; Bordoni, Andrea; Riva, Riccardo E. M.; Didova, Olga; Gunter, Brian C.

2015-10-01

The measurement of ongoing ice-mass loss and associated melt water contribution to sea-level change from regions such as West Antarctica is dependent on a combination of remote sensing methods. A key method, the measurement of changes in Earth's gravity via the GRACE satellite mission, requires a potentially large correction to account for the isostatic response of the solid Earth to ice-load changes since the Last Glacial Maximum. In this study, we combine glacial isostatic adjustment modelling with a new GPS dataset of solid Earth deformation for the southern Antarctic Peninsula to test the current understanding of ice history in this region. A sufficiently complete history of past ice-load change is required for glacial isostatic adjustment models to accurately predict the spatial variation of ongoing solid Earth deformation, once the independently-constrained effects of present-day ice mass loss have been accounted for. Comparisons between the GPS data and glacial isostatic adjustment model predictions reveal a substantial misfit. The misfit is localized on the southwestern Weddell Sea, where current ice models under-predict uplift rates by approximately 2 mm yr-1. This under-prediction suggests that either the retreat of the ice sheet grounding line in this region occurred significantly later in the Holocene than currently assumed, or that the region previously hosted more ice than currently assumed. This finding demonstrates the need for further fieldwork to obtain direct constraints on the timing of Holocene grounding line retreat in the southwestern Weddell Sea and that GRACE estimates of ice sheet mass balance will be unreliable in this region until this is resolved.

Bacterial activity in sea ice and open water of the Weddell Sea, Antarctica: A microautoradiographic study.

Science.gov (United States)

Grossmann, S

1994-07-01

Metabolic activity of bacteria was investigated in open water, newly forming sea ice, and successive stages of pack ice in the Weddell Sea. Microautoradiography, using [(3)H]leucine as substrate, was compared with incorporation rates of [(3)H]leucine into proteins. Relation of [(3)H]leucine incorporation to the biomass of active bacteria provides information about changes of specific metabolic activity of cells. During a phytoplankton bloom in an ice-free, stratified water column, total numbers of bacteria in the euphotic zone averaged 2.3 × 10(5) ml(-1), but only about 13% showed activity via leucine uptake. Growth rate of the active bacteria was estimated as 0.3-0.4 days(-1). Total cell concentration of bacteria in 400 m depth was 6.6 × 10(4) ml(-1). Nearly 50% of these cells were active, although biomass production and specific growth rate were only about one-tenth that of the surface populations. When sea ice was forming in high concentrations of phytoplankton, bacterial biomass in the newly formed ice was 49.1 ng C ml(-1), exceeding that in open water by about one order of magnitude. Attachment of large bacteria to algal cells seems to cause their enrichment in the new ice, since specific bacterial activity was reduced during ice formation, and enrichment of bacteria was not observed when ice formed at low algal concentration. During growth of pack ice, biomass of bacteria increased within the brine channel system. Specific activity was still reduced at these later stages of ice development, and percentages of active cells were as low as 3-5%. In old, thick pack ice, bacterial activity was high and about 30% of cells were active. However, biomass-specific activity of bacteria remained significantly lower than that in open water. It is concluded that bacterial assemblages different to those of open water developed within the ice and were dominated by bacteria with lower average metabolic activity than those of ice-free water.

Modification of the deep salinity-maximum in the Southern Ocean by circulation in the Antarctic Circumpolar Current and the Weddell Gyre

Science.gov (United States)

Donnelly, Matthew; Leach, Harry; Strass, Volker

2017-07-01

The evolution of the deep salinity-maximum associated with the Lower Circumpolar Deep Water (LCDW) is assessed using a set of 37 hydrographic sections collected over a 20-year period in the Southern Ocean as part of the WOCE/CLIVAR programme. A circumpolar decrease in the value of the salinity-maximum is observed eastwards from the North Atlantic Deep Water (NADW) in the Atlantic sector of the Southern Ocean through the Indian and Pacific sectors to Drake Passage. Isopycnal mixing processes are limited by circumpolar fronts, and in the Atlantic sector, this acts to limit the direct poleward propagation of the salinity signal. Limited entrainment occurs into the Weddell Gyre, with LCDW entering primarily through the eddy-dominated eastern limb. A vertical mixing coefficient, κV of (2.86 ± 1.06) × 10-4 m2 s-1 and an isopycnal mixing coefficient, κI of (8.97 ± 1.67) × 102 m2 s-1 are calculated for the eastern Indian and Pacific sectors of the Antarctic Circumpolar Current (ACC). A κV of (2.39 ± 2.83) × 10-5 m2 s-1, an order of magnitude smaller, and a κI of (2.47 ± 0.63) × 102 m2 s-1, three times smaller, are calculated for the southern and eastern Weddell Gyre reflecting a more turbulent regime in the ACC and a less turbulent regime in the Weddell Gyre. In agreement with other studies, we conclude that the ACC acts as a barrier to direct meridional transport and mixing in the Atlantic sector evidenced by the eastward propagation of the deep salinity-maximum signal, insulating the Weddell Gyre from short-term changes in NADW characteristics.

Bacterial Standing Stock, Activity, and Carbon Production during Formation and Growth of Sea Ice in the Weddell Sea, Antarctica.

Science.gov (United States)

Grossmann, S; Dieckmann, G S

1994-08-01

Bacterial response to formation and growth of sea ice was investigated during autumn in the northeastern Weddell Sea. Changes in standing stock, activity, and carbon production of bacteria were determined in successive stages of ice development. During initial ice formation, concentrations of bacterial cells, in the order of 1 x 10 to 3 x 10 liter, were not enhanced within the ice matrix. This suggests that physical enrichment of bacteria by ice crystals is not effective. Due to low concentrations of phytoplankton in the water column during freezing, incorporation of bacteria into newly formed ice via attachment to algal cells or aggregates was not recorded in this study. As soon as the ice had formed, the general metabolic activity of bacterial populations was strongly suppressed. Furthermore, the ratio of [H]leucine incorporation into proteins to [H]thymidine incorporation into DNA changed during ice growth. In thick pack ice, bacterial activity recovered and growth rates up to 0.6 day indicated actively dividing populations. However, biomass-specific utilization of organic compounds remained lower than in open water. Bacterial concentrations of up to 2.8 x 10 cells liter along with considerably enlarged cell volumes accumulated within thick pack ice, suggesting reduced mortality rates of bacteria within the small brine pores. In the course of ice development, bacterial carbon production increased from about 0.01 to 0.4 mug of C liter h. In thick ice, bacterial secondary production exceeded primary production of microalgae.

A High-Resolution Model of Water Mass Transformation and Transport in the Weddell Sea

Science.gov (United States)

Hazel, J.; Stewart, A.

2016-12-01

The ocean circulation around the Antarctic margins has a pronounced impact on the global ocean and climate system. One of these impacts includes closing the global meridional overturning circulation (MOC) via formation of dense Antarctic Bottom Water (AABW), which ventilates a large fraction of the subsurface ocean. AABW is also partially composed of modified Circumpolar Deep Water (CDW), a warm, mid-depth water mass whose transport towards the continent has the potential to induce rapid retreat of marine-terminating glaciers. Previous studies suggest that these water mass exchanges may be strongly influenced by high-frequency processes such as downslope gravity currents, tidal flows, and mesoscale/submesoscale eddy transport. However, evaluating the relative contributions of these processes to near-Antarctic water mass transports is hindered by the region's relatively small scales of motion and the logistical difficulties in taking measurements beneath sea ice.In this study we develop a regional model of the Weddell Sea, the largest established source of AABW. The model is forced by an annually-repeating atmospheric state constructed from the Antarctic Mesoscale Prediction System data and by annually-repeating lateral boundary conditions constructed from the Southern Ocean State Estimate. The model incorporates the full Filchner-Ronne cavity and simulates the thermodynamics and dynamics of sea ice. To analyze the role of high-frequency processes in the transport and transformation of water masses, we compute the model's overturning circulation, water mass transformations, and ice sheet basal melt at model horizontal grid resolutions ranging from 1/2 degree to 1/24 degree. We temporally decompose the high-resolution (1/24 degree) model circulation into components due to mean, eddy and tidal flows and discuss the geographical dependence of these processes and their impact on water mass transformation and transport.

Trace element analysis in the serum and hair of Antarctic leopard seal, Hydrurga leptonyx, and Weddell seal, Leptonychotes weddellii

Energy Technology Data Exchange (ETDEWEB)

Gray, Rachael [Faculty of Veterinary Science, University of Sydney, NSW 2006 Australia (Australia); Australian Marine Mammal Research Centre PO Box 20 Mosman, NSW 2088 (Australia)], E-mail: rgray@vetsci.usyd.edu.au; Canfield, Paul [Faculty of Veterinary Science, University of Sydney, NSW 2006 (Australia); Rogers, Tracey [Australian Marine Mammal Research Centre PO Box 20 Mosman, NSW 2088 (Australia); Evolution and Ecology Research Centre and School of Biological Earth and Environmental Sciences, University of New South Wales, NSW 2052 (Australia)

2008-07-25

Leopard seal, Hydrurga leptonyx, and Weddell seal, Leptonychotes weddellii, occupy an upper trophic level within the Antarctic ecosystem and are useful indicator species in the Southern Ocean of trace element concentrations. Reference values for the concentration of 19 trace elements were determined in the serum and hair of leopard and Weddell seals sampled in Eastern Antarctica. These reference values can be used as 'baseline' levels for monitoring trace element concentrations in these species. Greater trace element concentrations were determined in hair compared to serum, indicating different time scales of trace element accumulation in these samples. For the majority of trace elements, except for Se in the leopard seal samples and Cr in the Weddell seal samples, significant regression relationships for trace element concentrations in hair and serum were not elucidated. Significant differences were determined in the concentrations of seven out of 15 elements with hair type, moult and new, in the leopard seal; concentrations in moult hair were determined to be greater than in new hair for all elements except Zn. Hair analysis was determined to be useful for monitoring exposure to trace elements and when collected off the ice from moulting seals, hair can be employed as a non-invasive sample for trace element analysis in leopard and Weddell seals.

Low post-glacial rebound rates in the Weddell Sea due to Late Holocene ice-sheet readvance

Science.gov (United States)

Bradley, Sarah L.; Hindmarsh, Richard C. A.; Whitehouse, Pippa L.; Bentley, Michael J.; King, Matt A.

2015-03-01

Many ice-sheet reconstructions assume monotonic Holocene retreat for the West Antarctic Ice Sheet, but an increasing number of glaciological observations infer that some portions of the ice sheet may be readvancing, following retreat behind the present-day margin. A readvance in the Weddell Sea region can reconcile two outstanding problems: (i) the present-day widespread occurrence of seemingly stable ice streams grounded on beds that deepen inland; and (ii) the inability of models of glacial isostatic adjustment to match present-day uplift rates. By combining a suite of ice loading histories that include a readvance with a model of glacial isostatic adjustment we report substantial improvements to predictions of present-day uplift rates, including reconciling one problematic observation of land sinking. We suggest retreat behind present grounding lines occurred when the bed was lower, and isostatic recovery has since led to shallowing, ice sheet re-grounding and readvance. The paradoxical existence of grounding lines in apparently unstable configurations on reverse bed slopes may be resolved by invoking the process of unstable advance, in accordance with our load modelling.

Modelling travel and residence times in the eastern Irish Sea

International Nuclear Information System (INIS)

Dabrowski, T.; Hartnett, M.

2008-01-01

The Irish Sea, which lies between 51 deg. N-56 deg. N and 2 deg. 50'W-7 deg. W, provides a sheltered environment to exploit valuable fisheries resource. Anthropogenic activity is a real threat to its water quality. The majority of freshwater input down rivers flows into the eastern Irish Sea. The structure of the water circulation was not well understood during the planning of Sellafield nuclear plant outfall site in the eastern Irish Sea. A three-dimensional primitive equation numerical model was applied to the Irish Sea to simulate both barotropic and baroclinic circulation within the region. High accuracy was achieved with regard to the prediction of both tidal circulation and surface and nearbed water temperatures across the region. The model properly represented the Western Irish Sea Gyre, induced by thermal stratification and not known during planning Sellafield. Passive tracer simulations based on the developed hydrodynamic model were used to deliver residence times of the eastern Irish Sea region for various times of the year as well as travel times from the Sellafield outfall site to various locations within the Irish Sea. The results indicate a strong seasonal variability of travel times from Sellafield to the examined locations. Travel time to the Clyde Sea is the shortest for the autumnal tracer release (90 days); it takes almost a year for the tracer to arrive at the same location if it is released in January. Travel times from Sellafield to Dublin Bay fall within the range of 180-360 days. The average residence time of the entire eastern Irish Sea is around 7 months. The areas surrounding the Isle of Man are initially flushed due to a predominant northward flow; a backwater is formed in Liverpool Bay. Thus, elevated tracer concentrations are predicted in Liverpool Bay in the case of accidental spills at the Sellafield outfall site

Zooplankton incidence in abnormally high sea surface temperature in the Eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Goswami, S.C.

Zooplankton in an abnormally high sea surface temperature (33.1 to 33.8 degrees C) and alternate bands of slick formation were studied in the Eastern Arabian Sea during 26 and 29 April 1981. The phenomenon which may be due to intense diurnal heating...

A new bed elevation model for the Weddell Sea sector of the West Antarctic Ice Sheet

Directory of Open Access Journals (Sweden)

H. Jeofry

2018-04-01

Full Text Available We present a new digital elevation model (DEM of the bed, with a 1 km gridding, of the Weddell Sea (WS sector of the West Antarctic Ice Sheet (WAIS. The DEM has a total area of ∼ 125 000 km2 covering the Institute, Möller and Foundation ice streams, as well as the Bungenstock ice rise. In comparison with the Bedmap2 product, our DEM includes new aerogeophysical datasets acquired by the Center for Remote Sensing of Ice Sheets (CReSIS through the NASA Operation IceBridge (OIB program in 2012, 2014 and 2016. We also improve bed elevation information from the single largest existing dataset in the region, collected by the British Antarctic Survey (BAS Polarimetric radar Airborne Science Instrument (PASIN in 2010–2011, from the relatively crude measurements determined in the field for quality control purposes used in Bedmap2. While the gross form of the new DEM is similar to Bedmap2, there are some notable differences. For example, the position and size of a deep subglacial trough (∼ 2 km below sea level between the ice-sheet interior and the grounding line of the Foundation Ice Stream have been redefined. From the revised DEM, we are able to better derive the expected routing of basal water and, by comparison with that calculated using Bedmap2, we are able to assess regions where hydraulic flow is sensitive to change. Given the potential vulnerability of this sector to ocean-induced melting at the grounding line, especially in light of the improved definition of the Foundation Ice Stream trough, our revised DEM will be of value to ice-sheet modelling in efforts to quantify future glaciological changes in the region and, from this, the potential impact on global sea level. The new 1 km bed elevation product of the WS sector can be found at https://doi.org/10.5281/zenodo.1035488.

A new bed elevation model for the Weddell Sea sector of the West Antarctic Ice Sheet

Science.gov (United States)

Jeofry, Hafeez; Ross, Neil; Corr, Hugh F. J.; Li, Jilu; Morlighem, Mathieu; Gogineni, Prasad; Siegert, Martin J.

2018-04-01

We present a new digital elevation model (DEM) of the bed, with a 1 km gridding, of the Weddell Sea (WS) sector of the West Antarctic Ice Sheet (WAIS). The DEM has a total area of ˜ 125 000 km2 covering the Institute, Möller and Foundation ice streams, as well as the Bungenstock ice rise. In comparison with the Bedmap2 product, our DEM includes new aerogeophysical datasets acquired by the Center for Remote Sensing of Ice Sheets (CReSIS) through the NASA Operation IceBridge (OIB) program in 2012, 2014 and 2016. We also improve bed elevation information from the single largest existing dataset in the region, collected by the British Antarctic Survey (BAS) Polarimetric radar Airborne Science Instrument (PASIN) in 2010-2011, from the relatively crude measurements determined in the field for quality control purposes used in Bedmap2. While the gross form of the new DEM is similar to Bedmap2, there are some notable differences. For example, the position and size of a deep subglacial trough (˜ 2 km below sea level) between the ice-sheet interior and the grounding line of the Foundation Ice Stream have been redefined. From the revised DEM, we are able to better derive the expected routing of basal water and, by comparison with that calculated using Bedmap2, we are able to assess regions where hydraulic flow is sensitive to change. Given the potential vulnerability of this sector to ocean-induced melting at the grounding line, especially in light of the improved definition of the Foundation Ice Stream trough, our revised DEM will be of value to ice-sheet modelling in efforts to quantify future glaciological changes in the region and, from this, the potential impact on global sea level. The new 1 km bed elevation product of the WS sector can be found at https://doi.org/10.5281/zenodo.1035488" target="_blank">https://doi.org/10.5281/zenodo.1035488.

Problems of the active tectonics of the Eastern Black Sea

Science.gov (United States)

Javakhishvili, Z.; Godoladze, T.; Dreger, D. S.; Mikava, D.; Tvaliashvili, A.

2016-12-01

The Black Sea Basin is the part of the Arabian Eurasian Collision zone and important unit for understanding the tectonic process of the region. This complex basin comprises two deep basins, separated by the mid-Black Sea Ridge. The basement of the Black Sea includes areas with oceanic and continental crust. It was formed as a "back-arc" basin over the subduction zone during the closing of the Tethys Ocean. In the past decades the Black Sea has been the subject of intense geological and geophysical studies. Several papers were published about the geological history, tectonics, basement relief and crustal and upper mantle structure of the basin. New tectonic schemes were suggested (e. g. Nikishin et al 2014, Shillington et al. 2008, Starostenko et al. 2004 etc.). Nevertheless, seismicity of the Black Sea is poorly studied due to the lack of seismic network in the coastal area. It is considered, that the eastern basin currently lies in a compressional setting associated with the uplift of the Caucasus and structural development of the Caucasus was closely related to the evolution of the Eastern Black Sea Basin. Analyses of recent sequence of earthquakes in 2012 can provide useful information to understand complex tectonic structure of the Eastern Black Sea region. Right after the earthquake of 2012/12/23, National Seismic monitoring center of Georgia deployed additional 4 stations in the coastal area of the country, close to the epicenter area, to monitor aftershock sequence. Seismic activity in the epicentral area is continuing until now. We have relocated approximately 1200 aftershocks to delineate fault scarf using data from Georgian, Turkish and Russian datacenters. Waveforms of the major events and the aftershocks were inverted for the fault plane solutions of the events. For the inversion were used green's functions, computed using new 1D velocity model of the region. Strike-slip mechanism of the major events of the earthquake sequence indicates extensional

The infauna of three widely distributed sponge species (Hexactinellida and Demospongiae) from the deep Ekström Shelf in the Weddell Sea, Antarctica

Science.gov (United States)

Kersken, Daniel; Göcke, Christian; Brandt, Angelika; Lejzerowicz, Franck; Schwabe, Enrico; Anna Seefeldt, Meike; Veit-Köhler, Gritta; Janussen, Dorte

2014-10-01

Due to their high abundance and large body size sponges have a central position in Antarctic zoobenthos, where they form the most extensive sponge grounds of the world. Though research on Antarctic benthos communities is quite established, research on sponge-associated infauna communities is scarce. We analyzed associated infauna of fifteen individuals of the sponge species Mycale (Oxymycale) acerata Kirkpatrick, 1907 (Demospongiae: Mycalina), Rossella antarctica Carter, 1872 and R. racovitzae Topsent, 1901 (both Hexactinellida: Lyssacinosida). Samples were collected from the deep Ekström Shelf at 602 m in the South-Eastern Weddell Sea, Antarctica, during the ANT XXIV-2 (SYSTCO I) expedition of RV Polarstern. The number of species, α- and β-diversity and the significantly different species composition of infauna communities related to sponge species were calculated, the latter via cluster analysis. The sponge-associated infauna consisted of five phyla: Foraminifera, Nematoda, Polychaeta, Mollusca and Arthropoda. In total 11,463 infaunal specimens were extracted and we found at least 76 associated species. Highest values of α-diversity were calculated for a sample of R. antarctica with a Shannon-Index of 1.84 and Simpson-Index of 0.72 respectively. Our results of the cluster-analysis show significant differences between infauna communities and a unique species composition for single sponge species. Polychaetes of the genus Syllis Lamarck, 1818 were numerous in M. acerata and genera like Pionosyllis Malmgren, 1867 and Cirratulus Lamarck, 1801 were numerous in R. antarctica. Individuals of the amphipod species Seba cf. dubia Schellenberg, 1926 were often found in R. antarctica and R. racovitzae while Colomastix fissilingua Schellenberg, 1926 was frequent in samples of M. acerata. Molluscs were present in M. acerata and R. antarctica but absent in R. racovitzae.

Submarine sand ridges and sand waves in the eastern part of the China Sea

Science.gov (United States)

Wu, Ziyin; Li, Shoujun; Shang, Jihong; Zhou, Jieqiong; Zhao, Dineng; Liang, Yuyang

2016-04-01

Integrated with multi-beam and single-beam echo sounding data, as well as historical bathymetric data, submarine bathymetric maps of the eastern part of the China Sea, including the Bohai Sea, Huanghai Sea, and East China Sea, are constructed to systematically study submarine sand ridges and sand waves in the eastern part of the China Sea, combined with high-resolution seismic, sub-bottom profile and borehole data. Submarine sand ridges are extraordinarily developed in the eastern part of the China Sea, and 7 sand ridge areas can be divided from north to south, that is, the Laotieshan Channel sand ridge area in the Bohai Sea, the Korea Bay sand ridge area in the southern Huanghai Sea, the sand ridge area in the eastern Huanghai islands and the Huanghai Troughs, the Jianggang sand ridge area in the western Huanghai Sea, the sand ridge area in the East China Sea shelf, and the sand ridge and sand wave area in the Taiwan Strait and Taiwan Banks. The distribution area of the sand ridges and sand waves covers more than 450,000 km2, wherein ~10,000 km2 in the Bohai Bay, ~200,000 km2 in the Huanghai Sea, ~200,000 km2 in the East China Sea shelf, and ~40,000 km2 in the Taiwan Strait and Taiwan Banks, respectively. The great mass of sand ridges are distributed within water depth of 5-160 m, with a total length of over 160 km and a main width of 5-10 km. The inner structure of the sand ridges presents features of high-angle inclined beddings, with main lithology of sands, sand-mud alternations partly visible, and a small number of mud cores. Dating results indicate that the sand ridges in the eastern part of the China Sea are mainly developed in the Holocene. Sea-level variation dominates the sand ridge evolution in the eastern part of the China Sea since the LGM, and the sand ridges developed in the area of < 60m water depth are appeared in bad activity, meanwhile sand ridges with good activity are still developed in large scale.

Corals, Canyons, and Conservation: Science Based Fisheries Management Decisions in the Eastern Bering Sea

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Steve A. MacLean

2017-05-01

Full Text Available When making science matter for conservation, marine conservation practitioners, and managers must be prepared to make the appropriate decision based on the results of the best available science used to inform it. For nearly a decade, many stakeholders encouraged the North Pacific Fishery Management Council to enact protections for deep-sea corals in several canyons in the Eastern Bering Sea slope. In 2014, at the request of the Council, the National Marine Fisheries Service, Alaska Fisheries Science Center conducted a strip-transect survey along the Eastern Bering Sea slope to validate the results of a model predicting the occurrence of deep-sea coral habitat. More than 250,000 photos were analyzed to estimate coral, sponge, and sea whip abundance, distribution, height, and vulnerability to anthropogenic damage. The results of the survey confirmed that coral habitat and occurrence was concentrated around Pribilof Canyon and the adjacent slope. The results also confirmed that the densities of corals in the Eastern Bering Sea were low, even where they occurred. After reviewing the best available scientific information, the Council concluded that there is no scientific evidence to suggest that deep-sea corals in the Eastern Bering Sea slope or canyons are at risk from commercial fisheries under the current management structure, and that special protections for deep-sea corals were not warranted.

The exclusive economic zone debates in the Eastern Mediterranean Sea and fisheries

OpenAIRE

Başeren, Bayram Öztürk and Sertaç Hami; Öztürk, Bayram

2015-01-01

Abstract Delimitation and proclamations of the Exclusive Economic Zone in the Eastern Mediterranean Sea is important issue for several reasons for the bordering nations. The Mediterranean Sea is unique case due to geographical characteristics and some conflicts already existed on maritime delimitations among some nations. It’s a matter of fact that; all States will have to reach agreement, regarding proclamations of the delimitation of the Exclusive Economic Zone in the Eastern Mediterranean ...

The exclusive economic zone debates in the Eastern Mediterranean Sea and fisheries

OpenAIRE

Başeren, Bayram Öztürk and Sertaç Hami

2008-01-01

Abstract Delimitation and proclamations of the Exclusive Economic Zone in the Eastern Mediterranean Sea is important issue for several reasons for the bordering nations. The Mediterranean Sea is unique case due to geographical characteristics and some conflicts already existed on maritime delimitations among some nations. It’s a matter of fact that; all States will have to reach agreement, regarding proclamations of the delimitation of the Exclusive Economic Zone in the Eastern Mediterranean ...

The physiological adaptations and toxin profiles of the toxic Alexandrium fundyense on the eastern Bering Sea and Chukchi Sea shelves.

Science.gov (United States)

Natsuike, Masafumi; Oikawa, Hiroshi; Matsuno, Kohei; Yamaguchi, Atsushi; Imai, Ichiro

2017-03-01

Abundant cyst distributions of the toxic dinoflagellate Alexandrium fundyense (previous A. tamarense north American clade) were recently observed on the north Chukchi Sea shelf and on the eastern Bering Sea shelf, suggesting that A. fundyense is both highly adapted to the local environments in the high latitude areas and might cause toxin contamination of plankton feeders. However, little is known about the physiological characteristics and toxin profiles of A. fundyense in these areas, which are characterized by low water temperatures, weak sunlight, and more or less permanent ice cover during winter. To clarify the physiological characteristics of A. fundyense, the effects of water temperature and light intensity on the vegetative growth and toxin profiles of this species were examined using A. fundyense strains isolated from one sediment sample collected from each area. Using the same sediments samples, seasonal changes of the cyst germination in different water temperatures were investigated. Vegetative cells grew at temperatures as low as 5°C and survived at 1°C under relatively low light intensity. They also grew at moderate water temperatures (10-15°C). Their cysts could germinate at low temperatures (1°C) and have an endogenous dormancy period from late summer to early spring, and warmer water temperatures (5-15°C) increased germination success. These physiological characteristics suggest that A. fundyense in the Chukchi Sea and eastern Bering Sea is adapted to the environments of high latitude areas. In addition, the results suggest that in the study areas A. fundyense has the potential to germinate and grow when water temperatures increase. Cellular toxin amounts of A. fundyense strains from the eastern Bering Sea and Chukchi Sea were ranged from 7.2 to 38.2 fmol cell -1 . These toxin amounts are comparable with A. fundyense strains isolated from other areas where PSP toxin contamination of bivalves occurs. The dominant toxin of the strains isolated

Identifying metabolic pathways for production of extracellular polymeric substances by the diatom Fragilariopsis cylindrus inhabiting sea ice.

Science.gov (United States)

Aslam, Shazia N; Strauss, Jan; Thomas, David N; Mock, Thomas; Underwood, Graham J C

2018-05-01

Diatoms are significant primary producers in sea ice, an ephemeral habitat with steep vertical gradients of temperature and salinity characterizing the ice matrix environment. To cope with the variable and challenging conditions, sea ice diatoms produce polysaccharide-rich extracellular polymeric substances (EPS) that play important roles in adhesion, cell protection, ligand binding and as organic carbon sources. Significant differences in EPS concentrations and chemical composition corresponding to temperature and salinity gradients were present in sea ice from the Weddell Sea and Eastern Antarctic regions of the Southern Ocean. To reconstruct the first metabolic pathway for EPS production in diatoms, we exposed Fragilariopsis cylindrus, a key bi-polar diatom species, to simulated sea ice formation. Transcriptome profiling under varying conditions of EPS production identified a significant number of genes and divergent alleles. Their complex differential expression patterns under simulated sea ice formation was aligned with physiological and biochemical properties of the cells, and with field measurements of sea ice EPS characteristics. Thus, the molecular complexity of the EPS pathway suggests metabolic plasticity in F. cylindrus is required to cope with the challenging conditions of the highly variable and extreme sea ice habitat.

77 FR 23209 - Endangered and Threatened Species; Proposed Delisting of Eastern DPS of Steller Sea Lions

Science.gov (United States)

2012-04-18

... of these fisheries are not likely to cause the eastern DPS to become in danger of extinction in the... coastal habitats is likely to cause the eastern DPS of Steller sea lion to become in danger of extinction... likely to cause the eastern DPS of Steller sea lions to become in danger of extinction in the foreseeable...

AFSC/ABL: Eastern Bering Sea (EMA-BASIS) Zooplankton data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O....

Buried paleo-sedimentary basins in the north-eastern Black Sea-Azov Sea area and tectonic implications (DOBRE-2)

Science.gov (United States)

Starostenko, Vitaly; Stephenson, Randell; Janik, Tomasz; Tolkunov, Anatoly

2014-05-01

A number of independent but inter-related projects carried out under the auspices of various national and international programmes in Ukraine including DARIUS were aimed at imaging the upper lithosphere, crustal and sedimentary basin architecture in the north-eastern Black Sea, southern Crimea and Kerch peninsulas and the Azov Sea. This region marks the transition from relatively undisturbed Precambrian European cratonic crust and lithosphere north of the Azov Sea to areas of significant Phanerozoic tectonics and basin development, in both extensional as well as compressional environments, to the south, including the eastern Black Sea rift, which is the main sedimentary basin of the study area. The wide-angle reflection and refraction (WARR) profile DOBRE-2, a Ukrainian national project with international participation (see below), overlapping some 115 km of the southern end of the DOBREfraction'99 profile (that crosses the intracratonic Donbas Foldbelt) in the north and running to the eastern Black Sea basin in the south, utilised on- and offshore recording and energy sources. It maps crustal velocity structure across the craton margin and documents, among other things, that the Moho deepens from 40 km to ~47 km to the southwest below the Azov Sea and Crimean-Caucasus deformed zone. A regional CDP seismic profile coincident with DOBRE-2, crossing the Azov Sea, Kerch Peninsula and the north-eastern Black Sea southwest to the Ukraine-Turkey border, acquired by Ukrgeofisika (the Ukrainian national geophysical company) reveals in its inferred structural relationships the ages of Cretaceous and younger extensional and subsequent basin inversion tectonic events as well as the 2D geometry of basement displacement associated with post mid-Eocene inversion. A direct comparison of the results of the WARR velocity model and the near-vertical reflection structural image has been made by converting the former into the time domain. The results dramatically demonstrate that

Transfer of seston lipids during a flagellate bloom from the surface to the benthic community in the Weddell Sea

Directory of Open Access Journals (Sweden)

Sergio Rossi

2013-09-01

Full Text Available Total lipid and fatty acid concentrations were studied in a late spring-early summer flagellate-dominated bloom in the Weddell Sea. These indicators were considered a good tool for assessing the quality of organic matter settling from surface to deep-water layers (epibenthic water layers. The results showed different patterns between the early (11-15 December 2003 and the late sampling period (18-27 December 2003 at all studied depths (5 m, 50 m and near-bottom water layers. Low phytoplankton biomass (mainly flagellates in the first half of the study corresponded to low total lipid and fatty acid concentrations. In the second sampling period a spring bloom (mainly flagellates and diatoms was detected, increasing the total lipid and fatty acid concentrations in the water column. The amount of settling organic matter from surface waters to the near-bottom water layers was high, especially in the late sampling period. Trophic markers showed evidence of a sink of available organic matter rich in quality and quantity, especially in terms of polyunsaturated fatty acids, for benthic organisms from surface layers to bottom layers in only a few days. The importance of studying short-time cycles in order to detect organic matter availability for benthic biota in view of the pulse-like dynamics of primary production in Antarctic waters is discussed.

Sea truth validation of sea WiFS ocean colour sensor in the coastal waters of the eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Desa, E.S.; Suresh, T.; Matondkar, S.G.P.; Desa, E.

In this paper we report bio-optical measurements made during an ocean colour validation cruise SK 149C in November 1999 of the research vessel Sagar Kanya in the coastal waters of the Eastern Arabian Sea. The chlorophyll concentration...

Constraining ice sheet history in the Weddell Sea, West Antarctica, using ice fabric at Korff Ice Rise

Science.gov (United States)

Brisbourne, A.; Smith, A.; Kendall, J. M.; Baird, A. F.; Martin, C.; Kingslake, J.

2017-12-01

The grounding history of ice rises (grounded area of independent flow regime within a floating ice shelf) can be used to constrain large scale ice sheet history: ice fabric, resulting from the preferred orientation of ice crystals due to the stress regime, can be used to infer this grounding history. With the aim of measuring the present day ice fabric at Korff Ice Rise, West Antarctica, a multi-azimuth wide-angle seismic experiment was undertaken. Three wide-angle common-midpoint gathers were acquired centred on the apex of the ice rise, at azimuths of 60 degrees to one another, to measure variation in seismic properties with offset and azimuth. Both vertical and horizontal receivers were used to record P and S arrivals including converted phases. Measurements of the variation with offset and azimuth of seismic traveltimes, seismic attenuation and shear wave splitting have been used to quantify seismic anisotropy in the ice column. The observations cannot be reproduced using an isotropic ice column model. Anisotropic ray tracing has been used to test likely models of ice fabric by comparison with the data. A model with a weak girdle fabric overlying a strong cluster fabric provides the best fit to the observations. Fabric of this nature is consistent with Korff Ice Rise having been stable for the order of 10,000 years without any ungrounding or significant change in the ice flow configuration across the ice rise for this period. This observation has significant implications for the ice sheet history of the Weddell Sea sector.

Growth Rate Potential of Juvenile Sockeye Salmon in Warmer and Cooler Years on the Eastern Bering Sea Shelf

Directory of Open Access Journals (Sweden)

Edward V. Farley

2009-01-01

Full Text Available A spatially explicit bioenergetics model was used to predict juvenile sockeye salmon Oncorhynchus nerka growth rate potential (GRP on the eastern Bering Sea shelf during years with cooler and warmer spring sea surface temperatures (SSTs. Annual averages of juvenile sockeye salmon GRP were generally lower among years with cooler SSTs and generally higher in offshore than nearshore regions of the eastern Bering Sea shelf during years with warmer SSTs. Juvenile sockeye salmon distribution was significantly (P<.05 related to GRP and their prey densities were positively related to spring SST (P<.05. Juvenile sockeye salmon GRP was more sensitive to changes in prey density and observed SSTs during years when spring SSTs were warmer (2002, 2003, and 2005. Our results suggest that the pelagic productivity on the eastern Bering Sea shelf was higher during years with warmer spring SSTs and highlight the importance of bottom-up control on the eastern Bering Sea ecosystem.

The role of feedbacks in Antarctic sea ice change

Science.gov (United States)

Feltham, D. L.; Frew, R. C.; Holland, P.

2017-12-01

The changes in Antarctic sea ice over the last thirty years have a strong seasonal dependence, and the way these changes grow in spring and decay in autumn suggests that feedbacks are strongly involved. The changes may ultimately be caused by atmospheric warming, the winds, snowfall changes, etc., but we cannot understand these forcings without first untangling the feedbacks. A highly simplified coupled sea ice -mixed layer model has been developed to investigate the importance of feedbacks on the evolution of sea ice in two contrasting regions in the Southern Ocean; the Amundsen Sea where sea ice extent has been decreasing, and the Weddell Sea where it has been expanding. The change in mixed layer depth in response to changes in the atmosphere to ocean energy flux is implicit in a strong negative feedback on ice cover changes in the Amundsen Sea, with atmospheric cooling leading to a deeper mixed layer resulting in greater entrainment of warm Circumpolar Deep Water, causing increased basal melting of sea ice. This strong negative feedback produces counter intuitive responses to changes in forcings in the Amundsen Sea. This feedback is absent in the Weddell due to the complete destratification and strong water column cooling that occurs each winter in simulations. The impact of other feedbacks, including the albedo feedback, changes in insulation due to ice thickness and changes in the freezing temperature of the mixed layer, were found to be of secondary importance compared to changes in the mixed layer depth.

Assessment of metal element concentrations in mussel (M. Galloprovincialis) in Eastern Black Sea, Turkey

Energy Technology Data Exchange (ETDEWEB)

Cevik, U. [Karadeniz Technical University, Department of Physics, 61080 Trabzon (Turkey)], E-mail: berrenazli@yahoo.com; Damla, N.; Kobya, A.I. [Karadeniz Technical University, Department of Physics, 61080 Trabzon (Turkey); Bulut, V.N. [Giresun University, Department of Chemistry, 28049 Giresun (Turkey); Duran, C. [Karadeniz Technical University, Department of Chemistry, 61080 Trabzon (Turkey); Dalgic, G. [Rize University, Faculty of Fisheries, 53100 Rize (Turkey); Bozaci, R. [Karadeniz Technical University, Department of Physics, 61080 Trabzon (Turkey)

2008-12-30

The main goal of this work is to determine the effects of pollution of copper, lead and zinc mines on the Eastern Black Sea. Metal and heavy metal concentrations in the Eastern Black Sea mussels were measured using Energy Dispersive X-ray Fluorescence (EDXRF) and Flame Atomic Absorption Spectroscopy (FAAS). The analytical results showed that the tissue of mussel in Eastern Black Sea contains K, Ca, Fe, Cu, Zn, and Sr elements, and the shell of mussel contains Ca, Cu, Sr, and Ba elements. Due to the detection limit of EDXRF, the mussels were analyzed with FAAS for Cr, Mn, Ni, Cd and Pb elements. An ANOVA and Pearson correlation analyses were performed. The results showed although that the mean concentrations of Cu and Zn for the tissue of the mussels were markedly above the permissible levels of the Turkish regulations, Zn concentration is in the limits of the Food and Agriculture Organization (FAO)

Studies on the microzooplankton from the central and eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Gauns, M; Mohanraju, R.; Madhupratap, M

Numerical abundance and composition of microzooplankton in the upper 200 m were studied from the central and eastern Arabian Sea during three seasons. Protozoans, comprising of ciliates (loricates and aloricates), flagellates and sarcodines were...

Dissolved aluminium in the surface microlayer of the eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Narvekar, P.V.; Singbal, S.Y.S.

Measurements of dissolved aluminium (Al) in surface microlayer (SML) samples from the eastern Arabian Sea during the southwest (summer) and northwast (winter) monsoon periods have revealed much higher concentrations (23-657 nmol kg sup(-1)) than...

AFSC/ABL: Eastern Bering Sea (BASIS) Coastal Research on Juvenile Salmon

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O....

Geothermal structure of the eastern Black Sea basin and the eastern Pontides orogenic belt: Implications for subduction polarity of Tethys oceanic lithosphere

Directory of Open Access Journals (Sweden)

Nafiz Maden

2013-07-01

Full Text Available The numerical results of thermal modeling studies indicate that the lithosphere is cold and strong beneath the Black Sea basin. The thermal lithospheric thickness increases southward from the eastern Pontides orogenic belt (49.4 km to Black Sea basin (152.2 km. The Moho temperature increases from 367 °C in the trench to 978 °C in the arc region. The heat flow values for the Moho surface change between 16.4 mW m−2 in the Black Sea basin and 56.9 mW m−2 in the eastern Pontides orogenic belt. Along the southern Black Sea coast, the trench region has a relatively low geothermal potential with respect to the arc and back-arc region. The numerical studies support the existence of southward subduction beneath the Pontides during the late Mesozoic–Cenozoic.

Advective pathways near the tip of the Antarctic Peninsula: Trends, variability and ecosystem implications

Science.gov (United States)

Renner, Angelika H. H.; Thorpe, Sally E.; Heywood, Karen J.; Murphy, Eugene J.; Watkins, Jon L.; Meredith, Michael P.

2012-05-01

Pathways and rates of ocean flow near the Antarctic Peninsula are strongly affected by frontal features, forcings from the atmosphere and the cryosphere. In the surface mixed layer, the currents advect material from the northwestern Weddell Sea on the eastern side of the Peninsula around the tip of the Peninsula to its western side and into the Scotia Sea, connecting populations of Antarctic krill (Euphausia superba) and supporting the ecosystem of the region. Modelling of subsurface drifters using a particle tracking algorithm forced by the velocity fields of a coupled sea ice-ocean model (ORCA025-LIM2) allows analysis of the seasonal and interannual variability of drifter pathways over 43 years. The results show robust and persistent connections from the Weddell Sea both to the west into the Bellingshausen Sea and across the Scotia Sea towards South Georgia, reproducing well the observations. The fate of the drifters is sensitive to their deployment location, in addition to other factors. From the shelf of the eastern Antarctic Peninsula, the majority enter the Bransfield Strait and subsequently the Bellingshausen Sea. When originating further offshore over the deeper Weddell Sea, drifters are more likely to cross the South Scotia Ridge and reach South Georgia. However, the wind field east and southeast of Elephant Island, close to the tip of the Peninsula, is crucial for the drifter trajectories and is highly influenced by the Southern Annular Mode (SAM). Increased advection and short travel times to South Georgia, and reduced advection to the western Antarctic Peninsula can be linked to strong westerlies, a signature of the positive phase of the SAM. The converse is true for the negative phase. Strong westerlies and shifts of ocean fronts near the tip of the Peninsula that are potentially associated with both the SAM and the El Niño-Southern Oscillation restrict the connection from the Weddell Sea to the west, and drifters then predominantly follow the open

Obsolete - AFSC/RACE/Eco-FOCI: 2010 Eastern Bering Sea Juvenile Survey

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Data collected on this cruise included the following: We conducted a juvenile fish and benthic fish prey survery in the eastern Bering Sea (61 3-meter beam trawls,...

Cenozoic structures and the tectonic evolution of the eastern North Sea

DEFF Research Database (Denmark)

Clausen, O.R.; Nielsen, S.B.; Egholm, D.L.

2011-01-01

Abundant seismic sections and well data from the Cenozoic succession in the eastern North Sea area generally reveal normal faulting, salt tectonics and localized tectonic inversion. However, inferences on the Cenozoic dynamic evolution of the region require thorough analysis of interactions between...... or cover tectonism took place. Our objectives are thus 1) to analyze the interaction between basement and cover structures, and if possible 2) to relate the structures to the regional tectonic evolution. The Zechstein evaporites pinch out onto the Ringkøbing-Fyn High, which in the eastern North Sea...... influencede.g. Miocene deposition and controlled the generation of second order faults. The latter detached along the top Chalk Group due to the topography generated during faulting, i.e. they are second order detachment surfaces. We conclude that the regional tectonic significance of the Cenozoic structures...

Tsunami Hazard Analysis for the Eastern Mediterranean and its Connected Seas

Science.gov (United States)

Necmioglu, Ocal; Meral Ozel, Nurcan

2015-04-01

Accurate earthquake source parameters are essential for any tsunami hazard assessment and mitigation, including early warning systems. Complex tectonic setting makes the a priori accurate assumptions of earthquake source parameters difficult and characterization of the faulting type is a challenge. Information on tsunamigenic sources is of crucial importance in the Eastern Mediterranean and its Connected Seas, especially considering the short arrival times and lack of offshore sea-level measurements. In addition, the scientific community have had to abandon the paradigm of a ''maximum earthquake'' predictable from simple tectonic parameters (Ruff and Kanamori, 1980) in the wake of the 2004 Sumatra event (Okal, 2010) and one of the lessons learnt from the 2011 Tohoku event was that tsunami hazard maps may need to be prepared for infrequent gigantic earthquakes as well as more frequent smaller-sized earthquakes (Satake, 2011). We have initiated an extensive modeling study to perform a deterministic Tsunami Hazard Analysis for the Eastern Mediterranean and its Connected Seas. Characteristic earthquake source parameters (strike, dip, rake, depth, Mwmax) at each 0.5° x 0.5° size bin for 0-40 km depth (total of 310 bins) and for 40-100 km depth (total of 92 bins) in the Eastern Mediterranean, Aegean and Black Sea region (30°N-48°N and 22°E-44°E) have been assigned from the harmonization of the available databases and previous studies. These parameters have been used as input parameters for the deterministic tsunami hazard modeling. Nested Tsunami simulations of 6h duration with a coarse (2 arc-min) grid resolution have been simulated at EC-JRC premises for Black Sea and Eastern and Central Mediterranean (30°N-41.5°N and 8°E-37°E) for each source defined using shallow water finite-difference SWAN code (Mader, 2004) for the magnitude range of 6.5 - Mwmax defined for that bin with a Mw increment of 0.1. Results show that not only the earthquakes resembling the

Variations in swells along Eastern Arabian Sea during the summer monsoon

Digital Repository Service at National Institute of Oceanography (India)

Johnson, G.; SanilKumar, V.; Sanjiv, P.C.; Singh, J.; Pednekar, P.S.; AshokKumar, K.; Dora, G.U.; Gowthaman, R.

A study was carried out to find the variation in wave characteristics along the eastern Arabian Sea and the influence of swells in the nearshore waves at 3 locations during summer monsoon in 2010. Percentage of swells in the measured waves was 75...

Atmosphere-surface interactions over polar oceans and heterogeneous surfaces

Energy Technology Data Exchange (ETDEWEB)

Vihma, T.

1995-12-31

Processes of interaction between the atmospheric boundary layer and the planetary surface have been studied with special emphasis on polar ocean surfaces: the open ocean, leads, polynyas and sea ice. The local exchange of momentum, heat and moisture has been studied experimentally both in the Weddell Sea and in the Greenland Sea. Exchange processes over heterogeneous surfaces are addressed by modelling studies. Over a homogeneous surface, the local turbulent fluxes can be reasonably well estimated using an iterative flux-profile scheme based on the Monin-Obukhov similarity theory. In the Greenland Sea, the near-surface air temperature and the generally small turbulent fluxes over the open ocean were affected by the sea surface temperature fronts. Over the sea ice cover in the Weddell Sea, the turbulent sensible heat flux was generally downwards, and together with an upward oceanic heat flux through the ice it compensated the heat loss from the surface via long-wave radiation. The wind dominated on time scales of days, while the current became important on longer time scales. The drift dynamics showed apparent spatial differences between the eastern and western regions, as well as between the Antarctic Circumpolar Current and the rest of the Weddell Sea. Inertial motion was present in regions of low ice concentration. The surface heterogeneity, arising e.g. from roughness or temperature distribution, poses a problem for the parameterization of surface exchange processes in large-scale models. In the case of neutral flow over a heterogeneous terrain, an effective roughness length can be used to parameterize the roughness effects

Atmosphere-surface interactions over polar oceans and heterogeneous surfaces

Energy Technology Data Exchange (ETDEWEB)

Vihma, T

1996-12-31

Processes of interaction between the atmospheric boundary layer and the planetary surface have been studied with special emphasis on polar ocean surfaces: the open ocean, leads, polynyas and sea ice. The local exchange of momentum, heat and moisture has been studied experimentally both in the Weddell Sea and in the Greenland Sea. Exchange processes over heterogeneous surfaces are addressed by modelling studies. Over a homogeneous surface, the local turbulent fluxes can be reasonably well estimated using an iterative flux-profile scheme based on the Monin-Obukhov similarity theory. In the Greenland Sea, the near-surface air temperature and the generally small turbulent fluxes over the open ocean were affected by the sea surface temperature fronts. Over the sea ice cover in the Weddell Sea, the turbulent sensible heat flux was generally downwards, and together with an upward oceanic heat flux through the ice it compensated the heat loss from the surface via long-wave radiation. The wind dominated on time scales of days, while the current became important on longer time scales. The drift dynamics showed apparent spatial differences between the eastern and western regions, as well as between the Antarctic Circumpolar Current and the rest of the Weddell Sea. Inertial motion was present in regions of low ice concentration. The surface heterogeneity, arising e.g. from roughness or temperature distribution, poses a problem for the parameterization of surface exchange processes in large-scale models. In the case of neutral flow over a heterogeneous terrain, an effective roughness length can be used to parameterize the roughness effects

Orbital-scale denitrification changes in the Eastern Arabian Sea during the last 800 kyrs.

Science.gov (United States)

Kim, Ji-Eun; Khim, Boo-Keun; Ikehara, Minoru; Lee, Jongmin

2018-05-04

Denitrification in the Arabian Sea is closely related to the monsoon-induced upwelling and subsequent phytoplankton production in the surface water. The δ 15 N values of bulk sediments collected at Site U1456 of the International Ocean Discovery Program (IODP) Expedition 355 reveal the orbital-scale denitrification history in response to the Indian Monsoon. Age reconstruction based on the correlation of planktonic foraminifera (Globigerinoides ruber) δ 18 O values with the LR04 stack together with the shipboard biostratigraphic and paleomagnetic data assigns the study interval to be 1.2 Ma. Comparison of δ 15 N values during the last 800 kyrs between Site U1456 (Eastern Arabian Sea) and Site 722B (Western Arabian Sea) showed that δ 15 N values were high during interglacial periods, indicating intensified denitrification, while the opposite was observed during glacial periods. Taking 6‰ as the empirical threshold of denitrification, the Eastern Arabian Sea has experienced a persistent oxygen minimum zone (OMZ) to maintain strong denitrification whereas the Western Arabian Sea has undergone OMZ breakdown during some glacial periods. The results of this study also suggests that five principal oceanographic conditions were changed in response to the Indian Monsoon following the interglacial and glacial cycles, which controls the degree of denitrification in the Arabian Sea.

Circumstantial Evidence of Possible Hot Spot Activity Outside Rhodes, Eastern Mediterranean Sea

OpenAIRE

Miliaresis, George

2014-01-01

Zouzias Dimitrios, St Seymour Karen, Miliaresis George, Vamvoukakis Costas (2008). Circumstantial Evidence of Possible Hot Spot Activity Outside Rhodes, Eastern Mediterranean Sea. 3rd International Conference on the Geology of the Tethys (8-11 January, 2008, South Valley University - Aswan). [Abstract in Program

Main Introduction Way of Indo-Pacific and Red Sea Originated Benthic Foraminifers to the Eastern Mediterranean

Directory of Open Access Journals (Sweden)

Engin MERİÇ

2015-12-01

Full Text Available Majority of the alien foraminifers recorded in the eastern Mediterranean are Indo-Pacific originated and entered the Mediterranean via Suez Canal. In this study, current literature on the alien benthic foraminiferal fauna of the eastern Mediterranean was reviewed and the main dispersal pathways are determined. Distribution patterns of the alien species suggests that most of the species are introduced via Suez Canal and expand their range of distributions in a counter-clockwise manner by the general surface currents of the eastern Mediterranean. However, not all, but some of the species have also been dispersed westwards along the North African coast and reached central Mediterranean. Locally abundant records of Euthymonacha polita (Chapman, Coscinospira acicularis (Batsch and Amphistegina lobifera in the Aegean Sea indicates that Suez Canal may not be the only vector for the Indo-Pacific species to enter eastern Mediterranean and submarine springs help these thermophilic species to form establish populations in cool waters of the northern Aegean and the Sea of Marmara

AFSC/ABL: Eastern Bering Sea (BASIS) Coastal Research on Juvenile Salmon (Oceanography data)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O....

AFSC/RACE/EcoFOCI: 2010 Eastern Bering Sea Juvenile Survey - 1MF10

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Data collected on this cruise included the following: We conducted a juvenile fish and benthic fish prey survery in the eastern Bering Sea (61 3-meter beam trawls,...

Data from investigation on seismic Sea waves events in the Eastern Mediterranean from 1000 to 1500 A.D.

Directory of Open Access Journals (Sweden)

J. ANTONOPOULOS

1980-06-01

Full Text Available Tsunamis from 1000 to 1500 A.D. in the Eastern Mediterranean
Sea between 31-44 N and 18-36 E excluding the Black Sea
and the Italian coasts of the Adriatic Sea is the object of the
present paper.

Data from investigation on seismic Sea waves events in the Eastern Mediterranean from 1900 to 1980 A.D.

Directory of Open Access Journals (Sweden)

J. ANTONOPOULOS

1980-06-01

Full Text Available Tsunamis from 1900 to 1980 A.D. in the Eastern Mediterranean
Sea between 31-44 N and 18-36 E excluding the Black Sea
and the Italian coasts of the Adriatic Sea is the object of the
present paper.

Evidence of increased toxic Alexandrium tamarense dinoflagellate blooms in the eastern Bering Sea in the summers of 2004 and 2005.

Directory of Open Access Journals (Sweden)

Masafumi Natsuike

Full Text Available The eastern Bering Sea has a vast continental shelf, which contains various endangered marine mammals and large fishery resources. Recently, high numbers of toxic A. tamarense resting cysts were found in the bottom sediment surface of the eastern Bering Sea shelf, suggesting that the blooms have recently occurred. However, little is known about the presence of A. tamarense vegetative cells in the eastern Bering Sea. This study's goals were to detect the occurrence of A. tamarense vegetative cells on the eastern Bering Sea shelf and to find a relationship between environmental factors and their presence. Inter-annual field surveys were conducted to detect A. tamarense cells and environmental factors, such as nutrients, salinity, chlorophyll a, and water temperature, along a transect line on the eastern Bering Sea shelf during the summers of 2004, 2005, 2006, 2009, 2012, and 2013. A. tamarense vegetative cells were detected during every sampling year, and their quantities varied greatly from year to year. The maximum cell densities of A. tamarense observed during the summers of 2004 and 2005 were much higher than the Paralytic shellfish poisoning warning levels, which are greater than 100-1,000 cells L-1, in other subarctic areas. Lower quantities of the species occurred during the summers of 2009, 2012, and 2013. A significant positive correlation between A. tamarense quantity and water temperature and significant negative correlations between A. tamarense quantity and nutrient concentrations (of phosphate, silicate, and nitrite and nitrate were detected in every sampling period. The surface- and bottom-water temperatures varied significantly from year to year, suggesting that water temperatures, which have been known to affect the cell growth and cyst germination of A. tamarense, might have affected the cells' quantities in the eastern Bering Sea each summer. Thus, an increase in the Bering Sea shelf's water temperature during the summer will

Evidence of increased toxic Alexandrium tamarense dinoflagellate blooms in the eastern Bering Sea in the summers of 2004 and 2005.

Science.gov (United States)

Natsuike, Masafumi; Saito, Rui; Fujiwara, Amane; Matsuno, Kohei; Yamaguchi, Atsushi; Shiga, Naonobu; Hirawake, Toru; Kikuchi, Takashi; Nishino, Shigeto; Imai, Ichiro

2017-01-01

The eastern Bering Sea has a vast continental shelf, which contains various endangered marine mammals and large fishery resources. Recently, high numbers of toxic A. tamarense resting cysts were found in the bottom sediment surface of the eastern Bering Sea shelf, suggesting that the blooms have recently occurred. However, little is known about the presence of A. tamarense vegetative cells in the eastern Bering Sea. This study's goals were to detect the occurrence of A. tamarense vegetative cells on the eastern Bering Sea shelf and to find a relationship between environmental factors and their presence. Inter-annual field surveys were conducted to detect A. tamarense cells and environmental factors, such as nutrients, salinity, chlorophyll a, and water temperature, along a transect line on the eastern Bering Sea shelf during the summers of 2004, 2005, 2006, 2009, 2012, and 2013. A. tamarense vegetative cells were detected during every sampling year, and their quantities varied greatly from year to year. The maximum cell densities of A. tamarense observed during the summers of 2004 and 2005 were much higher than the Paralytic shellfish poisoning warning levels, which are greater than 100-1,000 cells L-1, in other subarctic areas. Lower quantities of the species occurred during the summers of 2009, 2012, and 2013. A significant positive correlation between A. tamarense quantity and water temperature and significant negative correlations between A. tamarense quantity and nutrient concentrations (of phosphate, silicate, and nitrite and nitrate) were detected in every sampling period. The surface- and bottom-water temperatures varied significantly from year to year, suggesting that water temperatures, which have been known to affect the cell growth and cyst germination of A. tamarense, might have affected the cells' quantities in the eastern Bering Sea each summer. Thus, an increase in the Bering Sea shelf's water temperature during the summer will increase the

Nutrient biogeochemistry of the eastern Arabian Sea during the southwest monsoon retreat

Digital Repository Service at National Institute of Oceanography (India)

George, R; Muraleedharan, K.R; Martin, G.D.; Sabu, P.; Gerson, V.J.; Dineshkumar, P.K.; Nair, S.M.; Chandramohanakumar, N.; Nair, K.K.C.

and adjoining southeastern Arabian Sea. Curr Sci 96:364–375 Jyothibabu R, Madhu NV, Jayalakshmi KV, Balachandran KK, Shiyas CA, Martin GD, Nair KKC (2006) Impact of freshwater influx on microzooplankton mediated food web in a tropical estuary (Cochin backwaters... ARTICLE Nutrient biogeochemistry of the eastern Arabian Sea during the southwest monsoon retreat Rejomon George • K. R. Muraleedharan • G. D. Martin • P. Sabu • Vijay John Gerson • P. K. Dineshkumar • S. M. Nair • N. Chandramohanakumar • K. K. C. Nair...

Ecology and distribution of recent planktonic foraminifera in eastern part of Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Rao, K.K.; Jayalakshmy, K.V.; Kutty, M.K.

Thirty species of living planktonic foraminifera have been studied from 97 plankton tows collected from the eastern Arabian Sea with an accent on their ecological and distributional aspects. Species density is higher with less dominance in the deep...

Deterministic Tectonic Origin Tsunami Hazard Analysis for the Eastern Mediterranean and its Connected Seas

Science.gov (United States)

Necmioglu, O.; Meral Ozel, N.

2014-12-01

Accurate earthquake source parameters are essential for any tsunami hazard assessment and mitigation, including early warning systems. Complex tectonic setting makes the a priori accurate assumptions of earthquake source parameters difficult and characterization of the faulting type is a challenge. Information on tsunamigenic sources is of crucial importance in the Eastern Mediterranean and its Connected Seas, especially considering the short arrival times and lack of offshore sea-level measurements. In addition, the scientific community have had to abandon the paradigm of a ''maximum earthquake'' predictable from simple tectonic parameters (Ruff and Kanamori, 1980) in the wake of the 2004 Sumatra event (Okal, 2010) and one of the lessons learnt from the 2011 Tohoku event was that tsunami hazard maps may need to be prepared for infrequent gigantic earthquakes as well as more frequent smaller-sized earthquakes (Satake, 2011). We have initiated an extensive modeling study to perform a deterministic Tsunami Hazard Analysis for the Eastern Mediterranean and its Connected Seas. Characteristic earthquake source parameters (strike, dip, rake, depth, Mwmax) at each 0.5° x 0.5° size bin for 0-40 km depth (total of 310 bins) and for 40-100 km depth (total of 92 bins) in the Eastern Mediterranean, Aegean and Black Sea region (30°N-48°N and 22°E-44°E) have been assigned from the harmonization of the available databases and previous studies. These parameters have been used as input parameters for the deterministic tsunami hazard modeling. Nested Tsunami simulations of 6h duration with a coarse (2 arc-min) and medium (1 arc-min) grid resolution have been simulated at EC-JRC premises for Black Sea and Eastern and Central Mediterranean (30°N-41.5°N and 8°E-37°E) for each source defined using shallow water finite-difference SWAN code (Mader, 2004) for the magnitude range of 6.5 - Mwmax defined for that bin with a Mw increment of 0.1. Results show that not only the

Earthquake Scenario-Based Tsunami Wave Heights in the Eastern Mediterranean and Connected Seas

Science.gov (United States)

Necmioglu, Ocal; Özel, Nurcan Meral

2015-12-01

We identified a set of tsunami scenario input parameters in a 0.5° × 0.5° uniformly gridded area in the Eastern Mediterranean, Aegean (both for shallow- and intermediate-depth earthquakes) and Black Seas (only shallow earthquakes) and calculated tsunami scenarios using the SWAN-Joint Research Centre (SWAN-JRC) code ( Mader 2004; Annunziato 2007) with 2-arcmin resolution bathymetry data for the range of 6.5—Mwmax with an Mw increment of 0.1 at each grid in order to realize a comprehensive analysis of tsunami wave heights from earthquakes originating in the region. We defined characteristic earthquake source parameters from a compiled set of sources such as existing moment tensor catalogues and various reference studies, together with the Mwmax assigned in the literature, where possible. Results from 2,415 scenarios show that in the Eastern Mediterranean and its connected seas (Aegean and Black Sea), shallow earthquakes with Mw ≥ 6.5 may result in coastal wave heights of 0.5 m, whereas the same wave height would be expected only from intermediate-depth earthquakes with Mw ≥ 7.0 . The distribution of maximum wave heights calculated indicate that tsunami wave heights up to 1 m could be expected in the northern Aegean, whereas in the Black Sea, Cyprus, Levantine coasts, northern Libya, eastern Sicily, southern Italy, and western Greece, up to 3-m wave height could be possible. Crete, the southern Aegean, and the area between northeast Libya and Alexandria (Egypt) is prone to maximum tsunami wave heights of >3 m. Considering that calculations are performed at a minimum bathymetry depth of 20 m, these wave heights may, according to Green's Law, be amplified by a factor of 2 at the coastline. The study can provide a basis for detailed tsunami hazard studies in the region.

