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

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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 levels of radionuclides and heavy metals in Black Sea ecosystems (Bulgaria)

International Nuclear Information System (INIS)

Strezov, A.; Nonova, Tz.

2006-01-01

In order to evaluate the influence of geographically varying marine ecosystem properties on the uptake of radionuclides and toxic metals in marine environment, samples of sand, slime and silt sediments were taken during the period 1991-2004. Samples were collected from different zones along the Bulgarian Black Sea coast - from the north Romanian border (Durankulak) to the South Turkish border (Rezovo). Technogenic and natural radionuclides were measured by Low-level Gamma Spectroscopy using HPGe detector with 35 % counting efficiency and energy resolution 1.8 KeV (1332 KeV). Heavy metals (HM) were measured by Atomic Absorption Spectrometry (AAS) - ETAAS (Perkin - Elmer Zeeman 3030 with graphite furnace) and flame AAS - Pye Unicam SP 1950. The measured radionuclides concentrations in Black Sea sediments were found to depend on sediment type - slime sediments accumulate technogenic ( 1 37Cs) and natural nuclides (U and Th series) to the highest extent. Considerably low levels of technogenic and natural radionuclides and a narrow concentration intervals were established for sand and silt sediment samples. The intercomparison of radionuclide and HM content in bottom sediments from one and the same sampling location gives information for mechanisms of radionuclide transfer and shows the trend of potential hazard of anthropogenic impact on marine ecosystems. The obtained data show that highest nuclide and heavy metal content in Black Sea sediments were determined in the northern part of the Black Sea coast. It can be attributed to the influence of the big rivers entering the northern part of the Black Sea - Danube, Dnyepr, Dnester. Data for radionuclides and heavy metals in sediments are in the limits of the cited in literature natural levels, showing no additional anthropogenic contamination

90Sr content in the Black Sea bottom sediments after the Chernobyl NPP accident and its use as a radiotracer for an assessment of bottom settlement rate

International Nuclear Information System (INIS)

Mirzoyeva, N. Y.; Egorov, V. N.; Polikarpov, G. G.

2006-01-01

The increase of 9 0Sr concentrations in the Black Sea bottom sediments along to western coast of the Black Sea and south part of Crimea was observed in 1987-1988 years. To our opinion, it was connected with hydrological processes (for example, currents), occurring in the given sea parts. The most polluted by post-Chernobyl 9 0Sr areas were bottom sediments of Dnieper, Dniester and Danube River deltas, territory of an arrangement of a main channel of the North-Crimea Channel - region of a peninsula Tarkhankut, southeast part of Crimea (Feodosiya area). The similar situation in confined of the greatest contents 9 0Sr to the specified areas not only is kept with time (till 2000), but the process of increase of 9 0Sr concentration in bottom sediments of the investigated regions is observed. So average concentration of 9 0Sr in Dnieper River delta bottom sediments in 1987 was 28,5 Bq kg - 1 , in 2000 - 148,2 28,5 Bq kg - 1 of Dry Weight. Such character of 9 0Sr redistribution shows, that both in first years after Chernobyl NPP accident, and in the following time, the entry of 9 0Sr in the Black Sea basin occurs, basically, with water flow of the large rivers in a northwest part of the Black Sea, discharge waters of the North-Crimean Channel. These sources of 9 0Sr input to the Black Sea ecosystem considerably prevailed above direct atmospheric pollution by given radionuclide in April-May 1986 at once after the Chernobyl NPP accident. On the base of monitoring researches results the maps of 9 0Sr dynamics redistribution in the Black Sea bottom sediments (0-5 cm) since 1986 (Chernobyl NPP accident) up to 2000 were sketched out. The distribution of 9 0Sr radionuclide in the bottom sediments columns, which were selected from the Corukh river mouth region and from the Dnieper-Bug estuary area, is investigated. The peaks of 9 0Sr increased contents were founded in the profile of its vertical distribution in the bottom sediments. These peaks correspond to the periods of 9 0Sr

On The Black Sea Surozhian

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Caraivan, Glicherie; Corneliu, Cerchia

2016-04-01

Some Black Sea researchers still support the idea of no other connection to the Mediterranean Sea between LGM and Karangatian Stage (Riss - Wurm). We try to clarify the source of these disagreements. C14 AMS age data (HERAS Project) made on undisturbed samples from a new Mamaia drilling hole where compared with the classical Black Sea stratigraphic schemes. A first transgressive event (Zone D) is found between 38.00 - 20.20 m depth. Zone D4 shows a fairly rapid rise of sea level, about 10 m below the present one indicating an inner shelf marine polyhaline environment. AMS age data show 14C ages between 53690 - 47359 y (MIS 1), corresponding to the "Surozhian Beds" of Popov. The "beach rock" from Zone E marks the decrease of the sea level after the maximum reached in Zone D4. Zone E mollusc shells AMS data, indicate 14C ages of 48724 - 44604 y, suggesting a long-time reworked material from the previous D4 zone sediments, and represents the beginning of the "regressive Tarkankutian" sequence.The Last Glacial Maximum (LGM) led to the retreat of the sea level down to about 100 m below the current one (27-17 ky BP), followed by an retreat of the shoreline to the present position. At the beginning of the Holocene - MIS 1 (8408-8132 cal. y BP), Black Sea brackish water level grew rapidly, up to -14 m below the present one (Zone F: 22, 57-20, 20 m). Zone F deposits could be correlated with the Bugazian strata. Then, a continuous rising of the Black Sea level is recorded up to a maximum of -2 m under the present one, about 6789 - 7063 cal. y BP, when a transgressive spurt ("Neolithic transgression") may have taken place. After that, given a weak Danubian sedimentary input, coastal erosion intensified. The coarse sandy sediments were reworked and pushed over the previous peat deposits, and suggest a classical "sedimentary regression", not a sea-level decrease. During the last 1.5 ky, sea level has risen towards the current one. Previous C14 dates from "Karangatian

Quantification of Microbial Communities in Subsurface Marine Sediments of the Black Sea and off Namibia.

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Schippers, Axel; Kock, Dagmar; Höft, Carmen; Köweker, Gerrit; Siegert, Michael

2012-01-01

Organic-rich subsurface marine sediments were taken by gravity coring up to a depth of 10 m below seafloor at six stations from the anoxic Black Sea and the Benguela upwelling system off Namibia during the research cruises Meteor 72-5 and 76-1, respectively. The quantitative microbial community composition at various sediment depths was analyzed using total cell counting, catalyzed reporter deposition - fluorescence in situ hybridization (CARD-FISH) and quantitative real-time PCR (Q-PCR). Total cell counts decreased with depths from 10(9) to 10(10) cells/mL at the sediment surface to 10(7)-10(9) cells/mL below one meter depth. Based on CARD-FISH and Q-PCR analyses overall similar proportions of Bacteria and Archaea were found. The down-core distribution of prokaryotic and eukaryotic small subunit ribosomal RNA genes (16S and 18S rRNA) as well as functional genes involved in different biogeochemical processes was quantified using Q-PCR. Crenarchaeota and the bacterial candidate division JS-1 as well as the classes Anaerolineae and Caldilineae of the phylum Chloroflexi were highly abundant. Less abundant but detectable in most of the samples were Eukarya as well as the metal and sulfate-reducing Geobacteraceae (only in the Benguela upwelling influenced sediments). The functional genes cbbL, encoding for the large subunit of RuBisCO, the genes dsrA and aprA, indicative of sulfate-reducers as well as the mcrA gene of methanogens were detected in the Benguela upwelling and Black Sea sediments. Overall, the high organic carbon content of the sediments goes along with high cell counts and high gene copy numbers, as well as an equal abundance of Bacteria and Archaea.

Nannoplankton and uranium concentration relations in the Black Sea Deposits

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Vedia TOKER

1983-12-01

Full Text Available Nannoplanktons obtained from sixty-two core samples taken from twenty-three holes penetrated in the Southern part of Black Sea were investigated in this work. Twelve species belonging to the Emiliania huxleyi zone (NN 21-Holocene were determined. Emiliania huxleyi (Lohmann came into existence in Black Sea three thousand years ago and is very abundant in these sediments. This study clearly showed that uranium concentration increases with increasing nannoplankton content of the sediments. It is also observed that the uranium oxide (U3O8 contents of the Emiliania huxleyi (Lohmann accumulations on the abyssal plains are higher than those other sediments in the same environments.

Instrumental neutron activation analysis of the spatial distribution of uranium, thorium and rare earth elements of surficial sediments from Black sea coast nearby Istanbul

International Nuclear Information System (INIS)

Akyuz, T; Bolcal, C.; Akyuz, S.; Mukhamedshina, N.M.; Mirsagatova, A.A

2006-01-01

Full text: The Black Sea is an inland sea between south-eastern Europe and Asia minor. It is the largest anoxic marine basin in the word and connected to the Mediterranean Sea by the Bosporus and the Sea of Marmara, to the Sea of Azov by the Strait of Kerch. One of the most useful approaches to long-term monitoring of aquatic systems is the analysis of marine sediments. In this study the abundance of uranium, thorium and some rare earth elements was analysed in surface sediments of the Southern part of the Black Sea using instrumental neutron activation analysis. The spatial distribution patterns of the elements studied were investigated. The surficial sediment samples (0-4 cm) were collected during 1999-2005, from 18 sampling stations of the Turkish Coast of the Black Sea, by using a Lenz Bottom Sampler and were deposited into plastic bags. The samples were dried at 40 degrees Celcius for 24 hours, crushed and homogenised prior to the analysis and were irradiated simultaneously with reference materials at a fission spectra neutron flux of the density of 5.10 1 3 cm - 2.s - 1 (WWR-SM) nuclear reactor of Institute of Nuclear Physics, Tashkent, Uzbekistan. The gamma-spectra were measured in a gamma-spectrometer. A linear regression correlation test was performed to investigate the correlation between the elemental concentrations of our sediment samples. Correlation analysis revealed close relationships between Th and U (r=0.82), Th and La (r=0.87), Th and Ce (r=0.89). In nature, rare earth elements are often associated to thorium, thus the results indicate that Th and Lanthanides have a natural origin. The mean values of thorium (8.38) to uranium (3.80) is found to be Th/U= 2.20

Natural occurring radionuclide 210Po in the components of the Black Sea ecosystem

International Nuclear Information System (INIS)

Lazorenko, G. G.; Polikarpov, G. G.

2006-01-01

The interest to study of the behavior of naturally occurring radionuclide 2 10Po in marine ecosystem was caused by its main contribution to the doses of irradiation to hydrobionts. This work presents own data of 2 10Po concentrations determined in water, bottom sediments and hydrobionts of the Black Sea in 1998-2004. 2 10Po concentrations in water varied from 0.58 to 1.02 Bqxm - 3. Their range in bottom sediments from shelf zone and open part of the Black Sea was 11.5-496.5 Bqxkg - 1 dry weight with maximum in the North-West region. The range of 2 10Po concentrations in bottom sediments from the Eastern part of the Black Sea was 4.5-220 Bqxkg-1 dry weight. Concentration factors (CF) of 2 10Po in bottom sediments reached 10 4 -10 5 . 2 10Po concentrations in the Black Sea hydrobionts are reported and compared with published data in the same taxa. The range of 2 10Po concentrations in the Black Sea mesozooplankton was 1.7-3.5 Bqxkg - 1 wet weight. It was 1.9-2.9 Bqxkg - 1 wet weight in the representative species of macro plankton community, namely the ctenophore Beroe ovata. 2 10Po concentrations in the Black Sea fishes depend on their belonging to different ecological groups and decrease from pelagic species to demersal and bottom ones. 2 10Po concentrations in the Black Sea mollusks excluding small species Nana nerithea were on the highest levels determined in hydrobionts inhabiting in this region. Concentration factors of this radionuclide, estimated on a wet weight basis, reached values of 1.5x10 3 for macrophytes, 4x10 3 for total zooplankton, 10 3 -10 4 for the entire fishes, depending on their ecological groups affiliation and (3.0-6.7) x10 4 for mollusks. So, the ability of the Black Sea hydrobionts to accumulate natural radionuclide 2 10Po is comparable with that of similar species from others marine and oceanic areas

Study of radioactivity among te Bulgarian Black Sea coastal zone - results from the NIMH monitoring program

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Veleva, B.; Kolarova, M.; Mungov, G. [National Institute of Meteorology and Hydrology, Bulgarian Academy of Sciences, Sofia (Bulgaria)

2011-07-01

In the frame of the NIMH at BAS investigations of the Black sea radioactivity were initiated in 1978 with a development of a monitoring campaign. Samples of sea waters, sediments and algae were collected from several sampling sites along the coastal zone and measured by gamma-spectrometry. Results on gamma-emitting radio-nuclide's measurements in the Black sea coastal waters were published in the 80's. After the Chernobyl accident during the period between 1986-1989 seasonal-fields sampling campaigns were organised and radioactivity of algae and bottom sediments was estimated. Harmonized sampling strategies, analytical procedures and related data information exchange for radioactivity of seawater, sediment and biota in coastal areas of Black Sea countries were developed under the IAEA TCP Black Sea Project. The present work reports results of the monitoring programme of the NIMH of Bulgaria developed in the frame of the IAEA projects for the Black Sea basin. From 1993 to 2005 regular seasonal sampling was performed in 5 sampling sites along the Bulgarian Black Sea shore. Results of the dissolved '1'3'7Cs concentrations in sea water, sand, algae, and fish samples are discussed. The data for the different radio-isotopes measured in algae, fish and sea sediment samples are given in comparison with other investigations. A complex assessment of Cs-137 concentrations as important tracer and indicator of the marine processes is made on a long-term basis. (author)

Study of radioactivity among te Bulgarian Black Sea coastal zone - results from the NIMH monitoring program

International Nuclear Information System (INIS)

Veleva, B.; Kolarova, M.; Mungov, G.

2011-01-01

In the frame of the NIMH at BAS investigations of the Black sea radioactivity were initiated in 1978 with a development of a monitoring campaign. Samples of sea waters, sediments and algae were collected from several sampling sites along the coastal zone and measured by gamma-spectrometry. Results on gamma-emitting radio-nuclide's measurements in the Black sea coastal waters were published in the 80's. After the Chernobyl accident during the period between 1986-1989 seasonal-fields sampling campaigns were organised and radioactivity of algae and bottom sediments was estimated. Harmonized sampling strategies, analytical procedures and related data information exchange for radioactivity of seawater, sediment and biota in coastal areas of Black Sea countries were developed under the IAEA TCP Black Sea Project. The present work reports results of the monitoring programme of the NIMH of Bulgaria developed in the frame of the IAEA projects for the Black Sea basin. From 1993 to 2005 regular seasonal sampling was performed in 5 sampling sites along the Bulgarian Black Sea shore. Results of the dissolved '1'3'7Cs concentrations in sea water, sand, algae, and fish samples are discussed. The data for the different radio-isotopes measured in algae, fish and sea sediment samples are given in comparison with other investigations. A complex assessment of Cs-137 concentrations as important tracer and indicator of the marine processes is made on a long-term basis. (author)

Study of seasonal dynamics of sedimentation evacuation of suspended matter, nutrients and pollutants from the surface water layer of the Black Sea during 1992-1994

International Nuclear Information System (INIS)

Gulin, S.B.; Polikarpov, G.G.; Egorov, V.N.; Krivenko, O.V.; Stokozov, N.A.; Zherko, N.V.

1995-01-01

A series of regular measurements of sedimentation evacuation of suspended matter, nutrients (carbon, nitrogen) and pollutants (mercury, polychlorided biphenyls) from the surface water layer was carried out with 1-2 month interval between the measurements using 234 Th in the region of western cyclonic circulation of the Black Sea. It allowed to estimate the seasonal dynamics and to obtain average annual values of dientrophication and sedimentational self-purification of the euphotic zone of the Western part of the Black Sea. The parallel measurements of the rates of sedimentation evacuation of suspended organic nitrogen from the euphotic zone, which were performed using 234 Th and determining the so called products of phitoplankton by the absorption of 15 N traced nitrates and ammonium, give practically identical results. 19 refs.; 5 figs

River delta shoreline reworking and erosion in the Mediterranean and Black Seas: the potential roles of fluvial sediment starvation and other factors

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Manon Besset

2017-09-01

Full Text Available The Mediterranean basin (including the Black Sea is characterized by a plethora of deltas that have developed in a wave-influenced setting. Many of these deltas are sourced in sediments by river catchments that have been variably dammed. The vulnerability status of a selection of ten deltas subject to different levels of reduction in fluvial sediment supply following damming was analysed by quantifying changes in delta protrusion area and protrusion angle over the last 30 years. The rationale for choosing these two metrics, which do not require tricky calculations of longshore bedload transport volumes and river ‘influence’, is that as sediment supply wanes, increasing relative efficiency of waves leads to longshore redistribution of reworked sediments and progressive ‘flattening’ of the delta protrusion. The results show that eight of the ten deltas (Nile, Rhône, Ebro, Ceyhan, Arno, Ombrone, Moulouya, Medjerda are in erosion, whereas two (Danube, Po show stability, but the statistical relationship between change in delta protrusion area and sediment flux reduction is poor, thus suggesting that the role of dams in causing delta shoreline erosion may have been over-estimated. But this poor relationship could also be due to a long temporal lag between dam construction and bedload removal and transport to the coast downstream of dams, and, where the delta protrusion is being eroded, to bedload trapping by shoreline engineering structures and by elongating delta-flank spits. Other potential influential factors in shoreline change include subsidence, sea-level rise, storminess, exceptional river floods, and managed sediment releases downstream of dams. A longer observation period and high-resolution sediment-budget studies will be necessary to determine more definitively to which extent continued trapping of sediment behind dams will impact overall delta stability in the Mediterranean and Black Seas. Mitigation of delta erosion is likely to

Hydrologic Control on Bacterial Nitrogen Fixation in the Holocene Black Sea

Science.gov (United States)

Fulton, J. M.; Arthur, M. A.; Freeman, K. H.

2008-12-01

Stratified oceans of the Phanerozoic Oceanic Anoxic Events apparently were dominated by bacterial nitrogen fixation. Decreased marine N:P nutrient ratios resulting from increased denitrification and decreased phosphate burial efficiency under anoxic waters drove this nutrient regime. This model is upheld by the presence of cyanobacterial hopanoid biomarkers in sedimentary records and δ15N values indicative of nitrogen fixation. However, in the largest modern redox-stratified marine basin, the Black Sea, bacterial nitrogen fixation seems to be only a minor contributor to the nitrogen cycle. In this study, we use geochemical proxies to evaluate the role of bacterial nitrogen fixation during the deposition of the Holocene Black Sea sapropel, starting 7.8 ka. We report compound-specific nitrogen and carbon stable isotope values of pyropheophytin a, a chlorophyll degradation product, and bacteriochlorophyll e produced by green sulfur bacteria. We also present the surprising finding of scytonemin, a pigment produced only by filamentous cyanobacteria exposed to ultraviolet radiation, in certain intervals in these sediments. In the Holocene, nitrogen fixation in the Black Sea is most prominent during times of reduced river water influx. This directly decreases the external flux of nitrate into the surface waters. Reduced freshwater influx also decreases the volume of low salinity water dispersed around the sea by the Rim Current, allowing the chemocline to shoal along the margins. Previous geochemical studies have described this changing chemocline geometry. The exposure of shallow water sediments to anoxic waters further stimulates nitrogen fixation by releasing more phosphorus to the system. Nitrogen fixation is recorded in the sediments as bulk and compound-specific pyropheophytin a δ15N values near 0 ‰ and -5 ‰, respectively. We have also detected scytonemin in two intervals characterized by especially low δ15N values. This compound suggests abundant filamentous

Secondary radioactive contamination of the Black Sea after Chernobyl accident: recent levels, pathways and trends

International Nuclear Information System (INIS)

Gulin, S.B.; Mirzoyeva, N.Yu.; Egorov, V.N.; Polikarpov, G.G.; Sidorov, I.G.; Proskurnin, V.Yu.

2013-01-01

The recent radionuclide measurements have showed that concentrations of the Chernobyl-derived 137 Cs and 90 Sr in the surface Black Sea waters are still relatively high, reaching 56 and 32 Bq m −3 , respectively. This is comparable or even exceeds the pre-Chernobyl levels (∼16 Bq 137 Cs and 22 Bq 90 Sr per m 3 as the basin-wide average values). The measurements have revealed that the Black Sea continues to receive Chernobyl radionuclides, particularly 90 Sr, by the runoff from the Dnieper River. An additional source of 90 Sr and 137 Cs was found in the area adjacent to the Kerch Strait that connects the Black Sea and the Sea of Azov. This may be caused by the inflow of the contaminated Dnieper waters, which come to this area through the North-Crimean Canal. The long-term monitoring of 137 Cs and 90 Sr concentration in the Black Sea surface waters and in the benthic brown seaweed Cystoseira sp., in comparison with the earlier published sediment records of the radionuclides, have showed signs of a secondary radioactive contamination, which has started to increase since the late 1990's. This may be the result of the combined effect of a higher input of radionuclides from the rivers in 1995–1999 due to an increased runoff; and a slow transport of the particulate bound radionuclides from the watersheds followed by their desorption in seawater from the riverine suspended matter and remobilization from the sediments adjacent to the river mouths. -- Highlights: • Concentration of 137 Cs and 90 Sr in the Black Sea water is still relatively high. • The Black Sea continues to receive considerable radionuclide amount from the rivers. • The North-Crimean Canal is significant source of the Black Sea radioactivity. • Secondary radioactive contamination of the Black Sea increased in the late 1990's. • Radionuclide remobilization from sediments leads to a further Black Sea pollution

7000 years of Emiliania huxleyi viruses in the Black Sea.

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Coolen, Marco J L

2011-07-22

A 7000-year record of Coccolithovirus and its host, the calcifying haptophyte Emiliania huxleyi, was reconstructed on the basis of genetic signatures preserved in sediments underlying the Black Sea. The data show that the same virus and host populations can persist for centuries. Major changes in virus and host populations occurred during early sapropel deposition, ~5600 years ago, and throughout the formation of the coccolith-bearing sediments of Unit I during the past 2500 years, when the Black Sea experienced dramatic changes in hydrologic and nutrient regimes. Unit I saw a reoccurrence of the same host genotype thousands of years later in the presence of a different subset of viruses. Historical plankton virus populations can thus be included in paleoecological and paleoenvironmental studies.

Diversity and abundance of sulfate-reducing microorganisms in the sulfate and methane zones of a marine sediment, Black Sea RID A-8182-2008

DEFF Research Database (Denmark)

Leloup, Julie; Loy, Alexander; Knab, Nina J.

2007-01-01

branching sequences which might represent Gram-positive spore-forming sulfate- and/or sulfite-reducing microorganisms. We thus hypothesize that terminal carbon mineralization in surface sediments of the Black Sea is largely due to the sulfate reduction activity of previously hidden SRM. Although these novel...

Century-scale high-resolution black carbon records in sediment cores from the South Yellow Sea, China

Science.gov (United States)

Xu, Xiaoming; Hong, Yuehui; Zhou, Qianzhi; Liu, Jinzhong; Yuan, Lirong; Wang, Jianghai

2018-01-01

Black carbon (BC) has received increasing attention in the last 20 years because it is not only an absorbent of toxic pollutants but also a greenhouse substance, preserving fire-history records, and more importantly, acting as an indicator of biogeochemical cycles and global changes. By adopting an improved chemothermal oxidation method (WXY), this study reconstructed the century-scale high-resolution records of BC deposition from two fine-grained sediment cores collected from the Yellow Sea Cold Water Mass in the South Yellow Sea. The BC records were divided into five stages, which exhibited specific sequences with three BC peaks at approximately 1891, 1921, and 2007 AD, representing times at which the first heavy storms appeared just after the termination of long-term droughts. The significant correlation between the times of the BC peaks in the cores and heavy storms in the area of the Huanghe (Yellow) River demonstrated that BC peaks could result from markedly strengthened sedimentation due to surface runoff, which augmented the atmospheric deposition. Stable carbon isotope analysis indicated that the evident increase in carbon isotope ratios of BC in Stage 5 might have resulted from the input of weathered rock-derived graphitic carbon cardinally induced by the annual anthropogenic modulation of water-borne sediment in the Huanghe River since 2005 AD. Numerical calculations demonstrated that the input fraction of graphitic carbon was 22.97% for Stage 5, whereas no graphitic carbon entered during Stages 1 and 3. The obtained data provide new and important understanding of the source-sink history of BC in the Yellow Sea.

Geochemical characteristics of Holocene laminated sapropel (unit II) and underlying lacustrine unit III in the Black Sea

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Dean, Walter E.; Arthur, Michael A.

2011-01-01

eg 1 of the 1988 R/V Knorr expeditions to the Black Sea recovered 90 gravity and box cores. The longest recovery by gravity cores was about 3 meters, with an average of about 2.5 meters, recovering all of the Holocene and upper Pleistocene sections in the Black Sea. During the latest Pleistocene glaciation, sea level dropped below the 35-meters-deep Bosporus outlet sill of the Black Sea. Therefore throughout most of its history the Black Sea was a lake, and most of its sediments are lacustrine. The oldest sediments recovered (older than 8,000 calendar years) consist of massive to coarsely banded lacustrine calcareous clay designated as lithologic Unit III, generally containing less than 1 percent organic carbon (OC). The base of overlying Unit II marks the first incursion of Mediterranean seawater into the Black Sea, and the onset of bottom-water anoxia about 7,900 calendar years. Unit II contains as much as 15 percent OC in cores from the deepest part of the Black Sea (2,200 meters). The calcium carbonate (CaCO3) remains of the coccolith Emiliania huxleyi form the distinctive white laminae of overlying Unit I. The composition of Unit III and Unit II sediments are quite different, reflecting different terrigenous clastic sources and increased contributions from hydrogenous and biogenic components in anoxic Unit II sapropel. In Unit II, positive covariance between OC and three trace elements commonly concentrated in OC-rich sediments where sulfate reduction has occurred (molybdenum, nickel, and vanadium) and a nutrient (phosphorus) suggest a large marine source for these elements although nickel and vanadium also have a large terrigenous clastic source. The marine sources may be biogenic or hydrogenous. A large biogenic source is also suggested for copper and cobalt. Because abundant pyrite forms in the water column and sediments of the Black Sea, we expected to find a large hydrogenous iron component, but a strong covariance of iron with aluminum suggests that the

Radioecological monitoring of the Black Sea basin following the Chernobyl NPP accident

International Nuclear Information System (INIS)

Kulebakina, L.G.; Polikarpov, G.G.

1991-01-01

A monitoring programme was drawn up to study the radioecological situation of the Black Sea basin following the Chernobyl NPP accident, with studies being carried out from May 1986 onwards to determine the levels of radioactive contamination in various parts of the Black Sea, the Sea of Azov and the Aegean Sea, including the estuaries of major rivers (Dnieper, Danube, Dniester and Don) and shelf areas of the Black Sea and the Sea of Azov. The work focused on long-lived radionuclides ( 90 Sr and 137 Cs), with the migration dynamics of these radionuclides in the aquatic environment, bed sediments and aquatic biota (including plants, molluscs, crustacea and fish) being studied. We compared the behaviour of radionuclides in the aquatic environment of the Dnieper reservoirs following the Chernobyl accident (our data) with the behaviour of radionuclides in lakes in the Urals following the Kyshtym accident (published data). As in the case of the lakes in the Urals, the Dnieper waters contain substantial concentrations of 90 Sr as a result of the Chernobyl accident, and 90 Sr therefore enters the Black Sea with the Dnieper waters. The paper compares the contribution of the Chernobyl accident to radioactive contamination of the Black Sea with that of global fallout. (author)

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

Isoprenoid quinones resolve the stratification of microbial redox processes in a biogeochemical continuum from the photic zone to deep anoxic sediments of the Black Sea.

Science.gov (United States)

Becker, Kevin W; Elling, Felix J; Schröder, Jan M; Lipp, Julius S; Goldhammer, Tobias; Zabel, Matthias; Elvert, Marcus; Overmann, Jörg; Hinrichs, Kai-Uwe

2018-03-09

The stratified water column of the Black Sea serves as a model ecosystem for studying the interactions of microorganisms with major biogeochemical cycles. Here we provide detailed analysis of isoprenoid quinones to study microbial redox processes in the ocean. In a continuum from the photic zone through the chemocline into deep anoxic sediments of the southern Black Sea, diagnostic quinones and inorganic geochemical parameters indicate niche segregation between redox processes and corresponding shifts in microbial community composition. Quinones specific for oxygenic photosynthesis and aerobic respiration dominate oxic waters, while quinones associated with thaumarchaeal ammonia-oxidation and bacterial methanotrophy, respectively, dominate a narrow interval in suboxic waters. Quinone distributions indicate highest metabolic diversity within the anoxic zone, with anoxygenic photosynthesis being a major process in its photic layer. In the dark anoxic layer, quinone profiles indicate occurrence of bacterial sulfur and nitrogen cycling, archaeal methanogenesis, and archaeal methanotrophy. Multiple novel ubiquinone isomers, possibly originating from unidentified intra-aerobic anaerobes, occur in this zone. The respiration modes found in the anoxic zone continue into shallow subsurface sediments, but quinone abundances rapidly decrease within the upper 50 cm below sea floor, reflecting the transition to lower energy availability. In the deep subseafloor sediments, quinone distributions and geochemical profiles indicate archaeal methanogenesis/methanotrophy and potentially bacterial fermentative metabolisms. We observed that sedimentary quinone distributions track lithology, which supports prior hypotheses that deep biosphere community composition and metabolisms are determined by environmental conditions during sediment deposition. Importance Microorganisms play crucial roles in global biogeochemical cycles. Yet, we have only a fragmentary understanding of the diversity

Geochemistry of uranium in the Black Sea

International Nuclear Information System (INIS)

Zhorov, V.A.; Bogushlavskij, S.G.; Babinets, A.E.; Solov'eva, L.V.; Kirchanova, A.I.; Kir'yanov, P.A.

1982-01-01

According to the results of expedition investigations on the base of SCOICH program (''Acade''Mmician Vernadsky'' and ichael Lomonosov'' shiptrips) main geometrical peculiarities of uranium distribution in deep water of the Black Sea including benthic and silt waters are studied. Sampling have been made from the surface layer across the whole width of the water and from benthic sediments (silt water). Uranium in samples has been determined by the adsorption-colorimetric method. Nonuniform uranium distribution (depending on water dynamics) over the basin area and across the whole width of water is established. Most of uranium is contained in the 0-500 m layer and in the eastern part of the sea. Uranium content decreases in depth, it is higher in the benthic water layer. It is shown that uranium decrease in a hydrogen-sulphide sea zone is conditioned by its reduction due to formation of more adsorption-active forms and effective sedimentation. Causes of differences in uranium content in silt waters have been found. High uranium concentrations in silt waters are confined to active sulphate reduction characterized by elevated values of pHsub(#betta#), alkalinity, Eh. In weak suphate reduction zones (pHsub(#betta#), Alsub(k) value decrease) in silt waters uranium content is lower as a result of sorption-active forms formation and their transition into the solid phase of sediments

Heavy metals distribution in the Dead Sea black mud, Jordan

International Nuclear Information System (INIS)

Momani, K.; El-Hasan, T.; Auaydeh, S.

2009-01-01

The concentrations of trace metals (Fe, Mn, Ni, Zn, Co, Cr, Cu and Pb) were investigated in the Dead Sea black mud and river sediments in the northern basin of the Dead Sea region, Jordan. The pH of the mud was slightly above 8 while it was around 6 for the seawater. All analyzed heavy metal content in the black mud, except Pb, was less than their contents in other types of mud. Tlis might be due to the effect of the mildly acideic pH of seawater, which would enhance the metal solubility or incorporation within salt mineral structure, rather than precipitation. The sequential extraction results showed that Ni and Co transferred into the carbonate fraction, Mn is found mostly as manganese-iron oxide, and the residual phase contained Cr, Cu, Fe,and Pb. This study illustrated that the black mud had low heavy metal contents, thus indicating low toxicity. additionally, it shows insignificance effect of the mixing of freshwater with seawater on the heavy metal contents in the black mud. (authors).

Quantification of microbial communities in subsurface marine sediments of the Black Sea and off Namibia

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Axel eSchippers

2012-01-01

Full Text Available Organic-rich subsurface marine sediments were taken by gravity coring up to a depth of 10 meters below seafloor at six stations from the anoxic Black Sea and the Benguela upwelling system off Namibia during the research cruises R/V Meteor 72/5 and 76/1, respectively. The quantitative microbial community composition at various sediment depths was analyzed using total cell counting, CARD-FISH and quantitative real-time PCR (Q-PCR. Total cell counts decreased with depths from 109 – 1010 cells /mL at the sediment surface to 107 – 109 cells /mL below one meter depth. Based on CARD-FISH and Q-PCR analysis overall similar proportions of Bacteria and Archaea were determined. The down core quantitative distribution of prokaryotic and eukaryotic small subunit ribosomal RNA genes as well as functional genes involved in different biogeochemical processes was successfully revealed by Q-PCR. Crenarchaeota and the bacterial candidate division JS-1 and the classes Anaerolineae and Caldilineae of the phylum Chloroflexi were as highly abundant as Archaea and Bacteria, respectively. Less abundant but detectable in most of the samples in high gene copy numbers were Eukarya and the Fe(III- and Mn(IV-reducing bacterial group Geobacteriaceae (off Namibia as well as the functional genes cbbL encoding for the large subunit of Rubisco, the functional genes dsrA and aprA of sulfate-reducers and the gene mcrA of methanogens. Overall the high organic carbon content of the sediments goes along with high cell counts and high gene copy numbers, as well as an equal abundance of Bacteria and Archaea.

Investigation of the shelf break and continental slope in the Western part of the Black Sea using acoustic methods

Science.gov (United States)

Dutu, F.; Ion, G.; Jugaru Tiron, L.