Controls on organic carbon distribution in sediments from the eastern Arabian Sea margin

Digital Repository Service at National Institute of Oceanography (India)

Thamban, M.; Rao, V.P.; Raju, S.V.

Sediment cores from the upper continental slope of the eastern Arabian Sea have high organic carbon (OC), CaCO sub(3), and sand content at the top. The values decrease with increasing depth in the Holocene and Upper Pleistocene. Topographic highs...

AFSC/ABL: Eastern Bering Sea (BASIS) Coastal Research on Juvenile Salmon (TSG-thermosalinigraph data)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O....

The relationship between volatile halocarbons and phytoplankton pigments during a Trichodesmium bloom in the coastal eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Roy, R.; Pratihary, A.; Narvenkar, G.; Mochemadkar, S.; Gauns, M.; Naqvi, S.W.A.

and 5 th April 2007 during regular visits to the Candolim Time Series (CaTS) station G3 located in the eastern Arabian Sea off Goa, India (Figure 1a). In order to investigate the phenomenon in detail and to extend the observations further offshore.... Chemosphere 45, 371-377. 14 Figure Captions Figure 1. a) Sampling locations in the eastern Arabian Sea off Goa; b) picture showing patchy Trichodesmium bloom observed at CaTS station G3. April. Figure 2. MODIS satellite observations from (showing...

137 Caesium distribution in the eastern Mediterranean Sea. Recent changes and future trends

International Nuclear Information System (INIS)

Papucci, C.; Delfanti, R.

1999-01-01

A series of sampling campaigns were carried out in the eastern Mediterranean in the period 1995-1997, to examine the relationship between the distribution of 137Cs in the water column and water mass circulation. 137Cs concentration in the surface water ranges between 3.3 and 4.0 mBq/l all over the area, indicating that the input due to the Chernobyl accident has been transferred to deep water layers by convection processes. In fact, in the vertical profiles, relative maxima are observed in the intermediate (4 mBq/l) and deep waters (∼2.5 mBq/l) formed after the Chernobyl accident. A clear Chernobyl signal also traces the new deep waters formed in the Aegean Sea that, exiting from the Cretan Arc Straits, since 1991 are spreading in the bottom layer of the eastern Mediterranean. The changes in 137Cs vertical profiles related to the new thermohaline circulation of the intermediate and deep waters of the eastern Mediterranean are being monitored at a deep station in the western Ionian Sea. The 1997 profile shows a decrease in 137Cs concentration both in the Levantine intermediate water and in the eastern Mediterranean deep water with respect to 1996. The decrease in Levantine intermediate water is likely due to seasonal/interannual variability, while the changes in the deep layer are related to the spreading westward into the Ionian of the new Aegean dense water. Along the path towards the western Mediterranean, 137Cs content in the Levantine intermediate water decreases from ∼4 mBq/l in the W-Ionian Sea to ∼2 mBq/l at the western sill of the Sicily Straits, due to mixing with underlying water, with lower caesium content, near the Malta Sill. Time-series measurements at the western sill of the Sicily Straits show that, while 137Cs concentration in the surface water entering the eastern Mediterranean remained constant (∼3.5 mBq/l) in the period 1993-1997, its level in the Levantine intermediate water leaving the basin decreased from 3.5 to 2.0 mBq/l

Census of biodiversity in marine caves of the eastern Mediterranean Sea

Directory of Open Access Journals (Sweden)

V. GEROVASILEIOU

2015-03-01

Full Text Available Scientific information on the biodiversity of marine caves in the eastern Mediterranean is limited, especially when considering the extensively studied caves of the north-western and central Mediterranean. Aiming to enhance current knowledge regarding cave communities, this study represents a first assessment of the marine cave biota of the eastern Mediterranean, as this has been defined by the European Union’s Marine Strategy Framework Directive (MSFD. Information retrieved from an extensive overview of relevant scientific documents was combined with original data recorded from 23 marine caves of the north-eastern Mediterranean. Our results report a total of 520 taxa recorded in eastern Mediterranean marine caves to date, the majority of which are sponges, polychaetes, rhodophytes, bivalves, fishes, and gastropods. These include several protected, endemic, and alien species. However, not all taxonomic groups have been equally studied among different areas and future studies are expected to raise the number of endemic and alien species. The overall observed trend is that the reported species number is generally related to sampling effort and scientific expertise. The most well-studied marine cave communities of the eastern Mediterranean are those of the Aegean Sea (especially its northern sector, which presented the highest number of species, followed by those of the Levantine. Furthermore, our research in Aegean caves revealed numerous new records for the marine cave fauna of the eastern basin, while several species are reported for the first time in the marine cave habitat. The critical need for further scientific research, monitoring, and conservation of this unique ecosystem was highlighted by (i the presence of certain species endemic to the eastern Mediterranean coupled with a high proportion of alien species, especially in the Levantine, and (ii the marine cave habitat availability in isolated insular areas of the eastern Mediterranean.

Bringing Antarctic Weddell seals to the classroom through PolarTREC

Science.gov (United States)

Eilers, A. A.

2017-12-01

PolarTREC (Teachers and Researchers Exploring and Collaborating) is an NSF funded professional development opportunity in which K-12 teachers and informal educators participated in hands-on field research experiences in the Polar Regions. The program goal is to invigorate polar science education and understanding by bringing together educators and polar researchers. This unique opportunity for educators has two main components: a 4-6 week field experience and a classroom/community connection piece. In preparation for these experiences, museum educator Alex Eilers and science team lead Dr. Jennifer Burns planned, developed and executed extensive outreach efforts for both students and the community to highlight the Weddell seal research project during the 2012, 2014 and 2016 seasons. The following outreach activities summarize the team's most successful attempts at engaging schoolchildren, teachers and the public, creating a broader impact of the Weddell seal scientific project. On-line Daily journal entries were uploaded to the PolarTREC website encouraging an active interaction between the science team and participants. A Polar Connect event offered participants a real-time, interactive internet presentation with the team. Schools A multitude of on-site presentations were made in classrooms, at teacher workshops and faculty meetings. Two 45 minute labs were developed for students visiting the museum, Animals of the Antarctic and Journey to the Poles, the latter is now included in our ongoing program repertoire. Two travelling kits, Extreme Cold Weather Gear and The Weddell Seal, were developed by museum staff and continue to circulate through schools. A multi-lesson educational module was developed by museum staff to bridge the gap between the scientific research conducted in the field and students in grades 3-8. It contains curriculum-based lessons, field data and strategic methods to assist students in analyzing the data. Community Community-wide interest

Assessment of legacy and emerging persistent organic pollutants in Weddell seal tissue (Leptonychotes weddellii) near McMurdo Sound, Antarctica

Energy Technology Data Exchange (ETDEWEB)

Trumble, Stephen J.; Robinson, Eleanor M. [Baylor University, One Bear Place 97388, Waco, TX 76798-7388 (United States); Noren, Shawn R. [Institute of Marine Science, University of California, Santa Cruz, CA (United States); Usenko, Sascha, E-mail: Sascha_Usenko@baylor.edu [Baylor University, One Bear Place 97388, Waco, TX 76798-7388 (United States); Davis, Jay [U.S. Fish and Wildlife Service, Western Washington Fish and Wildlife Office, Lacey, WA 98503 (United States); Kanatous, Shane B. [Department of Biology, Colorado State University, Fort Collins, CO 80523-1878 (United States)

2012-11-15

Muscle samples were collected from pup, juvenile and adult Weddell seals (Leptonychotes weddellii) near McMurdo Sound, Antarctica during the austral summer of 2006. Blubber samples were collected from juvenile and adult seals. Samples were analyzed for emerging and legacy persistent organic pollutants (POPs) including current and historic-use organochlorine pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). Of the 41 target analytes, 28 contaminants were recovered from the Weddell seal blubber, in this order of prevalence: p,p Prime -DDE, p,p Prime -DDT, trans-nonachlor, mirex, cis-nonachlor, PCB 153, PCB 138, dieldrin, heptachlor epoxide, nonachlor III, PCB 187, oxychlordane, cis-chlordane, PCB 118, PBDE 47, PCB 156, PCB 149, PCB 180, PCB 101, PCB 170, PCB 105, o,p Prime -DDT, PCB 99, trans-chlordane, PCB 157, PCB 167, PCB 189, and PCB 114. Fewer POPs were found in the muscle samples, but were similar in the order of prevalence to that of the blubber: p,p Prime -DDE, o,p Prime -DDT, trans-nonachlor, nonachlor III, oxychlordane, p,p Prime -DDT, dieldrin, mirex, cis-nonachlor, PCB 138, and PCB 105. Besides differences in toxicant concentrations reported between the muscle and blubber, we found differences in POP levels according to age class and suggest that differences in blubber storage and/or mobilization of lipids result in age class differences in POPs. To our knowledge, such ontogenetic associations are novel. Importantly, data from this study suggest that p,p Prime -DDT is becoming less prevalent temporally, resulting in an increased proportion of its metabolite p,p Prime -DDE in the tissues of this top predator. In addition, this study is among the first to identify a PBDE congener in Weddell seals near the McMurdo Station. This may provide evidence of increased PBDE transport and encroachment in Antarctic wildlife. -- Highlights: Black-Right-Pointing-Pointer PBDE measuring in Weddell seal blubber. Black

The presence of the Indo-Pacific symbiont-bearing foraminifer Amphistegina lobifera in Greek coastal ecosystems (Aegean Sea, Eastern Mediterranean

Directory of Open Access Journals (Sweden)

M.V. TRIANTAPHYLLOU

2009-12-01

Full Text Available During the last decades, hundreds of species of Indo-Pacific origin from the Red Sea have traversed the Suez Canal and settled in the Eastern Mediterranean. Nowadays, Amphistegina lobifera Larsen, is known to be a successful immigrant that is widely distributed in the coastal ecosystems of the Eastern Mediterranean Sea. Amphistegina is the most common epiphytic, symbiont- bearing large foraminifer. In this study we provide additional data on the presence of this species in the coastal ecosystems of Aegean Sea, Greece. The high relative abundance of A. lobifera is the result of very successful adaptation of this species to local conditions and suggests that it has become a significant part of the epiphytic foraminiferal fauna.

Swath bathymetric investigation of the seamounts located in the Laxmi Basin, eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Bhattacharya, G.C.; Murty, G.P.S.; Srinivas, K.; Chaubey, A.K.; Sudhakar, T.; Nair, R.R.

Multibeam (hydrosweep) swath bathymetric investigations revealed the presence of a NNW trending linear seamount chain along the axial part of the Laxmi Basin in the eastern Arabian Sea, between 15~'N, 70~'15'E and 17~'20'N, 69~'E. This chain...

Modeling of the branches of the Tsushima Warm Current in the eastern Japan sea

International Nuclear Information System (INIS)

Kawamura, Hideyuki; Ito, Toshimichi; Hirose, Naoki; Yoon, Jong-Hwan; Takikawa, Tetsutaro

2009-01-01

The branches of the Tsushima Warm Current (TWC) are realistically reproduced using a three-dimensional ocean general circulation model (OGCM). Simulated structures of the First Branch and the Second Branch of the TWC (FBTWC and SBTWC) in the eastern Japan Sea are mainly addressed in this study, being compared with measurement in the period September-October 2000. This is the first numerical experiment so far in which the OGCM is laterally exerted by real volume transports measured by acoustic Doppler current profiler (ADCP) through the Tsushima Straits and the Tsugaru Strait. In addition, sea level variation measured by tide-stations along the Japanese coast as well as satellite altimeters is assimilated into the OGCM through a sequential data assimilation method. It is demonstrated that the assimilation of sea level variation at the coastal tide-stations is useful in reproducing oceanic conditions in the nearshore region. We also examine the seasonal variation of the branches of the TWC in the eastern Japan Sea in 2000. It is suggested as a consequence that the FBTWC is continuous along northwestern Honshu Island in summertime, while it degenerates along the coast between the Sado Strait and the Oga Peninsula in other seasons. On the other hand, a mainstream of the SBTWC exists with meanders and eddies in the offshore region deeper than 1000 m to the north of the Sado Island throughout the year. (author)

Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment

KAUST Repository

Tsiola, A.; Pitta, P.; Fodelianakis, Stylianos; Pete, R.; Magiopoulos, I.; Mara, P.; Psarra, S.; Tanaka, T.; Mostajir, B.

2015-01-01

groups of the prokaryotic and eukaryotic (pico-, nano-, and micro-) plankton using a microcosm experiment during stratified water column conditions in the Cretan Sea (Eastern Mediterranean). Microcosms were enriched with N and P (either solely

Temperature, salinity, oxygen and other measurements collected in the Scotia Sea from 04 August 1997 to 05 September 1997 (NODC Accession 0000753)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and other data were collected using bottle and CTD casts in the Weddell and Scotia Sea from NATHANIEL B. PALMER. Data were collected from 04...

Indian Monsoon and denitrification change in the Laxmi Basin (IODP Exp. 355 Site U1456) of the Eastern Arabian Sea during the last 800 kyrs

Science.gov (United States)

Kim, J. E.; Khim, B. K.; Ikehara, M.; Lee, J.

2017-12-01

The Arabian Sea is a famous site for the basin-wide denitrification in the globe. The Western Arabian Sea has been acknowledged by its upwelling-induced denitrification related to the Indian Monsoon system (Altabet et al., 1999). It was recently reported that the denitrification in the Eastern Arabian Sea (IODP Exp. 355 Site U1456) has been persistent and consistent during the mid-Pleistocene as reflected in the bulk sediment δ15N values (Tripathi et al., 2017). Based on the age model reconstructed by δ18O stratigraphy of planktonic foraminifera (Globigerinoides ruber) together with shipboard biostratigraphic and paleomagnetic data at Site U1456 drilled in the Laxmi Basin of the Eastern Arabian Sea, the glacial-interglacial fluctuations of denitrification in association with the development of oxygen minimum zone (OMZ) were resolved in the context of Indian Monsoon activity. One of striking features in the Eastern Arabian Sea is that the δ15N values of bulk sediment show clear and consistent denitrification with minimum δ15N values exceeding 6‰ even during glacial periods, when its western counterpart experienced a temporal collapse of OMZ and denitrification. The Eastern Arabian Sea is fed not only by the upwelling-induced productivity in the western margin during the summer monsoon but also by the high productivity during the winter monsoon, both of which maintain the increased productivity affecting the OMZ through the consumption of dissolved oxygen by the degradation of sinking organic particles. The Eastern Arabian Sea is further influenced by the clockwise surface currents, intermediate water ventilation change by the blockage of Antarctic Intermediate Water, limited inflow from the Red Sea/Persian Gulf, and the freshwater salinity stratification due to nearby riverine discharges, all of which make the denitrification process more complicated than the Western Arabian Sea. Nonetheless, the glacial-interglacial denitrification change in the Eastern

Influence of Indian summer monsoon variability on the surface waves in the coastal regions of eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

SanilKumar, V.; Jesbin, G.

–885, 2016 www.ann-geophys.net/34/871/2016/ doi:10.5194/angeo-34-871-2016 © Author(s) 2016. CC Attribution 3.0 License. Influence of Indian summer monsoon variability on the surface waves in the coastal regions of eastern Arabian Sea V. Sanil Kumar and Jesbin... of the period. The annual average value is ∼ 1.5 m (Anoop et al., 2015). During the non-monsoon period, the land and sea breeze has a signif- icant influence on the wave climate of eastern AS (Glejin Ann. Geophys., 34, 871–885, 2016 www.ann-geophys.net/34...

Vertical distribution of mesozooplankton in the central and eastern Arabian Sea during the winter monsoons

Digital Repository Service at National Institute of Oceanography (India)

Padmavati, G.; Haridas, P.; Nair, K.K.C.; Gopalakrishnan, T.C.; Shiney, P.; Madhupratap, M.

The vertical distribution of mesozooplankton in the central and eastern Arabian Sea was investigated during the winter monsoon in 1995. Samples were analysed from discrete depth zones defined according to oxygen and temperature profiles of the water...

Characteristics of long-period swells measured in the near shore regions of eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Johnson, G.; SanilKumar, V.; Amrutha, M.M.; Singh, J.

Measured wave data covering two years simultaneously at 3 locations along the eastern Arabian Sea reveals the presence of long-period (peak wave period > 18 s) low-amplitude waves (significant wave height < 1 m) and the characteristics...

Polonium-210 and lead-210 in the Southern Polar Ocean: Naturally occurring tracers of biological and hydrographical processes in the surface waters of the Antarctic Circumpolar Current and the Weddell Sea; Polonium-210 und Blei-210 im Suedpolarmeer: Natuerliche Tracer fuer biologische und hydrographische Prozesse im Oberflaechenwasser des Antarktischen Zirkumpolarstroms und des Weddellmeeres

Energy Technology Data Exchange (ETDEWEB)

Friedrich, J.

1997-11-01

In this thesis the distribution of {sup 210}Po and {sup 210}Pb in the upper 600 m of the Antarctic Circumpolar Current and the Weddell Sea was investigated along north-south transects in austral spring and autumn. {sup 210}Po and {sup 210}Pb can serve as sensitive tracers for the special hydrographic conditions of the Antarctic Circumpolar Current and the Weddell Sea as well as for biological processes during phytoplankton blooms. The {sup 210}Po/{sup 210}Pb disequilibrium was used as a tracer for particle export. This tracer integrates export on a timescale of 276 days because of the 138 day half-life of {sup 210}Po and complements the {sup 234}Th/{sup 238}U disequilibrium as another tracer for plankton production and export on a shorter timescale of several weeks. (orig.) [Deutsch] In der vorliegenden Arbeit wurde die Verteilung von Blei-210 und seinem Enkelnuklid Polonium-210 im Antarktischen Zirkumpolarstrom und im Weddellmeer bis 600 m Tiefe in mehreren meridionalen Transekten im australen Fruehjahr und Herbst waehrend der `Polarstern`-Expeditionen ANT-X/6 und ANT-XI/4 untersucht. Die Verteilung von {sup 210}Pb und {sup 210}Po wird von mehreren Faktoren beeinflusst, sowohl durch die Advektion von Wassermassen im Antarktischen Zirkumpolarstrom und im Weddellmeer als auch von biologischen Prozessen z.B. innerhalb einer Planktonbluete. Bevor die Verteilungsmuster von {sup 210}Pb und {sup 210}Po jedoch als Tracer fuer einen Prozess genutzt werden koennen, muss der Effekt der einzelnen Faktoren auf die Verteilung betrachtet werden. (orig.)

Glaciotectonic deformations in the Jammerbugt and glaciodynamic development in the eastern North Sea

DEFF Research Database (Denmark)

Pedersen, Stig A. Schack; Boldreel, Lars Ole

2017-01-01

–Early Weichselian Skærumhede Group, indicating a Saalian age of the glaciotectonic deformation. The balancing of the thrust fault structures shows that the thrust sheets in the tailing end of the complex had their source in the Skagerrak sea. The hole caused by displacement contributed to formation of the Skagerrak......The Quaternary geology in the eastern part of the North Sea is characterized by large-scale glaciotectonic complexes. The northernmost complex is the Jammerbugt Glaciotectonic Complex here addressed, which occupies an area of more than 300km2. It was recently recognized during an investigation...... of conventional seismic profiles located about 10km offshore the west coast of northern Denmark. The deformed bedrock includes the main part of the Cretaceous Chalk Group in the North Sea. In the northern part of the complex the detachment surface is situated in Lower Cretaceous greensand about 400m below sea...

Acoustic-Trawl Survey of Walleye Pollock on the Eastern Bering Sea Shelf (DY1407, EK60)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC) conducted an acoustic-trawl (AT) stock assessment survey on the eastern Bering Sea...

Spatial and temporal variation of surface waves in shallow waters along the eastern Arabian Sea.

Digital Repository Service at National Institute of Oceanography (India)

Anoop, T.R.; SanilKumar, V.; Shanas, P.R.

We studied the spatial and temporal variation of surface waves along the eastern Arabian Sea during 2011 and 2012. Measured directional wave data at two shallow water locations and re-analysis datasets (ERA-Interim) at 0.751 intervals at four...

Coastal Sea Level along the North Eastern Atlantic Shelf from Delay Doppler Altimetry

Science.gov (United States)

Fenoglio-Marc, L.; Benveniste, J.; Andersen, O. B.; Gravelle, M.; Dinardo, S.; Uebbing, B.; Scharroo, R.; Kusche, J.; Kern, M.; Buchhaupt, C.

2017-12-01

Satellite altimetry data of the CryoSat-2 and Sentinel-3 missions processed with Delay Doppler methodology (DDA) provide improved coastal sea level measurements up to 2-4 km from coast, thanks to an along-track resolution of about 300m and a higher signal to noise ratio. We investigate the 10 Kilometre stripe along the North-Eastern Atlantic shelf from Lisbon to Bergen to detect the possible impacts in sea level change studies of this enhanced dataset. We consider SAR CryoSat-2 and Sentinel-3 altimetry products from the ESA GPOD processor and in-house reduced SAR altimetry (RDSAR) products. Improved processing includes in RDSAR the application of enhanced retrackers for the RDSAR waveform. Improved processing in SAR includes modification both in the generation of SAR waveforms, (as Hamming weighting window on the burst data prior to the azimuth FFT, zero-padding prior to the range FFT, doubling of the extension for the radar range swath) and in the SAMOSA2 retracker. Data cover the full lifetime of CryoSat-2 (6 years) and Sentinel-3 (1 year). Conventional altimetry are from the sea level CCI database. First we analyse the impact of these SAR altimeter data on the sea level trend and on the estimation of vertical motion from the altimeter minus tide gauge differences. VLM along the North-Eastern Atlantic shelf is generally small compared to the North-Western Atlantic Coast VLM, with a smaller signal to noise ratio. Second we investigate impact on the coastal mean sea level surface and the mean dynamic topography. We evaluate a mean surface from the new altimeter data to be combined to state of the art geoid models to derive the mean dynamic topography. We compare the results to existing oceanographic and geodetic mean dynamic topography solutions, both on grid and pointwise at the tide gauge stations. This study is supported by ESA through the Sea Level CCI and the GOCE++DYCOT projects

Neogene dinocyst zonation for the eastern North Sea Basin, Denmark

DEFF Research Database (Denmark)

Dybkjær, Karen; Piasecki, Stefan

2010-01-01

A dinocyst zonation for the Neogene succession in the eastern part of the North Sea Basin (Denmark) is presented. The zonation is based on an extensive database comprising data from more than fifty onshore and offshore boreholes and about twenty five outcrops. Most of the nineteen dinocyst zones......, of the Lower Miocene, and of the Upper Miocene and Pliocene successions. The previous zonation of the onshore Danish Middle Miocene is reconsidered and partly redefined. The zonation is correlated with other biostratigraphic subdivisions of the Neogene succession in the Danish region in addition to litho...

Seasonal Variations of Oceanographic Variables and Eastern Little Tuna (Euthynnus affinis) Catches in the North Indramayu Waters Java Sea

Science.gov (United States)

Syamsuddin, Mega; Sunarto; Yuliadi, Lintang

2018-02-01

The remotely derived oceanographic variables included sea surface temperature (SST), chlorophyll-a (Chl-a) and Eastern Little Tuna (Euthynnus affinis) catches are used as a combined dataset to understand the seasonal variation of oceanographic variables and Eastern Little Tuna catches in the north Indramayu waters, Java Sea. The fish catches and remotely sensed data were analysed for the 5 years datasets from 2010-2014. This study has shown the effect of monsoon inducing oceanographic condition in the study area. Seasonal change features were dominant for all the selected oceanographic parameters of SST and Chl-a, and also Eastern Little Tuna catches, respectively. The Eastern Little Tuna catch rates have the peak season from September to December (700 to 1000) ton that corresponded with the value of SST ranging from 29 °C to 30 °C following the decreasing of Chl-a concentrations in September to November (0.4 to 0.5) mg m-3. The monsoonal system plays a great role in determining the variability of oceanographic conditions and catch in the north Indramayu waters, Java Sea. The catches seemed higher during the northwest monsoon than in the southeast monsoon for all year observations except in 2010. The wavelet spectrum analysis results confirmed that Eastern Little Tuna catches had seasonal and inter-annual variations during 2012-2014. The SST had seasonal variations during 2010-2014. The Chl-a also showed seasonal variations during 2010-2011 and interannual variations during 2011-2014. Our results would benefit the fishermen and policy makers to have better management for sustainable catch in the study area.

The south-eastern North Sea : losses of vertebrate fauna during the past 2000 years

NARCIS (Netherlands)

Wolff, W.J.

At least 31 species of marine mammals, marine and coastal birds, and marine and anadromous fish have disappeared temporarily or permanently from the coasts of The Netherlands and in most cases also from the south-eastern North Sea (south of 54 degrees N) during the past 2000 years-In 18-22 cases,

Trophic ecology of deep-sea Asteroidea (Echinodermata) from eastern Canada

Science.gov (United States)

Gale, Katie S. P.; Hamel, Jean-François; Mercier, Annie

2013-10-01

Asteroids (sea stars) can be important predators in benthic communities and are often present in ecologically important and vulnerable deep-sea coral and sponge habitats. However, explicit studies on the trophic ecology of deep-sea asteroids are rare. We investigated the diets of seven species of deep-sea asteroid from the bathyal zone of Newfoundland and Labrador, eastern Canada. A multifaceted approach including live animal observations, stomach content analysis, and stable isotope analysis revealed the asteroids to be either top predators of megafauna or secondary consumers (mud ingesters, infaunal predators, and suspension feeders). The stable isotope signatures of Ceramaster granularis, Hippasteria phrygiana, and Mediaster bairdi are characteristic of high-level predators, having δ15N values 4.4‰ (more than one trophic level) above Ctenodiscus crispatus, Leptychaster arcticus, Novodinia americana, and Zoroaster fulgens. We present strong evidence that corals and sponges are common food items for two of the predatory species, C. granularis and H. phrygiana. During laboratory feeding trials, live H. phrygiana fed on several species of soft coral and C. granularis fed on sponges. Stomach content analysis of wild-caught individuals revealed sclerites from sea pens (e.g. Pennatula sp.) in the stomachs of both asteroid species; H. phrygiana also contained sclerites from at least two other species of octocoral and siliceous sponge spicules were present in the stomachs of C. granularis. The stomach contents of the secondary consumers contained a range of invertebrate material. Leptychaster arcticus and Ctenodiscus crispatus feed infaunally on bulk sediment and molluscs, Zoroaster fulgens is a generalist infaunal predator, and the brisingid Novodinia americana is a specialist suspension feeder on benthopelagic crustaceans. This study provides a foundation for understanding the ecological roles of bathyal asteroids, and suggests that some species may have the

Biogeochemical relationships between ultrafiltered dissolved organic matter and picoplankton activity in the Eastern Mediterranean Sea

NARCIS (Netherlands)

Meador, Travis B.; Gogou, Alexandra; Spyres, Georgina; Herndl, Gerhard J.; Krasakopoulou, Evangelia; Psarra, Stella; Yokokawa, Taichi; De Corte, Daniele; Zervakis, Vassilis; Repeta, Daniel J.

2010-01-01

We targeted the warm, subsurface waters of the Eastern Mediterranean Sea (EMS) to investigate processes that are linked to the chemical composition and cycling of dissolved organic carbon (DOC) in seawater. The apparent respiration of semi-labile DOC accounted for 27 +/- 18% of oxygen consumption in

Indian Ocean dipole modulated wave climate of eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Anoop, T.R.; SanilKumar, V.; Shanas, P.R.; Glejin, J.; Amrutha, M.M.

–378, 2016 www.ocean-sci.net/12/369/2016/ doi:10.5194/os-12-369-2016 © Author(s) 2016. CC Attribution 3.0 License. Indian Ocean Dipole modulated wave climate of eastern Arabian Sea T. R. Anoop1, V. Sanil Kumar1, P. R. Shanas1,2, J. Glejin1, and M. M. Amrutha1... are available on the website of the Japanese Agency of Marine–Earth Science and Technology (www.jamstec.go.jp). The tropical IO displays strong inter-annual climate vari- ability associated with the El Niño–Southern Oscillation (ENSO) and the IOD (Murtugudde et...

Crustal architecture of the eastern margin of Japan Sea: back-arc basin opening and contraction

Science.gov (United States)

No, T.; Sato, T.; Takahashi, N.; Kodaira, S.; Kaneda, Y.; Ishiyama, T.; Sato, H.

2012-12-01

Although large earthquakes such as the 1964 Niigata earthquake (M 7.5), 1983 Nihonkai-Chubu earthquake (M 7.8), and 1993 Hokkaido Nansei-Oki earthquake (M 7.8) have caused large amounts of damage to the eastern margin of the Japan Sea, a substantial number of seismic studies have been conducted for the seismogenic zone on the Pacific Ocean side of Japan. In addition, the detail of the source fault model for the eastern margin of the Japan Sea is not well defined for all cases. This highlights the need for further studies to investigate seismic imaging. Therefore, we have collaborated with other Japanese research institutions for a project titled "Priority Investigations of Strain Concentration Areas" (which is funded by Special Coordination Funds for Promoting Science and Technology, Japan). This project has conducted seismic surveys from 2009 to 2012 using the deep-sea research vessel, Kairei, from the Japan Agency for Marine-Earth Science and Technology. There is a strain concentration area in the eastern part of the survey area (Okamura et al., 1995). The western part of the survey area includes the Yamato Basin and Japan Basin. It is very important to study the crustal structure in the seismotectonic studies of the eastern margin of the Japan Sea. We conducted a marine seismic survey by using a multichannel seismic (MCS) system and ocean bottom seismographs (OBSs) along the eastern margin of the Japan Sea. Seismic data were acquired along 42 lines with a total length of approximately 9,000 km. The following results were obtained from seismic imaging. On the basis of the results of the MCS imaging, active reverse faults and folds were observed in the margin of the Toyama Trough; however, the sedimentary layers in the trough were flat. In the sedimentary layers and crusts of the Sado Ridge, Mogami Trough, and source area of the 1964 Niigata earthquake located north of the Sado Island, greater deformation was observed. The deformation weakened toward the Yamato

Diet compositions and trophic guild structure of the eastern Chukchi Sea demersal fish community

Science.gov (United States)

Whitehouse, George A.; Buckley, Troy W.; Danielson, Seth L.

2017-01-01

Fishes are an important link in Arctic marine food webs, connecting production of lower trophic levels to apex predators. We analyzed 1773 stomach samples from 39 fish species collected during a bottom trawl survey of the eastern Chukchi Sea in the summer of 2012. We used hierarchical cluster analysis of diet dissimilarities on 21 of the most well sampled species to identify four distinct trophic guilds: gammarid amphipod consumers, benthic invertebrate generalists, fish and shrimp consumers, and zooplankton consumers. The trophic guilds reflect dominant prey types in predator diets. We used constrained analysis of principal coordinates (CAP) to determine if variation within the composite guild diets could be explained by a suite of non-diet variables. All CAP models explained a significant proportion of the variance in the diet matrices, ranging from 7% to 25% of the total variation. Explanatory variables tested included latitude, longitude, predator length, depth, and water mass. These results indicate a trophic guild structure is present amongst the demersal fish community during summer in the eastern Chukchi Sea. Regular monitoring of the food habits of the demersal fish community will be required to improve our understanding of the spatial, temporal, and interannual variation in diet composition, and to improve our ability to identify and predict the impacts of climate change and commercial development on the structure and functioning of the Chukchi Sea ecosystem.

Offshore limit of coastal ocean variability identified from hydrography and altimeter data in the eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Antony, M.K.; Swamy, G.N.; Somayajulu, Y.K.

In this communication, we describe a hitherto-unknown offshore limit to the coastal ocean variability signatures away from the continental shelf in the eastern Arabian Sea, based on hydrographic observations and satellite altimeter (TOPEX...

AFSC/NMML: Cetacean line-transect survey in the eastern Bering Sea shelf; 1999, 2000, 2002, and 2004

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Visual surveys for cetaceans were conducted on the eastern Bering Sea shelf along transect lines, in association with the AFSC.s echo integration trawl surveys for...

Multidisciplinary oil spill modeling to protect coastal communities and the environment of the Eastern Mediterranean Sea

Science.gov (United States)

Alves, Tiago M.; Kokinou, Eleni; Zodiatis, George; Radhakrishnan, Hari; Panagiotakis, Costas; Lardner, Robin

2016-11-01

We present new mathematical and geological models to assist civil protection authorities in the mitigation of potential oil spill accidents in the Eastern Mediterranean Sea. Oil spill simulations for 19 existing offshore wells were carried out based on novel and high resolution bathymetric, meteorological, oceanographic, and geomorphological data. The simulations show a trend for east and northeast movement of oil spills into the Levantine Basin, affecting the coastal areas of Israel, Lebanon and Syria. Oil slicks will reach the coast in 1 to 20 days, driven by the action of the winds, currents and waves. By applying a qualitative analysis, seabed morphology is for the first time related to the direction of the oil slick expansion, as it is able to alter the movement of sea currents. Specifically, the direction of the major axis of the oil spills, in most of the cases examined, is oriented according to the prevailing azimuth of bathymetric features. This work suggests that oil spills in the Eastern Mediterranean Sea should be mitigated in the very few hours after their onset, and before wind and currents disperse them. We explain that protocols should be prioritized between neighboring countries to mitigate any oil spills.

Comparison of ERA-Interim waves with buoy data in the eastern Arabian Sea during high waves

Digital Repository Service at National Institute of Oceanography (India)

Shanas, P.R.; SanilKumar, V.

at two locations in eastern Arabian Sea One location is a deep water location and another one is a shallow water location The comparison of significant wave height (SWH) between ERA dataset and buoy data at both the locations shows good correlation...

Northward advection of Atlantic water in the eastern Nordic Seas over the last 3000 yr

Directory of Open Access Journals (Sweden)

C. V. Dylmer

2013-07-01

Full Text Available Three marine sediment cores distributed along the Norwegian (MD95-2011, Barents Sea (JM09-KA11-GC, and Svalbard (HH11-134-BC continental margins have been investigated in order to reconstruct changes in the poleward flow of Atlantic waters (AW and in the nature of upper surface water masses within the eastern Nordic Seas over the last 3000 yr. These reconstructions are based on a limited set of coccolith proxies: the abundance ratio between Emiliania huxleyi and Coccolithus pelagicus, an index of Atlantic vs. Polar/Arctic surface water masses; and Gephyrocapsa muellerae, a drifted coccolith species from the temperate North Atlantic, whose abundance changes are related to variations in the strength of the North Atlantic Current. The entire investigated area, from 66 to 77° N, was affected by an overall increase in AW flow from 3000 cal yr BP (before present to the present. The long-term modulation of westerlies' strength and location, which are essentially driven by the dominant mode of the North Atlantic Oscillation (NAO, is thought to explain the observed dynamics of poleward AW flow. The same mechanism also reconciles the recorded opposite zonal shifts in the location of the Arctic front between the area off western Norway and the western Barents Sea–eastern Fram Strait region. The Little Ice Age (LIA was governed by deteriorating conditions, with Arctic/Polar waters dominating in the surface off western Svalbard and western Barents Sea, possibly associated with both severe sea ice conditions and a strongly reduced AW strength. A sudden short pulse of resumed high WSC (West Spitsbergen Current flow interrupted this cold spell in eastern Fram Strait from 330 to 410 cal yr BP. Our dataset not only confirms the high amplitude warming of surface waters at the turn of the 19th century off western Svalbard, it also shows that such a warming was primarily induced by an excess flow of AW which stands as unprecedented over the last 3000 yr.

Temperature, salinity, and dissolved oxygen profile data from MULTIPLE SHIPS in the Eastern Mediterranean Sea: (NODC Accession 9400176)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Conductivity, Temperature and Depth (CTD) and other data were collected in Mediterranean Sea, Eastern Basin as part of Mediterranean Ocean Circulation project. Data...

The Ross Sea Dipole - temperature, snow accumulation and sea ice variability in the Ross Sea region, Antarctica, over the past 2700 years

Science.gov (United States)

Bertler, Nancy A. N.; Conway, Howard; Dahl-Jensen, Dorthe; Emanuelsson, Daniel B.; Winstrup, Mai; Vallelonga, Paul T.; Lee, James E.; Brook, Ed J.; Severinghaus, Jeffrey P.; Fudge, Taylor J.; Keller, Elizabeth D.; Baisden, W. Troy; Hindmarsh, Richard C. A.; Neff, Peter D.; Blunier, Thomas; Edwards, Ross; Mayewski, Paul A.; Kipfstuhl, Sepp; Buizert, Christo; Canessa, Silvia; Dadic, Ruzica; Kjær, Helle A.; Kurbatov, Andrei; Zhang, Dongqi; Waddington, Edwin D.; Baccolo, Giovanni; Beers, Thomas; Brightley, Hannah J.; Carter, Lionel; Clemens-Sewall, David; Ciobanu, Viorela G.; Delmonte, Barbara; Eling, Lukas; Ellis, Aja; Ganesh, Shruthi; Golledge, Nicholas R.; Haines, Skylar; Handley, Michael; Hawley, Robert L.; Hogan, Chad M.; Johnson, Katelyn M.; Korotkikh, Elena; Lowry, Daniel P.; Mandeno, Darcy; McKay, Robert M.; Menking, James A.; Naish, Timothy R.; Noerling, Caroline; Ollive, Agathe; Orsi, Anaïs; Proemse, Bernadette C.; Pyne, Alexander R.; Pyne, Rebecca L.; Renwick, James; Scherer, Reed P.; Semper, Stefanie; Simonsen, Marius; Sneed, Sharon B.; Steig, Eric J.; Tuohy, Andrea; Ulayottil Venugopal, Abhijith; Valero-Delgado, Fernando; Venkatesh, Janani; Wang, Feitang; Wang, Shimeng; Winski, Dominic A.; Winton, V. Holly L.; Whiteford, Arran; Xiao, Cunde; Yang, Jiao; Zhang, Xin

2018-02-01

High-resolution, well-dated climate archives provide an opportunity to investigate the dynamic interactions of climate patterns relevant for future projections. Here, we present data from a new, annually dated ice core record from the eastern Ross Sea, named the Roosevelt Island Climate Evolution (RICE) ice core. Comparison of this record with climate reanalysis data for the 1979-2012 interval shows that RICE reliably captures temperature and snow precipitation variability in the region. Trends over the past 2700 years in RICE are shown to be distinct from those in West Antarctica and the western Ross Sea captured by other ice cores. For most of this interval, the eastern Ross Sea was warming (or showing isotopic enrichment for other reasons), with increased snow accumulation and perhaps decreased sea ice concentration. However, West Antarctica cooled and the western Ross Sea showed no significant isotope temperature trend. This pattern here is referred to as the Ross Sea Dipole. Notably, during the Little Ice Age, West Antarctica and the western Ross Sea experienced colder than average temperatures, while the eastern Ross Sea underwent a period of warming or increased isotopic enrichment. From the 17th century onwards, this dipole relationship changed. All three regions show current warming, with snow accumulation declining in West Antarctica and the eastern Ross Sea but increasing in the western Ross Sea. We interpret this pattern as reflecting an increase in sea ice in the eastern Ross Sea with perhaps the establishment of a modern Roosevelt Island polynya as a local moisture source for RICE.

Climatology of the Eastern Arabian Sea during the last glacial cycle reconstructed from paired measurement of foraminiferal delta sup(18)O and Mg/Ca

Digital Repository Service at National Institute of Oceanography (India)

Banakar, V.K.; Mahesh, B.S.; Burr, G.; Chodankar, A

Paired measurements of Mg/Ca and delta sup(18)O of Globigerenoides sacculifer from an Eastern Arabian Sea (EAS) sediment core indicate that sea-surface temperature (SST) varied within 2 degrees C and sea-surface salinity within 2 psu during the last...

Variability and connectivity of plaice populations from the Eastern North Sea to the Baltic Sea, part II. Biological evidence of population mixing

DEFF Research Database (Denmark)

Ulrich, Clara; Hansen, Jakob Hemmer; Boje, Jesper

2016-01-01

in parallel. Genetic markers suggested the existence of different genetic populations in the transition area. Growth backcalculation with otoliths resulted in significant although limited differences in growth rates between North Sea and Skagerrak, indicating weak differentiation or important mixing......A multi-disciplinary study was conducted to clarify stock identity and connectivity patterns in the populations of European plaice (Pleuronectes platessa) in the Skagerrak-Kattegat transition area between the Eastern North Sea and the Baltic Sea. Five independent biological studies were carried out...... constitute a large share of the catches in this area. The mixing of different populations within a management area has implications for stock assessment and management. Choice must be made to either lump or split the populations, and the feasibility and constraints of both options are discussed. The outcomes...

Variation of paleo-productivity and terrigenous input in the eastern Arabian Sea during the past 100 ka

Digital Repository Service at National Institute of Oceanography (India)

Ishfaq, A.M.; Pattan, J.N.; Matta, V.M.; Banakar, V.K.

A 4.1m long sediment core from the eastern Arabian Sea is studied using multiple geochemical proxies to understand the variation of productivity and terrigenous matter supply during the past 100 ka. The temporal variation in element concentration...

Data from investigation on seismic Sea-waves events in the Eastern Mediterranean from the Birth of Christ to 500 A.D.

Directory of Open Access Journals (Sweden)

J. ANTONOPOULOS

1980-06-01

Full Text Available The Eastern Mediterranean has a long history of damaging seismic sea
waves (Tsunamis but a great number of them which are locally generated are small. They have caused no serious damage to the coasts because their
energy is confined by many islands of the Greek Archipelagos. However,
some of them have been rather severe and destructive to property and
human life.
This paper is comprised of data from an investigation into the activity
of seismic sea waves in the Eastern Mediterranean from the Birth of
Christ to 500 A.D. It contains a great amount of information concerning
earthquakes, volcanic eruptions and seismic sea waves.
All the available information has been compiled from historical accounts,
archives, press reports, magazines and related works.

Early- to late-Holocene contrast in productivity, OMZ intensity and calcite dissolution in the eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Naik, S.S.; Godad, S.P.; Naidu, P.D.; Tiwari, M.; Paropkari, A.L.

) Concentrations and burial fluxes of organic and inorganic carbon on the eastern margins of the Arabian Sea. Marine Geology 178: 95-112. Böning P, and Bard E (2009) Millennial/centennial-scale thermocline ventilation changes in the Indian Ocean as reflected...

Rapid invasion of anthropogenic CO2 into the deep circulation of the Weddell Gyre

NARCIS (Netherlands)

van Heuven, Steven M. A. C.; Hoppema, Mario; Jones, Elisabeth Marie; de Baar, Henricus

2014-01-01

Data are presented for total carbon dioxide (TCO2), oxygen and nutrients from 14 cruises covering two repeat sections across the Weddell Gyre, from 1973 to 2010. Assessments of the rate of increase in anthropogenic CO2 (C-ant) are made at three locations. Along the Prime Meridian, TCO2 is observed

Flatfish recruitment response to decadal climatic variability and ocean conditions in the eastern Bering Sea

Science.gov (United States)

Wilderbuer, T. K.; Hollowed, A. B.; Ingraham, W. J.; Spencer, P. D.; Conners, M. E.; Bond, N. A.; Walters, G. E.

2002-10-01

This paper provides a retrospective analysis of the relationship of physical oceanography and biology and recruitment of three Eastern Bering Sea flatfish stocks: flathead sole ( Hippoglossoides elassodon), northern rock sole ( Lepidopsetta polyxystra), and arrowtooth flounder ( Atheresthes stomias) for the period 1978-1996. Temporal trends in flatfish production in the Eastern Bering Sea are consistent with the hypothesis that decadal scale climate variability influences marine survival during the early life history period. Density-dependence (spawning stock size) is statistically significant in a Ricker model of flatfish recruitment, which includes environmental terms. Wind-driven advection of flatfish larvae to favorable nursery grounds was also found to coincide with years of above-average recruitment through the use of an ocean surface current simulation model (OSCURS). Ocean forcing of Bristol Bay surface waters during springtime was mostly shoreward (eastward) during the 1980s and seaward (westerly) during the 1990s, corresponding with periods of good and poor recruitment. Distance from shore and water depth at the endpoint of 90-day drift periods (estimated time of settlement) were also found to correspond with flatfish productivity.

The Ross Sea Dipole – temperature, snow accumulation and sea ice variability in the Ross Sea region, Antarctica, over the past 2700 years

Directory of Open Access Journals (Sweden)

N. A. N. Bertler

2018-02-01

Full Text Available High-resolution, well-dated climate archives provide an opportunity to investigate the dynamic interactions of climate patterns relevant for future projections. Here, we present data from a new, annually dated ice core record from the eastern Ross Sea, named the Roosevelt Island Climate Evolution (RICE ice core. Comparison of this record with climate reanalysis data for the 1979–2012 interval shows that RICE reliably captures temperature and snow precipitation variability in the region. Trends over the past 2700 years in RICE are shown to be distinct from those in West Antarctica and the western Ross Sea captured by other ice cores. For most of this interval, the eastern Ross Sea was warming (or showing isotopic enrichment for other reasons, with increased snow accumulation and perhaps decreased sea ice concentration. However, West Antarctica cooled and the western Ross Sea showed no significant isotope temperature trend. This pattern here is referred to as the Ross Sea Dipole. Notably, during the Little Ice Age, West Antarctica and the western Ross Sea experienced colder than average temperatures, while the eastern Ross Sea underwent a period of warming or increased isotopic enrichment. From the 17th century onwards, this dipole relationship changed. All three regions show current warming, with snow accumulation declining in West Antarctica and the eastern Ross Sea but increasing in the western Ross Sea. We interpret this pattern as reflecting an increase in sea ice in the eastern Ross Sea with perhaps the establishment of a modern Roosevelt Island polynya as a local moisture source for RICE.

A glimpse beneath Antarctic sea ice: observation of platelet-layer thickness and ice-volume fraction with multi-frequency EM

Science.gov (United States)

Hendricks, S.; Hoppmann, M.; Hunkeler, P. A.; Kalscheuer, T.; Gerdes, R.

2015-12-01

In Antarctica, ice crystals (platelets) form and grow in supercooled waters below ice shelves. These platelets rise and accumulate beneath nearby sea ice to form a several meter thick sub-ice platelet layer. This special ice type is a unique habitat, influences sea-ice mass and energy balance, and its volume can be interpreted as an indicator for ice - ocean interactions. Although progress has been made in determining and understanding its spatio-temporal variability based on point measurements, an investigation of this phenomenon on a larger scale remains a challenge due to logistical constraints and a lack of suitable methodology. In the present study, we applied a lateral constrained Marquardt-Levenberg inversion to a unique multi-frequency electromagnetic (EM) induction sounding dataset obtained on the ice-shelf influenced fast-ice regime of Atka Bay, eastern Weddell Sea. We adapted the inversion algorithm to incorporate a sensor specific signal bias, and confirmed the reliability of the algorithm by performing a sensitivity study using synthetic data. We inverted the field data for sea-ice and sub-ice platelet-layer thickness and electrical conductivity, and calculated ice-volume fractions from platelet-layer conductivities using Archie's Law. The thickness results agreed well with drill-hole validation datasets within the uncertainty range, and the ice-volume fraction also yielded plausible results. Our findings imply that multi-frequency EM induction sounding is a suitable approach to efficiently map sea-ice and platelet-layer properties. However, we emphasize that the successful application of this technique requires a break with traditional EM sensor calibration strategies due to the need of absolute calibration with respect to a physical forward model.

Differential growth of larval sprat Sprattus sprattus across a tidal front in the eastern North Sea

DEFF Research Database (Denmark)

Munk, Peter

1993-01-01

Spatial variations in abundance and growth of larval sprat Sprattus sprattus L. were examined across a tidal front in the eastern North Sea, off the west coast of Denmark. The aim of the study was to evaluate the potential advantage for sprat larvae of residing in the vicinity of a tidal front...

Indo-Pacific sea surface temperature influences on failed consecutive rainy seasons over eastern Africa

Science.gov (United States)

Hoell, Andrew; Funk, Christopher C.

2014-01-01

Rainfall over eastern Africa (10°S–10°N; 35°E–50°E) is bimodal, with seasonal maxima during the "long rains" of March–April–May (MAM) and the "short rains" of October–November–December (OND). Below average precipitation during consecutive long and short rains seasons over eastern Africa can have devastating long-term impacts on water availability and agriculture. Here, we examine the forcing of drought during consecutive long and short rains seasons over eastern Africa by Indo-Pacific sea surface temperatures (SSTs). The forcing of eastern Africa precipitation and circulation by SSTs is tested using ten ensemble simulations of a global weather forecast model forced by 1950–2010 observed global SSTs. Since the 1980s, Indo-Pacific SSTs have forced more frequent droughts spanning consecutive long and short rains seasons over eastern Africa. The increased frequency of dry conditions is linked to warming SSTs over the Indo-west Pacific and to a lesser degree to Pacific Decadal Variability. During MAM, long-term warming of tropical west Pacific SSTs from 1950–2010 has forced statistically significant precipitation reductions over eastern Africa. The warming west Pacific SSTs have forced changes in the regional lower tropospheric circulation by weakening the Somali Jet, which has reduced moisture and rainfall over the Horn of Africa. During OND, reductions in precipitation over recent decades are oftentimes overshadowed by strong year-to-year precipitation variability forced by the Indian Ocean Dipole and the El Niño–Southern Oscillation.

Contrasting recruitment seasonality of sea urchin species in Gran Canaria, Canary Islands (eastern Atlantic

Directory of Open Access Journals (Sweden)

S. GARCIA-SANZ

2014-03-01

Full Text Available Despite sea-urchins can play an important role affecting the community structure of subtidal bottoms, factors controlling the dynamics of sea-urchin populations are still poorly understood. We assessed the seasonal variation in recruitment of three sea-urchin species (Diadema africanum, Paracentrotus lividus and Arbacia lixula at Gran Canaria Island (eastern Atlantic via monthly deployment of artificial collectors throughout an entire annual cycle on each of four adjacent habitat patches (seagrasses, sandy patches, ‘urchin-grazed’ barrens and macroalgal-dominated beds within a shallow coastal landscape. Paracentrotus lividus and A. lixula had exclusively one main recruitment peak in late winter-spring. Diadema africanum recruitment was also seasonal, but recruits appeared in late summer-autumn, particularly on ‘urchin-grazed’ barrens with large abundances of adult conspecifics. In conclusion, this study has demonstrated non-overlapping seasonal recruitment patterns of the less abundant species (P. lividus and A. lixula with the most conspicuous species (D. africanum in the study area.

Shipboard measurements of nitrogen dioxide, nitrous acid, nitric acid and ozone in the Eastern Mediterranean Sea

Czech Academy of Sciences Publication Activity Database

Večeřa, Zbyněk; Mikuška, Pavel; Smolík, Jiří; Eleftheriadis, K.; Bryant, C.; Colbeck, I.; Lazaridis, M.

2008-01-01

Roč. 8, č. 1 (2008), s. 117-125 ISSN 1567-7230 Grant - others:5th FP Commission of the EC(XE) EVK2-CT-1999-0052 SUB-AERO Institutional research plan: CEZ:AV0Z40310501; CEZ:AV0Z40720504 Keywords : reactive nitrogen species * ozone * Eastern Mediterranean Sea Subject RIV: CB - Analytical Chemistry, Separation

Aerosol sources and their contribution to the chemical composition of aerosols in the Eastern Mediterranean Sea during summertime

Directory of Open Access Journals (Sweden)

J. Sciare

2003-01-01

Full Text Available A detailed study on the temporal variability of compounds important in controlling aerosol chemical composition was performed during a one-month experiment conducted during summer 2000 at a background site on Crete, in the Eastern Mediterranean Sea. Contribution of different aerosol sources in the Eastern Mediterranean Basin could be investigated at this location since the site is influenced by a wide range of air masses originating mainly in Europe and Africa. Chemical apportionment was performed for various air mass origins and showed a strong impact of anthropogenic emissions in the Turkey and Central Europe sectors, with black carbon (BC and non-sea-salt sulfate (nss-SO4 concentrations higher than observed in the Eastern and Western Europe sectors. High levels of non-sea-salt calcium (nss-Ca were associated with air masses from Africa but also from Central Turkey. Evidence was found that BC calculation based on light absorbance during dust events was biased. This quality-controlled high temporal resolution dataset allowed to investigate in detail the source-receptor relationships responsible for the levels of BC, nss-SO4 and sulfur dioxide (SO2, observed in Crete. Among the results obtained from this model, the major contribution of Turkey and Central Europe was confirmed in terms of anthropogenic emissions. Comparisons with remote optical properties obtained from Satellite observations (SEAWIFS north of Crete indicates that our ground based aerosol characterization was suitable for describing aerosol properties in the atmospheric column for most of the time during the campaign.

Early Permian intrusions in the Paleozoic sediments of the Eastern North Sea area

DEFF Research Database (Denmark)

Clausen, O.R.; Andresen, Katrine Juul; Rasmussen, Jens Andreas

in the Northern Permian Basin which in the eastern North Sea is separated from the Southern Permian Basin by the Ringkøbing-Fyn High. The Permian basins were initiated during thermal subsidence following a late Carboniferous- early Permian rifting phase associated with extensive igneous activity recorded across...... the entire North Sea Basin. The easternmost intrusions and extrusions have been associated to the “Skagerrak-Centered Large Igneous Province” that has an early Permian age of c. 297 Ma. Compared to the Southern Permian Basin which historically has been intensely investigated because of the known presence...... of hydrocarbons within the Paleozoic sediments, the Northern Permian Basin has gained much less interest outside the hydrocarbon producing Mesozoic graben systems. This is mainly due to an apparent lack of potential source rocks. A major E-W striking northward dipping fault system characterizes the study area...

Gouge marks on deep-sea mud volcanoes in the eastern Mediterranean: Caused by Cuvier’s beaked whales?

NARCIS (Netherlands)

Woodside, J.M.; David, L; Frantzis, A.; Hooker, S.K.

2006-01-01

Enigmatic seafloor gouge marks at depths of 1700-2100 m have been observed from submersible during geological survey work studying mud volcanoes in the eastern Mediterranean Sea. The marks consist of a central groove (about 10 cm deep and 1-2 m long), superimposed on a broader bowl-shaped depression

On an upwelling front, propagation of upwelling and vertical velocity in the eastern Arabian sea during monsoon, 1987

Digital Repository Service at National Institute of Oceanography (India)

Antony, M.K.; Unnikrishnan, A.S.

A coastal upwelling front parallel to the coast and identifiable upto a depth of 75 m was observed between 12.5 and 16 degrees N along the eastern Arabian Sea in September, 1987 from closely spaced digital BT data. With a north-south slope...

Biochemical biomarker responses to pollution in selected sentinel organisms across the Eastern Mediterranean and the Black Sea

KAUST Repository

Tsangaris, Catherine; Moschino, Vanessa; Strogyloudi, Evangelia; Coatu, Valentina; Ramšak, Andreja; Abu Alhaija, Rana; Carvalho, Susana; Felline, Serena; Kosyan, Alisa; Lazarou, Yiota; Hatzianestis, Ioannis; Oros, Andra; Tiganus, Daniela

2015-01-01

Pollution effects were assessed by means of biochemical biomarkers (catalase, glutathione S-transferase and acetylcholinesterase activities, and metallothioneins content) in five species at selected coastal sites across the Eastern Mediterranean and the Black Sea. The mussel Mytilus galloprovincialis, a well-established sentinel species, was investigated in the Adriatic Sea, Aegean Sea, and Black Sea. The mussel Brachidontes pharaonis and the striped red mullet Mullus surmuletus were used in the Levantine Sea where M. galloprovincialis is not present. The white seabream Diplodus sargus sargus and the gastropod Rapana venosa were additionally sampled in the Adriatic and the Black Sea, respectively. Mussels showed catalase, glutathione S-transferase, and acetylcholinesterase responses to pollution in most geographical areas while the response of metallothioneins was restricted to a few sites. R. venosa showed marked responses of catalase and metallothioneins whereas both fish species did not generally exhibit variations in biomarker values among sites. The approach based on the reference deviation concept using the “Integrated Biological Responses version 2” index was useful for the interpretation of overall biomarker responses.

Biochemical biomarker responses to pollution in selected sentinel organisms across the Eastern Mediterranean and the Black Sea

KAUST Repository

Tsangaris, Catherine

2015-09-23

Pollution effects were assessed by means of biochemical biomarkers (catalase, glutathione S-transferase and acetylcholinesterase activities, and metallothioneins content) in five species at selected coastal sites across the Eastern Mediterranean and the Black Sea. The mussel Mytilus galloprovincialis, a well-established sentinel species, was investigated in the Adriatic Sea, Aegean Sea, and Black Sea. The mussel Brachidontes pharaonis and the striped red mullet Mullus surmuletus were used in the Levantine Sea where M. galloprovincialis is not present. The white seabream Diplodus sargus sargus and the gastropod Rapana venosa were additionally sampled in the Adriatic and the Black Sea, respectively. Mussels showed catalase, glutathione S-transferase, and acetylcholinesterase responses to pollution in most geographical areas while the response of metallothioneins was restricted to a few sites. R. venosa showed marked responses of catalase and metallothioneins whereas both fish species did not generally exhibit variations in biomarker values among sites. The approach based on the reference deviation concept using the “Integrated Biological Responses version 2” index was useful for the interpretation of overall biomarker responses.

Biochemical biomarker responses to pollution in selected sentinel organisms across the Eastern Mediterranean and the Black Sea.

Science.gov (United States)

Tsangaris, Catherine; Moschino, Vanessa; Strogyloudi, Evangelia; Coatu, Valentina; Ramšak, Andreja; Alhaija, Rana Abu; Carvalho, Susana; Felline, Serena; Kosyan, Alisa; Lazarou, Yiota; Hatzianestis, Ioannis; Oros, Andra; Tiganus, Daniela

2016-01-01

Pollution effects were assessed by means of biochemical biomarkers (catalase, glutathione S-transferase and acetylcholinesterase activities, and metallothioneins content) in five species at selected coastal sites across the Eastern Mediterranean and the Black Sea. The mussel Mytilus galloprovincialis, a well-established sentinel species, was investigated in the Adriatic Sea, Aegean Sea, and Black Sea. The mussel Brachidontes pharaonis and the striped red mullet Mullus surmuletus were used in the Levantine Sea where M. galloprovincialis is not present. The white seabream Diplodus sargus sargus and the gastropod Rapana venosa were additionally sampled in the Adriatic and the Black Sea, respectively. Mussels showed catalase, glutathione S-transferase, and acetylcholinesterase responses to pollution in most geographical areas while the response of metallothioneins was restricted to a few sites. R. venosa showed marked responses of catalase and metallothioneins whereas both fish species did not generally exhibit variations in biomarker values among sites. The approach based on the reference deviation concept using the "Integrated Biological Responses version 2" index was useful for the interpretation of overall biomarker responses.

AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service Annual Eastern Bering Sea Summer Bottom Trawl Surveys 1975 - 2015

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains detailed crab data collected from the annual NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the eastern Bering Sea continental...