2009-04-01

The Black Sea is a large marginal sea surrounded by a system of Alpine orogenic chains, including the Balkanides-Pontides, Caucasus, Crimea and North Dobrogea located to the south, northeast, north and northwest, respectively (Dinu et al., 2005). The north-western part of the Black Sea is the main depocentre for sediment supply from Central Europe via the Danube River, but also from Eastern Europe through the Ukrainian rivers Dniepr, Dniestr and Southern Bug (Popescu et al., 2004). The shelfbreak is located at water depths of 120-140 m southward of the Danube Canyon, and up to 170 m northward of the canyon possibly due to recent faulting which is very common in this area. The continental slope is dissected by numerous canyons, each of which is fed by several tributaries. The Danube Canyon (also known as Viteaz Canyon) is a large shelf-indenting canyon located in the north-western Black Sea and connected to the youngest channel-levee system of the Danube Fan (Popescu et al., 2004). The acoustic methods are a useful way for investigate the shelf break and the continental slope giving us information about landslides on the continental slope, the topography of the investigated area, the sedimentary zones affected by instability and to quantify the geometry of the underwater landslides. The measurements made on the continental slope from north-western part of the Black Sea gave us the possibility to make a digital terrain model. After processing the data the model offer information about the main access ways of the sediments through gravitational slide on the submarines canyons, with forming of turbidity currents, debris flows and also other transport/transformation phenomena of the sediments on the continental slope like submarine landslides and submarine collapse. References Dinu, C., Wong, H.K., Tambrea, D., Matenco, L., 2005. Stratigraphic and structural characteristics of the Romanian Black Sea shelf. Tectonophysics 410, 417-435. Popescu, I., Lericolais, G., Panin

The Black Sea one decade after the Bucharest Convention an overview of the international activities in the Black Sea region

International Nuclear Information System (INIS)

Goektepe, G.

2002-01-01

The catastrophic degradation of the Black Sea in a period of four decade has been the major concern of the Black Sea countries and international communities since Bucharest Convention signed in 1992. The Black Sea Region has became a challenging international arena for political scientific and socio-economic activities. Intensive international programmes and establishment of governmental and Non Governmental Organizational structures of the 1990s including Black Sea Economic Cooperation (BSEC), Black Sea Environmental Programme(BSEP), Environmental Programme for the Danube River Basin, Marine Environmental Assessment of the Black Sea Region Technical Cooperation Programme by the IAEA and establishment of the Black Sea Commission Permanent Secretariat are some of the major international efforts of the past decade that emphasizes the multi-nationality and large dimension of the Black Sea environmental management issues. The environmental degradation of the Black Sea is briefly reviewed based on the BSEP reports and data available for land based pollution sources. The environmental risk of marine vessel accidents are indicated and environmental safety concern is emphasized under the current conditions of intense energy transportation projects in the Black Sea and Caspian regions. The international policy actions, co-operation issues and scientific programmes of the past decade are overviewed with emphasis on the international achievements. Concluding remarks include the vital importance of continuation of the international commitments and sharing the political, scientific and socio-economic responsibility on the transboundary environmental pollution, rehabilitation and the safety issues of the Black Sea

Secondary radioactive contamination of the Black Sea after Chernobyl accident: recent levels, pathways and trends.

Science.gov (United States)

Gulin, S B; Mirzoyeva, N Yu; Egorov, V N; Polikarpov, G G; Sidorov, I G; Proskurnin, V Yu

2013-10-01

The recent radionuclide measurements have showed that concentrations of the Chernobyl-derived (137)Cs and (90)Sr in the surface Black Sea waters are still relatively high, reaching 56 and 32 Bq m(-3), respectively. This is comparable or even exceeds the pre-Chernobyl levels (∼16 Bq (137)Cs and 22 Bq (90)Sr per m(3) as the basin-wide average values). The measurements have revealed that the Black Sea continues to receive Chernobyl radionuclides, particularly (90)Sr, by the runoff from the Dnieper River. An additional source of (90)Sr and (137)Cs was found in the area adjacent to the Kerch Strait that connects the Black Sea and the Sea of Azov. This may be caused by the inflow of the contaminated Dnieper waters, which come to this area through the North-Crimean Canal. The long-term monitoring of (137)Cs and (90)Sr concentration in the Black Sea surface waters and in the benthic brown seaweed Cystoseira sp., in comparison with the earlier published sediment records of the radionuclides, have showed signs of a secondary radioactive contamination, which has started to increase since the late 1990's. This may be the result of the combined effect of a higher input of radionuclides from the rivers in 1995-1999 due to an increased runoff; and a slow transport of the particulate bound radionuclides from the watersheds followed by their desorption in seawater from the riverine suspended matter and remobilization from the sediments adjacent to the river mouths. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sublacustrine river valley in the shelf zone of the Black Sea parallel to the Bulgarian coast

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Preisinger, A.; Aslanian, S.; Beigelbeck, R.; Heinitz, W.-D.

2009-04-01

The considered sublacustrine river valley is situated in the shelf zone of the Black Sea. It runs in parallel to the Bulgarian coast, was formed in the time period of the Younger Dryas (Preisinger et al., 2005), and features an inclination of about 0.5 m/km. An about 200 km long sediment wall separates the approximately 10 km broad river valley from the outside shelf zone. This wall was generated during the Older Dryas until the beginning of the Younger Dryas. Its shape was formed by transportation of water and sediment from the Strait of Kerch by a circulating rim current in the Black Sea and water as well as sediment flow of the Danube in direction to the Bosporus. New investigations of the sediments of this river valley were performed by utilizing a Sediment Echo Sounder (SES 2000). This Echo Sounder is a parametric sub-bottom profiler enabling a high resolution sub-bottom analyses. It is capable of penetrating sea beds up to more than 50 m of water depth. The received echo data are real-time processed. The signal amplitudes are valuated in context to a logarithmic scale and graphically visualized by means of a colorized echogram utilizing false colours ranging from red for a high to blue representing a low signal (W.-D. Heinitz et al., 1998). The highest signal (red) is given by the acoustic impedance of the boundary between sea water and river sediment. The echograms of the river valley depict spatially isolated (red) high-signal peaks, which are periodically repeated in vertical direction between the sediment surface and the bottom of the valley. The number of these high-signal parts increase with an increasing valley depth. Studying of the distribution of these peaks allows to draw conclusions regarding the content and composition of the sediment. This prediction of the sediment composition obtained by means of the SES 2000 was successfully verified by analyzing a gravity core taken near Nos Maslen (at 44 m water depth) with a particular focus on the water

Uranium in the Black Sea

International Nuclear Information System (INIS)

Babinets, A.E.; Zhorov, V.A.; Bezborodov, A.A.; Kobylyanskaya, A.G.; Solov'eva, L.V.; Urdenko, V.A.

1975-01-01

Water samples for uranium analysis have been collected over the entire Black Sea, from the surface to the sea floor. As distinct from the previously known facts, it has been established that the uranium content in different parts of the sea appears to vary both in extent and with depth. A behaviour of uranium is governed by redox conditions of the environment. A decrease in pH value of water to 7.5 and a change of Eh value from +0.4 to -0.2 v lead to reduction of U 6+ → U 4+ and ensure higher sorption properties of the solid phases. The reducing reaction is proved possible through the calculated data. It is shown that the rate of uranium isolation is increasing with depth and its content is going down. Using optical properties of water, a hydrogeochemical behaviour of organic matter and uranium in water thickness is explained. Role of organic matter and mineral components in the uranium deposition is described. Sorption of U 6+ ions on twelve components, which constitute a base of suspensions and floor sediments, has been also studied [ru

Black Sea challenges

International Nuclear Information System (INIS)

Drevet, J.F.

2008-01-01

In this month's European column, Jean-Francois Drevet examines the issues that arise for Europe from the Black Sea region. The Black Sea is increasingly becoming a crucial place of transit for hydrocarbon imports from the Caspian and Russia into the European Union. The considerable increase in this traffic raises both environmental problems (the risk of oil slicks) and issues of security of supply, on account of the economic and political fragility of some of the bordering or neighbouring states (Ukraine, Georgia, Armenia, Azerbaijan, Russia/Chechnya etc.). This is why, as Jean-Francois Drevet stresses, the European Union has been trying since the mid-1990's to claim a role in the management of the affairs of the region. With two bordering states (Rumania and Bulgaria) joining the EU in 2007, cooperation in the Black Sea has become a priority within the framework of the European Neighbourhood Policy, and this column delineates a number of the obstacles that still have to be surmounted. (author)

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.

Romanian contribution to the regional study of Black Sea radioactivity

International Nuclear Information System (INIS)

Bologa, S.

1993-01-01

In the Black Sea area, polluting mineral exploitation, abusive fishing, unrestricted shipping activities and dumping of toxic wastes were done. Pollutant load carried by the Danube and other northern rivers, such as: Dnieper, Dniester, Bug, etc to the Black Sea, industrial and municipal discharges of air and water pollutants, pollution from ship traffic (particularly in the Constanta harbour area) contributed to the ecological degradation of the sea. Radioactivity monitoring as well as radioecological research are part of environmental assessments and protection strategies in Romania. The Romanian contribution consisted in participation in research contracts and coordinated research programs with IAEA-Vienna/Marine Environment Laboratory-Monaco between 1987-1992, in the program 'Global Inventory of Radioactivity in the Mediterranean Sea' (GIRMED) launched by IAEA after the XXXIst Congress and General assembly of the International Commission for the Scientific Exploration of the Mediterranean Sea by the Committee of Marine Radioactivity in 1988 and in the Co-operative Marine Science Program for the Black Sea (CoMSBlack) trough its Working group on radiochemistry and radioecology. This group includes Bulgaria, Romania, Russia, Turkey, Ukraine, the Woods Hole Oceanographic Institution and the US Environmental Protection Agency. Natural and artificial radionuclide (K-40, Ac-228, Ra-226, Ru-106, Ag-110m, Cs-137 and, starting in 1992, Sr-90) space and time distribution data were used for computation of in situ distribution coefficients and concentration factors (CFs) as well as for external and internal dose assessments in the Romanian sector. CFs of marine sediments, seaweeds and molluscs were measured in laboratory conditions. (author)

Control of the geomorphology and gas hydrate extent on widespread gas emissions offshore Romania (Black Sea)

Science.gov (United States)

Riboulot, V.; Cattaneo, A.; Sultan, N.; Ker, S.; Scalabrin, C.; Gaillot, A.; Jouet, G.; Marsset, B.; Thomas, Y.; Ballas, G.; Marsset, T.; Garziglia, S.; Ruffine, L.; Boulart, C.

2016-12-01

The Romanian sector of the Black Sea deserves attention because the Danube deep-sea fan is one of the largest sediment depositional systems worldwide and is considered the world's most isolated sea, the largest anoxic water body on the planet and a unique energy-rich sea. Due to the high sediment accumulation rate, presence of organic matter and anoxic conditions, the Black sea sediment offshore the Danube delta is rich in gas and thus show BSR. The cartography of the BSR over the last 20 years, exhibits its widespread occurrence, indicative of extensive development of hydrate accumulations and a huge gas hydrate potential. By combining old and new datasets acquired in 2015 during the GHASS expedition, we performed a geomorphological analysis of the continental slope north-east of the Danube canyon that reveals the presence of several landslides inside and outside several canyons incising the seafloor. It is a complex study area presenting sedimentary processes such as seafloor erosion and instability, mass wasting, formation of gas hydrates, fluid migration, gas escape, where the imprint of geomorphology seems to dictate the location where gas seep occurs. . Some 1409 gas seeps within the water column acoustic records are observed between 200 m and 800 m water depth. No gas flares were detected in deeper areas where gas hydrates are stable. Overall, 93% of the all gas seeps observed are above geomorphological structures. 78% are right above escarpment induced by sedimentary destabilizations inside or outside canyons. The results suggest a geomorphological control of degassing at the seafloor and gas seeps are thus constrained by the gas hydrates stability zone. The stability of the gas hydrates is dependent on the salinity gradient through the sedimentary column and thus on the Black Sea recent geological history. The extent and the dynamics of gas hydrates have a probable impact on the sedimentary destabilization observed at the seafloor.

Coccolithophore assemblage response to Black Sea Water inflow into the North Aegean Sea (NE Mediterranean)

Science.gov (United States)

Karatsolis, B.-Th.; Triantaphyllou, M. V.; Dimiza, M. D.; Malinverno, E.; Lagaria, A.; Mara, P.; Archontikis, O.; Psarra, S.

2017-10-01

This study aims to presents the species composition of living coccolithophore communities in the NE Aegean Sea, investigating their spatial and temporal variations along a north-south transect in the area receiving the inflowing surface Black Sea Water (BSW) over the deeper Levantine Water (LW) layer. Coccolithophores in the area were relatively diverse and a total of 95 species over 3 sampling periods studied were recognized using Scanning Electron Microscope (SEM) techniques. R-mode hierarchical cluster analysis distinguished two coccolithophore Groups (I, IIa, IIb, IIc) with different ecological preferences. Emiliania huxleyi was the most abundant species of Group I, whereas Syracosphaera spp., Rhabdosphaera spp. and holococcolithophores were prevailing in the highly diversified Group II assemblages. Biometric analysis conducted on E. huxleyi coccoliths from Aegean water column and Black Sea sediment trap samples, indicated that during autumn, NE Aegean specimens in samples under BSW influence were featured by unimodal distribution concerning the coccolith relative tube width, with values similar to those provided by the Black Sea specimens. In early spring, coccoliths in the stations with increased BSW influx displayed a bimodal pattern of relative tube width with smaller values found mostly in the surface layers, while the distribution became again unimodal and dominated by larger values within the deeper LW layers. In the summer period, the typical LW holococcolithophore species (Group II) presented low cell numbers in the surface layer (huxleyi was almost absent in the NE Aegean during the summer sampling period.

A high-resolution paleosecular variation record from Black Sea sediments indicating fast directional changes associated with low field intensities during marine isotope stage (MIS) 4

Science.gov (United States)

Nowaczyk, Norbert R.; Jiabo, Liu; Frank, Ute; Arz, Helge W.

2018-02-01

A total of nine sediment cores recovered from the Archangelsky Ridge in the SE Black Sea were systematically subjected to intense paleo- and mineral magnetic analyses. Besides 16 accelerator mass spectrometry (AMS) 14C ages available for another core from this area, dating was accomplished by correlation of short-term warming events during the last glacial monitored by high-resolution X-ray fluorescence (XRF) scanning as maxima in both Ca/Ti and K/Ti ratios in Black Sea sediments to the so-called 'Dansgaard-Oeschger events' recognized from Greenland ice cores. Thus, several hiatuses could be identified in the various cores during the last glacial/interglacial cycle. Finally, core sections documenting marine isotope stage (MIS) 4 at high resolution back to 69 ka were selected for detailed analyses. At 64.5 ka, according to obtained results from Black Sea sediments, the second deepest minimum in relative paleointensity during the past 69 ka occurred, with the Laschamp geomagnetic excursion at 41 ka being associated with the lowest field intensities. The field minimum during MIS 4 is associated with large declination swings beginning about 3 ka before the minimum. While a swing to 50°E is associated with steep inclinations (50-60°) according to the coring site at 42°N, the subsequent declination swing to 30°W is associated with shallow inclinations of down to 40°. Nevertheless, these large deviations from the direction of a geocentric axial dipole field (I = 61 °, D = 0 °) still can not yet be termed as 'excursional', since latitudes of corresponding virtual geomagnetic poles (VGP) only reach down to 51.5°N (120°E) and 61.5°N (75°W), respectively. However, these VGP positions at opposite sides of the globe are linked with VGP drift rates of up to 0.2° per year in between. These extreme secular variations might be the mid-latitude expression of a geomagnetic excursion with partly reversed inclinations found at several sites much further North in Arctic

Influence of the Bottom Sediment Characteristics on the Bivalve Mollusk Anadara kagoshimensis Histopathology's Variability in the Northeastern Coast of the Black Sea

Science.gov (United States)

Kolyuchkina, G. A.; Budko, D. F.; Chasovnikov, V. K.; Chzhu, V. P.

2017-11-01

With increasing anthropogenic impact on the environment, investigations of organism's response to the contamination of natural habitats, are especially relevant. In the present study, we sought to identify the correlation between the bottom sediments and local variability in histopathology of Anadara kagoshimensis (Bivalvia) in four sites of the north-eastern coast of the Black Sea. Bottom sediment grain size, redox potential of pore water, heavy metals, benzo-α-pyrene and DDT concentrations have been used as characteristics of bottom sediments. Analysis of the data revealed differences in the geochemical background of the studied sites and the histopathological state of the molluscs from these areas. Among the 10 studied elements as well as benzo-α-pyrene and DDT, only Ni has shown an exceedance of statutory limits of concentration in bottom sediments. The study reveals a relationship between Ni concentration in the bottom sediments and frequency of heavy histopathologies in the molluscs. In addition to causes directly related to pollution, mild pathology may be influenced by "natural" causes; in particular, the high content of brown cells in the connective tissue of the digestive gland may be due to the age of molluscs.

Geochemistry and microbiology at gas hydrate and mud volcano sites in the black sea

Science.gov (United States)

Drews, M.; Schmaljohann, R.; Wallmann, K.

2003-04-01

We present geochemical and microbiological results which were obtained from sediments at gas hydrate and mud volcano sites in the Sorokin Trough (northern Black Sea, south east of the Crimean peninsula) at water depths of about 1800 to 2100 m during the METEOR cruise 52-1. The surface near sub-bottom accumulations of gas hydrates (occuring at depths of several meters or less beneath the sea floor) in the Black Sea are associated with numerous mud volcanos. At stations we investigated gas hydrates occurred below 10 cm to 100 cm with a significant influence on the sediment biochemistry. Analyses revealed high methane concentrations, anoxic and sulfidic conditions, a steep sulfate gradient, carbonate precipitation, and high anaerobic methane oxidation rates. In proximity of the so called Odessa mud volcano one investigated sampling station showed maximum methane oxidation rates in the depth horizon of a firm 2 cm thick carbonate crust layer, adhered to by a bacterial mat. This observation is taken to indicate that the bacteria are causing or mediating the crust formation by their anaerobic methane oxidation metabolism. The station was further characterised by two layers of gas hydrate fragments and lenses below 1 m depth. A 2 to 4 cm thick carbonate crust with attached bacterial mat from a Yalta mud vulcano sample (2124 m water depth) was investigated under the scanning electron microscope. The stiff gelatinous mat showed a dense and morphologically uniform population of rod shaped bacteria with only a few nests of coccoid cells. Purified mat material exhibited anaerobic methane oxidation activity. These mats resemble the type previously found in the shallow NW methane seep area of the Black Sea, where it covers carbonate chimneys. Samples from two sites atop the summit of the active but flat-topped Dvurechenskii mud volcano were characterised by very high methane oxidation rates (up to 563 nmol/cm3/d) at the sediment surface. Strong pore water gradients of chloride

Environmental policy in the north-eastern sector of the Black sea coast

Science.gov (United States)

Kosyan, Ruben; Godin, Evgenii; Kosyan, Alisa

2015-04-01

becomes crucial. For a long period of time the coast protective activity was concentrated on elimination of localized zones of washout, without consideration of lithodynamic system in which the protected area is located, that led to disturbance of sediments flows, and, consequently, to acceleration of abrasion on the related parts of the shore. Main technical solutions regarding coast protection constructions for creation of artificial beaches, are borrowed from the experience of coast protection (construction of bunas, breakwaters and wave walls) at Caucasus and Crimean shores of the Black Sea. Application of bunas and breakwaters is formally divided by the steepness of the underwater slope equal to 0.03. However, this division did not and does not have any physical grounds and is not confirmed by materials of study of surf zone's hydro- and lithodynamics. Types of constructions and their composition in the coastal protective complexes were assigned subjectively. Because of general deficit of the sediments, the free beaches with big length were difficult to create. It was neces- sary to build the sediment retaining constructions like bunas, on the landslide sections - underwater breakwaters. Thus, the beaches in the coast protective complexes were having a primary role, and the constructions - secondary.

Hydrocarbons in the suspended matter and the bottom sediments in different regions of the Black Sea Russian sector

Directory of Open Access Journals (Sweden)

I. A. Nemirovskaya

2017-08-01

Full Text Available Content and composition of hydrocarbons (mainly the aliphatic ones in the suspended matter and the bottom sediments in the Gelendzhik Bay, the Big Sochi water area, the Feodosiya Bay and the Black Sea central part are defined and compared with the total organic carbon and chlorophyll a contents. It is shown that the aliphatic hydrocarbon concentrations exceeding the background ones are found only in the coastal zone. Advancing to the pelagic zone is accompanied by sharp decrease of their concentrations. Petroleum and pyrogenic hydrocarbons are mainly manifested in the polycyclic aromatic hydrocarbons composition. Influence of construction of the Olympic facilities upon distribution of hydrocarbons in the Big Sochi water area was of short duration, and already by 2015 the aliphatic hydrocarbons concentration decreased, on the average, up to 24 µg/l in the surface waters, and up to 18 µg/g – in the bottom sediments. Accumulation of hydrocarbons took place in bottom sediments, where their concentrations exceeded the background ones in terms of dry weight. In the Gelendzhik Bay, their content reached 252 μg/g, and in the composition of organic carbon (Corg > 1 %, which may indicate the contamination of sediments with oil products. In the Feodosiya Bay their part in the composition of Corg did not exceed 0.73 % and was 0.35 % on average. Natural alkanes dominated in the composition of aliphatic hydrocarbons. The bottom sediments are characterized by the predominance of odd high-molecular terrigenous alkanes. The content of polycyclic aromatic hydrocarbons in the studied sediments was rather low: up to 31 ng/g in the Gelendzhik Bay, up to 348 ng/g in the Feodosiya Bay. These concentrations according to the EPA classification are considered background, or minor petroleum hydrocarbons increase the level of aliphatic hydrocarbons in water and sediments, thus creating a modern hydrocarbon background.

Phosphorus dynamics in and below the redoxcline in the Black Sea and implications for phosphorus burial

Science.gov (United States)

Dijkstra, N.; Kraal, P.; Séguret, M. J. M.; Flores, M. R.; Gonzalez, S.; Rijkenberg, M. J. A.; Slomp, C. P.

2018-02-01

Marine basins with oxygen-depleted deep waters provide a natural laboratory to investigate the consequences of anoxic and sulfidic (i.e. euxinic) conditions for biogeochemical processes in seawater and sediments. In this study, we investigate the dynamics of the key nutrient phosphorus (P) and associated elements such as manganese (Mn), iron (Fe) and calcium (Ca) in the euxinic deep basin of the Black Sea. By examining water column particles with scanning electron microscope - energy dispersive spectroscopy and synchrotron-based X-ray absorption spectroscopy, we show that Mn(III/IV)-P is the key form of particulate P in the redoxcline. Other forms of particulate P include organic P, Fe(III)-P, and inorganic polyphosphates. Most inorganic P particles that are formed in the redoxcline subsequently dissolve in the underlying sulfidic waters, with the exception of some particulate Fe(III)-P that accounts for <1% of all P settling onto the seafloor. Organic P is the dominant source of P to the sediment. Most of this organic P is degraded in the upper 2 cm of the sediment. Results of sequential extractions and a 33P radiotracer experiment point towards the formation of labile Ca-P and P adsorbed onto calcium-carbonate and clays and a role of these phases as a major sink of P in the sediment. The total P burial efficiency in the sediments is ∼27%, which is relatively high when compared to estimates for sediments in other euxinic basins such as the Baltic Sea (<12%). We suggest that the abundant presence of calcium carbonate may contribute to the more efficient sequestration of P in Black Sea sediments.

Black Sea Traffic and European Integration

Directory of Open Access Journals (Sweden)

Veselina Urucu

2012-10-01

Full Text Available The Black Sea is a major component of the MeditetmneanSea. It is a bridge between two continents and a factor of cohesionamong ancient neighbouring spaces of civilisation. Someof its geographical peculiatities make of it a half-closed sea betweenEurope and Asia. Its link with the Mediterranean is securedby the Bosphorus and the Dardanelles Straits and thencewith the planetaty ocean. So, the Black Sea ports represent actualgateways to the world for its tiverain countries. These portsboomed or waned in terms of the riverain regions' hist01y. After1990, and moreover after the Soviet Union fell apatt and newsovereign states came into being, the Pontic space has been undergoingmajor geopolitical changes. Traffic suffered radicalchanges, being governed by fresh criteria and directions. Thereis growing competition among the city-ports and, under the1992 Black Sea Economic Co-operation Treaty, new regionaldevelopment opportunities have been cropping up for the individualstates. Viewed at global scale, the Black Sea might play,if integrated into an adequate programme, an essential role ofcohesion and stability in a complex European zone with a histOtyfull of turmoil.

Determination of radioactivity levels and heavy metal concentrations in seawater, sediment and anchovy (Engraulis encrasicolus) from the Black Sea in Rize, Turkey.

Science.gov (United States)

Baltas, Hasan; Kiris, Erkan; Sirin, Murat

2017-03-15

Seawater, sediment and fish (anchovy) samples consumed in the Rize province of the Eastern Black Sea region of Turkey were collected from five different stations. The radioactivity levels ( 226 Ra, 232 Th, 40 K and 137 Cs) were determined in all the samples using a high-purity germanium detector. While 226 Ra, 232 Th and 40 K radionuclides were detected in all samples, the radionuclide concentration of 137 Cs, except for the sediment samples (mean activity is 9±1.4Bqkg -1 ), was not detected for the seawater and fish samples. The total annual effective dose rates from the ingestion of these radionuclides for fish were calculated using the measured activity concentrations in radionuclides and their ingested dose conversion factor. Also, the concentrations of some heavy metals in all the samples were determined. The activity and heavy metal concentration values that were determined for the seawater, sediment and fish samples were compared among the locations themselves and with literature values. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ion transport in deep-sea sediments

International Nuclear Information System (INIS)

Heath, G.R.

1979-01-01

Initial assessment of the ability of deep-sea clays to contain nuclear waste is optimistic. Yet, the investigators have no delusions about the complexity of the natural geochemical system and the perturbations that may result from emplacement of thermally-hot waste cannisters. Even though they may never be able to predict the exact nature of all these perturbations, containment of the nuclides by the waste form/cannister system until most of the heat has decayed, and burial of the waste to a sufficient depth that the altered zone can be treated as a black box source of dissolved nuclides to the enclosing unperturbed sediment, encourage them to believe that ion migration in the deep seabed can be modeled accurately and that our preliminary estimates of migration rates are likely to be reasonably realistic

Black Sea Bass genetic connectivity

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Microsatellite analysis of black sea bass was undertaken to determine magnitude and direction of mixing of black seabass across the Hatteras boundary, as well as...

Pyritization processes and greigite formation in the advancing sulfidization front in the Upper Pleistocene sediments of the Black Sea

DEFF Research Database (Denmark)

Neretin, LN; Bottcher, ME; Jørgensen, BB

2004-01-01

Pyritization in late Pleistocene sediments of the Black Sea is driven by sulfide formed during anaerobic methane oxidation. A sulfidization front is formed by the opposing gradients of sulfide and dissolved iron. The sulfidization processes are controlled by the diffusion flux of sulfide from above...... and by the solid reactive iron content. Two processes of diffusion-limited pyrite formation were identified. The first process includes pyrite precipitation with the accumulation of iron sulfide precursors with the average chemical composition of FeSn (n = 1.10-1.29), including greigite. Elemental sulfur...... and polysulfides, formed from H,S by a reductive dissolution of Fe(Ill)-containing minerals, serve as intermediates to convert iron sulfides into pyrite. In the second process, a "direct" pyrite precipitation occurs through prolonged exposure of iron-containing minerals to dissolved sulfide. Methane-driven sulfate...

Predictive isotopic biogeochemistry of lipids from the Black Sea and Cariaco Trench

International Nuclear Information System (INIS)

Freeman, K.H.; Hayes, J.M.; Wakeham, S.G.

1991-01-01

Carbon isotopic compositions of autotrophic organisms can be predicted based on recently established relationships between [CO 2 (aq)] and var-epsilon p , the isotopic fractionation accompanying carbon fixation. In both the Black Sea and the Cariaco Trench, where [CO 2 (aq)] values are known and δ values for hydrocarbons were recently determined, predicted biomass δ values can be compared to those of biomarkers extracted from POM and sediment samples. The agreement is good, although a 5 per-thousand range in δ values is observed for the lipids, which may be due to ecological factors or to contributions from organisms that assimilate HCO 3 -. Lycopane and pentamethyleicosane apparently derive from planktonic organisms. Diploptene in the Black Sea apparently is derived from chemoautotrophic bacteria living at the oxic/anoxic interface. Some odd-C, long-chain n-alkanes have planktonic δ values, and the authors suggest they are not strict terrestrial indicators

Nitrogen budget of the northwestern Black Sea shelf inferred from modeling studies and in situ benthic measurements

NARCIS (Netherlands)

Grégoire, M.; Friedrich, J.

2004-01-01

A 3D eddy-resolving coupled biogeochemical-hydrodynamical model and in situ observations are used to investigate benthic processes on the Black Sea's NW shelf. Measurements of benthic fluxes (oxygen, nutrients, redox compounds) with in situ flux chambers are analyzed in regard to sediment dynamics

Gelationous Organism (Macrozooplankton in the Black Sea and Effects

Directory of Open Access Journals (Sweden)

Zekiye BİRİNCİ ÖZDEMİR

2017-06-01

Full Text Available It is important problem as ecological, invasion of the marine systems by the gelatinous organism that distributed natural balance. Black Sea ecosystem has been changed critical level by the some causes such as marine pollution, eutrophication, climate change, overfishing, invasive gelatinous organisms. Effect in the ecosystem of gelatinous organisms occurred especially with collapsed of Black Sea anchovy (Engraulis encrasicolus stock and fishery production. In the study, gelatinous organism species, important for Black sea, and its effects in the Black sea ecosystem were presented.

Sediments in Arctic sea ice: Implications for entrainment, transport and release

Science.gov (United States)

Nurnberg, D.; Wollenburg, I.; Dethleff, D.; Eicken, H.; Kassens, H.; Letzig, T.; Reimnitz, E.; Thiede, Jorn

1994-01-01

Despite the Arctic sea ice cover's recognized sensitivity to environmental change, the role of sediment inclusions in lowering ice albedo and affecting ice ablation is poorly understood. Sea ice sediment inclusions were studied in the central Arctic Ocean during the Arctic 91 expedition and in the Laptev Sea (East Siberian Arctic Region Expedition 1992). Results from these investigations are here combined with previous studies performed in major areas of ice ablation and the southern central Arctic Ocean. This study documents the regional distribution and composition of particle-laden ice, investigates and evaluates processes by which sediment is incorporated into the ice cover, and identifies transport paths and probable depositional centers for the released sediment. In April 1992, sea ice in the Laptev Sea was relatively clean. The sediment occasionally observed was distributed diffusely over the entire ice column, forming turbid ice. Observations indicate that frazil and anchor ice formation occurring in a large coastal polynya provide a main mechanism for sediment entrainment. In the central Arctic Ocean sediments are concentrated in layers within or at the surface of ice floes due to melting and refreezing processes. The surface sediment accumulation in central Arctic multi-year sea ice exceeds by far the amounts observed in first-year ice from the Laptev Sea in April 1992. Sea ice sediments are generally fine grained, although coarse sediments and stones up to 5 cm in diameter are observed. Component analysis indicates that quartz and clay minerals are the main terrigenous sediment particles. The biogenous components, namely shells of pelecypods and benthic foraminiferal tests, point to a shallow, benthic, marine source area. Apparently, sediment inclusions were resuspended from shelf areas before and incorporated into the sea ice by suspension freezing. Clay mineralogy of ice-rafted sediments provides information on potential source areas. A smectite

Contemporary radioecological state of the North-western Black Sea and the problems of environment conservation

International Nuclear Information System (INIS)

Tereshchenko, N.N.; Mirzoyeva, N.Yu.; Gulin, S.B.; Milchakova, N.A.

2014-01-01

Highlights: • Contamination of the ecosystem components by the radioactive isotopes 137 Cs, 90 Sr, 239, 240 Pu. • The maps of the temporal–spatial change in distribution of isotopes are submitted. • Zones with an increased ability to accumulate these radioactive pollutants were revealed. • Estimations of the flows of elimination of the radionuclides into the bottom sediments were carried out. • Assessment of dose rates formed by 90 Sr, 137 Cs and 239,240 Pu for Black Sea hydrobionts was obtained. - Abstract: Review is devoted to the analysis of a radioecological situation in the North-western Black Sea and concerns the levels of contamination of the components of an ecosystem by the main artificial radioactive isotopes ( 90 Sr, 137 Cs, 239,240 Pu). The long-term accumulation trends of these radionuclides were analyzed in components of the Black Sea ecosystem after the Chernobyl nuclear power plant accident. Zones that have an increased ability to accumulate these radioisotopes were revealed. The assessment of irradiation dose rates formed by 90 Sr, 137 Cs and 239,240 Pu in Black Sea hydrobionts was obtained. The strategy for biodiversity conservation and sustainable management of natural resources should include monitoring of the radioecological state of the marine ecosystems, and the formation of a complex of biogeochemical criteria for assessment of an ecological situation in the sea. This approach is important for marine protected areas, since it allows the formation of a basis for scientific and practical function

REGIONAL COOPERATION IN THE BLACK SEA BASIN

Directory of Open Access Journals (Sweden)

Anastasiia GAVUIK

2015-07-01

Full Text Available Topicality. The Black Sea region is situated in a very important geopolitical manner. Consequently, a large-scale regional collaboration becomes possible within the Black Sea zone and countries get appropriate conditions to launch their activity in this context. Aim: The body of the article is going to analyze the BSEC as one of the most successful regional organizations in the Black Sea area. The paper aims to provide an overview of the regional players’ activity in the framework of the BSEC which are involved in sustaining and strengthening of this organization and also in continuing the reform process in it, developing in the same time relations of cooperation with the EU and other regional initiatives. Methods. This article embraces a row of different scientific methods of data analysis, predictive analytics, historical and statistical overview, descriptive method, case study etc. Results. The countries from the Black Sea basin are the most vulnerable to potential risks and shocks due to the instability of the region. This requires the interstate cooperation in the Black Sea area with no tradition in this field several decades ago. In the same time, countries like Turkey, Romania or Russia aspire to play the role of the regional leader, which can cause regional rivalries. With the help of the regional cooperation and the BSEC in particular, regional countries could learn how to work together for the common benefit. The creation of stable markets, interconnected and transparent regional organizations and initiatives would largely contribute to the security and stability of the Black Sea region.

Source identification of hydrocarbon contaminants and their transportation over the Zonguldak shelf, Turkish Black Sea

Science.gov (United States)

Unlu, S.; Alpar, B.

2009-04-01

Under great anthropogenic pressure due to the substantial freshwater input from the surrounding industrial and agricultural areas, especially central and middle-Eastern Europe, the Black Sea basin is ranked among the most ecologically threatened water bodies of the world. Oil levels are unacceptable in many coastal areas perilously close to polluted harbors and many river mouths; the places presenting the highest levels of bio-diversity and having a high socio-economic importance due to human use of coastal resources. There are about sixty sources of pollution which resulted in "hot spots" having disastrous impacts on sensitive marine and coastal areas and needing immediate priorities for action. Beyond such land-based sources, trans-boundary pollution sources from Black Sea riparian countries, heavy maritime traffic, particularly involving petroleum transports and fishing boats, and the improper disposal of ballast and bilge waters and solid waste are also important marine sources of pollution. Found in fossil fuels such as Polycyclic Aromatic Hydrocarbons are generated by incomplete combustion of organic matter. In order to estimate their distribution in sediment and their sources, they were monitored from the bottom samples offshore the Zonguldak industry region, one of the most polluted spots in the Turkish Black Sea. There the budget of pollutants via rivers is not precisely known due to an evident lack of data on chemical and granulometric composition of the river runoff and their fluxes. Therefore the marine sediments, essential components of marine ecosystems, are very important in our estimating the degree of the damage given to the ecosystem by such inputs. Realization of the sources and transport of these contaminants will be a critical tool for future management of the Zonguldak industry region and its watershed. The sea bottom in study area is composed of mainly sand and silt mixtures with small amount of clay. Geochemical analyses have shown that oil

Biomarker and 16S rDNA evidence for anaerobic oxidation of methane and related carbonate precipitation in deep-sea mud volcanoes of the Sorokin Trough, Black Sea

NARCIS (Netherlands)

Stadnitskaia, A.; Muyzer, G.; Abbas, B.; Coolen, M.J.L.; Hopmans, E.C.; Baas, M.; Weering, T.C.E. van; Ivanov, M.K.; Poludetkina, E.; Sinninghe Damsté, J.S.

2005-01-01

Many mud volcanoes were recently discovered in the euxinic bottom waters of the Sorokin Trough (NE Black Sea). Three of them, i.e., NIOZ, Odessa, and Kazakov, were selected for a detailed biogeochemical investigation. Four methane-related carbonate crusts covered with microbial mats, and sediments

Effect of hypoxia on benthic nutrient fluxes in the northwestern Black Sea

Science.gov (United States)

Friedrich, J.

2012-04-01

, ammonia release from the sediments has been significantly higher than in oxic conditions, while no significant differences were detected in nitrate effluxes. This may be explained by dissimilatory reduction of the nitrate stored in large sulphate reducing bacteria like Beggiatoa (DNRA) leading to high fluxes of ammonia. DNRA might be an important recycling pathway of nitrogen during hypoxia on the Black Sea shelf. Hypoxia triggers also phosphate efflux from the sediment, the flux being marginally significantly higher than during oxic conditions where phosphate adsorbs to iron and manganese oxihydroxides. No clear pattern has been found in the N:P ratios of the nutrient efflux. This study shows that hypoxia supports higher ammonia and phosphate effluxes from the sediment than oxic conditions, making the sediment to a larger source of nutrients for benthic and pelagic productivity. Avoiding man-made hypoxia or anoxia in coastal seas is crucial for maintaining a balanced and functioning ecosystem.

Environmental pollution of the Black Sea: A search for answers

International Nuclear Information System (INIS)

Fabry, V.; Osvath, I.; Froehlich, K.

1993-01-01

The Black Sea region governments have initiated a regional approach to the management and protection of the marine environment supported by research at national and international levels. Environmental problems in the Black Sea are serious. The Sea's shallow, mixed surface waters receive river discharges which are heavily loaded with nutrients containing nitrogen and phosphorus and contaminated with industrial and mining wastes. In addition, coastal industries appear to discharge wastes directly into the sea with little or no treatment. Thus the water quality of the life-supporting surface layer has seriously deteriorated. Eutrophication (an enrichment in nutrients) presently prevails in many parts of the Black Sea. It has dramatically changed the marine food chain, thus contributing to the demise of the Black Sea fishery and, especially in the northwestern region, to its diminished amenity value. Other factors also are at work, including changes in the hydrological balance, overfishing, and chemical pollution. Following the Chernobyl accident in 1986, riparian countries further identified radioactive pollution as having a high priority. This article looks at major aspects of the state of the Black Sea's environment, and outlines the potential of, and first results derived from, the use of isotope tracers in Black Sea studies. It further discusses IAEA initiatives to join concerted international actions directed towards rehabilitation of the Black Sea environment. 1 fig., 3 tabs, 2 maps

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

Sedimentation rate in Ariake Sea

International Nuclear Information System (INIS)

Momoshima, Noriyuki; Nishio, Souma; Honza, Eiichi

2004-01-01

The Ariake Sea is a shallow and almost enclosed sea located in western Kyushu, Japan with an area of about 1,700 km 2 and the deepest up to 30 m at north area. The most inner part of the bay area is very shallow and during low tide big mudflats tideland appears and extends up to several km. The tidal range is the highest in Japan with a maximum of about 6 m. The area is one of Japan's most important area for fishery, with over 40% of the total seaweed production in Japan In the year 2001, due to environmental conditions, the seaweed population decreased substantially with a production drop of about 50%. This was caused by an earlier winter outbreak of red tide that affected the seaweed quality. One proposed cause for this decline might be the land reclamation project in the western part of Ariake Sea, Isahaya Bay. This project started in April 1997 were more than 3,000 ha of the bay where closed by a 7 km long seawall. Contaminated water is regularly discharged from the reservoir inside the dike, which have resulted in changes in water flows and perhaps a decrease in tidal range. In 2002, the gates at the dike were open for two months for a survey campaign and the seaweed harvest in the winter 2002-2003 was quite good. However, the problem may be linked to totally different causes, e.g. increase in industrial pollution discharge, chemicals used in the disinfection methods of washing seaweed, or change in water pH after the volcanic eruptions of the Unzen mountain in 1992 and 1993. The purpose of the research is to elucidate present condition of the Ariake Sea and past history using by radiometric methods, and obtained useful information will resolve the environmental status of Ariake Sea and give us answers way to save the Ariake Sea. Sea sediment cores were taken on board in 2003 at several points covering the Ariake sea. Two cores taken in inner area of the sea were sectioned at every 2 cm intervals and subjected to gamma spectrometry to determine sedimentation

Arsenic in sediments from the southeastern Baltic Sea

International Nuclear Information System (INIS)

Garnaga, Galina; Wyse, Eric; Azemard, Sabine; Stankevicius, Algirdas; Mora, Stephen de

2006-01-01

Arsenic occurs as a persistent constituent in many of the chemical weapons dumped into the Baltic Sea; it can be used as an indicator of leakage and dispersal of released munitions to the marine environment. Total arsenic was analysed in sediment samples taken from the Lithuanian economic zone in the Baltic Sea, which included samples from the chemical munitions dumpsite in the Gotland Basin and national monitoring stations in the southeastern Baltic Sea. Arsenic concentrations in sediments ranged from 1.1 to 19.0 mg kg -1 , with an average of 3.4 mg kg -1 . Although there was evidence of slightly elevated arsenic content in sediments near the weapons dumpsite, arsenic concentrations were nevertheless quite low relative to other investigations in the Baltic and North Seas. - Arsenic concentrations in sediments near chemical weapons dumpsites were only slightly elevated

Present level of contaminants in the Romanian Black Sea sector

International Nuclear Information System (INIS)

Bologa, A.S.; Apas, M.; Cociasu, A.; Cuingioglu, E.; Patrascu, V.; Pecheanu, I.; Piescu, V.; Popa, L.

1999-01-01

The assessment of environmental quality in the Romanian Black Sea sector is being constantly made by the Romanian Marine Research Institute (RMRI) within the National Integrated Monitoring System. The contamination of the marine environment is expressed by considering four chemical and a biological parameter: nutrients (N-NO 2 , N-NO 3 , N-NH 4 , P-PO 4 , organic P, Si-SiO 4 ), heavy metals (Mn, Fe, Cu, Cd, Pb), artificial radionuclides ( 90 Sr, 137 Cs), total hydrocarbons, parasite and saprophyte fungi in sediments, sea water and/or biota. Present levels of contaminants are discussed as to their historical evolution during the last few years or decades. Inorganic N and P concentrations still exceed three to five times those before eutrophication started to intensify in the early '70s. Practical uses of results by national and regional authorities are discussed. (author)

Age-dependent mixing of deep-sea sediments

International Nuclear Information System (INIS)

Smith, C.R.; Maggaard, L.; Pope, R.H.; DeMaster, D.J.

1993-01-01

Rates of bioturbation measured in deep-sea sediments commonly are tracer dependent; in particular, shorter lived radiotracers (such as 234 Th) often yield markedly higher diffusive mixing coefficients than their longer-lived counterparts (e.g., 210 Pb). At a single station in the 1,240-m deep Santa Catalina Basin, the authors document a strong negative correlation between bioturbation rate and tracer half-life. Sediment profiles of 234 Th (half-life = 24 days) yield an average mixing coefficient (60 cm 2 y -1 ) two orders of magnitude greater than that for 210 Pb (half-life = 22 y, mean mixing coefficient = 0.4 cm 2 y -1 ). A similar negative relationship between mixing rate and tracer time scale is observed at thirteen other deep-sea sites in which multiple radiotracers have been used to assess diffusive mixing rates. This relationship holds across a variety of radiotracer types and time scales. The authors hypothesize that this negative relationship results from age-dependent mixing, a process in which recently sedimented, food-rich particles are ingested and mixed at higher rates by deposit feeders than are older, food-poor particles. Results from an age-dependent mixing model demonstrate that this process indeed can yield the bioturbation-rate vs. tracer-time-scale correlations observed in deep-sea sediments. Field data on mixing rates of recently sedimented particles, as well as the radiotracer activity of deep-sea deposit feeders, provide strong support for the age-dependent mixing model. The presence of age-dependent mixing in deep-sea sediments may have major implications for diagenetic modeling, requiring a match between the characteristic time scales of mixing tracers and modeled reactants. 102 refs., 6 figs., 5 tabs

On the Bioeconomic potential of the Black Sea

Science.gov (United States)

Gomoiu, Marian-Traian

2015-04-01

The paper is a plea for the need to engage in more intensive researches on the Black Sea region bioeconomy so that they should keep pace with the researches taking place in other European seas. Bioeconomy offers Europe a unique opportunity to address complex inter-connected challenges, while achieving economic growth. Bioeconomy refers to the set of economic activities relating to the invention, development, production and use of biological products and processes. According to the European Commission, bioeconomy can be found in societal challenge category entitled "Food security, sustainable agriculture and forestry, marine, maritime and inland water research, and the Bioeconomy" (http://ec.europa.eu/research/bioeconomy/h2020/index_en.htm); a transition is needed towards an optimal and renewable use of biological resources and towards sustainable primary production and processing systems. The author makes a brief overview of the European preoccupations concerning scientific research into bioeconomy and, equally, presents Romanian thinking in the field, launched several decades ago, but never applied and developed in practice. In 1933 Dr. Gr. Antipa, former outstanding student of Ernst Haeckel at Jena, expounded his conception of general biology and the biological structure of the Black Sea introducing the concepts of "biosociology" and "bioeconomy", drawing conclusions on the natural mechanism of fish production in this sea and specifying the determining factors in functioning. Antipa notes the lack of uniformity of the living conditions in the Black Sea and draws conclusions based on indices and faunal aspects found in different areas and at different depths: 1. The Black Sea, to an even greater extent than the Baltic Sea, with which it has some similarity both of them having a continuous surface and homogeneous appearance, is divided into more zones or biotypes, bounded horizontally and vertically - i.e. depending on areas and depths - each with distinct and well

Radioactivity levels in some sediment samples from Red Sea and Baltic Sea

International Nuclear Information System (INIS)

Salahel Din, K.; Vesterbacka, P.

2012-01-01

Levels of 226, 228 Ra, 232 Th, 210 Pb, 210 Po and 40 K in sediments from four monitoring areas, El Hamraween and Ras El Behar (Red Sea (Egypt)) and LL3A and JML (Baltic Sea (Finland)), have been investigated using alpha and gamma spectrometry. The average activity concentrations were 238±4 Bq kg -1 ( 226 Ra), 215±11 Bq kg -1 ( 210 Pb) and 311±18 Bq kg -1 ( 210 Po) for El Hamraween area. In Ras El Behar area, the corresponding values were 16±0.4, 18±1 and 20±5 Bq kg -1 , respectively. The activity concentrations for 226 Ra, 210 Pb and 210 Po (uranium series) in El Hamraween bottom sediment are much high compared with those in Ras El Behar area, which indicates the enhanced levels due to the activities of phosphate mining and shipment operations in El Hamraween area. Excluding the influence of phosphate mining activities, it can be concluded that the levels of radioactivity in Baltic Sea sediments are higher than those in Red Sea sediments. (authors)

ECOLOGICAL SAFETY OF CITIZENS OF RECREATIONAL ZONES OF THE BLACK SEA

Directory of Open Access Journals (Sweden)

Г. Білявський

2012-04-01

Full Text Available The article is devoted to meaningfulness estimation of ecological control of sea aquatory in forming ofsafety ecological conditions for citizens of the Black Sea. The pecularity and the role of technogenic pollution ofsea aquatory of the Black Sea are estimated. The degrees of ecological safety and negative influences of technogenicobjects on people living in the Black Sea coast are defined. The reccomendations for ecologization of recreationalzones of the Black Seat are characterized. The main goal of the work is the ecological estimation of livingconditions for sitizens in the Black Sea on the bases of using of methodology of complex searching andmarking of protecting laws

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.

Radiotracers in the Black Sea: A Tool for Marine Environmental Assessments

International Nuclear Information System (INIS)

Gulin, S.B.; Egorov, V.N.; Polikarpov, G.G.; Stokozov, N.A.; Mirzoeva, N.Yu.; Tereshenko, N.N.; Gulina, L.V.; Proskurnin, V.Yu.; Osvath, I.

2011-01-01

Owing to its geographical location, the Black Sea has been one of the marine basins most contaminated with artificial radioactivity. During the pre-Chernobyl period, the main source of radioactive contamination of the Black Sea was the global fallout from the atmospheric nuclear weapon tests, which peaked in 1962 before the 1963 Test Ban Treaty was signed between the main nuclear states. As maximum global fallout was observed within the 40-50 o N latitude band that runs exactly across the Black Sea, this semi enclosed water body received high levels of the fallout radionuclides derived from the atmospheric weapons testing. Being a closest marine body to the Chernobyl site, the Black Sea and its broad drainage areas have received substantial amounts of the long-lived artificial radionuclides, particularly 90 Sr, 137 Cs, and plutonium isotopes, released into the atmosphere from the damaged nuclear reactor and delivered with the air masses moving south- and westward from the accident area. Besides direct atmospheric deposition, the Black Sea received (and continues to receive) additional radioactive input by river runoff, particularly to its northwestern area from the Danube and Dnieper Rivers. Resulting from contribution of the above-mentioned sources of radioactive contamination of the Black Sea, the 90 Sr concentration in its water ranks second after the Irish Sea, and third after the Baltic Sea with respect to 137 Cs concentration in seawater. Overview of results. Extensive radioecological studies performed during the last decades have showed that post-Chernobyl evolution and levels of man-made radioactivity in the Black Sea were governed, except radioactive decay, by the large-scale oceanographic, biogeochemical and ecological processes, which control the self-cleaning of the Black Sea environments against the radioactive contamination: first of all the vertical water mixing, which dilutes the surface radionuclide concentrations, the loss through the Bosporus

Possibilities of Production and Storage of Hydrogen in the Black Sea

International Nuclear Information System (INIS)

Mehmet Haklidir; Fusun Servin Tut; Sule Kapkin

2006-01-01

Black Sea, a highly-isolated inland sea, is the largest anoxic zone in the world. Since the hydrogen sulphide zone was discovered in early 19. century in the Black Sea, it has been adopted that there is no life in the depths of the Black Sea and there are only bacteria live in the hydrogen sulphide layer. High content of organic matter, with maximum processes of bacterial sulfate reduction is the major source of this hydrogen sulphide zone. Hydrogen sulphide is one of the most poisonous gases in the world but it has great economic value to obtain hydrogen via dissociated into hydrogen and sulphur. Thus the Black Sea is not only has a serious environmental contamination but also has potential source of hydrogen energy, if a decomposition process can be developed. In this study, the sources of hydrogen sulphide, environmental impact of hydrogen sulphide in the Black Sea, the available techniques of hydrogen production from hydrogen sulphide and the possibilities of hydrogen storage by the natural sources in the Black Sea have been investigated. (authors)

Black shale deposition during Toarcian super-greenhouse driven by sea level

Science.gov (United States)

Hermoso, M.; Minoletti, F.; Pellenard, P.

2013-12-01

One of the most elusive aspects of the Toarcian oceanic anoxic event (T-OAE) is the paradox between carbon isotopes that indicate intense global primary productivity and organic carbon burial at a global scale, and the delayed expression of anoxia in Europe. During the earliest Toarcian, no black shales were deposited in the European epicontinental seaways, and most organic carbon enrichment of the sediments postdated the end of the overarching positive trend in the carbon isotopes that characterises the T-OAE. In the present study, we have attempted to establish a sequence stratigraphic framework for Early Toarcian deposits recovered from a core drilled in the Paris Basin using a combination of mineralogical (quartz and clay relative abundance) and geochemical (Si, Zr, Ti and Al) measurements. Combined with the evolution in redox sensitive elements (Fe, V and Mo), the data suggest that expression of anoxia was hampered in European epicontinental seas during most of the T-OAE (defined by the positive carbon isotope trend) due to insufficient water depth that prevented stratification of the water column. Only the first stratigraphic occurrence of black shales in Europe corresponds to the "global" event. This interval is characterised by >10% Total Organic Carbon (TOC) content that contains relatively low concentration of molybdenum compared to subsequent black shale horizons. Additionally, this first black shale occurrence is coeval with the record of the major negative Carbon Isotope Excursion (CIE), likely corresponding to a period of transient greenhouse intensification likely due to massive injection of carbon into the atmosphere-ocean system. As a response to enhanced weathering and riverine run-off, increased fresh water supply to the basin may have promoted the development of full anoxic conditions through haline stratification of the water column. In contrast, post T-OAE black shales during the serpentinum and bifrons Zones were restricted to epicontinental

Determination of wave energy potential of black sea

NARCIS (Netherlands)

Bingölbali, Bilal; Akpınar, Adem; van Vledder, G.P.; Lynett, P.

2016-01-01

This study aims to assess wave energy potential and its long-term spatial and temporal characteristics in the Black Sea within the TUBITAK research project (Akpınar et al., 2015). With this purpose, a wave model (SWAN model version 41.01 driven by the CFSR winds) over the entire Black Sea was

What is the pollution status of North Sea sediments?

International Nuclear Information System (INIS)

Chapman, P.M.; Heip, C.; Cofino, W.

1993-01-01

A March 1990 international sea-going workshop in Bremerhaven, Germany provided the opportunity to conduct detailed sediment toxicity testing in concert with studies of fish histopathology, bioaccumulation, benthic community structure, and sediment chemical contamination in the North Sea. Two gradients of sediment chemical contamination were tested, one from an abandoned oil platform and the other from the mouth of the Elbe River northward to the Dogger Bank. Using a preponderance of evidence approach, it was determined that sediments nearest the Elbe are moderately polluted (pollution is defined as contamination, toxicity, and community alteration) and that sediments offshore and at the Dogger Bank are unpolluted. Sediments nearest the oil platform showed evidence for a low level of pollution, but there was no evidence of pollution 125 m from the platform. The results suggest the testable hypothesis that North Sea sediments away from point sources of pollution such as coastal areas and drilling platforms are presently not polluted. 46 refs., 2 figs., 6 tabs

Black Sea Energy Security - Present and Future

Directory of Open Access Journals (Sweden)

Florinel Iftode

2011-05-01

Full Text Available We chose this theme to highlight the need for continuous and sustained human society to secure energy resources needed to survive, needs reflected in an increasingly in recent years in the strategies adopted at both states, as at the level of international organizations. Achieving security and stability in the wider Black Sea area has been among the priorities of each country's interests in this region. In this context, state and non-state actors were being called to come up with new solutions to achieve those interests. Certainly not in all cases the negotiations were completed or not yet found a generally accepted formula for others to apply, but most of them show off their values. The main environmental threats to security environment in the Black Sea region are represented by ethnic conflicts and territorial secessionism. A significant contribution to the security environment of the Black Sea region has the phenomenon of globalization, which in this region is manifested by a steady increase in traffic and volume of shipping passage of communication, which largely affects the security in the region. Globalization and the need for energy resources in the Black Sea was an important area not only as energy transport route, but as a potential supplier of material energy (oil and natural gas. Black Sea Basin can be stabilized and secured only by the will and input from all States and interested international organizations in pragmatic and effective institutional frameworks, meant to promote and protect the common interests of countries decided to participate in actions aimed at ensuring a stable environment security.

The performance of the Black Sea Commission as a collaborative governance regime

NARCIS (Netherlands)

Avoyan, Emma; Tatenhove, van J.P.M.; Toonen, H.M.

2017-01-01

It is often claimed that the Black Sea is one of the most degraded seas in the world. Management to rehabilitate the Black Sea requires cooperation between the coastal countries to be successful. However, regional cooperation in the Black Sea is poorly coordinated and lack concrete outcomes. This

Chemical composition of sediments from White Sea, Russian Arctic

Science.gov (United States)

Gamza, Olga; Shevchenko, Vladimir; Novigatsky, Aleksandr

2010-05-01

The White Sea, the only Russian inland sea, is located on the north of outlying districts of the European part of Russia, belongs to Arctic Ocean. Area of water of sea occupies about 90 tousend square kilometers. The sea can be divided into some general parts: neck, funnel, basin and 4 Bays: Dvina Bay, Kandalaksha Bay, Mezen Bay and Onega Bay. The purpose of this work was geochemical mapping of the surface sediments of this area. The main tasks were: compilation data base of element composition of the surface sediments, geochemical mapping of each element, research of the anormal concentration of elements on the surface. To detect the content of chemical elements several methods were used: atomic absorption spectrometry (P.P. Shirshov Institute of Oceanology); neutron activation analysis (Vernadsky Institute of Geochemistry and Analytical Chemistry), total and organic carbon analysis, photometric method to detection Si, Al, P (P.P. Shirshov Institute of Oceanology). Bulk composition is one of the fundamental characteristics of sediments and bottom deposites of modern basins. Coarse-grained sediments with portion of pelitic component 80%). Character of elements distribution correlates with facial distribution of sediments from White Sea. According to litologic description, bottom surface of Dvina Bay is practically everywhere covered by layer of fine-grained sand. In the border area between Dvina Bay and White Sea basin on terraced subwater slope aleurite politic silts are abundant. They tend to exhange down the slope to clay silts. In Onega Bay fractions of non-deposition are observed. They are characterized by wide spread of thin blanket poorgraded sediments, which are likely to be relic. Relief of Kandalakscha Bay bottom is presented as alternation of abyssal fosses (near 300 m) with silles and elevations (roof owning to diagenetic contraction. Authors thank academic Lisitsyn for encourage, Andrey Apletalin for valuable help, and everybody, who helped in field

The Vertical Distribution of Sediment Archaeal Community in the “Black Bloom” Disturbing Zhushan Bay of Lake Taihu

Science.gov (United States)

Fan, Xianfang; Xing, Peng

2016-01-01

Using the Illumina sequencing technology, we investigated the vertical distribution of archaeal community in the sediment of Zhushan Bay of Lake Taihu, where the black bloom frequently occurred in summer. Overall, the Miscellaneous Crenarchaeotal Group (MCG), Deep Sea Hydrothermal Vent Group 6 (DHVEG-6), and Methanobacterium dominated the archaeal community. However, we observed significant difference in composition of archaeal community among different depths of the sediment. DHVEG-6 dominated in the surface layer (0–3 cm) sediment. Methanobacterium was the dominating archaeal taxa in the L2 (3–6 cm) and L3 (6–10) sediment. MCG was most abundant in the L4 (10–15 cm) and L5 (15–20 cm) sediment. Besides, DHVEG-6 was significantly affected by the concentration of total phosphorus (TP). And loss on ignition (LOI) was an important environmental factor for Methanobacterium. As the typical archaeal taxa in the surface layer sediment, DHVEG-6 and Methanobacterium might be more adapted to abundant substrate supply from cyanobacterial blooms and take active part in the biomass transformation. We propose that DHVEG-6 and Methanobacterium could be the key archaeal taxa correlated with the “black bloom” formation in Zhushan Bay. PMID:26884723

Introduction: The Black Sea as region and horizon

DEFF Research Database (Denmark)

Humphrey, Caroline; Skvirskaja, Vera

2014-01-01

The introduction first outlines different perspectives on the Black Sea: in history, as a site of imperial conflicts and a buffer zone; in area studies, as a “region”; and in anthropology, as a sea crisscrossed by migration, cultural influences, alternative visions, and often a mutual turning...... brought about by migration and trade. In the concluding section we discuss how the Black Sea has appeared as a “horizon” and imaginary of the beyond for the peoples living around its shores....

Contribution of mesoscale eddies to Black Sea ventilation

Science.gov (United States)

Capet, Arthur; Mason, Evan; Pascual, Ananda; Grégoire, Marilaure

2017-04-01

The shoaling of the Black Sea oxycline is one of the most urgent environmental issues in the Black Sea. The permanent oxycline derives directly from the Black Sea permanent stratification and has shoaled alarmingly in the last decades, due to a shifting balance between oxygen consumption and ventilation processes (Capet et al. 2016). The understanding of this balance is thus of the utmost importance and requires to quantify 1) the export of nutrients and organic materials from the shelf regions to the open sea and 2) the ventilation processes. These two processes being influenced by mesoscale features, it is critical to understand the role of the semi-permanent mesoscale structures in horizontal (center/periphery) and vertical (diapycnal and isopycnal) exchanges. A useful insight can be obtained by merging observations from satellite altimeter and in situ profilers (ARGO). In such composite analyses, eddies are first automatically identified and tracked from altimeter data (Mason et al. 2014, py-eddy-tracker). Vertical ARGO profiles are then expressed in terms of their position relative to eddy centers and radii. Derived statistics indicate how consistently mesoscale eddies alter the vertical structure, and provide a deeper understanding of the associated horizontal and vertical fluxes. However, this data-based approach is limited in the Black Sea due to the lower quality of gridded altimetric products in the vicinity of the coast, where semi-permanent mesoscale structures prevail. To complement the difficult analysis of this sparse dataset, a compositing methodology. is also applied to model outputs from the 5km GHER-BHAMBI Black Sea implementation (CMEMS BS-MFC). Characteristic biogeochemical anomalies associated with eddies in the model are analyzed per se, and compared to the observation-based analysis. Capet, A., Stanev, E. V., Beckers, J.-M., Murray, J. W., and Grégoire, M.: Decline of the Black Sea oxygen inventory, Biogeosciences, 13, 1287-1297, doi:10

Mangrove sedimentation and response to relative sea-level rise

Science.gov (United States)

Woodroffe, CD; Rogers, K.; Mckee, Karen L.; Lovelock, CE; Mendelssohn, IA; Saintilan, N.

2016-01-01

Mangroves occur on upper intertidal shorelines in the tropics and subtropics. Complex hydrodynamic and salinity conditions influence mangrove distributions, primarily related to elevation and hydroperiod; this review considers how these adjust through time. Accumulation rates of allochthonous and autochthonous sediment, both inorganic and organic, vary between and within different settings. Abundant terrigenous sediment can form dynamic mudbanks; tides redistribute sediment, contrasting with mangrove peat in sediment-starved carbonate settings. Sediments underlying mangroves sequester carbon, but also contain paleoenvironmental records of adjustments to past sea-level changes. Radiometric dating indicates long-term sedimentation, whereas Surface Elevation Table-Marker Horizon measurements (SET-MH) provide shorter perspectives, indicating shallow subsurface processes of root growth and substrate autocompaction. Many tropical deltas also experience deep subsidence, which augments relative sea-level rise. The persistence of mangroves implies an ability to cope with moderately high rates of relative sea-level rise. However, many human pressures threaten mangroves, resulting in continuing decline in their extent throughout the tropics.

Mangrove Sedimentation and Response to Relative Sea-Level Rise.

Science.gov (United States)

Woodroffe, C D; Rogers, K; McKee, K L; Lovelock, C E; Mendelssohn, I A; Saintilan, N

2016-01-01

Mangroves occur on upper intertidal shorelines in the tropics and subtropics. Complex hydrodynamic and salinity conditions, related primarily to elevation and hydroperiod, influence mangrove distributions; this review considers how these distributions change over time. Accumulation rates of allochthonous and autochthonous sediment, both inorganic and organic, vary between and within different settings. Abundant terrigenous sediment can form dynamic mudbanks, and tides redistribute sediment, contrasting with mangrove peat in sediment-starved carbonate settings. Sediments underlying mangroves sequester carbon but also contain paleoenvironmental records of adjustments to past sea-level changes. Radiometric dating indicates long-term sedimentation, whereas measurements made using surface elevation tables and marker horizons provide shorter perspectives, indicating shallow subsurface processes of root growth and substrate autocompaction. Many tropical deltas also experience deep subsidence, which augments relative sea-level rise. The persistence of mangroves implies an ability to cope with moderately high rates of relative sea-level rise. However, many human pressures threaten mangroves, resulting in a continuing decline in their extent throughout the tropics.

3D multidisciplinary numerical model of polychlorinated biphenyl dynamics on the Black Sea north-western shelf

Science.gov (United States)

Bagaiev, Andrii; Ivanov, Vitaliy

2014-05-01

The Black Sea north-western shelf plays a key role in economics of the developing countries such as Ukraine due to food supply, invaluable recreational potential and variety of the relevant maritime shipping routes. On the other hand, a shallow flat shelf is mostly affected by anthropogenic pollution, eutrophication, hypoxia and harmful algae blooms. The research is focused on modeling the transport and transformation of PCBs (PolyChlorinated Biphenyls) because they are exceedingly toxic and highly resistant to degradation, hence cumulatively affect marine ecosystems. Being lipophilic compounds, PCBs demonstrate the distinguishing sorption/desorption activity taking part in the biogeochemical fluxes via the organic matter particles and sediments. In the framework of the research, the coastal in-situ data on PCB concentration in the water column and sediments are processed, visualized and analyzed. It is concluded that the main sources of PCBs are related to the Danube discharge and resuspension from the shallow-water sediments. Developed 3D numerical model is aimed at simulation of PCB contamination of the water column and sediment. The model integrates the full physics hydrodynamic block as well as modules, which describe detritus transport and transformation and PCB dynamics. Three state variables are simulated in PCB transport module: concentration in solute, on the settling particles of detritus and in the top layer of sediments. PCB adsorption/desorption on detritus; the reversible PCB fluxes at the water-sediment boundary; destruction of detritus are taken into consideration. Formalization of PCB deposition/resuspension in the sediments is adapted from Van Rijn's model of the suspended sediment transport. The model was spun up to reconstruct the short term scenario of the instantaneous PCB release from the St. George Arm of Danube. It has been shown that PCB transport on sinking detritus represents the natural buffer mechanism damping the spreading PCB

Small river plumes off the northeastern coast of the Black Sea under average climatic and flooding discharge conditions

Science.gov (United States)

Osadchiev, Alexander; Korshenko, Evgeniya

2017-06-01

This study focuses on the impact of discharges of small rivers on the delivery and fate of fluvial water and suspended matter at the northeastern part of the Black Sea under different local precipitation conditions. Several dozens of mountainous rivers flow into the sea at the study region, and most of them, except for several of the largest, have little annual runoff and affect adjacent coastal waters to a limited extent under average climatic conditions. However, the discharges of these small rivers are characterized by a quick response to precipitation events and can significantly increase during and shortly after heavy rains, which are frequent in the considered area. The delivery and fate of fluvial water and terrigenous sediments at the study region, under average climatic and rain-induced flooding conditions, were explored and compared using in situ data, satellite imagery, and numerical modeling. It was shown that the point-source spread of continental discharge dominated by several large rivers under average climatic conditions can change to the line-source discharge from numerous small rivers situated along the coast in response to heavy rains. The intense line-source runoff of water and suspended sediments forms a geostrophic alongshore current of turbid and freshened water, which induces the intense transport of suspended and dissolved constituents discharged with river waters in a northwestern direction. This process significantly influences water quality and causes active sediment load at large segments of the narrow shelf at the northeastern part of the Black Sea compared to average climatic discharge conditions.

Small river plumes off the northeastern coast of the Black Sea under average climatic and flooding discharge conditions

Directory of Open Access Journals (Sweden)

A. Osadchiev

2017-06-01

Full Text Available This study focuses on the impact of discharges of small rivers on the delivery and fate of fluvial water and suspended matter at the northeastern part of the Black Sea under different local precipitation conditions. Several dozens of mountainous rivers flow into the sea at the study region, and most of them, except for several of the largest, have little annual runoff and affect adjacent coastal waters to a limited extent under average climatic conditions. However, the discharges of these small rivers are characterized by a quick response to precipitation events and can significantly increase during and shortly after heavy rains, which are frequent in the considered area. The delivery and fate of fluvial water and terrigenous sediments at the study region, under average climatic and rain-induced flooding conditions, were explored and compared using in situ data, satellite imagery, and numerical modeling. It was shown that the point-source spread of continental discharge dominated by several large rivers under average climatic conditions can change to the line-source discharge from numerous small rivers situated along the coast in response to heavy rains. The intense line-source runoff of water and suspended sediments forms a geostrophic alongshore current of turbid and freshened water, which induces the intense transport of suspended and dissolved constituents discharged with river waters in a northwestern direction. This process significantly influences water quality and causes active sediment load at large segments of the narrow shelf at the northeastern part of the Black Sea compared to average climatic discharge conditions.