Evaluating the impact of atmospheric depositions on springtime dinitrogen fixation in the Cretan Sea (Eastern Mediterranean - A mesocosm approach

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Eyal Rahav

2016-09-01

Full Text Available Large amounts of dust and atmospheric aerosols, originating from surrounding desert areas (e.g., Sahara and Middle East are deposited annually on the surface of the Eastern Mediterranean Sea. These depositions can provide high amounts of micro (such as Fe, Zn, Co and macro nutrients (such as P and N to supplement nutrient-poor surface waters- that typically limit primary productivity and also dinitrogen (N2 fixation in many marine environments. Here, we studied the impact of the atmospheric deposition of dust and aerosols on N2 fixation in the Cretan Sea (Eastern Mediterranean Sea. Mixed polluted aerosols (hereafter A and Saharan dust (hereafter SD were added to nine mesocosms (3-m3 each containing surface mixed layer seawater (~10 m, and N2 fixation was evaluated for 6 days during May 2012 (springtime. The addition of SD triggered a rapid (30 h and robust (2-4 fold increase in N2 fixation rates that remained high for 6 days and contributed 3-8% of the primary productivity. The A addition also resulted in higher N2 fixation rates compared to the unamended control mesocosms, although the responses were less profound (1.5-2 fold and accounted for only 2-4% of the primary productivity. The microbial community responded differently to the two additions. Heterotrophic bacterial N2 fixers dominated the diazotroph community in A and the control mesocosms, while the non-filamentous cyanobacterial group Trichodesmium prevailed in the SD treatment (68% of all the operational taxonomic units, verified by qPCR analyses. Our results indicate that the aerosol source, its route prior to deposition, and its specific chemical composition, can alter the diazotrophic diversity and activity in the Eastern Mediterranean Sea and may thus impact both the N and C dynamics in this impoverished environment.

Methane-related authigenic carbonates of the eastern Mediterranean Sea mud volcanoes and their possible relation to gas hydrate destabilisation

NARCIS (Netherlands)

Aloisi, G; Pierre, C; Rouchy, J.-M.; Foucher, J.P.; Woodside, J.M.; MEDINAUT scientific party, NN

2000-01-01

Nautile submersible investigations of mud volcanoes and brine seep areas of the eastern Mediterranean Sea during the MEDINAUT cruise in November 1998 discovered extensive areas of authigenic carbonate crusts associated with methane emissions. Carbonate crusts form pavements, round slabs and circular

Spatial patterns of bacterial abundance, activity and community composition in relation to water masses in the eastern Mediterranean Sea

NARCIS (Netherlands)

Yokokawa, Taichi; De Corte, Daniele; Sintes, Eva; Herndl, Gerhard J.

2010-01-01

To determine the variation of bacterial activity and community composition between and within specific water masses, samples were collected throughout the water column at 5 stations in the eastern Mediterranean Sea corresponding to the regions of the northern Aegean, mid-Aegean, western Cretan,

Assessment of microphysical and chemical factors of aerosols over seas of the Russian Artic Eastern Section

Science.gov (United States)

Golobokova, Liudmila; Polkin, Victor

2014-05-01

The newly observed kickoff of the Northern Route development drew serious attention to state of the Arctic Resource environment. Occurring climatic and environmental changes are more sensitively seen in polar areas in particular. Air environment control allows for making prognostic assessments which are required for planning hazardous environmental impacts preventive actions. In August - September 2013, RV «Professor Khlustin» Northern Sea Route expeditionary voyage took place. En-route aerosol sampling was done over the surface of the Beringov, Chukotka and Eastern-Siberia seas (till the town of Pevek). The purpose of sampling was to assess spatio-temporal variability of optic, microphysical and chemical characteristics of aerosol particles of the surface layer within different areas adjacent to the Northern Sea Route. Aerosol test made use of automated mobile unit consisting of photoelectric particles counter AZ-10, aetalometr MDA-02, aspirator on NBM-1.2 pump chassis, and the impactor. This set of equipment allows for doing measurements of number concentration, dispersed composition of aerosols within sizes d=0.3-10 mkm, mass concentration of submicron sized aerosol, and filter-conveyed aerosols sampling. Filter-conveyed aerosols sampling was done using method accepted by EMEP and EANET monitoring networks. The impactor channel was upgraded to separate particles bigger than 1 mkm in size, and the fine grain fraction settled down on it. Reverse 5-day and 10-day trajectories of air mass transfer executed at heights of 10, 1500 and 3500 m were analyzed. The heights were selected by considerations that 3000 m is the height which characterizes air mass trend in the lower troposphere. 1500 m is the upper border of the atmospheric boundary layer, and the sampling was done in the Earth's surface layer at less than 10 m. Minimum values of the bespoken microphysical characteristics are better characteristic of higher latitudes where there are no man induced sources of

Environmental changes of the last 30,000 years in the gas hydrate area of Joetsu Basin, eastern margin of Japan Sea

Energy Technology Data Exchange (ETDEWEB)

Freire, A.F.M.; Sugai, T. [Tokyo Univ., Kashiwanoha Campus, Chiba (Japan). Dept. of Natural Environmental Studies; Takeuchi, E.; Nagasaka, A.; Hiruta, A.; Ishizaki, O.; Matsumoto, R. [Tokyo Univ., Hongo Campus, Bunkyo-ku, Tokyo (Japan). Dept. of Earth and Planetary Science

2008-07-01

The Japan Sea is a semi-isolated marginal sea with an average depth of 1350 metres and a maximum water depth of approximately 3700 metres in the northern basin. This paper presented a study that inferred the age and the nature of the environmental events of the last 30 thousand years using geochemical and sedimentary records from piston cores collected on the gas hydrates bearing-sediments of Joetsu Basin, eastern margin of Japan Sea, south of Sado Islands. Interbedded dark gray thinly laminates and dark brown to gray bioturbated units are common throughout the quaternary sediments of the Japan Sea. They have been explained in terms of glacio-eustatic sea-level change. Active methane venting and gas hydrates have also been recognized, which are widely distributed just beneath the sea floor in the Joetsu Basin, in the eastern margin of the Japan Sea. In order to identify the nature of the organic matter present in the study area and to make a correlation with samples collected in the Pacific Ocean, the study utilized total organic carbon contents and carbon isotopic composition of the gas hydrates bearing-sediments. Using X-ray diffraction analysis, these data were used to apply sequence stratigraphy concepts to locate the holocene/pleistocene boundary and to identify key stratigraphic surfaces, and also to recognize methane flux variations and sulfate-methane interfaces. The paper discussed total organic carbon in the Holocene/Pleistocene boundaries; nature of the organic matter and terrestrial versus marine phytoplankton production; and terrigenous material input. Sulfate oxidation of methane was also discussed. It was concluded that the correlation between the Japan Sea and Pacific Ocean was possible using piston cores. 13 refs., 13 figs.

Temporal and spatial variations in provenance of Eastern Mediterranean Sea sediments: Implications for Aegean and Aeolian arc volcanism

NARCIS (Netherlands)

Klaver, M.; Djuly, T.; de Graaf, S.; Sakes, A.; Wijbrans, J.R.; Davies, G.R.; Vroon, P.Z.

2015-01-01

The Eastern Mediterranean Sea (EMS) is the last remnant of the Tethys Ocean that has been subducted to the north since the Jurassic. Subduction has led to the formation of multiple island arcs in the EMS region where the Aeolian and Aegean arcs are currently active. The EMS is surrounded by

Vertical distributions and speciation of dissolved rare earth elements in the anoxic brines of Bannock Basin, eastern Mediterranean Sea

NARCIS (Netherlands)

Schijf, Johan; Baar, Hein J.W. de; Millero, Frank J.; Byrne, R.H.

1995-01-01

Vertical distributions of dissolved rare earth elements (REEs) are presented for the anoxic, highly sulfidic brines of Bannock Basin in the eastern Mediterranean Sea. REE concentrations at the seawater-brine interface are the highest ever recorded in the water column of an anoxic basin and

Polynya dynamics and associated atmospheric forcing at the Ronne Ice Shelf

Science.gov (United States)

Ebner, Lars; Heinemann, Günther

2014-05-01

The Ronne Ice Shelf is known as one of the most active regions of polynya developments around the Antarctic continent. Low temperatures are prevailing throughout the whole year, particularly in winter. It is generally recognized that polynya formations are primarily forced by offshore winds and secondarily by ocean currents. Many authors have addressed this issue previously at the Ross Ice Shelf and Adélie Coast and connected polynya dynamics to strong katabatic surge events. Such investigations of atmospheric dynamics and simultaneous polynya occurrence are still severely underrepresented for the southwestern part of the Weddell Sea and especially for the Ronne Ice Shelf. Due to the very flat terrain gradients of the ice shelf katabatic winds are of minor importance in that area. Other atmospheric processes must therefore play a crucial role for polynya developments at the Ronne Ice Shelf. High-resolution simulations have been carried out for the Weddell Sea region using the non-hydrostatic NWP model COSMO from the German Meteorological Service (DWD). For the austral autumn and winter (March to August) 2008 daily forecast simulations were conducted with the consideration of daily sea-ice coverage deduced from the passive microwave system AMSR-E. These simulations are used to analyze the synoptic and mesoscale atmospheric dynamics of the Weddell Sea region and find linkages to polynya occurrence at the Ronne Ice Shelf. For that reason, the relation between the surface wind speed, the synoptic pressure gradient in the free atmosphere and polynya area is investigated. Seven significant polynya events are identified for the simulation period, three in the autumn and four in the winter season. It can be shown that in almost all cases synoptic cyclones are the primary polynya forcing systems. In most cases the timely interaction of several passing cyclones in the northern and central Weddell Sea leads to maintenance of a strong synoptic pressure gradient above the

Coupled wave and surge modelling for the eastern Irish Sea and implications for model wind-stress

Science.gov (United States)

Brown, Jennifer M.; Wolf, Judith

2009-05-01

We revisit the surge of November 1977, a storm event which caused damage on the Sefton coast in NW England. A hindcast has been made with a coupled surge-tide-wave model, to investigate whether a wave-dependent surface drag is necessary for accurate surge prediction, and also if this can be represented by an optimised Charnock parameter. The Proudman Oceanographic Laboratory Coastal Modelling System-Wave Model (POLCOMS-WAM) has been used to model combined tides, surges, waves and wave-current interaction in the Irish Sea on a 1.85 km grid. This period has been previously thoroughly studied, e.g. Jones and Davies [Jones, J.E., Davies, A.M., 1998. Storm surge computations for the Irish Sea using a three-dimensional numerical model including wave-current interaction. Continental Shelf Research 18(2), 201-251] and we build upon this previous work to validate the POLCOMS-WAM model to test the accuracy of surge elevation predictions in the study area. A one-way nested approach has been set up from larger scale models to the Irish Sea model. It was demonstrated that (as expected) swell from the North Atlantic does not have a significant impact in the eastern Irish Sea. To capture the external surge generated outside of the Irish Sea a (1/9° by 1/6°) model extending beyond the continental shelf edge was run using the POLCOMS model for tide and surge. The model results were compared with tide gauge observations around the eastern Irish Sea. The model was tested with different wind-stress formulations including Smith and Banke [Smith, S.D., Banke, E.G., 1975. Variation of the surface drag coefficient with wind speed. Quarterly Journal of the Royal Meteorology Society, 101(429), 665-673] and Charnock [Charnock, H., 1955. Wind-stress on a water surface. Quarterly Journal of the Royal Meteorological Society, 81(350), 639-640]. In order to get a single parameterisation that works with wave-coupling, the wave-derived surface roughness length has been imposed in the surge model

A glimpse beneath Antarctic sea ice: observation of platelet-layer thickness and ice-volume fraction with multifrequency EM

Science.gov (United States)

Hoppmann, Mario; Hunkeler, Priska A.; Hendricks, Stefan; Kalscheuer, Thomas; Gerdes, Rüdiger

2016-04-01

In Antarctica, ice crystals (platelets) form and grow in supercooled waters below ice shelves. These platelets rise, accumulate beneath nearby sea ice, and subsequently form a several meter thick, porous sub-ice platelet layer. This special ice type is a unique habitat, influences sea-ice mass and energy balance, and its volume can be interpreted as an indicator of the health of an ice shelf. Although progress has been made in determining and understanding its spatio-temporal variability based on point measurements, an investigation of this phenomenon on a larger scale remains a challenge due to logistical constraints and a lack of suitable methodology. In the present study, we applied a lateral constrained Marquardt-Levenberg inversion to a unique multi-frequency electromagnetic (EM) induction sounding dataset obtained on the ice-shelf influenced fast-ice regime of Atka Bay, eastern Weddell Sea. We adapted the inversion algorithm to incorporate a sensor specific signal bias, and confirmed the reliability of the algorithm by performing a sensitivity study using synthetic data. We inverted the field data for sea-ice and platelet-layer thickness and electrical conductivity, and calculated ice-volume fractions within the platelet layer using Archie's Law. The thickness results agreed well with drillhole validation datasets within the uncertainty range, and the ice-volume fraction yielded results comparable to other studies. Both parameters together enable an estimation of the total ice volume within the platelet layer, which was found to be comparable to the volume of landfast sea ice in this region, and corresponded to more than a quarter of the annual basal melt volume of the nearby Ekström Ice Shelf. Our findings show that multi-frequency EM induction sounding is a suitable approach to efficiently map sea-ice and platelet-layer properties, with important implications for research into ocean/ice-shelf/sea-ice interactions. However, a successful application of this

Submarine canyons as coral and sponge habitat on the eastern Bering Sea slope

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Robert J. Miller

2015-07-01

Full Text Available Submarine canyons have been shown to positively influence pelagic and benthic biodiversity and ecosystem function. In the eastern Bering Sea, several immense canyons lie under the highly productive “green belt” along the continental slope. Two of these, Pribilof and Zhemchug canyons, are the focus of current conservation interest. We used a maximum entropy modeling approach to evaluate the importance of these two canyons, as well as canyons in general, as habitat for gorgonian (alcyonacean corals, pennatulacean corals, and sponges, in an area comprising most of the eastern Bering Sea slope and outer shelf. These invertebrates create physical structure that is a preferred habitat for many mobile species, including commercially important fish and invertebrates. We show that Pribilof canyon is a hotspot of structure-forming invertebrate habitat, containing over 50% of estimated high-quality gorgonian habitat and 45% of sponge habitat, despite making up only 1.7% of the total study area. The amount of quality habitat for gorgonians and sponges varied in other canyons, but canyons overall contained more high-quality habitat for structure-forming invertebrates compared to other slope areas. Bottom trawling effort was not well correlated with habitat quality for structure-forming invertebrates, and bottom-contact fishing effort in general, including longlining and trawling, was not particularly concentrated in the canyons examined. These results suggest that if conserving gorgonian coral habitat is a management goal, canyons, particularly Pribilof Canyon, may be a prime location to do this without excessive impact on fisheries.

Recently studied sedimentary records from the eastern Arabian Sea: Implications to Holocene monsoonal variability

Digital Repository Service at National Institute of Oceanography (India)

Agnihotri, R.; Kurian, S.

stream_size 72460 stream_content_type text/plain stream_name Earth_Sci_India_1_258.pdf.txt stream_source_info Earth_Sci_India_1_258.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8 Agnihotri http://www....earthscienceindia.info/Agnihotri.htm 1 of 14 10/15/2008 9:41 AM Earth Science India Vol.1 (IV), October, 2008, pp. 258-287 http://www.earthscienceindia.info/ Recently studied sedimentary records from the eastern Arabian Sea: Implications to Holocene monsoonal variability Rajesh...

An illustrated catalogue of Rudolf Sturany’s type specimens in the Naturhistorisches Museum Wien, Austria (NHMW: deep-sea Eastern Mediterranean molluscs

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Paolo G. Albano

2018-01-01

Full Text Available The “Pola” expeditions were the first to explore the deep Eastern Mediterranean Sea in the 1890s. They remained the most intense surveys in that area for a century and constitute today a fundamental baseline to assess change in the basin, whose fauna is still inadequately described. Solid taxonomic foundations for the study of deep-sea organisms are needed and we here contribute by revising the name-bearing types of mollusc species introduced by Rudolf Sturany on the basis of the “Pola” material from the Eastern Mediterranean Sea stored in the Natural History Museum in Vienna. Sturany introduced 15 names (Marginella occulta var. minor Sturany, 1896 shall not be considered as the introduction of a new name. He described and established two manuscript names by Monterosato: Jujubinus igneus and Pseudomurex ruderatus. The genus Isorropodon was also introduced together with its type species I. perplexum. For each name, we list the available type material, provide the original description and a translation into English and illustrate the specimens in colour and with SEM imaging.

Integrated survey of elemental stoichiometry (C, N, P from the western to eastern Mediterranean Sea

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M. Pujo-Pay

2011-04-01

Full Text Available This paper provides an extensive vertical and longitudinal description of the biogeochemistry along an East-West transect of 3000 km across the Mediterranean Sea during summer 2008 (BOUM cruise. During this period of strong stratification, the distribution of nutrients, particulate and dissolved organic carbon (DOC, nitrogen (DON and phosphorus (DOP were examined to produce a detailed spatial and vertically extended description of the elemental stoichiometry of the Mediterranean Sea. Surface waters were depleted in nutrients and the thickness of this depleted layer increased towards the East from about 10 m in the Gulf of Lion to more than 100 m in the Levantine basin, with the phosphacline deepening to a greater extent than that for corresponding nitracline and thermocline depths. We used the minimum oxygen concentration through the water column in combination with 2 fixed concentrations of dissolved oxygen to distinguish an intermediate layer (Mineralization Layer; ML from surface (Biogenic Layer; BL, and deep layers (DL. Whilst each layer was represented by different water masses, this approach allowed us to propose a schematic box-plot representation of the biogeochemical functioning of the two Mediterranean basins. Despite the increasing oligotrophic nature and the degree of P-depletion along the West to East gradient strong similarities were encountered between eastern and western ecosystems. Within the BL, the C:N:P ratios in all pools largely exceeded the Redfield ratios, but surprisingly, the nitrate vs. phosphate ratios in the ML and DL tended towards the canonical Redfield values in both basins. A change in particulate matter composition has been identified by a C increase relative to N and P along the whole water column in the western basin and between BL and ML in the eastern one. Our data showed a noticeable stability of the DOC:DON ratio (12–13 throughout the Mediterranean Sea. This is in good agreement with a P-limitation of

The diet and feeding ecology of Conger conger (L. 1758 in the deep waters of the Eastern Ionian Sea

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A. ANASTASOPOULOU

2013-06-01

Full Text Available The diet of the European conger eel Conger conger was investigated for the first time in the Eastern Mediterranean. Fish dominated the European conger eel diet in the deep waters of E. Ionian Sea. All other prey taxa were identified as accidental preys. However, intestine analysis showed that Natantia, Brachyura and Cephalopoda might have a more important contribution in the diet of the species. C. conger exhibited a benthopelagic feeding behavior as it preyed upon both demersal and mesopelagic taxa. The high vacuity index and the low stomach and intestine fullness indicated that the feeding intensity of the species in the deep waters of Eastern Ionian Sea was quite low. C. conger feeding strategy was characterised by specialisation in various resource items. A between-phenotype contribution to niche width was observed for some prey categories. European Conger eel feeding specialisation seemed to be an adaptation to a food-scarce environment, as typified in deep-water habitats

Heat loss in air of an Antarctic marine mammal, the Weddell seal.

Science.gov (United States)

Mellish, Jo-Ann; Hindle, Allyson; Skinner, John; Horning, Markus

2015-01-01

The conflicting needs of homeostasis in air versus water complicate our understanding of thermoregulation in marine mammals. Large-scale modeling efforts directed at predicting the energetic impact of changing sea ice conditions on polar ecosystems require a better understanding of thermoregulation in air of free-ranging animals. We utilized infrared imaging as an indirect approach to determine surface temperatures of dry, hauled-out Weddell seals (Leptonychotes weddellii, n = 35) of varying age and body condition during the Antarctic summer. The study groups provided a fivefold range in body mass and a threefold range in blubber depth. Surface temperature (T s) did not vary by body region (head, shoulder, axilla, torso, hip, flippers). Average seal T s (mean 13.9 ± 11.2 °C) was best described through a combination of the physical traits of body mass and environmental variables of ambient temperature T air, and wind speed. Additional factors of ice temperature (T ice), relative humidity and cloud cover did not improve the model. Heat transfer model estimates suggested that radiation contributed 56.6 ± 7.7 % of total heat loss. Convection and conduction accounted for the remaining 15.7 ± 12.3 and 27.7 ± 9.3 %, respectively. Heat loss by radiation was primarily influenced by body mass and wind speed, whereas convective heat loss was influenced primarily by blubber depth and wind speed. Conductive heat loss was modeled largely as a function of physical traits of mass and blubber depth rather than any environmental covariates, and therefore was substantially higher in animals in leaner condition.

Climatology of sea breezes along the Red Sea coast of Saudi Arabia

KAUST Repository

Khan, Basit; Abualnaja, Yasser; Al-Subhi, Abdullah M.; Nellayaputhenpeedika, Mohammedali; Nellikkattu Thody, Manoj; Sturman, Andrew P.

2018-01-01

and Atmospheric Administration (NOAA) are used to investigate the climatology of sea breezes over the eastern side of the Red Sea region. Results show existence of separate sea breeze systems along different segments of the Red Sea coastline. Based on the physical

Assessment of MODIS-Aqua chlorophyll-a algorithms in coastal and shelf waters of the eastern Arabian Sea

Science.gov (United States)

Tilstone, Gavin H.; Lotliker, Aneesh A.; Miller, Peter I.; Ashraf, P. Muhamed; Kumar, T. Srinivasa; Suresh, T.; Ragavan, B. R.; Menon, Harilal B.

2013-08-01

The use of ocean colour remote sensing to facilitate the monitoring of phytoplankton biomass in coastal waters is hampered by the high variability in absorption and scattering from substances other than phytoplankton. The eastern Arabian Sea coastal shelf is influenced by river run-off, winter convection and monsoon upwelling. Bio-optical parameters were measured along this coast from March 2009 to June 2011, to characterise the optical water type and validate three Chlorophyll-a (Chla) algorithms applied to Moderate Resolution Imaging Spectroradiometer on Aqua (MODIS-Aqua) data against in situ measurements. Ocean Colour 3 band ratio (OC3M), Garver-Siegel-Maritorena Model (GSM) and Generalized Inherent Optical Property (GIOP) Chla algorithms were evaluated. OC3M performed better than GSM and GIOP in all regions and overall, was within 11% of in situ Chla. GSM was within 24% of in situ Chla and GIOP on average was 55% lower. OC3M was less affected by errors in remote sensing reflectance Rrs(λ) and by spectral variations in absorption coefficient (aCDOM(λ)) of coloured dissolved organic material (CDOM) and total suspended matter (TSM) compared to the other algorithms. A nine year Chla time series from 2002 to 2011 was generated to assess regional differences between OC3M and GSM. This showed that in the north eastern shelf, maximum Chla occurred during the winter monsoon from December to February, where GSM consistently gave higher Chla compared to OC3M. In the south eastern shelf, maximum Chla occurred in June to July during the summer monsoon upwelling, and OC3M yielded higher Chla compared to GSM. OC3M currently provides the most accurate Chla estimates for the eastern Arabian Sea coastal waters.

Wave hindcast studies using SWAN nested in WAVEWATCH III - comparison with measured nearshore buoy data off Karwar, eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Amrutha, M.M.; SanilKumar, V.; Sandhya, K.G.; Nair, T.M.B; Rathod, J.L.

Waves in the nearshore waters (~15 m water-depth) of eastern Arabian Sea were simulated using SWAN nested in WAVEWATCH III (WW3) for the year 2014. The sensitivity of the numerical wave model WW3 towards different source term (ST) packages...

Sequence stratigraphy and a revised sea-level curve for the Middle Devonian of eastern North America

Science.gov (United States)

Brett, Carlton E.; Baird, G.C.; Bartholomew, A.J.; DeSantis, M.K.; Ver Straeten, C.A.

2011-01-01

The well-exposed Middle Devonian rocks of the Appalachian foreland basin (Onondaga Formation; Hamilton Group, Tully Formation, and the Genesee Group of New York State) preserve one of the most detailed records of high-order sea-level oscillation cycles for this time period in the world. Detailed examination of coeval units in distal areas of the Appalachian Basin, as well as portions of the Michigan and Illinois basins, has revealed that the pattern of high-order sea-level oscillations documented in the New York-Pennsylvania section can be positively identified in all areas of eastern North America where coeval units are preserved. The persistence of the pattern of high-order sea-level cycles across such a wide geographic area suggests that these cycles are allocyclic in nature with primary control on deposition being eustatic sea-level oscillation, as opposed to autocylic controls, such as sediment supply, which would be more local in their manifestation. There is strong evidence from studies of cyclicity and spectral analysis that these cycles are also related to Milankovitch orbital variations, with the short and long-term eccentricity cycles (100. kyr and 405. kyr) being the dominant oscillations in many settings. Relative sea-level oscillations of tens of meters are likely and raise considerable issues about the driving mechanism, given that the Middle Devonian appears to record a greenhouse phase of Phanerozoic history. These new correlations lend strong support to a revised high-resolution sea-level oscillation curve for the Middle Devonian for the eastern portion of North America. Recognized third-order sequences are: Eif-1 lower Onondaga Formation, Eif-2: upper Onondaga and Union Springs formations; Eif-Giv: Oatka Creek Formation; Giv-1: Skaneateles, Giv-2: Ludlowville, Giv-3: lower Moscow, Giv-4: upper Moscow-lower Tully, and Giv-5: middle Tully-Geneseo formations. Thus, in contrast with the widely cited eustatic curve of Johnson et al. (1985), which

LATE PLIOCENE-HOLOCENE DEBRIS FLOW DEPOSITS IN THE IONIAN SEA (EASTERN MEDITERRANEAN

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GIOVANNI ALOISI DE LARDEREL

1997-11-01

Full Text Available Widespread coring of the Eastern Mediterranean Basin has outlined the existence of a systematic relation between lithology of debris flow deposits and physiographic setting. Whilst the topographic highs are characterized by pelagic sedimentation, the basin floors are alternatively subject to pelagic sedimentation and re-sedimentation pro cesses. Amongst the latters, turbidity flows and debris flows are the most common transport mechanisms.In this paper we present the study of the debris flow pro cess in the Ionian Sea using visual description of cores, grain size, carbonate content and smear slide analysis carried out on gravity and piston cores recovered over the past 20 years. A distinction has been made between debris flow deposits originating from the continental margins (North Africa and Malta Escarpment and those emplaced in the small basins amidst the Calabrian and Mediterranean ridges "Cobblestone Topography". As a result of the difference in setting, the former debris flow deposits include a great variety of lithologies and ages whilst the latter involve the pelagic sediments forming the typical Eastern Mediterranean Plio-Quaternary succession. A detailed study of clast and matrix structures makes it possible to describe the flows in terms of existing classifications of sediment gravity flows and to assume a clast support mechanism. Finally, biostratigraphy coupled with the presence of widespread marker beds enabled us to estimate the age of emplacement of the deposits and to hypothesize a triggering mechanism for flow initiation. Three flows are strictly related to the pelagic turbidite named homogenite, triggered by the explosive eruption of the Santorini volcano (Minoan eruption and therefore have an estimated age of 3,500 BP. The other deposits have ages ranging from 9,000 BP to about 70,000 BP and were originated by debris flows triggered by events such as earthquakes and glacial low sea level stands.    

AFSC/RACE/EcoFOCI: Chlorophyll: variability in spring chlorophyll concentrations and zooplankotn on the eastern Bering Sea shelf - cruise Healy 07-01

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — These data were collected under NSF Grant # ARC-0722448 ("BEST: Impacts of Sea-ice on the Hydrographic Structure, Nutrients, and Mesozooplankton over the Eastern...

Chemical oceanography of the Arabian Sea: Part III - Studies on nutrient fraction and stoichiometric relationship in the Northern and the Eastern Basins

Digital Repository Service at National Institute of Oceanography (India)

SenGupta, R.; Sankaranarayanan, V.N.; DeSousa, S.N.; Fondekar, S.P.

Phosphorus and inorganic nitrogen compounds have been divided into 'reserved' andoxidative fractions based on their relationships with apparent oxygen utilization in the northern and the north-eastern basins of the Arabian Sea.Two oxygen minima...

Rapid Response of Eastern Mediterranean Deep Sea Microbial Communities to Oil

Energy Technology Data Exchange (ETDEWEB)

Liu, Jiang; Techtmann, Stephen M.; Woo, Hannah L.; Ning, Daliang; Fortney, Julian L.; Hazen, Terry C.

2017-07-18

Deep marine oil spills like the Deepwater Horizon (DWH) in the Gulf of Mexico have the potential to drastically impact marine systems. Crude oil contamination in marine systems remains a concern, especially for countries around the Mediterranean Sea with off shore oil production. The goal of this study was to investigate the response of indigenous microbial communities to crude oil in the deep Eastern Mediterranean Sea (E. Med.) water column and to minimize potential bias associated with storage and shifts in microbial community structure from sample storage. 16S rRNA amplicon sequencing was combined with GeoChip metagenomic analysis to monitor the microbial community changes to the crude oil and dispersant in on-ship microcosms set up immediately after water collection. After 3 days of incubation at 14 °C, the microbial communities from two different water depths: 824 m and 1210 m became dominated by well-known oil degrading bacteria. The archaeal population and the overall microbial community diversity drastically decreased. Similarly, GeoChip metagenomic analysis revealed a tremendous enrichment of genes related to oil biodegradation, which was consistent with the results from the DWH oil spill. These results highlight a rapid microbial adaption to oil contamination in the deep E. Med., and indicate strong oil biodegradation potentia

234Th-based measurements of particle flux in surface water of the Bransfield Strait, western Antarctica

International Nuclear Information System (INIS)

Gulin, S.B.; National Academy of Sciences of Ukraine, Sevastopol, Autonomous Republic of Crimea

2014-01-01

Measurements of particulate and dissolved 234 Th were carried out in March 2002 in the Bransfield Strait located between the Antarctic Peninsula and the South Shetland Islands. The 234 Th/ 238 U disequilibrium found in the upper water column has allowed evaluation of downward particle fluxes across a frontal zone, which divides water masses coming from the Bellingshausen Sea and the Weddell Sea. The highest particle flux has been found in this mixing zone, where it was 3-5 times greater than in the adjacent waters. Total mass fluxes in the upper 150-m water column were estimated as about 2.2 g m -2 day -1 in the eastern part of the Strait and 3.1 g m -2 day -1 in the western area. (author)

Indo-Pacific sea level variability during recent decades

Science.gov (United States)

Yamanaka, G.; Tsujino, H.; Nakano, H.; Urakawa, S. L.; Sakamoto, K.

2016-12-01

Decadal variability of sea level in the Indo-Pacific region is investigated using a historical OGCM simulation. The OGCM driven by the atmospheric forcing removing long-term trends clearly exhibits decadal sea level variability in the Pacific Ocean, which is associated with eastern tropical Pacific thermal anomalies. During the period of 1977-1987, the sea level anomalies are positive in the eastern equatorial Pacific and show deviations from a north-south symmetric distribution, with strongly negative anomalies in the western tropical South Pacific. During the period of 1996-2006, in contrast, the sea level anomalies are negative in the eastern equatorial Pacific and show a nearly north-south symmetric pattern, with positive anomalies in both hemispheres. Concurrently, sea level anomalies in the south-eastern Indian Ocean vary with those in the western tropical Pacific. These sea level variations are closely related to large-scale wind fields. Indo-Pacific sea level distributions are basically determined by wind anomalies over the equatorial region as well as wind stress curl anomalies over the off-equatorial region.

Black Sea aerosols

International Nuclear Information System (INIS)

Hacisalihoglu, G.; Eliyakut, F.; Anwari, M.A.; Ataman, O.Y.; Balkas, T.I.; Tuncel, G.; Olmez, I.

1991-01-01

Shipboard, high volume air particulate samples were collected from the Black Sea atmosphere and analyzed by instrumental neutron activation analysis, atomic absorption spectrophotometry and ion chromatography for about 40 elements and ions. Concentrations of elements in the eastern and western parts of the Black Sea are different at the 95% confidence level, with lower concentrations in the eastern Black Sea. Back-trajectories and concentrations of elements in trajectory groups show that Europe accounts for more than 70% of the anthropogenic elements in the atmosphere. The average sulfate concentration was 7 μg/m 3 , which is comparable with rural sulfate levels in western Europe. Fluxes of elements from the atmosphere to the Black Sea are in good agreement with the results of similar flux calculations for other regions

Studies on the pore water sulfate, chloride and sedimentary methane to understand the sulfate reduction process in the eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Karisiddaiah, S.M.; Borole, D.V.; Rao, B.R.; Paropkari, A.L.; Joao, H; Kocherla, M.; Sarkar, G.P.; Biswas, G.; Kumar, N.

Sediment cores (~5 m length) from ten stations collected in the water depths of 2665-3210 m in the eastern Arabian Sea were studied for pore water sulfate (SO42-), chloride (Cl-) and lighter-hydrocarbons (methane: C1, ethane:C2 and propane: C3...

Water masses, ocean fronts, and the structure of Antarctic seabird communities: putting the eastern Bellingshausen Sea in perspective

Science.gov (United States)

Ribic, Christine A.; Ainley, David G.; Ford, R. Glenn; Fraser, William R.; Tynan, Cynthia T.; Woehler, Eric J.

2015-01-01

Waters off the western Antarctic Peninsula (i.e., the eastern Bellingshausen Sea) are unusually complex owing to the convergence of several major fronts. Determining the relative influence of fronts on occurrence patterns of top-trophic species in that area, therefore, has been challenging. In one of the few ocean-wide seabird data syntheses, in this case for the Southern Ocean, we analyzed ample, previously collected cruise data, Antarctic-wide, to determine seabird species assemblages and quantitative relationships to fronts as a way to provide context to the long-term Palmer LTER and the winter Southern Ocean GLOBEC studies in the eastern Bellingshausen Sea. Fronts investigated during both winter (April–September) and summer (October–March) were the southern boundary of the Antarctic Circumpolar Current (ACC), which separates the High Antarctic from the Low Antarctic water mass, and within which are embedded the marginal ice zone and Antarctic Shelf Break Front; and the Antarctic Polar Front, which separates the Low Antarctic and the Subantarctic water masses. We used clustering to determine species' groupings with water masses, and generalized additive models to relate species' densities, biomass and diversity to distance to respective fronts. Antarctic-wide, in both periods, highest seabird densities and lowest species diversity were found in the High Antarctic water mass. In the eastern Bellingshausen, seabird density in the High Antarctic water mass was lower (as low as half that of winter) than found in other Antarctic regions. During winter, Antarctic-wide, two significant species groups were evident: one dominated by Adélie penguins (Pygoscelis adeliae) (High Antarctic water mass) and the other by petrels and prions (no differentiation among water masses); in eastern Bellingshausen waters during winter, the one significant species group was composed of species from both Antarctic-wide groups. In summer, Antarctic-wide, a High Antarctic group

Maturity and Fecundity of Spiny Dogfish (Squalus acanthias L., 1758) in the Eastern Black Sea

OpenAIRE

DEMİRHAN, Sefa Ayhan; SEYHAN, Kadir

2014-01-01

The maturity and fecundity of Squalus acanthias spiny dogfish sampled from the south-eastern Black Sea were studied. Age and length at 50% maturity were 10.49 years and 87.57 cm for males, and 11.99 years and 102.97 cm for females, respectively. Mean biennial fecundity was 19.4 eggs and 12.9 pups. A linear relationship between fecundities and length was found: Fe = 0.09 x TLp + 2.12 (r = 0.5) for pups and Fo = 0.27 x TLp - 21.59 (r = 0.7) for eggs.

Rapid changes in surface water carbonate chemistry during Antarctic sea ice melt

Science.gov (United States)

Jones, Elizabeth M.; Bakker, Dorothee C. E.; Venables, Hugh J.; Whitehouse, Michael J.; Korb, Rebecca E.; Watson, Andrew J.

2010-11-01

ABSTRACT The effect of sea ice melt on the carbonate chemistry of surface waters in the Weddell-Scotia Confluence, Southern Ocean, was investigated during January 2008. Contrasting concentrations of dissolved inorganic carbon (DIC), total alkalinity (TA) and the fugacity of carbon dioxide (fCO2) were observed in and around the receding sea ice edge. The precipitation of carbonate minerals such as ikaite (CaCO3.6H2O) in sea ice brine has the net effect of decreasing DIC and TA and increasing the fCO2 in the brine. Deficits in DIC up to 12 +/- 3 μmol kg-1 in the marginal ice zone (MIZ) were consistent with the release of DIC-poor brines to surface waters during sea ice melt. Biological utilization of carbon was the dominant processes and accounted for 41 +/- 1 μmol kg-1 of the summer DIC deficit. The data suggest that the combined effects of biological carbon uptake and the precipitation of carbonates created substantial undersaturation in fCO2 of 95 μatm in the MIZ during summer sea ice melt. Further work is required to improve the understanding of ikaite chemistry in Antarctic sea ice and its importance for the sea ice carbon pump.

Spatial characterization of the meltwater field from icebergs in the Weddell Sea.

Science.gov (United States)

Helly, John J; Kaufmann, Ronald S; Vernet, Maria; Stephenson, Gordon R

2011-04-05

We describe the results from a spatial cyberinfrastructure developed to characterize the meltwater field around individual icebergs and integrate the results with regional- and global-scale data. During the course of the cyberinfrastructure development, it became clear that we were also building an integrated sampling planning capability across multidisciplinary teams that provided greater agility in allocating expedition resources resulting in new scientific insights. The cyberinfrastructure-enabled method is a complement to the conventional methods of hydrographic sampling in which the ship provides a static platform on a station-by-station basis. We adapted a sea-floor mapping method to more rapidly characterize the sea surface geophysically and biologically. By jointly analyzing the multisource, continuously sampled biological, chemical, and physical parameters, using Global Positioning System time as the data fusion key, this surface-mapping method enables us to examine the relationship between the meltwater field of the iceberg to the larger-scale marine ecosystem of the Southern Ocean. Through geospatial data fusion, we are able to combine very fine-scale maps of dynamic processes with more synoptic but lower-resolution data from satellite systems. Our results illustrate the importance of spatial cyberinfrastructure in the overall scientific enterprise and identify key interfaces and sources of error that require improved controls for the development of future Earth observing systems as we move into an era of peta- and exascale, data-intensive computing.

The interaction of prehistoric human settlement, sea level change and tectonic uplift of the Coastal Range, eastern Taiwan

Science.gov (United States)

Yang, H.; Chen, W. S.

2017-12-01

The late Cenozoic mountain belt of Taiwan, resulting from the collision between the Eurasian and Philippine Sea plates, is known for its rapid tectonic uplift. As postglacial sea level rose ca. 15,000 yr ago, the eastern coast of Taiwan, due to the rapid tectonic uplift rate, displayed a totally different scenario comparing with most of the coastal plains around the world. At the beginning of postglacial era, the sea level rising rate was greater than the tectonic uplift rate which induced the original piedmont alluvial fan or coastal plain to be overwhelmed by sea water rapidly. Around 13.5 ka, the tectonic uplift rate caught up with the sea level rising and broad wave-cut platform formed. The approximation of tectonic uplift and sea level rising rates was lasting from 13.5 to 5ka, but shoreline progradation may have been enhanced by increased slope erosion which resulted in the alluvial fan forming at the later time of this period. As soon as the eustasy stabilized, the landmass continued to uplift which might have enhanced the river incising and wave erosion rapidly. Therefore the topographic expression along the eastern fringing of Coastal Range forms extended alluvial-fan, stream, and marine terraces and are covered by late Holocene colluvium and marine deposits. 88 archaeological sites were chosen in this study based on surface survey where the archaeological chronology of cultural stage is established primarily through examining pottery series and associated manual excavation. It is interesting that most of the archaeological sites were located on the alluvial fan although the Holocene marine terraces have formed after 5ka. There are no clear evidences to support a shore-oriented settlement, but the abundant alluvial depositional structures observed from the overlaying formation reveals the stream depositional system was still active at this time. If the Neolithic people wanted to come to the "new born" coastal region for the abundant ocean resources, they

Last Interglacial (Eemian) hydrographic conditions in the south-eastern Baltic Sea, NE Europe, based on dinoflagellates and pollen

DEFF Research Database (Denmark)

Head, Martin J.; Seidenkrantz, Marit Solveig Louise Schramm; Janczyk-Kopikowa, Zofia

2005-01-01

of arctic waters. Warm and saline conditions of 15–20 psu or more, at least twice present levels, persisted throughout the early Eemian. A rise in sea level at Licze appears to correlate with a similar event in eastern Denmark, as both coincide with the increase in Corylus (ca. 750 years...... into the interglacial). This sea-level rise might therefore have a basinwide extent, and has been attributed to an opening of the Danish Belts. Whereas dinoflagellate cysts reflect sustained high salinites within the upper water column, a concomitant increase in abundance of the chlorococcalean alga Pediastrum within......A rich organic-walled dinoflagellate cyst and pollen record from the Licze borehole in northern Poland has been used to reconstruct the hydrographic history of the southeastern Baltic Sea during the Eemian Stage (Last Interglacial) of the Upper Pleistocene. Warm and saline waters (ca. 10–15 psu...

Global latitudinal species diversity gradient in deep-sea benthic foraminifera

Science.gov (United States)

Culver, Stephen J.; Buzas, Martin A.

2000-02-01

Global scale patterns of species diversity for modern deep-sea benthic foraminifera, an important component of the bathyal and abyssal meiofauna, are examined using comparable data from five studies in the Atlantic, ranging over 138° of latitude from the Norwegian Sea to the Weddell Sea. We show that a pattern of decreasing diversity with increasing latitude characterises both the North and South Atlantic. This pattern is confirmed for the northern hemisphere by independent data from the west-central North Atlantic and the Arctic basin. Species diversity in the North Atlantic northwards from the equator is variable until a sharp fall in the Norwegian Sea (ca. 65°N). In the South Atlantic species diversity drops from a maximum in latitudes less than 30°S and then decreases slightly from 40 to 70°S. For any given latitude, North Atlantic diversity is generally lower than in the South Atlantic. Both ecological and historical factors related to food supply are invoked to explain the formation and maintenance of the latitudinal gradient of deep-sea benthic foraminiferal species diversity. The gradient formed some 36 million years ago when global climatic cooling led to seasonally fluctuating food supply in higher latitudes.

Biological parameters and feeding behaviour of invasive whelk Rapana venosa Valenciennes, 1846 in the south-eastern Black Sea of Turkey

Directory of Open Access Journals (Sweden)

Hacer Saglam

2014-06-01

Full Text Available Objective: To determine length-weight relationships, growth type and feeding behavior of the benthic predator Rapa whelk at the coast of Camburnu, south-eastern Black Sea. Methods: Rapa whelk was monthly collected by dredge sampling on the south-eastern Black Sea at 20 m depth. The relationships between morphometric parameters of Rapa whelk were described by linear and exponential models. The allometric growth of each variable relative to shell length (SL was calculated from the function Y=aSLb or logY=loga+blogSL. The functional regression b values were tested by t-test at the 0.05 significance level if it was significantly different from isometric growth. The total time spent on feeding either on mussel tissue or live mussels was recorded for each individual under controlled conditions in laboratory. Results: The length-weight relationships showed positive allometric growth and no inter-sex variability. Body size in the male population was significantly higher than in the individuals of the female. All characters in males and females showed a trend towards allometry rather than isometry. While the total time spent feeding increased with increasing prey size the total time that Rapana venosa spent feeding decreased with increasing Rapa whelk size. The total average feeding time needed by Rapa whelks was 160 min. But they took 310 min on live mussels in 27-28 °C in the laboratory conditions. Conclusions: Length and weight relationships, growth type, total time spent feeding of this species were explained in details for this region. It would be useful to sustainable management in the south-eastern Black Sea of Turkey. The results about the feeding behaviour of this species will contribute to the understanding of the role of this species within the ecosystem.

Molecular analyses of gut contents: elucidating the feeding of co-occurring salps in the Lazarev Sea from a different perspective

OpenAIRE

Metfies, Katja; Nicolaus, Anja; Harbou, Lena von; Bathmann, Ulrich; Peeken, Ilka

2014-01-01

The diet of Antarctic salps was elucidated by investigating their gut content using “Automated Ribosomal Intergenic Spacer Analysis” and 454-pyrosequencing. Salp samples were collected during the Lazarev Krill Study in the Western Weddell Sea (summer 2005/06 and 2007/08, fall 2004, and winter 2006). Two salp species, Salpa thompsoni and Ihlea racovitzai, both occur in the Southern Ocean, can overlap geographically and seasonally. Here we provide evidence that despite the non-selective feeding...

Winter sea ice export from the Laptev Sea preconditions the local summer sea ice cover and fast ice decay

Directory of Open Access Journals (Sweden)

P. Itkin

2017-10-01

Full Text Available Ice retreat in the eastern Eurasian Arctic is a consequence of atmospheric and oceanic processes and regional feedback mechanisms acting on the ice cover, both in winter and summer. A correct representation of these processes in numerical models is important, since it will improve predictions of sea ice anomalies along the Northeast Passage and beyond. In this study, we highlight the importance of winter ice dynamics for local summer sea ice anomalies in thickness, volume and extent. By means of airborne sea ice thickness surveys made over pack ice areas in the south-eastern Laptev Sea, we show that years of offshore-directed sea ice transport have a thinning effect on the late-winter sea ice cover. To confirm the preconditioning effect of enhanced offshore advection in late winter on the summer sea ice cover, we perform a sensitivity study using a numerical model. Results verify that the preconditioning effect plays a bigger role for the regional ice extent. Furthermore, they indicate an increase in volume export from the Laptev Sea as a consequence of enhanced offshore advection, which has far-reaching consequences for the entire Arctic sea ice mass balance. Moreover we show that ice dynamics in winter not only preconditions local summer ice extent, but also accelerate fast-ice decay.

Barium as a productivity proxy in continental margin sediments: A study from the eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

PrakashBabu, C.; Brumsack, H.-J.; Schnetger, B.; Boettcher, M.E.

that Ba is almost entirely involved in the deep regeneration cycle like the nutrient silica (Chan et al., 1977). The accumulation of both Ba and opal implies the possibility of barite formation in microenviron- ments of decaying remains of siliceous....M.A., Pant, A., Sawant, S., Gauns, M., Ma- tondkar, S.G.P., Mohanraju, R., 1996. Phytoplankton pro- duction and chlorophyll distribution in the eastern and cen- tral Arabian Sea in 1994^1995. Curr. Sci. 71, 857^862. Bishop, J.K.B., 1988. The barite-opal...

Chemical immobilization of adult female Weddell seals with tiletamine and zolazepam: effects of age, condition and stage of lactation

Directory of Open Access Journals (Sweden)

Harcourt Robert G

2006-02-01

Full Text Available Abstract Background Chemical immobilization of Weddell seals (Leptonychotes weddellii has previously been, for the most part, problematic and this has been mainly attributed to the type of immobilizing agent used. In addition to individual sensitivity, physiological status may play an important role. We investigated the use of the intravenous administration of a 1:1 mixture of tiletamine and zolazepam (Telazol® to immobilize adult females at different points during a physiologically demanding 5–6 week lactation period. We also compared performance between IV and IM injection of the same mixture. Results The tiletamine:zolazepam mixture administered intravenously was an effective method for immobilization with no fatalities or pronounced apnoeas in 106 procedures; however, there was a 25 % (one animal in four mortality rate with intramuscular administration. Induction time was slightly longer for females at the end of lactation (54.9 ± 2.3 seconds than at post-parturition (48.2 ± 2.9 seconds. In addition, the number of previous captures had a positive effect on induction time. There was no evidence for effects due to age, condition (total body lipid, stage of lactation or number of captures on recovery time. Conclusion We suggest that intravenous administration of tiletamine and zolazepam is an effective and safe immobilizing agent for female Weddell seals. Although individual traits could not explain variation in recovery time, we suggest careful monitoring of recovery times during longitudinal studies (> 2 captures. We show that physiological pressures do not substantially affect response to chemical immobilization with this mixture; however, consideration must be taken for differences that may exist for immobilization of adult males and juveniles. Nevertheless, we recommend a mass-specific dose of 0.50 – 0.65 mg/kg for future procedures with adult female Weddell seals and a starting dose of 0.50 mg/kg for other age classes and other

Contrasting records of sea-level change in the eastern and western North Atlantic during the last 300 years

Science.gov (United States)

Long, A. J.; Barlow, N. L. M.; Gehrels, W. R.; Saher, M. H.; Woodworth, P. L.; Scaife, R. G.; Brain, M. J.; Cahill, N.

2014-02-01

We present a new 300-year sea-level reconstruction from a salt marsh on the Isle of Wight (central English Channel, UK) that we compare to other salt-marsh and long tide-gauge records to examine spatial and temporal variability in sea-level change in the North Atlantic. Our new reconstruction identifies an overall rise in relative sea level (RSL) of c. 0.30 m since the start of the eighteenth century at a rate of 0.9±0.3 mm yr. Error-in-variables changepoint analysis indicates that there is no statistically significant deviation from a constant rate within the dataset. The reconstruction is broadly comparable to other tide-gauge and salt-marsh records from the European Atlantic, demonstrating coherence in sea level in this region over the last 150-300 years. In contrast, we identify significant differences in the rate and timing of RSL with records from the east coast of North America. The absence of a strong late 19th/early 20th century RSL acceleration contrasts with that recorded in salt marsh sediments along the eastern USA coastline, in particular in a well-dated and precise sea-level reconstruction from North Carolina. This suggests that this part of the North Carolina sea level record represents a regionally specific sea level acceleration. This is significant because the North Carolina record has been used as if it were globally representative within semi-empirical parameterisations of past and future sea-level change. We conclude that regional-scale differences of sea-level change highlight the value of using several, regionally representative RSL records when calibrating and testing semi-empirical models of sea level against palaeo-records. This is because by using records that potentially over-estimate sea-level rise in the past such models risk over-estimating sea-level rise in the future.

Impacts of the north and tropical Atlantic Ocean on the Antarctic Peninsula and sea ice.

Science.gov (United States)

Li, Xichen; Holland, David M; Gerber, Edwin P; Yoo, Changhyun

2014-01-23

In recent decades, Antarctica has experienced pronounced climate changes. The Antarctic Peninsula exhibited the strongest warming of any region on the planet, causing rapid changes in land ice. Additionally, in contrast to the sea-ice decline over the Arctic, Antarctic sea ice has not declined, but has instead undergone a perplexing redistribution. Antarctic climate is influenced by, among other factors, changes in radiative forcing and remote Pacific climate variability, but none explains the observed Antarctic Peninsula warming or the sea-ice redistribution in austral winter. However, in the north and tropical Atlantic Ocean, the Atlantic Multidecadal Oscillation (a leading mode of sea surface temperature variability) has been overlooked in this context. Here we show that sea surface warming related to the Atlantic Multidecadal Oscillation reduces the surface pressure in the Amundsen Sea and contributes to the observed dipole-like sea-ice redistribution between the Ross and Amundsen-Bellingshausen-Weddell seas and to the Antarctic Peninsula warming. Support for these findings comes from analysis of observational and reanalysis data, and independently from both comprehensive and idealized atmospheric model simulations. We suggest that the north and tropical Atlantic is important for projections of future climate change in Antarctica, and has the potential to affect the global thermohaline circulation and sea-level change.

New data on Eimeria dicentrarchi (Apicomplexa: Eimeriidae), a common parasite of farmed European sea bass (Dicentrarchus labrax) from the mid-eastern Adriatic

Science.gov (United States)

This study extends the original description of Eimeria dicentrarchi Daoudi and Marquès, 1987, a common coccidian parasite of European sea bass from the mid-eastern Adriatic, by providing insights into the parasite’s site of infection, development and pathogenicity. E. dicentrarchi was found in vario...

Decapod crustaceans on the Gökçeada (Imbros island continental shelf (north-eastern Aegean Sea

Directory of Open Access Journals (Sweden)

A.S. ATES

2006-12-01

Full Text Available The present composition of decapod crustaceans found at the sublittoral depths (5-104 m off the coast of the island of Gökçeada (north-eastern Aegean Sea is presented. A total of 28 species (11 caridean shrimps, 1 thalassinid ghost crab, 7 anomurans and 9 brachyuran crabs and 277 specimens were recorded. The caridean shrimp, Athanas nitescens had the highest abundance with a dominance value of 20.94% in samples. The dominant group is caridean, represented by a total of 11 species and an occurrence frequency of 39.29%.

Changes in Sea Salt Emissions Enhance ENSO Variability

Energy Technology Data Exchange (ETDEWEB)

Yang, Yang; Russell, Lynn M.; Lou, Sijia; Lamjiri, Maryam A.; Liu, Ying; Singh, Balwinder; Ghan, Steven J.

2016-11-15

Two 150-year pre-industrial simulations with and without interactive sea salt emissions from the Community Earth System Model (CESM) are performed to quantify the interactions between sea salt emissions and El Niño–Southern Oscillation (ENSO). Variations in sea salt emissions over the tropical Pacific Ocean are affected by changing wind speed associated with ENSO variability. ENSO-induced interannual variations in sea salt emissions result in decreasing (increasing) aerosol optical depth (AOD) by 0.03 over the equatorial central-eastern (western) Pacific Ocean during El Niño events compared to those during La Niña events. These changes in AOD further increase (decrease) radiative fluxes into the atmosphere by +0.2 W m^-2 (-0.4 W m^-2) over the tropical eastern (western) Pacific. Thereby, sea surface temperature increases (decreases) by 0.2–0.4 K over the tropical eastern (western) Pacific Ocean during El Niño compared to La Niña events and enhances ENSO variability by 10%. The increase in ENSO amplitude is a result of systematic heating (cooling) during the warm (cold) phase, of ENSO in the eastern Pacific. Interannual variations in sea salt emissions then produce the anomalous ascent (subsidence) over the equatorial eastern (western) Pacific between El Niño and La Niña events, which is a result of heating anomalies. Due to variations in sea salt emissions, the convective precipitation is enhanced by 0.6–1.2 mm day^-1 over the tropical central-eastern Pacific Ocean and weakened by 0.9–1.5 mm day^-1 over the Maritime Continent during El Niño compared to La Niña events, enhancing the precipitation variability over the tropical Pacific.

AFSC/RACE/FBEP/Hurst: Distributional patterns of 0-group Pacific cod (Gadus macrocephalus) in the eastern Bering Sea under variable recruitment and thermal conditions

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is from a study that analyzed the late summer distribution of juvenile Pacific cod in the eastern Bering Sea for 6 cohorts (2004-2009), based on catches...

Sedimentology and geochemistry of mud volcanoes in the Anaximander Mountain Region from the Eastern Mediterranean Sea.

Science.gov (United States)

Talas, Ezgi; Duman, Muhammet; Küçüksezgin, Filiz; Brennan, Michael L; Raineault, Nicole A

2015-06-15

Investigations carried out on surface sediments collected from the Anaximander mud volcanoes in the Eastern Mediterranean Sea to determine sedimentary and geochemical properties. The sediment grain size distribution and geochemical contents were determined by grain size analysis, organic carbon, carbonate contents and element analysis. The results of element contents were compared to background levels of Earth's crust. The factors that affect element distribution in sediments were calculated by the nine push core samples taken from the surface of mud volcanoes by the E/V Nautilus. The grain size of the samples varies from sand to sandy silt. Enrichment and Contamination factor analysis showed that these analyses can also be used to evaluate of deep sea environmental and source parameters. It is concluded that the biological and cold seep effects are the main drivers of surface sediment characteristics from the Anaximander mud volcanoes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Social Context Predicts Vocalization Use in the Courtship Behaviors of Weddell Seals (Leptonychotes weddellii: A Case Study

Directory of Open Access Journals (Sweden)

Ludivine R. Russell

2016-05-01

Full Text Available Despite previous research, no study has convincingly demonstrated what role if any vocalizations might play in the reproductive behavior of Weddell seals (Leptonychotes weddellii. To better understand that role, we created an artificial territory for an adult, male Weddell seal under the shore-fast ice in McMurdo Sound, Antarctica, and recorded its in situ vocalizations and non-vocal behaviors with an underwater video camera and hydrophone while alone, with another male, and with one or more females. Additionally, we simultaneously recorded the vocalizations and non-vocal behaviors from a female interacting with the male. Analysis of 86 hr of video and audio recordings showed: 1 the male vocalized more than the female, 2 the male’s vocal repertoire was larger than the females’ repertoire, 3 vocalizations changed quantitatively and qualitatively with social context, and 4 patterns of vocalizations and non-vocal behaviors were detected with Theme, pattern recognition software from Noldus Information Technology. These results provided strong evidence that vocalizations played an important role during courtship, and together with the significant behavioral sequences, vocal and non-vocal, they provided insight into the function of their vocalizations including chirps, growls, jaw claps, knocks, mews, trills, and trills + knocks.

Small river plumes near the north-eastern coast of the Black Sea under climatic mean and flooding discharge conditions

Science.gov (United States)

Osadchiev, Alexander; Korshenko, Evgeniya

2017-04-01

The study is focused on the impact of discharge from small rivers on propagation and final location of fluvial waters and suspended matter at the north-eastern part of the Black Sea under different local precipitation conditions. Several dozens of mountainous rivers inflow into the sea at the studied region and most of them, except the several largest of them, have small annual runoff and limitedly affect adjacent coastal waters under climatic mean conditions. However, discharges of these small rivers are characterized by quick response to precipitation events and can dramatically increase during and shortly after heavy rains, which are frequent in the area under consideration. Propagation and final location of fluvial waters and terrigenous sediments at the studied region under climatic mean and rain-induced flooding conditions were explored and compared using in situ data, satellite imagery and numerical modelling. It was shown that the point-source spread of continental discharge dominated by several large rivers during climatic mean conditions can change to the line-source discharge from numerous small rivers situated along the coast in response to heavy rains. Intense line-source runoff of water and suspended sediments form a geostrophic alongshore current of turbid and freshened water, which induces intense transport of suspended and dissolved constituents discharged with river waters in a north-western direction. This process significantly influences water quality and causes active sediment load at large segments of narrow shelf at the north-eastern part of the Black Sea as compared to climatic mean discharge conditions.

Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment

KAUST Repository

Tsiola, A.

2015-12-01

The growth rates of planktonic microbes in the pelagic zone of the Eastern Mediterranean Sea are nutrient limited, but the type of limitation is still uncertain. During this study, we investigated the occurrence of N and P limitation among different groups of the prokaryotic and eukaryotic (pico-, nano-, and micro-) plankton using a microcosm experiment during stratified water column conditions in the Cretan Sea (Eastern Mediterranean). Microcosms were enriched with N and P (either solely or simultaneously), and the PO4 turnover time, prokaryotic heterotrophic activity, primary production, and the abundance of the different microbial components were measured. Flow cytometric and molecular fingerprint analyses showed that different heterotrophic prokaryotic groups were limited by different nutrients; total heterotrophic prokaryotic growth was limited by P, but only when both N and P were added, changes in community structure and cell size were detected. Phytoplankton were N and P co-limited, with autotrophic pico-eukaryotes being the exception as they increased even when only P was added after a 2-day time lag. The populations of Synechococcus and Prochlorococcus were highly competitive with each other; Prochlorococcus abundance increased during the first 2 days of P addition but kept increasing only when both N and P were added, whereas Synechococcus exhibited higher pigment content and increased in abundance 3 days after simultaneous N and P additions. Dinoflagellates also showed opportunistic behavior at simultaneous N and P additions, in contrast to diatoms and coccolithophores, which diminished in all incubations. High DNA content viruses, selective grazing, and the exhaustion of N sources probably controlled the populations of diatoms and coccolithophores.