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

Recent Extreme Marine Events at Southern Coast of Black Sea

Science.gov (United States)

Ozyurt Tarakcioglu, Gulizar; Cevdet Yalciner, Ahmet; Kirezci, Cagil; Baykal, Cuneyt; Gokhan Guler, Hasan; Erol, Onur; Zaytsev, Andrey; Kurkin, Andrey

2015-04-01

The utilization at the coastal areas of Black Sea basin has increased in the recent years with the projects such as large commercial ports, international transportation hubs, gas and petrol pipelines, touristic and recreational infrastructures both along surrounding shoreline. Although Black Sea is a closed basin, extreme storms and storm surges have also been observed with an increasing frequency in the recent years. Among those events, February 1999, March 2013 and September 2014 storms impacted Southern coast of Black sea have clearly shown that the increasing economic value at the coastal areas caused the increasing cost of damages and loss of property by natural hazards. The storm occurred on February 19-20, 1999 is one of the most destructive storm in the last decades. The 1999 event (1999 Southern Black sea storm) caused destruction at all harbors and coastal protection structures along the Black Sea coast of Turkey. The complete damage of the breakwater of Giresun Harbor and damage on the harbor structures and cargo handling equipment were the major impacts of the 1999 Southern Black sea storm. Similar coastal impact have also been observed during the September 24, 2014 storm at 500m East of Giresun harbor. Although there are considerable number of destructive storms observed at southern coast of Black sea recently, data on these events are limited and vastly scattered. In this study the list of recent extreme marine events at South coast of the Black sea compiled and related data such as wind speed, wave height, period, and type of damages are cataloged. Particular attention is focused on the 1999 and 2014 storm events. The meteorological and morphological characteristics which may be considered as the reasons of the generation and coastal amplification of these storms are discussed. ACKNOWLEDGEMENTS: This study is partly supported by Turkish Russian Joint Research Grant Program by TUBITAK (Turkey) and RFBR (Russia), and TUBITAK 213M534 Research Project.

Sorption of americium and neptunium by deep-sea sediments

International Nuclear Information System (INIS)

Higgo, J.J.W.; Rees, L.V.C.; Cronan, D.S.

1983-01-01

The sorption and desorption of americium and neptunium by a wide range of deep-sea sediments from natural sea water at 4 0 C has been studied using a carefully controlled batch technique. All the sediments studied should form an excellent barrier to the migration of americium since distribution coefficients were uniformly greater than 10 5 and the sorption-desorption reaction may not be reversible. The sorption of neptunium was reversible and, except for one red clay, the distribution coefficients were greater than 10 3 for all the sediments investigated. Nevertheless the migration of neptunium should also be effectively retarded by most deep-sea sediments even under relatively oxidizing conditions. The neptunium in solution remained in the V oxidation state throughout the experiments. Under the experimental conditions used colloidal americium was trapped by the sediment and solubility did not seem to be the controlling factor in the desorption of americium. (Auth.)

Sediment volume in the north polar sand seas of Mars

International Nuclear Information System (INIS)

Lancaster, N.; Greeley, R.

1990-01-01

Data from studies of the cross-sectional area of terrestrial transverse dunes have been combined with maps of dune morphometry derived from Viking orbiter images to generate new estimates of sediment thickness and dune sediment volume in the north polar sand seas of Mars. A relationship between dune spacing and equivalent sediment thickness (EST) was developed from field data on Namibian and North American dunes and was applied to data on dune spacing and dune cover measured on Viking orbiter images to generate maps of dune sediment thickness for Martian north polar sand seas. There are four major sand seas in the north polar region of Mars, covering an area of 6.8 x 10 5 km 2 . Equivalent sediment thickness ranges between 0.5 and 6.1 m with a mean of 1.8 m. The sand seas contain a total of 1158 km 3 of dune sediment, which may have been derived by erosion of polar layered deposits and concentrated in its present location by winds that change direction seasonally

Contemporary genetic structure and postglacial demographic history of the black scorpionfish, Scorpaena porcus, in the Mediterranean and the Black Seas.

Science.gov (United States)

Boissin, E; Micu, D; Janczyszyn-Le Goff, M; Neglia, V; Bat, L; Todorova, V; Panayotova, M; Kruschel, C; Macic, V; Milchakova, N; Keskin, Ç; Anastasopoulou, A; Nasto, I; Zane, L; Planes, S

2016-05-01

Understanding the distribution of genetic diversity in the light of past demographic events linked with climatic shifts will help to forecast evolutionary trajectories of ecosystems within the current context of climate change. In this study, mitochondrial sequences and microsatellite loci were analysed using traditional population genetic approaches together with Bayesian dating and the more recent approximate Bayesian computation scenario testing. The genetic structure and demographic history of a commercial fish, the black scorpionfish, Scorpaena porcus, was investigated throughout the Mediterranean and Black Seas. The results suggest that the species recently underwent population expansions, in both seas, likely concomitant with the warming period following the Last Glacial Maximum, 20 000 years ago. A weak contemporaneous genetic differentiation was identified between the Black Sea and the Mediterranean Sea. However, the genetic diversity was similar for populations of the two seas, suggesting a high number of colonizers entered the Black Sea during the interglacial period and/or the presence of a refugial population in the Black Sea during the glacial period. Finally, within seas, an east/west genetic differentiation in the Adriatic seems to prevail, whereas the Black Sea does not show any structured spatial genetic pattern of its population. Overall, these results suggest that the Black Sea is not that isolated from the Mediterranean, and both seas revealed similar evolutionary patterns related to climate change and changes in sea level. © 2016 John Wiley & Sons Ltd.

A greigite-based magnetostratigraphic time frame for the Late Miocene to Recent DSDP Leg 42B cores from the Black Sea

Directory of Open Access Journals (Sweden)

Christiaan Gijsbert Cornelis Van Baak

2016-05-01

Full Text Available Throughout the Late Neogene, the Black Sea experienced large paleoenvironmental changes, switching between (anoxic marine conditions when connected to the Mediterranean Sea and (oxic freshwater conditions at times of isolation. We create a magnetostratigraphic time frame for three sites drilled during Deep Sea Drilling Project (DSDP Leg 42B to the Black Sea (drilled in 1975. At the time, magnetostratigraphic dating was impossible because of the presence of the little understood iron sulfide mineral greigite (in sediments a precursor to pyrite as magnetic carrier. Our rock-magnetic results indicate that only anoxic conditions result in poor magnetic signal, likely as a result of pyrite formation in the water column rather than in the sediment. The magnetostratigraphic results indicate that Hole 379A, drilled in the basin center, has a continuous sedimentary record dating back to 1.3 Ma. Hole 380/380A is subdivided into three consistent intervals, 0-700 mbsf, 700-860 mbsf and 860-1075 mbsf. The top unit covers the Pleistocene but the magnetostratigraphy is likely compromised by the presence of mass transport deposits. The middle unit spans between 4.3 and 6.1 Ma and records continuous deposition at ~10 cm/kyr. The lower unit lacks the independent age constraints to correlate the obtained magnetostratigraphy. Hole 381 is drilled on the Bosporus slope and as a result, hiatuses are common. A correlation to the nearby Hole 380/380A is proposed, but indicates deposits cannot straightforwardly be traced across the slope. Our improved age model does not support the original interpretation based on these cores of a desiccation of the Black Sea during the Messinian salinity crisis.

Seasonal hypoxia in eutrophic stratified coastal shelves: mechanisms, sensibilities and interannual variability from the North-Western Black Sea case

Science.gov (United States)

Capet, A.; Beckers, J.-M.; Grégoire, M.

2012-12-01

The Black Sea north-western shelf (NWS) is a~shallow eutrophic area in which seasonal stratification of the water column isolates bottom waters from the atmosphere and prevents ventilation to compensate for the large consumption of oxygen, due to respiration in the bottom waters and in the sediments. A 3-D coupled physical biogeochemical model is used to investigate the dynamics of bottom hypoxia in the Black Sea NWS at different temporal scales from seasonal to interannual (1981-2009) and to differentiate the driving factors (climatic versus eutrophication) of hypoxic conditions in bottom waters. Model skills are evaluated by comparison with 14 500 in-situ oxygen measurements available in the NOAA World Ocean Database and the Black Sea Commission data. The choice of skill metrics and data subselections orientate the validation procedure towards specific aspects of the oxygen dynamics, and prove the model's ability to resolve the seasonal cycle and interannual variability of oxygen concentration as well as the spatial location of the oxygen depleted waters and the specific threshold of hypoxia. During the period 1981-2009, each year exhibits seasonal bottom hypoxia at the end of summer. This phenomenon essentially covers the northern part of the NWS, receiving large inputs of nutrients from the Danube, Dniestr and Dniepr rivers, and extends, during the years of severe hypoxia, towards the Romanian Bay of Constanta. In order to explain the interannual variability of bottom hypoxia and to disentangle its drivers, a statistical model (multiple linear regression) is proposed using the long time series of model results as input variables. This statistical model gives a general relationship that links the intensity of hypoxia to eutrophication and climate related variables. The use of four predictors allows to reproduce 78% of hypoxia interannual variability: the annual nitrate discharge (N), the sea surface temperature in the month preceding stratification (T), the

Fungi and macroaggregation in deep-sea sediments

Digital Repository Service at National Institute of Oceanography (India)

Damare, S.R.; Raghukumar, C.

Whereas fungi in terrestrial soils have been well studied, little is known of them in deep-sea sediments. Recent studies have demonstrated the presence of fungal hyphae in such sediments but in low abundance. We present evidence in this study...

Real-time PCR quantification and diversity analysis of the functional genes aprA and dsrA of sulfate-reducing bacteria in marine sediments of the Peru continental margin and the Black Sea

OpenAIRE

Axel eSchippers; Anna eBlazejak

2011-01-01

A quantitative, real-time PCR (Q-PCR) assay for the functional gene adenosine 5´-phosphosulfate reductase (aprA) of sulfate-reducing bacteria (SRB) was designed. This assay was applied together with described Q-PCR assays for dissimilatory sulfite reductase (dsrA) and the 16S rRNA gene of total Bacteria to marine sediments from the Peru margin (0 – 121 meters below seafloor (mbsf)) and the Black Sea (0 – 6 mbsf). Clone libraries of aprA show that all isolated sequences originate from SRB...

Quo vadis NW Black Sea benthic ecosystems?

Science.gov (United States)

Traian Gomoiu, Marian

2016-04-01

The author briefly presents a general review on the evolution trends of benthic ecosystems at the Romanian Black Sea coast, referring to some recent data from the literature. The Black Sea represents a "unicum hydrobiologicum" by some of its basic characteristics, such as: 1. a large semi-enclosed basin with an intense exchange of waters; 2. a sea receiving a large amount of fresh water, especially in its northwestern sector, brought by the Danube, Dnieper and Dniester Rivers; 3. a large meromictic sea - euxinic-azoic below depths of 150 - 200 m; 4. around the sea there is a large filter-holding belt consisting of bivalves (Mytilus galloprovincialis and Modiolula phaseolina); 5. a sea having in its northwestern sector a large area covered by red algae of the genus Phyllophora; 6. a sea undergoing, in the last 50 years, intense environmental pressures (pollution by large rivers and direct discharges of wastewater from urban areas, the development of maritime traffic, overfishing by bottom trawling, coastal facilities and especially by many defense works of the new port); 7. a sea registering in the last decades of the past century many events of eutrophication; 8. a sea enriching its biodiversity by alien species. After the political and socio-economic changes triggered by the events of 1989 and especially after Romania's accession to EU, the state of the northwestern Black Sea coastal ecosystems, has recorded positive changes: • Decrease in environmental pressures; • Decreasing pollutant / fertilizing discharges into the Danube; • Reduction of domestic sewage quantities from coastal settlements; • Improvement in the quality of the wastewater discharged into the sea; • Reduction of active fishing by bottom trawling; • Adopting and implementing a national / international set of guidelines concerning marine environment; • Adopting regulations on the protection of the marine environment against pollution in marine economy: transport / shipping, tourism

The effects of additional black carbon on Arctic sea ice surface albedo: variation with sea ice type and snow cover

OpenAIRE

A. A. Marks; M. D. King

2013-01-01

Black carbon in sea ice will decrease sea ice surface albedo through increased absorption of incident solar radiation, exacerbating sea ice melting. Previous literature has reported different albedo responses to additions of black carbon in sea ice and has not considered how a snow cover may mitigate the effect of black carbon in sea ice. Sea ice is predominately snow covered. Visible light absorption and light scattering coefficients are calculated for a typical first year and multi-y...

Sound-scattering layers of the Black Sea based on ADCP observations

Science.gov (United States)

Morozov, A. N.; Lemeshko, E. M.; Fedorov, S. V.

2017-09-01

The paper discusses the results of expeditions to the northwestern part of the Black Sea carried out in 2004-2008. Acoustic Doppler Current Profilers (ADCP) with an operating frequency of 150 and 300 kHz were used as the echo sounders. The characteristic scales of the spatial variability of sound scattering in the Black Sea were determined; the revealed peculiarities are interpreted. The characteristics of a deep soundscattering layer in the Black Sea are given.

The effects of additional black carbon on the albedo of Arctic sea ice: variation with sea ice type and snow cover

Directory of Open Access Journals (Sweden)

A. A. Marks

2013-07-01

Full Text Available The response of the albedo of bare sea ice and snow-covered sea ice to the addition of black carbon is calculated. Visible light absorption and light-scattering cross-sections are derived for a typical first-year and multi-year sea ice with both "dry" and "wet" snow types. The cross-sections are derived using data from a 1970s field study that recorded both reflectivity and light penetration in Arctic sea ice and snow overlying sea ice. The variation of absorption cross-section over the visible wavelengths suggests black carbon is the dominating light-absorbing impurity. The response of first-year and multi-year sea ice albedo to increasing black carbon, from 1 to 1024 ng g−1, in a top 5 cm layer of a 155 cm-thick sea ice was calculated using a radiative-transfer model. The albedo of the first-year sea ice is more sensitive to additional loadings of black carbon than the multi-year sea ice. An addition of 8 ng g−1 of black carbon causes a decrease to 98.7% of the original albedo for first-year sea ice compared to a decrease to 99.7% for the albedo of multi-year sea ice, at a wavelength of 500 nm. The albedo of sea ice is surprisingly unresponsive to additional black carbon up to 100 ng g−1 . Snow layers on sea ice may mitigate the effects of black carbon in sea ice. Wet and dry snow layers of 0.5, 1, 2, 5 and 10 cm depth were added onto the sea ice surface. The albedo of the snow surface was calculated whilst the black carbon in the underlying sea ice was increased. A layer of snow 0.5 cm thick greatly diminishes the effect of black carbon in sea ice on the surface albedo. The albedo of a 2–5 cm snow layer (less than the e-folding depth of snow is still influenced by the underlying sea ice, but the effect of additional black carbon in the sea ice is masked.

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.

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

A study of the anthropic activities impact on the Black Sea eco-system (Romanian coast area) using nuclear methods

International Nuclear Information System (INIS)

Timofte, L.

1997-01-01

This research represents a first step in the direction of a real evaluation of the Black Sea - Romanian Coast pollution level. A continental closed sea, with a special chemism and a specific dynamic regime of its waters, the Black Sea is seriously affected by pollution today, its eco - systems suffering deep restructuring, many of these with an irreversible character and an alarming degradation of the marine life quality. Starting with 1996, a systematic sampling of the principal systemic parts of the Black Sea Eco - System (Romanian Coast Area) was initiated at NIPNE - HH Bucharest. The samples are prepared and analysed by high precision nuclear methods such as: neutron activation analysis, atomic absorption spectrometry, inductively coupled plasma mass spectrometry and others. The results are presented as distribution maps and profiles of different elements (radioactive elements, heavy metals, trace elements etc.) in the investigated parts of the marine environment (water, sediments, vegetation and fauna). The research methodology and the obtained results offer a useful and efficient tool for the followup and permanent evaluation of the eco - system of the Black Sea. Monitoring this eco - system using a network and an efficient programme allows the storage of valuable data which are further used to make short - term and long - term prognosis referring to its evaluation. The results fit into the newest research programmes initiated by the international scientific community in the line of environment surveillance (The Programme of the International Board for Scientific Exploration of the Mediterranean supported by the European Community and US). (author)

Distribution of organic carbon in surface sediments along the eastern Arabian Sea: a revisit

Digital Repository Service at National Institute of Oceanography (India)

PrakashBabu, C.; Brumsack, H.-J.; Schnetger, B.

, 1990; Paropkari et al., 1992, 1993a,b; Calvert et al., . 1995 . OC enrichments of )8% with maxima of up ) Corresponding author. Fax: q49-441-798-3404; E-mail: brumsack@icbm.de 1 E-mail: pbabu@csnio.ren.nic.in, pbabu@darya.nio.org. 2 E-mail: schnetger@icbm.de... sediments, that are too high by up to a factor of two. Weliky et al. . 1983 already pointed out that problems are evident when OC determinations are performed exclusively by the wet oxidation method. . Our analyses of Holocene Black Sea sapropels...

Variational data assimilation system "INM RAS - Black Sea"

Science.gov (United States)

Parmuzin, Eugene; Agoshkov, Valery; Assovskiy, Maksim; Giniatulin, Sergey; Zakharova, Natalia; Kuimov, Grigory; Fomin, Vladimir

2013-04-01

Development of Informational-Computational Systems (ICS) for Data Assimilation Procedures is one of multidisciplinary problems. To study and solve these problems one needs to apply modern results from different disciplines and recent developments in: mathematical modeling; theory of adjoint equations and optimal control; inverse problems; numerical methods theory; numerical algebra and scientific computing. The problems discussed above are studied in the Institute of Numerical Mathematics of the Russian Academy of Science (INM RAS) in ICS for Personal Computers (PC). Special problems and questions arise while effective ICS versions for PC are being developed. These problems and questions can be solved with applying modern methods of numerical mathematics and by solving "parallelism problem" using OpenMP technology and special linear algebra packages. In this work the results on the ICS development for PC-ICS "INM RAS - Black Sea" are presented. In the work the following problems and questions are discussed: practical problems that can be studied by ICS; parallelism problems and their solutions with applying of OpenMP technology and the linear algebra packages used in ICS "INM - Black Sea"; Interface of ICS. The results of ICS "INM RAS - Black Sea" testing are presented. Efficiency of technologies and methods applied are discussed. The work was supported by RFBR, grants No. 13-01-00753, 13-05-00715 and by The Ministry of education and science of Russian Federation, project 8291, project 11.519.11.1005 References: [1] V.I. Agoshkov, M.V. Assovskii, S.A. Lebedev, Numerical simulation of Black Sea hydrothermodynamics taking into account tide-forming forces. Russ. J. Numer. Anal. Math. Modelling (2012) 27, No.1, 5-31 [2] E.I. Parmuzin, V.I. Agoshkov, Numerical solution of the variational assimilation problem for sea surface temperature in the model of the Black Sea dynamics. Russ. J. Numer. Anal. Math. Modelling (2012) 27, No.1, 69-94 [3] V.B. Zalesny, N.A. Diansky, V

Sediment pore water distribution coefficients of PCB congeners in enriched black carbon sediment

International Nuclear Information System (INIS)

Martinez, Andres; O'Sullivan, Colin; Reible, Danny; Hornbuckle, Keri C.

2013-01-01

More than 2300 sediment pore water distribution coefficients (K PCBids ) of 93 polychlorinated biphenyls (PCBs) were measured and modeled from sediments from Indiana Harbor and Ship Canal. K PCBids were calculated from previously reported bulk sediment values and newly analyzed pore water. PCBs in pore waters were measured using SPME PDMS-fiber and ∑PCB ranged from 41 to 1500 ng L −1 . The resulting K PCBids were ∼1 log unit lower in comparison to other reported values. A simple model for the K PCBid consisted of the product of the organic carbon fraction and the octanol–water partition coefficient and provided an excellent prediction for the measured values, with a mean square error of 0.09 ± 0.06. Although black carbon content is very high in these sediments and was expected to play an important role in the distribution of PCBs, no improvement was obtained when a two-carbon model was used. -- Highlights: •PCB sediment-pore water distribution coefficients were measured and modeled. •Distribution coefficients were lower in comparison to other reported values. •Organic carbon fraction times the K OW yielded the best prediction model. •The incorporation of black carbon into a model did not improve the results. -- The organic carbon fraction times the octanol–water partition coefficient yielded the best prediction model for the sediment pore water distribution coefficient of PCBs

A Moessbauer study of deep sea sediments

International Nuclear Information System (INIS)

Minai, Y.; Tominaga, T.; Furuta, T.; Kobayashi, K.

1981-01-01

In order to determine the chemical states of iron in deep sea sediments, Moessbauer spectra of the sediments collected from various areas of the Pacific have been measured. The Moessbauer spectra were composed of paramagnetic ferric, high-spin ferrous, and magnetic components. The correlation of their relative abundance to the sampling location and the kind of sediments may afford clues to infer the origin of each iron-bearing phase. (author)

Neogene sedimentation on the outer continental margin, southern Bering Sea

Science.gov (United States)

Vallier, T.L.; Underwood, M.B.; Gardner, J.V.; Barron, J.A.

1980-01-01

Neogene sedimentary rocks and sediments from sites on the outer continental margin in the southern Bering Sea and on the Alaska Peninsula are dominated by volcanic components that probably were eroded from an emergent Aleutian Ridge. A mainland continental source is subordinate. Most sediment in the marine environment was transported to the depositional sites by longshore currents, debris flows, and turbidity currents during times when sea level was near the outermost continental shelf. Fluctuations of sea level are ascribed both to worldwide glacio-eustatic effects and to regional vertical tectonics. Large drainage systems, such as the Yukon and Kuskokwim Rivers, had little direct influence on sedimentation along the continental slope and Unmak Plateau in the southern Bering Sea. Sediments from those drainage systems probably were transported to the floor of the Aleutian Basin, to the numerous shelf basins that underlie the outer continental shelf, and to the Arctic Ocean after passing through the Bering Strait. Environments of deposition at the sites along the outer continental margin have not changed significantly since the middle Miocene. The site on the Alaska Peninsula, however, is now emergent following shallow-marine and transitional sedimentation during the Neogene. ?? 1980.

Wind impact on the Black Sea ecosystem

Science.gov (United States)

Stanichny, Sergey; Ratner, Yuriy; Shokurov, Mike; Stanychna, Rimma; Soloviev, Dmytro; Burdyugov, Vyacheslav

2010-05-01

Combination of the recent satellite and meteorological data for the regional investigation allowed to describe new features of the processes in marine ecosystem and detect some relations with wind variability for different time scales. Next topics are highlighted in presentation: 1. Inter-annual variability of the wind stress curl over the Black Sea. Shift in the atmospheric processes after 2003 year and related variations in chlorophyll concentration and intensity of the mesoscale currents. 2. Like-tropical cyclone in September 2005 and its impact o the Black Sea upper layer. 3. Strong storm November 11, 2007 and oil pollutions of the Kerch Strait. 4. Relation of the Danube waters transport with wind fields for summer 2007 and 2008. 5. "Valley" wind in the Eastern part of the Black Sea and its impact on the Rim current formation. 6. Low wind conditions and blue -green algae bloom. NCEP, SKIRON and MHI MM5 wind data together with AVHRR, MODIS, MERIS, ETM+, QuikSCAT, ASAR (ESA) satellite data were used for investigation. Work was done with support of the SESAME FP7, "Stable Ecosystem" and Operational Oceanography NASU projects.

Tides in three enclosed basins: the Baltic, Black and Caspian seas

Directory of Open Access Journals (Sweden)

Igor P Medvedev

2016-04-01

Full Text Available Tides are the main type of sea level variability in the world ocean. However, oceanic tides penetrate weakly, or do not penetrate at all, into enclosed basins such as the Baltic, Black and Caspian seas. Consequently, only directly forced tides are formed in these basins. Long observation time series (up to 123 years in the Baltic Sea and 38 years in the Black and Caspian seas at numerous stations were used to precisely estimate tidal constituents. High-resolution spectra revealed fine structure of discrete peaks at tidal frequencies. The diurnal radiational constituent S1 (1 cpd, apparently associated with breeze winds, was found to play an important role in general tidal dynamics in these seas. Harmonic analysis of tides for individual yearly series with consecutive vector averaging over the entire observational period was applied to estimate mean amplitudes and phases of tidal constituents. Our findings indicate that the formation and predominance of diurnal or semidiurnal tides in these seas appears to depend on the frequency-selective properties of the basins. Thus, in the Baltic Sea with fundamental modal period of about 27 h, diurnal tides dominate in the major eastern gulfs. In the Black Sea resonant amplification of semidiurnal tides is observed in the northwestern part. The predominance of semidiurnal tides in the Caspian Sea has also probably a resonant nature. Maximum tidal heights estimated for a 100-year period are 23 cm in the Baltic Sea, 18 cm in the Black Sea and 21 cm in the southern Caspian Sea.

Diversity, abundance and distribution of amoA-encoding archaea in deep-sea methane seep sediments of the Okhotsk Sea.

Science.gov (United States)

Dang, Hongyue; Luan, Xi-Wu; Chen, Ruipeng; Zhang, Xiaoxia; Guo, Lizhong; Klotz, Martin G

2010-06-01

The ecological characteristics of amoA-encoding archaea (AEA) in deep-sea sediments are largely unsolved. This paper aimed to study the diversity, structure, distribution and abundance of the archaeal community and especially its AEA components in the cold seep surface sediments of the Okhotsk Sea, a marginal sea harboring one of the largest methane hydrate reservoirs in the world. Diverse archaeal 16S rRNA gene sequences were identified, with the majority being related to sequences from other cold seep and methane-rich sediment environments. However, the AEA diversity and abundance were quite low as revealed by amoA gene analyses. Correlation analysis indicates that the abundance of the archaeal amoA genes was correlated with the sediment organic matter content. Thus, it is possible that the amoA-carrying archaea here might utilize organic matter for a living. The affiliation of certain archaeal amoA sequences to the GenBank sequences originally obtained from deep-sea hydrothermal vent environments indicated that the related AEA either have a wide range of temperature adaptation or they have a thermophilic evolutionary history in the modern cold deep-sea sediments of the Okhotsk Sea. The dominance of ammonia-oxidizing bacteria over AEA may indicate that bacteria play a significant role in nitrification in the Okhotsk Sea cold seep sediments.

Petroleum hydrocarbon contamination of the Southern Black Sea Shelf, Turkey.

Science.gov (United States)

Balkıs, Nuray; Aksu, Abdullah; Erşan, Mahmut S

2012-02-01

In this study, total petroleum hydrocarbon (TPH) contents and some aliphatic and aromatic hydrocarbon concentrations were analysed in coastal sediments of hot points collected from along the Southern Black Sea Shelf. Surface sediment (0-2 cm) samples were collected from the locations using a Van Veen type grab sampler in September 2008 during a cruise on the Pollution Monitoring R/V ARAR. All sampling procedures were carried out according to internationally recognized guide-lines (UNEP 1991). Samples were analysed using a UV-fluorescence spec-trophotometry (UNEP/IOC/IAEA 1992) and gas chromatog- raphy (GC) via a Hewlett-Packard HP6890N series with a selective detector (GC-MSD) after hexane/ dichloromethane extraction. The ratio C(17)/C(18) varied between 2.2 and 2.9 for the surface sediments of TRK 34Y (Samsun), TRK46 (Giresun), and TRK55 (Rize), respectively. These results showed higher marine organic matter accumulation. However, pyrolytic PAHs were found predominant in these areas. In contrast, petrogenic contributions were found at Stations TRK1 (İğneada), TRK13 (Zonguldak), TRK53 (Trabzon) and TRK61 (Hopa). TPH contents of surface sediments varied between 0.29 and 363 μg g(-1) (dry wt) throughout the shelf. The lowest values were measured at Stations TRK1 (İğneada) and TRK 19 (Bartın), whereas the highest values were found at Stations TRK13 (Zonguldak) and TRK 53 (Trabzon).

Black Sea GIS developed in MHI

Science.gov (United States)

Zhuk, E.; Khaliulin, A.; Zodiatis, G.; Nikolaidis, A.; Isaeva, E.

2016-08-01

The work aims at creating the Black Sea geoinformation system (GIS) and complementing it with a model bank. The software for data access and visualization was developed using client server architecture. A map service based on MapServer and MySQL data management system were chosen for the Black Sea GIS. Php-modules and python-scripts are used to provide data access, processing, and exchange between the client application and the server. According to the basic data types, the module structure of GIS was developed. Each type of data is matched to a module which allows selection and visualization of the data. At present, a GIS complement with a model bank (the models build in to the GIS) and users' models (programs launched on users' PCs but receiving and displaying data via GIS) is developed.

Sea level change along the Black Sea coast from satellite altimetry, tide gauge and GPS observations

Directory of Open Access Journals (Sweden)

Nevin B. Avsar

2016-01-01

Full Text Available Sea level change affects human living conditions, particularly ocean coasts. However, sea level change is still unclear along the Black Sea coast due to lack of in-situ measurements and low resolution satellite data. In this paper, sea level change along the Black Sea coast is investigated from joint satellite altimetry, tide gauge (TG and Global Positioning System (GPS observations. The linear trend and seasonal components of sea level change are estimated at 8 TG stations (Amasra, Igneada, Trabzon-II, Sinop, Sile, Poti, Tuapse, and Batumi located along the Black Sea coast, which are compared with Satellite Altimetry and GPS. At the tide gauge stations with long-term records such as Poti (about 21 years and Tuapse (about 19 years, the results obtained from the satellite altimetry and tide gauge observations show a remarkably good agreement. While some big differences are existed between Satellite Altimetry and TG at other stations, after adding vertical motion from GPS, correlation coefficients of the trend have been greatly improved from 0.37 to 0.99 at 3 co-located GPS and TG stations (Trabzon-II, Sinop and Sile.

Habitat preferences among three top predators inhabiting a degraded ecosystem, the Black Sea

Directory of Open Access Journals (Sweden)

Alicia Sánchez-Cabanes

2017-06-01

Full Text Available This study investigated whether there is evidence of widespread niche partitioning based on environmental factors in the Black Sea and tested the hypothesis that physiographic factors may be employed as predictors. It addresses poorly researched areas with good habitat potential for the only three cetacean subspecies living in this area: the Black Sea short-beaked common dolphin (Delphinus delphis spp. ponticus, the Black Sea bottlenose dolphin (Tursiops truncatus spp. ponticus and the Black Sea harbour porpoise (Phocoena phocoena spp. relicta. Generalized additive models (GAMs were used to analyse data collected from multiple sources. In total, 745 sightings of the three species between 1998 and 2010 throughout the Black Sea were included. The analysis found depth and sea surface temperature to be the most important variables for separating the occurrence of the three species. Common dolphins occurred mainly in deep waters and in areas where the sea surface temperature was low, bottlenose dolphins were distributed primarily in shallower and warmer waters than common dolphins, and harbour porpoises were distributed in shallower waters with lower sea surface temperature than bottlenose dolphins. This study suggests strong niche segregation among the three cetacean species. The study is also the first contribution to the basic information of cetacean species distribution and habitat preferences in the Black Sea as a whole. Knowledge of the distribution of the three dolphin species in the study area is essential to establish conservation measures for these populations.

Radiocarbon dating of Irish Sea sediments

Science.gov (United States)

Kershaw, P. J.

1986-09-01

Radiocarbon dating has been carried out on three cores from areas of muddy sediments in the N. Irish Sea to estimate rates of sediment accumulation. 14C age profiles of the two eastern basin cores revealed a near-constant age from the sediment surface to the base of the core (12 500±1000 years bp). The 14C age profile of the western basin core revealed a zone of apparent mixing to a depth of 55 cm, underlain by a zone of constant sedimentation rate (0·018 cm y -1) to 160 cm. These data are discussed in relation both to previously reported sedimentological studies of the area and to the authorised discharges of low-level radioactive waste from the Sellafield nuclear fuel reprocessing plant.

Spectral partitioning and swells in the black sea

NARCIS (Netherlands)

van Vledder, G.P.; Akpınar, Adem; Lynett, P.

2016-01-01

The swell climate of the Black Sea has been determined using a long-term 31-year wave hindcast with the thirdgeneration spectral wave model SWAN in combination with spectral partitioning. This technique enables decomposing wave spectra into individual wave systems representing wind seas or swells

Radiotracers in the Black Sea: A Tool for Marine Environmental Assessments

Energy Technology Data Exchange (ETDEWEB)

Gulin, S. B.; Egorov, V. N.; Polikarpov, G. G.; Stokozov, N. A.; Mirzoeva, N. Y.; Tereshenko, N. N.; Gulina, L. V.; Proskurnin, V. Y. [A.O. Kovalevskiy Institute of Biology of the Southern Seas (IBSS), Sevastopol (Ukraine); Osvath, I. [International Atomic Energy Agency, Marine Environment Laboratories (Monaco)

2013-07-15

Post-Chernobyl trends of radioactive contamination of the Black Sea showed a relatively high rate of purification of its waters against soluble and particle reactive radionuclides. The apparent half-lives for the decrease of {sup 137}Cs and {sup 90}Sr concentrations in the central Black Sea waters was around 6 and 8 years, respectively, suggesting an additional {sup 90}Sr input by river runoff. These values, particularly for {sup 137}Cs, are considerably lower than in the adjacent Mediterranean basin ({approx}13 years), which is caused by faster dilution of {sup 137}Cs concentration in the upper Black Sea waters due to strong river discharge, and by loss of {sup 137}Cs via the Bosporus Strait. These factors, together with a higher rate of particle scavenging of plutonium in the mesotrophic Black Sea water, reflect its significant capability for self-cleaning against nuclear and non-nuclear pollutants, which was traced in this study using data on fluxes and time evolution of natural and anthropogenic radioactivity. (author)

Coccolithophores and calcite saturation state in the Baltic and Black Seas

Directory of Open Access Journals (Sweden)

T. Tyrrell

2008-04-01

Full Text Available The Baltic and Black Seas are both brackish, that is to say both have salinities intermediate between freshwater and seawater. The coccolithophore Emiliania huxleyi is abundant in one, the Black Sea, but absent from the other, the Baltic Sea. Here we present summertime coccolithophore measurements confirming this difference, as well as data on the calcium carbonate saturation state of the Baltic Sea. We find that the Baltic Sea becomes undersaturated (or nearly so in winter, with respect to both the aragonite and calcite mineral forms of CaCO₃. Data for the Black Sea are more limited, but it appears to remain strongly supersaturated year-round. The absence of E. huxleyi from the Baltic Sea could therefore potentially be explained by dissolution of their coccoliths in winter, suggesting that minimum annual (wintertime saturation states could be most important in determining future ocean acidification impacts. In addition to this potential importance of winter saturation state, alternative explanations are also possible, either related to differences in salinity or else to differences in silicate concentrations.

Difference of nitrogen-cycling microbes between shallow bay and deep-sea sediments in the South China Sea.

Science.gov (United States)

Yu, Tiantian; Li, Meng; Niu, Mingyang; Fan, Xibei; Liang, Wenyue; Wang, Fengping

2018-01-01

In marine sediments, microorganisms are known to play important roles in nitrogen cycling; however, the composition and quantity of microbes taking part in each process of nitrogen cycling are currently unclear. In this study, two different types of marine sediment samples (shallow bay and deep-sea sediments) in the South China Sea (SCS) were selected to investigate the microbial community involved in nitrogen cycling. The abundance and composition of prokaryotes and seven key functional genes involved in five processes of the nitrogen cycle [nitrogen fixation, nitrification, denitrification, dissimilatory nitrate reduction to ammonium (DNRA), and anaerobic ammonia oxidation (anammox)] were presented. The results showed that a higher abundance of denitrifiers was detected in shallow bay sediments, while a higher abundance of microbes involved in ammonia oxidation, anammox, and DNRA was found in the deep-sea sediments. Moreover, phylogenetic differentiation of bacterial amoA, nirS, nosZ, and nrfA sequences between the two types of sediments was also presented, suggesting environmental selection of microbes with the same geochemical functions but varying physiological properties.

The ships' ballast water impact on the Black Sea marine environment

Science.gov (United States)

Acomi, Nicoleta; Acomi, Ovidiu

2015-04-01

Ships use ballast water to provide stability during voyages. This type of seawater loaded on board from one geographical area and discharged in very different port areas as ballasting practice, turned into a vector for spreading the non-native sea life species. The reduction and limitation of invasive species is a problem that the modern world addresses. Thus, the International Maritime Organization (IMO) developed the BWM 2004 Convention. Adopting international regulations influences the socio-economic sector and this is the reason why the ballast water, the subject of this paper, has been on the IMO Marine Environment Protection Committee's agenda for more than 10 years, while the Convention has not yet been ratified and enforced. Although the Black Sea was subject to incidents regarding the invasive species the Romanian Government, as member of the IMO, did not ratify the Convention. The Black Sea was the subject of four major incidents regarding the ships' ballast water. One of them refers to the North American Comb Jelly, native from the Eastern Seaboard of America, introduced in the Black, Azov and Caspian Seas and seriously affecting the Romanian coastal environment in the 1990's. This invasive species has negative impacts: it reproduces rapidly under favourable conditions, it feeds excessively on zooplankton, it depletes zooplankton stocks, altering the food web and the ecosystem functionality, and contributed significantly to the collapse of Black and Azov Sea fisheries in the 1990s, with massive economic and social impact. There are studies for identifying the invasive species for the Black sea, structured in a database for marine species - the Black Sea Red Data Book. For these invasive species, there have been identified and developed charts to emphasize their ways of migration into the Black Sea. This paper aims to analyse the marine traffic in Romanian ports, broken down according with seasons and types of vessels, and to assess its relationship with

Centennial-scale records of total organic carbon in sediment cores from the South Yellow Sea, China

Science.gov (United States)

Zhu, Qing; Lin, Jia; Hong, Yuehui; Yuan, Lirong; Liu, Jinzhong; Xu, Xiaoming; Wang, Jianghai

2018-01-01

Global carbon cycling is a significant factor that controls climate change. The centennial-scale variations in total organic carbon (TOC) contents and its sources in marginal sea sediments may reflect the influence of human activities on global climate change. In this study, two fine-grained sediment cores from the Yellow Sea Cold Water Mass of the South Yellow Sea were used to systematically determine TOC contents and stable carbon isotope ratios. These results were combined with previous data of black carbon and 210Pb dating from which we reconstructed the centennial-scale initial sequences of TOC, terrigenous TOC (TOCter) and marine autogenous TOC (TOCmar) after selecting suitable models to correct the measured TOC (TOCcor). These sequences showed that the TOCter decreased with time in the both cores while the TOCmar increased, particularly the rapid growth in core H43 since the late 1960s. According to the correlation between the Huanghe (Yellow) River discharge and the TOCcor, TOCter, or TOCmar, we found that the TOCter in the two cores mainly derived from the Huanghe River and was transported by it, and that higher Huanghe River discharge could strengthen the decomposition of TOCmar. The newly obtained initial TOC sequences provide important insights into the interaction between human activities and natural processes.

Managing Rapana in the Black Sea: stakeholder workshops on both sides

NARCIS (Netherlands)

Janssen, R.; Knudsen, S.; Todorova, V.; Gündüz Hosgör, A.

2014-01-01

Rapana venosa is a non-indigenous invasive predator on bivalves in the Black Sea. A Rapana fishery has developed in the Black Sea since the 1980s, primarily in Turkey and Bulgaria. The Rapana fishery provides a complex management problem with three groups of objectives: 1. Good economic status; 2.

High-resolution metal gradients measured by in situ DGT/DET deployment in Black Sea sediments using an autonomous benthic lander RID G-2489-2010 RID A-4901-2009

DEFF Research Database (Denmark)

Fones, GR; Davison, W.; Holby, O.

2001-01-01

DET (Diffusive equilibration in thin films) and DGT (diffusive gradients in thin films) have been deployed in situ using an autonomous benthic lander to measure concentrations and induced fluxes of Fe and Mn (DET/DGT) and trace metals (DGT) in pore waters at millimeter spatial resolutions....... The newly developed deployment system is described, and based on these first results, its strengths and weaknesses are discussed. Deployments were made in the Western Black Sea in shelf sediments overlain by well-oxygenated water at a water depth of 77 m. Maxima of the redox-sensitive metals at 4 and 8 cm...... elements by several millimeters. Detection of this functional discrimination between Fe and Mn as regulators of trace metals would not have been possible using more conventional sampling procedures....

Anticancer potency of black sea cucumber (Holothuria atra) from Mentawai Islands, Indonesia

OpenAIRE

Mieke Hemiawati Satari; Utmi Arma; Syafruddin Ilyas; Dian Handayani

2017-01-01

ABSTRACT Introduction: The source of bioactive compounds believed to have strong anticancer potency is derived from sea cucumber. Black sea cucumber (Holothuria atra) is a dominant species in Mentawai Islands, West Sumatera, Indonesia. Key factor compound that acts as anticancer in sea cucumber extract is tritepenoid also known as Frondoside A. The purpose of this study was to determine the effectiveness of the active compound taken from black sea cucumber as anticancer. Methods: Methods u...

Riverine transport of Cs-137 and Sr-90 into the Black Sea after Chernobyl accident (data analysis and methodological aspects of monitoring)

International Nuclear Information System (INIS)

Kanivets, V.V.; Voitsekhovitch, O.V.; Khrystyk, B.F.

1999-01-01

Upper part of Dnieper catchment had been heavily contaminated after the Chernobyl accident and serves as a main source of the secondary input of radionuclides to the river. As a result of fast sorption of dissolved radiocesium by suspended sediments and sedimentation of contaminated particles to the bottom, practically all the 137 Cs having entered into the upper reaches of the Dnieper river after the Chernobyl accident was retained in the Dnieper reservoirs and the Dnieper-Bug estuary. Taking into account relatively high mobility of 90 Sr the extent of it's trapping by Dnieper reservoirs is significantly less comparatively to 137 Cs and accounted as some 60-70%. The Danube River catchment is characterized by less radioactive contamination, in comparison with the Dnieper catchment, and more homogeneous spatial distribution of this contamination. Suspended particles play a crucial role in 137 Cs transport by Danube to the Black Sea. Regular observations showed, that in average 60-70% of 137 Cs transport to the Black Sea is associated with suspended particles. The conditions for water selfpurification are absent on the Danube River due to the high velocity of the currents along the whole it length. Therefore, the significant portion of 137 Cs and other contaminants in particulate phase washed out from the upper part of basin can reach the Black Sea. The correct accounting of 137 Cs discharge on suspended particles by river strictly depends on representativity of samples used in calculation. Sampling procedure which had been done in uncorrect way could cause in significant underestimation of 137 Cs concentration up to 10 times. (author)

Satellite observation of bio-optical indicators related to North-Western Black Sea coastal zone changes

Science.gov (United States)

Zoran, Maria

Satellite remote sensing provides a means for locating, identifying and mapping certain coastal zone features and assessing of spatio-temporal changes.The Romanian coastal zone of the Black Sea is a mosaic of complex, interacting ecosystems, exposed to dramatic changes due to natural and anthropogenic causes (increase in the nutrient and pollutant load of rivers input, industrial and municipal wastewater pollution along the coast, and dumping on the open sea). This study focuses on the assessment of coastal zone land cover changes based on the fusion of satellite remote sensing data.The evaluation of coastal zone landscapes is based upon different sub-functions which refer to landscape features such as water, soil, land-use, buildings, groundwater, biotope types. Mixed pixels result when the sensor's instantaneous field-of-view includes more than one land cover class on the ground. Based on different satellite data (Landsat TM, ETM, SAR ERS, IKONOS, Quickbird, and MODIS) was performed object recognition for North-Western Black Sea coastal zone. Preliminary results show significant coastline position changes of North Western Black Sea during the period of 1987-2007 and urban growth of Constantza town. Also the change in the position of the coastline is examined and linked to the urban expansion in order to determine if the changes are natural or anthropogenic. A distinction is made between landfill/sedimentation processes on the one hand and dredging/erosion processes on the other. Waves play an important role for shoreline configuration. Wave pattern could induce erosion and sedimentation. A quasi-linear model was used to model the rate of shoreline change. The vectors of shoreline were used to compare with wave spectra model in order to examine the accuracy of the coastal erosion model. The shoreline rate modeled from vectors data of SAR ERS-1 has a good correlation with a quasi-linear model. Wave refraction patterns are a good index for shoreline erosion. A coast

MAIN FEATURES OF BALNEOLOGICAL AND MUD RESORTS NETWORK OF THE BLACK SEA COUNTRIES

OpenAIRE

Молодецький, А. Е.; Пишна, Г. О.

2016-01-01

Purpose. The aim of the article is the characteristics of geographical (natural and socio-economic) prerequisites for the development of coastal resorts of Black Sea region countries, with emphasis on balneological and mud-bath of recreational resources systems. Six European and Asian countries – Ukraine, Russia, Georgia, Turkey, Bulgaria and Romania have a diverse and significant resort and recreational resources of the Black Sea coast. However, for many decades the Black Sea resorts of thes...

Drivers, mechanisms and long term variability of bottom seasonal hypoxia in the Black Sea north-western Shelf. Is there any recovery after eutrophication ?

Science.gov (United States)

Capet, Arthur; Beckers, Jean-Marie; Grégoire, Marilaure

2013-04-01

The Black Sea North-western shelf (NWS) is a shallow eutrophic area in which seasonal stratification of the water column isolates bottom waters from the atmosphere and prevents ventilation to compensate for the large consumption of oxygen, due to respiration in the bottom waters and in the sediments. A 3D coupled physical biogeochemical model is used to investigate the dynamics of bottom hypoxia in the Black Sea NWS at different temporal scales from seasonal to interannual (1981-2009) and to differentiate the driving factors (climatic versus eutrophication) of hypoxic conditions in bottom waters. Model skills are evaluated by comparison with 14500 in-situ oxygen measurements available in the NOAA World Ocean Database and the Black Sea Commission data. The choice of skill metrics and data subselections orientate the validation procedure towards specific aspects of the oxygen dynamics, and prove the model's ability to resolve the seasonal cycle and interannual variability of oxygen concentration as well as the spatial location of the oxygen depleted waters and the specific threshold of hypoxia. During the period 1981-2009, each year exhibits seasonal bottom hypoxia at the end of summer. This phenomenon essentially covers the northern part of the NWS, receiving large inputs of nutrients from the Danube, Dniestr and Dniepr rivers, and extends, during the years of severe hypoxia, towards the Romanian Bay of Constanta. In order to explain the interannual variability of bottom hypoxia and to disentangle its drivers, a statistical model (multiple linear regression) is proposed using the long time series of model results as input variables. This statistical model gives a general relationships that links the intensity of hypoxia to eutrophication and climate related variables. The use of four predictors allows to reproduce 78% of hypoxia interannual variability: the annual nitrate discharge (N), the sea surface temperature in the month preceding stratification (T ), the

Caesium-137 distribution, inventories and accumulation history in the Baltic Sea sediments

International Nuclear Information System (INIS)

Zaborska, Agata; Winogradow, Aleksandra; Pempkowiak, Janusz

2014-01-01

The Baltic Sea is susceptible to pollution by hazardous substances due to limited water exchange, shallowness, and the large catchment area. Radionuclides, particularly 137 Cs, are one of the most hazardous anthropogenic substances present in the Baltic environment. This study was conducted to present 137 Cs present contamination that should further be a subject of reliable monitoring when the new Nuclear Power Plant is put into operation in the northern Poland. The sea-wide, up to date distribution of 137 Cs activities and inventories in the Baltic Sea bottom sediments are presented. The 137 Cs activity concentrations were measured in 30 cm long sediment cores collected at 22 sampling stations. Sediment accumulation rates were quantified by 210 Pb geochronology to follow the history of 137 Cs accumulation. The 137 Cs inventories and fluxes were calculated. Most of the Baltic Sea sediments accumulated 137 Cs in the range from 750 to 2675 Bq m −2 . The Bothnian Bay is severely contaminated by 137 Cs with inventories up to 95,191 Bq m −2 . This region is moreover characterized by extremely large patchiness of 137 Cs inventories. The 137 Cs annual fluxes are highest at the two stations located at the Bothnian Bay (342 Bq m −2 and 527 Bq m −2 ) due to large Chernobyl 137 Cs contamination of that region and high sediment accumulation rates. When these stations are excluded, the recent, annual mean value of 137 Cs load to the Baltic Sea deposits is 38 ± 22 Bq m −2 . The distribution of radio-caesium inventories over the Baltic Sea nowadays reflects the pattern of Chernobyl contamination. The radio-caesium deposited in surface sediments is not permanently buried, but may be resuspended and redeposited by currents, bioturbation or anthropogenic activities. -- Highlights: • 137 Cs contamination in the Baltic Sea was studied before the new NPP is put into operation. • Bothnian Sea sediments are severely contaminated by 137 Cs (inventories up to 95,191 Bq m �

Black Sea challenges; Les enjeux de la Mer Noire

Energy Technology Data Exchange (ETDEWEB)

Drevet, J F [Commission Europeenne, DG III, Bruxelles (Belgium)

2008-03-15

In this month's European column, Jean-Francois Drevet examines the issues that arise for Europe from the Black Sea region. The Black Sea is increasingly becoming a crucial place of transit for hydrocarbon imports from the Caspian and Russia into the European Union. The considerable increase in this traffic raises both environmental problems (the risk of oil slicks) and issues of security of supply, on account of the economic and political fragility of some of the bordering or neighbouring states (Ukraine, Georgia, Armenia, Azerbaijan, Russia/Chechnya etc.). This is why, as Jean-Francois Drevet stresses, the European Union has been trying since the mid-1990's to claim a role in the management of the affairs of the region. With two bordering states (Rumania and Bulgaria) joining the EU in 2007, cooperation in the Black Sea has become a priority within the framework of the European Neighbourhood Policy, and this column delineates a number of the obstacles that still have to be surmounted. (author)

Sulfate reduction in Black Sea sediments: in situ and laboratory radiotracer measurements from the shelf to 2000m depth

DEFF Research Database (Denmark)

Weber, A.; Riess, W.; Wenzhoefer, F.

2001-01-01

anoxic basin. The highest rates measured on an areal basis for the upper 0-15 cm were 1.97 mmol m(-2) d(-1) on the shelf and 1.54 mmol m(-2) d(-1) at 181 m water depth just below the chemocline. At all stations sulfate reduction rates decreased to values 50% just above the chemocline to 100% just below...... sediments showed that the present results tend to be higher in shelf sediments and lower in the deep-sea than most other data. Based on the present water column H2S inventory and the H2S flux out of the sediment, the calculated turnover time of H2S below the chemocline is 2100 years. (C) 2001 Elsevier...

The fate of long - lived radionuclides 137Cs and 90Sr in the Black Sea after Chernobyl NPP accident: results of twenty - year observations

International Nuclear Information System (INIS)

Stokozov, N. A.; Egorov, V. N.; Polikarpov, G. G.; Mirzoeva, N. Y.; Gulin, S. B.

2006-01-01

The presentation summarizes studies of 1 37Cs and 9 0Sr pollution of the Black Sea Basin carried out by Institute of Biology of the Southern Seas during 1986-2005 following the Chernobyl NPP accident. Its goal was to assess inflows of 1 37Cs and 9 0Sr from the Dnieper and the Danube Rivers, outflow through the Bosphorus Strait, inventories in bottom sediments and temporary evolution of 1 37Cs and 9 0Sr inventories in the Black Sea water column. Besides, the temporary evolution of 1 37Cs and 9 0Sr profiles in the Black Sea deep-water basin was used to estimations of a large-scale vertical water mixing. It has been estimated that the atmospheric fall outs during the first days of May 1986 have deposited 1.7-2.4 PBq of 1 37Cs on the Black Sea surface (nearly 2% of total 1 37Cs release in the environment). Therefore, 1 37Cs inventory in the 0-50 m layer have increased by a factor of 6-10 and the total 1 37Cs inventory in the whole basin have increased at least by a factor of 2 in comparison with the pre-Chernobyl value - 1.4+/-0.3 PBq. 1 37Cs input from the Danube and the Dnieper Rivers was insignificant in comparison with short-term atmospheric fall outs. The results of observations and mathematical modelling are testified that in the surface layers 0-50 and 0-200 m of the Black Sea deep-water basin in 1986-2000 an exponential decreases of the 1 37Cs inventories with an effective half-lifes of 5-6 years and 9-13 years, respectively, have been observed. The process of vertical water mixing has been observed mainly in the 0-200 m layer. The contribution of Chernobyl-origin 9 0Sr from atmospheric fallout was estimated around in 0.1-0.3 PBq. Pre-accident 9 0Sr level nearly 20 Bq m - 3 was reached by 1988. At the same time, an active input of 9 0Sr from the Dnieper and Danube Rivers has been observed. The total amount of 9 0Sr delivered by the two rivers into the Black Sea was estimated to be nearly 0.1 PBq in the 1986-1995. Under conditions of insignificant river input

Distribution and migration of ⁹⁰Sr in components of the Dnieper River basin and the Black Sea ecosystems after the Chernobyl NPP accident.

Science.gov (United States)

Mirzoyeva, N Yu; Egorov, V N; Polikarpov, G G

2013-11-01

The change in (90)Sr concentrations in hydrobionts, water and bottom sediments of the Chernobyl NPP pond-cooler, the Kievskoe and Kakhovskoe reservoirs, the Northern-Crimean canal and the Black Sea after the Chernobyl NPP accident was studied. The environmental half-times for the decrease of (90)Sr concentrations were determined: in water - 4.1-24.3 years; algae and flowering water plants - 3.6-7.7 years, in molluscs - 2.4-6.7 years, and in fish - 7.8-12.9 years. The time for (90)Sr concentrations to decrease to pre-accident levels were estimated: in freshwater reservoirs and the northwest part of the Black Sea this was 32-44 years, and in freshwater hydrobionts this was 25-73 years. The contribution of dose from (90)Sr to the hydrobionts, sampled from the Kakhovskoe reservoir, the Northern-Crimean canal and the Black Sea, has not reached values which could impact them during the entire post-accident period. This complex of comparative studies was carried out for the first time. Copyright © 2013 Elsevier Ltd. All rights reserved.

Comparison of manufactured and black carbon nanoparticle concentrations in aquatic sediments

International Nuclear Information System (INIS)

Koelmans, A.A.; Nowack, B.; Wiesner, M.R.

2009-01-01

In this paper, we show that concentrations of manufactured carbon-based nanoparticles (MCNPs) in aquatic sediments will be negligible compared to levels of black carbon nanoparticles (BCNPs). This is concluded from model calculations accounting for MCNP sedimentation fluxes, removal rates due to aggregation or degradation, and MCNP burial in deeper sediment layers. The resultant steady state MCNP levels are compared with BCNP levels calculated from soot levels in sediments and weight fractions of nanosized fractions of these soot particles. MCNP/BCNP ratios range from 10 -7 to 10 -4 (w:w). This suggests that the often acclaimed effect of MCNPs on organic pollutant binding and bioavailability will likely be below the level of detection if natural BCNPs are present, even if binding to MCNP is one to two orders of magnitude stronger than to BCNPs. Furthermore, exposure and toxic effects of MCNPs in sediments and soils will be negligible compared to that of BCNPs. - Concentrations of manufactured carbon-based nanoparticles in sediments and soils will be negligible compared to levels of black carbon (soot) nanoparticles

Economic Development of the Black Sea Riparian Countries during 2004-2012

Directory of Open Access Journals (Sweden)

Romeo Bosneagu

2014-05-01

Full Text Available The Black Sea is politically divided between the European Union, countries aspiring to join the EU and the Russian Federation. From an economic perspective, the area has a huge potential for development and is “claimed” by the same political actors. In 1992, BSEC (Black Sea Economic Cooperation was formed and it includes, along with the six riparian countries, eight countries in order to meet their economic power in order to achieve regional development. In the period 2004-2012 the economy Black Sea countries experienced strongly fluctuated, which was strongly connected to the global economy, the inflow of capital in the region and the influence of the global economic crisis.

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...

Wave modelling to assess the storm conditions in the Black Sea

Science.gov (United States)

Rusu, Liliana; Raileanu, Alina

2014-05-01

The work proposed herewith presents the results of a ten-year wave hindcast performed in the Black Sea and focused on the storm conditions. A wave modelling system, SWAN based, was implemented in the basin of the Black Sea. Validations have been performed both against in situ and remotely sensed data for the entire ten-year period considered (1999-2008). The wind field provided by NCEP-CFSR (United States National Centers for Environmental Prediction, Climate Forecast System Reanalysis) with a spatial resolution of 0.312ºx0.312º and a temporal resolution of 3 hours was considered for forcing the wave model. In statistical terms, the results are in general in line with those provided by similar wave prediction systems implemented in enclosed or semi-enclosed seas, the most important factors in increasing the general system reliability being the accuracy and resolution of the wind fields considered. As regards the physical processes, the calibration tests performed show that whitecapping still represents the weak link in deep water wave modelling. The most relevant storm conditions encountered in this ten-year period considered were further analysed. This analysis was performed from the point of view of the intensity, location of occurrence, duration and propagation in the geographical space of the storms. Following the results of the work, the western side of the sea is more energetic and almost each year storms with significant wave heights of about eight meters are encountered in this part of the Black Sea, while in the case of the extreme storms significant wave heights even greater than eleven meters may occur. From this perspective, it can be concluded that the present work provides valuable information about the characteristics of the storm conditions and on their dynamics in the Black Sea. Moreover, this marine environment is currently subjected to high navigation traffic and to offshore operations and the strong storms that systematically occur may produce

Comparing black carbon types in sequestering polybrominated diphenyl ethers (PBDEs) in sediments

International Nuclear Information System (INIS)

Jia, Fang; Gan, Jay

2014-01-01

Polybrominated diphenyl ethers (PBDEs) are widely found in sediments, especially congeners from the penta-BDE formula. Due to their strong affinity for black carbon (BC), bioavailability of PBDEs may be decreased in BC-amended sediments. In this study, we used a matrix-SPME method to measure the freely dissolved concentration (C free ) of PBDEs as a parameter of their potential bioavailability and evaluated the differences among biochar, charcoal, and activated carbon. Activated carbon displayed a substantially greater sequestration capacity than biochar or charcoal. At 1% amendment rate in sediment with low organic carbon (OC) content (0.12%), C free of six PBDEs was reduced by 47.5–78.0%, 47.3–77.5%, and 94.1–98.3% with biochar, charcoal, and activated carbon, respectively, while the sequestration was more limited in sediment with high OC content (0.87%). Therefore, it is important to consider the type and properties of the BC and the sediment in BC-based remediation or mitigation. -- Highlights: • A matrix-SPME method was developed for measuring C free of PBDEs in sediment porewater. • Different black carbon types differed greatly in their ability to decrease C free of PBDEs in sediments. • Activated carbon was much more efficient in sequestering PBDEs than biochar or charcoal. • The effect of black carbon was more pronounced in sediment with lower indigenous OC content. -- Biochar, charcoal, and activated carbon have been compared for their efficacy in sequestering PBDEs in sediments by using a matrix-SPME method

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.

Oxygen, nitrogen and sulphide fluxes in the Black Sea

Directory of Open Access Journals (Sweden)

S.K. KONOVALOV

2000-12-01

Full Text Available The fluxes and production/consumption rates of oxygen, nitrate, ammonium and sulphide are estimated in the paper utilising results of the 1.5-dimensional stationary model of vertical exchange in the Black Sea (Samodurov & Ivanov, 1998. The profiles of the vertical flux and rate of production/consumption of these substances have revealed a number of intriguing features in the biogeochemical nature of the Black Sea. An approximate redox balance of the counter-fluxes of nitrate and ammonium into the sub-oxic zone has been revealed confirming that intensive denitrification may be the primary loss of nitrogen in the Black Sea. A low ratio of the nitrate stock to the flux of nitrate from the oxycline confirms the possibility of prominent changes in the distribution of nitrate on the time scale of a year. The ratio of the nitrate to oxygen vertical flux has revealed a lack of nitrate in the oxycline above the nitrate maximum. The lateral (related to the "Bosporus plume" flux of oxygen in the layer of the main pycnocline appears to be very important for the existing biogeochemical structure of the Black sea water column being the reason of sulphide consumption inside the anoxic zone and changes in the ammonium-sulphide stoichiometry of the anoxic zone, the primary reason of the existence of the sub-oxic layer and the basic reason of relative stability of the sulphide onset.

Phosphate solubilizing bacteria: Comparison between coastal and deep sea sediments

Digital Repository Service at National Institute of Oceanography (India)

Biche, S.; Pandey, S.; Gonsalves, M.J.B.D.; Das, A.; Mascarenhas-Pereira, M.B.L.; LokaBharathi, P.A.

in the CIB sediments (r=0.59) than in the coastal sediments (r= 0.22). It is apparent that the enzyme activity in the coastal sediments could be more for P mobilization and in the oligotrophic deep sea it could be both for P and C mobilization....

Sedimentation rate in the Baltic Sea

International Nuclear Information System (INIS)

Ilus, E.; Mattila, J.; Klemola, S.; Ikaeheimonen, T.K.; Niemisto, L.

2001-01-01

Varying redox conditions may affect the occurrence and concentrations of certain radionuclides in the surface layers of sediments and in near-bottom waters by causing remobilization of radionuclides from surface sediments to the overlying water and their settling back into the sediment. In recent decades about 70.000 km 2 of the sea bottom in the deepest part of the Baltic Sea (about 19% of its total area) have withstood almost continuous anoxic conditions; thus, it is important to know to what extent depletion of oxygen can affect the behaviour of these radionuclides in near-bottom waters. The aim of the project was to resolve the above question in a coastal basin periodically undergoing anoxic conditions. Radioecological processes in sediments and in near-bottom water under varying redoxconditions were studied in the deep area of the Haestholmsfjaerden Bay in Loviisa (eastern Gulf of Finland) in 1995-1996. The Haestholmsfjaerden Bay is a semienclosed basin between the mainland and the archipelago and is connected with the open Gulf of Finland only through narrow, shallow sounds: In 1995, total depletion of oxygen occurred in the hypolimnion of Haestholmsfjaerden Bay during 2 periods in late summer and autumn. In 1996, oxygen conditions were the worst ever observed in the Haestholmsfjaerden deep. During early autumn anoxic conditions prevailed for more than 1 month in the near-bottom water. The highest total phosphorus and total nitrogen concentrations in the near-bottom water during these periods were 20- and 4- fold compared with the corresponding values in surface water. According to the results obtained in this project, remobilization of 137 Cs and 239,240 Pu from sediments to near-bottom water is negligible or non-existent in the Haestholmsfjaerden deep. If it does occur, however, it may be so slight that it is not possible to observe with the methods used in this study. Although the anoxic periods are quite short in the Haestholmsfjaerden deep, they are of

Potential economic impacts of achieving good environmental status in Black Sea fisheries

Directory of Open Access Journals (Sweden)

Ian C. Goulding

2014-09-01

Full Text Available The Marine Strategy Framework Directive (MSFD mandates that European Union (EU member states achieve Good Environmental Status (GEnS based on an ecosystem-based approach to management. For commercial fisheries, the primary target under the MSFD is one of maximum sustainable yield. Of Black Sea riparian nations, only Romania and Bulgaria are EU member states. Focusing at the supranational level, we review institutions and instruments relevant to management of the Black Sea. The economic values of current fish catches are assessed, and the results of a recent analytical assessment of fish stocks are used to estimate potential future values based on maximum sustainable yields. In the Black Sea region, despite long-standing attempts to improve fisheries management, there remains a lack of effective regional cooperation. Evidence from the scenario analysis suggests that achieving GEnS would not have an undue negative impact on overall fishery sector incomes, and could, with appropriate investments in processing and marketing, deliver increased economic benefits for Black Sea countries. The ongoing policy debate between and within Black Sea coastal states needs to be extended to include recognition of the potential economic and social benefits of effective fisheries management. More work is required to assess returns on investment in interim management measures to deliver GEnS.

Exchanges between the open Black Sea and its North West shelf

Science.gov (United States)

Shapiro, Georgy; Wobus, Fred; Zhou, Feng

2014-05-01

Exchanges between the vast NW shelf and the deep basin of the Black Sea play a significant role in maintaining the balance of nutrients, heat content and salinity of the shelf waters. Nearly 87 % of the Black Sea is entirely anoxic below 70 to 200m and contains high levels of hydrogen sulphide (Zaitsev et al, 2001), and this makes the shelf waters particularly valuable for maintaining the Black Sea ecosystem in good health. The increase in salinity of shelf waters occurs partially due to exchanges with more saline open sea waters and represents a threat to relics and endemic species. The shelf-break is commonly considered the bottle-neck of the shelf-deep sea exchanges (e.g. (Huthnance, 1995, Ivanov et al, 1997). Due to conservation of potential vorticity, the geostrophic currents flow along the contours of constant depth. However the ageostrophic flows (Ekman drift, mesoscale eddies, filaments, internal waves) are not subject to the same constraints. It has been shown that during the winter well mixed cold waters formed on the North West shelf propagate into the deep sea, providing an important mechanism for the replenishment of the Cold Intermediate Layer ( Staneva and Stanev, 1997). However, much less is known about exchanges in the warm season. In this study, the transports of water, heat and salt between the northwestern shelf and the adjacent deep basin of the Black Sea are investigated using a high-resolution three-dimensional primitive equation model, NEMO-SHELF-BLS (Shapiro et al, 2013). It is shown that during the period from April to August, 2005, both onshore and offshore cross-shelf break transports in the top 20 m were as high as 0.24 Sv on average, which was equivalent to the replacement of 60% of the volume of surface shelf waters (0 - 20 m) per month. Two main exchange mechanisms are studied: (i) Ekman transport, and (ii) transport by mesoscale eddies and associated meanders of the Rim Current. The Ekman drift causes nearly uniform onshore or

Environmental assessment of rosetta area,mediterranean sea coast - egypt

International Nuclear Information System (INIS)

Aly, A.M.A.

2013-01-01

This study is titled (Environmental Assessment of Rosetta Area,Mediterranean Sea Coast, Egypt). The environmental assessment can be defined here as the process of assessing the potential impacts (positive or negative) of the presence of certain influential on a particular ecosystem. Samples were collected from Abu Khashaba beach area, Rosetta on the Mediterranean Sea coast. Samples of the beach sediments, sea-water and the scattered shells in this coastal region were collected. Sediments in this region are characterized by its large content of heavy metals, which added to these sediments its black color. It is known that these black sands occurred along the Mediterranean Sea coast from Alexandria to Rafah. The advantage of these black sand deposits is their contents from multiple economic metals which have important industrial uses, such as magnetite, ilmenite, rutile, monazite, zircon, garnet and other important minerals. Ten sampling profiles spaced in-between by about 600 m distance, and extending into the land from the shoreline for about 50 m or less. Along each profile, three sediment samples were collected; the first sample from the surface at the beach line, the second sample from the end of the foreshore area at a depth of about 50 cm and the third sample was taken from the backshore area at a depth of about 1 m. Extending from each profile into the sea, marine-water samples were taken at a distance of about 3 m from the beach line, and from a depth of about 1 m below the sea surface. The shells samples were collected from the scattered shells on the beach. By examination of these samples a 15 different shells types were defined.

A success story of regional projects implemented for the management of marine environment. Turkish experience related to the black sea and the mediterranean sea

International Nuclear Information System (INIS)

Goktepe, B.G.; Gungor, N.; Gungor, E.; Karakelle, B.