Formation of Barents Sea Branch Water in the north-eastern Barents Sea

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Vidar S. Lien

2013-09-01

Full Text Available The Barents Sea throughflow accounts for approximately half of the Atlantic Water advection to the Arctic Ocean, while the other half flows through Fram Strait. Within the Barents Sea, the Atlantic Water undergoes considerable modifications before entering the Arctic Ocean through the St. Anna Trough. While the inflow area in the south-western Barents Sea is regularly monitored, oceanographic data from the outflow area to the north-east are very scarce. Here, we use conductivity, temperature and depth data from August/September 2008 to describe in detail the water masses present in the downstream area of the Barents Sea, their spatial distribution and transformations. Both Cold Deep Water, formed locally through winter convection and ice-freezing processes, and Atlantic Water, modified mainly through atmospheric cooling, contribute directly to the Barents Sea Branch Water. As a consequence, it consists of a dense core characterized by a temperature and salinity maximum associated with the Atlantic Water, in addition to the colder, less saline and less dense core commonly referred to as the Barents Sea Branch Water core. The denser core likely constitutes a substantial part of the total flow, and it is more saline and considerably denser than the Fram Strait branch as observed within the St. Anna Trough. Despite the recent warming of the Barents Sea, the Barents Sea Branch Water is denser than observed in the 1990s, and the bottom water observed in the St. Anna Trough matches the potential density at 2000 m depth in the Arctic Ocean.

Sea-Floor geology and character of Eastern Rhode Island Sound West of Gay Head, Massachusetts

Science.gov (United States)

Poppe, L.J.; McMullen, K.Y.; Ackerman, S.D.; Blackwood, D.S.; Irwin, B.J.; Schaer, J.D.; Forrest, M.R.

2011-01-01

Gridded multibeam bathymetry covers approximately 102 square kilometers of sea floor in eastern Rhode Island Sound west of Gay Head, Massachusetts. Although originally collected for charting purposes during National Oceanic and Atmospheric Administration hydrographic survey H11922, these acoustic data and the sea-floor stations subsequently occupied to verify them (1) show the composition and terrain of the seabed, (2) provide information on sediment transport and benthic habitat, and (3) are part of an expanding series of studies that provide a fundamental framework for research and management activities (for example, windfarms and fisheries) along the Massachusetts inner continental shelf. Most of the sea floor in the study area has an undulating to faintly rippled appearance and is composed of bioturbated muddy sand, reflecting processes associated with sediment sorting and reworking. Shallower areas are composed of rippled sand and, where small fields of megaripples are present, indicate sedimentary environments characterized by processes associated with coarse bedload transport. Boulders and gravel were found on the floors of scour depressions and on top of an isolated bathymetric high where erosion has removed the Holocene marine sediments and exposed the underlying relict lag deposits of Pleistocene drift. The numerous scour depressions, which formed during storm-driven events, result in the juxtaposition of sea-floor areas with contrasting sedimentary environments and distinct gravel, sand, and muddy sand textures. This textural heterogeneity in turn creates a complex patchwork of habitats. Our observations of local variations in community structure suggest that this small-scale textural heterogeneity adds dramatically to the sound-wide benthic biological diversity.

Distinct genetic differentiation and species diversification within two marine nematodes with different habitat preference in Antarctic sediments.

Science.gov (United States)

Hauquier, Freija; Leliaert, Frederik; Rigaux, Annelien; Derycke, Sofie; Vanreusel, Ann

2017-05-30

Dispersal ability, population genetic structure and species divergence in marine nematodes are still poorly understood, especially in remote areas such as the Southern Ocean. We investigated genetic differentiation of species and populations of the free-living endobenthic nematode genera Sabatieria and Desmodora using nuclear 18S rDNA, internal transcribed spacer (ITS) rDNA, and mitochondrial cytochrome oxidase I (COI) gene sequences. Specimens were collected at continental shelf depths (200-500 m) near the Antarctic Peninsula, Scotia Arc and eastern side of the Weddell Sea. The two nematode genera co-occurred at all sampled locations, but with different vertical distribution in the sediment. A combination of phylogenetic (GMYC, Bayesian Inference, Maximum Likelihood) and population genetic (AMOVA) analyses were used for species delimitation and assessment of gene flow between sampling locations. Sequence analyses resulted in the delimitation of four divergent species lineages in Sabatieria, two of which could not be discriminated morphologically and most likely constitute cryptic species. Two species were recognised in Desmodora, one of which showed large intraspecific morphological variation. Both genera comprised species that were restricted to one side of the Weddell Sea and species that were widely spread across it. Population genetic structuring was highly significant and more pronounced in the deeper sediment-dwelling Sabatieria species, which are generally less prone to resuspension and passive dispersal in the water column than surface Desmodora species. Our results indicate that gene flow is restricted at large geographic distance in the Southern Ocean, which casts doubt on the efficiency of the Weddell gyre and Antarctic Circumpolar Current in facilitating circum-Antarctic nematode species distributions. We also show that genetic structuring and cryptic speciation can be very different in nematode species isolated from the same geographic area, but with

Investigation of environmental radioactivity in waste dumping areas of the far eastern seas. JAERI's activities in the 1st Japanese-Korean-Russian joint expedition 1994

International Nuclear Information System (INIS)

Amano, Hikaru; Matsunaga, Takeshi; Yabuuchi, Noriaki.

1996-10-01

Large quantities of radioactive waste have been dumped in the Far Eastern Sea by the former USSR and Russia. In order to survey marine radioactive contamination in the Far Eastern Sea, the first Japanese-Korean-Russian joint expedition was conducted according to the governmental agreement. The joint expedition was conducted at the areas of the Russian radioactive waste dumping site from March 18 1994 to April 6, 1994. JAERI participated in this expedition according to the request from STA Japan, and conducted mainly on-board measurement of marine radioactivities. The results showed that the radionuclides concentrations in seawater and seabed sediment samples from the study site were not different from those in the western North Pacific. This report summarises JAERI's activities in the expedition. Final report by Japanese-Korean-Russian government and IAEA is annexed. (author)

Antarctic Bottom Water temperature changes in the western South Atlantic from 1989 to 2014

Science.gov (United States)

Johnson, Gregory C.; McTaggart, Kristene E.; Wanninkhof, Rik

2014-12-01

Warming of abyssal waters in recent decades contributes to global heat uptake and sea level rise. Repeat oceanographic section data in the western South Atlantic taken mostly in 1989 (1995 across the Scotia Sea), 2005, and 2014 are used to quantify warming in abyssal waters that spread northward through the region from their Antarctic origins in the Weddell Sea. While much of the Scotia Sea warmed between 1995 and 2005, only the southernmost portion, on the north side of the Weddell Gyre, continued to warm between 2005 and 2014. The abyssal Argentine Basin also warmed between 1989 and 2005, but again only the southernmost portion continued to warm between 2005 and 2014, suggesting a slowdown in the inflow of the coldest, densest Antarctic Bottom Waters into the western South Atlantic between 1989 and 2014. In contrast, the abyssal waters of the Brazil Basin warmed both between 1989 and 2005 and between 2005 and 2014, at a rate of about 2 m°C yr-1. This warming is also assessed in terms of the rates of change of heights above the bottom for deep isotherms in each deep basin studied. These results, together with findings from previous studies, suggest the deep warming signal observed in the Weddell Sea after the mid-1970s Weddell Polynya was followed by abyssal warming in the Argentine Basin from the late 1970s through about 2005, then warming in the deep Vema Channel from about 1992 through at least 2010, and warming in the Brazil Basin from 1989 to 2014.

Early-to-middle Holocene sea-level fluctuations, coastal progradation and the Neolithic occupations in Yaojiang valley of southern Hangzhou bay, eastern China

Science.gov (United States)

Liu, Y.; Sun, Q.; Fan, D.; Chen, Z.

2017-12-01

The formation of Holocene coast in eastern China provided material base for the development of Neolithic civilizations. The coastal Yaojiang valley of south Hangzhou bay was one of the examples where the well-known Neolithic Hemudu Culture (HC) of Eastern China initiated. Here, we studied the early-to-middle Holocene environment changes in relation to sea-level fluctuations on the basis of a serial of sediment cores based on a set of new Accelerator Mass Spectrometry radiocarbon (AMS 14C) chronology. The result indicated that relative sea-level rose rapidly in the Yaojiang valley at the early Holocene, reaching its maximum at ca. 8000-7800 cal yr BP and then decelerated at ca. 7800-7500 cal yr BP. The alluvial plain in Yaojiang valley began to form at the foothills first and then grew towards the valley center accompanying with the sea-level stabilization after ca. 7500 cal yr BP. This progressive progradation of alluvial plain would attract the early arrivals of foragers to dwell at the foothills to engaging in rice farming after ca.7000 cal yr BP and starting the epic Hemudu Culture. The HC people then move down to the valley center as more land became available thanks to sediment aggregation and progradation. The rise and development of HC were closely associated with the sea-level induced landscape changes in Yaojiang valley at the early-middle Holocene, and the unstable hydraulic condition in the valley after 5000 cal yr BP could be accountable for the cultural termination.

Comparative Morphometric Analysis of the Smallscaled Scorpionfish, Scorpaena Porcus (Scorpaenidae, Scorpaeniformes, from the Southern Coast of the Crimea and Eastern Part of the Adriatic Sea

Directory of Open Access Journals (Sweden)

Manilo L. G.

2016-12-01

Full Text Available Comparative analysis of morphometric characters of small-scaled scorpionfish from the Black Sea (near the southern coast of the Crimea and from the eastern part of the Adriatic Sea showed significant differences in males and females on thirteen plastic and three meristic characters. These differences may be due to unequal abiotic and biotic habitat conditions, and refer about the geographical variability of the species, indicating the presence of two different populations in the study area.

Inventory, distribution, and origin of aliphatic and polyaromatic hydrocarbons in sea water, the surface microlayer, and the aerosols in the tropical Eastern Atlantic

Energy Technology Data Exchange (ETDEWEB)

Marty, J C; Saliot, A; Tissier, M J

1978-03-20

Hydrocarbons have been analyzed in several samples from ''Midlante'' cruise, Cape Verde islands-Canary islands, in the Eastern tropical Atlantic: subsurface water, sea surface microlayer collected by a metallic screen and aerosols collected by filtration of large air volumes at about 12 m. above the sea surface. Detailed analysis of aliphatic and polyaromatic hydrocarbons has been made by computerized gas chromatography/mass spectrometry. This study of the air/sea interface indicates a discontinuity in hydrocarbon composition between the underlying water and the microlayer and a similarity between the surface microlayer and the aerosols. The origin of the collected aerosols is essentially marine with a minor terrestrial contribution. The hydrocarbon pattern shows that, superimposed on the typical marine components, a contribution from smokes of natural and industrial origin and/or from pollution associated with crude oil sea slicks is present.

Annual Acoustic Presence of Fin Whale (Balaenoptera physalus) Offshore Eastern Sicily, Central Mediterranean Sea

Science.gov (United States)

Sciacca, Virginia; Caruso, Francesco; Beranzoli, Laura; Chierici, Francesco; De Domenico, Emilio; Embriaco, Davide; Favali, Paolo; Giovanetti, Gabriele; Larosa, Giuseppina; Marinaro, Giuditta; Papale, Elena; Pavan, Gianni; Pellegrino, Carmelo; Pulvirenti, Sara; Simeone, Francesco; Viola, Salvatore; Riccobene, Giorgio

2015-01-01

In recent years, an increasing number of surveys have definitively confirmed the seasonal presence of fin whales (Balaenoptera physalus) in highly productive regions of the Mediterranean Sea. Despite this, very little is yet known about the routes that the species seasonally follows within the Mediterranean basin and, particularly, in the Ionian area. The present study assesses for the first time fin whale acoustic presence offshore Eastern Sicily (Ionian Sea), throughout the processing of about 10 months of continuous acoustic monitoring. The recording of fin whale vocalizations was made possible by the cabled deep-sea multidisciplinary observatory, “NEMO-SN1”, deployed 25 km off the Catania harbor at a depth of about 2,100 meters. NEMO-SN1 is an operational node of the European Multidisciplinary Seafloor and water-column Observatory (EMSO) Research Infrastructure. The observatory was equipped with a low-frequency hydrophone (bandwidth: 0.05 Hz–1 kHz, sampling rate: 2 kHz) which continuously acquired data from July 2012 to May 2013. About 7,200 hours of acoustic data were analyzed by means of spectrogram display. Calls with the typical structure and patterns associated to the Mediterranean fin whale population were identified and monitored in the area for the first time. Furthermore, a background noise analysis within the fin whale communication frequency band (17.9–22.5 Hz) was conducted to investigate possible detection-masking effects. The study confirms the hypothesis that fin whales are present in the Ionian Sea throughout all seasons, with peaks in call detection rate during spring and summer months. The analysis also demonstrates that calls were more frequently detected in low background noise conditions. Further analysis will be performed to understand whether observed levels of noise limit the acoustic detection of the fin whales vocalizations, or whether the animals vocalize less in the presence of high background noise. PMID:26581104

Evidence for eddy formation in the eastern Arabian Sea during the northeast monsoon

Science.gov (United States)

Bruce, John G.; Johnson, Donald R.; Kindle, John C.

1994-01-01

The seasonal formation of a large (500-800 km diameter) anticyclonic eddy in the upper 300-400 m of the eastern Arabian Sea during the northest monsoon period (December-April) is indicated fom hydrographic and satellite altimetry sea level observations, as well as from numerical model experiments. The center of the eddy circulation is approximately 10 deg N, 70 deg E, just to the west of the north-south Laccadive Island chain. In this paper the eddy is called the Laccadive High (LH). In some ways it is like a mirrorlike counterpart to the Great Whirl that develops during the southwest monsoon of the Somali coast (western Arabian Sea). The LH occurs at the same latitude but on the opposite side of the basin during the reversed monsoon. It is different from the Great Whirl, however, in its formation process, its intensity, and its decay. The hydrographic data obtained from surveys all during a single season give sufficiently close station spacing to allow reasonable contouring of the geopotential surfaces and of the properties within and around the LH region with minimum time aliasing. The Geostat altimeter record extends over 4 years, during which the seasonal variability of the LH indicates a dynamic relief of approximately 15-20 cm, which is in good agreement with the hydrographics observations. The altimetry time series also suggests a westward translation of the LH by January with a subsequent dissipation in midbasin. The model used is a wind-forced three-layer primitive equation model which depicts a LH agreement with the timing, position, and amplitude of both the hydrographic and altimetric measurements. The numerical simulation includes a passive tracer located in the Western Bay of Bengal; the western advection of the tracer around the south coasts of Sri Lanka and India in December and January is consistent with the appearance of low-salinity water observed to extend into the Arabian Sea during this period. The modeling studies suggest that both local and

Investigation of environmental radioactivity in waste dumping areas of the far eastern seas. JAERI`s activities in the 1st Japanese-Korean-Russian joint expedition 1994

Energy Technology Data Exchange (ETDEWEB)

Amano, Hikaru; Matsunaga, Takeshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yabuuchi, Noriaki

1996-10-01

Large quantities of radioactive waste have been dumped in the Far Eastern Sea by the former USSR and Russia. In order to survey marine radioactive contamination in the Far Eastern Sea, the first Japanese-Korean-Russian joint expedition was conducted according to the governmental agreement. The joint expedition was conducted at the areas of the Russian radioactive waste dumping site from March 18 1994 to April 6, 1994. JAERI participated in this expedition according to the request from STA Japan, and conducted mainly on-board measurement of marine radioactivities. The results showed that the radionuclides concentrations in seawater and seabed sediment samples from the study site were not different from those in the western North Pacific. This report summarises JAERI`s activities in the expedition. Final report by Japanese-Korean-Russian government and IAEA is annexed. (author)

Seasonality of Reproduction and Embryonic Growth of Spiny Dogfish (Squalus acanthias L., 1758) in the Eastern Black Sea

OpenAIRE

DEMİRHAN, Sefa Ayhan; SEYHAN, Kadir

2006-01-01

The seasonality of reproduction and embryonic development of spiny dogfish (Squalus acanthias) sampled from the Eastern Black Sea were studied. The gestation period of spiny dogfish, starting in August, September and October, takes around 23-24 months. Fertilized females were caught at a depth of 30-45 m in July and August. Females with full-term pups and empty uteri were found at 50-60 m depth, where the temperature was 10 °C. Lengths of pups at birth were around 28-29 cm, whereas their weig...

Shifts in Ross Sea food web structure as indicated by δ15N and δ13C values of fossil Antarctic seals

Science.gov (United States)

Leopold, A.; Brault, E.; McMahon, K.

2013-12-01

As climate change continues to mount, there is a growing need for understanding its effects on biological-physical interactions of marine ecosystems. Assessing the effects of anthropogenic activities on the coastal marine ecosystem involves understanding the underlying mechanisms driving these changes as well as establishing baselines of the natural system. Preliminary findings have indicated shifts in bulk carbon (C) and nitrogen (N) isotopic values of southern elephant seal (Mirounga leonina) samples, collected in the Dry Valleys of Antarctica in the Ross Sea region, over approximately the last 7,000 years. These shifts could result from 1) seals changing their foraging location and/or diet over this time, 2) climate change-induced shifts in the biogeochemistry at the base of the food web, or 3) some combination of both processes. We explored the patterns of long-term change in Ross Sea food web structure by examining the stable isotope values of three top predators in this system, Weddell seals (Leptonychotes weddellii), leopard seals (Hydrurga leptonyx), and crabeater seals (Lobodon carcinophagus). Fossil seal samples were collected in the Dry Valleys during the austral summer of 2012/13 and then analyzed for bulk C and N isotopes via an elemental analyzer/isotope-ratio mass spectrometer (EA/IRMS). Our initial findings indicate that C isotopic values of fossil seal samples from Weddell, leopard, and crabeater seals were more enriched than isotopic values of modern seals of the same species (e.g., δ13C = -22.79 × 0.92 ‰ and -26.71 × 0.50 ‰ for fossil and modern crabeater seals, respectively). Given the relatively consistent diet of crabeater seals, these findings suggest a shift in baseline food web structure occurred over the last 10,000 years, either through changes in foraging location or local shifts in biogeochemistry. For all species, N isotopic values are widely variable (e.g., 7.28 to 16.0 δ15N ‰ for the Weddell seal), which may be a result of

Qualitative and quantitative composition of microplastics particles during the expeditionary measurement program in the South-Eastern Baltic Sea

Science.gov (United States)

Esiukova, Elena; Bagaeva, Margarita; Chubarenko, Natalia

2016-04-01

According to the tasks of the Russian Science Foundation project "Physical and dynamical properties of marine microplastics particles and their transport in a basin with vertical and horizontal salinity gradient on the example of the Baltic Sea" number 15-17-10020, a comprehensive expeditionary program of measurements in the South-Eastern Baltic started. The project is aimed at finding solutions for a number of problems caused by superfluous plastic pollution in the World Ocean and, in particular, in the Baltic Sea. This pollution has been accumulating for years and just recently it has become obvious that only multidisciplinary approach (geographical, biological, chemical, etc.) to the issues related to the processes of transformation of properties and propagation of plastic particles will allow the study of physical aspects of the problem. During the first stage of the study samples should be selected from the water surface, water column at various horizons, bottom sediments in the Baltic Sea, from different areas at the beaches - in order to further examine the qualitative and quantitative composition of microplastic particles in different seasons for different hydrophysical situations. Reconnaissance survey was begun to choose the fields for research close to point and distributed sources of microplastics. Preference is given to those beaches that are exposed to maximum anthropogenic pollution: areas around the town of Baltiysk, the northern part of the Vistula Spit (near the settlement of Kosa), and the Sambia peninsula coast (settlements of Yantarny, Donskoye, Primorye, Kulikovo, towns of Svetlogorsk, Pionersky, Zelenogradsk). Locations for experimental sites were found in order to assess time for formation of microplastics (Vistula Spit, Kosa settlement). In June-November, 2015 there were 5 expeditions in the waters of the South-Eastern Baltic, 7 expeditions along the coast line of the Baltic Sea (in Kaliningrad Oblast), and 5 expeditions to the Vistula

Glacial-interglacial vegetation dynamics in South Eastern Africa coupled to sea surface temperature variations in the Western Indian Ocean

Directory of Open Access Journals (Sweden)

L. M. Dupont

2011-11-01

Full Text Available Glacial-interglacial fluctuations in the vegetation of South Africa might elucidate the climate system at the edge of the tropics between the Indian and Atlantic Oceans. However, vegetation records covering a full glacial cycle have only been published from the eastern South Atlantic. We present a pollen record of the marine core MD96-2048 retrieved by the Marion Dufresne from the Indian Ocean ∼120 km south of the Limpopo River mouth. The sedimentation at the site is slow and continuous. The upper 6 m (spanning the past 342 Ka have been analysed for pollen and spores at millennial resolution. The terrestrial pollen assemblages indicate that during interglacials, the vegetation of eastern South Africa and southern Mozambique largely consisted of evergreen and deciduous forests. During glacials open mountainous scrubland dominated. Montane forest with Podocarpus extended during humid periods was favoured by strong local insolation. Correlation with the sea surface temperature record of the same core indicates that the extension of mountainous scrubland primarily depends on sea surface temperatures of the Agulhas Current. Our record corroborates terrestrial evidence of the extension of open mountainous scrubland (including fynbos-like species of the high-altitude Grassland biome for the last glacial as well as for other glacial periods of the past 300 Ka.

Estimation of past sea-level variations based on ground-penetrating radar mapping of beach-ridges - preliminary results from Feddet, Faxe Bay, eastern Denmark

DEFF Research Database (Denmark)

Hede, Mikkel Ulfeldt; Nielsen, Lars; Clemmensen, Lars B

2011-01-01

Estimates of past sea-level variations based on different methods and techniques have been presented in a range of studies, including interpretation of beach ridge characteristics. In Denmark, Holocene beach ridge plains have been formed during the last c. 7700 years, a period characterised by both...... isostatic uplift and changes in eustatic sea-level, and therefore represent an archive of past relative sea-level variations. Here, we present preliminary results from investigation of beach ridges from Feddet, a small peninsula located in Faxe Bay (Baltic Sea) in the eastern part of Denmark. Feddet has...... been chosen as a key-locality in this project, as it is located relatively close to the current 0-isobase of isostatic rebound. GPR reflection data have been acquired with shielded 250 MHz Sensors & software antennae along a number of profile lines across beach ridge and swale structures of the Feddet...

Microfossils, a Key to Unravel Cold-Water Carbonate Mound Evolution through Time: Evidence from the Eastern Alboran Sea.

Directory of Open Access Journals (Sweden)

Claudio Stalder

Full Text Available Cold-water coral (CWC ecosystems occur worldwide and play a major role in the ocean's carbonate budget and atmospheric CO2 balance since the Danian (~65 m.y. ago. However their temporal and spatial evolution against climatic and oceanographic variability is still unclear. For the first time, we combine the main macrofaunal components of a sediment core from a CWC mound of the Melilla Mounds Field in the Eastern Alboran Sea with the associated microfauna and we highlight the importance of foraminifera and ostracods as indicators of CWC mound evolution in the paleorecord. Abundances of macrofauna along the core reveal alternating periods dominated by distinct CWC taxa (mostly Lophelia pertusa, Madrepora oculata that correspond to major shifts in foraminiferal and ostracod assemblages. The period dominated by M. oculata coincides with a period characterized by increased export of refractory organic matter to the seafloor and rather unstable oceanographic conditions at the benthic boundary layer with periodically decreased water energy and oxygenation, variable bottom water temperature/density and increased sediment flow. The microfaunal and geochemical data strongly suggest that M. oculata and in particular Dendrophylliidae show a higher tolerance to environmental changes than L. pertusa. Finally, we show evidence for sustained CWC growth during the Alleröd-Younger-Dryas in the Eastern Alboran Sea and that this period corresponds to stable benthic conditions with cold/dense and well oxygenated bottom waters, high fluxes of labile organic matter and relatively strong bottom currents.

Study of dissolved oxygen content in the Eastern Bosporus Strait (Peter the Great Bay, Sea of Japan)

Science.gov (United States)

Grigoryeva, N. I.

2017-09-01

Seasonal changes in the dissolved oxygen (DO) content in water were analyzed based on long-term observations (2006-2013) in the Eastern Bosporus Strait (Peter the Great Bay, Sea of Japan). It was found that the monthly average DO concentrations at the bottom of the strait were significantly lower in summer than the average annual long-term data. The minimum DO contents were recorded during four months, from July to October. It was shown that the DO content in water depended on changes in current directions in the strait: lower DO contents resulted from hypoxic water inflow, mostly from Amur Bay.

Multiple distant origins for green sea turtles aggregating off Gorgona Island in the Colombian eastern Pacific.

Directory of Open Access Journals (Sweden)

Diego F Amorocho

Full Text Available Mitochondrial DNA analyses have been useful for resolving maternal lineages and migratory behavior to foraging grounds (FG in sea turtles. However, little is known about source rookeries and haplotype composition of foraging green turtle aggregations in the southeastern Pacific. We used mitochondrial DNA control region sequences to identify the haplotype composition of 55 green turtles, Chelonia mydas, captured in foraging grounds of Gorgona National Park in the Colombian Pacific. Amplified fragments of the control region (457 bp revealed the presence of seven haplotypes, with haplotype (h and nucleotide (π diversities of h = 0.300±0.080 and π = 0.009±0.005 respectively. The most common haplotype was CMP4 observed in 83% of individuals, followed by CMP22 (5%. The genetic composition of the Gorgona foraging population primarily comprised haplotypes that have been found at eastern Pacific rookeries including Mexico and the Galapagos, as well as haplotypes of unknown stock origin that likely originated from more distant western Pacific rookeries. Mixed stock analysis suggests that the Gorgona FG population is comprised mostly of animals from the Galapagos rookery (80%. Lagrangian drifter data showed that movement of turtles along the eastern Pacific coast and eastward from distant western and central Pacific sites was possible through passive drift. Our results highlight the importance of this protected area for conservation management of green turtles recruited from distant sites along the eastern Pacific Ocean.

Multiple distant origins for green sea turtles aggregating off Gorgona Island in the Colombian eastern Pacific.

Science.gov (United States)

Amorocho, Diego F; Abreu-Grobois, F Alberto; Dutton, Peter H; Reina, Richard D

2012-01-01

Mitochondrial DNA analyses have been useful for resolving maternal lineages and migratory behavior to foraging grounds (FG) in sea turtles. However, little is known about source rookeries and haplotype composition of foraging green turtle aggregations in the southeastern Pacific. We used mitochondrial DNA control region sequences to identify the haplotype composition of 55 green turtles, Chelonia mydas, captured in foraging grounds of Gorgona National Park in the Colombian Pacific. Amplified fragments of the control region (457 bp) revealed the presence of seven haplotypes, with haplotype (h) and nucleotide (π) diversities of h = 0.300±0.080 and π = 0.009±0.005 respectively. The most common haplotype was CMP4 observed in 83% of individuals, followed by CMP22 (5%). The genetic composition of the Gorgona foraging population primarily comprised haplotypes that have been found at eastern Pacific rookeries including Mexico and the Galapagos, as well as haplotypes of unknown stock origin that likely originated from more distant western Pacific rookeries. Mixed stock analysis suggests that the Gorgona FG population is comprised mostly of animals from the Galapagos rookery (80%). Lagrangian drifter data showed that movement of turtles along the eastern Pacific coast and eastward from distant western and central Pacific sites was possible through passive drift. Our results highlight the importance of this protected area for conservation management of green turtles recruited from distant sites along the eastern Pacific Ocean.

Numerical modelling of the buoyant marine microplastics in the South-Eastern Baltic Sea

Science.gov (United States)

Bagaev, Andrei; Mizyuk, Artem; Chubarenko, Irina; Khatmullilna, Liliya

2017-04-01

Microplastics is a burning issue in the marine pollution science. Its sources, ways of propagation and final destiny pose a lot of questions to the modern oceanographers. Hence, a numerical model is an optimal tool for reconstruction of microplastics pathways and fate. Within the MARBLE project (lamp.ocean.ru), a model of Lagrangian particles transport was developed. It was tested coupled with oceanographic transport fields from the operational oceanography product of Copernicus Marine Monitoring Environment Service. Our model deals with two major types of microplastics such as microfibres and buoyant spheroidal particles. We are currently working to increase the grid resolution by means of the NEMO regional configuration for the south-eastern Baltic Sea. Several expeditions were organised to the three regions of the Baltic Sea (the Gotland, the Bornholm, and the Gdansk basins). Water samples from the surface and different water layers were collected, processed, and analysed by our team. A set of laboratory experiments was specifically designed to establish the settling velocity of particles of various shapes and densities. The analysis in question provided us with the understanding necessary for the model to reproduce the large-scale dynamics of microfibres. In the simulation, particles were spreading from the shore to the deep sea, slowly sinking to the bottom, while decreasing in quantity due to conditional sedimentation. Our model is expected to map out the microplastics life cycle and to account for its distribution patterns under the impact of wind and currents. For this purpose, we have already included the parameterization for the wind drag force applied to a particle. Initial results of numerical experiments seem to indicate the importance of proper implicit parameterization of the particle dynamics at the vertical solid boundary. Our suggested solutions to that problem will be presented at the EGU-2017. The MARBLE project is supported by Russian Science

Isotopic characteristics of shells Mytilus galloprovincialis from eastern coastal area of Adriatic Sea

Directory of Open Access Journals (Sweden)

Tjaša Kanduč

2006-06-01

Full Text Available Samples of Mytilus galloprovincialis were collected from entire Eastern Adriatic coast to determine δ18O and δ13C performed on calcite and aragonite shell layers. The aim of this work was to check whether shells of M. galloprovincialis are good environmental indicators (water temperature, salinity. Based on measured isotopic composition of oxygen in shell layers and assumed isotopic composition in water temperatures of calcite and aragonite of shell layers were calculated. The calculated temperatures for M. galloprovincialis shell growth of calcite and aragonite shell layer are in good agreement with measured temperatures of sea water. According to our results of δ18O and δ13C in shell layers we canseparate the locations of the investigated area into three groups: those with more influence of fresh water, those with less influence of fresh water and those of marine environments.

Random Forest population modelling of striped and common-bottlenose dolphins in the Gulf of Taranto (Northern Ionian Sea, Central-eastern Mediterranean Sea)

Science.gov (United States)

Carlucci, Roberto; Cipriano, Giulia; Paoli, Chiara; Ricci, Pasquale; Fanizza, Carmelo; Capezzuto, Francesca; Vassallo, Paolo

2018-05-01

This study provides the first estimates of density and abundance of the striped dolphin Stenella coeruleoalba and common bottlenose dolphin Tursiops truncatus in the Gulf of Taranto (Northern Ionian Sea, Central Mediterranean Sea) and identifies the predictive variables mainly influencing their occurrence and concentration in the study area. Conventional Distance Sampling (CDS) and the Delta approach on Random Forest (DaRF) methods have been applied to sightings data collected between 2009 and 2016 during standardized vessel-based surveys, providing similar outcomes. The mean value of density over the entire study area was 0.72 ± 0.26 specimens/km2 for the striped dolphin and 0.47 ± 0.09 specimens/km2 for the common bottlenose dolphin. The abundance estimated by DaRF in the Gulf of Taranto was 10080 ± 3584 specimens of S. coeruleoalba and 6580 ± 1270 specimens of T. truncatus, respectively. Eight predictive variables were selected, considering both the local physiographic features and human activities existing in the investigated area. The explanatory variables depth, distance from the coast, distance from industrial areas and distance from areas exploited by fishery seem to play a key role in influencing the spatial distribution of both species, whereas the geomorphological variables proved to be the most significant factors shaping the concentration of both dolphins. The establishment of a Specially Protected Area of Mediterranean Importance (SPAMI) according the SPA/BD Protocol in the Gulf of Taranto is indicated as an effective management tool for the conservation of both dolphin populations in the Central-eastern Mediterranean Sea.

Indications of low macrobenthic activity in the deep sediments of the eastern Mediterranean Sea

Directory of Open Access Journals (Sweden)

Daniela Basso

2004-12-01

Full Text Available The fluxes and budget of organic matter from the oligotrophic surface waters of the eastern Mediterranean to the deep waters are poorly known, and little information is available on past and present macrobenthic activity on the sea floor. Evidence of macrobenthic activity can be direct, through recovery of living organisms or their autochthonous skeletal remains, or indirect, through bioturbation and trace fossils. The evidence of biological activity in deep eastern Mediterranean sediments has been evaluated and compared through 210Pb profiles from box-cores and study of dredge samples from sites on Medina Rise (1374 m water depth, the Messina Abyssal Plain (4135 m and several sites along the Mediterranean Ridge, SW and S of Crete (1783 to 3655 m. All these sites are remote from the continental shelves, so the biological benthic activity is expected to depend primarily on primary production from surface waters. The results show that present-day macrobenthos and trace fossils are generally scarce, especially at depths > 2500 m. This observation is supported by surface sediment 210Pb excess distributions that show a surface mixed layer (SML 2500 m. The historical layer of some box-cores and the Pleistocene hardgrounds collected in the Cleft area (Mediterranean Ridge do, however, record a macrobenthic activity that is apparently more intense than at present, which may be related to higher primary production of the Pleistocene glacial intervals. In contrast with most areas of the present-day deep eastern Mediterranean which depend on surface primary production based on photosynthesis, a relatively dense and diversified macrobenthic community based on chemosynthesis has been recognised at depths > 1100 m on the Napoli Dome mud volcano in the Olimpi area, and on the Kazan and other mud volcanoes in the Anaximander Mountains.

Biogeographical homogeneity in the eastern Mediterranean Sea - I: the opisthobranchs (Mollusca: Gastropoda from Lebanon

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F. CROCETTA

2013-07-01

Full Text Available A reviewed knowledge of the opisthobranch species from Lebanon (eastern Mediterranean Sea, based on literature records (scattered throughout various papers published over a period of more than 150 years and recently collected material (1999-2002 within the CEDRE framework and other samples, is presented, yielding a total number of 35 taxa recorded from the Lebanese shores identified to species level. Special emphasis has mainly been given to the alien species, for which scattered notes are also given. The known opisthobranch biota is composed of 22 native (~ 63%, 12 alien (~ 34% and one cryptogenic (~ 3% taxa. Eleven of these (Berthella aurantiaca, B. ocellata, Aplysia fasciata, Felimare picta, Felimida britoi, F. luteorosea, F. purpurea, Phyllidia flava, Dendrodoris grandiflora, D. limbata and Aeolidiella alderi constitute new records for the Lebanese fauna, whilst the examined material of a further seven species (Elysia grandifolia, Pleurobranchus forskalii, Aplysia dactylomela, Bursatella leachii, Syphonota geographica, Goniobranchus annulatus, Flabellina rubrolineata anecdotally cited from Lebanon on the basis of the samples here studied, is here first explained. One additional taxon belonging to the genus Haminoea has been identified to genus level only. Despite the searching effort poning the basis of the material analyzed here, data reported clearly suggest that strong investments are still needed for a better understanding of the eastern Mediterranean opisthobranch fauna.

Prevalence of immunoglobulin E-mediated food allergy in 6-9-year-old urban schoolchildren in the eastern Black Sea region of Turkey.

Science.gov (United States)

Orhan, F; Karakas, T; Cakir, M; Aksoy, A; Baki, A; Gedik, Y

2009-07-01

The prevalence of adverse reactions to food in childhood in Turkey is not known. We aimed to investigate the prevalence and characteristics of IgE-mediated food allergies (FAs) in 6-9-year-old urban schoolchildren. This cross-sectional study recruited 3500 of the randomly selected 6-9-year-old urban schoolchildren from the eastern Black Sea region of Turkey during 2006. Following a self-administered questionnaire completed by the parents and the child, consenting children were invited for skin prick tests (SPTs) and oral food challenges. Children with suspected IgE-mediated FA were skin prick tested with a predefined panel of food allergens (milk, hen's egg, soy, wheat, peanut, fish, and hazelnut), aeroallergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat, dog, Alternaria, grass pollen mix, weed pollen mix, and tree pollen mix), and food allergens reported in the questionnaire. All children with a positive SPT to any food were invited for a double-blind, placebo-controlled food challenge (DBPCFC). The prevalence of IgE-mediated FA was established using DBPCFCs. The response rate to the questionnaire was 78.2% (2739/3500). The estimated prevalence of parental-reported IgE-mediated FA was 5.7% (156/2739) [95% confidence interval (CI), 4.83-6.57%]. The rate of sensitization to the food allergens was 33.1% (48/145) in the parental-reported group. The confirmed prevalence of IgE-mediated FA by means of DBPCFC in 6-9-year-old urban schoolchildren living in the eastern Black Sea region of Turkey was 0.80% (22/2739) (95% CI, 0.47-1.13%). The most common allergenic foods were beef (31.8%), cow's milk (18.1%), cocoa (18.1%), hen's egg (13.6%), and kiwi (13.6%). The rate of reported IgE-mediated FA was significantly higher than clinically confirmed FA by means of DBPCFC (odds ratio, 7.46; 95% CI, 4.67-12.01; Pfoods was different and somewhat unique to the eastern Black Sea region of Turkey when compared with western countries.

Cadmium, copper and iron in the Scotia Sea, Weddell Sea and Weddell/Scotia Confluence (Antarctica)

NARCIS (Netherlands)

Nolting, R.F.; Baar, H.J.W. de; Bennekom, A.J. van; Masson, A.

1991-01-01

Until recently, little was known about trace metals in the Southern Ocean. Vertical profiles and surface water sections along 49°W exhibit Cd concentrations of 0.2–0.8 nM, increasing with depth, as for phosphate. A linear relationship between Cd and phosphate exists as in other oceans; however, the

Movement of a female polar bear (Ursus maritimus) in the Kara Sea during the summer sea-ice break-up.

Science.gov (United States)

Rozhnov, V V; Platonov, N G; Naidenko, S V; Mordvintsev, I N; Ivanov, E A

2017-01-01

The polar bear movement trajectory in relation to onset date of the sea-ice break-up was studied in the coastal zone of the Taimyr Peninsula, eastern part of the Kara Sea, using as an example a female polar bear tagged by a radio collar with an Argos satellite transmitter. Analysis of the long-term pattern of ice melting and tracking, by means of satellite telemetry, of the female polar bear who followed the ice-edge outgoing in the north-eastern direction (in summer 2012) suggests that direction of the polar bear movement depends precisely on the direction of the sea-ice cover break-up.

Tectonostratigraphy of the Southern Part of Papua and Arafura Sea, Eastern Indonesia

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Bhakti H. Harahap

2014-06-01

Full Text Available DOI: 10.17014/ijog.v7i3.145Sedimentary history and stratigraphy of the Papua and Arafura Sea areas, eastern Indonesia, are gained from surface geological mapping combined with published data from oil companies. Development of some sedimentary units demonstrates that the tectonism have influenced sedimentation of such units comprising a succession of Phanerozoic rocks developing in a stable continental margin. The succession underlain by Cambrian-Silurian-Devonian metamorphic rocks consists of Tuaba, Kariem, Awitagoh, and Kemum Formation, and Modio Dolomite (Pre-Rift Phase. These rocks having been intruded by Late Permian-Middle Triassic granitoids and Carboniferous granite, are unconformably overlain by Late Carboniferous to Cretaceous siliciclastic-rich units comprising Aifam Group and Tipuma Formation (syn-Rift Phase and Kembelangan Group (Mesozoic Passive Margin Post-Rift. The Aifam Group is separated by a regionally continuous boundary on its top contact from the Triassic-Early Jurassic Tipuma Formation, which filled the block-faulted rift valley subbasins of continentally deposited red beds in the breakup stage. Regionally, developed erosion surfaces of the breakup unconformity have separated these red beds from generally transgressive post-breakup deposits of the Jurassic to Cretaceous marine sediments of the Kembelangan Group. Beach to shallow marine-glauconitic sandstone and shale of the group pass upward into shelf mudstone. Relative sea level fall related to the tectonic stability of the area led to the development of Eocene to Late Miocene platform carbonates of the New Guinea Limestone Supergroup which occurred in the entire island of Papua and the southern of Arafura that overlie these non-carbonate units (Tertiary passive margin. It is separated from the siliciclastic-rich packages by the Tertiary - Pre-Tertiary boundary. The sea level fluctuation within the group was also recorded during the formation of thin, discontinuous

Changes in distributional patterns of plaice Pleuronectes platessa in the central and eastern North Sea; do declining nutrient loadings play a role?

DEFF Research Database (Denmark)

Støttrup, Josianne Gatt; Munk, Peter; Kodama, Masashi

2017-01-01

of offshore habitats as nursery areas by juvenile plaice in the North Sea appears not related to water depth per se but driven by specific processes dominating in near-shore areas and may be related to changes in nutrient loadings. This point to the importance of separating more general depth-related factors....... For the same time period available time series data on nutrient conditions in the coastalNorth Sea area showthat the freshwater nitrogen loading has decreased by about 50%. While nutrient concentrations in the ambient environment have been shown to influence growth in juvenile plaice through influence...... on their prey, we here inspect the potential linkage between distributional changes in plaice and the decline in nutrient loading.We compare plaice observations in coastal areas in the eastern North Sea,which have experienced large changes in eutrophication,with observations for the Dogger Bank, a large...

Nitrogen fixation rates in the eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Ahmed, A.; Gauns, M.; Kurian, S.; Bardhan, P.; Pratihary, A.K.; Naik, H.; Shenoy, D.M.; Naqvi, S.W.A.

The Arabian Sea experiences bloom of the diazotroph Trichodesmium during certain times of the year when optimal sea surface temperature and oligotrophic condition favour their growth. We measured nitrogen fixation rates in the euphotic zone during...

Intraseasonal meridional current variability in the eastern equatorial Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Ogata, T.; Sasaki, H.; Murty, V.S.N.; Sarma, M.S.S.; Masumoto, Y.

. [2007] demonstrate the possibility of the air-sea interac- tion in the eastern Indian Ocean at the intraseasonal time- scale by analyzing observed and simulated data. Recent studies also reveal that multiscale air-sea interactions be- tween intraseasonal...

Taxonomy of the early life stages of arrowtooth flounder (Atheresthes stomias) and Kamchatka flounder (A. evermanni) in the eastern Bering Sea, with notes on distribution and condition

Science.gov (United States)

De Forest, Lisa; Duffy-Anderson, J. T.; Heintz, R. A.; Matarese, A. C.; Siddon, E. C.; Smart, T. I.; Spies, I. B.

2014-11-01

Arrowtooth flounder (Atheresthes stomias) and Kamchatka flounder (A. evermanni) are closely related flatfish species that co-occur in the eastern Bering Sea. As adults, arrowtooth flounder can be distinguished from Kamchatka flounder; however, larvae and early juveniles can only be indentified to the genus level due to morphological similarities. This has precluded studies of ecology for the early life stages of both species in the eastern Bering Sea. In this study, we developed a genetic technique to identify the larvae and early juveniles of the two species using mtDNA cytochrome oxidase subunit I (COI). Genetically identified specimens were then examined to determine a visual identification method based on pigment patterns and morphology. Specimens 6.0-12.0 mm SL and≥18.0 mm SL can be identified to the species level, but species identification of individuals 12.1-17.9 mm SL by visual means alone remains elusive. The distribution of larvae (<25.0 mm SL) of both arrowtooth flounder and Kamchatka flounder is similar in the eastern Bering Sea; however, juvenile (≥25.0 mm SL) Kamchatka flounder occur closer to the shelf break and in deeper water than juvenile arrowtooth flounder. Condition was determined for larvae and juveniles of each species by analyzing lipid content (%) and energy density (kJ/g dry mass). Kamchatka flounder larvae on average had higher lipid content than arrowtooth flounder larvae, but were also larger on average than arrowtooth flounder larvae in the summer. When corrected for length, both species had similar lipid content in the larval and juvenile stages.

Short-term variability in halocarbons in relation to phytoplankton pigments in coastal waters of the central eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Roy, R.

The sampling locations, along the Candolim Time-Series Section (CaTS), in coastal waters of the eastern Arabian Sea, are shown in Fig. 1. Water depth at these stations varied between 6 m (G1) and 28 m (G5) whereas samples at G5 were generally collected from a... times. 6 3. Results The short-term variability of halocarbons and pigments has been presented for CaTS station G5, with a brief on hydrography. However, data from stations G1- G4 have been used to derive statistically significant relationships among...

The ESASSI-08 cruise in the South Scotia Ridge region: Water masses, currents, and the ASF

Science.gov (United States)

Palmer, M.; Gomis, D.; Flexas, M. M.; Jordà, G.; Orsi, A. H.

2009-04-01

The ESASSI-08 oceanographic cruise carried out in January 2008 was the major milestone of ESASSI, the Spanish component of SASSI (a core project of the International Polar Year devoted to study the shelf-slope exchanges in different locations of Antarctica). The specific objectives of ESASSI, the sampling strategy and the overall distribution of the main variables across the 11 sections covered by the cruise are presented in a poster. Here we focus on three specific issues: i) the observation of strong tidal currents over some of the sampled slopes; ii) the path of the Antarctic Slope Front (ASF) over the SSR; and iii) the outflow of dense, ventilated water from the Weddell Sea into the South Scotia Sea. The main results are: i) Strong tidal currents with a significant diurnal component were observed over the southern slope of the SSR. Three tidal models are compared with the observations and used to de-tide ADCP currents. ii) The signature of the ASF is clearly detected on the southern slopes of the SSR (on the Weddell Sea flank). Over the northern slopes (the Scotia Sea flank), however, only weak signatures of frontal structures are observed; an in-depth biochemical analysis will be required to link the structures observed over the two flanks of the SSR. What seems clear is that the ASF does not extend further than Elephant Island, since southwestward of that island the shelf and the slope are fully occupied by Circumpolar Deep Water (CDW) from the Antarctic Circumpolar Current. iii) The shallower component of Weddell Sea Deep Water (Upper WSDW) flows over the SSR and pours into the Scotia Sea except to the east of Elephant Island, where the channels are less than 1500 m deep. The densest component of WSDW (Lower WSDW) is observed at both flanks of the SSR, but again a more detailed analysis of biochemical data will be required to prove a direct flux of this water mass across the SSR. Weddell Sea Bottom Water (WSBW) is not observed in any of the sampled sections.

Hydrological, plankton and pigment observations in the Makassar Strait, Madura Strait and Eastern Java Sea by the R.V. Samudera, April 16 to May 19, 1975 (NODC Accession 7700306)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton and chemical data were collected using net and bottle casts from the R.V. SAMUDERA in the Makassar Strait, Madura Strait and Eastern Java Sea from 16...

Analysis of the projected regional sea-ice changes in the Southern Ocean during the twenty-first century

Energy Technology Data Exchange (ETDEWEB)

Lefebvre, W.; Goosse, H. [Universite Catholique de Louvain, Institut d' Astronomie et de Geophysique Georges Lemaitre, Louvain-la-Neuve (Belgium)

2008-01-15

Using the set of simulations performed with atmosphere-ocean general circulation models (AOGCMs) for the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4), the projected regional distribution of sea ice for the twenty-first century has been investigated. Averaged over all those model simulations, the current climate is reasonably well reproduced. However, this averaging procedure hides the errors from individual models. Over the twentieth century, the multimodel average simulates a larger sea-ice concentration decrease around the Antarctic Peninsula compared to other regions, which is in qualitative agreement with observations. This is likely related to the positive trend in the Southern Annular Mode (SAM) index over the twentieth century, in both observations and in the multimodel average. Despite the simulated positive future trend in SAM, such a regional feature around the Antarctic Peninsula is absent in the projected sea-ice change for the end of the twenty-first century. The maximum decrease is indeed located over the central Weddell Sea and the Amundsen-Bellingshausen Seas. In most models, changes in the oceanic currents could play a role in the regional distribution of the sea ice, especially in the Ross Sea, where stronger southward currents could be responsible for a smaller sea-ice decrease during the twenty-first century. Finally, changes in the mixed layer depth can be found in some models, inducing locally strong changes in the sea-ice concentration. (orig.)

A GIS Approach for Reconstructing the Litorina Sea Lagoon in Tolkuse-Rannametsa Area, Eastern Gulf of Riga.

Science.gov (United States)

Habicht, Hando-Laur; Rosentau, Alar; Jõeleht, Argo; Hang, Tiit; Kohv, Marko

2015-04-01

The eastern coast of the Gulf of Riga in the NE Baltic Sea is characterized by slow post-glacial isostatic uplift (about 1mm/yr) and slowly undulating low topography. Therefore even small increases in sea-level can easily lead to the flooding of considerable areas. The complex deglaciation history of the Baltic Sea area left, at times, south western Estonia submerged, while at other times, it emerged as terrestrial land. Different transgressive and regressive development stages of the Baltic Sea did not only shape the landscape, but also influenced the locations of the Stone Age settlements which were closely bound to the coastal areas which also include estuaries and lagoonal systems. The coastal region of the Gulf of Riga is abundant in Meso- and Neolithic settlement sites. The present study combines LiDAR, ground-penetrating radar (GPR) and geological data to reconstruct development of the Litorina Sea lagoon in Tolkuse-Rannametsa area and to create prognostic palaeogeographic maps in order to search for Meso- and Neolithic coastal settlement sites. Over 47 km of GPR profiling was done; sediments were described and dated in 37 cores two riverbank outcrops. Diatoms were analysed in the master core. A semi-automatic method for the removal of modern anthropogenic features from LiDAR derived digital elevation model (DEM) was developed, tested and used. In modelling process the impact of sedimentary processes subsequent to the time being modelled was taken into account by employing a backstripping methodology. The differential glacio-isostatic uplift within the study area was taken into account by using interpolated water-level surfaces. Palaeogeographic reconstructions shed new light into region's post-glacial coastal evolution and enabled us to suggest the possible locations of the Stone Age settlements with some of the proposed areas buried under up to 3 m thick peat layer. The results of the current study provide new chronological and shore displacement data

Sea ice dynamics across the Mid-Pleistocene transition in the Bering Sea.

Science.gov (United States)

Detlef, H; Belt, S T; Sosdian, S M; Smik, L; Lear, C H; Hall, I R; Cabedo-Sanz, P; Husum, K; Kender, S

2018-03-05

Sea ice and associated feedback mechanisms play an important role for both long- and short-term climate change. Our ability to predict future sea ice extent, however, hinges on a greater understanding of past sea ice dynamics. Here we investigate sea ice changes in the eastern Bering Sea prior to, across, and after the Mid-Pleistocene transition (MPT). The sea ice record, based on the Arctic sea ice biomarker IP 25 and related open water proxies from the International Ocean Discovery Program Site U1343, shows a substantial increase in sea ice extent across the MPT. The occurrence of late-glacial/deglacial sea ice maxima are consistent with sea ice/land ice hysteresis and land-glacier retreat via the temperature-precipitation feedback. We also identify interactions of sea ice with phytoplankton growth and ocean circulation patterns, which have important implications for glacial North Pacific Intermediate Water formation and potentially North Pacific abyssal carbon storage.

Role of the Tropical Pacific in recent Antarctic Sea-Ice Trends

Science.gov (United States)

Codron, F.; Bardet, D.; Allouache, C.; Gastineau, G.; Friedman, A. R.; Douville, H.; Voldoire, A.

2017-12-01

The recent (up to 2016) trends in Antarctic sea-ice cover - a global increase masking a dipole between the Ross and Bellingshausen-Weddel seas - are still not well understood, and not reproduced by CMIP5 coupled climate models. We here explore the potential role of atmospheric circulation changes around the Amundsen Sea, themselves possibly forced by tropical SSTs, an explanation that has been recently advanced. As a first check on this hypothesis, we compare the atmospheric circulation trends simulated by atmospheric GCMs coupled with an ocean or with imposed SSTs (AMIP experiment from CMIP5); the latter being in theory able to reproduce changes caused by natural SST variability. While coupled models simulate in aggregate trends that project on the SAM structure, strongest in summer, the AMIP simulations add in the winter season a pronounced Amundsen Sea Low signature (and a PNA signature in the northern hemisphere) both consistent with a Niña-like trend in the tropical Pacific. We then use a specific coupled GCM setup, in which surface wind anomalies over the tropical Pacific are strongly nudged towards the observed ones, including their interannual variability, but the model is free to evolve elsewhere. The two GCMs used then simulate a deepening trend in the Amundsen-Sea Low in winter, and are able to reproduce a dipole in sea-ice cover. Further analysis shows that the sea-ice dipole is partially forced by surface heat flux anomalies in early winter - the extent varying with the region and GCM used. The turbulent heat fluxes then act to damp the anomalies in late winter, which may however be maintained by ice-albedo feedbacks.

Variability in the air–sea interaction patterns and timescales within the south-eastern Bay of Biscay, as observed by HF radar data

Directory of Open Access Journals (Sweden)

A. Fontán

2013-04-01

Full Text Available Two high-frequency (HF radar stations were installed on the coast of the south-eastern Bay of Biscay in 2009, providing high spatial and temporal resolution and large spatial coverage of currents in the area for the first time. This has made it possible to quantitatively assess the air–sea interaction patterns and timescales for the period 2009–2010. The analysis was conducted using the Barnett–Preisendorfer approach to canonical correlation analysis (CCA of reanalysis surface winds and HF radar-derived surface currents. The CCA yields two canonical patterns: the first wind–current interaction pattern corresponds to the classical Ekman drift at the sea surface, whilst the second describes an anticyclonic/cyclonic surface circulation. The results obtained demonstrate that local winds play an important role in driving the upper water circulation. The wind–current interaction timescales are mainly related to diurnal breezes and synoptic variability. In particular, the breezes force diurnal currents in waters of the continental shelf and slope of the south-eastern Bay. It is concluded that the breezes may force diurnal currents over considerably wider areas than that covered by the HF radar, considering that the northern and southern continental shelves of the Bay exhibit stronger diurnal than annual wind amplitudes.

Viruses and Protists Induced-mortality of Prokaryotes around the Antarctic Peninsula during the Austral Summer

KAUST Repository

Vaque, Dolors; Boras, Julia A.; Torrent-Llagostera, Francesc; Agusti, Susana; Arrieta, J M; Lara, Elena; Castillo, Yaiza M.; Duarte, Carlos M.; Sala, Maria M.

2017-01-01

During the Austral summer 2009 we studied three areas surrounding the Antarctic Peninsula: the Bellingshausen Sea, the Bransfield Strait and the Weddell Sea. We aimed to investigate, whether viruses or protists were the main agents inducing prokaryotic mortality rates, and the sensitivity to temperature of prokaryotic heterotrophic production and mortality based on the activation energy (Ea) for each process. Seawater samples were taken at seven depths (0.1-100 m) to quantify viruses, prokaryotes and protists abundances, and heterotrophic prokaryotic production (PHP). Viral lytic production, lysogeny, and mortality rates of prokaryotes due to viruses and protists were estimated at surface (0.1-1 m) and at the Deep Fluorescence Maximum (DFM, 12-55 m) at eight representative stations of the three areas. The average viral lytic production ranged from 1.0 +/- 0.3 x 10(7) viruses ml(-1) d(-1) in the Bellingshausen Sea to1.3 +/- 0.7 x 10(7) viruses ml(-1) d(-1) in the Bransfield Strait, while lysogeny, when detectable, recorded the lowest value in the Bellingshausen Sea (0.05 +/- 0.05 x 10(7) viruses ml(-1) d(-1)) and the highest in the Weddell Sea (4.3 +/- 3.5 x 10(7) viruses ml(-1) d(-1)). Average mortality rates due to viruses ranged from 9.7 +/- 6.1 x 10(4) cells ml(-1) d(-1) in the Weddell Sea to 14.3 +/- 4.0 x 10(4) cells ml(-1) d(-1) in the Bellingshausen Sea, and were higher than averaged grazing rates in the Weddell Sea (5.9 +/- 1.1 x 10(4) cells ml(-1) d(-1)) and in the Bellingshausen Sea (6.8 +/- 0.9 x 10(4) cells ml-1 d(-1)). The highest impact on prokaryotes by viruses and main differences between viral and protists activities were observed in surface samples: 17.8 +/- 6.8 x 10(4) cells ml(-1) d(-1) and 6.5 +/- 3.9 x 10(4) cells ml(-1) d(-1) in the Weddell Sea; 22.1 +/- 9.6 x 10(4) cells ml(-1) d(-1) and 11.6 +/- 1.4 x 10(4) cells ml(-1) d(-1) in the Bransfield Strait; and 16.1 +/- 5.7 x 10(4) cells ml(-1) d(-1) and 7.9 +/- 2.6 x 10(4) cells ml(-1) d(-1) in

Viruses and Protists Induced-mortality of Prokaryotes around the Antarctic Peninsula during the Austral Summer

KAUST Repository

Vaque, Dolors

2017-03-27

During the Austral summer 2009 we studied three areas surrounding the Antarctic Peninsula: the Bellingshausen Sea, the Bransfield Strait and the Weddell Sea. We aimed to investigate, whether viruses or protists were the main agents inducing prokaryotic mortality rates, and the sensitivity to temperature of prokaryotic heterotrophic production and mortality based on the activation energy (Ea) for each process. Seawater samples were taken at seven depths (0.1-100 m) to quantify viruses, prokaryotes and protists abundances, and heterotrophic prokaryotic production (PHP). Viral lytic production, lysogeny, and mortality rates of prokaryotes due to viruses and protists were estimated at surface (0.1-1 m) and at the Deep Fluorescence Maximum (DFM, 12-55 m) at eight representative stations of the three areas. The average viral lytic production ranged from 1.0 +/- 0.3 x 10(7) viruses ml(-1) d(-1) in the Bellingshausen Sea to1.3 +/- 0.7 x 10(7) viruses ml(-1) d(-1) in the Bransfield Strait, while lysogeny, when detectable, recorded the lowest value in the Bellingshausen Sea (0.05 +/- 0.05 x 10(7) viruses ml(-1) d(-1)) and the highest in the Weddell Sea (4.3 +/- 3.5 x 10(7) viruses ml(-1) d(-1)). Average mortality rates due to viruses ranged from 9.7 +/- 6.1 x 10(4) cells ml(-1) d(-1) in the Weddell Sea to 14.3 +/- 4.0 x 10(4) cells ml(-1) d(-1) in the Bellingshausen Sea, and were higher than averaged grazing rates in the Weddell Sea (5.9 +/- 1.1 x 10(4) cells ml(-1) d(-1)) and in the Bellingshausen Sea (6.8 +/- 0.9 x 10(4) cells ml-1 d(-1)). The highest impact on prokaryotes by viruses and main differences between viral and protists activities were observed in surface samples: 17.8 +/- 6.8 x 10(4) cells ml(-1) d(-1) and 6.5 +/- 3.9 x 10(4) cells ml(-1) d(-1) in the Weddell Sea; 22.1 +/- 9.6 x 10(4) cells ml(-1) d(-1) and 11.6 +/- 1.4 x 10(4) cells ml(-1) d(-1) in the Bransfield Strait; and 16.1 +/- 5.7 x 10(4) cells ml(-1) d(-1) and 7.9 +/- 2.6 x 10(4) cells ml(-1) d(-1) in

AFSC/RACE/EcoFOCI: NPRB project number 926: Assessing the condition of walleye pollock, Theragra chalcogramma, larvae in the eastern Bering Sea with muscle-based flow cytometry cell cycle analysis

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Walleye pollock are an important component of the eastern Bering Sea ecosystem due to their vast numbers and biomass and are of great commercial importance. Their...

Currents in the Eastern Irish Sea

International Nuclear Information System (INIS)

Howarth, M.J.

1983-01-01

Low level radioactive waste is discharged from the nuclear re-processing plant at Sellafield, Cumbria. Its movement away from the discharge point is determined by the Irish Sea's dynamics, both for the soluble compounds and for those compounds which become attached to the sediment. Near Sellafield the tidal currents are weak and parallel to the shore, becoming stronger east/west to the north and south of the Isle of Man. Wind driven currents near Sellafield are predominantly north-westward, strongest near the coast, and oppose the other low frequency currents. Hence, the soluble effluent will initially be dispersed parallel to the shore by the weak tidal currents, moving episodically, southeastward during weak winds and northwestward during storms. Eventually it will leave the Irish Sea, flowing northward through the North Channel. (author)

75 FR 77602 - Endangered and Threatened Species; 90-Day Finding on Petitions To Delist the Eastern Distinct...

Science.gov (United States)

2010-12-13

... the Eastern Distinct Population Segment of the Steller Sea Lion AGENCY: National Marine Fisheries... delist the eastern Distinct Population Segment (DPS) of the Steller Sea Lion (Eumetopias jubatus) under...-implementing regulations issued by NMFS and the U.S. Fish and Wildlife Service (FWS) also establish procedures...