2004-01-01

Full text: A wide scope Regional Technical Co-operation Project RER/2/003 'Marine Environmental Assessment of the Black Sea Region' is implemented by the International Atomic Energy Agency (IAEA) in the period 1995-2001. This project was initiated in response to the needs of participating Member States - the six Black Sea coastal countries (Bulgaria, Romania, Ukraine, Russian Federation, Georgia and Turkey) to establish capabilities for reliably assessing radionuclides in the Black Sea environment and applying tracer techniques to marine pollution studies The project has various important aspects: Scientifically; one of the major environmental issue radioactivity pollution is addressed. Technically; laboratory capability for transuranic analysis is being developed. Economically; the reversing the ecological deterioration and developing sustainable uses of the Black Sea and its natural resources is one of the major interests. Politically; responsibility of pollution control and rehabilitation plans of six Black Sea countries are addressed through various convention and declarations. Socio-economically, fisheries and tourism sectors are expected to benefit. Highlights from the joint radioactivity-monitoring program of the project among six Black Sea countries are outlined. Examples from the Turkish monitoring work consist of the routine sampling of seawater, algae, mussels, fish samples and beach sand from the selected stations along the Black Sea coast are presented for illustration. The success of the Black Sea regional project has given rise to a new regional project 'Marine Environmental Assessment of the Mediterranean Region' based on the request of the member countries, which will be initiated in 2005 by the IAEA. The initial phase the project, its objectives and the schedule will be summarized. Key words: marine radioactivity, environmental management, Black Sea, Mediterranean Sea, regional cooperation

Comparison of manufactured and black carbon nanoparticle concentrations in aquatic sediments

NARCIS (Netherlands)

Koelmans, A.A.; Nowack, B.; Wiesner, M.

2009-01-01

In this paper, we show that concentrations of manufactured carbon-based nanoparticles (MCNPs) in aquatic sediments will be negligible compared to levels of black carbon nanoparticles (BCNPs). This is concluded from model calculations accounting for MCNP sedimentation fluxes, removal rates due to

Wind waves in the Black Sea: results of a hindcast study

Science.gov (United States)

Arkhipkin, V. S.; Gippius, F. N.; Koltermann, K. P.; Surkova, G. V.

2014-11-01

In this study we describe the wind wave fields in the Black Sea. The general aims of the work were the estimation of statistical wave parameters and the assessment of interannual and seasonal wave parameter variability. The domain of this study was the entire Black Sea. Wave parameters were calculated by means of the SWAN wave model on a 5 × 5 km rectangular grid. Initial conditions (wind speed and direction) for the period between 1949 and 2010 were derived from the NCEP/NCAR reanalysis. According to our calculations the average significant wave height on the Black Sea does not exceed 0.7 m. Areas of most significant heavy sea are the southwestern and the northeastern parts of the sea as expressed in the spatial distribution of significant wave heights, wave lengths and periods. Besides, long-term annual variations of wave parameters were estimated. Thus, linear trends of the annual total duration of storms and of their quantity are nearly stable over the hindcast period. However, an intensification of storm activity is observed in the 1960s-1970s.

THE ECONOMY AND ENERGY OF THE BLACK SEA REGION

Directory of Open Access Journals (Sweden)

Maria-Floriana Popescu

2014-12-01

Full Text Available The Black Sea region has proved to be an emerging hub for Europe’s security and has experienced several changes and a great development at the beginning of the twenty-first century. This process is currently carried out, and has important implications for European security in a broader definition of the term - to achieve traditional military security, but also tackling other challenges at the address soft security issues, such as organized crime. Located at the crossroads of three regions of paramount importance - Europe, Middle East and Central Asia – the Black Sea region is a major transit area for energy and at the same time, an important source of asymmetric risks and outbreaks of conflicts. Therefore, analysing this region from an economical point of view, but not forgetting the energy security implications for this area, represents the main focus of this article, along with underlining the importance of various actors in the region and their actions’ impact on the future development of the Black Sea territory and surroundings.

Air-sea exchange over Black Sea estimated from high resolution regional climate simulations

Science.gov (United States)

Velea, Liliana; Bojariu, Roxana; Cica, Roxana

2013-04-01

Black Sea is an important influencing factor for the climate of bordering countries, showing cyclogenetic activity (Trigo et al, 1999) and influencing Mediterranean cyclones passing over. As for other seas, standard observations of the atmosphere are limited in time and space and available observation-based estimations of air-sea exchange terms present quite large ranges of uncertainty. The reanalysis datasets (e.g. ERA produced by ECMWF) provide promising validation estimates of climatic characteristics against the ones in available climatic data (Schrum et al, 2001), while cannot reproduce some local features due to relatively coarse horizontal resolution. Detailed and realistic information on smaller-scale processes are foreseen to be provided by regional climate models, due to continuous improvements of physical parameterizations and numerical solutions and thus affording simulations at high spatial resolution. The aim of the study is to assess the potential of three regional climate models in reproducing known climatological characteristics of air-sea exchange over Black Sea, as well as to explore the added value of the model compared to the input (reanalysis) data. We employ results of long-term (1961-2000) simulations performed within ENSEMBLE project (http://ensemblesrt3.dmi.dk/) using models ETHZ-CLM, CNRM-ALADIN, METO-HadCM, for which the integration domain covers the whole area of interest. The analysis is performed for the entire basin for several variables entering the heat and water budget terms and available as direct output from the models, at seasonal and annual scale. A comparison with independent data (ERA-INTERIM) and findings from other studies (e.g. Schrum et al, 2001) is also presented. References: Schrum, C., Staneva, J., Stanev, E. and Ozsoy, E., 2001: Air-sea exchange in the Black Sea estimated from atmospheric analysis for the period 1979-1993, J. Marine Systems, 31, 3-19 Trigo, I. F., T. D. Davies, and G. R. Bigg (1999): Objective

Black Sea ecology. Pollution research in Turkey of the marine environment

International Nuclear Information System (INIS)

Topcuoglu, Sayhan

2000-01-01

Scientific research is leading to answers that can help protect the Black Sea marine environment. Through projects supported by the IAEA and other cooperative channels, countries in the Black Sea region are applying their expertise and capabilities to expand scientific knowledge of chemical and radioactive pollution. Turkey stands among the countries engaged in studies of the Black Sea, for a number of reasons related to environmental, economic, and health issues. Our scientific knowledge of pollution problems in the marine environment promises to expand in years ahead. Advances in the integration of biokinetic, ecotoxicology and risk analysis with environmental monitoring studies could make it possible to eventually determine the sensitivity to pollutants of human populations and marine organisms. Such integrated studies are being conducted by the Radioecology Laboratory of Cekmece Nuclear Research and Training Center (CNAEM) in Turkey. The Laboratory has gained considerable experience over the years, including through its collaboration since 1970 with the IAEA's Marine Environment Laboratory (MEL) in Monaco. Agency technical cooperation projects and research programmes additionally have benefited the laboratory. This article highlights selected Turkish studies of the Black Sea related to both radioactive and chemical pollution

Solutions for reducing dissolved hydrogen sulphide in the Black Sea by electrochemical oxidation

International Nuclear Information System (INIS)

Ciocanea, Adrian; Budea, Sanda; Radulescu, Gabriel

2007-01-01

Anaerobic disintegration of organic matter is a particular phenomenon in the Black Sea because of the set up of deposits of hydrogen sulphide, H 2 S, having high concentrations. The formation of such deposits is due to the absence of upward streams at depths larger than 100 meters. In Black Sea there is an oxic layer located roughly between 50 and 200 meters from which downwards begins the anoxic layer. If the equilibrium in Black Sea is not kept under control, an ecological disaster is possible. The first signals will be observed in surface waters, than, if the equilibrium is further disturbed the depth sulphides and the hydrogen sulphide deposits can develop up to inflammable and even explosive phases. This paper presents some solutions to reduce the hydrogen sulphide from Black Sea with a particular stress upon the electrochemical method. (authors)

Methods in mooring deep sea sediment traps

Digital Repository Service at National Institute of Oceanography (India)

Venkatesan, R.; Fernando, V.; Rajaraman, V.S.; Janakiraman, G.

The experience gained during the process of deployment and retrieval of nearly 39 sets of deep sea sediment trap moorings on various ships like FS Sonne, ORV Sagarkanya and DSV Nand Rachit are outlined. The various problems encountered...

Vertical distribution of 241Pu in the southern Baltic Sea sediments

International Nuclear Information System (INIS)

Strumińska-Parulska, Dagmara I.

2014-01-01

Highlights: • The unique study on 241 Pu in sediments from the southern Baltic Sea was presented. • 241 Pu was determined using alpha spectrometry by indirect method. • The biggest amount of 241 Pu existed in the surface layers of all analyzed sediments. • The highest 241 Pu amount comes from the Chernobyl accident. - Abstract: The vertical distribution of plutonium 241 Pu in marine sediments can assist in determining the deposition history and sedimentation process of analyzed regions. In addition, 241 Pu/ 239+240 Pu activity ratio could be used as a sensitive fingerprint for radioactive source identification. The present preliminary studies on vertical distribution of 241 Pu in sediments from four regions of the southern Baltic Sea are presented. The distribution of 241 Pu was not uniform and depended on sediment geomorphology and depth as well as location. The highest concentrations of plutonium were found in the surface layers of all analyzed sediments and originated from the Chernobyl accident

Long-term variability of extreme waves in the Caspian, Black, Azov and Baltic Seas

Science.gov (United States)

Arkhipkin, Victor; Dobroliubov, Sergey

2013-04-01

In order to study extreme storm waves in the Caspian, Black, Azov and Baltic Sea we used the spectral wave model SWAN. Significant wave height, swell and sea height, direction of propagation, their length and period were calculated with the NCEP/NCAR (1,9°x1,9°, 4-daily) reanalysis wind forcing from 1948 to 2010 in the Caspian, Black and Baltic Seas and with the NCEP/CFSR (0,3°x0,3°, 1 hour) for the period from 1979 to 2010 in the Azov Sea. The calculations were performed on supercomputers of Lomonosov Moscow State University (MSU). The spatial resolution of the numerical grid was of order 5 km for the Caspian, Baltic and Black Seas, 2 km for the Azov Sea. These model wave hindcasts were used to calculate interannual and seasonal variability of the storm frequency, location and duration. The Initial Distribution Method and Annual Maxima Series Methods were used to study probable waves of a century reoccurrence. The long-term variability of extreme waves revealed different trends in the investigated seas. The Caspian and Azov seas decreased the storm activity, while in the Baltic Sea the number of storm cases increased and the Black Sea showed no significant trend. The of more than 12 m were observed in two centers in the middle part of the Caspian Sea and in the center of the Baltic Sea. In the Black Sea the extreme waves of the same probability of more than 14 m were found in the region to the south of the Crimean peninsula. In the Azov Sea the highest waves of a century reoccurrence do not exceed 5 m. The work was done in Natural Risk Assessment Laboratory, MSU under contract G.34.31.0007.

Drivers, mechanisms and long-term variability of seasonal hypoxia on the Black Sea northwestern shelf - is there any recovery after eutrophication?

Science.gov (United States)

Capet, A.; Beckers, J.-M.; Grégoire, M.

2013-06-01

The Black Sea northwestern shelf (NWS) is a shallow eutrophic area in which the seasonal stratification of the water column isolates the bottom waters from the atmosphere. This prevents ventilation from counterbalancing the large consumption of oxygen due to respiration in the bottom waters and in the sediments, and sets the stage for the development of seasonal hypoxia. A three-dimensional (3-D) coupled physical-biogeochemical model is used to investigate the dynamics of bottom hypoxia in the Black Sea NWS, first at seasonal and then at interannual scales (1981-2009), and to differentiate its driving factors (climatic versus eutrophication). Model skills are evaluated by a quantitative comparison of the model results to 14 123 in situ oxygen measurements available in the NOAA World Ocean and the Black Sea Commission databases, using different error metrics. This validation exercise shows that the model is able to represent the seasonal and interannual variability of the oxygen concentration and of the occurrence of hypoxia, as well as the spatial distribution of oxygen-depleted waters. During the period 1981-2009, each year exhibits seasonal bottom hypoxia at the end of summer. This phenomenon essentially covers the northern part of the NWS - which receives large inputs of nutrients from the Danube, Dniester and Dnieper rivers - and extends, during the years of severe hypoxia, towards the Romanian bay of Constanta. An index H which merges the aspects of the spatial and temporal extension of the hypoxic event is proposed to quantify, for each year, the intensity of hypoxia as an environmental stressor. In order to explain the interannual variability of H and to disentangle its drivers, we analyze the long time series of model results by means of a stepwise multiple linear regression. This statistical model gives a general relationship that links the intensity of hypoxia to eutrophication and climate-related variables. A total of 82% of the interannual variability

Comparative bioavailability of radionuclides in macroalgae from Black sea coastal environment

International Nuclear Information System (INIS)

Strezov, A.; Nonova, Tz.; Christoskova, M.

2004-01-01

Radionuclide and heavy metal content is measured by gamma spectroscopy and Atomic Absorption Spectroscopy in the commonest species of the Black Sea red, brown, and green macroalgae, sampled in the period 1996 - 2002. Radionuclide content was measured in ten different macrophytic algae species (five green: Cladophora vagabunda, Ulva rigida, Enteromorpha intestinal, Chaetomorpha gracilis, Bryopsis plumosa; two brown: Cystoseira crinita and Cystoseira barbata; three red: Ceramium rubrum, Callithamnium corymbosum, Corallina officinalis) from eleven sampling locations for eight consecutive years. The measured concentrations of artificial and natural gamma emitters in algae depend on the alga species. The obtained range for 137 Cs in algae is 1.2 - 26 Bq/kg. The average values for the natural nuclides are 238 U - 13 Bq/kg; 232 Th - 6 Bq/kg and for 226 Ra - 8 Bq/kg. The measured natural nuclides in the species Bryopsis plumosa are with two orders of magnitude higher than other species at the same location. Significant differences in Cs-137 concentrations were found among different species growing under similar environmental conditions at same locations, suggesting that uptake does not follow physical levels but influenced by allometric parameters and physiological mechanisms. Cs-137 content in collected sea algae follows the descending order: Ceramium rubrum , Cladophora vagabunda, Cystoseira barbata, Cystoseira crinita, Enteromorpha intestinalis, Ulva rigida, Callithamnium corymbosum, Corallina officinalis, Chaetomorpha gracilis. A comparison of the stations studied indicated that the accumulation degree is also dependent on the geomorphology of the specific area. Higher levels are obtained in the northern part of the Black Sea basin due to current circulation originating from the outflow of the rivers Danube, Dnyepr and Dnester, also at the south part of the Black sea coast. It is concluded that the general dispersion of Cs-137 results from the water circulation regime

Analysis of Complex Marine Hazards on the Romanian Black Sea Shelf Using Combined Geophysical Methods

Science.gov (United States)

Samoila, I. V.; Radulescu, V.; Moise, G.; Diaconu, A.; Radulescu, R.

2017-12-01

Combined geophysical acquisition technologies including High Resolution 2D Seismic (HR2D), Multi-Beam Echo-Sounding (MBES), Sub-Bottom Profiling (SBP) and Magnetometry were used in the Western Black Sea (offshore Romania) to identify possible geohazards, such as gas escaping surface sediments and tectonic hazard areas up to 1 km below the seafloor. The National Project was funded by the Research and Innovation Ministry of Romania, and has taken place over 1.5 years with the purpose of creating risk maps for the surveyed pilot area. Using an array of geophysical methods and creating a workflow to identify geohazard susceptible areas on the Romanian Black Sea continental shelf is important and beneficial for future research projects. The SBP and MBES data show disturbed areas that can be interpreted as gas escapes on the surface of the seafloor, and some escapes were confirmed on the HR2D profiles. Shallow gas indicators like gas chimneys and acoustic blanking are usually delimited by vertical, sub-vertical and/or quasi-horizontal faults that mark possible hazard areas on shallow sedimentary sections. Interpreted seismic profiles show three main markers: one delimiting the Pliocene-Quaternary boundary and two for the Miocene (Upper and Lower). Vertical and quasi-horizontal faults are characteristic for the Upper Miocene, while the Lower Miocene has NW-SE horizontal faults. Faults and possible hazard areas were marked on seismic sections and were further correlated with the MBES, SBP, Magnetometry and previously recorded data, such as earthquake epicenters scattered offshore in the Western Black Sea. The main fault systems likely to cause those earthquakes also aid the migration of gas if the faults are not sealed. We observed that the gas escapes were correlated with faults described on the recent seismic profiles. Mapping hazard areas will have an important contribution to better understand the recent evolution of the Western Black Sea basin but also for projecting

Distribution of organic carbon in sediments from the Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Paropkari, A.L.; Mascarenhas, A.; PrakashBabu, C.

Many earlier studies on the distribution of organic carbon in the Arabian Sea, sediments have projected contradictory opinions on the factors favouring accumulation and preservation of organic carbon in the Arabian Sea. An attempt is made...

Black Sea Governorate during World War I: A Historiographical Survey

Directory of Open Access Journals (Sweden)

Lyubov G. Polyakova

2015-06-01

Full Text Available This survey article addresses the historiography of World War I in the territory of Black Sea Governorate. The author singles out three chronological periods, ante-revolutionary, Soviet, and present-day Russian, and discusses distinctive characteristics in the study of the history of each of the periods. Thus, for instance, a distinctive trait in the study of World War I during the Soviet period was a permanent search in it for preconditions for the socialist revolution, which led to the artificial politicization of events and phenomena. The author comes to the conclusion that the historiography of World War I in the territory of Black Sea Governorate has considerable gaps, while the topic itself is yet to become the subject of comprehensive study. Up until the present day the following topics have remained virtually unstudied: the activity of the hospital framework across Black Sea Governorate, the identification of distinctive characteristics of combating alcoholism during the war, and the activity of charity societies.

Uranium in Pacific Deep-Sea Sediments and Manganese Nodules

DEFF Research Database (Denmark)

Kunzendorf, Helmar; Pluger, W. L.; Friedrich, G. H.

1983-01-01

A total of 1344 manganese nodules and 187 pelagic sediments from 9 areas in the North and the South Pacific were analyzed for U by the delayed-neutron counting technique. A strong positive correlation between U and Fe in nodules and sediments suggests a co-precipitative removal from sea water int...

Migration of trace heavy metals at the sea water/sediment interface

International Nuclear Information System (INIS)

Terada, Kikuo; Tomiyama, Chisato

1984-01-01

Migration behavior of some trace heavy metals such as Co(II), Cu(II), Mn(II) and Zn(II) at the sea water/sediment interface was investigated by tank experiments. The sea water which was doped with these metal ions (ppb to ppm levels) allowed to contact with the raw-, ignited- and autoclaved-marine sediments and the change of the concentration of each metal was traced at definite time intervals. At the end of the experiments, a core sample of the sediment was taken and analyzed for each metal in every 1 mm thick segment. On the other hand, the surface sediment was submitted to partial extraction with various kinds of reagents to estimate the chemical species of the metals captured in the sediment. While every metal ion was quickly adsorbed on surface of the raw sediment, a concentration gradient from surface to bottom of the water phase occurred in the ignited sediment system. The migration of manganese to the sediment phase was assumed to be concerned with bacterial activity in the sediment. Copper and zinc seemed to be adsorbed very quickly onto some fine sediment particles by the formation of organometallic complexes with some organic materials existing in the sediments. Cobalt migrated relatively fast downward within the sediment phase after its deposition. (author)

Determination of sedimentation, diffusion, and mixing rates in coastal sediments of the eastern Red Sea via natural and anthropogenic fallout radionuclides.

Science.gov (United States)

Al-Mur, Bandar A; Quicksall, Andrew N; Kaste, James M

2017-09-15

The Red Sea is a unique ecosystem with high biodiversity in one of the warmest regions of the world. In the last five decades, Red Sea coastal development has rapidly increased. Sediments from continental margins are delivered to depths by advection and diffusion-like processes which are difficult to quantify yet provide invaluable data to researchers. Beryllium-7, lead-210 and ceseium-137 were analyzed from sediment cores from the near-coast Red Sea near Jeddah, Saudi Arabia. The results of this work are the first estimates of diffusion, mixing, and sedimentation rates of the Red Sea coastal sediments. Maximum chemical diffusion and particle mixing rates range from 69.1 to 380cm -2 y -1 and 2.54 to 6.80cm -2 y -1 , respectively. Sedimentation rate is constrained to approximately 0.6cm/yr via multiple methods. These data provide baselines for tracking changes in various environmental problems including erosion, marine benthic ecosystem silting, and particle-bound contaminant delivery to the seafloor. Copyright © 2017. Published by Elsevier Ltd.

Danube paleohydrology: Hyperspectral and sedimentological high-resultion study of the last glacial Black Sea rythmites

Science.gov (United States)

Martinez Lamas, R.; Debret, M.; Deloffre, J.; Toucanne, S.

2017-12-01

The Black Sea has undergone alternating phases of lacustrine and marine environment over geological timescales directly related to its semi-enclosed character and to eustatic sea-level oscillations. During lowstand conditions, as during the last glacial period, the Black Sea was a giant lake disconnected from the global ocean. At that time, Black Sea water-level was controlled by regional climate, and by Eurasian rivers, including the Danube that acted as an outlet of European Ice Sheet and the Alpine ice cap. Thus, the paleo-mouth of the Danube river contains a high quality archive for the study of the paleohydrology of the Danube River and by extension of the European climate changes during the last 30 kyr. For this purpose, we have focused on the GAS-CS01 calypso long-piston core (33.4 m) which was taken during GHASS cruise (Ifremer, 2015) on the upper slope (240 m. depth) at about 25 km east of the Danube Canyon, i.e. in the sediment pile of the Danube paleo-mouth during the last glacial period. Our chronology reveals that core GAS-CS01 extends back to 31 cal kyr BP. The lithology of GAS-CS01 is characterized by clastic rythmites which are presented as a high-resolution Danube runoff proxy. Preliminary results of sedimentological and chronological analysis showed five peaks of terrestrial discharges between ca 31 and 14 ka BP, probably linked to five phases of the enhanced runoff during the studied period. In order to understand the origin and the depositional processes of this laminae, we combined sedimentary analysis (x-ray diffraction, x-ray fluorescence, grain size ...) and hyperspectral images analysis. Hyperspectral imagery is a non-destructive fast method classically used to quantify colour and provides data with high spatial (57-µm pixel size) and spectral (3 nm) resolution. The multi-proxy calibration is essential in order to obtain a high-resolution sedimentological dataset. This information allows us to reconstruct the nature and depositional

Copper in the sediment and sea surface microlayer near a fallowed, open-net fish farm.

Science.gov (United States)

Loucks, Ronald H; Smith, Ruth E; Fisher, Clyde V; Fisher, E Brian

2012-09-01

Sediment and sea surface microlayer samples near an open-net salmon farm in Nova Scotia, were analysed for copper. Copper is a constituent of the feed and is an active ingredient of anti-foulants. The salmon farm was placed in fallow after 15 years of production. Sampling was pursued over 27 months. Elevated copper concentrations in the sediments indicated the farm site as a source. Bubble flotation due to gas-emitting sediments from eutrophication is a likely process for accumulating copper in the sea surface microlayer at enriched concentrations. Elevated and enriched concentrations in the sea surface microlayer over distance from the farm site led, as a result of wind-drift, to an enlarged farm footprint. The levels of copper in both sediments and sea surface microlayer exceeded guidelines for protection of marine life. Over the 27 months period, copper levels persisted in the sediments and decreased gradually in the sea surface microlayer. Copyright © 2012 Elsevier Ltd. All rights reserved.

Exploring fungal diversity in deep-sea sediments from Okinawa Trough using high-throughput Illumina sequencing

Science.gov (United States)

Zhang, Xiao-Yong; Wang, Guang-Hua; Xu, Xin-Ya; Nong, Xu-Hua; Wang, Jie; Amin, Muhammad; Qi, Shu-Hua

2016-10-01

The present study investigated the fungal diversity in four different deep-sea sediments from Okinawa Trough using high-throughput Illumina sequencing of the nuclear ribosomal internal transcribed spacer-1 (ITS1). A total of 40,297 fungal ITS1 sequences clustered into 420 operational taxonomic units (OTUs) with 97% sequence similarity and 170 taxa were recovered from these sediments. Most ITS1 sequences (78%) belonged to the phylum Ascomycota, followed by Basidiomycota (17.3%), Zygomycota (1.5%) and Chytridiomycota (0.8%), and a small proportion (2.4%) belonged to unassigned fungal phyla. Compared with previous studies on fungal diversity of sediments from deep-sea environments by culture-dependent approach and clone library analysis, the present result suggested that Illumina sequencing had been dramatically accelerating the discovery of fungal community of deep-sea sediments. Furthermore, our results revealed that Sordariomycetes was the most diverse and abundant fungal class in this study, challenging the traditional view that the diversity of Sordariomycetes phylotypes was low in the deep-sea environments. In addition, more than 12 taxa accounted for 21.5% sequences were found to be rarely reported as deep-sea fungi, suggesting the deep-sea sediments from Okinawa Trough harbored a plethora of different fungal communities compared with other deep-sea environments. To our knowledge, this study is the first exploration of the fungal diversity in deep-sea sediments from Okinawa Trough using high-throughput Illumina sequencing.

Radioactivity monitoring of the Turkish Black Sea coast as a part of the IAEA model project 'Marine environmental assessment of the Black Sea region' and nuclear techniques for the environmental management of water resources in Turkey

International Nuclear Information System (INIS)

Goktepe, B.G.; Koksal, G.; Gungor, N.; Gungor, E.; Kose, A.; Kucukcezzar, R.; Varinlioglu, A.; Erkol, A.Y.; Karakelle, B.; Osvath, I.; Fowler, S.

2002-01-01

A wide scope Regional Technical Co-operation Project RER/2/003 'Marine environmental assessment of the Black Sea region' is implemented by the International Atomic Energy Agency (IAEA) in the period 1995-2001. This project is initiated in response to the needs of participating Member-States - the six Black Sea coastal countries (Bulgaria, Romania, Ukraine, Russian Federation, Georgia and Turkey) to establish capabilities for reliably assessing radionuclides in the Black Sea environment and applying tracer technique to marine pollution studies. The project has various important aspects: Scientifically; one of the major environmental issue radioactivity pollution is addressed. Technically; laboratory capability for transuranic analysis is being developed. Economically; the reversing the ecological deterioration and developing sustainable uses of the Black Sea and its natural resources is one of the major interest. Politically; responsibility of pollution control and rehabilitation plans of six Black Sea countries are addressed thought various conventions and declarations. Socio-economically; fisheries and tourism sectors are expected to benefit. Highlights from the joint radioactivity monitoring program of the project among six Black Sea countries are outlined. Examples from Turkish monitoring work consists of the routine sampling of sea water, algae, mussels, fish samples and beach sand from the selected stations along the Black Sea coast are presented for illustration. Insights gained from the application of nuclear techniques for the 'Pollution Investigation of the Kucukcekmece Lake' and the 'Marine environmental assessment of the Black Sea region' Model Technical Co-operation Project carried out at the Cekmece Nuclear Research Center supporting by the IAEA are presented. Concluding remarks include the vital importance of protection of the water resources within Eurasian countries and the need for strong cooperation among nuclear research centers

Euphotic zone bacterioplankton sources major sedimentary bacteriohopanepolyols in the Holocene Black Sea

Science.gov (United States)

Blumenberg, Martin; Seifert, Richard; Kasten, Sabine; Bahlmann, Enno; Michaelis, Walter

2009-02-01

Bacteriohopanepolyols (BHPs) are lipid constituents of many bacterial groups. Geohopanoids, the diagenetic products, are therefore ubiquitous in organic matter of the geosphere. To examine the potential of BHPs as environmental markers in marine sediments, we investigated a Holocene sediment core from the Black Sea. The concentrations of BHPs mirror the environmental shift from a well-mixed lake to a stratified marine environment by a strong and gradual increase from low values (˜30 μg g -1 TOC) in the oldest sediments to ˜170 μg g -1 TOC in sediments representing the onset of a permanently anoxic water body at about 7500 years before present (BP). This increase in BHP concentrations was most likely caused by a strong increase in bacterioplanktonic paleoproductivity brought about by several ingressions of Mediterranean Sea waters at the end of the lacustrine stage (˜9500 years BP). δ 15N values coevally decreasing with increasing BHP concentrations may indicate a shift from a phosphorus- to a nitrogen-limited setting supporting growth of N 2-fixing, BHP-producing bacteria. In sediments of the last ˜3000 years BHP concentrations have remained relatively stable at about 50 μg g -1 TOC. The distributions of major BHPs did not change significantly during the shift from lacustrine (or oligohaline) to marine conditions. Tetrafunctionalized BHPs prevailed throughout the entire sediment core, with the common bacteriohopanetetrol and 35-aminobacteriohopanetriol and the rare 35-aminobacteriohopenetriol, so far only known from a purple non-sulfur α-proteobacterium, being the main components. Other BHPs specific to cyanobacteria and pelagic methanotrophic bacteria were also found but only in much smaller amounts. Our results demonstrate that BHPs from microorganisms living in deeper biogeochemical zones of marine water columns are underrepresented or even absent in the sediment compared to the BHPs of bacteria present in the euphotic zone. Obviously, the assemblage of

Drivers, mechanisms and long-term variability of seasonal hypoxia on the Black Sea northwestern shelf – is there any recovery after eutrophication?

Directory of Open Access Journals (Sweden)

A. Capet

2013-06-01

Full Text Available The Black Sea northwestern shelf (NWS is a shallow eutrophic area in which the seasonal stratification of the water column isolates the bottom waters from the atmosphere. This prevents ventilation from counterbalancing the large consumption of oxygen due to respiration in the bottom waters and in the sediments, and sets the stage for the development of seasonal hypoxia. A three-dimensional (3-D coupled physical–biogeochemical model is used to investigate the dynamics of bottom hypoxia in the Black Sea NWS, first at seasonal and then at interannual scales (1981–2009, and to differentiate its driving factors (climatic versus eutrophication. Model skills are evaluated by a quantitative comparison of the model results to 14 123 in situ oxygen measurements available in the NOAA World Ocean and the Black Sea Commission databases, using different error metrics. This validation exercise shows that the model is able to represent the seasonal and interannual variability of the oxygen concentration and of the occurrence of hypoxia, as well as the spatial distribution of oxygen-depleted waters. During the period 1981–2009, each year exhibits seasonal bottom hypoxia at the end of summer. This phenomenon essentially covers the northern part of the NWS – which receives large inputs of nutrients from the Danube, Dniester and Dnieper rivers – and extends, during the years of severe hypoxia, towards the Romanian bay of Constanta. An index H which merges the aspects of the spatial and temporal extension of the hypoxic event is proposed to quantify, for each year, the intensity of hypoxia as an environmental stressor. In order to explain the interannual variability of H and to disentangle its drivers, we analyze the long time series of model results by means of a stepwise multiple linear regression. This statistical model gives a general relationship that links the intensity of hypoxia to eutrophication and climate-related variables. A total of 82% of the

On Multidisciplinary Investigations of Dangerous Natural Phenomena in the Azov–Black Sea Basin

Directory of Open Access Journals (Sweden)

V.N. Belokopytov

2017-06-01

Full Text Available Certain results of investigating dangerous phenomena and potential natural disasters in the Azov–Black Sea basin are represented. The decrease of storm activity in the Black Sea observed in the end of the XX century is due to diminution of total amount and intensity of the passing cyclones. According to long-term tendencies of the North Atlantic Oscillation and the East Atlantic Oscillation atmosphere indices, future increase of the storm amount in the Black Sea would be expected. The effective sources of storm surges in the Sea of Azov are the atmospheric cyclones spreading with the 20–40 km/h velocity. The decrease of a cyclone movement velocity results in a storm surge intensification in the Gulf of Taganrog and increase of the flooded area in the Don delta. When the Don discharge becomes lower than the threshold value ~1600 m3/s, the wind surge exerts a blocking impact upon the river water that promotes the sea level rise in the branches and the delta lowland. The highest potential tsunami hazard for the Black Sea northern coast is represented by the earthquake epicenters located in the Crimea – Caucasus seismic zone. Noticeable sea level oscillations can arise in some locations of the Crimea Southern Coast as a result of the trapped waves propagating to the northwest, north and northeast from the seismic centers nearby the southern coast of the sea.

Bacterial and archaeal communities in sediments of the north Chinese marginal seas.

Science.gov (United States)

Liu, Jiwen; Liu, Xiaoshou; Wang, Min; Qiao, Yanlu; Zheng, Yanfen; Zhang, Xiao-Hua

2015-07-01

Microbial communities of the Chinese marginal seas have rarely been reported. Here, bacterial and archaeal community structures and abundance in the surface sediment of four sea areas including the Bohai Sea (BS), North Yellow Sea (NYS), South Yellow Sea (SYS), and the north East China Sea (NECS) were surveyed by 16S ribosomal RNA (rRNA) gene pyrosequencing and quantitative PCR. The results showed that microbial communities of the four geographic areas were distinct from each other at the operational taxonomic unit (OTU) level, whereas the microbial communities of the BS, NYS, and SYS were more similar to each other than to the NECS at higher taxonomic levels. Across all samples, Bacteria were numerically dominant relative to Archaea, and among them, Gammaproteobacteria and Euryarchaeota were predominant in the BS, NYS, and SYS, while Deltaproteobacteria and Thaumarchaeota were prevalent in the NECS. The most abundant bacterial genera were putative sulfur oxidizer and sulfate reducer, suggesting that sulfur cycle processes might prevail in these areas, and the high abundance of dsrB (10(7)-10(8) copies g(-1)) in all sites verified the dominance of sulfate reducer in the north Chinese marginal seas. The differences in sediment sources among the sampling areas were potential explanations for the observed microbial community variations. Furthermore, temperature and dissolved oxygen of bottom water were significant environmental factors in determining both bacterial and archaeal communities, whereas chlorophyll a in sediment was significant only in structuring archaeal community. This study presented an outline of benthic microbial communities and provided insights into understanding the biogeochemical cycles in sediments of the north Chinese marginal seas.

Presence of the Striped Seabream (Lithognathus mormyrus L., 1758 in the Black Sea

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Mehmet AYDIN

2017-11-01

Full Text Available It is known that Mediterranean demersal species reach to the Black Sea through the Turkish Straits System and adapt to this nearly landlocked environment. In this article, the existence of Mediterranean originated striped seabream (Lithognathus mormyrus L., 1758 in the Black Sea is studied. In this study, 25 individuals were sampled in the Middle Black Sea region (Ordu – Fatsa by trammel nets. The minimum and maximum lengths of the sampled species were measured as 16 cm and 20.1 cm respectively, while the length-weight relationship can be given by the equation, W=0.0711L2.3981 (R² = 0.8171.

Quantitative estimation of Holocene surface salinity variation in the Black Sea using dinoflagellate cyst process length

DEFF Research Database (Denmark)

Mertens, Kenneth Neil; Bradley, Lee R.; Takano, Yoshihito

2012-01-01

Reconstruction of salinity in the Holocene Black Sea has been an ongoing debate over the past four decades. Here we calibrate summer surface water salinity in the Black Sea, Sea of Azov and Caspian Sea with the process length of the dinoflagellate cyst Lingulodinium machaerophorum. We then apply ...

Geomorphological condition and sea bottom sediment characteristics of Sebagin coast for NPP site evaluation in South Bangka

International Nuclear Information System (INIS)

Yuliastuti; Heni Susiati; Yarianto Sugeng Budi Susilo

2015-01-01

Study on geomorphological condition and sea bottom sediment in the coastal area of Sebagin, South Bangka Regency, Bangka Belitung Province has been performed. Geomorphological of the seabed was valuable to identify geological structures that exist on the seabed layers. Whereas, sediments seabed characteristics was useful to provide portrait of seabed layer due to the stability of NPP site concerning the seismic aspect and the determination of water intake position. The objective of the study was to evaluate geomorphological condition and sea bed sediment characteristics in the South Bangka sea. Methodology used for evaluating geomorphological of the sea bed were Multi Beam Echo Sounder (MBES) and Single Beam Echo Sounder (SBES), while for sea bottom sediment characteristics, high resolution seismic reflection using SBP together with sediment sample analysis were used. The result of the study showed that the study area was a shallow water sea with a depth range of 1-59 m. Geomorphological profile of the sea bed tend to be irregular and based on the seismic interpretation, there were no fault exists. Result analysis on the sea bottom sediment showed that clay distribution dominated the study area. (author)

18O/16O ratios of the pore water of Baltic Sea sediments

International Nuclear Information System (INIS)

Foerstel, H.

1983-01-01

Two cores of Baltic Sea sediment were collected in 1975. The 18 O/ 16 O ratio of the water enclosed in the sediment (pore water) was measured after the separation of the liquid from the solid phase. The results may support the discussion about the history of the Baltic Sea. At the top of the core the 18 O/ 16 O ratio of the water represents the oxygen isotope composition of the sea water above. Towards the deeper parts of the sediment, independently of the salt content, the 18 O/ 16 O ratio decreases towards values observed in the precipitation of the surrounding land areas. (author)

Rare earth element exchange through the Bosporus : The Black Sea as a net source of REEs to the Mediterranean Sea

NARCIS (Netherlands)

Schijf, Johan; Baar, Hein J.W. de; German, C.R.

1995-01-01

The Bosporus is the only source of seawater to the Black Sea and helps to maintain the basin-wide salinity gradient that caused the Black Sea to become the largest permanently anoxic basin in the world, some 3000 years ago. Concentrations of dissolved rare earth elements (REEs) in each of the three

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.

Estimates of tsunami damage for Russian coast of the Black Sea

Science.gov (United States)

Zaytsev, Andrey; Yalciner, Ahmet; Pelinovsky, Efim

2010-05-01

The historic database of tsunamis in the Black Sea contains 20 - 30 events with different level of validity, and at least six events occurred in 20th century. Numerical modeling of the last historic events is performed in the framework of shallow-water theory with use of code NAMI-DANCE. The computed tide-gauge records in Russian coastal locations are in good agreement with instrumental data for the 1939 and 1966 tsunamis. The tsunami of the landslide origin occurred in Sochi in 1970 is modeled in the framework of the two-layer model realized in TUNAMI. Also, some hypothetic tsunamis generated in the open part of the Black Sea are computed and the distribution of the tsunami height along the Russian and Turkish coast ais found. In particular, the tsunami amplification near Sochi is highest to compare with other coastal locations on the Russian coast of Black Sea.

Black Sea and Caspian Sea, Symposium II, Constanta, Romania

Science.gov (United States)

2007-05-01

Great, the Bronze Horseman . You may have heard me quote this before, but Pushkin in his poem “Th e Bronze Horseman ,” asks rhe- torically “Whither dost...mile down the embankment from the Bronze Horseman in front of the Admiralty Building in Petersburg. It commemorates the Czarist Foreign Minister...need for a coordinated approach to broader political developments in the Black and Caspian Sea regions. Th e December 21, 2006 death of

Caesium-137 distribution, inventories and accumulation history in the Baltic Sea sediments.

Science.gov (United States)

Zaborska, Agata; Winogradow, Aleksandra; Pempkowiak, Janusz

2014-01-01

The Baltic Sea is susceptible to pollution by hazardous substances due to limited water exchange, shallowness, and the large catchment area. Radionuclides, particularly (137)Cs, are one of the most hazardous anthropogenic substances present in the Baltic environment. This study was conducted to present (137)Cs present contamination that should further be a subject of reliable monitoring when the new Nuclear Power Plant is put into operation in the northern Poland. The sea-wide, up to date distribution of (137)Cs activities and inventories in the Baltic Sea bottom sediments are presented. The (137)Cs activity concentrations were measured in 30 cm long sediment cores collected at 22 sampling stations. Sediment accumulation rates were quantified by (210)Pb geochronology to follow the history of (137)Cs accumulation. The (137)Cs inventories and fluxes were calculated. Most of the Baltic Sea sediments accumulated (137)Cs in the range from 750 to 2675 Bq m(-2). The Bothnian Bay is severely contaminated by (137)Cs with inventories up to 95,191 Bq m(-2). This region is moreover characterized by extremely large patchiness of (137)Cs inventories. The (137)Cs annual fluxes are highest at the two stations located at the Bothnian Bay (342 Bq m(-2) and 527 Bq m(-2)) due to large Chernobyl (137)Cs contamination of that region and high sediment accumulation rates. When these stations are excluded, the recent, annual mean value of (137)Cs load to the Baltic Sea deposits is 38 ± 22 Bq m(-2). The distribution of radio-caesium inventories over the Baltic Sea nowadays reflects the pattern of Chernobyl contamination. The radio-caesium deposited in surface sediments is not permanently buried, but may be resuspended and redeposited by currents, bioturbation or anthropogenic activities. Copyright © 2013 Elsevier Ltd. All rights reserved.

Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment

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V. Brüchert

2018-01-01

Full Text Available The Siberian Arctic Sea shelf and slope is a key region for the degradation of terrestrial organic material transported from the organic-carbon-rich permafrost regions of Siberia. We report on sediment carbon mineralization rates based on O2 microelectrode profiling; intact sediment core incubations; 35S-sulfate tracer experiments; pore-water dissolved inorganic carbon (DIC; δ13CDIC; and iron, manganese, and ammonium concentrations from 20 shelf and slope stations. This data set provides a spatial overview of sediment carbon mineralization rates and pathways over large parts of the outer Laptev and East Siberian Arctic shelf and slope and allows us to assess degradation rates and efficiency of carbon burial in these sediments. Rates of oxygen uptake and iron and manganese reduction were comparable to temperate shelf and slope environments, but bacterial sulfate reduction rates were comparatively low. In the topmost 50 cm of sediment, aerobic carbon mineralization dominated degradation and comprised on average 84 % of the depth-integrated carbon mineralization. Oxygen uptake rates and anaerobic carbon mineralization rates were higher in the eastern East Siberian Sea shelf compared to the Laptev Sea shelf. DIC ∕ NH4+ ratios in pore waters and the stable carbon isotope composition of remineralized DIC indicated that the degraded organic matter on the Siberian shelf and slope was a mixture of marine and terrestrial organic matter. Based on dual end-member calculations, the terrestrial organic carbon contribution varied between 32 and 36 %, with a higher contribution in the Laptev Sea than in the East Siberian Sea. Extrapolation of the measured degradation rates using isotope end-member apportionment over the outer shelf of the Laptev and East Siberian seas suggests that about 16 Tg C yr−1 is respired in the outer shelf seafloor sediment. Of the organic matter buried below the oxygen penetration depth, between 0.6 and 1.3�

Linkages between the spatial toxicity of sediments and sediment dynamics in the Yangtze River Estuary and neighboring East China Sea.

Science.gov (United States)

Gao, Jinjuan; Shi, Huahong; Dai, Zhijun; Mei, Xuefei; Zong, Haibo; Yang, Hongwei; Hu, Lingling; Li, Shushi

2018-02-01

Anthropogenic activities are driving an increase in sediment contamination in coastal areas. This poses significant challenges for the management of estuarine ecosystems and their adjacent seas worldwide. However, few studies have been conducted on how dynamic mechanisms affect the sediment toxicity in the estuarine environment. This study was designed to investigate the linkages between sediment toxicity and hydrodynamics in the Yangtze River Estuary (YRE) area. High sediment toxicity was found in the Yangtze River mouth (Region I), the depocenter of the Yangtze River Delta (Region II), and the southeastern area of the adjacent sea (Region III), while low sediment toxicity was found in the northeastern offshore region (Region IV). A spatial comparison analysis and regression model indicated that the distributed pattern of sediment toxicity was likely related to hydrodynamics and circumfluence in the East China Sea (ECS) shelf. Specifically, high sediment toxicity in Region I may be affected by the Yangtze River Pump (YRP) and the low hydrodynamics there, and high toxicity in Region II can be influenced by the low sediment dynamics and fine sediment in the depocenter. The high sediment toxicity in Region III might be related to the combination of the YRP and Taiwan Warm Current, while the low toxicity in Region IV may be influenced by the local coarse-grained relict sand with strong sediment dynamics there. The present research results further suggest that it is necessary to link hydrodynamics and the spatial behavior of sediment and sediment-derived pollutants when assessing the pollution status of estuarine environments, especially for those mega-estuaries and their neighboring ocean environments with complex waves, tides and ocean currents. Copyright © 2017 Elsevier Ltd. All rights reserved.

The behavior of scavenged isotopes in marine anoxic environments: 210Pb and 210Po in the water column of the Black Sea

International Nuclear Information System (INIS)

Wei, C.L.; Murray, J.W.

1994-01-01

Vertical profiles of dissolved and particulate 210 Pb and 210 Po were determined at two stations in the Black Sea in June 1988. Vertical fluxes of 210 Pb and 210 Po were also measured in the upper 150 m, using floating sediment traps. The fractionation of 210 Pb between dissolved and particulate phases in the Black Sea is strongly influenced by the redox conditions in the water column. Dissolved 210 Pb dominates in the oxic zone, while particulate 210 Pb is the major form in the deep sulfide-rich anoxic zone. The distribution of 210 Pb across the suboxic zone appears to be mainly controlled by redox cycling of manganese and iron. In the sulfide-rich layer coprecipitation of lead with iron sulfide is probably the dominant scavenging mechanism. A simple scavenging model was used to calculate the residence times of dissolved and particulate 210 Pb in the oxic, suboxic, and anoxic zones. The residence times of dissolved 210 Pb relative to scavenging by particles are 0.5-1, 2-3, and 3.5 years in the oxic, suboxic, and anoxic layers, respectively. The corresponding residence times of particulate 210 Pb relative to particle removal processes in the same layers are 0.1, 1.5-2.5, and 8.5 years, respectively. A particle settling velocity of about 40 m y -1 was derived from the 210 Pb/ 226 Ra disequilibrium in the deep Black Sea. The relatively short residence times of 210 Pb support the hypothesis that anoxic basins are important sites for boundary scavenging of 210 Pb. The 210 Po profiles indicate that biological rather than inorganic particles are the major carrier phases for Po in the Black sea. Based on the magnitude of distribution coefficients, the relative partitioning of Pb, Po, and Th to particles found in the oxic and anoxic layers of the Black Sea are Po > Th > Pb and Po = Pb > Th, respectively. Colloidal phases may be important for the scavenging of these radionuclides

Rn 222 in the Black Sea waters

International Nuclear Information System (INIS)

Arbuzova, A.P.; Batrakov, G.F.; Eremeev, V.N.; Zemlyanoj, A.D.; Ivanova, T.M.

1988-01-01

Results of Rn 222 concentration measurements in the Black Sea waters obtained in the summer of 1986 during the expedition of the Akademik Vernadskij research ship are presented. It is ascertained that the intensity of vertical turbulent exchange produces the main effect on Rn 222 distribution in the sea surface waters. The vertical distribution in a 200 m layer is characterized by the growth of concentration with depth, which is caused by the presence of Ra 226 increased concentration region, that coincides with the boundary layer between oxygen and hydrogen sulfide

Tourism-Environment Impact Relationship on the Romanian Black Sea Coast

Directory of Open Access Journals (Sweden)

Anca Cristina Stanciu

2016-01-01

The present paper aims to identify the key features which may intervene in the tourist developmenton the Romanian Black Sea Coast perceived as limits, constraints and bottlenecks on the basis ofwhich tourism management decisions have to be taken. In this respect, the study will take intoconsideration the concept of tourism carrying capacity, meaning the maximum acceptable level oftourist development in an area and intend to stress out the main steps to implement this instrumentto be used in the analysis of tourist potential but also as a policy tool in a strategy of touristdevelopment for the Romanian Black Sea coast.

Spectroscopic studies of humic acids from subsurface sediment samples collected across the Aegean Sea

Directory of Open Access Journals (Sweden)

F. SAKELLARIADOU

2006-12-01

Full Text Available Natural humic acids are biogenic, structurally complex and heterogeneous, refractory, acidic, yellow-to black-coloured organic polyelectrolytes of relatively high molecular weight. They occur in all soils, sediments, fresh waters, and seawaters. Humic acids represent the largest portion of nonliving soil organic matter. In the present paper, humic substances were isolated from marine subsurface sediment samples collected across the Aegean sea (in Greece and especially from a marine area extending northwards of the Samothraki plateau towards the north-eastern part of the island of Crete. In a following step, humic preparations were studied using infrared and fluorescence spectroscopy (emission, excitation and synchronous-scan excitation spectra were obtained. The infrared spectra suggested functional chemical groups such as as OH-, C-H aliphatic, C=C, C=O/COO-, salts of carboxylic acids, and also, in some cases, silicate anions or C-O from alcohols, esters and ethers. Fluorescence emission, excitation and synchronous scan excitation provided some valuable information concerning a probable origin (marine and/or terrestrial for the isolated humics.

PAHs concentration and toxicity in organic solvent extracts of atmospheric particulate matter and sea sediments.

Science.gov (United States)

Ozaki, Noriatsu; Takeuchi, Shin-ya; Kojima, Keisuke; Kindaichi, Tomonori; Komatsu, Toshiko; Fukushima, Takehiko

2012-01-01

The concentration of polycyclic aromatic hydrocarbons (PAHs) and the toxicity to marine bacteria (Vibrio fischeri) were measured for the organic solvent extracts of sea sediments collected from an urban watershed area (Hiroshima Bay) of Japan and compared with the concentrations and toxicity of atmospheric particulate matter (PM). In atmospheric PM, the PAHs concentration was highest in fine particulate matter (FPM) collected during cold seasons. The concentrations of sea sediments were 0.01-0.001 times those of atmospheric PM. 1/EC50 was 1-10 L g(-1) PM for atmospheric PM and 0.1-1 L g(-1) dry solids for sea sediments. These results imply that toxic substances from atmospheric PM are diluted several tens or hundreds of times in sea sediments. The ratio of the 1/EC50 to PAHs concentration ((1/EC50)/16PAHs) was stable for all sea sediments (0.1-1 L μg(-1) 16PAHs) and was the same order of magnitude as that of FPM and coarse particulate matter (CPM). The ratio of sediments collected from the west was more similar to that of CPM while that from the east was more similar to FPM, possibly because of hydraulic differences among water bodies. The PAHs concentration pattern analyses (principal component analysis and isomer ratio analysis) were conducted and the results showed that the PAHs pattern in sea sediments was quite different to that of FPM and CPM. Comparison with previously conducted PAHs analyses suggested that biomass burning residues comprised a major portion of these other sources.

Biodiversity of the macrozoobenthos in some protected marine areas along Bulgarian Black Sea coast

Directory of Open Access Journals (Sweden)

E. Petrova

2017-12-01

Full Text Available Abstract. The aim of this paper is to establish the biodiversity status of the macrozoobenthos in some protected marine areas (NATURA 2000 along the Bulgarian Black Sea coast. The observation stations in the period 2010-2012 were within the frames of the following habitats: 1160 – Large shallow inlets and bays; 1110 – Sandbanks, slightly covered by seawater and Sublittoral mussel banks on sediment. In general, the data shows steady state compared to the 1980s, except for the area near Kamchia River, characterized by low biodiversity due to water pollution from the river inflow (with contaminants from agricultural and industrial sources in the upper river stream and less salinity leading to marine mussel species reduction. In the border area, near the Emona zone, the black mussel catches varied between 160-600 kg in 2005, while only single specimens were detected in 2013. In the same field, the yield of Rapana venosa was within the limits of 5-40 kg in 2005 and between 80-160 kg in 2013. The established variability showed a dynamic balance between Mytilus galloprovicialis and Rapana venosa that pose a challenge for future stock of the black mussel and point the need of regular monitoring.

Supernova-produced radionuclides in deep-sea sediments measured with AMS

International Nuclear Information System (INIS)

Feige, J.

2014-01-01

This thesis is dedicated to computational micromagnetics, where several new numerical methods are In this work a set of long-lived radionuclides is measured to detect supernova-traces presumably deposited on Earth 2-3 Myr ago. Approximately 100 samples of four deep-sea sediment cores (Indian Ocean) were analyzed for 26 Al, 53Mn, and 60 Fe with accelerator mass spectrometry (AMS). Additionally, 10 Be was measured to confirm the existing paleomagnetic chronology of the sediments. A signal of extraterrestrial 60 Fe, which is not produced in-situ on Earth, was detected in a time period of 1.7-3.2 Myr in the sediments used for this work. 60 Fe/ 26 Al ratios were used to calculate limits on theoretical nucleosynthesis models. A supernova-signature of 26 Al is hidden behind a terrestrial background. The measured 26 Al/ 10 Be ratios indicate, that the major source of 26 Al detected in the sediments is of atmospheric origin. Because of the extraordinarily good depth profile for the deep-sea sediments from the measured 26 Al data, this radionuclide was used for dating. (author) [de

High occurrence of Bathyarchaeota (MCG) in the deep-sea sediments of South China Sea quantified using newly designed PCR primers.

Science.gov (United States)

Yu, Tiantian; Liang, Qianyong; Niu, Mingyang; Wang, Fengping

2017-08-01

The archaeal phylum Bathyarchaeota, which is composed of a large number of diverse lineages, is widespread and abundant in marine sediments. Environmental factors that control the distribution, abundance and evolution of this largely diversified archaeal phylum are currently unclear. In this study, a new pair of specific primers that target the major marine subgroups of bathyarchaeotal 16S rRNA genes was designed and evaluated to investigate the distribution and abundance of Bathyarchaeota in marine sediments. The abundance of Bathyarchaeota along two sediment cores from the deep-sea sediments of South China Sea (SCS, each from the Dongsha and Shenhu area) was determined. A strong correlation was found between the bathyarchaeotal abundance and the content of total organic carbon (TOC), suggesting an important role of Bathyarchaeota in organic matter remineralisation in the sediments of SCS. Furthermore, diversity analysis revealed that subgroups Bathy-2, Bathy-8 and Bathy-10 were dominant bathyarchaeotal members of the deep-sea sediments in the SCS. Bathy-8 was found predominantly within the reducing and deeper sediment layers, while Bathy-10 occurred preferentially in the oxidizing and shallower sediment layers. Our study lays a foundation for the further understanding of the ecological functions and niche differentiation of the important but not well-understood sedimentary archaeal group. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Radiocarbon dating of bottom sediments of the Red Sea

International Nuclear Information System (INIS)

Kuptsov, V.M.; Palkina, A.M.

1986-01-01

Results of radiocarbon dating of 23 cores (81 definitions) sampled in the Red Sea rifton at 18 deg N are presented. Dating encompasses all major tectonic structures: the upper and the lower tectonic steps, saline scarp, axial zone. For sediments of the upper tectonic step the normal course of sedimentogenesis is detected, in all other structures with a strongly dissected topography redeposition and nonaccumulation of sediments are widely developed. In Holocene the rate of sediment accumulation is 1.5-2 times lower than that in the late Wurm

90Sr and 137Cs in the Black Sea after the Chernobyl NPP accident: inventories, balance and tracer applications

International Nuclear Information System (INIS)

Egorov, V.N.; Povinec, P.P.; Polikarpov, G.G.; Stokozov, N.A.; Gulin, S.B.; Kulebakina, L.G.; Osvath, I.

1999-01-01

The paper summarizes studies of the distributions of 90 Sr and 137 Cs in the water and sediments of the Black Sea carried out during a 10-year period following the 1986 accident at the Chernobyl Nuclear Power Plant. Its goal is to assess the temporal evolution of radionuclide inventories and balances and to evaluate the mixing of water masses and the sedimentation processes using man-made radionuclides as tracers. Using mathematical models and field data, mixing time-scales of 5, 16 and 24 years have been estimated, respectively, for the water layers of depths 0-50, 0-100 and 0-200 m. For the Central Basin the ventilation time of the lower pycnocline is estimated at 15-25 years. 137 Cs has been used to date shelf and deep-basin sediments, providing the history of chemical and radioactive pollution and of eutrophication during the past 50 years. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Adsorption - desorption equilibria of some radionuclides in sediment - sea water system

International Nuclear Information System (INIS)

El-Assy, N.B.; Fattah, A.T.A.; El-Shinawy, R.M.K.; Essa, M.W.A.

1991-01-01

Chemical and physical properties of Suez Canal bottom sediments (SCBS) and sea water at port Tawfeek area, the south entrance of Suez canal, have been studied. The SCBS was separated into its size fractions (natural sediment, sand, silt and clay). These different sediment fractions were allowed to be in equilibrium with 89 Sr, 60 Co and 134 Cs solutions. Desorption studies were carried out on these contaminated sediments. (author) 16 refs.; 1 fig.; 1 tab

REGIONAL BLACK SEA ARCHITECTURE AND CONSEQUENCES FOR THE REGIONAL COOPERATION FRAMEWORK

Directory of Open Access Journals (Sweden)

Alina Homorozean

2010-12-01

Full Text Available Sometimes considered an asset, other times a liability, the Black Sea started recently to be regarded as a region. However, the Black Sea Region lacks a common vision, often due to the complicated and often inefficient nexus of regional cooperation initiatives. Following the logic of finding regional solutions for regional problems, this paper aims to assess existing institutional and regional initiatives, reflecting on the implications for the success of Black Sea regionalism in creating patterns of sustained and sustainable development and a high degree of actors' involvement.This paper concentrates on two complementary research questions: What is the regional order in the BSR and what does it imply for its future? What is the current contribution of the most significant cooperation initiatives and what are the consequences for regional institutionalism? For the purpose of this paper, I draw on best-practices from other two regions: the Northern Dimension and South- East Asia. Through a comparative perspective, I suggest an analysis of the most important initiatives: BSEC, CDC, Black Sea Synergy, Eastern Partnership, Baku Initiative and the BSF. This paper argues that a possible strategic solution for successful policy development lies in the creation of an integrated regional cooperation package, functioning on the principles of multi-speed and multi-dimensional cooperation in several policy fields, in a context in which the BSR seems to be caught between two paradigms: a European and a Russian-oriented one.

Aliphatic hydrocarbons in surface sediments from South China Sea off Kuching Division, Sarawak

International Nuclear Information System (INIS)

Hafidz Yusoff; Zaini Assim; Samsur Mohamad

2012-01-01

Eighteen surface sediment samples collected from South China Sea off Kuching Division, Sarawak were analyzed for aliphatic hydrocarbons. These hydrocarbons were recovered from sediment by Soxhlet extraction method and then analyzed using gas chromatography equipped with mass spectrometer (GC/ MS). Total concentrations of aliphatic hydrocarbons in surface sediments from South China Sea off Kuching division are ranged from 35.6 μg/ g to 1466.1 μg/ g dry weights. The sediments collected from Bako Bay, Kuching showed high concentrations of total aliphatic hydrocarbons. Several molecular indices were used to predict the predominant sources of hydrocarbons. Carbon preference index (CPI) value revealed widespread anthropogenic input in this study area (CPI= 0 to 4.1). The ratio of C 31 / C 19 and C 29 / C 31 indicated that major input of aliphatic hydrocarbon mostly transfer by lateral input to the marine environment than atmospheric movements. Generally, the concentrations of aliphatic hydrocarbons in sediment from South China Sea off Kuching division are generally higher compare to other area in the world. (author)

Sedimentology and geochemistry of surface sediments, outer continental shelf, southern Bering Sea

Science.gov (United States)

Gardner, J.V.; Dean, W.E.; Vallier, T.L.

1980-01-01

Present-day sediment dynamics, combined with lowerings of sea level during the Pleistocene, have created a mixture of sediments on the outer continental shelf of the southern Bering Sea that was derived from the Alaskan Mainland, the Aleutian Islands, and the Pribilof ridge. Concentrations of finer-grained, higher-organic sediments in the region of the St. George basin have further modified regional distribution patterns of sediment composition. Q-mode factor analysis of 58 variables related to sediment size and composition - including content of major, minor, and trace elements, heavy and light minerals, and clay minerals - reveals three dominant associations of sediment: 1. (1) The most significant contribution, forming a coarse-grained sediment scattered over most of the shelf consists of felsic sediment derived from the generally quartz-rich rocks of the Alaskan mainland. This sediment contains relatively high concentrations of Si, Ba, Rb, quartz, garnet, epidote, metamorphic rock fragments, potassium feldspar, and illite. 2. (2) The next most important group, superimposed on the felsic group consists of andesitic sediment derived from the Aleutian Islands. This more mafic sediment contains relatively high concentrations of Na, Ca, Ti, Sr, V, Mn, Cu, Fe, Al, Co, Zn, Y, Yb, Ga, volcanic rock fragments, glass, clinopyroxene, smectite, and vermiculite. 3. (3) A local group of basaltic sediment, derived from rocks of the Pribilof Islands, is a subgroup of the Aleutian andesite group. Accumulation of fine-grained sediment in St. George basin has created a sediment group containing relatively high concentrations of C, S, U, Li, B, Zr, Ga, Hg, silt, and clay. Sediment of the Aleutian andesite group exhibits a strong gradient, or "plume", with concentrations decreasing away from Unimak Pass and toward St. George basin. The absence of present-day currents sufficient to move even clay-size material as well as the presence of Bering submarine canyon between the Aleutian

The Mediterranean and Black Sea fisheries at risk from overexploitation.

Directory of Open Access Journals (Sweden)

Athanassios C Tsikliras

Full Text Available The status of the Mediterranean and Black Sea fisheries was evaluated for the period 1970-2010 on a subarea basis, using various indicators including the temporal variability of total landings, the number of recorded stocks, the mean trophic level of the catch, the fishing-in-balance index and the catch-based method of stock classification. All indicators confirmed that the fisheries resources of the Mediterranean and Black Sea are at risk from overexploitation. The pattern of exploitation and the state of stocks differed among the western (W, central (C and eastern (E Mediterranean subareas and the Black Sea (BS, with the E Mediterranean and BS fisheries being in a worst shape. Indeed, in the E Mediterranean and the BS, total landings, mean trophic level of the catch and fishing-in-balance index were declining, the cumulative percentage of overexploited and collapsed stocks was higher, and the percentage of developing stocks was lower, compared to the W and C Mediterranean. Our results confirm the need for detailed and extensive stock assessments across species that will eventually lead to stocks recovering through conservation and management measures.

Plutonium in intertidal coastal and estuarine sediments in the Northern Irish Sea

International Nuclear Information System (INIS)

Aston, S.R.; Assinder, D.J.; Kelly, M.

1985-01-01

Surface intertidal sediments from 35 sites in the Irish Sea have been analysed for their 238 Pu and sup(239,240)Pu activities, together with an intensive study of plutonium in sediments of the Esk Estuary (NW England). The range of plutonium activities for the whole survey were 0.14-4118 and 1.3-16 026 Bq kg -1 for 238 Pu and sup(239,240)Pu, respectively. The levels of Pu activity, derived from the Sellafield nuclear fuel reprocessing effluents, in sediments are controlled by lithological factors and the influence of transport and post-depositional processes. Grain size distribution is particularly important, the major part of plutonium activity being in the mud fraction of all sediments. The data suggest that over the Irish Sea coastline, dynamic mixing of sediment grains by reworking and resuspension and/or by dispersion in tidal currents are important in determining plutonium distributions. The exponential decrease in sediment plutonium activities away from the Sellafield source is attributed to the progressive mixing with older contaminated and uncontaminated sediments. (author)

Productivity, facies and stable-isotope records of OAE2 (Cenomanian - Turonian) in the NW European epicontinental sea: from the English Chalk to North Sea black shales

Science.gov (United States)

Jarvis, Ian; Olde, Kate; Trabucho-Alexandre, João; Gröcke, Darren

2013-04-01

The Late Cretaceous (100.5 - 66.0 Ma) provides perhaps the best example of how the Earth System may function under long-term extreme greenhouse conditions. Rapidly rising global temperatures indicate that we are heading 'back to the Cretaceous' within a few hundred years, so a better understanding of this time interval is essential. The beginning of the Late Cretaceous was characterized by a period of rapidly rising eustatic sea level, the Cenomanian transgression, which flooded continental margins and established large areas of new epicontinental sea that accumulated thick sequences of pelagic and hemipelagic carbonate (chalk). Highest global temperatures were reached during the early part of the Turonian Stage (93.9 - 89.8 Ma). This period of dramatic palaeoenvironmental change was accompanied by one the largest perturbations of the global carbon cycle in the Mesozoic: Oceanic Anoxic Event 2 (OAE2), which was characterized by a 500 kyr episode of oceanic anoxia, widespread black shale deposition, biotic turnover, and a large global positive carbon stable-isotope excursion (2 - 6 ‰ ∂13C) recorded in marine carbonates and both marine and terrestrial organic matter. The Cenomanian-Turonian boundary interval exposed at Eastbourne, southern England, has become established as a European reference section for OAE2. Here, and elsewhere in Europe, the base of the ∂13C excursion is coincident with a marked facies change from rhythmically bedded grey chalks and marls, to a >8 m thick package of dark greenish-grey marl - the Plenus Marl. The termination of OAE2 occurs 6 m above, in a package of pale-yellow-weathering nodular chalks with prominent marl seams. Sediments are organic lean (10 wt%. The onshore equivalent in eastern England (the Black Band) is similarly organic-rich, as are comparable sections in northern Germany (e.g. Wunstorf), indicating likely fully anoxic episodes within some NW European basins. The exact stratigraphic equivalence between the onshore

The European Eel Anguilla anguilla (Pisces, Anguillidae. Native or Alien in the Black Sea?

Directory of Open Access Journals (Sweden)

Apostolos I. Apostolou

2013-12-01

Full Text Available In 2006 the Scientific, Technical and Economic Committee for Fisheries (STEFC of EU suggested the Black Sea region should be excluded from the list of natural areas, where the European eel (Anguilla anguilla is distributed. The basic conception of this idea was that the eels caught in the Black Sea region represent escaped specimens from fish farming in some Danubian countries. This article illustrates an effort to be given an indirect answer on the question if Black Sea is the end of natural distribution of European eel. The species is present but never been abundant in the region and do not represent an object of commercial fishing.

Molecular taxonomy study of representatives of the genus Gobius inhabiting coastal waters of Black Sea region

Directory of Open Access Journals (Sweden)

Feriha Tserkova

2016-12-01

Full Text Available According to their origin the Black Sea gobies can be divided to Ponto-Caspian relicts and Mediterranean immigrants. The increase of species diversity in the Black Sea is a consequence of Mediterranean immigrants. The present study investigated the variability in Cytochrome b sequences isolated from two former Mediterranean immigrant species: Gobius niger and Zosterisessor ophiocephalus. The annotated at NCBI Cyt b sequences of the species were also used to extend the reach of the study. The analyses demonstrated that Black Sea inhabited by four haplotypes of G. niger. Four other haplotypes were found in sequences of Mediterranean black gobies. In the Black Sea haplotype, 6 is predominant and 83.5% of all G. niger representatives belong to it. Three other haplotypes (H_1; H_7 and H_8 were found to form isolated populations. The Tajima D-test indicated that in the Black Sea G. niger in a stage of expansion and significant evolutionary pressure according to data from Maximum Composite Likelihood model of Tamura-Nei, which can explain the accumulation of mutation and appearance of new haplotypes. Unlike G. niger, Z. ophiocephalus populations are shrinking according to Tajima D-test and only one haplotype is still surviving in isolated locations in the Black Sea. These data are in agreement with previous reports of other authors which alarmed that the grass goby is a critically endangered species close to extinction.

Evaluating potential conservation conflicts between two listed species: sea otters and black abalone.

Science.gov (United States)

Raimondi, Peter; Jurgens, Laura J; Tinker, M Tim

2015-11-01

Population consequences of endangered species interacting as predators and prey have been considered theoretically and legally, but rarely investigated in the field. We examined relationships between spatially variable populations of a predator, the California sea otter, Enhydra lutris nereis, and a prey species, the black abalone, Haliotis cracherodii. Both species are federally listed under the Endangered Species Act and co-occur along the coast of California. We compared the local abundance and habitat distribution of black abalone at 12 sites with varying densities of sea otters. All of the populations of abalone we examined were in the geographic area currently unaffected by withering disease, which has decimated populations south of the study area. Surprisingly, our findings indicate that sea otter density is positively associated with increased black abalone density. The presence of sea otters also correlated with a shift in black abalone to habitat conferring greater refuge, which could decrease illegal human harvest. These results highlight the need for a multi-species approach to conservation management of the two species, and demonstrate the importance of using field-collected data rather than simple trophic assumptions to understand relationships between jointly vulnerable predator and prey populations.