Skate Bathyraja spp. egg predation in the eastern Bering Sea.

Science.gov (United States)

Hoff, G R

2009-01-01

Predation on skate eggs by snails was examined for three skate species at seven nursery sites in three regions (north, middle and south) of the eastern Bering Sea. Mean predation levels were 6.46% for the Alaska skate Bathyraja parmifera, 2.65% for the Aleutian skate Bathyraja aleutica and 22.25% for the Bering skate Bathyraja interrupta. Predation levels were significantly higher at the middle and north sites than the south sites for all species combined. Predation levels decreased with increasing egg-case densities at all nursery sites, and the highest predation levels occurred where egg-case densities were very low. Predated egg-case density increased with increasing snail densities across all nursery sites examined. The Oregon triton Fusitriton oregonensis was the most abundant snail species at all nursery sites and displayed ability to drill holes in the egg case of B. parmifera. Holes left by predatory snails in egg cases of B. parmifera were significantly larger, and of different shape at the middle site compared to the south site. Holes in B. parmifera were also significantly larger than those in egg cases of B. interrupta across all sites examined. Egg cases of B. aleutica possess surface spines that cover the egg case and may inhibit predation by snails at a greater rate than that of the B. parmifera and B. interrupta, which have a smoother egg-case surface.

Source of Aegean Sea harbour porpoises

DEFF Research Database (Denmark)

Lockyer, Christina; Rosel, P. E.; Frantzis, A.

2003-01-01

Documented sightings of harbour porpoises in the Mediterranean are rare, although the species is common in the neighbouring North Atlantic and Black Sea. However, in the past 2 decades, 4 harbour porpoises Phocoena phocoena have been recorded in the northern Aegean Sea in the eastern Mediterranea...

Eddy Mediated Nutrient Pattern in the North Eastern Arabian Sea

Science.gov (United States)

Thachaparambil, M.; Moolakkal Antony, R.; B R, S.; V N, S.; N, C.; M, S.

2016-02-01

A Cold Core Eddy (CCE) mediated nutrient pattern in the North Eastern Arabian Sea (NEAS) is explained based on in situ measurments during March 2013 onboard FORV Sagar Sampada which was not reported earlier in the area. Samples for physical, chemical and biological parameters were collected in 5 stations along the diameter of the eddy and following standard protocols. The core of the CCE is identified at 21°20.38'N; 66°30.68'E with a diameter of 120Km. Earlier studies explaining the process and the forcing mechanism of the particular eddy records that, the eddy is short term (1-3 months) and is regular during the season. Surface waters were well oxygenated (>4.8 ml L-1) in the core. Surface value of nutrients viz., Nitrate, Nitrite, Silicate and phosphate in the core regions was 0.9µM, 0.01 µM, 0.5 µM and 0.7 µM respectively indicating upwelling in the core. Spring intermonsoon (SIM) is generally termed as a transition period between the active winter and summer seasons and as per earlier studies, high biological production and the regularly occurring Noctilica bloom is supported by the nutrient loading due to convective mixing during winter as well as regenerated production. However, present observations shows that, nutrient pumping due to the upwelling associated with the CCE also contributes for sustaining high biological production and are evident in the Chl a and mesozooplankton biovolume which records values of 4.35mg/m3 and 1.09ml/m3 respectively in the core. An intense Noctiluca blooms observed in the western flank of the eddy (Chl a 13.25 mg/m3; cell density 5.8×106 cells/litre), where Nitrate concentration records 1.04µM explains the role of such mesoscale processes in the sustenance of the HAB events. While eastern flank of the CCE showed typical open ocean condition of the season showing Nitrate 0.08µM; Chl a 0.23mg/m3; and phytoplankton cell density as 421 cells/litre. Keywords: Cold core eddy, nutrients, NEAS, SIM, biological production

Different Oceanographic Regimes in the Vicinity of the Antarctic Peninsula Reflected in Benthic Nematode Communities.

Directory of Open Access Journals (Sweden)

Freija Hauquier

Full Text Available Marine free-living nematode communities were studied at similar depths (~500 m at two sides of the Antarctic Peninsula, characterised by different environmental and oceanographic conditions. At the Weddell Sea side, benthic communities are influenced by cold deep-water formation and seasonal sea-ice conditions, whereas the Drake Passage side experiences milder oceanic conditions and strong dynamics of the Antarctic Circumpolar Current. This resulted in different surface primary productivity, which contrasted with observed benthic pigment patterns and varied according to the area studied: chlorophyll a concentrations (as a proxy for primary production were high in the Weddell Sea sediments, but low in the surface waters above; this pattern was reversed in the Drake Passage. Differences between areas were largely mirrored by the nematode communities: nematode densities peaked in Weddell stations and showed deeper vertical occurrence in the sediment, associated with deeper penetration of chlorophyll a and indicative of a strong bentho-pelagic coupling. Generic composition showed some similarities across both areas, though differences in the relative contribution of certain genera were noted, together with distinct community shifts with depth in the sediment at all locations.

Crust Structure Data of Seas Surrounding Turkey

International Nuclear Information System (INIS)

Maden, N.; Gelisli, K.

2007-01-01

Black Sea, Aegean, Mediterranean and Marmara Sea, which surround the Turkey, have not been examined with respect to the Geological, Geophysical and other natural sciences sufficiently. In fact, it is not attach importance the Turkish seas adequately and abandoned with respect to the scientific researches. The most important reason of this situation is the lack of the education of the Marine Sciences in the Turkish Universities. In this study, it is tried to construct a crustal structure data base of the surrounding seas of the Turkey by collecting crustal structure data sets done by different authors in different times so far. The data acquired in the base are collected from different data base sources by dragging. The Moho depth in the eastern and western basin of the Black sea is 22 km and 19 km, respectively. In the Marmara Sea the Moho depth is 24 km. The moho value in the southern Aegean is 20 km, in the northern Aegean the moho depth is 30 km. on the other hand, the moho depth value in the eastern and western basin of the Mediterranean Sea are 15-20 km and 25-30 km, respectively

Quantification of the early small-scale fishery in the north-eastern Baltic Sea in the late 17th century.

Science.gov (United States)

Verliin, Aare; Ojaveer, Henn; Kaju, Katre; Tammiksaar, Erki

2013-01-01

Historical perspectives on fisheries and related human behaviour provide valuable information on fishery resources and their exploitation, helping to more appropriately set management targets and determine relevant reference levels. In this study we analyse historical fisheries and fish trade at the north-eastern Baltic Sea coast in the late 17th century. Local consumption and export together amounted to the annual removal of about 200 tonnes of fish from the nearby sea and freshwater bodies. The fishery was very diverse and exploited altogether one cyclostome and 17 fish species with over 90% of the catch being consumed locally. The exported fish consisted almost entirely of high-valued species with Stockholm (Sweden) being the most important export destination. Due to rich political history and natural features of the region, we suggest that the documented evidence of this small-scale fishery should be considered as the first quantitative summary of exploitation of aquatic living resources in the region and can provide a background for future analyses.

Quantification of the early small-scale fishery in the north-eastern Baltic Sea in the late 17th century.

Directory of Open Access Journals (Sweden)

Aare Verliin

Full Text Available Historical perspectives on fisheries and related human behaviour provide valuable information on fishery resources and their exploitation, helping to more appropriately set management targets and determine relevant reference levels. In this study we analyse historical fisheries and fish trade at the north-eastern Baltic Sea coast in the late 17th century. Local consumption and export together amounted to the annual removal of about 200 tonnes of fish from the nearby sea and freshwater bodies. The fishery was very diverse and exploited altogether one cyclostome and 17 fish species with over 90% of the catch being consumed locally. The exported fish consisted almost entirely of high-valued species with Stockholm (Sweden being the most important export destination. Due to rich political history and natural features of the region, we suggest that the documented evidence of this small-scale fishery should be considered as the first quantitative summary of exploitation of aquatic living resources in the region and can provide a background for future analyses.

Atmospheric Forcing of the Winter Air–Sea Heat Fluxes over the Northern Red Sea

KAUST Repository

Papadopoulos, Vassilis P.; Abualnaja, Yasser; Josey, Simon A.; Bower, Amy; Raitsos, Dionysios E.; Kontoyiannis, Harilaos; Hoteit, Ibrahim

2013-01-01

The influence of the atmospheric circulation on the winter air–sea heat fluxes over the northern Red Sea is investigated during the period 1985–2011. The analysis based on daily heat flux values reveals that most of the net surface heat exchange variability depends on the behavior of the turbulent components of the surface flux (the sum of the latent and sensible heat). The large-scale composite sea level pressure (SLP) maps corresponding to turbulent flux minima and maxima show distinct atmospheric circulation patterns associated with each case. In general, extreme heat loss (with turbulent flux lower than −400 W m−2) over the northern Red Sea is observed when anticyclonic conditions prevail over an area extending from the Mediterranean Sea to eastern Asia along with a recession of the equatorial African lows system. Subcenters of high pressure associated with this pattern generate the required steep SLP gradient that enhances the wind magnitude and transfers cold and dry air masses from higher latitudes. Conversely, turbulent flux maxima (heat loss minimization with values from −100 to −50 W m−2) are associated with prevailing low pressures over the eastern Mediterranean and an extended equatorial African low that reaches the southern part of the Red Sea. In this case, a smooth SLP field over the northern Red Sea results in weak winds over the area that in turn reduce the surface heat loss. At the same time, southerlies blowing along the main axis of the Red Sea transfer warm and humid air northward, favoring heat flux maxima.

Atmospheric Forcing of the Winter Air–Sea Heat Fluxes over the Northern Red Sea

KAUST Repository

Papadopoulos, Vassilis P.

2013-03-01

The influence of the atmospheric circulation on the winter air–sea heat fluxes over the northern Red Sea is investigated during the period 1985–2011. The analysis based on daily heat flux values reveals that most of the net surface heat exchange variability depends on the behavior of the turbulent components of the surface flux (the sum of the latent and sensible heat). The large-scale composite sea level pressure (SLP) maps corresponding to turbulent flux minima and maxima show distinct atmospheric circulation patterns associated with each case. In general, extreme heat loss (with turbulent flux lower than −400 W m−2) over the northern Red Sea is observed when anticyclonic conditions prevail over an area extending from the Mediterranean Sea to eastern Asia along with a recession of the equatorial African lows system. Subcenters of high pressure associated with this pattern generate the required steep SLP gradient that enhances the wind magnitude and transfers cold and dry air masses from higher latitudes. Conversely, turbulent flux maxima (heat loss minimization with values from −100 to −50 W m−2) are associated with prevailing low pressures over the eastern Mediterranean and an extended equatorial African low that reaches the southern part of the Red Sea. In this case, a smooth SLP field over the northern Red Sea results in weak winds over the area that in turn reduce the surface heat loss. At the same time, southerlies blowing along the main axis of the Red Sea transfer warm and humid air northward, favoring heat flux maxima.

Geological evidence of tsunamis and earthquakes at the Eastern Hellenic Arc: correlation with historical seismicity in the eastern Mediterranean Sea

Directory of Open Access Journals (Sweden)

Gerassimos Papadopoulos

2012-12-01

Full Text Available Sedimentary stratigraphy determined by trenching in Dalaman, south-western Turkey, revealed three sand layers at a distance of approximately 240 m from the shoreline and at elevations of +0.30, +0.55 and +0.90 cm. Storm surge action does not explain the features of these deposits that show instead typical characteristics of tsunami deposition. The sand layers correlate with historical tsunamis generated by large earthquakes which ruptured the eastern Hellenic Arc and Trench in 1303, 1481 and 1741. Accelerator mass spectrometry 14C dating of a wood sample from layer II indicated deposition in AD 1473±46, which fits the 1481 event. From an estimated average alluvium deposition rate of approximately 0.13 cm/year, layers I and III were dated at 1322 and 1724, which may represent the large 1303 and 1741 tsunamis. The geological record of the 1303 key event is very poor; therefore, sand layer I perhaps represents an important geological signature of the 1303 tsunami. However, the strong tsunami reported to have been generated by the 1609 earthquake is missing from Dalaman stratigraphy: this underlines the sensitivity of tsunami geological signatures to various local factors. The 1303 earthquake ruptured the trench between the islands of Crete and Rhodes. For the earthquakes of 1481, 1609 and 1741 we suggested that they were very likely generated in the Rhodes Abyssal Plain where sea depths of up to approximately 4200 m, together with the thrust component of seismotectonics, favor tsunami generation. Sand dykes directed upwards from layer I to layer II indicated that the 1481 earthquake triggered liquefaction of sand layer I. The results substantially widen our knowledge about the historical earthquake and tsunami activity in the eastern Mediterranean basin.

Diversity, abundance and niche differentiation of ammonia-oxidizing prokaryotes in mud deposits of the eastern China marginal seas

Directory of Open Access Journals (Sweden)

Shaolan eYu

2016-02-01

Full Text Available The eastern China marginal seas are prominent examples of river-dominated ocean margins, whose most characteristic feature is the existence of isolated mud patches on sandy sediments. Ammonia-oxidizing prokaryotes play a crucial role in the nitrogen cycles of many marine environments, including marginal seas. However, few studies have attempted to address the distribution patterns of ammonia-oxidizing prokaryotes in mud deposits of these seas. The horizontal and vertical community composition and abundance of ammonia-oxidizing archaea (AOA and bacteria (AOB were investigated in mud deposits of the South Yellow Sea (SYS and the East China Sea (ECS by using amoA clone libraries and quantitative PCR. The diversity of AOB was comparable or higher in the mud zone of SYS and lower in ECS when compared with AOA. Vertically, surface sediments had generally higher diversity of AOA and AOB than middle and bottom layers. Diversity of AOA and AOB showed significant correlation with latitude. Nitrosopumilus and Nitrosospira lineages dominated AOA and AOB communities, respectively. Both AOA and AOB assemblages exhibited greater variations across different sites than those among various depths at one site. The abundance of bacterial amoA was generally higher than that of archaeal amoA, and both of them decreased with depth. Niche differentiation, which was affected by dissolved oxygen, salinity, ammonia and silicate (SiO32-, was observed between AOA and AOB and among different groups of them. The spatial distribution of AOA and AOB was significantly correlated with δ15NTN and SiO32-, and nitrate and δ13C, respectively. Both archaeal and bacterial amoA abundance correlated strongly with SiO32-. This study improves our understanding of spatial distribution of AOA and AOB in ecosystems featuring oceanic mud deposits.

Diversity, Abundance, and Niche Differentiation of Ammonia-Oxidizing Prokaryotes in Mud Deposits of the Eastern China Marginal Seas.

Science.gov (United States)

Yu, Shaolan; Yao, Peng; Liu, Jiwen; Zhao, Bin; Zhang, Guiling; Zhao, Meixun; Yu, Zhigang; Zhang, Xiao-Hua

2016-01-01

The eastern China marginal seas (ECMS) are prominent examples of river-dominated ocean margins, whose most characteristic feature is the existence of isolated mud patches on sandy sediments. Ammonia-oxidizing prokaryotes play a crucial role in the nitrogen cycles of many marine environments, including marginal seas. However, few studies have attempted to address the distribution patterns of ammonia-oxidizing prokaryotes in mud deposits of these seas. The horizontal and vertical community composition and abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) were investigated in mud deposits of the South Yellow Sea (SYS) and the East China Sea (ECS) by using amoA clone libraries and quantitative PCR. The diversity of AOB was comparable or higher in the mud zone of SYS and lower in ECS when compared with AOA. Vertically, surface sediments had generally higher diversity of AOA and AOB than middle and bottom layers. Diversity of AOA and AOB showed significant correlation with latitude. Nitrosopumilus and Nitrosospira lineages dominated AOA and AOB communities, respectively. Both AOA and AOB assemblages exhibited greater variations across different sites than those among various depths at one site. The abundance of bacterial amoA was generally higher than that of archaeal amoA, and both of them decreased with depth. Niche differentiation, which was affected by dissolved oxygen, salinity, ammonia, and silicate (SiO[Formula: see text]), was observed between AOA and AOB and among different groups of them. The spatial distribution of AOA and AOB was significantly correlated with δ(15)NTN and SiO[Formula: see text], and nitrate and δ(13)C, respectively. Both archaeal and bacterial amoA abundance correlated strongly with SiO[Formula: see text]. This study improves our understanding of spatial distribution of AOA and AOB in ecosystems featuring oceanic mud deposits.

Chemical Atmosphere-Snow-Sea Ice Interactions: defining future research in the field, lab and modeling

Science.gov (United States)

Frey, Markus

2015-04-01

The air-snow-sea ice system plays an important role in the global cycling of nitrogen, halogens, trace metals or carbon, including greenhouse gases (e.g. CO2 air-sea flux), and therefore influences also climate. Its impact on atmospheric composition is illustrated for example by dramatic ozone and mercury depletion events which occur within or close to the sea ice zone (SIZ) mostly during polar spring and are catalysed by halogens released from SIZ ice, snow or aerosol. Recent field campaigns in the high Arctic (e.g. BROMEX, OASIS) and Antarctic (Weddell sea cruises) highlight the importance of snow on sea ice as a chemical reservoir and reactor, even during polar night. However, many processes, participating chemical species and their interactions are still poorly understood and/or lack any representation in current models. Furthermore, recent lab studies provide a lot of detail on the chemical environment and processes but need to be integrated much better to improve our understanding of a rapidly changing natural environment. During a 3-day workshop held in Cambridge/UK in October 2013 more than 60 scientists from 15 countries who work on the physics, chemistry or biology of the atmosphere-snow-sea ice system discussed research status and challenges, which need to be addressed in the near future. In this presentation I will give a summary of the main research questions identified during this workshop as well as ways forward to answer them through a community-based interdisciplinary approach.

Diving into old age: muscular senescence in a large-bodied, long-lived mammal, the Weddell seal (Leptonychotes weddellii).

Science.gov (United States)

Hindle, Allyson G; Horning, Markus; Mellish, Jo-Ann E; Lawler, John M

2009-03-01

Classic aging theory postulates the absence of pronounced organismal senescence in wild animals since mortality probably occurs first. Large-bodied, long-lived mammals are a recognized exception to this tenet, yet organismal senescence has not been investigated to date in such mammals in the wild. Furthermore, oxidative stress theory of aging supports the suggestion that exercise hypoxia, as regularly incurred during apneustic foraging in diving mammals might lead to cellular dysfunction and accelerated aging. To determine if an aspect of organismal senescence occurs in wild marine mammals, we examined the pattern of skeletal muscle aging (contractile and connective tissue components of longissimus dorsi and pectoralis muscles) in free-ranging adult Weddell seals (9-26 years). The average myocyte cross-sectional area was 22% greater with age in the longissiums dorsi, but no significant increase occurred in the pectoralis. Cross-sectional area was not related to body mass. Changes in myocyte number per area were consistent with the 35-40% age-increase in extracellular space in both muscle groups. Also consistent with extracellular space remodeling, total and relative collagen contents were significantly elevated in older seals (115% in longissimus dorsi; 65% in pectoralis). The ratio of muscle myocyte to collagen declined with age (50-63%) at both sites. Additionally, a shift towards a higher ratio of type I to type III collagen occurred with advancing age in both muscle groups (79% increase in pectoralis; 49% in longissimus dorsi). We reject the classic tenet and null-hypothesis that Weddell seals do not survive to an age where muscular senescence becomes detectable.

Ongoing decline of shark populations in the Eastern Red Sea

KAUST Repository

Spaet, Julia L.Y.

2016-06-30

Information on the abundance and diversity of Red Sea elasmobranchs is notoriously scarce, even though sharks are among the most profitable fisheries of the region. Effective conservation would ideally entail baselines on pristine conditions, yet no such data is available for the Red Sea. To collect distribution and abundance data on Red Sea elasmobranchs, we conducted a dedicated longline and Baited Remote Underwater Video system (BRUVs) sampling program along the entire Red Sea coast of Saudi Arabia over the course of two years. Both survey techniques were opportunistically employed at central and southern Saudi Arabian (SA) Red Sea reef systems. In addition, BRUVs were employed in the northern SA Red Sea and at selected reef systems in Sudan. Shark catch per unit effort (CPUE) data for BRUVs and longline surveys were compared to published data from non-Red Sea reef systems. This comparison revealed CPUE estimates several orders of magnitude lower for both survey methods in the SA Red Sea compared to other reef systems around the world. Catch per unit effort values of BRUVs on Sudanese reefs on the contrary were within the range of estimates from various locations where sharks are considered common. We argue that decades of heavy fishing pressure on Red Sea marine resources has significantly altered the community structure of SA Red Sea reefs. There is an urgent need to establish effective management strategies for species of highest conservation concern. Our results have the potential to be used as a baseline, if such management strategies were to be established. © 2016 Elsevier Ltd

Natural and artificial radioactivity measurements in Eastern Black Sea region of Turkey

International Nuclear Information System (INIS)

Celik, N.; Cevik, U.; Celik, A.; Koz, B.

2009-01-01

In the present work, naturally occurring radionuclides of 226 Ra, 232 Th and 40 K were measured in soil samples collected from the Eastern Black Sea region of Turkey. It was found that the activity concentrations ranged from 12 to 120 Bq kg -1 for 226 Ra, from 13 to 121 Bq kg -1 for 232 Th and from 204 to 1295 Bq kg -1 for 40 K. Besides naturally occurring radionuclides, 137 Cs activity concentration was measured in soil, lichen and moss samples and it was found that 137 Cs activity concentration ranged from 27 to 775 Bq kg -1 with for soil, from 29 to 879 Bq kg -1 for lichen and from 67 to 1396 Bq kg -1 for moss samples. Annual effective doses due to the naturally occurring radionuclides and 137 Cs were estimated. Ecological half-lives of 137 Cs in lichen and moss species were estimated. The decrease of the activity concentrations in the present measurements (2007) relative to those in 1993 indicated ecological half-lives between 1.36 and 2.96 years for lichen and between 1.35 and 2.85 years for moss species

Miocene to recent tectonic and sedimentary evolution of the Anaximander Seamounts; eastern Mediterranean Sea

Science.gov (United States)

Cranshaw, Jennifer

This thesis is focused on the Messinian to Recent tectonic and sedimentary evolution of the Anaximander Mountains and surrounding environs in the eastern Mediterranean Sea. It is based on processing of high-resolution seismic reflection data and the interpretation and mapping of seismic reflection profiles collected from this area during the 2001 and 2007 research cruises. The data show that the greater Anaximander Mountains region experienced a short interval of tectonic quiescence during the Messinian when a thin evaporite unit was deposited across a major erosional surface. This phase of limited tectonic activity ended in the latest Miocene and was replaced by an erosional phase. Major unconformities in the area are interpreted to develop during the desiccation of the eastern Mediterranean associated with the so-called Messinian salinity crisis. During the early Pliocene, the region experienced an increase in tectonic activity, dominated by transpression. Small amounts of growth observed in Pliocene-Quaternary sediments suggested that the tectonic activity remained low during the early Pliocene-Quaternary. However, the extensive growth strata wedges developed in older sediments indicate a period of accelerated tectonic activity during the mid-late Pliocene-Quaternary. This study suggests that the Anaximander Mountain (sensu stricto ) and the Anaximenes Mountain developed during the Pliocene-Quaternary as the result of a crustal-scale thick-skinned linked imbricate thrust fan. The development of back thrusts in both mountains heightened the seafloor morphology of these submarine mountains and brought Eocene-Oligocene sediments into the core of these mountains. The Sim Erinc Plateau represents a 30-40 km wide transpressional fault zone developed during the Pliocene-Quaternary. In this region the corrugated seafloor morphology observed in the multibeam bathymetry map is the reflection of high-angle faults. It is speculated that this transpressional fault zone

Unlocking the hydrocarbon potential of the eastern Black Sea basin. Prospectivity of middle Miocene submarine fan reservoirs by seismic sequence stratigraphy

International Nuclear Information System (INIS)

Gundogan, Coskun; Galip, Ozbek; Ali, Demirer

2002-01-01

Full text : The objective of this paper is to present present depositional characteristics and hydrocarbon prospectivity of the middle Miocene submarine basin floor fan deposits from the exploration stand point of view by using seismic data available in the offshore eastern Black Sea basin. This basin is a Tertiary trough formed as a continuation of the Mesozoic oceanic basin. The hydrocarbon potential of the basin is believed to be high in the Tertiary section because of the existence of the elements necessary for generation, migration and entrapment of hydrocarbon. A sequence stratigraphic study has been carried out by using 2-d seismic data in the Turkish portion of the eastern Black Sea basin. The objective of the study was to determine periods of major clastic sediment influxes which might lead to identify good reservoir intervals and their spatial distribution in this basin. All basic seismic sequence stratigraphic interpretation techniques and seismic facies analysis were used to identify times of these sand rich deposition periods. Sequence stratigraphy and seismic facies analysis indicate that the basinal areas of the middle Miocene sequences were dominated mainly by submarine fan complexes introduced in the lowstand stages and pelagic sediments deposited during the transgressive and highstand stages. It was proposed that Turkish portion of this basin which is one of the best frontier exploration area with its high potential left in the world, is glimpsing to those looking for good future exploration opportunities.

Distribution of oxygen isotopes in the water masses of Drake Passage and the South Atlantic

Science.gov (United States)

Meredith, Michael P.; Grose, Katie E.; McDonagh, Elaine L.; Heywood, Karen J.; Frew, Russell D.; Dennis, Paul F.

1999-09-01

Measurements of the ratio of stable isotopes of oxygen (18O and 16O) from samples collected on World Ocean Circulation Experiment sections SR1b (eastern Drake Passage) and A11 (Punta Arenas to Cape Town) are used, together with hydrographic data, to deduce information about the formation and variability of South Atlantic and Southern Ocean water masses. The Drake Passage surface waters south of the Polar Front (PF) are isotopically light (δ18O around -0.4‰) owing to the influence of meteoric waters. The salinity and δ18O of the A11 surface waters yield an apparent freshwater end-member which is much isotopically lighter than the local precipitation, thus advection of these waters from farther south dominates over local effects in determining the surface water properties. The Drake Passage section shows unusual proximity of the two main fronts of the Antarctic Circumpolar Current (the PF and Subantarctic Front (SAF)), and we observe cold, fresh, and isotopically light water derived from the temperature-minimum Winter Water at the SAF. This water is of the correct density to freshen the intermediate water north of the SAF and thus play a role in the formation of the comparatively fresh Antarctic Intermediate Water (AAIW) of the South Atlantic. This confirms the role of Antarctic water in forming the South Atlantic variety of AAIW. Across the A11 section the oxygen isotope and salinity data at the AAIW core show very similar traces, with waters in the Malvinas Current loop showing lowest values of both. At the eastern boundary of the South Atlantic, the input of Red Sea Water from east of South Africa is observed via the presence of anomalously isotopically heavy AAIW. We deduce potentially significant temporal variability in the isotopic composition of Weddell Sea Deep Water (WSDW) by comparing the Drake Passage data to earlier data covering the outflow of the Weddell Sea. The A11 data show WSDW consistent with such variability, indicating that its effects could

Genetic signature of Last Glacial Maximum regional refugia in a circum-Antarctic sea spider

Science.gov (United States)

Soler-Membrives, Anna; Linse, Katrin; Miller, Karen J.; Arango, Claudia P.

2017-10-01

The evolutionary history of Antarctic organisms is becoming increasingly important to understand and manage population trajectories under rapid environmental change. The Antarctic sea spider Nymphon australe, with an apparently large population size compared with other sea spider species, is an ideal target to look for molecular signatures of past climatic events. We analysed mitochondrial DNA of specimens collected from the Antarctic continent and two Antarctic islands (AI) to infer past population processes and understand current genetic structure. Demographic history analyses suggest populations survived in refugia during the Last Glacial Maximum. The high genetic diversity found in the Antarctic Peninsula and East Antarctic (EA) seems related to multiple demographic contraction-expansion events associated with deep-sea refugia, while the low genetic diversity in the Weddell Sea points to a more recent expansion from a shelf refugium. We suggest the genetic structure of N. australe from AI reflects recent colonization from the continent. At a local level, EA populations reveal generally low genetic differentiation, geographically and bathymetrically, suggesting limited restrictions to dispersal. Results highlight regional differences in demographic histories and how these relate to the variation in intensity of glaciation-deglaciation events around Antarctica, critical for the study of local evolutionary processes. These are valuable data for understanding the remarkable success of Antarctic pycnogonids, and how environmental changes have shaped the evolution and diversification of Southern Ocean benthic biodiversity.

Viruses and Protists Induced-mortality of Prokaryotes around the Antarctic Peninsula during the Austral Summer.

Science.gov (United States)

Vaqué, Dolors; Boras, Julia A; Torrent-Llagostera, Francesc; Agustí, Susana; Arrieta, Jesús M; Lara, Elena; Castillo, Yaiza M; Duarte, Carlos M; Sala, Maria M

2017-01-01

During the Austral summer 2009 we studied three areas surrounding the Antarctic Peninsula: the Bellingshausen Sea, the Bransfield Strait and the Weddell Sea. We aimed to investigate, whether viruses or protists were the main agents inducing prokaryotic mortality rates, and the sensitivity to temperature of prokaryotic heterotrophic production and mortality based on the activation energy (Ea) for each process. Seawater samples were taken at seven depths (0.1-100 m) to quantify viruses, prokaryotes and protists abundances, and heterotrophic prokaryotic production (PHP). Viral lytic production, lysogeny, and mortality rates of prokaryotes due to viruses and protists were estimated at surface (0.1-1 m) and at the Deep Fluorescence Maximum (DFM, 12-55 m) at eight representative stations of the three areas. The average viral lytic production ranged from 1.0 ± 0.3 × 10 7 viruses ml -1 d -1 in the Bellingshausen Sea to1.3 ± 0.7 × 10 7 viruses ml -1 d -1 in the Bransfield Strait, while lysogeny, when detectable, recorded the lowest value in the Bellingshausen Sea (0.05 ± 0.05 × 10 7 viruses ml -1 d -1 ) and the highest in the Weddell Sea (4.3 ± 3.5 × 10 7 viruses ml -1 d -1 ). Average mortality rates due to viruses ranged from 9.7 ± 6.1 × 10 4 cells ml -1 d -1 in the Weddell Sea to 14.3 ± 4.0 × 10 4 cells ml -1 d -1 in the Bellingshausen Sea, and were higher than averaged grazing rates in the Weddell Sea (5.9 ± 1.1 × 10 4 cells ml -1 d -1 ) and in the Bellingshausen Sea (6.8 ± 0.9 × 10 4 cells ml -1 d -1 ). The highest impact on prokaryotes by viruses and main differences between viral and protists activities were observed in surface samples: 17.8 ± 6.8 × 10 4 cells ml -1 d -1 and 6.5 ± 3.9 × 10 4 cells ml -1 d -1 in the Weddell Sea; 22.1 ± 9.6 × 10 4 cells ml -1 d -1 and 11.6 ± 1.4 × 10 4 cells ml -1 d -1 in the Bransfield Strait; and 16.1 ± 5.7 × 10 4 cells ml -1 d -1 and 7.9 ± 2.6 × 10 4 cells ml -1 d -1 in the Bellingshausen Sea, respectively

Spring–summer albedo variations of Antarctic sea ice from 1982 to 2009

International Nuclear Information System (INIS)

Shao, Zhu-De; Ke, Chang-Qing

2015-01-01

This study examined the spring–summer (November, December, January and February) albedo averages and trends using a dataset consisting of 28 years of homogenized satellite data for the entire Antarctic sea ice region and for five longitudinal sectors around Antarctica: the Weddell Sea (WS), the Indian Ocean sector (IO), the Pacific Ocean sector (PO), the Ross Sea (RS) and the Bellingshausen–Amundsen Sea (BS). Time series data of the sea ice concentrations and sea surface temperatures were used to analyse their relations to the albedo. The results indicated that the sea ice albedo increased slightly during the study period, at a rate of 0.314% per decade, over the Antarctic sea ice region. The sea ice albedos in the PO, the IO and the WS increased at rates of 2.599% per decade (confidence level 99.86%), 0.824% per decade and 0.413% per decade, respectively, and the steepest increase occurred in the PO. However, the sea ice albedo in the BS decreased at a rate of −1.617% per decade (confidence level 95.05%) and was near zero in the RS. The spring–summer average albedo over the Antarctic sea ice region was 50.24%. The highest albedo values were mainly found on the continental coast and in the WS; in contrast, the lowest albedo values were found on the outer edge of the sea ice, the RS and the Amery Ice Shelf. The average albedo in the western Antarctic sea ice region was distinctly higher than that in the east. The albedo was significantly positively correlated with sea ice concentration (SIC) and was significantly negatively correlated with sea surface temperature (SST); these scenarios held true for all five longitudinal sectors. Spatially, the higher surface albedos follow the higher SICs and lower SST patterns. The increasing albedo means that Antarctic sea ice region reflects more solar radiation and absorbs less, leading to a decrease in temperature and much snowfall on sea ice, and further resulted in an increase in albedo. Conversely, the decreasing

Small scale variability of snow density on Antarctic sea ice

Science.gov (United States)

Wever, N.; Leonard, K. C.; Paul, S.; Jacobi, H. W.; Proksch, M.; Lehning, M.

2016-12-01

Snow on sea ice plays an important role in air-ice-sea interactions. For example, snow may smooth the ice surface when snow drift is occurring, while at the same time it may also generate roughness elements by interactions with the wind. Snow density is a key property in many processes, for example by influencing the thermal conductivity of the snow layer, radiative transfer inside the snow as well as the effects of aerodynamic forcing on the snowpack. We present data from an in-situ measurement campaign in the Weddell Sea during two subsequent cruises of RV Polarstern. By comparing snow density from snow pits and snow micro penetrometer (SMP) measurements, augmented by terrestrial laser scanning (TLS) on an area of 50x50 m2, highly resolved density profiles and surface topology were acquired at a horizontal resolution of approximately 30 cm. Average snow densities are about 280 kg/m3, but the analysis also reveals a high spatial variability in snow density on sea ice in both horizontal and vertical direction, ranging from roughly 170 to 360 kg/m3. This variability is expressed by coherent snow structures over several meters, which disappear over larger distances. A comparison with TLS data indicates that the spatial variability is related to deviations in surface topology. This suggests a strong influence from surface processes, for example wind, on the temporal development of density profiles. The fundamental relationship between density variations, surface roughness and changes therein as investigated in this study are interpreted with respect to larger-scale ice-movement and the ice mass balance.

Identification of new deep sea sinuous channels in the eastern Arabian Sea.

Science.gov (United States)

Mishra, Ravi; Pandey, D K; Ramesh, Prerna; Clift, Peter D

2016-01-01

Deep sea channel systems are recognized in most submarine fans worldwide as well as in the geological record. The Indus Fan is the second largest modern submarine fan, having a well-developed active canyon and deep sea channel system. Previous studies from the upper Indus Fan have reported several active channel systems. In the present study, deep sea channel systems were identified within the middle Indus Fan using high resolution multibeam bathymetric data. Prominent morphological features within the survey block include the Raman Seamount and Laxmi Ridge. The origin of the newly discovered channels in the middle fan has been inferred using medium resolution satellite bathymetry data. Interpretation of new data shows that the highly sinuous deep sea channel systems also extend to the east of Laxmi Ridge, as well as to the west of Laxmi Ridge, as previously reported. A decrease in sinuosity southward can be attributed to the morphological constraints imposed by the elevated features. These findings have significance in determining the pathways for active sediment transport systems, as well as their source characterization. The geometry suggests a series of punctuated avulsion events leading to the present array of disconnected channels. Such channels have affected the Laxmi Basin since the Pliocene and are responsible for reworking older fan sediments, resulting in loss of the original erosional signature supplied from the river mouth. This implies that distal fan sediments have experienced significant signal shredding and may not represent the erosion and weathering conditions within the onshore basin at the time of sedimentation.

Ensemble-based evaluation of extreme water levels for the eastern Baltic Sea

Science.gov (United States)

Eelsalu, Maris; Soomere, Tarmo

2016-04-01

The risks and damages associated with coastal flooding that are naturally associated with an increase in the magnitude of extreme storm surges are one of the largest concerns of countries with extensive low-lying nearshore areas. The relevant risks are even more contrast for semi-enclosed water bodies such as the Baltic Sea where subtidal (weekly-scale) variations in the water volume of the sea substantially contribute to the water level and lead to large spreading of projections of future extreme water levels. We explore the options for using large ensembles of projections to more reliably evaluate return periods of extreme water levels. Single projections of the ensemble are constructed by means of fitting several sets of block maxima with various extreme value distributions. The ensemble is based on two simulated data sets produced in the Swedish Meteorological and Hydrological Institute. A hindcast by the Rossby Centre Ocean model is sampled with a resolution of 6 h and a similar hindcast by the circulation model NEMO with a resolution of 1 h. As the annual maxima of water levels in the Baltic Sea are not always uncorrelated, we employ maxima for calendar years and for stormy seasons. As the shape parameter of the Generalised Extreme Value distribution changes its sign and substantially varies in magnitude along the eastern coast of the Baltic Sea, the use of a single distribution for the entire coast is inappropriate. The ensemble involves projections based on the Generalised Extreme Value, Gumbel and Weibull distributions. The parameters of these distributions are evaluated using three different ways: maximum likelihood method and method of moments based on both biased and unbiased estimates. The total number of projections in the ensemble is 40. As some of the resulting estimates contain limited additional information, the members of pairs of projections that are highly correlated are assigned weights 0.6. A comparison of the ensemble-based projection of

Retrospective analysis of seasonal ocean growth rates of two sea winter Atlantic Salmon in eastern Maine using historic scales

Science.gov (United States)

Izzo, Lisa K.; Zydlewski, Joseph D.

2017-01-01

Substantial declines of anadromous Atlantic Salmon Salmo salar have occurred throughout its range, with many populations at the southern extent of the distribution currently extirpated or endangered. While both one sea winter (1SW) and two sea winter (2SW) spawner numbers for the North American stocks have declined since the 1950s, the decline has been most severe in 2SW spawners. The first months at sea are considered a period of high mortality. However, early ocean mortality alone cannot explain the more pronounced decline of 2SW spawners, suggesting that the second year at sea may be more critical than previously thought. Atlantic Salmon scales collected by anglers and the state agency from 1946 to 2013 from five rivers in eastern Maine were used to estimate smolt age and ocean age of returning adults. Additionally, seasonal growth rates of maiden 2SW spawners were estimated using intercirculi measurements and linear back-calculation methods. Generalized linear mixed models (Gaussian family, log link function) were used to investigate the influence of average sea surface temperature, accumulated thermal units, the Atlantic Multidecadal Oscillation (AMO) and North Atlantic Oscillation indices, smolt age, smolt length, postsmolt growth, and river of origin on growth rate during the oceanic migration of North American Atlantic Salmon. Results suggest that different factors influence salmon growth throughout their oceanic migration, and previous growth can be a strong predictor of future size. Growth was negatively impacted by the phase of the AMO, which has been linked to salmon abundance trends, in early spring following the postsmolt period. This is likely when the 1SW and 2SW stock components separate, and our results suggest that this period may be of interest in future work examining the disproportionate decline in 2SW spawners.

Circulation, retention, and mixing of waters within the Weddell-Scotia Confluence, Southern Ocean: The role of stratified Taylor columns

Science.gov (United States)

Meredith, Michael P.; Meijers, Andrew S.; Naveira Garabato, Alberto C.; Brown, Peter J.; Venables, Hugh J.; Abrahamsen, E. Povl; Jullion, Loïc.; Messias, Marie-José

2015-01-01

The waters of the Weddell-Scotia Confluence (WSC) lie above the rugged topography of the South Scotia Ridge in the Southern Ocean. Meridional exchanges across the WSC transfer water and tracers between the Antarctic Circumpolar Current (ACC) to the north and the subpolar Weddell Gyre to the south. Here, we examine the role of topographic interactions in mediating these exchanges, and in modifying the waters transferred. A case study is presented using data from a free-drifting, intermediate-depth float, which circulated anticyclonically over Discovery Bank on the South Scotia Ridge for close to 4 years. Dimensional analysis indicates that the local conditions are conducive to the formation of Taylor columns. Contemporaneous ship-derived transient tracer data enable estimation of the rate of isopycnal mixing associated with this column, with values of O(1000 m2/s) obtained. Although necessarily coarse, this is of the same order as the rate of isopycnal mixing induced by transient mesoscale eddies within the ACC. A picture emerges of the Taylor column acting as a slow, steady blender, retaining the waters in the vicinity of the WSC for lengthy periods during which they can be subject to significant modification. A full regional float data set, bathymetric data, and a Southern Ocean state estimate are used to identify other potential sites for Taylor column formation. We find that they are likely to be sufficiently widespread to exert a significant influence on water mass modification and meridional fluxes across the southern edge of the ACC in this sector of the Southern Ocean.

A model study of the seasonality of sea surface temperature and circulation in the Atlantic North-Eastern Tropical Upwelling System.

Directory of Open Access Journals (Sweden)

Saliou eFaye

2015-09-01

Full Text Available The climatological seasonal cycle of the sea surface temperature (SST in the north-eastern tropical Atlantic (7-25°N, 26-12°W is studied using a mixed layer heat budget in a regional ocean general circulation model. The region, which experiences one of the larger SST cycle in the tropics, forms the main part of the Guinea Gyre. It is characterized by a seasonally varying open ocean and coastal upwelling system, driven by the movements of the intertropical convergence zone (ITCZ. The model annual mean heat budget has two regimes schematically. South of roughly 12°N, advection of equatorial waters, mostly warm, and warming by vertical mixing, is balanced by net air-sea flux. In the rest of the domain, a cooling by vertical mixing, reinforced by advection at the coast, is balanced by the air-sea fluxes. Regarding the seasonal cycle, within a narrow continental band, in zonal mean, the SST early decrease (from September, depending on latitude, until December is driven by upwelling dynamics off Senegal and Mauritania (15°-20°N, and instead by air-sea fluxes north and south of these latitudes. Paradoxically, the later peaks of upwelling intensity (from March to July, with increasing latitude essentially damp the warming phase, driven by air-sea fluxes. The open ocean cycle to the west, is entirely driven by the seasonal net air-sea fluxes. The oceanic processes significantly oppose it, but for winter north of ~18°N. Vertical mixing in summer-autumn tends to cool (warm the surface north (south of the ITCZ, and advective cooling or warming by the geostrophic Guinea Gyre currents and the Ekman drift. This analysis supports previous findings on the importance of air-sea fluxes offshore. It mainly offers quantitative elements on the modulation of the SST seasonal cycle by the ocean circulation, and particularly by the upwelling dynamics.Keywords: SST, upwelling, circulation, heat budget, observations, modeling

Climatology of sea breezes along the Red Sea coast of Saudi Arabia

KAUST Repository

Khan, Basit

2018-04-25

Long-term near-surface observations from five coastal stations, high-resolution model data from Modern Era Retrospective-Analysis for Research and Applications (MERRA) and high-resolution daily sea surface temperature (SST) from National Ocean and Atmospheric Administration (NOAA) are used to investigate the climatology of sea breezes over the eastern side of the Red Sea region. Results show existence of separate sea breeze systems along different segments of the Red Sea coastline. Based on the physical character and synoptic influences, sea breezes in the Red Sea are broadly divided into three regions: the north and the middle Red Sea (NMRS), the Red Sea convergence zone (RSCZ) and the southern Red Sea (SRS) regions. On average, sea breezes developed on 67% of days of the 10-year study period. Although sea breezes occur almost all year, this mesoscale phenomenon is most frequent from May to October (78% of the total sea breeze days). The sea breeze frequency increases from north to south (equatorwards), and sea breeze characteristics appear to vary both temporally and spatially. In addition to land-sea thermal differential, coastline shape, latitude and topography, the prevailing northwesterly at NMRS region, the convergence of northwesterly and southeasterly wind system at RSCZ region and the northeast and southwest monsoon at SRS region play an important role in defining the sea breeze characteristics over the Red Sea.

Sea surface temperature mapping using a thermal infrared scanner

Digital Repository Service at National Institute of Oceanography (India)

RameshKumar, M.R; Pandya, R; Mathur, K.M.; Charyulu, R; Rao, L.V.G.

1 metre water column below the sea surface. A thermal infrared scanner developed by the Space Applications Centre (ISRO), Ahmedabad was operated on board R.V. Gaveshani in April/May 1984 for mapping SST over the eastern Arabian Sea. SST values...

Early Cretaceous paleomagnetic results from Marie Byrd Land, West Antarctica: Implications for the Weddellia collage of crustal blocks

Science.gov (United States)

Divenere, Vic; Kent, Dennis V.; Dalziel, Ian W. D.

1995-05-01

A new approximately 117 Ma paleomagnetic pole has been defined from the study of volcanic and plutonic rocks from the eastern portion Marie Byrd Land (MBL). The new pole (185.6 deg E/56.8 deg S, A(sub 95) = 8.7 deg) implies that the eastern portion of MBL was an integral part of Weddellia, which included the ancestral Antarctic Peninsula, Thurston Island, and Ellsworth-Whitmore Mountains blocks of West Antarctica. This pole is generally similar to a approximately 125 Ma pole from Thurston Island. Both poles call for major clockwise rotation and poleward motion of eastern MBL and Thurston Island between the Early Cretaceous (125-117 Ma) and the mid-Cretaceous (110-100 Ma). We propose that in the Early Cretaceous, eastern MBL and the Eastern Province of New Zealand were part of a continuous active Pacific margin of Gondwana, connecting with the Antarctic Peninsula, and distinct from western MBL, the Western Province of New Zealand, and North Victoria Land. These western terranes are thought to have accreted to Gondwana in the Devonian. Eastern MBL and the Eastern Province of New Zealand amalgamated with western MBL and the Western Province of New Zealand by the mid-Cretaceous. Major Early Cretaceous motions of the Weddellia blocks postdate the estimated initiation of seafloor spreading in the Weddell Sea and therefore may be the result of plate reorganization during the Cretaceous Quiet Zone.

Multichannel seismic-reflection data collected in 1980 in the eastern Chukchi Sea

Science.gov (United States)

Grantz, Arthur; Mann, Dennis M.; May, Steven D.

1986-01-01

The U.S. Geological Survey (USGS) collected approximately 2,652 km of 24-channel seismic-reflection data in early September, 1980, over the continental shelf in the eastern Chukchi Sea (Fig. 1). The profiles were collected on the USGS Research Vessel S.P. Lee. The seismic energy source consisted of a tuned array of five airguns with a total volume of 1213 cubic inches of air compressed to approximately 1900 psi. The recording system consisted of a 24-channel, 2400 meter long streamer with a group interval of 100 m, and a GUS (Global Universal Science) model 4200 digital recording instrument. Shots were fired every 50 meters. Navigational control for the survey was provided by a Magnavox integrated navigation system using transit satellites and doppler-sonar augmented by Loran C (Rho-Rho). A 2-millisecond sampling rate was used in the field; the data were later desampled to 4-milliseconds during the demultiplexing process. 8 seconds data length was recorded. Processing was done at the USGS Pacific Marine Geology Multichannel Processing Center in Menlo Park, California, in the sequence: editing-demultiplexing, velocity analysis, CDP stacking, deconvolution-filtering, and plotting on an electrostatic plotter. Plate 1 is a trackline chart showing shotpoint navigation.

Interannual Variability in Weddell Sea Ice Formation and Bottom Water Outflow in Response to the Antarctic Circumpolar Wave

Science.gov (United States)

Drinkwater, M.; Kreyscher, M.

1997-01-01

The seasonal sea-ice cover surrounding the continent of Antarctica, together with the circumpolar current belt, form a contiguous pathway for propagation and transfer of climatological anomalies around the Sourthern hemisphere.

Ice Draft and Ice Velocity Data in the Beaufort Sea, 1990-2003

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set provides measurement of sea ice draft (m) and the movement of sea ice (cm/s) over the continental shelf of the Eastern Beaufort Sea. The data set spans...

Tracers confirm downward mixing of Tyrrhenian Sea upper waters associated with the Eastern Mediterranean Transient

Directory of Open Access Journals (Sweden)

W. Roether

2011-01-01

Full Text Available Observations of tritium and ³He in the Tyrrhenian Sea, 1987–2009, confirm the enhanced vertical mixing of intermediate waters into the deep waters that has been noted and associated with the Eastern Mediterranean Transient in previous studies. Our evidence for the mixing rests on increasing tracer concentrations in the Tyrrhenian deep waters, accompanied by decreases in the upper waters, which are supplied from the Eastern Mediterranean. The downward transfer is particularly evident between 1987 and 1997. Later on, information partly rests on increasing tritium-³He ages; here we correct the observed ³He for contributions released from the ocean floor. The Tyrrhenian tracer distributions are fully compatible with data upstream of the Sicily Strait and in the Western Mediterranean. The tracer data show that mixing reached to the bottom and confirm a cyclonic nature of the deep water circulation in the Tyrrhenian. They furthermore indicate that horizontal homogenization of the deep waters occurs on a time scale of roughly 5 years. Various features point to a reduced impact of Western Mediterranean Deep Water (WMDW in the Tyrrhenian during the enhanced-mixing period. This is an important finding because it implies less upward mixing of WMDW, which has been named a major process to enable the WMDW to leave the Mediterranean via the Gibraltar Strait. On the other hand, the TDW outflow for several years represented a major influx of enhanced salinity and density waters into the deep-water range of the Western Mediterranean.

Sympagic occurrence of Eusirid and Lysianassoid amphipods under Antarctic pack ice

NARCIS (Netherlands)

Krapp, Rupert H.; Berge, Jorgen; Flores, Hauke; Gulliksen, Bjorn; Werner, Iris

2008-01-01

During three Antarctic expeditions (2004, ANT XXI-4 and XXII-2; 2006, ANT XXIII-6) with the German research icebreaker R/V Polarstern, six different amphipod species were recorded under the pack ice of the Weddell Sea and the Lazarev Sea. These cruises covered Austral autumn (April), summer

Ciguatoxin-like substances in edible fish on the eastern Mediterranean.

Science.gov (United States)

Bentur, Yedidia; Spanier, Ehud

2007-09-01

The consumption of edible fish (e.g., Siganus spp) was assumed to have caused ciguatera poisoning at an atypical site, the eastern Mediterranean. This pilot study assesses the presence of ciguatoxin-like substances in edible fish on the eastern Mediterranean coast of Israel. Samples of Siganus rivulatus from polluted seawater (Haifa Bay), Siganus rivulatus from relatively clean seawater (Dor), and fish from the freshwater Sea of Galilee not inhabited by toxic algae were analyzed during summertime. Ciguatoxin-like substances were tested by a membrane immunobead assay that yields a color reaction (positive, weakly positive, negative). Significantly more large and small fish from Haifa Bay yielded positive color reactions compared to fish from Dor. Sea of Galilee fish gave no positive color reactions. Our results suggest the presence of ciguatoxin-like substances in edible fish of the eastern Mediterranean. Additional analyses are needed to determine whether these substances are ciguatoxins or related polyethers.

Thick massive gas hydrate deposits were revealed by LWD in Off-Joetsu area, eastern margin of Japan Sea.

Science.gov (United States)

Tanahashi, M.; Morita, S.; Matsumoto, R.

2016-12-01

GR14 and HR15 survey cruises, which were dedicated to the LWD (Logging While Drilling), were carried out in summers of 2014 and 2015, respectively, by Meiji University and Geological Survey of Japan, AIST to explore the "gas chimney" structures in eastern margin of Japan Sea. Shallow (33 to 172m-bsf, average 136m-bsf) 33 LWD drilling were performed in Oki Trough, Off-Joetsu, and Mogami Trough areas along eastern margin of Japan Sea during two cruises. Schlumberger LWD tools, GeoVISION (resistivity), TeleScope, ProVISION (NMR) and SonicVISION were used during GR14. NeoScope (neutron) was added and SonicScope was replaced for SonicVISION during HR14. The data quality was generally good. "Gas chimney" structures with acoustic blanking columns on the high frequency seismic sections with mound and pockmark morphologic features on the sea bottom, are well developed within survey areas. Every LWD records taken from gas chimney structures during the cruises show high resistivity and acoustic velocity anomalies which suggest the development of gas hydrate. Characteristic development of massive gas hydrate was interpreted at the Umitaka CW mound structure, Off-Joetsu. The mound lies at 890-910m in water depth and has very rough bottom surface, regional high resistivity, regional high heat flow, several natural seep sites, 200m x 300m area, and 10-20m height. 8 LWD holes, J18L to J21L and J23L to J26L, were drilled on and around the mound. There are highly anomalous intervals which suggest the development of massive gas hydrate at J24L, with high resistivity, high Vp and Vs, high neutron porosity, low natural gamma ray intensity, low neutron gamma density, low NMR porosity, low NMR permeability, low formation sigma, from 10 to 110m-bsf with intercalating some thin less hydrate layers. It is interpreted that there is several tens of meter thick massive gas hydrate in the gas chimney mound. It is partly confirmed by the later nearby coring result which showed the repetition of

Sedimentary sources and processes in the eastern Arabian Sea: Insights from environmental magnetism, geochemistry and clay mineralogy

Directory of Open Access Journals (Sweden)

Kumar Avinash

2016-03-01

Full Text Available The spatial distribution patterns of surficial sediment samples from different sedimentary domains (shallow to deep-sea regions of the eastern Arabian Sea were studied using sediment proxies viz. environmental magnetism, geochemistry, particle size and clay mineralogy. Higher concentrations of magnetic minerals (high χlf were recorded in the deep-water sediments when compared with the shallow water sediments. The magnetic mineralogy of one of the shallow water samples is influenced by the presence of bacterial magnetite as evidenced from the χARM/χlf vs. χARM/χfd biplot. However, the other samples are catchment-derived. The high correlation documented for χlf, anhysteretic remanent magnetisation (χARM and isothermal remanent magnetisation (IRM with Al indicates that the deep-sea surficial sediments are influenced by terrigenous fluxes which have been probably derived from the southern Indian rivers, the Sindhu (the Indus and the Narmada-Tapti rivers. A lower Mn concentration is recorded in the upper slope sediments from the oxygen minimum zone (OMZ but a higher Mn/Al ratio is documented in the lower slope and deep-sea sediments. Clay minerals such as illite (24–48.5%, chlorite (14.1–34.9%, smectite (10.6–28.7% and kaolinite (11.9–27.5% dominate the sediments of shallow and deep-sea regions and may have been derived from different sources and transported by fluvial and aeolian agents. Organic carbon (OC data indicate a low concentration in the shallow/shelf region (well oxygenated water conditions and deeper basins (increased bottom-water oxygen concentration and low sedimentation rate. High OC concentrations were documented in the OMZ (very low bottom-water oxygen concentration with high sedimentation rate. The calcium carbonate concentration of the surface sediments from the continental shelf and slope regions (<1800 m up to the Chagos-Laccadive Ridge show higher concentrations (average = 58% when compared to deep basin

Reconstruction and outlook of the radionuclide transport in the Mediterranean seas chain

International Nuclear Information System (INIS)

Maderich, M.

1999-01-01

A set of models was developed to reconstruct and predict in 1960-2010 the 137 Cs contamination in the system of Mediterranean seas that was result of the testing of nuclear weapons and the Chernobyl accident. It incorporates the submodels of the Black Sea, Azov Sea, Marmara Sea, Western and Eastern Mediterranean

Change in the intensity of low-salinity water inflow from the Bay of Bengal into the Eastern Arabian Sea from the Last Glacial Maximum to the Holocene: Implications for monsoon variations

Digital Repository Service at National Institute of Oceanography (India)

Mahesh, B.S.; Banakar, V.K.

A 100–400 km wide region of the coastal Eastern Arabian Sea (EAS), off the west-coast of India, is characterized by a low-salinity tongue formed by the inflow of low-salinity surface water from the Bay of Bengal (BoB). This low-salinity tongue...

Discovering where bluefin tuna, Thunnus thynnus, might go: using environmental and fishery data to map potential tuna habitat in the eastern Mediterranean Sea

OpenAIRE

Dimitrios Damalas; Persefoni Megalofonou

2012-01-01

Based on a dataset derived from commercial fisheries in the eastern Mediterranean Sea in 1998-2005, we applied generalized additive models (GAMs) to investigate the relative influence of a range of environmental factors on catch rates of Atlantic bluefin tuna (Thunnus thynnus Linnaeus, 1785). GAM analyses were conducted by separately modelling (1) the probability of making a catch (encountering a school), and (2) the positive catch rates (school size). Results suggested intra-annual variation...

Evaluation of genetic diversity of cultivated tea clones (Camellia sinensis (L. Kuntze in the eastern black sea coast by inter-simple sequence repeats (ISSRS

Directory of Open Access Journals (Sweden)

Beris Fatih S.

2016-01-01

Full Text Available Tea is the most globally consumed drink after spring water and an important breeding plant with high economical value in Turkey. In half a century, various kinds of tea cultivars have been bred in Turkey to improve the quality and yield of tea plants. Since tea reproduces sexually, tea fields vary in quality. Thus, determining the genetic diversity and relationship of the plants to support breeding and cultivation is important. In this study we aimed to determine the genetic diversity of tea cultivars breeding in the Eastern Black Sea coast of Turkey and the genetic relationship between them, to verify whether the qualitative morphological designations of the clones are genetically true by the ISSR markers. Herein, the genetic diversity and relationships of 18 Turkish tea cultivars were determined using 15 ISSR markers with sizes ranging from 250 to 3000 base pairs. The similarity indices among these cultivars were between 0.456 and 0.743. Based on cluster analysis using UPGMA, some of tea cultivars originating from the same geographical position were found to be clustered closely. Our data provide valuable information and a useful basis to assist selection and cloning experiments of tea cultivars and also help farmers to find elite parental clones for tea breeding in the Eastern Black Sea coast of Turkey.

Behaviour of nickel, copper, zinc and cadmium in the upper 300 m of a transect in the Southern Ocean (57°-62°S, 49°W)

NARCIS (Netherlands)

Nolting, R.F.; Baar, H.J.W. de

1994-01-01

The distributions of Ni, Cu, Zn and Cd in relation to phosphate, nitrate and silicate in the upper 300 m of a transect in the Southern Ocean were studied. This transect covers the Scotia Sea, the Confluence and the Weddell Sea. These three watermasses are clearly separated by their temperature and

Effect of Ocean Interannual Variability on Acoustic Propagation in the Philippine Sea and South China Sea

Science.gov (United States)

2017-06-01

depth in order to analyze the Deep Water (Figure 12). The maximum values are found in the Philippine Sea, eastern part of the Mindanao Island in May...the water column stability. The seasonal variability is modulated by interannual and decadal modes of variability. The same effects were found ...ABSTRACT (maximum 200 words ) Effect of interannual variability of temperature and salinity on acoustic propagation in the Philippine Sea and South

The Satellite Passive-Microwave Record of Sea Ice in the Ross Sea Since Late 1978

Science.gov (United States)

Parkinson, Claire L.

2009-01-01

the highest rate of increase in sea ice coverage of any of five standard divisions of the Southern Ocean, although the Weddell Sea, Indian Ocean, and Western Pacific Ocean all also had sea ice increases, while only the Bellingshausen/Smundsen Seas experienced overall sea ice decreases. Overall, the Southern Ocean sea ice cover increased at an average rate of 10,800 plus or minus 2,500 square kilometers per year between November 1978 and December 2007, with every month showing positive values although with some of these values not being statistically significant. The sea ice increase since November 1978 was preceded by a sharp decrease in Southern Ocean ice coverage in the 1970's and is in marked contrast to the decrease in Arctic sea ice coverage that has occurred both in the period since November 1978 and since earlier in the 1970's. On a yearly average bases, for 1979-2007 the Southern Ocean sea ice extent increased at a rate of 1.0 plus or minus 0.4% per decade, whereas the Arctic ice extent decreased at the much greater rate of 4.0 plus or minus 0.4 percent per decade (closer to the % per decade rate of increase in the Ross Sea). Considerable research is ongoing to explain the differences.

Phytoplankton and pigment patterns across frontal zones in the Atlantic sector of the Southern Ocean

NARCIS (Netherlands)

van Leeuwe, Maria A.; Kattner, Gerhard; van Oijen, Tim; de Jong, Jeroen T. M.; de Baar, Hein J.W.

2015-01-01

Phytoplankton distribution and concentrations of macronutrients and iron were studied in the Polar Frontal Zone (PFZ) and the eastern Weddell Gyre of the Southern Ocean, during austral autumn. HPLC analysis of algal pigments was combined with microscopy observations to assess algal distribution.

Biogeochemical Cycling and Sea Ice Dynamics in the Bering Sea across the Mid-Pleistocene Transition

Science.gov (United States)

Detlef, H.; Sosdian, S. M.; Belt, S. T.; Smik, L.; Lear, C. H.; Hall, I. R.; Kender, S.; Leng, M. J.; Husum, K.; Cabedo-Sanz, P.

2017-12-01

Today the Bering Sea is characterized by high primary productivity (PP) along the eastern shelf, maintained by CO2 and nutrient rich upwelled deep waters and nutrient release during spring sea ice melting. As such, low oxygen concentrations are pervasive in mid-depth waters. Changes in ventilation and export productivity in the past have been shown to impact this oxygen minimum zone. On glacial/interglacial (G/IG) timescales sea ice formation plays a pivotal role on intermediate water ventilation with evidence pointing to the formation of North Pacific Intermediate Water (NPIW) in the Bering Sea during Pleistocene glacial intervals. In addition, sea ice plays a significant role in both long- and short-term climate change via associated feedback mechanisms. Thus, records of sea ice dynamics and biogeochemical cycling in the Bering Sea are necessary to fully understand the interaction between PP, circulation patterns, and past G/IG climates with potential implications for the North Pacific carbon cycle. Here we use a multi-proxy approach to study sea ice dynamics and bottom water oxygenation, across three intervals prior to, across, and after the Mid-Pleistocene Transition (MPT, 1.2-0.7 Ma) from International Ocean Discovery Program Site U1343. The MPT, most likely driven by internal climate mechanisms, is ideal to study changes in sea ice dynamics and sedimentary redox conditions on orbital timescales and to investigate the implications for associated feedback mechanisms. The sea ice record, based on various biomarkers, including IP25, shows substantial increase in sea ice extent across the MPT and the occurrence of a late-glacial/deglacial sea ice spike, with consequences for glacial NPIW formation and land glacier retreat via the temperature-precipitation feedback. U/Mn of foraminiferal authigenic coatings, a novel proxy for bottom water oxygenation, also shows distinct variability on G/IG timescales across the MPT, most likely a result of PP and water mass

Rock-block configuration in Uppland and the Aalands-hav basin, the regional surroundings of the SKB site in Forsmark, Sea and land areas, eastern Sweden

Energy Technology Data Exchange (ETDEWEB)

Beckholmen, Monica; Tiren, Sven A. (GEOSIGMA AB (Sweden))

2010-12-15

The Forsmark SKB site lies at the west-northwest trending shoreline in northern Uppland, sheltered from the sea by one of the larger islands in the Uppland archipelago, Graesoe. To assess the structures around Forsmark also in the sea area, the bottom structures of the Aalands-hav basin were investigated by means of depth readings from sea charts. Two rock-block maps with rock blocks at different scales were constructed and analysed for their top surface elevation. The topography in Uppland is more broken in the sea area east and northeast of Forsmark than it is on land. The major structure in the Aalands-hav basin is a westnorth- westerly line that passes southwest of Aaland, with a very steep gradient from the Aaland archipelago down to an exceptionally low sea-floor valley. On its southern side it rises in steps to a low flat basin divided into a deeper western half and a somewhat shallower eastern half. The deep west-north-westerly zone can be traced on-land past Oeregrund and Forsmark. West of Oeregrund however, the main trough swings into a north-northwesterly direction, just west of Graesoe. The southern border south of Oeregrund and Forsmark, shows a major drop in elevation northern side down. Forsmark thus lies on a ribbon with lower ground on both its southern and northern boundaries. This west-north-westerly belt is cut in two by a major north-south lineament that cuts through the archipelago between Aaland and Graesoe with a very deep canyon. This structure was seismically active in June 2006. The southern part of this line constitutes the western border of the low basin and has a steep gradient on its western side up to the Uppland mainland. The deep basin is filled with Jotnian metasediments. South of this basin, the Uppland mainland continues under water towards the east. South of Aaland an east-north-easterly ridge separates the low basin to the north from an east-west trending trough which is the eastern continuation of a major onland structure

Rock-block configuration in Uppland and the Aalands-hav basin, the regional surroundings of the SKB site in Forsmark, Sea and land areas, eastern Sweden

International Nuclear Information System (INIS)

Beckholmen, Monica; Tiren, Sven A.

2010-12-01

The Forsmark SKB site lies at the west-northwest trending shoreline in northern Uppland, sheltered from the sea by one of the larger islands in the Uppland archipelago, Graesoe. To assess the structures around Forsmark also in the sea area, the bottom structures of the Aalands-hav basin were investigated by means of depth readings from sea charts. Two rock-block maps with rock blocks at different scales were constructed and analysed for their top surface elevation. The topography in Uppland is more broken in the sea area east and northeast of Forsmark than it is on land. The major structure in the Aalands-hav basin is a westnorth- westerly line that passes southwest of Aaland, with a very steep gradient from the Aaland archipelago down to an exceptionally low sea-floor valley. On its southern side it rises in steps to a low flat basin divided into a deeper western half and a somewhat shallower eastern half. The deep west-north-westerly zone can be traced on-land past Oeregrund and Forsmark. West of Oeregrund however, the main trough swings into a north-northwesterly direction, just west of Graesoe. The southern border south of Oeregrund and Forsmark, shows a major drop in elevation northern side down. Forsmark thus lies on a ribbon with lower ground on both its southern and northern boundaries. This west-north-westerly belt is cut in two by a major north-south lineament that cuts through the archipelago between Aaland and Graesoe with a very deep canyon. This structure was seismically active in June 2006. The southern part of this line constitutes the western border of the low basin and has a steep gradient on its western side up to the Uppland mainland. The deep basin is filled with Jotnian metasediments. South of this basin, the Uppland mainland continues under water towards the east. South of Aaland an east-north-easterly ridge separates the low basin to the north from an east-west trending trough which is the eastern continuation of a major onland structure

Ice Draft and Ice Velocity Data in the Beaufort Sea, 1990-2003, Version 1

Data.gov (United States)

National Aeronautics and Space Administration — This data set provides measurement of sea ice draft (m) and the movement of sea ice (cm/s) over the continental shelf of the Eastern Beaufort Sea. The data set spans...

50 CFR 223.202 - Steller sea lion.

Science.gov (United States)

2010-10-01

... kilometers) or within sight of the eastern shore of Marmot Island, including the Steller sea lion rookery... sites. Listed Steller sea lion rookery sites consist of the rookeries in the Aleutian Islands and the... 16540 SE corner. 8. Pinnacle Rock 54°46.0 N 161°46.0 W 16540 Whole island. 9. Clubbing Rks (N) 54°43.0 N...

Paleotsunamis in Eastern Taiwan

Science.gov (United States)

Yen, Jiun-Yee; Yu, Neng-Ti; Hirakawa, Kazuomi; Chyi, Shyh-Jeng; Huang, Shao-Yi

2017-04-01

Although Taiwan is located in the active collision zone between Eurasian and the Philippine Sea plate with very high seismicity in and surrounding the island, and supposedly highly susceptible to tsunami hazard. However, there is no record of tsunami hazard in the past one hundred years, and only very few historical records show some possible extreme event occurred. Therefore study of tsunami was scarce in Taiwan. Although historical records do show possible tsunami events, the records were too sparse and incomplete to confidently reconstruct the paleotsunami events. In the past few years, numerical simulations based on possible tsunami-genic zones near Taiwan show that the island could be affected by the correctly directed tsunami. Nevertheless, there is no detail, scientific research of paleotsunami records yet in Taiwan. Our field survey in eastern Taiwan (facing the western Pacific Ocean) along the coast uncovered several outcrops contain gravels embedded in well-developed soil layers. The rounded meta-sandstone gravels are clearly beach-origin and were brought to their current location upon extreme wave events, which is composed of either volcanic-clastic deposits from nearby hills or organic soil layers formed locally. Our investigation indicates that there are at least 3 events in the northern half of eastern Taiwan and at least 2 events in southern part of eastern Taiwan. Although these outcrops are next to the shoreline and Taiwan is susceptible from typhoons, these gravels could be farther away from the beach at the time of their deposition due to current high retreat rate of the sea cliff. Further investigations are needed to delineate possible sources of tsunamis that caused the deposits.

Movement Ecology of the Reef Manta Ray Manta alfredi in the Eastern Red Sea

KAUST Repository

Braun, Camrin D.

2013-07-01

Many well-studied elasmobranch populations have recently exhibited significant decline. The limited data related to fisheries and sightings for many unstudied or poorly understood populations indicate that these are also suffering. Directed fisheries and more cryptic threats such as entanglement and vessel strike represent significant risk to mobulid rays, arguably one of the most vulnerable elasmobranch groups. Very little information currently exists describing the basic ecology of manta rays or quantifying anthropogenic threats and impacts; however, recent efforts have drastically improved the body of knowledge available for these species, including oceanographic influences on movement, seasonal migration, and mating behaviors. Nevertheless, Red Sea mantas remain completely enigmatic. In this thesis, Chapter 1 details results from tagging 18 reef manta rays Manta alfredi in the eastern Red Sea using satellite and acoustic tag technology and demonstrates that mantas occupy areas with high human traffic. The combined satellite and acoustic techniques define both regional movements and ‘hotspots’ of habitat use where there is significant potential for manta-human interaction. I also present opportunistic sighting data that corroborate anthropogenic impacts on this population. Chapter 2 explores the vertical component of the nine satellite tags that were deployed on Manta alfredi as described in the previous chapter. Seven tags returned adequate data for analysis. Three of the seven were physically recovered yielding full archival datasets of depth, temperature, and light levels every 10-15 seconds for over 2.6 5 million cumulative data points. Mantas frequented the upper 10 m during the day and occupied deeper water through nocturnal periods. Individuals also exhibited deep diving behavior as deep as 432 m, extending the known depth range of the species. An investigation of 76 high-resolution deep dives suggests gliding is a significant behavioral component of

Assessment of big floods in the Eastern Black Sea Basin of Turkey.

Science.gov (United States)

Yüksek, Ömer; Kankal, Murat; Üçüncü, Osman

2013-01-01

In this study, general knowledge and some details of the floods in Eastern Black Sea Basin of Turkey are presented. Brief hydro-meteorological analysis of selected nine floods and detailed analysis of the greatest flood are given. In the studied area, 51 big floods have taken place between 1955-2005 years, causing 258 deaths and nearly US $500,000,000 of damage. Most of the floods have occurred in June, July and August. It is concluded that especially for the rainstorms that have caused significantly damages, the return periods of the rainfall heights and resultant flood discharges have gone up to 250 and 500 years, respectively. A general agreement is observed between the return periods of rains and resultant floods. It is concluded that there has been no significant climate change to cause increases in flood harms. The most important human factors to increase the damage are determined as wrong and illegal land use, deforestation and wrong urbanization and settlement, psychological and technical factors. Some structural and non-structural measures to mitigate flood damages are also included in the paper. Structural measures include dykes and flood levees. Main non-structural measures include flood warning system, modification of land use, watershed management and improvement, flood insurance, organization of flood management studies, coordination between related institutions and education of the people and informing of the stakeholders.

Drought reconstruction in eastern Hulun Buir steppe, China and its linkages to the sea surface temperatures in the Pacific Ocean

Science.gov (United States)

Liu, Na; Liu, Yu; Bao, Guang; Bao, Ming; Wang, Yanchao; Zhang, Lizhi; Ge, Yuxiang; Bao, Wurigen; Tian, Heng

2016-01-01

A tree-ring width chronology covering the period 1780-2013 AD was developed from Pinus sylvestris var. mongolica for the eastern Hulun Buir steppe, a region located on the edge of the eastern Mongolian Plateau, China. Climate-growth response analysis revealed drought stress to be the primary limiting factor for tree growth. Therefore, the mean February-July standardized precipitation evapotranspiration index (SPEI) was reconstructed over the period 1819-2013, where the reconstruction could account for 32.8% of the variance in the instrumental record over the calibration period 1953-2011. Comparison with other tree-ring-based moisture sequences from nearby areas confirmed a high degree of confidence in our reconstruction. Severe drought intervals since the late 1970s in our study area consisted with the weakening East Asian summer monsoon, which modulating regional moisture conditions in semi-arid zone over northern China. Drought variations in the study area significantly correlated with sea surface temperatures (SSTs) in North Pacific Ocean, suggesting a possible connection of regional hydroclimatic variations to the Pacific Decadal Oscillation (PDO). The potential influence associated with El Niño-Southern Oscillation (ENSO) was primarily analyzed.

Fisheries management responses to climate change in the Baltic Sea

DEFF Research Database (Denmark)

Thøgersen, Thomas Talund; Hoff, Ayoe; Frost, Hans S.

2015-01-01

The long term management plan for cod in the eastern Baltic Sea was introduced in 2007 to ensure the full reproductive capacity of cod and an economically viable fishing industry. If these goals are to be fulfilled under changing environmental conditions, a readjustment of the current management ...... scenarios in which the economic consequences of different management objectives for the fishing fleets are assessed through a dynamic multi-species and multi-fleet bio-economic assessment model that include both species interactions and climate change....... plan may be needed. Therefore, this paper investigates the economic impacts of managing the cod, sprat and herring stocks in the eastern Baltic Sea, given on-going climate change, which is known to affect cod recruitment negatively. It is shown that climate change may have severe biological......The long term management plan for cod in the eastern Baltic Sea was introduced in 2007 to ensure the full reproductive capacity of cod and an economically viable fishing industry. If these goals are to be fulfilled under changing environmental conditions, a readjustment of the current management...

Lead pollution and its sources along the Turkish coast of the Black Sea

Directory of Open Access Journals (Sweden)

M. UNSAL

2001-12-01

Full Text Available Lead pollution and its sources have been investigated in the south-eastern and south-western Black Sea. Surficial sediments and mussels were collected in different seasons of the year from the south-eastern and south-western Black Sea and analysed for their lead contents. In the south-eastern Black Sea sediments from the easternmost and from the central stations contained the highest lead concentrations. Sediments contained 8 to 10 times the lead concentrations of sediments from the south-west. Samples taken from rivers, streams and effluents had especially high lead concentrations. The highest lead concentrations were found in sediments collected in October and December. Lead concentrations in mussels from the south-eastern coast were comparatively lower compared to those from the south-western coast. The highest average values occurred in December and in October. In the south-western Black Sea, the highest lead concentrations in sediments were obtained in those from Inebolu, followed by those from around Zonguldak. The concentrations increased from the middle to the west of the southern Black Sea coast, possibly due to the effect of the Danube River. Sediments taken in September had the highest lead concentrations, followed by samples taken in December. Very high lead concentrations (> 10 μ g g-1 were observed in mussels from those stations where the sediments also contained high concentrations. Mussels had their highest lead concentrations in January and April.

The Amino Acid Composition of Blue Swimming Crab (Portunus Segnis, Forskal, 1775 from The North Eastern Mediterranean Sea of Turkey

Directory of Open Access Journals (Sweden)

Engin Artar

2018-04-01

Full Text Available This study was carried out to detect the content of amino acid in female and male specimens of blue swimming crab (Portunus segnis obtained from (including 12 male crab and also 12 female crab North Eastern Mediterranean Sea, Turkey. The protein was identified as 17.63% and 18.13% for female and male crab respevtively. Totally 9 essential amino acids were recorded in the present study. Lysine and leucine constituted the highest essential amino acid (EAA concentrations in P. segnis. This species was found to be in good score in terms of the level of EAA and the EAA/Non-EAA ratios when compared with other economical crab species.

Rationale for restocking the Eastern Baltic cod stock

DEFF Research Database (Denmark)

Støttrup, Josianne; Overton, Julia Lynne; Paulsen, Helge

2008-01-01

The Danish Institute for Fisheries Research and Bornholm's Salmon Hatchery examined the potential for restocking Baltic cod (Gadus morhua callarias L.) in the eastern Baltic Sea. This cod population has adapted to the unique brackish water conditions where successful spawning depends on regular i...

Photophysiology and cellular composition of sea ice algae

International Nuclear Information System (INIS)

Lizotte, M.P.

1989-01-01

The productivity of sea ice algae depends on their physiological capabilities and the environmental conditions within various microhabitats. Pack ice is the dominant form of sea ice, but the photosynthetic activity of associated algae has rarely been studied. Biomass and photosynthetic rates of ice algae of the Weddell-Scotia Sea were investigated during autumn and winter, the period when ice cover grows from its minimum to maximum. Biomass-specific photosynthetic rates typically ranged from 0.3 to 3.0 μg C · μg chl -1 · h -1 higher than land-fast ice algae but similar to Antarctic phytoplankton. Primary production in the pack ice during winter may be minor compared to annual phytoplankton production, but could represent a vital seasonal contribution to the Antarctic ecosystem. Nutrient supply may limit the productivity of ice algae. In McMurdo Sound, congelation ice algae appeared to be more nutrient deficient than underlying platelet ice algae based on: lower nitrogen:carbon, chlorophyll:carbon, and protein:carbohydrate; and 14 C-photosynthate distribution to proteins and phospholipids was lower, while distribution to polysaccharides and neutral lipids was higher. Depletion of nitrate led to decreased nitrogen:carbon, chlorophyll:carbon, protein:carbohydrate, and 14 C-photosynthate to proteins. Studied were conducted during the spring bloom; therefore, nutrient limitation may only apply to dense ice algal communities. Growth limiting conditions may be alleviated when algae are released into seawater during the seasonal recession of the ice cover. To continue growth, algae must adapt to the variable light field encountered in a mixed water column. Photoadaptation was studied in surface ice communities and in bottom ice communities

A STUDY ON THE HENDIADYOINS IN THE EASTERN BLACK-SEA REGION DIALECTS / ORTA VE DOĞU KARADENIZ AĞIZLARINDA GÖRÜLEN IKILEMELER ÜZERINE BIR DEĞERLENDIRME

Directory of Open Access Journals (Sweden)

Dr. Ercan ALKAYA

2008-08-01

Full Text Available In this study, the hendiadyoins of the dialects of the Central andEastern Black-Sea Region such as Ordu, Giresun, Rize and Trabzon whichcan be observed as non-literary usages are dealt with. The hendiadyoins takenfrom the dialect studies on the afore-mentioned dialects and from theDerleme Sözlüğü are assessed in respect with their origins, structures andmeanings.

Bacterial community composition in different sediments from the Eastern Mediterranean Sea: a comparison of four 16S ribosomal DNA clone libraries.

Science.gov (United States)

Polymenakou, Paraskevi N; Bertilsson, Stefan; Tselepides, Anastasios; Stephanou, Euripides G

2005-10-01

The regional variability of sediment bacterial community composition and diversity was studied by comparative analysis of four large 16S ribosomal DNA (rDNA) clone libraries from sediments in different regions of the Eastern Mediterranean Sea (Thermaikos Gulf, Cretan Sea, and South lonian Sea). Amplified rDNA restriction analysis of 664 clones from the libraries indicate that the rDNA richness and evenness was high: for example, a near-1:1 relationship among screened clones and number of unique restriction patterns when up to 190 clones were screened for each library. Phylogenetic analysis of 207 bacterial 16S rDNA sequences from the sediment libraries demonstrated that Gamma-, Delta-, and Alphaproteobacteria, Holophaga/Acidobacteria, Planctomycetales, Actinobacteria, Bacteroidetes, and Verrucomicrobia were represented in all four libraries. A few clones also grouped with the Betaproteobacteria, Nitrospirae, Spirochaetales, Chlamydiae, Firmicutes, and candidate division OPl 1. The abundance of sequences affiliated with Gammaproteobacteria was higher in libraries from shallow sediments in the Thermaikos Gulf (30 m) and the Cretan Sea (100 m) compared to the deeper South Ionian station (2790 m). Most sequences in the four sediment libraries clustered with uncultured 16S rDNA phylotypes from marine habitats, and many of the closest matches were clones from hydrocarbon seeps, benzene-mineralizing consortia, sulfate reducers, sulk oxidizers, and ammonia oxidizers. LIBSHUFF statistics of 16S rDNA gene sequences from the four libraries revealed major differences, indicating either a very high richness in the sediment bacterial communities or considerable variability in bacterial community composition among regions, or both.

Seasonal and spatial variations of marine litter on the south-eastern Black Sea coast.

Science.gov (United States)

Terzi, Yahya; Seyhan, Kadir

2017-07-15

The south-eastern Black Sea coast in Turkey was evaluated for marine litter composition and density covering nine beaches during four seasons. The marine litter (>2cm in size), was collected from the coast and categorized into material and usage categories. The data analysis showed that plastic was the most abundant litter (≥61.65%) by count and weight followed by styrofoam and fabric. The marine litter density ranged from 0.03 to 0.58 with a mean (±SD) of 0.16±0.02 items/m 2 by count. Based on weight, it varied between 0.44 and 14.74g/m 2 with 3.35±1.63. The east side had a higher marine litter density than the west side with significant differences between beaches. The variations due to different seasons were not significant for any beach. The results of this study should provide baseline information about the coastal marine pollution and will assist the mitigation strategies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enrichment of Bacteria From Eastern Mediterranean Sea Involved in Lignin Degradation via the Phenylacetyl-CoA Pathway

Directory of Open Access Journals (Sweden)

Hannah L. Woo

2018-05-01

Full Text Available The degradation of allochthonous terrestrial organic matter, such as recalcitrant lignin and hemicellulose from plants, occurs in the ocean. We hypothesize that bacteria instead of white-rot fungi, the model organisms of aerobic lignin degradation within terrestrial environments, are responsible for lignin degradation in the ocean due to the ocean’s oligotrophy and hypersalinity. Warm oxic seawater from the Eastern Mediterranean Sea was enriched on lignin in laboratory microcosms. Lignin mineralization rates by the lignin-adapted consortia improved after two sequential incubations. Shotgun metagenomic sequencing detected a higher abundance of aromatic compound degradation genes in response to lignin, particularly phenylacetyl-CoA, which may be an effective strategy for marine microbes in fluctuating oxygen concentrations. 16S rRNA gene amplicon sequencing detected a higher abundance of Gammaproteobacteria and Alphaproteobacteria bacteria such as taxonomic families Idiomarinaceae, Alcanivoraceae, and Alteromonadaceae in response to lignin. Meanwhile, fungal Ascomycetes and Basidiomycetes remained at very low abundance. Our findings demonstrate the significant potential of bacteria and microbes utilizing the phenylacetyl-CoA pathway to contribute to lignin degradation in the Eastern Mediterranean where environmental conditions are unfavorable for fungi. Exploring the diversity of bacterial lignin degraders may provide important enzymes for lignin conversion in industry. Enzymes may be key in breaking down high molecular weight lignin and enabling industry to use it as a low-cost and sustainable feedstock for biofuels or other higher-value products.

Relationship of spontaneous pneumothorax cases seen in Eastern Black Sea region with meteorological changes

Science.gov (United States)

Yamac, Mustafa Esat; Karapolat, Sami; Turkyilmaz, Atila; Seyis, Kubra Nur; Tekinbas, Celal

2017-08-01

The relationship of climate changes or weather conditions with the incidence of pneumothorax has been explored for many years. We aimed at revealing the effects of meteorological changes on the incidence of pneumothorax in the Eastern Black Sea region where spontaneous pneumothorax cases are seen relatively more frequently. The records of 195 subjects (179 males and 16 females) who had been monitored and treated due to spontaneous pneumothorax between January 2006 and December 2012 at our clinic were reviewed retrospectively, and their relationship was investigated with the meteorological data obtained by going through the database archive records of the 11th Regional Meteorology Directorate for the years between 2006 and 2012. Wind velocity was observed to be less in the days of having spontaneous pneumothorax than in the days of having no spontaneous pneumothorax, and the difference was found statistically significant ( P = 0.026). The people of our region whose active lifestyle is reflected in their working life, social life, and even in their folk dances usually take a rest in the days of slower wind speed. We think that this state of resting leads to an increase in the frequency of spontaneous pneumothorax.

Skill Testing a Three-Dimensional Global Tide Model to Historical Current Meter Records

Science.gov (United States)

2013-12-17

breaking internal gravity waves generated over rough topography. The strength of the globally averaged wave drag is tuned to minimize the RMS...Ross Sea SO 02 39 83 Drake Passage SO 03 15 30 Weddell Sea SO 04 45 127 Antarctic Circumpolar Current SP 01 19 49 East Auckland Current SP 02 28 75 East

Cetacean line-transect survey conducted in the eastern Bering Sea shelf by Alaska Fisheries Science Center, National Marine Mammal Laboratory from NOAA Ship Miller Freeman from 1999-07-07 to 2004-06-30 (NCEI Accession 0131862)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Visual surveys for cetaceans were conducted on the eastern Bering Sea shelf along transect lines, in association with the AFSC’s echo integration trawl surveys for...

A comparison of the physics of the northern and southern shelves of the eastern Bering Sea and some implications for the ecosystem

Science.gov (United States)

Stabeno, Phyllis J.; Farley, Edward V., Jr.; Kachel, Nancy B.; Moore, Sue; Mordy, Calvin W.; Napp, Jeffrey M.; Overland, James E.; Pinchuk, Alexei I.; Sigler, Michael F.

2012-06-01

Sufficient oceanographic measurements have been made in recent years to describe the latitudinal variation in the physics of the eastern Bering Sea shelf and the potential impact of climate change on the species assemblages in the two ecosystems (north and south). Many of the predicted ecosystem changes will result from alterations in the timing and extent of sea ice. It is predicted that the sea ice in the northern Bering Sea will be less common in May, but will continue to be extensive through April. In contrast, the southern shelf will have, on average, much less sea ice than currently observed, but with large interannual and multiyear variability until at least 2050. Thus, even under current climate warming scenarios, bottom temperatures on the northern shelf will remain cold. Based on biophysical measurements, the southern and northern ecosystems were divided by a North-South Transition at ˜60°N. The northern middle shelf was characterized by a freshwater lens at the surface, cold bottom temperatures, and a thicker pycnocline than found on the southern shelf. Subsurface phytoplankton blooms were common. In contrast, the southern shelf stratification was largely determined by temperature alone; the pycnocline was thin (oftenstomias, respectively) are unlikely to become common in the north. The projected warming of the southern shelf will limit the distribution of arctic species (e.g., snow crab, Chionoecetes opilio) to the northern shelf and will likely permit expansion of subarctic species into the southern Bering Sea. The distribution and abundance of baleen whales will respond to shifts in prey availability; for instance, if prey are advected northward from the southeastern Bering Sea, an extension of range and an increase in seasonally migratory baleen whale numbers is anticipated. Thus, alteration of this ecosystem in response to climate change is expected to result in something other than a simple northward shift in the distribution of all species.

Coupled sea surface temperature-seawater delta O-18 reconstructions in the Arabian Sea at the millennial scale for the last 35 ka

NARCIS (Netherlands)

Anand, P.; Kroon, D.; Singh, A.D.; Ganssen, G.M.

2008-01-01

Two sediment cores from the western (905; 10.46°9′N, 51.56°4′E, water depth 1586 m) and eastern (SK17; 15°15′N, 72°58′E, water depth 840 m) Arabian Sea were used to study past sea surface temperatures (SST) and seawater δ

Extending the Instrumental Record of Sea-Level Change: A 1300-Year Sea-Level Record From Eastern Connecticut

Science.gov (United States)

Donnelly, J. P.; Cleary, P.

2002-12-01

The instrumental record of sea-level change in the northeastern United States extends back to the early 20th century and at New York City (NYC) extends back to 1856. These tide gauge records indicate that sea level has risen at a rate of 2.5 to 4 mm/year over the last 100-150 years. Geologic evidence of sea-level change in the region over the last 2,000 years indicates rates of sea-level rise of about 1 mm/year or less. The discordance between the instrumental and geologic records is frequently cited as potentially providing evidence that anthropogenic warming of the climate system has resulted in an increase in the rate of sea-level rise. In order to begin to test the hypothesis that acceleration in the rate of sea-level rise has occurred in the last 150 years due to anthropogenic climate warming, accurate and precise information on the timing of the apparent acceleration in sea-level rise are needed. Here we construct a high-resolution relative sea-level record for the past 1350 years by dating basal salt marsh peat samples above a glacial erratic in a western Connecticut salt marsh. Preservation of marsh vegetation remains in the sediment record that has a narrow vertical habitat range at the upper end of the tidal range provides information on past sea levels. { \\it Spartina patens} (marsh hay) and { \\it Juncus gerardi} (black rush) dominate both the modern marsh and their remains are the major constituent of the marsh sediments and occur in the modern marsh between mean high water (MHW) and mean highest high water. We use the elevation distribution of modern plant communities to estimate the relationship of sediment samples to paleo-mean high water. The chronology is based on 15 radiocarbon ages, supplemented by age estimates derived from the horizons of industrial Pb pollution and pollen indicative of European land clearance. Thirteen of the radiocarbon ages and the Pb and pollen data come from samples taken along a contact between marsh peat and a glacial

Predicting the impacts of Mississippi River diversions and sea-level rise on spatial patterns of eastern oyster growth rate and production

Science.gov (United States)

Wang, Hongqing; Chen, Qin; La Peyre, Megan K.; Hu, Kelin; La Peyre, Jerome F.

2017-01-01

There remains much debate regarding the perceived tradeoffs of using freshwater and sediment diversions for coastal restoration in terms of balancing the need for wetland restoration versus preserving eastern oyster (Crassostrea virginica) production. Further complicating the issue, climate change-induced sea-level rise (SLR) and land subsidence are also expected to affect estuarine water quality. In this study, we developed a process-based numerical modeling system that couples hydrodynamic, water quality, and oyster population dynamics. We selected Breton Sound Estuary (BSE) (∼2740 km2) in the eastern Mississippi River Deltaic Plain since it is home to several of the largest public oyster seed grounds and private leases for the Gulf coast. The coupled oyster population model was calibrated and validated against field observed oyster growth data. We predicted the responses of oyster population in BSE to small- (142 m3 s−1) and large-scale (7080 m3 s−1) river diversions at the Caernarvon Freshwater Diversion structure planned in the 2012 Coastal Master Plan (Louisiana) under low (0.38 m) and high (1.44 m) relative sea-level rise (RSLR = eustatic SLR + subsidence) compared to a baseline condition (Year 2009). Model results showed that the large-scale diversion had a stronger negative impact on oyster population dynamics via freshening of the entire estuary, resulting in reduced oyster growth rate and production than RSLR. Under the large-scale diversion, areas with optimal oyster growth rates (>15 mg ash-free dry weight (AFDW) oyster−1 wk−1) and production (>500 g AFDW m−2 yr−1) would shift seaward to the southeastern edge of the estuary, turning the estuary into a very low oyster production system. RSLR however played a greater role than the small-scale diversion on the magnitude and spatial pattern of oyster growth rate and production. RSLR would result in an overall estuary-wide decrease in oyster growth rate and production as a

Preserved Crevasse Casts in the Whales Deep Basin, eastern Ross Sea

Science.gov (United States)

Bart, P. J.; Tulaczyk, S. M.

2017-12-01

A recent seismic stratigraphic study showed that the large bathymetric saddle in the Whales Deep Basin in eastern Ross Sea is a compound grounding zone wedge (CGZW). The basin was occupied by the paleo Bindschadler Ice Stream when grounded ice advanced to the outer continental shelf during the last glacial maximum (LGM). The CGZW is composed of at least seven overlapping GZWs. The crest of the bathymetric saddle corresponds to the grounding zone of GZW7, i.e., the seventh GZW. The north face of the saddle is essentially equivalent to the GZW7 foreset and the south side of the saddle is the GZW7 topset, i.e., the seafloor surface to which the paleo Bindschadler Ice Stream was grounded. The GZW7 topset is mantled by a series of relatively small-amplitude, but very long, ridges with low sinuosity. These ridges were previously imaged by Mosola and Anderson (2006). Here we show a larger-area multibeam survey that was acquired in 2015 during expedition NBP1502B. The larger-area multibeam survey shows that the ridges have amplitudes ranging from 2 to 11 m above grade and have an overall northeast-southwest orientation over an area of at least 500 km2 on the central and western flank of Whales Deep Basin middle continental shelf in water depths ranging from 500 to 550 m. The ridges have spacing that mostly range between 1 and 2 km. The longest ridges are observed to be 40 km. The ridges in the center of the trough have flatter tops than those in the shallower water on the flank of Houtz Bank. In our ongoing investigation of these interesting features, we hypothesize that the ridges formed below a rapidly flowing ice stream as it thinned and was decoupling from the bed towards the end of GZW7 deposition. High ice deformation rates accompanying this process caused the development of large basal crevasses or ice shelf rifts that reached the seafloor. Subglacial till was scraped and collected into lower parts of these crevasses/rifts. Chronologic data indicates that these

New techniques on oil spill modelling applied in the Eastern Mediterranean sea

Science.gov (United States)

Zodiatis, George; Kokinou, Eleni; Alves, Tiago; Lardner, Robin

2016-04-01

Small or large oil spills resulting from accidents on oil and gas platforms or due to the maritime traffic comprise a major environmental threat for all marine and coastal systems, and they are responsible for huge economic losses concerning the human infrastructures and the tourism. This work aims at presenting the integration of oil-spill model, bathymetric, meteorological, oceanographic, geomorphological and geological data to assess the impact of oil spills in maritime regions such as bays, as well as in the open sea, carried out in the Eastern Mediterranean Sea within the frame of NEREIDs, MEDESS-4MS and RAOP-Med EU projects. The MEDSLIK oil spill predictions are successfully combined with bathymetric analyses, the shoreline susceptibility and hazard mapping to predict the oil slick trajectories and the extend of the coastal areas affected. Based on MEDSLIK results, oil spill spreading and dispersion scenarios are produced both for non-mitigated and mitigated oil spills. MEDSLIK model considers three response combating methods of floating oil spills: a) mechanical recovery using skimmers or similar mechanisms; b) destruction by fire, c) use of dispersants or other bio-chemical means and deployment of booms. Shoreline susceptibility map can be compiled for the study areas based on the Environmental Susceptibility Index. The ESI classification considers a range of values between 1 and 9, with level 1 (ESI 1) representing areas of low susceptibility, impermeable to oil spilt during accidents, such as linear shorelines with rocky cliffs. In contrast, ESI 9 shores are highly vulnerable, and often coincide with natural reserves and special protected areas. Additionally, hazard maps of the maritime and coastal areas, possibly exposed to the danger on an oil spill, evaluate and categorize the hazard in levels from low to very high. This is important because a) Prior to an oil spill accident, hazard and shoreline susceptibility maps are made available to design

Is there a distinct continental slope fauna in the Antarctic?

Science.gov (United States)

Kaiser, Stefanie; Griffiths, Huw J.; Barnes, David K. A.; Brandão, Simone N.; Brandt, Angelika; O'Brien, Philip E.

2011-02-01

The Antarctic continental slope spans the depths from the shelf break (usually between 500 and 1000 m) to ˜3000 m, is very steep, overlain by 'warm' (2-2.5 °C) Circumpolar Deep Water (CDW), and life there is poorly studied. This study investigates whether life on Antarctica's continental slope is essentially an extension of the shelf or the abyssal fauna, a transition zone between these or clearly distinct in its own right. Using data from several cruises to the Weddell Sea and Scotia Sea, including the ANDEEP (ANtarctic benthic DEEP-sea biodiversity, colonisation history and recent community patterns) I-III, BIOPEARL (BIOdiversity, Phylogeny, Evolution and Adaptive Radiation of Life in Antarctica) 1 and EASIZ (Ecology of the Antarctic Sea Ice Zone) II cruises as well as current databases (SOMBASE, SCAR-MarBIN), four different taxa were selected (i.e. cheilostome bryozoans, isopod and ostracod crustaceans and echinoid echinoderms) and two areas, the Weddell Sea and the Scotia Sea, to examine faunal composition, richness and affinities. The answer has important ramifications to the link between physical oceanography and ecology, and the potential of the slope to act as a refuge and resupply zone to the shelf during glaciations. Benthic samples were collected using Agassiz trawl, epibenthic sledge and Rauschert sled. By bathymetric definition, these data suggest that despite eurybathy in some of the groups examined and apparent similarity of physical conditions in the Antarctic, the shelf, slope and abyssal faunas were clearly separated in the Weddell Sea. However, no such separation of faunas was apparent in the Scotia Sea (except in echinoids). Using a geomorphological definition of the slope, shelf-slope-abyss similarity only changed significantly in the bryozoans. Our results did not support the presence of a homogenous and unique Antarctic slope fauna despite a high number of species being restricted to the slope. However, it remains the case that there may be

Distribution of metals and extent of contamination in sediments from the south-eastern Baltic Sea (Lithuanian zone

Directory of Open Access Journals (Sweden)

Nijolė Remeikaitė-Nikienė

2018-04-01

Full Text Available Summary: The distribution of metals (Pb, Cu, Cd, Ni, Cr, Zn in surface sediments and the potential pollution sources in the south-eastern part (SE of the Baltic Sea (Lithuanian zone were investigated in relation to the environmental characteristics (amount of fine-grained particles, TOC content in sediments, origin of sedimentary organic matter, salinity, water depth in 2011–2014. The higher metal concentrations were measured in sediments of the Curonian Lagoon and in the open waters. An approach using various environmental indices (enrichment factor EF, geoaccumulation index Igeo and contamination factor CF was used to quantitatively assess a contamination degree. The principal component analysis (PCA was applied in order to further scrutinize pollution from metal sources. The values of the contamination indices showed no/very low sediment contamination with Ni and Cr, minor–moderate contamination with Cu, Zn and Pb and moderate–considerable pollution with Cd. The strong relationships among metals suggested their similar distribution pattern and a combination of natural and anthropogenic sources. The higher metal concentrations coincided with an increasing amount of fine-grained fraction and organic carbon. In the territorial waters, the distribution of elements was related to the water depth. In addition, the binding of metals with insoluble iron sulphides might explain their high concentrations at the most remote and deepest stations. Keywords: Metals, Enrichment factor, Geoaccumulation index, Contamination factor, The Baltic Sea, The Curonian Lagoon

Trace metal concentrations in marine organisms from the Eastern Aegean, Turkey

International Nuclear Information System (INIS)

Kucuksezgin, F.

1999-01-01

Monitoring of mercury, cadmium and lead levels in striped mullet (Mullus barbatus) was conducted in the Eastern Aegean over 3 year period and in some other species during 1996 in the framework of a National Marine Measurement Program and MED-POL II Project for the Aegean Sea. Of all the research on the concentrations of trace metals in the Aegean environment only a little has been carried out in that part of the Eastern Aegean

Changes in distributional patterns of plaice Pleuronectes platessa in the central and eastern North Sea; do declining nutrient loadings play a role?

Science.gov (United States)

Støttrup, Josianne G.; Munk, Peter; Kodama, Masashi; Stedmon, Colin

2017-09-01

Since the beginning of the 1990s, there has been a change in the relative distribution of smaller age-classes of plaice Pleuronectes platessa (age 1-3) in the North Sea. The abundances have increased in deeper, more offshore areas, while coastal abundances have been stagnant or declining. For the same time period available time series data on nutrient conditions in the coastal North Sea area show that the freshwater nitrogen loading has decreased by about 50%. While nutrient concentrations in the ambient environment have been shown to influence growth in juvenile plaice through influence on their prey, we here inspect the potential linkage between distributional changes in plaice and the decline in nutrient loading. We compare plaice observations in coastal areas in the eastern North Sea, which have experienced large changes in eutrophication, with observations for the Dogger Bank, a large sandbank in a shallow offshore area of the North Sea. The Dogger Bank, was used as a reference location assuming this area has been less influenced from coastal eutrophication but similar regional climate conditions, and here we found no changes in the abundances of juvenile plaice. The increase in the use of offshore habitats as nursery areas by juvenile plaice in the North Sea appears not related to water depth per se but driven by specific processes dominating in near-shore areas and may be related to changes in nutrient loadings. This point to the importance of separating more general depth-related factors from conditions specific for near-shore areas, such as nutrient loadings in coastal waters and export offshore. The concurrent changes in environment and in distribution of juvenile plaice may have implications for environmental and fisheries management.

76 FR 46279 - Marine Mammals; File No. 87-1851

Science.gov (United States)

2011-08-02

..., NMFS, 501 West Ocean Blvd., Suite 4200, Long Beach, CA 90802-4213; phone (562) 980-4001; fax (562) 980... behavior and habitat use of the Weddell seal in the Ross Sea. The applicant is requesting authorization to...

Biotechnological studies in the Far-Eastern Region of Russia.

Science.gov (United States)

Stonik, Valentin A; Mikhailov, Valery V; Bulgakov, Victor P; Zhuravlev, Yuri N

2007-07-01

Achievements and problems in both the studies on natural bioactive compounds from the Far-Eastern higher plants and marine invertebrates and development of the corresponding biotechnologies concerning new drugs and food supplements, as well as pharmaceutical leads are discussed. Special emphasis is made on recent results from the Far-eastern Institutions belonging to the Russian Academy of Sciences, and their application in both medicine and the food industry, as well as on peculiarities of biological and chemical diversity in the North-Western part of Asia and adjoining seas.

Palaeoenvironmental changes across the Danian–Selandian boundary in the North Sea Basin

DEFF Research Database (Denmark)

Clemmensen, Anne; Thomsen, Erik

2005-01-01

cores from Storebælt in the eastern part of the North Sea Basin, we have reconstructed the palaeoenvironmental changes across the boundary. The benthic foraminiferal faunas belong to the “Midway-type fauna”. They are extremely rich and more than 260 taxa have been recognized. Q-mode cluster analysis......, the sea bottom conditions became colder and more acidic. This resulted in partial dissolution of the carbonates and the deposition shifted from marl to clay. Comparison with records from the Western Pyrenees, the Nile Basin and the eastern North America suggests that sea-level changes across the Danian......The Danian–Selandian boundary (not, vert, similar60 Ma) marks the cessation of 40 million years of carbonate deposition in the North Sea Basin and a shift to siliciclastic deposition. On the basis of variations in lithology, benthic and planktonic foraminifera and calcareous nannofossils in three...

Modelling the Seasonal Overturning Circulation in the Red Sea

KAUST Repository

Yao, Fengchao

2015-04-01

The overturning circulation in the Red Sea exhibits a distinct seasonally reversing pattern and is studied using 50-year, high-resolution MIT general circulation model simulations. The seasonal water exchange in the Strait of Bab el Mandeb is successfully simulated, and the structures of the intruding subsurface Gulf of Aden intermediate water are in good agreement with summer observations in 2011. The model results suggest that the summer overturning circulation is driven by the combined effect of the shoaling of the thermocline in the Gulf of Aden resulting from remote winds in the Arabian Sea and an upward surface slope from the Red Sea to the Gulf of Aden set up by local surface winds in the Red Sea. For the winter overturning circulation, the climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24°N. The overturning is accomplished through a cyclonic recirculation and a cross-basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model\\'s winter overturning circulation.

Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from METEOR in the Aegean Sea, Mediterranean Sea and others from 2001-10-18 to 2001-11-11 (NODC Accession 0084620)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0084620 includes discrete sample and profile data collected from METEOR in the Aegean Sea, Mediterranean Sea, Mediterranean Sea - Eastern Basin,...

Trace elements in loggerhead turtles (Caretta caretta) from the eastern Mediterranean Sea: overview and evaluation

International Nuclear Information System (INIS)

Storelli, M.M.; Storelli, A.; D'Addabbo, R.; Marano, C.; Bruno, R.; Marcotrigiano, G.O.

2005-01-01

Concentrations of trace elements (Hg, Cd, Pb, Zn, Cu, Fe, and Se) in different organs and tissues (liver, kidney, muscle tissue, spleen, heart, lung, and fat tissue) of loggerhead turtles Caretta caretta from eastern Mediterranean Sea were determined. The highest levels of mercury and cadmium were found in liver (Hg: 0.43 μg g -1 wet weight; Cd: 3.36 μg g -1 wet weight) and kidney (Hg: 0.16 μg g -1 wet weight; Cd: 8.35 μg g -1 wet weight). For lead the overall concentrations were low and often below the limit of detection. Copper and selenium tended to be higher in liver than in other tissues and organs, while for zinc the concentrations were quite homogenous in the different organs and tissues, except fat tissue (64.7 μg g -1 wet weight) which showed a higher accumulation of this element. For iron the greatest concentrations were observed in liver (409 μg g -1 wet weight) and spleen (221 μg g -1 wet weight). - Cadmium concentrations in samples from turtles may be high enough to affect their health

Age and sex composition of seals killed by polar bears in the eastern Beaufort Sea.

Science.gov (United States)

Pilfold, Nicholas W; Derocher, Andrew E; Stirling, Ian; Richardson, Evan; Andriashek, Dennis

2012-01-01

Polar bears (Ursus maritimus) of the Beaufort Sea enter hyperphagia in spring and gain fat reserves to survive periods of low prey availability. We collected information on seals killed by polar bears (n=650) and hunting attempts on ringed seal (Pusa hispida) lairs (n=1396) observed from a helicopter during polar bear mark-recapture studies in the eastern Beaufort Sea in spring in 1985-2011. We investigated how temporal shifts in ringed seal reproduction affect kill composition and the intraspecific vulnerabilities of ringed seals to polar bear predation. Polar bears primarily preyed on ringed seals (90.2%) while bearded seals (Erignathus barbatus) only comprised 9.8% of the kills, but 33% of the biomass. Adults comprised 43.6% (150/344) of the ringed seals killed, while their pups comprised 38.4% (132/344). Juvenile ringed seals were killed at the lowest proportion, comprising 18.0% (62/344) of the ringed seal kills. The proportion of ringed seal pups was highest between 2007-2011, in association with high ringed seal productivity. Half of the adult ringed seal kills were ≥ 21 years (60/121), and kill rates of adults increased following the peak of parturition. Determination of sex from DNA revealed that polar bears killed adult male and adult female ringed seals equally (0.50, n=78). The number of hunting attempts at ringed seal subnivean lair sites was positively correlated with the number of pup kills (r(2) =0.30, P=0.04), but was not correlated with the number of adult kills (P=0.37). Results are consistent with decadal trends in ringed seal productivity, with low numbers of pups killed by polar bears in spring in years of low pup productivity, and conversely when pup productivity was high. Vulnerability of adult ringed seals to predation increased in relation to reproductive activities and age, but not gender.

Dust-wind interactions can intensify aerosol pollution over eastern China.

Science.gov (United States)

Yang, Yang; Russell, Lynn M; Lou, Sijia; Liao, Hong; Guo, Jianping; Liu, Ying; Singh, Balwinder; Ghan, Steven J

2017-05-11

Eastern China has experienced severe and persistent winter haze episodes in recent years due to intensification of aerosol pollution. In addition to anthropogenic emissions, the winter aerosol pollution over eastern China is associated with unusual meteorological conditions, including weaker wind speeds. Here we show, based on model simulations, that during years with decreased wind speed, large decreases in dust emissions (29%) moderate the wintertime land-sea surface air temperature difference and further decrease winds by -0.06 (±0.05) m s -1 averaged over eastern China. The dust-induced lower winds enhance stagnation of air and account for about 13% of increasing aerosol concentrations over eastern China. Although recent increases in anthropogenic emissions are the main factor causing haze over eastern China, we conclude that natural emissions also exert a significant influence on the increases in wintertime aerosol concentrations, with important implications that need to be taken into account by air quality studies.

Metabolite Profiling of Triterpene Glycosides of the Far Eastern Sea Cucumber Eupentacta fraudatrix and Their Distribution in Various Body Components Using LC-ESI QTOF-MS.

Science.gov (United States)

Popov, Roman S; Ivanchina, Natalia V; Silchenko, Alexandra S; Avilov, Sergey A; Kalinin, Vladimir I; Dolmatov, Igor Yu; Stonik, Valentin A; Dmitrenok, Pavel S

2017-10-02

The Far Eastern sea cucumber Eupentacta fraudatrix is an inhabitant of shallow waters of the south part of the Sea of Japan. This animal is an interesting and rich source of triterpene glycosides with unique chemical structures and various biological activities. The objective of this study was to investigate composition and distribution in various body components of triterpene glycosides of the sea cucumber E. fraudatrix . We applied LC-ESI MS (liquid chromatography-electrospray mass spectrometry) of whole body extract and extracts of various body components for metabolic profiling and structure elucidation of triterpene glycosides from the E. fraudatrix . Totally, 54 compounds, including 26 sulfated, 18 non-sulfated and 10 disulfated glycosides were detected and described. Triterpene glycosides from the body walls, gonads, aquapharyngeal bulbs, guts and respiratory trees were extracted separately and the distributions of the detected compounds in various body components were analyzed. Series of new glycosides with unusual structural features were described in E. fraudatrix , which allow clarifying the biosynthesis of these compounds. Comparison of the triterpene glycosides contents from the five different body components revealed that the profiles of triterpene glycosides were qualitatively similar, and only some quantitative variabilities for minor compounds were observed.

The Tectonic Boundary Between Eastern Subbaisin and South-West Subbasin of the South China Sea Revealed from the Normalized Magnetic Source Strength

Science.gov (United States)

Guo, L.; Meng, X.

2014-12-01

The South China Sea (SCS), surrounded by the Eurasia, Pacific and India-Australia plates, is one of the largest marginal seas in the Western Pacific. It was formed by the interaction of the three plates and the seafloor spreading during Late Oligocene time to Early Miocene time. The boundary between Eastern Subbaisin and South-west Subbasin of the SCS has long been debated in the literature. Refining the boundary is one of the crucial tasks for correctly understanding the seafloor spreading model of the SCS. Due to few drills on the deep ocean basin of the SCS, magnetic data become important information for refining the boundary. However, the interpretation of magnetic data in the SCS suffers from the remanent magnetization of ocean crust as well as igneous rock and seamounts. The conventional reduction-to-pole anomalies at low latitudes usually neglect the remanent magnetization, making the interpretation incorrect. Here, we assembled high-resolution total magnetic intensity (TMI) data around the ocean basin of the SCS, and then did a special transformation of the TMI anomalies with a varying magnetic inclinations algorithm to obtain the normalized source strength (NSS). The NSS has advantage of insensitivity to remanent magnetization, benefitting correct interpretation. The NSS presents discriminative features from east to west in the ocean basin. The boundary of the discriminative features is clear and just ranges from the northeastern edge of the Zhongsha Islands running in the southeast direction to the northeastern edge of the Reed Bank. These imply that magnetic structure and tectonic features in the crust are discriminative between both sides of this boundary. It can be deduced that this boundary is the tectonic boundary between Eastern Subbaisin and South-west Subbasin. We acknowledge the financial support of the National Natural Science Foundation of China (41374093) and the SinoProbe-01-05 project.

Long-Term Trends, Variability and Extremes of In Situ Sea Surface Temperature Measured Along the Eastern Adriatic Coast and its Relationship to Hemispheric Processes

Science.gov (United States)

Grbec, Branka; Matić, Frano; Beg Paklar, Gordana; Morović, Mira; Popović, Ružica; Vilibić, Ivica

2018-02-01

This paper examines long-term series of in situ sea surface temperature (SST) data measured at nine coastal and one open sea stations along the eastern Adriatic Sea for the period 1959-2015. Monthly and yearly averages were used to document SST trends and variability, while clustering and connections to hemispheric indices were achieved by applying the Principal Component Analysis (PCA) and Self-Organizing Maps (SOM) method. Both PCA and SOM revealed the dominance of temporal changes with respect to the effects of spatial differences in SST anomalies, indicating the prevalence of hemispheric processes over local dynamics, such as bora wind spatial inhomogeneity. SST extremes were connected with blocking atmospheric patterns. A substantial warming between 1979 and 2015, in total exceeding 1 °C, was preceded by a period with a negative SST trend, implying strong multidecadal variability in the Adriatic. The strongest connection was found between yearly SST and the East Atlantic (EA) pattern, while North Atlantic Oscillation (NAO) and East Atlantic/West Russia (EAWR) patterns were found to also affect February SST values. Quantification of the Adriatic SST and their connection to hemispheric indices allow for more precise projections of future SST, considered to be rather important for Adriatic thermohaline circulation, biogeochemistry and fisheries, and sensitive to ongoing climate change.

Temperature profiles from mechanical bathythermograph (MBT) casts from the USS WARBLER in the Eastern China Sea and other locations in support of the Fleet Observations of Oceanographic Data (FLOOD) project from 1966-09-19 to 1966-09-27 (NODC Accession 6600396)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — MBT data were collected from the USS WARBLER in support of the Fleet Observations of Oceanographic Data (FLOOD) project. Data were collected in the Eastern China Sea...

Distribution of artificial radionuclides in deep sediments of the Mediterranean Sea

International Nuclear Information System (INIS)

Garcia-Orellana, J.; Pates, J.M.; Masque, P.; Bruach, J.M.; Sanchez-Cabeza, J.A.

2009-01-01

Artificial radionuclides enter the Mediterranean Sea mainly through atmospheric deposition following nuclear weapons tests and the Chernobyl accident, but also through the river discharge of nuclear facility effluents. Previous studies of artificial radionuclides impact of the Mediterranean Sea have focussed on shallow, coastal sediments. However, deep sea sediments have the potential to store and accumulate pollutants, including artificial radionuclides. Deep sea marine sediment cores were collected from Mediterranean Sea abyssal plains (depth > 2000 m) and analysed for 239,240 Pu and 137 Cs to elucidate the concentrations, inventories and sources of these radionuclides in the deepest areas of the Mediterranean. The activity - depth profiles of 210 Pb, together with 14 C dating, indicate that sediment mixing redistributes the artificial radionuclides within the first 2.5 cm of the sedimentary column. The excess 210 Pb inventory was used to normalize 239,240 Pu and 137 Cs inventories for variable sediment fluxes. The 239,240 Pu/ 210 Pb xs ratio was uniform across the entire sea, with a mean value of 1.24 x 10 -3 , indicating homogeneous fallout of 239,240 Pu. The 137 Cs/ 210 Pb xs ratio showed differences between the eastern (0.049) and western basins (0.030), clearly significant impact of deep sea sediments from the Chernobyl accident. The inventory ratios of 239,240 Pu/ 137 Cs were 0.041 and 0.025 in the western and eastern basins respectively, greater than the fallout ratio, 0.021, showing more efficient scavenging of 239,240 Pu in the water column and major sedimentation of 137 Cs in the eastern basin. Although areas with water depths of > 2000 m constitute around 40% of the entire Mediterranean basin, the sediments in these regions only contained 2.7% of the 239,240 Pu and 0.95% of the 137 Cs deposited across the Sea in 2000. These data show that the accumulation of artificial radionuclides in deep Mediterranean environments is much lower than predicted by

Eddy-induced Sea Surface Salinity changes in the tropical Pacific

Science.gov (United States)

Delcroix, T. C.; Chaigneau, A.; Soviadan, D.; Boutin, J.

2017-12-01

We analyse the Sea Surface Salinity (SSS) signature of westward propagating mesoscale eddies in the tropical Pacific by collocating 5 years (2010-2015) of SMOS (Soil Moisture and Ocean Salinity) SSS and altimetry-derived sea level anomalies. The main characteristics of mesoscale eddies are first identified in SLA maps. Composite analyses in the Central and Eastern ITCZ regions then reveal regionally dependent impacts with opposite SSS anomalies for the cyclonic and anticyclonic eddies. In the Central region (where we have the largest meridional SSS gradient), we found dipole-like SSS changes with maximum anomalies on the leading edge of the eddy. In the Eastern region (where we have the largest near-surface vertical salinity gradient) we found monopole-like SSS changes with maximum anomalies in the eddy centre. These dipole/monopole patterns and the rotational sense of eddies suggest the dominant role of horizontal and vertical advection in the Central and Eastern ITCZ regions, respectively.

Geological and geomechanical properties of the carbonate rocks at the eastern Black Sea Region (NE Turkey)

Science.gov (United States)

Ersoy, Hakan; Yalçinalp, Bülent; Arslan, Mehmet; Babacan, Ali Erden; Çetiner, Gözde

2016-11-01

Turkey located in the Alpine-Himalayan Mountain Belt has 35% of the natural stone reserves of the world and has good quality marble, limestone, travertine and onyx reserves especially in the western regions of the country. The eastern Black Sea Region with a 1.4 million meters cubes reserve has a little role on the natural stone production in the country. For this reason, this paper deals with investigation on the potential of carbonate stone in the region and determination of the geological and geo-mechanical properties of these rocks in order to provide economic contribution to the national economy. While the study sites are selected among the all carbonate rock sites, the importance as well as the representative of the sites were carefully considered for the region. After representative samples were analyzed for major oxide and trace element compositions to find out petrochemical variations, the experimental program conducted on rock samples for determination of both physical and strength properties of the carbonate rocks. The results of the tests showed that there are significant variations in the geo-mechanical properties of the studied rock groups. The density values vary from 2.48 to 2.70 gr/cm3, water absorption by weight values range from 0.07 to 1.15% and the apparent porosity of the carbonate rocks are between 0.19 and 3.29%. However, the values of the UCS shows variation from 36 to 80 MPa. Tensile and bending strength values range from 3.2 to 7.5 MPa and 6.0-9.2 MPa respectively. Although the onyx samples have the lowest values of apparent porosity and water absorption by weight, these samples do not have the highest values of UCS values owing to occurrence of the micro-cracks. The UCS values of the rock samples were also found after cycling tests However, the limestone samples have less than 5% deterioration after freezing-thawing and wetting-drying tests, but travertine and onyx samples have more than 15% deterioration. Exception of the apparent

Observed vulnerability of Filchner-Ronne Ice Shelf to wind-driven inflow of warm deep water

Science.gov (United States)

Darelius, E.; Fer, I.; Nicholls, K. W.

2016-01-01

The average rate of melting at the base of the large Filchner-Ronne Ice Shelf in the southern Weddell Sea is currently low, but projected to increase dramatically within the next century. In a model study, melt rates increase as changing ice conditions cause a redirection of a coastal current, bringing warm water of open ocean origin through the Filchner Depression and into the Filchner Ice Shelf cavity. Here we present observations from near Filchner Ice Shelf and from the Filchner Depression, which show that pulses of warm water already arrive as far south as the ice front. This southward heat transport follows the eastern flank of the Filchner Depression and is found to be directly linked to the strength of a wind-driven coastal current. Our observations emphasize the potential sensitivity of Filchner-Ronne Ice Shelf melt rates to changes in wind forcing. PMID:27481659

Simulation of Tsunami Propagation at East Sea along the Korean Peninsula

International Nuclear Information System (INIS)

Kang, Keum Seok; Choi, Weon Hak; Kim, Chong Hak; Jin, So Beom

2005-01-01

The East Sea is one of the most vulnerable regions to unexpected Tsunami attacks in the world. Many catastrophic tsunamis have been occurred in this region. Among them, the Central East Sea tsunami occurred in 1983 has been recorded as the most devastating tsunami in modern Korean history. By employing a combined numerical model, the run-up heights of the tsunami are estimated along the Eastern coastline of the Korean Peninsula. The computed results are compared with available field measurements. A very reasonable agreement is observed. Several nuclear power plants are located along the Eastern coastline of the Korean Peninsula to get enough amount of cooling water. Furthermore, several more plants are now under construction. Generally, for the safe operation of nuclear power plants, a sea level drop may be more serious than a sea level rise. Once the water intake facilities, especially the bell mouth of a pump, are exposed above a sea water level, it will lead to the shutdown of a nuclear power plant. Sometimes the inhaled air can result in abrupt pressure surging within a mechanical cooling water system. Moreover, the ESWP (Essential Service Water Pump) is related to the safety of reactor. Thus, variation of sea level caused by tsunamis should be conservatively and accurately estimated

Development of ice floe tracker algorithm to measure Lagrangian statistics in the eastern Greenland coast

Science.gov (United States)

Lopez, Rosalinda; Wilhelmus, Monica M.; Schodlok, Michael; Klein, Patrice

2017-11-01

Sea ice export through Fram Strait is a key component of the Arctic climate system. The East Greenland Current (EGC) carries most of the sea ice southwards until it melts. Lagrangian methods using sea ice buoys have been used to map ice features in polar regions. However, their spatial and temporal coverage is limited. Satellite data can provide a better tool to map sea ice flow and its variability. Here, an automated sea ice floe detection algorithm uses ice floes as tracers for surface ocean currents. We process Moderate Resolution Imaging Spectroradiometer satellite images to track ice floes (length scale 5-10 km) in the north-eastern Greenland Sea region. Our matlab-based routines effectively filter out clouds and adaptively modify the images to segment and identify ice floes. Ice floes were tracked based on persistent surface features common in successive images throughout 2016. Their daily centroid locations were extracted and its resulting trajectories are used to describe surface circulation and its variability using differential kinematic parameters. We will discuss the application of this method to a longer time series and larger spatial coverage. This enables us to derive the inter-annual variability of mesoscale features along the eastern coast of Greenland. Supported by UCR Mechanical Engineering Departmental Fellowship.

Sea-level trend in the South China Sea observed from 20 years of along-track satellite altimetric data

DEFF Research Database (Denmark)

Cheng, Yongcun; Xu, Qing; Andersen, Ole Baltazar

2014-01-01

The sea-level trend in the South China Sea (SCS) is investigated based on 20 years of along-track data from TOPEX and Jason-1/2 satellite altimetry. The average sea-level rise over all the regions in the study area is observed to have a rate of 5.1 ± 0.8 mm year-1 for the period from 1993 to 2012....... The steric sea level contributes 45% to the observed sea-level trend. These results are consistent with previous studies. In addition, the results demonstrate that the maximum sea-level rise rate of 8.4 mm year-1 is occurring off the east coast of Vietnam and eastern part of SCS. During 2010-2011, the La...... Niña event was highly correlated with the dramatic sea-level rise in the SCS; La Niña events were also associated with the maximum rate of sea rise off the east coast of Vietnam, which occurred during 1993 and 2012. We also evaluated the trends in the geophysical (e.g. dynamical atmospheric correction...

New Fisheries-related data from the Mediterranean Sea (November, 2016

Directory of Open Access Journals (Sweden)

A. ANASTASOPOULOU

2016-11-01

Full Text Available In this fourth Collective Article, with fisheries-related data from the Mediterranean, we present weight-length relationships for eight deep-sea fish species (Brama brama, Conger conger, Etmopterus spinax, Molva macrophthalma, Mora moro, Pagellus bogaraveo, Phycis blennoides from the Eastern Ionian Sea; Scyliorhinus canicula from various locations in the Mediterranean Sea and weight-length relationships and condition factor of five Mugilidae species (Liza aurata, Liza saliens, Liza ramada, Mugil cephalus, Chelon labrosus from a Mediterranean lagoon in the Ionian Sea. Moreover, we present otolith weight, fish length and otolith length relationships of the red mullet (Mullus barbatus in the Aegean and Ionian Sea and otolith weight relationships in European hake (Merluccius merluccius from the Greek Seas.

Halocline water formation in the Barents Sea

Science.gov (United States)

Steele, Michael; Morison, James H.; Curtin, Thomas B.

1995-01-01

Hydrographic data from the first phase of the Coordinated Eastern Arctic Experiment (CEAREX) are analyzed. The data consist of temperature and salinity measurements made by a ship-based conductivity-temperature-depth (CTD) instrument and by a drifting SALARGOS buoy. These data were collected in the autumn and early winter of 1988-1989 in the northern Barents Sea, mostly in ice-covered conditions and then across the marginal ice zone (MIZ). The data show that relatively warm, salty water of Atlantic origin is modified by air cooling and ice melting to produce lighter water that has properties identical to (lower) halocline water found in the Arctic Ocean. This occurs mostly at the MIZ and to a lesser degree within the ice pack itself. At the MIZ the halocline water subjects underneath the lighter meltwater that resides directly under the ice pack; geostrophic velocity calculations indicate that it then turns eastward and flows toward the Kara Sea, in keeping with previous chemical tracer analyses. A rough calculation reveals that the amount of halocline water formed in this way in the Barents Sea and Fram Strait is 30-50% of that formed by ice growth in eastern Arctic polynyas.

XXI century projections of wind-wave conditions and sea-level rise in the Black sea

Science.gov (United States)

Polonsky, A.; Garmashov, A.; Fomin, V.; Valchev, N.; Trifonova, E.

2012-04-01

Projection of regional climate changes for XXI century is one of the priorities of EC environmental programme. Potential worsening of the waves' statistics, sea level rise and extreme surges are the principal negative consequences of the climate change for marine environment. That is why the main purpose of this presentation is to discuss the above issue for the Black sea region (with a strong focus to the south-west subregion because the maximum heights of waves exceeding 10 m occur just here) using output of several global coupled models (GCM) for XXI century, wave simulation, long-term observations of sea level and statistical techniques. First of all we tried to choose the best coupled model (s) simulated the Black sea climate change and variability using the control experiments for 20 century (203). The principal result is as follows. There is not one model which is simulating adequately even one atmospheric parameter for all seasons. Therefore we considered (for the climate projection) different outputs form various models. When it was possible we calculated also the ensemble mean projection for the selected model (s) and emission scenarios. To calculate the wave projection we used the output of SWAN model forced by the GCM wind projection for 2010 to 2100. To estimate the sea level rise in XXI century and future surges statistics we extrapolate the observed sea level rise tendencies, statistical relation between wave heights and sea level and wave scenarios. Results show that in general, the climate change in XXI century doesn't lead to the catastrophic change of the Black sea wind-wave statistics including the extreme waves in the S-W Black sea. The typical atmospheric pattern leading to the intense storm in the S-W Black sea is characterized by the persistent anticyclonic area to the North of the Black sea and cyclonic conditions in the Southern Black sea region. Such pressure pattern causes persistent and strong eastern or north-eastern wind which

Vertical nutrient fluxes, turbulence and the distribution of chlorophyll a in the north-eastern North Sea

Science.gov (United States)

Bendtsen, Jørgen; Richardson, Katherine

2017-04-01

During summer the northern North Sea is characterized by nutrient rich bottom water masses and nutrient poor surface layers. This explains the distribution of chlorophyll a in the water column where a subsurface maximum, referred to as the deep chlorophyll maximum (DCM), often is present during the growth season. Vertical transport of nutrients between bottom water masses and the well lit surface layer stimulates phytoplankton growth and this generally explains the location of the DCM. However, a more specific understanding of the interplay between vertical transports, nutrient fluxes and phytoplankton abundance is required for identifying the nature of the vertical transport processes, e.g the role of advection versus vertical turbulent diffusion or the role of localized mixing associated with mesoscale eddies. We present results from the VERMIX study in the north-eastern North Sea where nutrients, chlorophyll a and turbulence profiles were measured along five north-south directed transects in July 2016. A high-resolution sampling program, with horizontal distances of 1-10 km between CTD-stations, resolved the horizontal gradients of chlorophyll a across the steep bottom slope from the relatively shallow central North Sea ( 50-80 m) towards the deep Norwegian Trench (>700 m). Low oxygen concentrations in the bottom water masses above the slope indicated enhanced biological production where vertical mixing would stimulate phytoplankton growth around the DCM. Measurements of variable fluorescence (Fv/Fm) showed elevated values in the DCM which demonstrates a higher potential for electron transport in the Photosystem II in the phytoplankton cells, i.e. an indication of nutrient-rich conditions favorable for phytoplankton production. Profiles of the vertical shear and microstructure of temperature and salinity were measured by a VMP-250 turbulence profiler and the vertical diffusion of nutrients was calculated from the estimated vertical turbulent diffusivity and the

Building Coastal Resilience to sea-level rise and storm hazards: supporting decisions in the NE USA, Gulf of Mexico, and eastern Caribbean

Science.gov (United States)

Shepard, C.; Beck, M. W.; Gilmer, B.; Ferdana, Z.; Raber, G.; Agostini, V.; Whelchel, A.; Stone, J.

2012-12-01

Coastal communities are increasingly vulnerable to coastal hazards including storm surge and sea level rise. We describe the use of Coastal Resilience, an approach to help support decisions to reduce socio-economic and ecological vulnerability to coastal hazards. We provide examples of this work from towns and cities around Long Island Sound (NY, CT) and the Gulf of Mexico (FL, AL, MS, LA, TX) in the USA and from the Eastern Caribbean (Grenada, St. Vincent and the Grenadines). All of these shores are densely populated and have significant coastal development only centimetres above the sea. This makes people and property very vulnerable and threatens coastal wetlands (marsh, mangrove) and reefs (oyster, coral) that provide habitat and natural buffers to storms while providing other ecosystem services. We describe this work specifically and then offer broader perspectives and recommendations for using ecological habitats to reduce vulnerability to coastal hazards. The Nature Conservancy's Coastal Resilience approach is driven by extensive community engagement and uses spatial information on storm surge, sea level rise, ecological and socio-economic variables to identify options for reducing the vulnerability of human and natural communities to coastal hazards (http://www.coastalresilience.org). We have worked with local communities to map current and future coastal hazards and to identify the vulnerable natural resources and human communities. Communities are able to visualize potential hazard impacts and identify options to reduce them within their existing planning and regulatory frameworks.

Evolutionary melting pots: a biodiversity hotspot shaped by ring diversifications around the Black Sea in the Eastern tree frog (Hyla orientalis).

Science.gov (United States)

Dufresnes, Christophe; Litvinchuk, Spartak N; Leuenberger, Julien; Ghali, Karim; Zinenko, Oleksandr; Stöck, Matthias; Perrin, Nicolas

2016-09-01

Hotspots of intraspecific genetic diversity, which are of primary importance for the conservation of species, have been associated with glacial refugia, that is areas where species survived the Quaternary climatic oscillations. However, the proximate mechanisms generating these hotspots remain an open issue. Hotspots may reflect the long-term persistence of large refugial populations; alternatively, they may result from allopatric differentiation between small and isolated populations, that later admixed. Here, we test these two scenarios in a widely distributed species of tree frog, Hyla orientalis, which inhabits Asia Minor and southeastern Europe. We apply a fine-scale phylogeographic survey, combining fast-evolving mitochondrial and nuclear markers, with a dense sampling throughout the range, as well as ecological niche modelling, to understand what shaped the genetic variation of this species. We documented an important diversity centre around the Black Sea, composed of multiple allopatric and/or parapatric diversifications, likely driven by a combination of Pleistocene climatic fluctuations and complex regional topography. Remarkably, this diversification forms a ring around the Black Sea, from the Caucasus through Anatolia and eastern Europe, with terminal forms coming into contact and partially admixing in Crimea. Our results support the view that glacial refugia generate rather than host genetic diversity and can also function as evolutionary melting pots of biodiversity. Moreover, we report a new case of ring diversification, triggered by a large, yet cohesive dispersal barrier, a very rare situation in nature. Finally, we emphasize the Black Sea region as an important centre of intraspecific diversity in the Palearctic with implications for conservation. © 2016 John Wiley & Sons Ltd.

The EU’s Black Sea Policies: Any Hopes for Success?

Directory of Open Access Journals (Sweden)

Sinem Akgül Açıkmeşe

2012-01-01

Full Text Available he 2004-2007 enlargements brought the EU onto the shores of the Black Sea region which is encircled with complex insecurities. Since then, the EU has been actively engaged in developing a vision for this problematic region through the various instruments of enlargement, CFSP/CSDP, European Neighborhood Policy, Black Sea Synergy as well as the Eastern Partnership. This paper aims at analysing the efficacy of EU’s Black Sea policies in providing regional security, with a particular and a comparative focus on the impact of the Synergy as the only genuine regional Black Sea strategy.

The radioactivity of the sea

International Nuclear Information System (INIS)

Walker, M.I.; Rose, K.S.B.

1990-01-01

The radioactivity in the world's surface sea water averages 13.6 Bq/kg of water. Over 88% of this activity arises from a single natural radionuclide, 40 K, and 7% of the remainder results from nuclear weapon test fallout. Variations in the radioactivity occur due to changes in salinity, weapon test fallout and discharges of artificial radionuclides, and are examined here on the basis of published measurements. The most radioactive sea identified by these measurements is the Dead Sea, which averages 178 Bq/kg due to its high salinity. Other enclosed, highly saline waters can be expected to have similar levels. The radioactivity in open seas varies within a much narrower range, generally within 20% of the world average. The highest averages are found in the Persian Gulf (22 Bq/kg), the Red Sea (15 Bq/kg) and the Eastern Mediterranean (14.6 Bq/kg). The Irish Sea averaged 13.7 Bq/kg in 1987, with the effect of the Sellafield discharges being partly offset by lower than average salinity. Although higher levels occurred in the Irish Sea during the 1970s when the Sellafield discharges were higher, the average level has always been much less than that in the Dead Sea, so that the Irish Sea has never been the most radioactive sea in the world. Exceptionally low levels of radioactivity (4 Bq/kg) occur in the Baltic Sea due to dilution by fresh water. (author)

Sea level anomaly in the North Atlantic and seas around Europe: Long-term variability and response to North Atlantic teleconnection patterns.

Science.gov (United States)

Iglesias, Isabel; Lorenzo, M Nieves; Lázaro, Clara; Fernandes, M Joana; Bastos, Luísa

2017-12-31

Sea level anomaly (SLA), provided globally by satellite altimetry, is considered a valuable proxy for detecting long-term changes of the global ocean, as well as short-term and annual variations. In this manuscript, monthly sea level anomaly grids for the period 1993-2013 are used to characterise the North Atlantic Ocean variability at inter-annual timescales and its response to the North Atlantic main patterns of atmospheric circulation variability (North Atlantic Oscillation, Eastern Atlantic, Eastern Atlantic/Western Russia, Scandinavian and Polar/Eurasia) and main driven factors as sea level pressure, sea surface temperature and wind fields. SLA variability and long-term trends are analysed for the North Atlantic Ocean and several sub-regions (North, Baltic and Mediterranean and Black seas, Bay of Biscay extended to the west coast of the Iberian Peninsula, and the northern North Atlantic Ocean), depicting the SLA fluctuations at basin and sub-basin scales, aiming at representing the regions of maximum sea level variability. A significant correlation between SLA and the different phases of the teleconnection patterns due to the generated winds, sea level pressure and sea surface temperature anomalies, with a strong variability on temporal and spatial scales, has been identified. Long-term analysis reveals the existence of non-stationary inter-annual SLA fluctuations in terms of the temporal scale. Spectral density analysis has shown the existence of long-period signals in the SLA inter-annual component, with periods of ~10, 5, 4 and 2years, depending on the analysed sub-region. Also, a non-uniform increase in sea level since 1993 is identified for all sub-regions, with trend values between 2.05mm/year, for the Bay of Biscay region, and 3.98mm/year for the Baltic Sea (no GIA correction considered). The obtained results demonstrated a strong link between the atmospheric patterns and SLA, as well as strong long-period fluctuations of this variable in spatial and

Body Size Regression Formulae, Proximate Composition and Energy Density of Eastern Bering Sea Mesopelagic Fish and Squid.

Science.gov (United States)

Sinclair, Elizabeth H; Walker, William A; Thomason, James R

2015-01-01

The ecological significance of fish and squid of the mesopelagic zone (200 m-1000 m) is evident by their pervasiveness in the diets of a broad spectrum of upper pelagic predators including other fishes and squids, seabirds and marine mammals. As diel vertical migrators, mesopelagic micronekton are recognized as an important trophic link between the deep scattering layer and upper surface waters, yet fundamental aspects of the life history and energetic contribution to the food web for most are undescribed. Here, we present newly derived regression equations for 32 species of mesopelagic fish and squid based on the relationship between body size and the size of hard parts typically used to identify prey species in predator diet studies. We describe the proximate composition and energy density of 31 species collected in the eastern Bering Sea during May 1999 and 2000. Energy values are categorized by body size as a proxy for relative age and can be cross-referenced with the derived regression equations. Data are tabularized to facilitate direct application to predator diet studies and food web models.

Boron/calcium ratios in Globigerinoides ruber from the Arabian Sea: Implications for controls on boron incorporation

Digital Repository Service at National Institute of Oceanography (India)

Naik, S.S.; Naidu, P.D.

of Globigerinoides ruber from the Ocean Drilling Program (ODP) Site 723A (western Arabian Sea) and Core AAS9/21 (eastern Arabian Sea) from the last 22 kyr were analysed for B/Ca, delta¹⁸O and Mg/Ca. B/Ca was compared to reconstructed salinity and sea...

Climate change facilitated range expansion of the non-native angular crab Goneplax rhomboides into the North Sea

NARCIS (Netherlands)

Neumann, H.; Boois, de I.J.; Kroncke, I.; Reiss, H.

2013-01-01

The angular crab Goneplax rhomboides is native to the north-eastern Atlantic and Mediterranean Sea. It has rarely been reported from the North Sea, with no evidence of sustainable populations. Compiled survey data, however, revealed an increasing abundance of this species in the North Sea since

Genetic architecture of the marbled goby Pomatoschistus marmoratus (Perciformes, Gobiidae) in the Mediterranean Sea.

Science.gov (United States)

Mejri, Randa; Arculeo, Marco; Hassine, Oum Kalthoum Ben; Brutto, Sabrina Lo

2011-02-01

The marbled goby Pomatoschistus marmoratus, a species inhabiting coastal Mediterranean lagoons, has been studied by measuring its mitochondrial DNA variation. This analysis revealed a Mediterranean west vs east split and, subsequently, an eastern differentiation among the Libyan-Tunisian Gulf, the Adriatic Sea and the Aegean Sea. The high cohesion between the samples collected in the vast area of western Mediterranean contrasts with the genetic mosaic of the more sub-structured eastern Mediterranean. This western homogeneity can not yet be fully explained even if a human-mediated migratory flow, due to a maritime traffic, has been posited. The pattern in the eastern basin revealed a genetic architecture possibly due to the non-migratory habit of the gobid. Within this perspective, the role of the Mediterranean lagoon habitat should be related to how much it amplifies the effects of historical (e.g. past sea-level changes) and environmental (e.g. present-day hydrographic regime) processes as regards the genetic structure of the inhabiting species. Copyright © 2010 Elsevier Inc. All rights reserved.

Eastward shift and maintenance of Arabian Sea oxygen minimum zone: Understanding the paradox

Science.gov (United States)

Acharya, Shiba Shankar; Panigrahi, Mruganka K.

2016-09-01

The dominance of Oxygen Minimum Zone in the eastern part of the Arabian Sea (ASOMZ) instead of the more bio-productive and likely more oxygen consuming western part is the first part of the paradox. The sources of oxygen to the ASOMZ were evaluated through the distributions of different water masses using the extended optimum multiparameter (eOMP) analysis, whereas the sinks of oxygen were evaluated through the organic matter remineralization, using the apparent oxygen utilization (AOU). The contributions of major source waters to the Arabian Sea viz. Indian Deep water (dIDW), Indian Central water (ICW), Persian Gulf Water (PGW) and Red Sea Water (RSW) have been quantified through the eOMP analysis which shows that the PGW and RSW are significant for the eastward shift of ASOMZ instead of voluminous ICW and dIDW. The distribution of Net Primary Production (NPP) and AOU clearly suggest the transport of organic detritus from the highly productive western Arabian Sea to its eastern counterpart which adds to the eastward shifting of ASOMZ. A revised estimate of the seasonal variation of areal extent and volume occupied by ASOMZ through analysis of latest available data reveals a distinct intensification of ASOMZ by 30% and increase in its volume by 5% during the spring-summer transition. However, during this seasonal transition the productivity in the Arabian Sea shows 100% increase in mean NPP. This disparity between ASOMZ and monsoonal variation of productivity is the other part of the paradox, which has been constrained through apparent oxygen utilization, Net Primary Production along with a variation of core depths of source waters. This study reveals a subtle balance between the circulation of marginal oxygen-rich water masses from the western Arabian Sea and organic matter remineralization in the eastern Arabian Sea in different seasons that explains the maintenance of ASOMZ throughout the year.

Study on tsunami due to offshore earthquakes for Korea coast. Literature survey and numerical simulation on earthquake and tsunami in the Japan Sea and the East China Sea

International Nuclear Information System (INIS)

Matsuyama, Masafumi; Aoyagi, Yasuhira; Inoue, Daiei; Choi, Weon-Hack; Kang, Keum-Seok

2008-01-01

In Korea, there has been a concern on tsumami risks for the Nuclear Power Plants since the 1983 Nihonkai-Chubu earthquake tsunami. The maximum run-up height reached 4 m to north of the Ulchin nuclear power plant site. The east coast of Korea was also attacked by a few meters high tsunami generated by the 1993 Hokkaido Nansei-Oki earthquake. Both source areas of them were in the areas western off Hokkaido to the eastern margin of the Japan Sea, which remains another tsunami potential. Therefore it is necessary to study tsunami risks for coast of Korea by means of geological investigation and numerical simulation. Historical records of earthquake and tsunami in the Japan Sea were re-compiled to evaluate tsunami potential. A database of marine active faults in the Japan Sea was compiled to decide a regional potential of tsunami. Many developed reverse faults are found in the areas western off Hokkaido to the eastern margin of the Japan Sea. The authors have found no historical earthquake in the East China Sea which caused tunami observed at coast of Korea. Therefore five fault models were determined on the basis of the analysis results of historical records and recent research results of fault parameter and tunami. Tsunami heights were estimated by numerical simulation of nonlinear dispersion wave theory. The results of the simulations indicate that the tsunami heights in these cases are less than 0.25 m along the coast of Korea, and the tsunami risk by these assumed faults does not lead to severe impact. It is concluded that tsunami occurred in the areas western off Hokkaido to the eastern margin of the Japan Sea leads the most significant impact to Korea consequently. (author)

Lead in blood and eggs of the sea turtle, Lepidochelys olivacea, from the Eastern Pacific: Concentration, isotopic composition and maternal transfer

International Nuclear Information System (INIS)

Paez-Osuna, F.; Calderon-Campuzano, M.F.; Soto-Jimenez, M.F.; Ruelas-Inzunza, J.R.

2010-01-01

Concentrations of lead were assessed in the sea turtle, Lepidochelys olivacea, from a nesting colony of the Eastern Pacific. Twenty-five female turtles were sampled and a total of 250 eggs were collected during the 'arribada' event of the 2005-2006 season. Considering the nesting season, the maternal transfer of lead (Pb) via egg-laying, in terms of metal burden in whole body, was 0.5%. Pb concentrations (in dry weight) in blood (0.95 ± 0.18 μg g -1 ) and egg samples (yolk, 0.80 ± 0.10 μg g -1 ; albumen, 1.08 ± 0.20 μg g -1 ; eggshell, 1.05 ± 0.20 μg g -1 ) were comparable or even lower than those found in other sea turtles. The isotope ratios ( 206 Pb/ 207 Pb and 206 Pb/ 208 Pb) in blood (1.183 ± 0.0006 and 2.452 ± 0.0006, respectively) were comparable to that of natural Pb-bearing bedrock in Mexico (1.188 ± 0.005 and 2.455 ± 0.008, respectively). According to international norms of Pb, the health of this population and its habitats is acceptable for Pb and corresponds to basic levels of a nearly pristine environment.

Mass-induced sea level variations in the Red Sea from GRACE, steric-corrected altimetry, in situ bottom pressure records, and hydrographic observations

Science.gov (United States)

Feng, W.; Lemoine, J.-M.; Zhong, M.; Hsu, H. T.

2014-08-01

An annual amplitude of ∼18 cm mass-induced sea level variations (SLV) in the Red Sea is detected from the Gravity Recovery and Climate Experiment (GRACE) satellites and steric-corrected altimetry from 2003 to 2011. The annual mass variations in the region dominate the mean SLV, and generally reach maximum in late January/early February. The annual steric component of the mean SLV is relatively small (mass-induced SLV. In situ bottom pressure records at the eastern coast of the Red Sea validate the high mass variability observed by steric-corrected altimetry and GRACE. In addition, the horizontal water mass flux of the Red Sea estimated from GRACE and steric-corrected altimetry is validated by hydrographic observations.

Relations between tectonics and sedimentation along the Eastern Sardinian margin (Western Tyrrhenian Sea) : from rifting to reactivation

Science.gov (United States)

Gaullier, Virginie; Chanier, Frank; Vendeville, Bruno; Lymer, Gaël; Maillard, Agnès; Thinon, Isabelle; Lofi, Johanna; Sage, Françoise; Giresse, Pierre; Bassetti, Maria-Angela

2014-05-01

The offshore-onshore project "METYSS-METYSAR" aims at better understand the Miocene-Pliocene relationships between crustal tectonics, salt tectonics, and sedimentation along the Eastern Sardinian margin, Western Tyrrhenian Sea. In this key-area, the Tyrrhenian back-arc basin underwent recent rifting (9-5 Ma), pro parte coeval with the Messinian Salinity Crisis (MSC, 5.96-5.33 Ma), sea-floor spreading starting during Pliocene times. Thereby, the Tyrrhenian basin and the Eastern Sardinian margin are excellent candidates for studying the mechanisms of extreme lithospheric stretching and thinning, the role of pre-existing structural fabric during and after rifting, and the reactivation of a passive margin and the associated deformation and sedimentation patterns during the MSC. We looked at the respective contributions of crustal and salt tectonics in quantifying vertical and horizontal movements, using especially the seismic markers of the MSC. Overall, we delineate the history of rifting and tectonic reactivation in the area. The distribution maps respectively of the Messinian Erosion Surface and of Messinian units (Upper Unit and Mobile Unit) show that a rifted basin already existed by Messinian time. This reveals a major pre-MSC rifting across the entire domain. Because salt tectonics can create fan-shaped geometries in sediments, syn-rift deposits have to be carefully re-examined in order to decipher the effects of crustal tectonics (rifting) and thin-skinned salt tectonics. Our data surprisingly show that there are no clues for Messinian syn-rift sediments along the East-Sardinia Basin and Cornaglia Terrace, hence no evidence for rifting after Late Tortonian times. Nevertheless, widespread deformation occurred during the Pliocene and can only be attributed to post-rift reactivation. This reactivation is characterized not only by normal faulting but also by contractional structures. Some Pliocene vertical movements caused localized gravity gliding of the mobile

Contemporary Arctic Sea Level

Science.gov (United States)

Cazenave, A. A.

2017-12-01

During recent decades, the Arctic region has warmed at a rate about twice the rest of the globe. Sea ice melting is increasing and the Greenland ice sheet is losing mass at an accelerated rate. Arctic warming, decrease in the sea ice cover and fresh water input to the Arctic ocean may eventually impact the Arctic sea level. In this presentation, we review our current knowledge of contemporary Arctic sea level changes. Until the beginning of the 1990s, Arctic sea level variations were essentially deduced from tide gauges located along the Russian and Norwegian coastlines. Since then, high inclination satellite altimetry missions have allowed measuring sea level over a large portion of the Arctic Ocean (up to 80 degree north). Measuring sea level in the Arctic by satellite altimetry is challenging because the presence of sea ice cover limits the full capacity of this technique. However adapted processing of raw altimetric measurements significantly increases the number of valid data, hence the data coverage, from which regional sea level variations can be extracted. Over the altimetry era, positive trend patterns are observed over the Beaufort Gyre and along the east coast of Greenland, while negative trends are reported along the Siberian shelf. On average over the Arctic region covered by satellite altimetry, the rate of sea level rise since 1992 is slightly less than the global mea sea level rate (of about 3 mm per year). On the other hand, the interannual variability is quite significant. Space gravimetry data from the GRACE mission and ocean reanalyses provide information on the mass and steric contributions to sea level, hence on the sea level budget. Budget studies show that regional sea level trends over the Beaufort Gyre and along the eastern coast of Greenland, are essentially due to salinity changes. However, in terms of regional average, the net steric component contributes little to the observed sea level trend. The sea level budget in the Arctic

Black Sea coastal forecasting system

Directory of Open Access Journals (Sweden)

A. I. Kubryakov

2012-03-01

Full Text Available The Black Sea coastal nowcasting and forecasting system was built within the framework of EU FP6 ECOOP (European COastalshelf sea OPerational observing and forecasting system project for five regions: the south-western basin along the coasts of Bulgaria and Turkey, the north-western shelf along the Romanian and Ukrainian coasts, coastal zone around of the Crimea peninsula, the north-eastern Russian coastal zone and the coastal zone of Georgia. The system operates in the real-time mode during the ECOOP project and afterwards. The forecasts include temperature, salinity and current velocity fields. Ecosystem model operates in the off-line mode near the Crimea coast.

Regional Hydrological Cycle over the Red Sea in ERA-Interim

KAUST Repository

Zolina, Olga; Dufour, Ambroise; Gulev, Sergey K.; Stenchikov, Georgiy L.

2016-01-01

The major sources of atmospheric moisture over the Red Sea are analyzed using ERA-Interim for the 1979-2013 period. The vertical structure of moisture transports across the coastlines has been computed separately for the western and eastern coasts of the Red Sea. The vertical structure of the moisture transport from the Red Sea to the continents is dominated by a breeze-like circulation in the near-surface layer and the Arabian high above 850 hPa. The lower-layer, breeze-like circulation is acting to export the moisture to the northwest of Africa and to the Arabian Peninsula and contributes about 80% of the moisture exports from the Red Sea, dominating over the transport in the upper layer, where the moisture is advected to the Arabian Peninsula in the northern part of the sea and to the African continent in the southern part. Integrated moisture divergence over the Red Sea decreased from the early 1980s to 1997 and then increased until the 2010s. Associated changes in the moisture export were provided primarily by the increasing intensity of the breeze-associated transports. The transports above the boundary layer, while being strong across the western and the eastern coasts, have a smaller effect on the net moisture export. The interannual variability of the moisture export in the near-surface layer was found to be closely correlated with the variability in sea surface temperature, especially in summer. Implications of the observed changes in the moisture advection for the hydrological cycle of the Middle East are discussed.

Regional Hydrological Cycle over the Red Sea in ERA-Interim

KAUST Repository

Zolina, Olga

2016-09-30

The major sources of atmospheric moisture over the Red Sea are analyzed using ERA-Interim for the 1979-2013 period. The vertical structure of moisture transports across the coastlines has been computed separately for the western and eastern coasts of the Red Sea. The vertical structure of the moisture transport from the Red Sea to the continents is dominated by a breeze-like circulation in the near-surface layer and the Arabian high above 850 hPa. The lower-layer, breeze-like circulation is acting to export the moisture to the northwest of Africa and to the Arabian Peninsula and contributes about 80% of the moisture exports from the Red Sea, dominating over the transport in the upper layer, where the moisture is advected to the Arabian Peninsula in the northern part of the sea and to the African continent in the southern part. Integrated moisture divergence over the Red Sea decreased from the early 1980s to 1997 and then increased until the 2010s. Associated changes in the moisture export were provided primarily by the increasing intensity of the breeze-associated transports. The transports above the boundary layer, while being strong across the western and the eastern coasts, have a smaller effect on the net moisture export. The interannual variability of the moisture export in the near-surface layer was found to be closely correlated with the variability in sea surface temperature, especially in summer. Implications of the observed changes in the moisture advection for the hydrological cycle of the Middle East are discussed.

Ichthyofauna of the Eastern Coast Bays of the Novaya Zemlya Archipelago

Science.gov (United States)

Bolshakova, Ya. Yu.; Bolshakov, D. V.

2018-03-01

Based on 2014-2016 studies and published data on the ichthyofauna composition near the eastern coast of Novaya Zemlya, a revised list of fish fauna has been compiled. It includes 30 species from 23 genera and 13 families. The taxonomic diversity of ichthyofauna, its characteristics in respect to geographic range and biotopic groups of fish are considered. In general, ichthyological communities in bays off the eastern coast are similar in the species ratio to the communities in the open Kara Sea, and do not demonstrate any essential features of isolation.

Biodiversity of deep-sea demersal megafauna in western and central Mediterranean basins

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Samuele Tecchio

2011-06-01

Full Text Available Abundance, biomass and diversity patterns of bathyal and abyssal Mediterranean megafauna (fishes and invertebrates were analyzed in the western Balearic Sea, the western Ionian Sea and the eastern Ionian Sea. Sampling was conducted with a Otter-trawl Maireta System (OTMS at depths ranging from 600 to 4000 m. A series of ecological indicators were computed: total abundance and biomass, Margalef species richness, Shannon-Wiener diversity and Pielou’s index of evenness. A multidimensional scaling was applied, indicating that the megafauna communities were grouped by depth, while geographic area had a less defined influence. Margalef richness declined with depth in all three areas, but more steeply in the western Ionian Sea. Pielou’s evenness behaved differently in the three zones, showing a V-shaped curve in the eastern Ionian while showing a decreasing pattern in the other two areas. At lower slope depths, massive presence of the fishes Alepocephalus rostratus in the western basin and Bathypterois mediterraneus in the central basin caused a sharp reduction in evenness.

ORGANOCHLORINE CONTAMINANTS IN SEA TURTLES FROM THE EASTERN PACIFIC

Science.gov (United States)

We measured organochlorine residues in three species of sea turtles from the Baja California peninsula, Mexico. Seventeen of 21 organochlorine pesticides analyzed were detected, with heptachlor epoxide and y-hexachlorocyclohexane the most prevalent in 14 (40%) and 11 (31%) of th...

Application of remotely piloted aircraft systems in observing the atmospheric boundary layer over Antarctic sea ice in winter

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Marius O. Jonassen

2015-10-01

Full Text Available The main aim of this paper is to explore the potential of combining measurements from fixed- and rotary-wing remotely piloted aircraft systems (RPAS to complement data sets from radio soundings as well as ship and sea-ice-based instrumentation for atmospheric boundary layer (ABL profiling. This study represents a proof-of-concept of RPAS observations in the Antarctic sea-ice zone. We present first results from the RV Polarstern Antarctic winter expedition in the Weddell Sea in June–August 2013, during which three RPAS were operated to measure temperature, humidity and wind; a fixed-wing small unmanned meteorological observer (SUMO, a fixed-wing meteorological mini-aerial vehicle, and an advanced mission and operation research quadcopter. A total of 86 RPAS flights showed a strongly varying ABL structure ranging from slightly unstable temperature stratification near the surface to conditions with strong surface-based temperature inversions. The RPAS observations supplement the regular upper air soundings and standard meteorological measurements made during the campaign. The SUMO and quadcopter temperature profiles agree very well and, excluding cases with strong temperature inversions, 70% of the variance in the difference between the SUMO and quadcopter temperature profiles can be explained by natural, temporal, temperature fluctuations. Strong temperature inversions cause the largest differences, which are induced by SUMO's high climb rates and slow sensor response. Under such conditions, the quadcopter, with its slower climb rate and faster sensor, is very useful in obtaining accurate temperature profiles in the lowest 100 m above the sea ice.

Small scale variability of snow properties on Antarctic sea ice

Science.gov (United States)

Wever, Nander; Leonard, Katherine; Paul, Stephan; Jacobi, Hans-Werner; Proksch, Martin; Lehning, Michael

2016-04-01

Snow on sea ice plays an important role in air-ice-sea interactions, as snow accumulation may for example increase the albedo. Snow is also able to smooth the ice surface, thereby reducing the surface roughness, while at the same time it may generate new roughness elements by interactions with the wind. Snow density is a key property in many processes, for example by influencing the thermal conductivity of the snow layer, radiative transfer inside the snow as well as the effects of aerodynamic forcing on the snowpack. By comparing snow density and grain size from snow pits and snow micro penetrometer (SMP) measurements, highly resolved density and grain size profiles were acquired during two subsequent cruises of the RV Polarstern in the Weddell Sea, Antarctica, between June and October 2013. During the first cruise, SMP measurements were done along two approximately 40 m transects with a horizontal resolution of approximately 30 cm. During the second cruise, one transect was made with approximately 7.5 m resolution over a distance of 500 m. Average snow densities are about 300 kg/m3, but the analysis also reveals a high spatial variability in snow density on sea ice in both horizontal and vertical direction, ranging from roughly 180 to 360 kg/m3. This variability is expressed by coherent snow structures over several meters. On the first cruise, the measurements were accompanied by terrestrial laser scanning (TLS) on an area of 50x50 m2. The comparison with the TLS data indicates that the spatial variability is exhibiting similar spatial patterns as deviations in surface topology. This suggests a strong influence from surface processes, for example wind, on the temporal development of density or grain size profiles. The fundamental relationship between variations in snow properties, surface roughness and changes therein as investigated in this study is interpreted with respect to large-scale ice movement and the mass balance.

Age and sex composition of seals killed by polar bears in the eastern Beaufort Sea.

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Nicholas W Pilfold

Full Text Available Polar bears (Ursus maritimus of the Beaufort Sea enter hyperphagia in spring and gain fat reserves to survive periods of low prey availability. We collected information on seals killed by polar bears (n=650 and hunting attempts on ringed seal (Pusa hispida lairs (n=1396 observed from a helicopter during polar bear mark-recapture studies in the eastern Beaufort Sea in spring in 1985-2011. We investigated how temporal shifts in ringed seal reproduction affect kill composition and the intraspecific vulnerabilities of ringed seals to polar bear predation.Polar bears primarily preyed on ringed seals (90.2% while bearded seals (Erignathus barbatus only comprised 9.8% of the kills, but 33% of the biomass. Adults comprised 43.6% (150/344 of the ringed seals killed, while their pups comprised 38.4% (132/344. Juvenile ringed seals were killed at the lowest proportion, comprising 18.0% (62/344 of the ringed seal kills. The proportion of ringed seal pups was highest between 2007-2011, in association with high ringed seal productivity. Half of the adult ringed seal kills were ≥ 21 years (60/121, and kill rates of adults increased following the peak of parturition. Determination of sex from DNA revealed that polar bears killed adult male and adult female ringed seals equally (0.50, n=78. The number of hunting attempts at ringed seal subnivean lair sites was positively correlated with the number of pup kills (r(2 =0.30, P=0.04, but was not correlated with the number of adult kills (P=0.37.Results are consistent with decadal trends in ringed seal productivity, with low numbers of pups killed by polar bears in spring in years of low pup productivity, and conversely when pup productivity was high. Vulnerability of adult ringed seals to predation increased in relation to reproductive activities and age, but not gender.

Absorption properties of chromophoric dissolved organic matter (CDOM) in the East China Sea and the waters off eastern Taiwan

Science.gov (United States)

Zhou, Fengxia; Gao, Xuelu; Song, Jinming; Chen, Chen-Tung Arthur; Yuan, Huamao; Xing, Qianguo

2018-05-01

The absorption properties of chromophoric dissolved organic matter (CDOM) in the East China Sea (ECS) and the waters off eastern Taiwan (WET) were studied during May 2014. CDOM absorption coefficient (a280) and spectral slope (S275-295) revealed considerable spatial variations. In the ECS, the values of a280 and S275-295 presented a reverse distribution pattern. In the WET, a280 values were generally low while S275-295 values were generally high. Vertical distributions of a280 and S275-295 also varied in different regions. Terrestrial input, phytoplankton production, sediment release or photobleaching may be responsible for the dynamics of CDOM. Relationships among CDOM related parameters could partly support this conclusion. a280 were also used to trace different water masses and the result showed that the influence of Changjiang Diluted Water could reach the outer shelf of the northern ECS, and that the Kuroshio Current had a strong influence on the middle shelf of the southern ECS.

Constraining back-arc basin formation in the eastern Coral Sea: preliminary results from the ECOSAT voyage

Science.gov (United States)

Seton, M.; Williams, S.; Mortimer, N. N.; Meffre, S.; Moore, J.; Micklethwaite, S.; Zahirovic, S.

2013-12-01

The eastern Coral Sea region is an underexplored area at the northeastern corner of the Australian plate, where long-lived interaction between the Pacific and Australian plate boundaries has resulted in an intricate assemblage of deep oceanic basins and ridges, continental fragments and volcanic products. A paucity of marine geophysical and geological data from this complex region has resulted in the lack of a clear conceptual framework to describe its formation, ultimately affecting our understanding of the connection between the plate boundaries of the SW Pacific and SE Asia. In particular, the tectonic relationship between two back-arc basins, the Santa Cruz and d'Entrecasteaux Basins, and the South Rennell Trough, has yet to be resolved. In October-November, 2012, we collected 6,200 km of marine magnetic, 6,800 km of gravity and over 13,600 km2 of swath bathymetry data from the eastern Coral Sea onboard the RV Southern Surveyor. A complementary dredging program yielded useful samples from 14 seafloor sites. Our preliminary geochemical interpretation of the dredge samples obtained from the South Rennell Trough reveal volcanic rocks resembling MORB or BABB-type basalts, similar in composition to the recently re-analysed and dated ORSTOM dredges from the area that yielded ~28 Ma MORB-like basalts. Swath bathymetry profiles from the Santa Cruz Basin reveal that the South Rennell Trough extends into this basin, with seafloor spreading fabric being parallel to the trough. Preliminary analysis of the three full and four partial new magnetic anomaly profiles across the Santa Cruz Basin, coupled with limited existing profiles, reveals that the basin may have formed between Chrons 13-18 (~32-38 Ma), with an extinct spreading ridge along the inferred continuation of the South Rennell Trough, consistent with ORSTOM age dates. Our results suggest that the South Rennell Trough is an extinct southwestward propagating spreading ridge, which may have initiated along a pre

Seasonal overturning circulation in the Red Sea: 2. Winter circulation

KAUST Repository

Yao, Fengchao

2014-04-01

The shallow winter overturning circulation in the Red Sea is studied using a 50 year high-resolution MITgcm (MIT general circulation model) simulation with realistic atmospheric forcing. The overturning circulation for a typical year, represented by 1980, and the climatological mean are analyzed using model output to delineate the three-dimensional structure and to investigate the underlying dynamical mechanisms. The horizontal model circulation in the winter of 1980 is dominated by energetic eddies. The climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24N. The overturning is accomplished through a cyclonic recirculation and a cross-basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model\\'s winter overturning circulation. The simulated water exchange is not hydraulically controlled in the Strait of Bab el Mandeb; instead, the exchange is limited by bottom and lateral boundary friction and, to a lesser extent, by interfacial friction due to the vertical viscosity at the interface between the inflow and the outflow. Key Points Sinking occurs in a narrow boundary layer along the eastern boundary Surface western boundary current switches into an eastern boundary current Water exchange in the Strait of Bab el Mandeb is not hydraulically controlled © 2014. American Geophysical Union. All Rights Reserved.

Vegetation Analysis in the Red Sea-Eastern Desert Ecotone at the Area between Safaga and South Qusseir, Egypt

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Mohamed G. Sheded

2014-12-01

Full Text Available The current work is concerned with the studying the impact of environmental conditions on the vegetation in the arid ecotone located between Red Sea and Eastern Desert from Safaga to south Qusseir. Ninety eight quadrats inside 13 transects were selected to cover the environmental gradient across the ecotone, from the coastal region to the boundary of Eastern Desert. Forty five species were recorded belonged to 24 different families and 38 genera. The perennial species were 38 while the annuals were seven species. Zygophyllum coccineum had the highest presence value (89.8% followed by Tamarix nilotica (56.1% and Zilla spinosa (51.02%. Chamaephytes and Hemicryptophytes were the most prevailed life-forms. Chrological analysis exhibited that SaharoSindian and Sahro-Sindian with its extension to Sudano-Zambezian elements were the most dominant. TWINSPAN classification technique produced three vegetation groups include nine clusters at the fourth level. These groups identified according to the first and second dominant species as follows: Convolvulus hystrix - Panicum turgidum, Tamarix aphylla - Limonium pruinosum and Nitraria retusa - Tamarix nilotica. DECORANA results indicated a reasonable segregation among these groups along the ordination axis 1 and 2. Vegetation analysis showed that ecotonal clusters have highest number of species/cluster, high species richness and high species turnover. Therefore, the largest group existed in the ecotone (34 species while the desert group contained eight species and the coastal group included three species. Among the estimated soil variables in this study, pH, coarse sand, HCO3-, SO42- , clay and PO43- have the highest effect on species distribution. Sodium adsorption ratio (SAR was the effective factor in detecting the ecotonal species, Aeluropus lagopoides and Limonium pruinosum.

Coastal Dunes of the Baltic Sea Shores: A Review

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Łabuz Tomasz Arkadiusz

2018-03-01

Full Text Available The article summarises results of studies conducted along the Baltic Sea sandy coasts by scientists involved in coastal dune research, and presents an attempt to describe the types and distribution of dune coasts. The Baltic Sea coasts feature lower and higher foredunes. The lowland behind the coastal dune belt is covered by wandering or stabilised inland dunes – transgressive forms, mainly parabolic or barchans. The source of sediment for dune development includes fluvioglacial sands from eroded coasts, river-discharged sand, and older eroded dunes. Due to the ongoing erosion and coastal retreat, many dunes have been eroded, and some are withdrawing onto the adjacent land. There are visible differences between the south-eastern, western, and northern parts of the Baltic Sea coast with respect to dune development. The entire southern and eastern coast abounds in sand, so the coastal dunes are large, formerly or currently wandering formations. The only shifting dunes are found at the Polish and the Russian–Lithuanian coasts on the Łebsko Lake Sandbar as well as on the Vistula and Curonian Spits. The very diverse shoreline of the south-western coast experiences a scarcity of larger sandy formations. Substantial parts of the Baltic Sea sandy coasts have been eroded or transformed by humans. The northern part of the Baltic Sea coast features mainly narrow and low sandy coasts (e.g. in Estonia. Further north, sandy dunes are virtually absent.

Quantitative estimation of massive gas hydrate in gas chimney structures, the eastern margin of Japan Sea, from the physical property anomalies obtained by LWD.

Science.gov (United States)

Tanahashi, M.; Morita, S.; Matsumoto, R.

2017-12-01

Two dedicated LWD (Logging While Drilling) cruises, GR14 and HR15, were conducted in summers of 2014 and 2015, respectively, by Meiji University and Geological Survey of Japan, AIST to explore the gas chimney structures, which are characterized by the columnar acoustic blanking below the topographic mound and/or pockmarks in eastern margin of Japan Sea. Shallow (33 to 172m-bsf, average 136m-bsf) 33 LWD drillings were carried out generally in and around gas chimney structures which are in Oki Trough, Off-Joetsu, and Mogami Trough areas, eastern margin of Japan Sea, during two cruises. Schlumberger LWD tools, GeoVISION (resistivity), TeleScope, ProVISION (NMR) and SonicVISION (sonic) were applied during GR14. NeoScope (neutron) was added and SonicScope was replaced for SonicVISION during HR15. The presence of thick highly-anomalous intervals within the LWD data at site J24L suggests the development of massive gas hydrate within Off-Joetsu, by very high resistivity ( 10,000 Ωm), high Vp ( 3,700 m/s) and Vs (370-1,839 m/s), high neutron porosity ( 1.2), low natural gamma ray intensity ( 0 API), low neutron gamma density ( 0.8 g/cm3), low NMR porosity ( 0.0), low permeability (10-2-10-4 mD), low formation neutron sigma (26-28). The extreme physical properties intervals suggest the development of the almost pure hydrate. Because of the clear contrast between pure hydrate and seawater saturated fine sediments, the hydrate amount can be estimated quantitatively based on the assumptions as the two component system of pure hydrate and the monotonous seawater saturated fine sediments. This study was conducted as a part of the methane hydrate research project funded by METI (the Ministry of Economy, Trade and Industry, Japan).

DDT residues in fishes from the eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Shailaja, M.S.; SenGupta, R.

degrees E) were obtained from the commercial jetty within 2 h of landing while those from the open sea (16 degrees 30'N 69 degrees E-19 degrees 30'N 67 degrees E) such as Tylosurus sp. (longtom), Coryphaena hippurus (dolphin fish), Loligo sp. (squid...

Review of past and present geotectonic concepts of eastern indonesia

Science.gov (United States)

Katili, John A.

equatorial Indo-Pacific region, for example, has recently been compared to the terrane map of the North American Cordillera. The position of eastern Indonesia within the plate-tectonic framework is the key to resolving contradictory views on the tectonics of the Banda Sea. For example, did the Indonesian orogeny take place at the Gondwana margin or the Asian margin, are Timor and Seram a tectonic melange and thus part of the Tertiary Indonesian island arcs, or are these two islands a part of the passive Australian margin? Oceanic magnetic stripes from the Sulu, Celebes and Banda Seas all trend NE-SW. These new data suggest that the Sulu, Celebes and probably the Banda Sea represent areas of trapped Indian Ocean crust. Deep sea drilling in the Banda Sea can resolve much controversy. The Banda Sea occupies a critical position in the complex convergent zone between Australia, Southeast Asia and the Philippine Sea Plate. The determination of the stratigraphy and basement ages of the Banda Sea will constrain evolutionary models which have been proposed. Another unsolved question of key importance in our understanding of the evolution of Sulawesi and the Moluccas is the function and timing of events of the Birdhead 'bacon slicer', or the tectonic shaving in Irian Jaya. Once this mechanism is understood, the development and timing of the various structural features of Sulawesi, Halmahera and the Banda Arc will be classified. Opinions still differ regarding the 'birthplace' of the micro-continents in the Banda Sea. Some regard them as a result of Jurassic rifting of Gondwana in northwestern Australia while others consider them displaced westward from northern Irian Jaya along the Sorong transform fault. Several authors suggested that the eastern parts of Sulawesi, Buru and Seram represent micro-continents which originated from Irian Jaya, while others considered East Sulawesi and north Sulawesi remnants of ophiolite belts or fragments of island arcs that originate from the Pacific

Anti-inflammatory activity in selected Antarctic benthic organisms

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Juan eMoles

2014-07-01

Full Text Available Antarctic benthos was prospected in search for anti-inflammatory activity in polar benthic invertebrates, in two different geographical areas: deep-bottoms of the Eastern Weddell Sea and shallow-waters of the South Shetland Islands. A total of 36 benthic algae and invertebrate species were selected to perform solubility tests in order to test them for anti-inflammatory activity. From these, ethanol extracts of ten species from five different phyla resulted suitable to be studied in cell macrophage cultures (RAW 264.7. Cytotoxicity (MTT method and production of inflammatory mediators (prostaglandin E2, leukotriene B4, interleukin-1 were determined at three extract concentrations (50, 125, 250 g/mL. Bioassays resulted in four different species showing anti-inflammatory activity corresponding to three sponges: Mycale (Oxymycale acerata, Isodictya erinacea, and I. toxophila; and one hemichordate: Cephalodiscus sp. These results show that Antarctic sessile invertebrates may have great value as a source of lead compounds with potential pharmaceutical applications.

Coccolithophorids in polar waters: Pappomonas spp. revisited

DEFF Research Database (Denmark)

Thomsen, Helge Abildhauge; Østergaard, J.B.

2014-01-01

virgulosa HOL (= Balaniger balticus phase). A new species, Pappomonas garrisonii sp. nov. is described to accommodate Antarctic material from the Wed-dell Sea. While ftting into the Pappomonas generic concept, the species adds new dimensions to the overall appearance of the coccolith armour of the cell...

CHEMTAX-derived phytoplankton community structure associated with temperature fronts in the northeastern Arabian Sea..

Digital Repository Service at National Institute of Oceanography (India)

Roy, R; Chitari, R; Kulkarni, V.; Krishna, M.S.; Sarma, V.V.S.S.; Anil, A.C.

and northern Arabian Sea. Deep-Sea Res. I 34, 713-723. Barlow, R., Kyewalyanga, M., Sessions, H., Van den Berg, M., Morris, T., 2008. Phytoplankton pigments, functional types, and absorption properties in the Delagoa and Natal Bights of the Agulhas... for Prochlorococcus sp. in low-light suboxic environments in the Arabian Sea and the Eastern Tropical North Pacific. Deep-Sea Res. I. 47, 1183-1205. Grasshoff, K., Erhardt, M., Kremiling, K., 1983. Methods of seawater analysis, Verlag Chemie. 419 Haynes, R...

Past and present Aral Sea

Science.gov (United States)

Dukhovniy, Viktor; Stulina, Galina; Eshchanov, Odylbek

2013-04-01

any more (1980-1990). Kokaral was the first of the large islands becoming a peninsula, separating the Small Aral Sea in the north-east by joining the shoreline in the west. By 1986, the peninsula practically detached the small Aral Sea from the large Aral Sea, leaving only a narrow flow passage in the east. Since that time, the hydrological regimes of the Small and Large Seas have become separated. The construction of Kokaral dam in Kazakhstan, 12 km long and 8 m high, then completely separated the small Aral Sea from the large Aral Sea and changed the hydrological regimes of the water bodies. Level of this part of Sea became from this moment permanently higher than in the large Aral Sea on 42 m a.s.l. The eastern part of the sea, where the bed is much shallower and the slope is gentler is more subjected to shrinking then the western part. 2005 year became threshold, from which Eastern Aral Sea began new story - deviation from almost empty water body to almost 4 meters depth. Present assessment of water balance of Aral Sea and delta at whole dependent from delivery water river and drainage flow through control section of Samanbay on the Amudarya and some cross sections on the enter main collectors to the delta boundary. These hydrological characteristics accepted on the base of information from BWO Amudarya and our monitoring of allocation of different waters on the delta. Water volume and water surface area of Eastern and Western Aral Sea bowls were definite on the result RS data from Landsat. Bathymetric curves gave ability to assess dynamic levels of Seas. After series of enough water years 2002 - 2005 with average water income to south Priaralie 12.5 km3 period of water scarce years lead to sharp decrease of surface water area of the Eastern bowl from 1010,5 th.ha on average on two time with failure of level from 31,1 m up to average 28,5 m. But phase of permanent reducing all indicators water body changed in 2008 on deviation in range from 26.3 m to 29.5 m. Some

Shear-controlled evolution of the Red Sea: pull apart model

Science.gov (United States)

Makris, J.; Rihm, R.

1991-11-01

Results of seismic and other geophysical investigations suggest that strike-slip processes controlled the break-up of the Arabian plate from Africa and initiated the Red Sea Rift. Early oceanisation was facilitated by nucleation of pull apart basins and massive intrusives. The evolution of the Red Sea has gone through different stages. It was a zone of structural weakness already during the Pan-African orogeny approximately 600 Ma. A major reactivation, however, that gradually led to the present-day configuration was initiated during the late Oligocene with intense magmatic activity and the development of a continental rift. Wrench faulting played a key role in the early evolution of the Red Sea, as it shaped most of its western flank as a sharp plate boundary and resulted in the generation and rapid oceanisation of linearly arranged pull apart basins. Spatial distribution of these basins reflects the geometry of the strike-slip zone, which was controlled by pre-existing fault systems like the Najd Shear System, the Central African Fault Zone or the Onib-Hamisana and Baraka suture zones. Strike-slip motion along the latter zones of weakness influenced mainly the Egyptian and Sudanese coastal areas. Arabia was therefore separated from Africa by oceanisation in those regions, where pull apart basins developed. They were still connected in the in-between segments by stretched continental crust. With Arabia as the "moving" and Africa as the "stable" plate the eastern Red Sea flank was formed by pure shear through stretching, thinning and diffuse extension. As a consequence, the eastern and western flanks of the Red Sea are asymmetrical. The acceleration of the movement of Arabia in early/middle Miocene could no longer be accommodated by the opening in the Gulf of Suez and consequently the Dead Sea strike-slip fault developed approximately 14 Ma ago. Since plate motion was still oblique to the major structural trends, the pull apart evolution on the western flank

Flow Patterns in the Eastern Chukchi Sea: 2010-2015

Science.gov (United States)

Stabeno, Phyllis; Kachel, Nancy; Ladd, Carol; Woodgate, Rebecca

2018-02-01

From 2010 to 2015, moorings were deployed on the northern Chukchi Sea at nine sites. Deployment duration varied from 5 years at a site off Icy Cape to 1 year at a site north of Hanna Shoal. In addition, 39 satellite-tracked drifters (drogue depth 25-30 m) were deployed in the region during 2012-2015. The goals of this manuscript are to describe currents in the Chukchi Sea and their relationship to ice and winds. The north-south pressure gradient results in, on average, a northward flow over the Chukchi shelf, which is modified by local winds. The volume transport near Icy Cape (˜0.4 Sv) was ˜40% of flow through Bering Strait and varied seasonally, accounting for >50% of summer and ˜20% of winter transport in Bering Strait. Current direction was strongly influenced by bathymetry, with northward flow through the Central Channel and eastward flow south of Hanna Shoal. The latter joined the coastal flow exiting the shelf via Barrow Canyon. Drifter trajectories indicated the transit from Bering Strait to the mouth of Barrow Canyon took ˜90 days during the ice-free season. Most (˜70%) of the drifters turned westward at the mouth of Barrow Canyon and continued westward in the Chukchi Slope Current. This slope flow was largely confined to the upper 300 m, and although it existed year-round, it was strongest in spring and summer. Drifter trajectories indicated that the Chukchi Slope Current extends as far west as the mouth of Herald Canyon. The remaining ˜30% of the drifters turned eastward or were intercepted by sea ice.

Seasonal and interannual variations in pigments in the Adriatic Sea

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

30m), depends on the freshwater inflow as well ... The Adriatic Sea (Northern Mediterranean) and location of satellite pigment data (cross marks) ..... landings of small pelagic fish in the eastern Adriatic– ... and North America (1858–1980).

Patterns in connectivity and retention of simulated Tanner crab (Chionoecetes bairdi) larvae in the eastern Bering Sea

Science.gov (United States)

Richar, Jonathan I.; Kruse, Gordon H.; Curchitser, Enrique; Hermann, Albert J.

2015-11-01

The eastern Bering Sea (EBS) population of Tanner crab (Chionoecetes bairdi) has exhibited high variability in recruitment to the commercially exploited stock since the late 1970s. Concurrently, apparent shifts in crab distribution have also been observed. Larval advection patterns and associated local retention offer a potential mechanism for these observations. The Regional Ocean Modeling System (ROMS) was used to simulate larval Tanner crab advection patterns over 1978-2004 based on larval hatching sites inferred from the distributions of reproductive females sampled during annual National Marine Fisheries Service trawl surveys. Connectivity among EBS subregions was examined by comparing start and end float locations after 60 days of simulated drift. High levels of retention (>50% of floats) were observed in the majority of source subregions, and contributed significantly to the total number of endpoints in each region. Patterns in advection and resultant interregional connectivity were variable, with strongest sustained connectivity occurring along shelf, within individual domains. Increased settlement potential in the outer domain and southern middle domain after 1990 is consistent with an observed geographic shift in fishery productivity. Apparent reliance of Bristol Bay on local larval retention validates recent spatial fishery management to conserve this area as a subpopulation.

A cold pool south of Indo-Sri Lanka channel and its intrus on into the southeastern Arabian Sea during winter

Digital Repository Service at National Institute of Oceanography (India)

Rao, R.R.; GirishKumar, M.S.; Ravichandran, M.; Gopalakrishna, V.V.; Pankajakshan, T.

northwestward by the Maldives Island Chain. The resultant near-surface circulation also appears to strengthen the amplitude of the near-surface thermal inversions observed in the SouthEastern Arabian Sea (SEAS)...

Mesostructural observations along the Western coast of Bel'kovsky Island: preliminary results (North-Eastern Laptev Sea region, Russian Arctic)

Science.gov (United States)

Verzhbitsky, V. E.

2003-04-01

This study is based on the field works carried out by the Institute of the Lithosphere of Marginal Seas RAS in the central part of the Bel'kovsky island during 2002 August-September. In the tectonic sense the Bel'kovsky island is located in the eastern part of the Late Cretaceous (?) - Cenozoic Laptev Sea rift system and also is a part of extended Bel’kov horst, dividing Bel’kov Svyatoi Nos (in the east) and Anisin (in the west) rifts (e.g. Drachev et al, 1998). Mesostructural investigations included statistical measurments of kinematic indicators (cleavage planes, extensional veins, slickensides, axes of folds and bedding plains) in Devonian and Carboniferous sedimentary formations and also slickensides in diabase magmatic complex (presumably of Late Paleozoic age). It is supposed, that this studies will allow to characterize the stages of regional tectonic processes: synsedimentary (slump) folds formation (1), NE-SW compression (2), which corresponds to the general (NW-SE trending) structural pattern of the island, E-W compression (3), expressed in N-S trending subvertical cleavage and associated strike-slips and thrust faults, NW-SE (4) and ENE-WSW - NE-SW (5) extension, expressed in strike-slip faults with different strike-slip component, and also, probably to specify the character of the recent tectonic processes near to the area of conjunction between the Eurasian and American plates. It is likely, that synsedimentary (slump) folds, identified in the Carboniferous clastic formation marks the paleoslope setting of New Siberian Islands Chukotka platform (block). Presumably, second of the determined stages corresponds to closing of the South Anyui Lyakhov paleooceanic basin in Neocomian; the last stage, expressed in wide-developed submeridional normal faults with sinistral strike-slip component along the western coast of the island, reflects the modern regional stress-field in area of conjunction between the Eurasian and American plates (e.g. Avetisov, 1999

Circulation in the Mediterranean Sea: evidences, debates and unanswered questions

Directory of Open Access Journals (Sweden)

Claude Millot

2005-06-01

Full Text Available The overall counterclockwise alongslope circulation of Atlantic Water (AW in the western basin of the Mediterranean Sea is now generally accepted. As the eastern basin displays similar general features, why is it generally assumed to function in a different way, and why is AW now said to circulate across the interior of the eastern basin? Relatively huge mesoscale anticyclonic eddies induced by the instability of the AW circulation in the south of the western basin have lifetimes up to several years. It is possible that they extend down to the sea bottom and play a major role in the distribution of all water masses. Why have apparently similar eddies generated in the eastern basin never received specific attention? Once formed, Mediterranean Waters (MWs must spread and circulate before outflowing. Why have simple dynamical arguments for understanding the circulation of AW, such as the Coriolis effect, rarely been considered for the circulation of MWs? In this paper we address these major aspects of water circulation in the Mediterranean Sea. In order to be as objective and convincing as possible, and to write a paper that can be understood by as broad a readership as possible, we have chosen to present only raw data sets that can be easily interpreted by the reader without any help from the author. Based on the evidence provided by these data sets, we specify the current debates and list what we think are the main unanswered questions.

Mass-induced sea level variations in the Red Sea from steric-corrected altimetry, GRACE, in-situ bottom pressure records, and hydrographic observations

Science.gov (United States)

Feng, Wei; Lemoine, Jean-Michel; Zhong, Min; Xu, Houze

2014-05-01

An annual amplitude of ~18 cm mass-induced sea level variations (SLV) in the Red Sea is detected from steric-corrected altimetry and the Gravity Recovery and Climate Experiment (GRACE) satellites from 2003 to 2011, which dominates the mean sea level in the region. Seawater mass variations here generally reach maximum in late January/early February. The steric component of SLV calculated from oceanographic temperature and salinity data is relatively small and peaks about seven months later than mass variations. The phase difference between the steric SLV and the mass-induced SLV indicates that when the Red Sea gains the mass from inflow water in winter, the steric SLV fall, and vice versa in summer. In-situ bottom pressure records in the eastern coast of the Red Sea validate the high mass variability observed by steric-corrected altimetry and GRACE. Furthermore, we compare the horizontal water mass flux in the Red Sea from steric-corrected altimetry and GRACE with that estimated from hydrographic observations.

Distribution of Thyroid Cancer in the Eastern Part of Turkey 27 Years After the Chernobyl Accident.

Science.gov (United States)

Sahin, Serap Baydur; Yucel, Ahmet Fikret; Gucer, Hasan; Pergel, Ahmet; Bedir, Recep; Aydin, Ibrahim; Sehitoglu, Ibrahim; Sahin, Dursun Ali; Sahin, Osman Zikrullah

2013-12-01

The Chernobyl accident caused widespread effects across Europe and huge areas where radiocontaminated. The effects of the Chernobyl accident on thyroid cancer have been investigated in most European countries. According to the data of the Turkish Atomic Energy Authority, the eastern part of the Black Sea region was the most radiocontaminated area in Turkey at the time of Chernobyl accident. We therefore aimed to examine the data of thyroid cancers at our center, Rize city which is located in the eastern Black Sea region. This retrospective study included the patients with histologically proven thyroid cancer at our center between January 2008 and May 2012. Pathologic examinations of thyroidectomy materials were reviewed. We evaluated patients' age, gender, size of the primary tumor (all sizes, Chernobyl accident.

The biodiversity of the Mediterranean Sea: estimates, patterns, and threats.

Directory of Open Access Journals (Sweden)

Marta Coll

Full Text Available The Mediterranean Sea is a marine biodiversity hot spot. Here we combined an extensive literature analysis with expert opinions to update publicly available estimates of major taxa in this marine ecosystem and to revise and update several species lists. We also assessed overall spatial and temporal patterns of species diversity and identified major changes and threats. Our results listed approximately 17,000 marine species occurring in the Mediterranean Sea. However, our estimates of marine diversity are still incomplete as yet-undescribed species will be added in the future. Diversity for microbes is substantially underestimated, and the deep-sea areas and portions of the southern and eastern region are still poorly known. In addition, the invasion of alien species is a crucial factor that will continue to change the biodiversity of the Mediterranean, mainly in its eastern basin that can spread rapidly northwards and westwards due to the warming of the Mediterranean Sea. Spatial patterns showed a general decrease in biodiversity from northwestern to southeastern regions following a gradient of production, with some exceptions and caution due to gaps in our knowledge of the biota along the southern and eastern rims. Biodiversity was also generally higher in coastal areas and continental shelves, and decreases with depth. Temporal trends indicated that overexploitation and habitat loss have been the main human drivers of historical changes in biodiversity. At present, habitat loss and degradation, followed by fishing impacts, pollution, climate change, eutrophication, and the establishment of alien species are the most important threats and affect the greatest number of taxonomic groups. All these impacts are expected to grow in importance in the future, especially climate change and habitat degradation. The spatial identification of hot spots highlighted the ecological importance of most of the western Mediterranean shelves (and in particular

The biodiversity of the Mediterranean Sea: estimates, patterns, and threats.

Science.gov (United States)

Coll, Marta; Piroddi, Chiara; Steenbeek, Jeroen; Kaschner, Kristin; Ben Rais Lasram, Frida; Aguzzi, Jacopo; Ballesteros, Enric; Bianchi, Carlo Nike; Corbera, Jordi; Dailianis, Thanos; Danovaro, Roberto; Estrada, Marta; Froglia, Carlo; Galil, Bella S; Gasol, Josep M; Gertwagen, Ruthy; Gil, João; Guilhaumon, François; Kesner-Reyes, Kathleen; Kitsos, Miltiadis-Spyridon; Koukouras, Athanasios; Lampadariou, Nikolaos; Laxamana, Elijah; López-Fé de la Cuadra, Carlos M; Lotze, Heike K; Martin, Daniel; Mouillot, David; Oro, Daniel; Raicevich, Sasa; Rius-Barile, Josephine; Saiz-Salinas, Jose Ignacio; San Vicente, Carles; Somot, Samuel; Templado, José; Turon, Xavier; Vafidis, Dimitris; Villanueva, Roger; Voultsiadou, Eleni

2010-08-02

The Mediterranean Sea is a marine biodiversity hot spot. Here we combined an extensive literature analysis with expert opinions to update publicly available estimates of major taxa in this marine ecosystem and to revise and update several species lists. We also assessed overall spatial and temporal patterns of species diversity and identified major changes and threats. Our results listed approximately 17,000 marine species occurring in the Mediterranean Sea. However, our estimates of marine diversity are still incomplete as yet-undescribed species will be added in the future. Diversity for microbes is substantially underestimated, and the deep-sea areas and portions of the southern and eastern region are still poorly known. In addition, the invasion of alien species is a crucial factor that will continue to change the biodiversity of the Mediterranean, mainly in its eastern basin that can spread rapidly northwards and westwards due to the warming of the Mediterranean Sea. Spatial patterns showed a general decrease in biodiversity from northwestern to southeastern regions following a gradient of production, with some exceptions and caution due to gaps in our knowledge of the biota along the southern and eastern rims. Biodiversity was also generally higher in coastal areas and continental shelves, and decreases with depth. Temporal trends indicated that overexploitation and habitat loss have been the main human drivers of historical changes in biodiversity. At present, habitat loss and degradation, followed by fishing impacts, pollution, climate change, eutrophication, and the establishment of alien species are the most important threats and affect the greatest number of taxonomic groups. All these impacts are expected to grow in importance in the future, especially climate change and habitat degradation. The spatial identification of hot spots highlighted the ecological importance of most of the western Mediterranean shelves (and in particular, the Strait of

Red to Mediterranean Sea bioinvasion: natural drift through the Suez Canal, or anthropogenic transport?

Science.gov (United States)

Shefer, Sigal; Abelson, Avigdor; Mokady, Ofer; Geffen, Eli

2004-08-01

The biota of the eastern basin of the Mediterranean Sea has experienced dramatic changes in the last decades, in part as a result of the massive invasion of Red Sea species. The mechanism generally hypothesized for the 'Red-to-Med' invasion is that of natural dispersal through the Suez Canal. To date, however, this hypothesis has not been tested. This study examines the mode of invasion, using as a model the mussel Brachidontes pharaonis, an acclaimed 'Lessepsian migrant' that thrives along the eastern Mediterranean coast. Our findings reveal two distinct lineages of haplotypes, and five possible explanations are discussed for this observation. We show that the genetic exchange among the Mediterranean, Gulf of Suez and the northern Red Sea is sufficiently large to counteract the build up of sequential genetic structure. Nevertheless, these basins are rich in unique haplotypes of unknown origin. We propose that it is historic secondary contact, an ongoing anthropogenic transport or both processes, that participate in driving the population dynamics of B. pharaonis in the Mediterranean and northern Red Sea. Copyright 2004 Blackwell Publishing Ltd

Mesopelagic Prokaryotes Alter Surface Phytoplankton Production during Simulated Deep Mixing Experiments in Eastern Mediterranean Sea Waters

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Or Hazan

2018-01-01

Full Text Available Mesopelagic prokaryotes (archaea and bacteria, which are transported together with nutrient-rich intermediate-water to the surface layer by deep convection in the oceans (e.g., winter mixing, upwelling systems, can interact with surface microbial populations. This interaction can potentially affect production rates and biomass of surface microbial populations, and thus play an important role in the marine carbon cycle and oceanic carbon sequestration. The Eastern Mediterranean Sea (EMS is one of the most oligotrophic and warm systems in the world's oceans, with usually very shallow winter mixing (<200 m and lack of large-size spring algal blooms. In this study, we collected seawater (0–1,500 m in 9 different cruises at the open EMS during both the stratified and the mixed seasons. We show that the EMS is a highly oligotrophic regime, resulting in low autotrophic biomass and primary productivity and relatively high heterotrophic prokaryotic biomass and production. Further, we simulated deep water mixing in on-board microcosms using Levantine surface (LSW, ~0.5 m and intermediate (LIW, ~400 m waters at a 9:1 ratio, respectively and examined the responses of the microbial populations to such a scenario. We hypothesized that the LIW, being nutrient-rich (e.g., N, P and a “hot-spot” for microbial activity (due to the warm conditions that prevail in these depths, may supply the LSW with not only key-limiting nutrients but also with viable and active heterotrophic prokaryotes that can interact with the ambient surface microbial population. Indeed, we show that LIW heterotrophic prokaryotes negatively affected the surface phytoplankton populations, resulting in lower chlorophyll-a levels and primary production rates. This may be due to out-competition of phytoplankton by LIW populations for resources and/or by a phytoplankton cell lysis via viral infection. Our results suggest that phytoplankton in the EMS may not likely form blooms, even after

Comparative Reproduction Aspects of the Deep-water Shrimps Aristaeomorpha foliacea and Aristeus antennatus (Decapoda, Aristeidae in the Greek Ionian Sea (Eastern Mediterranean

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K. Kapiris

2009-01-01

Full Text Available In the eastern Ionian Sea, the deep-water shrimps Aristaeomorpha foliacea and Aristeus antennatus constitute a virgin fishing resource, since their maximum abundance depth exceeds commercial exploitation depths. The two sympatric species share a number of common reproductive features, such as summer reproduction. A slight temporal shift in mating activity, ovarian maturation, and spawning period was observed between species. The most notable difference was the more pronounced seasonality in reproductive activity of Aristeus antennatus compared to that of A. foliacea as evidenced by the frequency of inseminated females and functionally mature males, as well as by the shorter ovarian maturation period. Nevertheless, regarding the whole life span, both sexes of Aristeus antennatus exhibit a more extended reproductive activity in comparison to A. foliacea. No notable differentiation of both species existed in comparison to other Mediterranean regions.

Aerosol direct effect on solar radiation over the eastern Mediterranean Sea based on AVHRR satellite measurements

Science.gov (United States)

Georgakaki, Paraskevi; Papadimas, Christos D.; Hatzianastassiou, Nikos; Fotiadi, Aggeliki; Matsoukas, Christos; Stackhouse, Paul; Kanakidou, Maria; Vardavas, Ilias M.

2017-04-01

Despite the improved scientific understanding of the direct effect of aerosols on solar radiation (direct radiative effect, DRE) improvements are necessary, for example regarding the accuracy of the magnitude of estimated DREs and their spatial and temporal variability. This variability cannot be ensured by in-situ surface and airborne measurements, while it is also relatively difficult to capture through satellite observations. This becomes even more difficult when complete spatial coverage of extended areas is required, especially concerning areas that host various aerosol types with variable physico-chemical and optical aerosol properties. Better assessments of aerosol DREs are necessary, relying on aerosol optical properties with high spatial and temporal variation. The present study aims to provide a refined, along these lines, assessment of aerosol DREs over the eastern Mediterranean (EM) Sea, which is a key area for aerosol studies. Daily DREs are computed for 1˚ x1˚ latitude-longitude grids with the FORTH detailed spectral radiation transfer model (RTM) using input data for various atmospheric and surface parameters, such as clouds, water vapor, ozone and surface albedo, taken from the NASA-Langley Global Earth Observing System (GEOS) database. The model spectral aerosol optical depth (AOD), single scattering albedo and asymmetry parameter are taken from the Global Aerosol Data Set and the NOAA Climate Data Record (CDR) version 2 of Advanced Very High resolution Radiometer (AVHRR) AOD dataset which is available over oceans at 0.63 microns and at 0.1˚ x0.1˚ . The aerosol DREs are computed at the surface, the top-of-atmosphere and within the atmosphere, over the period 1985-1995. Preliminary model results for the period 1990-1993 reveal a significant spatial and temporal variability of DREs over the EM Sea, for example larger values over the Aegean and Black Seas, surrounded by land areas with significant anthropogenic aerosol sources, and over the

A laboratory and field study of 210Po depuration by edible winkles (Littorina littorea L.) from the Cumbrian coast (north-eastern Irish Sea)

International Nuclear Information System (INIS)

Swift, D.J.; Smith, D.L.; Allington, D.J.; Winpenny, K.

1995-01-01

Edible winkles from Saltom Bay, Cumbria (north-eastern Irish Sea) had flesh 210 Po concentrations in excess of 200 Bq kg -1 (wet). This came from liquid waste discharged under authorisation from a chemical plant producing phosphoric acid. This labelling of the winkles under natural conditions was exploited to determine the 210 Po depuration rate and biological half-time. Winkles transferred to Lowestoft and depurated in flowing seawater had biological half-times ranging from 82 to 119 days depending on temperature. After the chemical plant was shut, changes in Saltom Bay winkle flesh contents of 210 Po, 210 Pb and cadmium were followed by monthly samples. The biological half-time in the environment for the decrease in 210 Po after the plant closed was estimated at about 92 days. (author)

The biodiversity and biogeography of komokiaceans and other enigmatic foraminiferan-like protists in the deep Southern Ocean

DEFF Research Database (Denmark)

Gooday, A.J.; Cedhagen, Tomas; Kamenskaya, O.E.

2007-01-01

We present a survey of komokiaceans and other relatively large, stercomata-bearing testate protists, presumed to be foraminifera, based on extensive ship-board sorting of samples collected at 13 sites (depth range 1820-4930 m) in the Weddell Sea and two sites in the SE Atlantic (Cape and Aguilas...

New Observations of the Gulf of Aden Intermediate Water Intrusion into the Red Sea.

Science.gov (United States)

Bower, A.; Abualnaja, Y.

2012-04-01

The three-layer exchange flow between the Red Sea and the Indian Ocean during summer is characterized by a thick, northward intrusion of relatively cold, low-salinity and low in dissolved oxygen (Water (GAIW), sandwiched between two thin layers of outflow water. The flux of GAIW into the Red Sea is important in the heat, freshwater and nutrient budgets of the Red Sea, but the structure and pathways of the intrusion are not well-known due to a paucity of hydrographic and direct velocity observations. A research cruise was executed at the eastern side of the Red Sea during September-October 2011 to conduct the first large-scale survey of the intrusion. This mission is part of a series of expeditions in the Red Sea designed to investigate the seasonal Red Sea circulation. Surprisingly, the GAIW intrusion was observed to stretch nearly the entire length of the Red Sea (~1500 km) as a narrow eastern boundary current with subsurface velocity maximum of 0.1-0.3 m/s in the depth range 50-100 m. The intruding layer is weakly stratified compared to the background, possibly an indication of strong vertical mixing as it flows through the strait. Some GAIW was observed to enter deep channels in a coral reef bank (Farasan Banks) located in the southeastern Red Sea, and to enter the Red Sea interior, the latter possibly due to interactions between the boundary current and mesoscale eddies. The pathways and erosion of the GAIW intrusion will likely have major implications for the spatial distribution of biological productivity.

Predictability of summer extreme precipitation days over eastern China

Science.gov (United States)

Li, Juan; Wang, Bin

2017-08-01

Extreme precipitation events have severe impacts on human activity and natural environment, but prediction of extreme precipitation events remains a considerable challenge. The present study aims to explore the sources of predictability and to estimate the predictability of the summer extreme precipitation days (EPDs) over eastern China. Based on the region- and season-dependent variability of EPDs, all stations over eastern China are divided into two domains: South China (SC) and northern China (NC). Two domain-averaged EPDs indices during their local high EPDs seasons (May-June for SC and July-August for NC) are therefore defined. The simultaneous lower boundary anomalies associated with each EPDs index are examined, and we find: (a) the increased EPDs over SC are related to a rapid decaying El Nino and controlled by Philippine Sea anticyclone anomalies in May-June; (b) the increased EPDs over NC are accompanied by a developing La Nina and anomalous zonal sea level pressure contrast between the western North Pacific subtropical high and East Asian low in July-August. Tracking back the origins of these boundary anomalies, one or two physically meaningful predictors are detected for each regional EPDs index. The causative relationships between the predictors and the corresponding EPDs over each region are discussed using lead-lag correlation analyses. Using these selected predictors, a set of Physics-based Empirical models is derived. The 13-year (2001-2013) independent forecast shows significant temporal correlation skills of 0.60 and 0.74 for the EPDs index of SC and NC, respectively, providing an estimation of the predictability for summer EPDs over eastern China.

Long-range atmospheric transport of pollutants to the Eastern Mediterranean basin

International Nuclear Information System (INIS)

Tuncel, G.; Tuncel, S.

1994-01-01

A permanent stations has been established in the Eastern Mediterranean coast of Turkey for continuous monitoring of aerosols and precipitation. The station is part of the MED-POL programme which includes all countries that have coasts in the Mediterranean Sea and attempts to determine the role of the atmospheric fluxes of pollutants on the pollution of the Mediterranea Sea. Aerosol and deposition samples have been collected since early 1992. Concentrations of SO 4 , NO 3 , Cl, Li, Pb, K, Ca, Al, As, Cd, Cr, Cu, Se, Zn and Na were determined by ion chromatography and atomic absorption spectrometry. Daily samples will be screened to select the ones which correspond to transport from Europe and will be analyzed for a larger number of parameters using INAA. Method development took most of the time in 1992, and analysis are still in progress. Available data have shown that concentrations of anthropogenic elements are smaller in the Eastern Mediterranean atmosphere compared to other rural sites in the Europe. (author). 21 refs, 8 figs, 6 tabs

Application of isostatic gravity anomaly in the Yellow Sea area

Science.gov (United States)

Hao, Z.; Qin, J.; Huang, W.; Wu, X.

2017-12-01

In order to study the deep crustal structure of the Yellow Sea area, we used the Airy-Heiskanen model to calculate the isostatic gravity anomaly of this area. Based on the Bouguer gravity anomaly and water depth data of this area, we chose the calculating parameters as standard crustal thickness 30 km, crust-mantle density difference 0.6g/cm3and grid spacing 0.1°×0.1°. This study reveals that there are six faults and four isostatic negative anomalies in the study area. The isostatic anomalies in much of Yellow Sea areas give priority to those with positive anomalies. The isostatic anomalies in North Yellow Sea are higher than South Yellow Sea with Jiashan-Xiangshui fault as the boundary. In the north of the study area, isostatic anomalies are characterized by large areas of positive anomaly. The change is relatively slow, and the trends give priority to the trend NE or NEE. In the middle of the north Yellow Sea basin, there is a local negative anomaly, arranged as a string of beads in NE to discontinuous distribution. Negative anomaly range is small, basically corresponds to the region's former Cenozoic sedimentary basin position. To the south of Jiashan-Xiangshui fault and west of Yellow Sea eastern margin fault, including most of the south Yellow Sea and Jiangsu province, the isostatic anomalies are lower. And the positive and negative anomalies are alternative distribution, and negative anomaly trap in extensive development. The trends give priority to NE, NEE, both to the NW. On the basis of the characteristics of isostatic gravity anomalies, it is concluded that the Yellow Sea belongs to continental crustal isostatic area whose isostatic anomalies is smooth and slow. ReferencesHeiskanen, W. A., F. A. V. Meinesz, and S. A. Korff (1958), The Earth and Its Gravity Field, McGraw-Hill, New York. Meng, X. J., X. H. Zhang, and J. Y. Yang (2014), Geophysical survey in eastern China seas and the characteristics of gravity and magnetic fields, Marine Geoglogy

Restructuring of Turkey's electricity market and the share of hydropower energy: The case of the Eastern Black Sea Basin

International Nuclear Information System (INIS)

Uzlu, Ergun; Koemuercue, Murat ihsan; Akpinar, Adem

2011-01-01

This paper presents the historical development of Turkey's electricity power sector, the efforts for introducing competition in the power industry in Turkey, and the concerns regarding restructuring in Turkey. The contribution of the hydropower energy potential in Turkey to the reconstruction of the electricity structure in Turkey is also investigated. Then, among the 25 hydrological basins in Turkey, the Eastern Black Sea Basin located in the northeast of Turkey, which has great advantages from the view point of small hydropower potential or hydropower potential without storage, is chosen as the case study to carry out some investigations concerning its potential and to analyze the contribution of the private sector (the corporate body) in regard to the development of hydro potential in this basin within the scope of the 4628 Electricity Market Law. With this law, concerning the restructuring of the electricity market, private sector investments in this segment have increased. In total, 1524 hydroelectric power projects with 22 360 MW installed capacity has been implemented until January 22nd, 2009 and this figure is continuously rising. (author)

Effects of habitat and substrate complexity on shallow sublittoral fish assemblages in the Cyclades Archipelago, North-eastern Mediterranean Sea

Directory of Open Access Journals (Sweden)

S. GIAKOUMI

2013-02-01

Full Text Available This is the first study to explore fish community structure and its relations to habitat and topographic complexity in the shallow coastal waters of the Cyclades Archipelago, North-eastern Mediterranean Sea. In situ visual surveys were carried out at 233 sampling sites in 26 islands of the Cyclades Archipelago. Fish community parameters and biomass were estimated across seven substrate types: sand, seagrass, vertical walls, boulders, horizontal/subhorizontal continuous rock, rocky substrate with patches of sand, and rocky substrate with patches of sand and Posidonia oceanica. Topographic complexity and percentage of algal cover were estimated on hard substrate. Substrate type was found to be a determining factor affecting the structure and composition of fish assemblages. Species number, abundance and biomass were significantly lower in sandy areas and always higher on hard substrates, with seagrass habitats presenting intermediate values. Topographic complexity in rocky bottoms did not seem to affect species richness, density or biomass. This study provides a baseline for future evaluation of changes produced by potential management actions such as the creation of marine protected areas in the study region.

First record of Dichotomaria obtusata (Ellis & Solander Lamarck (Nemaliales, Rhodophyta in the Mediterranean Sea

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R. HOFFMAN

2015-03-01

Full Text Available Global climate change is causing the Mediterranean coastal area of Israel to gradually acquire tropical characteristics. Rising sea surface temperatures in the eastern Mediterranean basin have facilitated the introduction, settlement and establishment of hundreds of alien species (Zenetos et al. 2012. The vast majority of these exotic species are of Indo-Pacific origin. We report the occurrence of the genus Dichotomaria in the eastern Mediterranean on the basis of specimens identified as Dichotomaria cf. obtusata (J. Ellis & Solander Lamarck. Tetrasporophytes with sporangial initials were identified morphologically and confirmed molecularly using plastid rbcL sequences. We also discuss possible paths of introduction of this and other alien species into the Levantine Sea.

Metatranscriptomes reveal functional variation in diatom communities from the Antarctic Peninsula

KAUST Repository

Pearson, Gareth A

2015-04-14

Functional genomics of diatom-dominated communities fromthe Antarctic Peninsula was studied using comparative metatranscriptomics. Samples obtained from diatom-rich communities in the Bransfield Strait, the western Weddell Sea and sea ice in the Bellingshausen Sea/Wilkins Ice Shelf yielded more than 500K pyrosequencing reads that were combined to produce a global metatranscriptome assembly. Multi-gene phylogenies recovered three distinct communities, and diatom-assigned contigs further indicated little read-sharing between communities, validating an assembly-based annotation and analysis approach. Although functional analysis recovered a core of abundant shared annotations that were expressed across the three diatom communities, over 40% of annotations (but accounting for <10% of sequences) were community-specific. The two pelagic communities differed in their expression of N-metabolism and acquisition genes, which was almost absent in post-bloom conditions in the Weddell Sea community, while enrichment of transporters for ammonia and urea in Bransfield Strait diatoms suggests a physiological stance towards acquisition of reduced N-sources. The depletion of carbohydrate and energy metabolism pathways in sea ice relative to pelagic communities, together with increased light energy dissipation (via LHCSR proteins), photorespiration, and NO3 - uptake and utilization all pointed to irradiance stress and/or inorganic carbon limitation within sea ice. Ice-binding proteins and cold-shock transcription factors were also enriched in sea ice diatoms. Surprisingly, the abundance of gene transcripts for the translational machinery tracked decreasing environmental temperature across only a 4 °C range, possibly reflecting constraints on translational efficiency and protein production in cold environments. © 2015 International Society for Microbial Ecology All rights reserved.

Metatranscriptomes reveal functional variation in diatom communities from the Antarctic Peninsula

KAUST Repository

Pearson, Gareth A; Lago-Leston, Asuncion; Cá novas, Fernando; Cox, Cymon J; Verret, Frederic; Lasternas, Sebastian; Duarte, Carlos M.; Agusti, Susana; Serrã o, Ester A

2015-01-01

Functional genomics of diatom-dominated communities fromthe Antarctic Peninsula was studied using comparative metatranscriptomics. Samples obtained from diatom-rich communities in the Bransfield Strait, the western Weddell Sea and sea ice in the Bellingshausen Sea/Wilkins Ice Shelf yielded more than 500K pyrosequencing reads that were combined to produce a global metatranscriptome assembly. Multi-gene phylogenies recovered three distinct communities, and diatom-assigned contigs further indicated little read-sharing between communities, validating an assembly-based annotation and analysis approach. Although functional analysis recovered a core of abundant shared annotations that were expressed across the three diatom communities, over 40% of annotations (but accounting for <10% of sequences) were community-specific. The two pelagic communities differed in their expression of N-metabolism and acquisition genes, which was almost absent in post-bloom conditions in the Weddell Sea community, while enrichment of transporters for ammonia and urea in Bransfield Strait diatoms suggests a physiological stance towards acquisition of reduced N-sources. The depletion of carbohydrate and energy metabolism pathways in sea ice relative to pelagic communities, together with increased light energy dissipation (via LHCSR proteins), photorespiration, and NO3 - uptake and utilization all pointed to irradiance stress and/or inorganic carbon limitation within sea ice. Ice-binding proteins and cold-shock transcription factors were also enriched in sea ice diatoms. Surprisingly, the abundance of gene transcripts for the translational machinery tracked decreasing environmental temperature across only a 4 °C range, possibly reflecting constraints on translational efficiency and protein production in cold environments. © 2015 International Society for Microbial Ecology All rights reserved.

Terrestrial dissolved organic matter distribution in the North Sea.

Science.gov (United States)

Painter, Stuart C; Lapworth, Dan J; Woodward, E Malcolm S; Kroeger, Silke; Evans, Chris D; Mayor, Daniel J; Sanders, Richard J

2018-07-15

The flow of terrestrial carbon to rivers and inland waters is a major term in the global carbon cycle. The organic fraction of this flux may be buried, remineralized or ultimately stored in the deep ocean. The latter can only occur if terrestrial organic carbon can pass through the coastal and estuarine filter, a process of unknown efficiency. Here, data are presented on the spatial distribution of terrestrial fluorescent and chromophoric dissolved organic matter (FDOM and CDOM, respectively) throughout the North Sea, which receives organic matter from multiple distinct sources. We use FDOM and CDOM as proxies for terrestrial dissolved organic matter (tDOM) to test the hypothesis that tDOM is quantitatively transferred through the North Sea to the open North Atlantic Ocean. Excitation emission matrix fluorescence and parallel factor analysis (EEM-PARAFAC) revealed a single terrestrial humic-like class of compounds whose distribution was restricted to the coastal margins and, via an inverse salinity relationship, to major riverine inputs. Two distinct sources of fluorescent humic-like material were observed associated with the combined outflows of the Rhine, Weser and Elbe rivers in the south-eastern North Sea and the Baltic Sea outflow to the eastern central North Sea. The flux of tDOM from the North Sea to the Atlantic Ocean appears insignificant, although tDOM export may occur through Norwegian coastal waters unsampled in our study. Our analysis suggests that the bulk of tDOM exported from the Northwest European and Scandinavian landmasses is buried or remineralized internally, with potential losses to the atmosphere. This interpretation implies that the residence time in estuarine and coastal systems exerts an important control over the fate of tDOM and needs to be considered when evaluating the role of terrestrial carbon losses in the global carbon cycle. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

Denitrification as the dominant nitrogen loss process in the Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Ward, B.B.; Devol, A.H.; Rich, J.J.; Chang, B.X.; Bulow, S.E.; Naik, H.; Pratihary, A.K.; Jayakumar, A.

experiments in the Arabian Sea denitrification is responsible for 87-99% of the total N sub(2) production. The dominance of denitrification is reproducible using two independent isotope incubation methods. In contrast, anammox is dominant in the Eastern...

Challenging ICES age estimation protocols: lessons learned from the eastern Baltic cod stock

DEFF Research Database (Denmark)

Hüssy, Karin; Radtke, Krzysztof; Plikshs, Maris

2016-01-01

Over the recent decades, the International Council for the Exploration of the Sea (ICES) has set guidelines for best practise quality control of age estimation procedures. The applicability of these guidelines is assessed by reviewing the ageing issues of eastern Baltic cod (EBC) as a case study....

Geology of mud volcanos in the Eastern Mediterranean from combined sidescan and submersible surveys

NARCIS (Netherlands)

Zitter, T.A.C.; Huguen, C.; Woodside, J.M.

2005-01-01

Submersible observations and seafloor mapping over areas of mud volcanism in the eastern Mediterranean Sea reveal an abundance of methane-rich fluid emissions, as well as specific seep-associated fauna (e.g. tubeworms, bivalves and chemosynthetic bacteria) and diagenetic deposits (i.e. carbonates

Multiscale wind cycles and current pulses at the Black Sea eastern boundary

Science.gov (United States)

Melnikov, Vasiliy; Moskalenko, Lidija; Piotoukh, Vladimir; Zatsepin, Andrey

2015-04-01

The goal of the research is to examine meteorological descriptive elements, sea-water properties, regional hydrodynamics and energy conversion fluxes in order to study sea responses to the local and far-field weather system. The Black Sea is situated in the chain of internal basins between the North Atlantic and Central Asia deserts in the marginal interaction zone and, accordingly, is under the influence of the Azores and Siberian anticyclones, Arctic cold-air surges and subtropical desert belt to the south. The analysis is based on the data of modern oceanographic measuring network "Hydro-physical Polygon" of the Institute of oceanology, using contact and remote sensing methods, weather stations around the Black Sea coasts, including long-term (1938-2014) measurements at the Gelendzhik weather station. Various satellite and Reanalysis databases are used. Currently, there are three long-time measuring moored stations (each contains ADCP and thermistor chain) and scanning profiling system "Akvalog". Hydrological sections and field surveys using towed ADCP and CTD are performed on a regular basis. The data are accumulated in the coastal archive which allows calibration of satellite measurements and testing results of numerical modeling. Data processing includes data sets preparation, editing, time series statistical calculations using histograms, progressive vector diagrams, traditional Fourier spectral analysis including auto- and cross spectra, auto and mutual wavelet diagrams, moving spectrograms, vector data methods using rotary components, spectral invariants, empirical modes, hodograph and pre-specified spectrum representations on the basis of stochastic models with imposed dynamical assumptions. Due to the intermittent nature of the time rows, spectral representation is misleading, often. In order to identify the individual evolving dynamical phenomenon, typical background (seasonal) three-dimensional structures of the hydrological field, as well as

137Cs, 239+24Pu and 24Pu/239Pu atom ratios in the surface waters of the western North Pacific Ocean, eastern Indian Ocean and their adjacent seas

International Nuclear Information System (INIS)

Yamada, Masatoshi; Zheng Jian; Wang Zhongliang

2006-01-01

Surface seawater samples were collected along the track of the R/V Hakuho-Maru cruise (KH-96-5) from Tokyo to the Southern Ocean. The 137 Cs activities were determined for the surface waters in the western North Pacific Ocean, the Sulu and Indonesian Seas, the eastern Indian Ocean, the Bay of Bengal, the Andaman Sea, and the South China Sea. The 137 Cs activities showed a wide variation with values ranging from 1.1 Bq m -3 in the Antarctic Circumpolar Region of the Southern Ocean to 3 Bq m -3 in the western North Pacific Ocean and the South China Sea. The latitudinal distributions of 137 Cs activity were not reflective of that of the integrated deposition density of atmospheric global fallout. The removal rates of 137 Cs from the surface waters were roughly estimated from the two data sets of Miyake et al. [Miyake Y, Saruhashi K, Sugimura Y, Kanazawa T, Hirose K. Contents of 137 Cs, plutonium and americium isotopes in the Southern Ocean waters. Pap Meteorol Geophys 1988;39:95-113] and this study to be 0.016 yr -1 in the Sulu and Indonesian Seas, 0.033 yr -1 in the Bay of Bengal and Andaman Sea, and 0.029 yr -1 in the South China Sea. These values were much lower than that in the coastal surface water of the western Northwest Pacific Ocean. This was likely due to less horizontal and vertical mixing of water masses and less scavenging. 239+24 Pu activities and 24 Pu/ 239 Pu atom ratios were also determined for the surface waters in the western North Pacific Ocean, the Sulu and Indonesian Seas and the South China Sea. The 24 Pu / 239 Pu atom ratios ranged from 0.199 ± 0.026 to 0.248 ± 0.027 on average, and were significantly higher than the global stratospheric fallout ratio of 0.18. The contributions of the North Pacific Proving Grounds close-in fallout Pu were estimated to be 20% for the western North Pacific Ocean, 39% for the Sulu and Indonesian Seas and 42% for the South China Sea by using the two end-member mixing model. The higher 24 Pu / 239 Pu atom ratios

An overview of the ecological half-life of the 137Cs radioisotope and a determination of radioactivity levels in sediment samples after Chernobyl in the Eastern Black Sea, Turkey

Science.gov (United States)

Baltas, Hasan; Sirin, Murat; Dalgic, Goktug; Cevik, Ugur

2018-01-01

A study which determined the activity concentration of 137Cs in sediments contaminated by effluents from the Chernobyl accident which had collected along the coast of the Eastern Black Sea region in Turkey was carried out in 1993. Marine sediment samples were collected in 2015 from the same fifteen sampling points, and the activity concentrations of 226Ra, 232Th, 40K and 137Cs were determined for the sediment samples. The activity concentrations ranged from 10.94-25.95, 12.14-33.05, 265.74-459.89 and 2.08-37.45 Bq kg- 1 for 226Ra, 232Th, 40K and 137Cs respectively. The results showed that there was a steep decline in 137Cs within the sediment at most of the sampling sites from the Eastern Black Sea region during the 22-year period, except for two sites at which the measured levels were much higher. This may be the result of the combined effects of radioactive contaminant entry into this area from rivers, environmental changes and nuclear testing between 1993 and 2015. Furthermore, the ecological half-life (EHL) of the 137Cs radionuclide was estimated for the sediment samples, and radiological hazard parameters such as the absorbed dose rate in air (D), the annual effective dose equivalent (AEDE) and the excess lifetime cancer risk (ELCR) were calculated and compared with the international recommended values. It was shown that these sediments do not present any significant health risk for humans in this area.

The great triangular seismic region in eastern Asia: Thoughts on its dynamic context

Directory of Open Access Journals (Sweden)

Xianglin Gao

2011-01-01

Full Text Available A huge triangle-shaped tectonic region in eastern Asia plays host to numerous major earthquakes. The three boundaries of this region, which contains plateaus, mountains, and intermountain basins, are roughly the Himalayan arc, the Tianshan-Baikal, and longitude line ∼105°E. Within this triangular region, tectonism is intense and major deformation occurs both between crustal blocks and within most of them. Outside of this region, rigid blocks move as a whole with relatively few major earthquakes and relatively weak Cenozoic deformation. On a large tectonic scale, the presence of this broad region of intraplate deformation results from dynamic interactions between the Indian, Philippine Sea-West Pacific, and Eurasian plates, as well as the influence of deep-level mantle flow. The Indian subcontinent, which continues to move northwards at ∼40 mm/a since its collision with Eurasia, has plunged beneath Tibet, resulting in various movements and deformations along the Himalayan arc that diffuse over a long distance into the hinterland of Asia. The northward crustal escape of Asia from the Himalayan collisional zone turns eastwards and southeastwards along 95°–100°E longitude and defines the eastern Himalayan syntaxis. At the western Himalayan syntaxis, the Pamirs continue to move into central Asia, leading to crustal deformation and earthquakes that are largely accommodated by old EW or NW trending faults in the bordering areas between China, Mongolia, and Russia, and are restricted by the stable landmass northwest of the Tianshan-Altai-Baikal region. The subduction of the Philippine and Pacific plates under the Eurasian continent has generated a very long and narrow seismic zone along trenches and island arcs in the marginal seas while imposing only slight horizontal compression on the Asian continent that does not impede the eastward motion of eastern Asia. In the third dimension, there may be southeastward deep mantle flow beneath most of

Biosynthetic potential of actinomycetes in brown forest soil on the eastern coast of the aegean sea

Science.gov (United States)

Shirokikh, I. G.; Shirokikh, A. A.

2017-11-01

The taxonomic and functional structures of the actinomycetal complex in the litter and upper horizon of the brown forest soil was studied in a Pinus brutia var. pendulifolia forest on the eastern coast of the Aegean Sea. The complex of actinomycetes included representatives of the Streptomyces and Micromonospora genera and oligosporus forms. Streptomycetes predominated (73.8%) in the soil, and micromonospores (66.7%) were dominants in the litter. Thirty isolates of ten Streptomyces species from five series and three sections prevailed. In the upper soil horizon, species of the Helvolo-Flavus Helvolus section predominated (48%); the S. felleus species occurred most frequently. Among the isolated cultures, the S. globisporus and S. sindenensis species capable to produce antitumor antibiotics were found. The testing of the antimicrobial activity of the natural isolates showed that five strains inhibit the growth of pathogenic Fusarium sp., Alternaria sp., Acremonium sp., and Bipolaris sorokiniana fungi. When testing the effect of streptomycetes on the production of cellulases, a high-efficient strain belonging to the S. noboritoensis species was revealed. All the streptomycetes isolated from the brown forest soil produced auxins at the rate of 7.8 to 19.7 μg of indole acetic acid/mL of the liquid medium in the presence of 200 mg/L of tryptophan. Twelve isolates of streptomycetes were transferred to the collection of biotechnologically promising cultures for studying their properties.

Early to Middle Holocene sea level fluctuation, coastal progradation and the Neolithic occupation in the Yaojiang Valley of southern Hangzhou Bay, Eastern China

Science.gov (United States)

Liu, Yan; Sun, Qianli; Fan, Daidu; Dai, Bin; Ma, Fuwei; Xu, Lichen; Chen, Jing; Chen, Zhongyuan

2018-06-01

The Yaojiang Valley (YJV) of southern Hangzhou Bay was the birthplace of the well-known Hemudu Culture (HC), one of the representatives of Neolithic civilization in eastern China. To explore the magnitude of natural environmental effects on the HC trajectory, the palaeo-embayment setting of the YJV was studied in detail for the first time in terms of 3D Holocene strata supported by a series of new radiocarbon-dated cores. The results indicated that the local relative sea level rose rapidly during the Early Holocene in the YJV, reached its maximum flooding surface ca. 7900 cal yr BP, and then remained stable ca. 7900-7600 cal yr BP. Thereupon, an estuary stretching inland was first formed by marine transgression, and then, it was transformed to an alluvial-coastal plain by regressive progradation. The alluvial plain was initiated in the foothills and then spread towards the valley centre after sea level stabilization ca. 7600 cal yr BP. Accompanying these natural environmental changes, the earliest arrivals of foragers in the valley occurred no later than ca. 7000 cal yr BP. They engaged in rice farming and fostered the HC for approximately two millennia from ca. 7000-5000 cal yr BP as more lands developed from coastal progradation. The rise and development of the HC are closely associated with the sea level-induced landscape changes in the YJV in the Early-Middle Holocene, but the enigmatic exodus of the HC people after ca. 5000 cal yr BP is still contentious and possibly linked with the rapid waterlogging and deterioration of this setting in such a low-lying coastal plain as well as with associated social reasons.

Sea-to-air and diapycnal nitrous oxide fluxes in the eastern tropical North Atlantic Ocean

Directory of Open Access Journals (Sweden)

A. Kock

2012-03-01

Full Text Available Sea-to-air and diapycnal fluxes of nitrous oxide (N₂O into the mixed layer were determined during three cruises to the upwelling region off Mauritania. Sea-to-air fluxes as well as diapycnal fluxes were elevated close to the shelf break, but elevated sea-to-air fluxes reached further offshore as a result of the offshore transport of upwelled water masses. To calculate a mixed layer budget for N₂O we compared the regionally averaged sea-to-air and diapycnal fluxes and estimated the potential contribution of other processes, such as vertical advection and biological N₂O production in the mixed layer. Using common parameterizations for the gas transfer velocity, the comparison of the average sea-to-air and diapycnal N₂O fluxes indicated that the mean sea-to-air flux is about three to four times larger than the diapycnal flux. Neither vertical and horizontal advection nor biological production were found sufficient to close the mixed layer budget. Instead, the sea-to-air flux, calculated using a parameterization that takes into account the attenuating effect of surfactants on gas exchange, is in the same range as the diapycnal flux. From our observations we conclude that common parameterizations for the gas transfer velocity likely overestimate the air-sea gas exchange within highly productive upwelling zones.

Mud volcanoes and gas hydrates in the Anaximander mountains (Eastern Mediterranean Sea)

NARCIS (Netherlands)

Lykousis, V.; Alexandri, S.; Woodside, J.M.; de Lange, G.; Dahlmann, A.; Perissoratis, C.; Heeschen, K.; Ioakim, Chr.; Sakellariou, D.; Nomikou, P.; Rousakis, G.; Casas, D.; Ballas, D.; Ercilla, G.

2009-01-01

Detailed multibeam, sedimentological, and geophysical surveys provide ample new data to confirm that the Anaximander Mountains (Eastern Mediterranean) are an important area for active mud volcanism and gas hydrate formation. More than 3000 km of multibeam track length was acquired during two recent

Mechanisms of long-term mean sea level variability in the North Sea

Science.gov (United States)

Dangendorf, Sönke; Calafat, Francisco; Øie Nilsen, Jan Even; Richter, Kristin; Jensen, Jürgen

2015-04-01

We examine mean sea level (MSL) variations in the North Sea on timescales ranging from months to decades under the consideration of different forcing factors since the late 19th century. We use multiple linear regression models, which are validated for the second half of the 20th century against the output of a state-of-the-art tide+surge model (HAMSOM), to determine the barotropic response of the ocean to fluctuations in atmospheric forcing. We demonstrate that local atmospheric forcing mainly triggers MSL variability on timescales up to a few years, with the inverted barometric effect dominating the variability along the UK and Norwegian coastlines and wind (piling up the water along the coast) controlling the MSL variability in the south from Belgium up to Denmark. However, in addition to the large inter-annual sea level variability there is also a considerable fraction of decadal scale variability. We show that on decadal timescales MSL variability in the North Sea mainly reflects steric changes, which are mostly remotely forced. A spatial correlation analysis of altimetry observations and baroclinic ocean model outputs suggests evidence for a coherent signal extending from the Norwegian shelf down to the Canary Islands. This supports the theory of longshore wind forcing along the eastern boundary of the North Atlantic causing coastally trapped waves to propagate along the continental slope. With a combination of oceanographic and meteorological measurements we demonstrate that ~80% of the decadal sea level variability in the North Sea can be explained as response of the ocean to longshore wind forcing, including boundary wave propagation in the Northeast Atlantic. These findings have important implications for (i) detecting significant accelerations in North Sea MSL, (ii) the conceptual set up of regional ocean models in terms of resolution and boundary conditions, and (iii) the development of adequate and realistic regional climate change projections.

Distribution of aerobic anoxygenic phototrophs in the Eastern Adriatic Sea

Czech Academy of Sciences Publication Activity Database

Šantić, D.; Šestanović, S.; Vrdoljak, A.; Šolić, M.; Kušpilić, G.; Ninčević Gladan, Ž.; Koblížek, Michal

2017-01-01

Roč. 130, SEP 2017 (2017), s. 134-141 ISSN 0141-1136 R&D Projects: GA MŠk(CZ) LO1416 Institutional support: RVO:61388971 Keywords : Aerobic anoxygenic phototrophs * Adriatic sea * Picoplankton Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 3.101, year: 2016

Looking for evidence of climate change impacts in the eastern Irish Sea

Directory of Open Access Journals (Sweden)

L. S. Esteves

2011-06-01

Full Text Available Although storminess is often cited as a driver of long-term coastal erosion, a lack of suitable datasets has only allowed objective assessment of this claim in a handful of case studies. This reduces our ability to understand and predict how the coastline may respond to an increase in "storminess" as suggested by global and regional climate models. With focus on 16 km of the Sefton coastline bordering the eastern Irish Sea (UK, this paper analyses available measured datasets of water level, surge level, wave height, wind speed and barometric pressure with the objective of finding trends in metocean climate that are consistent with predictions. The paper then examines rates of change in shoreline position over the period 1894 to 2005 with the aim of establishing relationships with climatic variability using a range of measured and modelled metocean parameters (with time spans varying from two to eight decades. With the exception of the mean monthly wind speed, available metocean data do not indicate any statistically significant changes outside seasonal and decadal cycles. No clear relationship was found between changes in metocean conditions and rates of shoreline change along the Sefton coast. High interannual variability and the lack of long-term measurements make unambiguous correlations between climate change and shoreline evolution problematic. However, comparison between the North Atlantic Oscillation winter index (NAOw and coastline changes suggest increased erosion at times of decreasing NAOw values and reduced erosion at times of increasing NAOw values. Erosion tends to be more pronounced when decreasing NAOw values lead to a strong negative NAO phase. At present, anthropogenic changes in the local sediment budget and the short-term impact of extreme events are still the largest threat likely to affect coastal flooding and erosion risk in the short- and medium-term. Nevertheless, the potential impacts of climate change in the long

First record of the blackfin coral goby, Paragobiodon lacunicolus (Kendall and Goldsborough, 1911), from the Red Sea

KAUST Repository

Alpermann, Tilman J.

2013-09-13

Three specimens of the blackfin coral goby, Paragobiodon lacunicolus, were collected in 2010 and 2011 at different locations of the eastern Red Sea along the coast of Saudi Arabia. Reexamination of 14 museum specimens from Eritrea also confirmed the presence of the species for the western Red Sea. This represents the first published report of P. lacunicolus from the Red Sea. © 2013 Blackwell Verlag GmbH.

First record of the blackfin coral goby, Paragobiodon lacunicolus (Kendall and Goldsborough, 1911), from the Red Sea

KAUST Repository

Alpermann, Tilman J.; Mee, J. K L; Berumen, Michael L.

2013-01-01

Three specimens of the blackfin coral goby, Paragobiodon lacunicolus, were collected in 2010 and 2011 at different locations of the eastern Red Sea along the coast of Saudi Arabia. Reexamination of 14 museum specimens from Eritrea also confirmed the presence of the species for the western Red Sea. This represents the first published report of P. lacunicolus from the Red Sea. © 2013 Blackwell Verlag GmbH.

Paleogene magnetic isochrons and palaeo-propagators in the Arabian and Eastern Somali basins, NW Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Chaubey, A.K.; Dyment, J.; Bhattacharya, G.C.; Royer, J.-Y.; Srinivas, K.; Yatheesh, V.

A revised magnetic isochron map of the conjugate Arabian and Eastern Somali basins based on an up-to-date compilation of Indian, French, and other available sea-surface magnetic data are presented. The magnetic anomaly and the modulus...

Calculation of temperature distribution and rheological properties of the lithosphere along geotransect in the Red Sea region

Science.gov (United States)

Dérerová, Jana; Kohút, Igor; Radwan, Anwar H.; Bielik, Miroslav

2017-12-01

The temperature model of the lithosphere along profile passing through the Red Sea region has been derived using 2D integrated geophysical modelling method. Using the extrapolation of failure criteria, lithology and calculated temperature distribution, we have constructed the rheological model of the lithosphere in the area. We have calculated the strength distribution in the lithosphere and constructed the strength envelopes for both compressional and extensional regimes. The obtained results indicate that the strength steadily decreases from the Western desert through the Eastern desert towards the Red Sea where it reaches its minimum for both compressional and extensional regime. Maximum strength can be observed in the Western desert where the largest strength reaches values of about 250-300 MPa within the upper crust on the boundary between upper and lower crust. In the Eastern desert we observe slightly decreased strength with max values about 200-250 MPa within upper crust within 15 km with compression being dominant. These results suggest mostly rigid deformation in the region or Western and Eastern desert. In the Red Sea, the strength rapidly decreases to its minimum suggesting ductile processes as a result of higher temperatures.

Arabian Sea upwelling - A comparison between coastal and open ocean regions

Digital Repository Service at National Institute of Oceanography (India)

Muraleedharan, P.M.; PrasannaKumar, S.

The response of the eastern Arabian Sea to prevailing winds during an upwelling event, in the peak of southwest monsoon, was studied at both coastal and open ocean environment based on the data collected as a part of the Indian Joint Global Ocean...

The Sea Empress oil spill: cytochrome P450 levels, ethoxyresorufin O-deethylase activity and bile metabolites in migrating sea trout

International Nuclear Information System (INIS)

Bird, D.J.; Rotchell, J.M.; Newton, L.C.

1997-06-01

Following concern that migrating sea trout in the Afon Tywi and Eastern Cleddau in Wales may have been exposed to oil from the Sea Empress, either directly or via their food, biomarkers of oil pollution were investigated in 14 fish from these rivers and compared with 8 fish from that of a control on the River Dee in North Wales. Sea trout 'whitling' were collected by electrofishing from the tidal limits of each river in later August/early September, 1996. The mean total cytochrome P450 content in the livers were not significantly different between fish from the Tywi (341 pmol mg -1 protein), Cleddau (212 pmol mg -1 protein) or from those caught in the Dee (121 pmol mg -1 protein). The report concludes that some individual sea trout from the rivers Tywi and Cleddau may have been exposed to oil from the Sea Empress while feeding in estuarine waters. However, by the time they were captured in these rivers, compared to control fish caught in the Dee, differences between the mean P450 content, mean EROD activity and the bile metabolite profiles were not apparent. There was no evidence that the Sea Empress oil spill had serious detrimental effects on populations of migrating sea trout in Welsh rivers. (author)

Understanding the recent trend of haze pollution in eastern China: roles of climate change

Directory of Open Access Journals (Sweden)

H.-J. Wang

2016-04-01

Full Text Available In this paper, the variation and trend of haze pollution in eastern China for winter of 1960–2012 were analyzed. With the overall increasing number of winter haze days in this period, the 5 decades were divided into three sub-periods based on the changes of winter haze days (WHD in central North China (30–40° N and eastern South China (south of 30° N for east of 109° E mainland China. Results show that WHD kept gradually increasing during 1960–1979, remained stable overall during 1980–1999, and increased fast during 2000–2012. The author identified the major climate forcing factors besides total energy consumption. Among all the possible climate factors, variability of the autumn Arctic sea ice extent, local precipitation and surface wind during winter is most influential to the haze pollution change. The joint effect of fast increase of total energy consumption, rapid decline of Arctic sea ice extent and reduced precipitation and surface winds intensified the haze pollution in central North China after 2000. There is a similar conclusion for haze pollution in eastern South China after 2000, with the precipitation effect being smaller and spatially inconsistent.

Mesoscale variability of water masses in the Arabian Sea as revealed by ARGO floats

OpenAIRE

X. Carton; P. L'Hegaret

2011-01-01

By analysing ARGO float data over the last four years, some aspects of the mesoscale variability of water masses in the Arabian Sea are described.

The Red Sea Water outflow is strong in the Southwestern Gulf of Aden, in particular when a cyclonic gyre predominates in this region. Salinities of 36.5 and temperatures of 16 °C are found there between 600 and 1000 m depths. The Red Sea Water is more dilute in the eastern part of the Gulf, and fragments of this ...

Assessment of phenols and oil pollution in the eastern Levantine (Winter 1992)

International Nuclear Information System (INIS)

Noureddin, S.; Youssef, A.K.; Abousamra, F.; Youssef, H.

1999-01-01

Phenols and dissolved/dispersed petroleum hydrocarbons were determined to assess the level of organic pollution in the waters of the eastern Levantine sea (eastern Mediterranean) and Syrian shoreline. Sampling program was carried out in February 1992. The phenols concentrations were ranged between non detectable values and 0.88 μg/l. The dissolved/dispersed petroleum hydrocarbons concentrations were averaged from 1 to 37.5 μg/l in the studied seawater, 65.8% of petroleum hydrocarbons samples were ranged between 1 and 10 μg/l. The distribution of phenols and dissolved/dispersed petroleum hydrocarbons in seawater indicate to be governed by water circulation and external sources. (author)

Age, growth and utility of otolith morphometrics as a predictor of age in the wrasse Coris julis (Labridae from the eastern Adriatic Sea

Directory of Open Access Journals (Sweden)

Frane Škeljo

2012-09-01

Full Text Available Age and growth of Coris julis were determined by examining sagittal otoliths belonging to fish sampled between November 2008 and October 2009 in the eastern Adriatic Sea (north-central Mediterranean Sea. A total of 1102 specimens (528 males, 487 females and 87 individuals of indeterminate sex, ranging from 48 to 222 mm total length were analysed. Ninety-two per cent of the otoliths were readable and 68% of the specimens had two readings in agreement. Counting of daily rings revealed that the second opaque ring represents the first annulus (315.1±27.8 daily rings. The maximum observed age was 7 years for males and 5 years for females, with males dominating in higher age classes ( > 3 years and females in age classes 1+ and 2+. Growth was described by the von Bertalanffy growth curves and significant differences were found between males (L∞=29.10 cm, k=0.12 and t0=–1.48 and females (L∞=21.27 cm, k=0.21 and t0=–1.08. Otolith mass, length, width and thickness were determined for the otoliths belonging to 465 fish and the utility of these morphometrics as a predictor of age was evaluated. The most precise age estimations were obtained from the otolith length data, followed by the otolith mass.

Removing Regional Trends in Microgravity in Complex Environments: Testing on 3D Model and Field Investigations in the Eastern Dead Sea Coast (Jordan

Directory of Open Access Journals (Sweden)

A. Al-Zoubi

2013-01-01

Full Text Available Microgravity investigations are now recognized as a powerful tool for subsurface imaging and especially for the localization of underground karsts. However numerous natural (geological, technical, and environmental factors interfere with microgravity survey processing and interpretation. One of natural factors that causes the most disturbance in complex geological environments is the influence of regional trends. In the Dead Sea coastal areas the influence of regional trends can exceed residual gravity effects by some tenfold. Many widely applied methods are unable to remove regional trends with sufficient accuracy. We tested number of transformation methods (including computing gravity field derivatives, self-adjusting and adaptive filtering, Fourier series, wavelet, and other procedures on a 3D model (complicated by randomly distributed noise, and field investigations were carried out in Ghor Al-Haditha (the eastern side of the Dead Sea in Jordan. We show that the most effective methods for regional trend removal (at least for the theoretical and field cases here are the bilinear saddle and local polynomial regressions. Application of these methods made it possible to detect the anomalous gravity effect from buried targets in the theoretical model and to extract the local gravity anomaly at the Ghor Al-Haditha site. The local anomaly was utilized for 3D gravity modeling to construct a physical-geological model (PGM.

New records of five sponge species (Porifera) for the Black Sea.

Science.gov (United States)

Evcen, Alper; Çinar, Melih Ertan; Zengin, Mustafa; Süer, Serdar; Rüzgar, Melih

2016-04-13

The present study deals with five sponge species [Chalinula renieroides, Haliclona (Halichoclona) fulva, H. (Rhizoniera) rosea, Hymedesmia (Hymedesmia) pansa and Ircinia variabilis] belonging to 3 families (Chalinidae, Hymedesmiidae, and Irciniidae) found at one locality (near the opening of Kızılırmak River) on the Black Sea coast of Turkey. All these species are new records for the Black Sea. Three species (Chalinula renieroides, H. (R.) rosea and H. (H.) pansa] are also new records for the marine fauna of Turkey. All these species were previously reported from Mediterranean Sea and the eastern Atlantic Ocean. The morphological and distributional features of these species are presented.

PLASTIC POLLUTION ON RIZE SARAYKOY BEACH IN THE SOUTHEASTERN BLACK SEA

OpenAIRE

Esensoy Şahin, Fatma Başak; Karacan, Furkan; Aytan, Ülgen

2018-01-01

Marine litter is an important environmental problem in the Black Seawhich is a semi-enclosed with high river discharge. Plastics are the mostcommon marine litter in the Black Sea as it’s in the other regions in theworld. Plastic litter were monitored in the Saraykoy beach of Rize in theSouth-Eastern Black Sea between June 2016 and March 2017. The beach littercollected seasonally following OSPAR beach monitoring methodology and collectedin 100 m beach section and separated into types. During t...

FEATURES AND PROBLEMS WITH HISTORICAL GREAT EARTHQUAKES AND TSUNAMIS IN THE MEDITERRANEAN SEA

Directory of Open Access Journals (Sweden)

Lobkovsky L.

2016-11-01

Full Text Available The present study examines the historical earthquakes and tsunamis of 21 July 365 and of 9 February 1948 in the Eastern Mediterranean Sea. Numerical simulations were performed for the tsunamis generated by underwater seismic sources in frames of the keyboard model, as well as for their propagation in the Mediterranean Sea basin. Similarly examined were three different types of seismic sources at the same localization near the Island of Crete for the earthquake of 21 July 365, and of two different types of seismic sources for the earthquake of 9 February 1948 near the Island of Karpathos. For each scenario, the tsunami wave field characteristics from the earthquake source to coastal zones in Mediterranean Sea’s basin were obtained and histograms were constructed showing the distribution of maximum tsunami wave heights, along a 5-m isobath. Comparison of tsunami wave characteristics for all the above mentioned scenarios, demonstrates that underwater earthquakes with magnitude M > 7 in the Eastern Mediterranean Sea basin, can generate waves with coastal runup up to 9 m.