Postglacial floodings of the Marmara Sea: molluscs and sediments tell the story

Science.gov (United States)

Büyükmeriç, Yeşim

2016-08-01

The early Holocene marine flooding of the Black Sea has been the subject of intense scientific debate since the "Noah's Flood" hypothesis was proposed in the late 1990s. The chronology of the flooding is not straightforward because the connection between the Black Sea and the Mediterranean Sea involves the intermediate Marmara Sea Basin via two sills (Dardanelles and Bosphorus). This study explores the chronology of late Pleistocene-Holocene flooding by examining sedimentary facies and molluscs from 24 gravity cores spanning shelf to slope settings in the southern Marmara Sea Basin. A late Pleistocene Ponto-Caspian (Neoeuxinian) mollusc association is found in 12 of the cores, comprising 14 mollusc species and dominated by brackish (oligohaline-lower mesohaline) endemic taxa (dreissenids, hydrobiids). The Neoeuxinian association is replaced by a Turritella- Corbula association at the onset of the Holocene. The latter is dominated by marine species, several of which are known to thrive under dysoxic conditions in muddy bottoms. This association is common in early Holocene intervals as well as sapropel intervals in younger Holocene strata. It is an indicator of low-salinity outflows from the Black Sea into the Marmara Sea that drive stratification. A marine Mediterranean association (87 species) represents both soft bottom and hard substrate faunas that lived in well-ventilated conditions and upper mesohaline-polyhaline salinities (ca. 25 psu). Shallower areas were occupied by hard substrate taxa and phytopdetritic communities, whereas deeper areas had soft bottom faunas. The middle shelf part of the northern Gemlik Gulf has intervals with irregular and discontinuous sedimentary structures admixed with worn Neoeuxinian and euryhaline Mediterranean faunas. These intervals represent reworking events (slumping) likely related to seismic activity rooted in the North Anatolian Fault system. The core data and faunas indicate an oscillating postglacial sea-level rise and

Residual circulation and suspended sediment transport in the Dutch Wadden Sea

Science.gov (United States)

Duran-Matute, Matias; Sassi, Maximiliano; de Boer, Gerben; Grawë, Ulf; Gerkema, Theo; van Kessel, Thijs; Cronin, Katherine

2014-05-01

The Dutch Wadden Sea (DWS), situated between continental Europe and the Dutch Wadden Islands, is a semi enclosed basin connected to the North Sea by a series of tidal inlets and composed mainly of tidal flats and sea gullies. The DWS is of high ecological importance due to its biodiversity and has been declared a World Heritage site by UNESCO. It is a dynamic area subject to regional relative sea level rise due to global sea level rise, postglacial rebound and gas exploitation. For intertidal areas to continue to serve as feeding ground for migratory birds, a net import of sediment is required. Observations are crucial but provide only scarce information in space and time. Hence, to estimate the net influx of suspended sediment into the DWS, realistic high resolution three-dimensional numerical simulations have been carried out using the General Estuarine Transport Model (GETM). The hydrodynamics are mainly governed by the tides, the fresh water discharge from several sluices into the DWS and wind variability. It is expected that the transport of suspended particulate matter (SPM) is governed by the same factors, too, in combination with sediment sink and source terms. For validation, the results are compared against different observational data sets, such as tidal gauges, temperature and salinity at a fixed station, and the volumetric flux rate through one of the inlets obtained from an acoustic Doppler current profiler (ADCP) attached to a ferry. SPM transport is modeled for four different sediment classes each of which is defined by the critical shear stress and the settling velocity. Results show a clear net import of SPM through one of the inlets, which is in agreement with the observations. First estimates of the total sediment fluxes through the different inlets are presented together with an analysis on their variability and sensibility to the external forcing. Of particular importance is the net export of SPM during storms as well as the role of storms on

Depletion of barium and radium-226 in Black Sea surface waters over the past thirty years

International Nuclear Information System (INIS)

Kenison Falkner, K.K.; Edmond, J.M.; O'Neill, D.J.; Todd, J.F.; Moore, W.S.

1991-01-01

The nearly landlocked waters of the Black Sea support a valuable fishery, but are also particularly vulnerable to anthropogenic disturbance. Here we use dissolved barium and radium-226 as tracers, to investigate the biogeochemical health of the sea. Both elements are brought to surface waters by vertical mixing of deeper, enriched waters, and by rivers; these inputs should ordinarily be balanced by outflow of surface waters at the Bosphorus, and by biologically mediated removal of 226 Ra-bearing barite. We show, however, that surface-water inventories have been substantially depleted over the past few decades: recent (1988-89) barium concentrations were 1.6 times lower than in 1958 and 1967. These observations suggest that steady-state cycling of these elements has been perturbed by increased primary productivity, presumably fuelled by nutrients from industry and agricultural runoff, and to a lesser extent by decreased fluvial sediment loads owing to extensive impoundment of rivers in the region. (author)

Characterizing Novel Archaeal Lineages in Salton Sea Sediments

Science.gov (United States)

Tarn, J.; Valentine, D. L.

2016-12-01

Biological communities in extreme environments are often dominated by microorganisms of the domain Archaea. Abundant microbial assemblages of this group are found in the hottest, saltiest, and most thermodynamically-limited ecosystems on earth. These taxing surroundings are thought to impose a state of chronic energy stress on resident organisms due to high costs of cellular maintenance relative to resource availability. Even in more temperate settings, Archaea are regularly associated with low-nutrient lifestyles, reflecting their adaptation to extreme, biologically-limiting conditions, which may be an ancestral, domain-wide trait. In this study, we seek to characterize the Archaeal community of the Salton Sea, where members of this domain are novel and highly abundant. Previous work by Swan et al. in 2010 showed that gradients in salinity, sulfate, carbon and nitrogen across sediment horizons of the Salton Sea are linked to changes in Archaeal dominance and community structure. In light of recent taxonomic revisions of the domain, I reclassified the 107 published small subunit rRNA Archaeal sequences from the 2010 study using updated reference databases. The majority of these Euryarchaeal sequences were reassigned to the so-called DPANN superphylum, with Pacearchaeota-related sequences being very abundant in shallow, organic-rich sediments. In deeper, energy-limited strata, several groups of Bathyarchaeota and one divergent DPANN clade were dominant. Ongoing metagenomic work on these sediment communities is being used to assemble genomes of these novel Archaeal groups. These results will help define genomic adaptations of Salton Sea Archaea to varying levels of energy stress as well as inform future cultivation efforts.

Organic carbon source and salinity shape sediment bacterial composition in two China marginal seas and their major tributaries.

Science.gov (United States)

Wang, Kai; Zou, Li; Lu, Xinxin; Mou, Xiaozhen

2018-08-15

Marginal sea sediments receive organic substrates of different origins, but whether and to what extent sediment microbial communities are reflective of the different sources of organic substrates remain unclear. To address these questions, sediment samples were collected in two connected China marginal seas, i.e., Bohai Sea and Yellow Sea, and their two major tributaries (Yellow River and Liao River). Sediment bacterial community composition (BCC) was examined using 16S rRNA gene pyrosequencing. In addition, physicochemical variables that describe environmental conditions and sediment features were measured. Our results revealed that BCCs changed with salinity and organic carbon (OC) content. Members of Gaiellaceae and Comamonadaceae showed a rapid decrease as salinity and phytoplankton-derived OC increased, while Piscirickettsiaceae and Desulfobulbaceae exhibited an opposite distribution pattern. Differences of riverine vs. marginal sea sediment BCCs could be mostly explained by salinity. However, within the marginal seas, sediment BCC variations were mainly explained by OC-related variables, including terrestrial-derived fatty acids (Terr_FA), phytoplankton-derived polyunsaturated fatty acids (Phyto_PUFA), stable carbon isotopes (δ 13 C), and carbon to nitrogen ratio (C/N). In addition to environmental variables, network analysis suggested that interactions among individual bacterial taxa might be important in shaping sediment BCCs in the studied areas. Copyright © 2018 Elsevier B.V. All rights reserved.

Mineral assemblages and their distribution patterns in the sediments of the Gulf of Bohai Sea

Energy Technology Data Exchange (ETDEWEB)

Chen, L; Luan, Z; Zheng, T; Xu, W; Dong, T

1980-01-01

This paper presents the results of a study on the mineral assemblages and their distribution patterns in the sediments of the Gulf of Bohai Sea. The 212 bottom-surface sediment samples were collected from the Gulf of Bohai Sea and its tributaries.

Exogenic geomorphic processes dynamics at the Black Sea coast, Russia

Science.gov (United States)

Kuznetsova, Yulia; Tsvetkova, Daria

2017-04-01

Nowadays there is an obvious grow of anthropogenic load going on in many areas worldwide. Under such conditions, intensive activation of a number of exogenic geomorphic processes may be observed. Moreover, if natural environment is aggressive itself their dynamics and rates may reach enormous values. Our work is conducted at the Black Sea coast, known for its mountainous topography, wet subtropical climate and intensive anthropogenic development (especially during the last decade due to the recent Olympic games). We chose two key basins near Sochi, Russia to study a number of presented exogenic processes, including rill, gully and channel erosion, weathering, suffusion and piping, soil creep. A set of field study methods is used to monitor the processes dynamics since 2005 (and late 1970s for soil creep). In addition, soil erosion rates and landslide susceptibility were modelled to get information of the watersheds dynamics. This is ongoing work, but the results of the passed period of observations will be resented. Special attention is paid to the processes connectivity and their input into sediment redistribution over the river basins.

Wind waves on the Black Sea: results of a hindcast study

Science.gov (United States)

Arkhipkin, V. S.; Gippius, F. N.; Koltermann, K. P.; Surkova, G. V.

2014-02-01

In this study we describe the wind waves fields on the Black Sea. The general aims of the work were the estimation of statistical wave parameters and the assessment of interannual and seasonal storm variability. The domain of this study was the entire Black Sea. Wave parameters were calculated by means of the SWAN wave model on a 5 km × 5 km rectangular grid. Initial conditions (wind speed and direction) for the period between 1948 and 2010 were derived from the NCEP/NCAR reanalysis. In our calculations the average significant wave height on the Black Sea does not exceed 0.7 m. Areas of most significant storminess are the south-western and the north-eastern corners as expressed in the spatial distribution of wave heights, wave lengths and periods. Besides that, long-term annual variations of storminess were estimated. Thus, linear trends of the annual total duration of storms and of their quantity are nearly stable over the reanalysis period. However, an intensification of storm activity is observed in the 1960s-1970s.

Marine environmental assessment in the Black Sea region- a case for the Turkish coastal zone

International Nuclear Information System (INIS)

Goektepe, G G.; Koeksal, G.; Osvath, I.

2001-01-01

'Marine Environmental Assessment of the Black Sea Region' Technical Cooperation Project, implemented by the International Atomic Energy Agency (IAEA) is presented. Environmental problems of the Black Sea eco-system and the current international efforts with regard to prevention of pollution are discussed. General aspects of the project are presented. A joint monitoring program initiated according to the work plan of the project among six Black Sea countries is outlined with emphasis on the monitoring program for the Turkish coastal zone. Concluding remarks are on the vital importance of sharing the scientific responsibility on the trans-boundary environmental problems

Real-Time PCR Quantification and Diversity Analysis of the Functional Genes aprA and dsrA of Sulfate-Reducing Prokaryotes in Marine Sediments of the Peru Continental Margin and the Black Sea.

Science.gov (United States)

Blazejak, Anna; Schippers, Axel

2011-01-01

Sulfate-reducing prokaryotes (SRP) are ubiquitous and quantitatively important members in many ecosystems, especially in marine sediments. However their abundance and diversity in subsurface marine sediments is poorly understood. In this study, the abundance and diversity of the functional genes for the enzymes adenosine 5'-phosphosulfate reductase (aprA) and dissimilatory sulfite reductase (dsrA) of SRP in marine sediments of the Peru continental margin and the Black Sea were analyzed, including samples from the deep biosphere (ODP site 1227). For aprA quantification a Q-PCR assay was designed and evaluated. Depth profiles of the aprA and dsrA copy numbers were almost equal for all sites. Gene copy numbers decreased concomitantly with depth from around 10(8)/g sediment close to the sediment surface to less than 10(5)/g sediment at 5 mbsf. The 16S rRNA gene copy numbers of total bacteria were much higher than those of the functional genes at all sediment depths and used to calculate the proportion of SRP to the total Bacteria. The aprA and dsrA copy numbers comprised in average 0.5-1% of the 16S rRNA gene copy numbers of total bacteria in the sediments up to a depth of ca. 40 mbsf. In the zone without detectable sulfate in the pore water from about 40-121 mbsf (Peru margin ODP site 1227), only dsrA (but not aprA) was detected with copy numbers of less than 10(4)/g sediment, comprising ca. 14% of the 16S rRNA gene copy numbers of total bacteria. In this zone, sulfate might be provided for SRP by anaerobic sulfide oxidation. Clone libraries of aprA showed that all isolated sequences originate from SRP showing a close relationship to aprA of characterized species or form a new cluster with only distant relation to aprA of isolated SRP. For dsrA a high diversity was detected, even up to 121 m sediment depth in the deep biosphere.

Flux, Budget and Sources of Black Carbon (BC) in the Continental Shelf of the Bohai and Yellow Seas, China

Science.gov (United States)

Fang, Y.; Chen, Y.; Tian, C.

2015-12-01

Black carbon (BC) derived from incomplete combustion of fossil fuels and biomass has received increasing attention due to their potential importance in a wide range of biogeochemical processes. China has been generally considered as the world's largest BC emitter. Due to a combination of the prevailing East Asia monsoon and large amounts of riverine outflow, BC released from China can be transported to the adjacent continental shelf seas, the Bohai Sea (BS) and Yellow Sea (YS). Based on measurements of BC in 191 surface sediments, 36 riverine water, and 2 seawater samples, as well as the reported BC data set of the aerosol samples in the Bohai Rim, the concentration, flux, and budget of BC in the BS and YS were investigated. The spatial distribution of the BC concentration in surface sediments was largely influenced by the regional hydrodynamic conditions, with high values mainly occurring in the central mud areas. The BC burial flux in the BS and YS ranged from 4 to 1100 μg/cm2/yr, and averaged 166 ± 200 μg/cm2/yr. The area-integrated sedimentary BC sink flux in the entire BS and YS was ~325 Gg/yr. The BC budget calculated in the BS showed that atmospheric deposition and riverine discharge played comparable importance in delivering BC to the BS, and sequestration to bottom sediments was the major BC output pattern, accounting for ~88% of the total input BC. Besides, we attempted to apportion the BC sources in the BS and YS surface sediments using PAHs (organic molecular proxies cogenerated with BC) and BC as an input data to the Positive Matrix Factorization (PMF) receptor model. Results showed that ~83% of the sediment BC was attributed to the combustion of fossil fuels, and the remaining ~17% was from biomass burning. Due to the differences in their production mechanisms and therefore physicochemical properties, the above distinction and quantification would help us better understand their different environmental behaviors in the complex continental shelf

Deciphering Equatorial Pacific Deep Sea Sediment Transport Regimes by Core-Log-Seismic Integration

Science.gov (United States)

Ortiz, E.; Tominaga, M.; Marcantonio, F.

2017-12-01

Investigating deep-sea sediment transportation and deposition regimes is a key to accurately understand implications from geological information recorded by pelagic sediments, e.g. climate signals. However, except for physical oceanographic particle trap experiments, geochemical analyses of in situsediments, and theoretical modeling of the relation between the bottom currents and sediment particle flux, it has remained a challenging task to document the movement of deep sea sediments, that takes place over time. We utilized high-resolution, multichannel reflection seismic data from the eastern equatorial Pacific region with drilling and logging results from two Integrated Ocean Drilling Program (IODP) sites, the Pacific Equatorial Age Transect (PEAT) 7 (Site U1337) and 8 (Site U1338), to characterize sediment transportation regimes on 18-24 Ma oceanic crust. Site U1337, constructed by a series of distinct abyssal hills and abyssal basins; Site U1338, located 570 km SE from Site U1337 site and constructed by a series of ridges, seamounts, and abyssal hills. These sites are of particular interest due to their proximity to the equatorial productivity zone, areas with high sedimentation rates and preservation of carbonate-bearing sediment that provide invaluable insights on equatorial Pacific ecosystems and carbon cycle. We integrate downhole geophysical logging data as well as geochemistry and physical properties measurements on recovered cores from IODP Sites U1337 and U1338 to comprehensively examine the mobility of deep-sea sediments and sediment diagenesis over times in a quasi-3D manner. We also examine 1100 km of high resolution underway seismic surveys from site survey lines in between PEAT 7 and 8 in order to investigate changes in sediment transportation between both sites. Integrating detailed seismic interpretations, high resolution core data, and 230Th flux measurements we aim to create a detailed chronological sedimentation and sediment diagenesis history

Inter-annual variability of exchange processes at the outer Black Sea shelf

Science.gov (United States)

Shapiro, Georgy; Wobus, Fred; Yuan, Dongliang; Wang, Zheng

2014-05-01

The advection of cold water below the surface mixed layer has a significant role in shaping the properties of the Cold Intermediate Layer (CIL) in the Black Sea, and thus the horizontal redistribution of nutrients. The minimal temperature of the CIL in the southwest deep region of the sea in summer was shown to be lower than the winter surface temperature at the same location, indicating the horizontal advective nature of CIL formation in the area (Kolesnikov, 1953). In addition to advection in the deep area of the sea, the transport of cold waters from the northwest Black Sea shelf across the shelf break in winter was shown to contribute to the formation of the CIL (Filippov, 1968; Staneva and Stanev, 1997). However less is known of the exchanges between the CIL waters and the outer shelf areas in summer, when a surface mixed layer and the underlying seasonal thermocline are formed. Ivanov et al. (1997) suggested that the cross frontal exchange within the CIL is strongly inhibited, so that CIL waters formed in the deep sea (i.e. offshore of the Rim Current) do not replenish the CIL waters onshore of the Rim Current (also known as near-bottom shelf waters, or BSW), due to strong cross frontal gradients in potential vorticity (PV). To the contrary, Shapiro et al. (2011) analysed in-situ observations over the period of 1950-2001 and showed a high correlation between the CIL temperatures in the open sea and outer shelf. However, the statistical methods alone were not able to clearly establish the relation between the cause and the consequences. In this study we use a 3D numerical model of the Black Sea (NEMO-SHELF-BLS) to quantify the exchange of CIL waters between the open sea and the outer northwest Black Sea shelf and to assess its significance for the replenishment of BSW on the outer shelf. The model has a resolution of 1/16º latitude × 1/12º longitude and 33 levels in the vertical. In order to represent near-bottom processes better, the model uses a hybrid

Total Sediment Thickness of the World's Oceans & Marginal Seas

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A digital total-sediment-thickness database for the world's oceans and marginal seas has been compiled by the NOAA National Geophysical Data Center (NGDC). The data...

Reconstructing the trophic history of the Black Sea shelf

Science.gov (United States)

Yunev, Oleg; Velikova, Violeta; Carstensen, Jacob

2017-11-01

In the last 50 years the Black Sea has undergone large changes driven by increasing anthropogenic pressures. We estimated the integrated annual primary production (APP) for different shelf regions during the early eutrophication phase (1963-1976) using chlorophyll a and winter nitrate concentrations as proxy observations of primary production to describe its seasonal variation. For comparison, APP was estimated during the period when eutrophication peaked (1985-1992). In the early eutrophication period APP was estimated at 64-89 g C m-2 yr-1 for most part of the shelf, except the shelf part influenced by the Danube River (the shallow waters off the Romanian and Bulgarian coasts) where APP was ∼126 g C m-2 yr-1. In these two different shelf parts, APP increased to 138-190 and 266-318 g C m-2 yr-1 during the peak eutrophication period. These spatial differences are attributed to the large nutrient inputs from the Danube River. The APP estimates provide new insight into the eutrophication history of the Black Sea shelf, documenting stronger signs of eutrophiction than observed in other enclosed seas such as the Baltic Sea. Since the peak eutrophication period APP is estimated to have decreased by approximately 15-20%.

Quality Assurance Project Plan for Verification of Sediment Ecotoxicity Assessment Ring(SEA Ring)

Science.gov (United States)

The objective of the verification is to test the efficacy and ability of the Sediment Ecotoxicity Assessment Ring (SEA Ring) to evaluate the toxicity of contaminants in the sediment, at the sediment-water interface, and WC to organisms that live in those respective environments.

Radionuclide uptake in red macroalgae from the Bulgarian Black Sea coast

International Nuclear Information System (INIS)

Nonova, Tz.; Strezov, A.

2005-01-01

Technogenic and natural radionuclide content in red macroalgae (Ceramium rubrum, Corallina officinalis and Callithamnion corymbosum) from the Bulgarian Black Sea coast, collected in the period 1992-2003, was studied by low-level gamma-spectrometry. The data show that the nuclide concentrations depend on macroalgae species and coast locations. The highest nuclide content was measured in Ceramium rubrum species. The 137 Cs mean value is 9.8 Bq/kg, 19.6 Bq/kg for 226 Ra and 17 Bq/kg for 210 Pb. The radionuclide pollution is considerably small due to the absence of nuclear facilities along the Bulgarian Black Sea coast. (author)

Black sea annual and inter-annual water mass variations from space

DEFF Research Database (Denmark)

Yildiz, H.; Andersen, Ole Baltazar; Simav, M.

2011-01-01

influenced by the leakage of hydrological signals from the surrounding land. After applying the corresponding correction, we found a good agreement with water mass variations derived from steric-corrected satellite altimetry observations. Both GRACE and altimetry show significant annual water mass variations......This study evaluates the performance of two widely used GRACE solutions (CNES/GRGS RL02 and CSR RL04) in deriving annual and inter-annual water mass variations in the Black Sea for the period 2003–2007. It is demonstrated that the GRACE derived water mass variations in the Black Sea are heavily...

Measurements of Sediment Transport in the Western Adriatic Sea

Science.gov (United States)

Sherwood, C. R.; Hill, P. S.

2003-12-01

Instrumented bottom tripods were deployed at two depths (10 and 20 m) off the mouth of the Chienti River in the western Adriatic Sea from November 2002 to May 2003 as part of the EuroSTRATAFORM Po and Apennine Sediment Transport and Accumulation (PASTA) Experiment. Waves, currents, and proxies for suspended-sediment concentrations were measured with upward-looking acoustic Doppler current meters, downward looking pulse-coherent acoustic Doppler profilers, single-point acoustic Doppler velocimeters, and acoustic and optical backscatter sensors. Flow was dominated by the western Adriatic coastal current (WACC) during the experiment. Mean southward alongshore velocity 2 m below the surface was 0.10 m/s at the 10-m site and 0.23 m/s at the 20-m site, and flow was modulated by tides, winds, and fluctuating riverflow. The largest waves (3 m significant height) were generated by winds from the southeast during a Sirocco event in late November that generated one of the few episodes of sustained northward flow and sediment transport. Most of the time, however, sediment resuspension and transport was dominated by Bora events, when downwelling-favorable winds from the northeast generated waves that resuspended sediment and simultaneously enhanced southward flow in the WACC. Mean flow near the bottom was slightly offshore at the 20-m site (0.01 m/s at 3 m above the bottom), but there was no significant correlation between downwelling and wave-induced resuspension, and cross-shelf sediment fluxes were small. The combination of persistent southward flow with low rates of cross-shelf leakage makes the WACC an efficient conduit for sediment past the Chienti region. If these observations are representative of typical winter conditions along the entire western Adriatic, they may help explain the enigmatic development of Holocene shelf-edge clinoforms that have formed hundreds of kilometers south of the Po River, which provides most of the sediment to the Adriatic Sea. Future data

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.

Concentrations of some elements in the coastal sea sediments. Bays with marinas

International Nuclear Information System (INIS)

Obhodas, J.; Kutle, A.; Valkovic, V.

2006-01-01

Surface sediments and sediment cores from two bays in the Adriatic sea (Punat Bay and Soline Bay, Croatia) have been analyzed for a number of elements, in particular: Ti, V, Mn, Fe, Cu, Zn, As and Pb, by using XRF. Maps of elemental distribution in surface sediments show increased concentrations for some elements present in antifouling paints (Cu, Zn, Pb) near the service areas in the villages or marinas. Core profiles for these elements were used to evaluate the environmental impact of newly constructed marinas. Source partition indicates the influence of other sources located in near by villages. The critical factor in these considerations was shown to be water exchange with the open sea. (author)

Modeling of Nonlinear Hydrodynamics of the Coastal Areas of the Black Sea by the Chain of the Proprietary and Open Source Models

Science.gov (United States)

Kantardgi, Igor; Zheleznyak, Mark; Demchenko, Raisa; Dykyi, Pavlo; Kivva, Sergei; Kolomiets, Pavlo; Sorokin, Maxim

2014-05-01

The nearshore hydrodynamic fields are produced by the nonlinear interactions of the shoaling waves of different time scales and currents. To simulate the wind wave and swells propagated to the coasts, wave generated near shore currents, nonlinear-dispersive wave transformation and wave diffraction in interaction with coastal and port structure, sediment transport and coastal erosion the chains of the models should be used. The objective of this presentation is to provide an overview of the results of the application of the model chains for the assessment of the wave impacts on new construction designed at the Black Sea coasts and the impacts of these constructions on the coastal erosion/ accretion processes to demonstrate needs for further development of the nonlinear models for the coastal engineering applications. The open source models Wave Watch III and SWAN has been used to simulate wave statistics of the dedicated areas of the Black Sea in high resolution to calculated the statistical parameters of the extreme wave approaching coastal zone construction in accordance with coastal engineering standards. As the main tool for the costal hydrodynamic simulations the modeling system COASTOX-MORPHO has been used, that includes the following models. HWAVE -code based on hyperbolic version of mild slope equations., HWAVE-S - spectral version of HWAVE., BOUSS-FNL - fully nonlinear system of Boussinesq equations for simulation wave nonlinear -dispersive wave transformation in coastal areas. COASTOX-CUR - the code provided the numerical solution of the Nonlinear Shallow Water Equations (NLSWE) by finite-volume methods on the unstructured grid describing the long wave transformation in the coastal zone with the efficient drying -wetting algorithms to simulate the inundation of the coastal areas including tsunami wave runup. Coastox -Cur equations with the radiation stress term calculated via near shore wave fields simulate the wave generated nearhore currents. COASTOX

Phosphorus recycling and burial in Baltic Sea sediments with contrasting redox conditions

DEFF Research Database (Denmark)

Mort, Haydon P; Slomp, Caroline P; Gustafson, Bo G

2010-01-01

. Most burial of P takes place as organic P. We find no evidence for significant authigenic Ca–P formation or biogenic Ca–P burial. The lack of major inorganic P burial sinks makes the Baltic Sea very sensitive to the feedback loop between increased hypoxia, enhanced regeneration of P and increased......In this study, redox-dependent phosphorus (P) recycling and burial at 6 sites in the Baltic Sea is investigated using a combination of porewater and sediment analyses and sediment age dating (210Pb and 137Cs). We focus on sites in the Kattegat, Danish Straits and Baltic Proper where present...... be accounted for in budgets and models for the Baltic Sea....

A model technical cooperation project on the marine radioactivity assessment in the Black Sea Region

International Nuclear Information System (INIS)

Goektepe, B. G.; Koeksal, G.; Osvath, I.; Koese, A.; Kuecuekcezzar, R.; Varinlioglu, A.; Guengoer, E.

2002-01-01

Marine Environmental Assessment of the Black Sea Region is a wide scope Regional Technical Co-operation Project coded as RER/2/003 implemented by the International Atomic Energy Agency (IAEA) in the period 1995-2001.This multidisciplinay project was designed in response to the needs of participating Member States - the six Black Sea coastal countries (Bulgaria, Romania, Ukraine, Russian Federation, Georgia and Turkey)- to establish capabilities for reliably assessing radionuclides in the Black Sea environment and applying tracer techniques to marine pollution studies. The IAEA assisted laboratories in the region by providing expert services, training, equipment and materials (Goektepe et al., 1998; Osvath et al., 1997-2000)

Transfer of organic carbon through marine water columns to sediments – insights from stable and radiocarbon isotopes of lipid biomarkers

OpenAIRE

S. G. Wakeham; A. P. McNichol

2014-01-01

Compound-specific 13C and 14C compositions of diverse lipid biomarkers (fatty acids, alkenones, hydrocarbons, sterols and fatty alcohols) were measured in sinking particulate matter collected in sediment traps and from underlying surface sediments in the Black Sea, the Arabian Sea and the Ross Sea. The goal was to develop a multiparameter approach to constrain relative inputs of organic carbon (OC) from marine biomass, terrigenous vascular-plant and relict-kerogen sources. U...

Dynamics of macrozoobenthos in the Southern Bulgarian Black Sea coastal and open-sea areas

Directory of Open Access Journals (Sweden)

S. STOYKOV

2001-06-01

Full Text Available The paper presents results of analysis of 96 macrozoobenthic samples, collected on a seasonal basis in Bourgas Bay and in open-sea areas offshore Cape Emine (Bulgarian Black Sea in 1996 and 1998. In total 96 taxa were established, distributed in four groups: Polychaeta, Mollusca, Crustacea and “Diversa”. The average density of populations was 1756 ind.m-2 with a predominating abundance of Polychaeta species. The average biomass estimated was 183.02 g.m-2, formed mainly by representatives of Mollusca. The latter species were measured together with the shells, which appraised their individual weights. Seven of the species found had a coefficient of constancy more than 50%. These were the most adapted species to the environmental conditions of the investigated areas. The quantitative and qualitative assessments in this study demonstrate an increasing tendency in the parameters obtained (density, biomass, species diversity in comparison with previous investigations in the early 1990-s, when intensive anthropogenic influence was widely perceived to misbalance the Black Sea ecosystem. The method of Warwick (1986 applied to characterize the water quality of the studied areas allowed us to define them as rather clean or moderately polluted aquatories.

Oxygen-18, deuterium and tritium in the Black Sea and the Sea of Marmara

International Nuclear Information System (INIS)

Rank, D.; Oezsoy, E.; Salihoglu, I.

1999-01-01

The stable isotopes 18 O and 2 H, together with the transient tracer 3 H can be used to identify origins and characteristics of distinct water masses in the Black Sea, and in its smaller neighbour, the Marmara Sea, connected between them and to the Mediterranean Sea through the Straits of Bosphorus and Dardanelles, respectively. Exchange through the system and the water mass formation and evolution are characterised, based on the isotope measurements. Spatial coverage including the shelf and deep regions, with improved accuracy and reduced noise provide-definitive assessments of pycnocline and deep mixing in the system. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

First evaluation of neustonic microplastics in Black Sea waters.

Science.gov (United States)

Aytan, Ulgen; Valente, Andre; Senturk, Yasemen; Usta, Riza; Esensoy Sahin, Fatma Basak; Mazlum, Rahsan Evren; Agirbas, Ertugrul

2016-08-01

The Black Sea has a high risk of plastic pollution given the high river discharge of several industrialized countries into this semi-enclosed sea. Here, for the first time, the occurrence and distribution of microplastics are reported for the Black Sea. Microplastics were assessed from zooplankton samples taken during two cruises along the south eastern coast of the Black Sea in the November of 2014 and February of 2015. In each cruise neuston samples were collected at 12 stations using a WP2 net with 200 μm mesh. Microplastics (0.2-5 mm) were found in 92% of the samples. The primary shapes were fibres (49.4%) followed by plastic films (30.6%) and fragments (20%), and no micro beads were found. Average microplastic concentration in November (1.2 ± 1.1 × 10(3) par. m(-3)) was higher than in February (0.6 ± 0.55 × 10(3) par. m(-3)). Reduced concentrations in February were possibly caused by increased mixing. The highest concentrations of microplastics were observed in offshore stations during November sampling. The heterogeneous spatial distribution (0.2 × 10(3)-3.3 × 10(3) par. m(-3) for all samples) and accumulation in some stations could be associated to transport and retention mechanisms linked with wind and the dynamics of the rim current, as well by different sources of plastic. There were no statistically significant differences in MP concentration between sampling stations and sampling periods (t-test, p pollution and there is an urgency to understand their origins, transportation and effects on marine life. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optical properties of sea ice doped with black carbon - an experimental and radiative-transfer modelling comparison

Science.gov (United States)

Marks, Amelia A.; Lamare, Maxim L.; King, Martin D.

2017-12-01

Radiative-transfer calculations of the light reflectivity and extinction coefficient in laboratory-generated sea ice doped with and without black carbon demonstrate that the radiative-transfer model TUV-snow can be used to predict the light reflectance and extinction coefficient as a function of wavelength. The sea ice is representative of first-year sea ice containing typical amounts of black carbon and other light-absorbing impurities. The experiments give confidence in the application of the model to predict albedo of other sea ice fabrics. Sea ices, ˜ 30 cm thick, were generated in the Royal Holloway Sea Ice Simulator ( ˜ 2000 L tanks) with scattering cross sections measured between 0.012 and 0.032 m2 kg-1 for four ices. Sea ices were generated with and without ˜ 5 cm upper layers containing particulate black carbon. Nadir reflectances between 0.60 and 0.78 were measured along with extinction coefficients of 0.1 to 0.03 cm-1 (e-folding depths of 10-30 cm) at a wavelength of 500 nm. Values were measured between light wavelengths of 350 and 650 nm. The sea ices generated in the Royal Holloway Sea Ice Simulator were found to be representative of natural sea ices. Particulate black carbon at mass ratios of ˜ 75, ˜ 150 and ˜ 300 ng g-1 in a 5 cm ice layer lowers the albedo to 97, 90 and 79 % of the reflectivity of an undoped clean sea ice (at a wavelength of 500 nm).

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

A synthesis of Cenozoic sedimentation in the North Sea

DEFF Research Database (Denmark)

Anell, Ingrid Anna Margareta; Thybo, Hans; Rasmussen, E.S.

2012-01-01

study provides a regional synthesis of sedimentation based on a comprehensive interpretation of a regionally covering reflection seismic data set. We relate observations of sediment characteristics and unconformities to the geological evolution. The timing, regional expression and stratigraphic...... characteristics of many unconformities indicate that they were generated by eustatic sea-level fall, often in conjunction with other processes. Early Cenozoic unconformities, however, relate to tectonism associated with the opening of the North Atlantic. From observation on a regional scale, we infer...

Remobilisation of artificial radionuclides from the sediment of the Irish Sea

International Nuclear Information System (INIS)

Hunt, G.J.; Kershaw, P.J.

1990-01-01

The past decade has seen significant decreases in discharges of radioactivity in liquid wastes from the British Nuclear Fuels plc (BNFL) plant at Sellafield. Concentrations of many Sellafield-derived radionuclides in the water of the Irish Sea have decreased as a result. This will result in the return of previously contaminated sediment to the sediment surface and enhanced seawater/pore-water mixing by bio-irrigation, and may be responsible for higher rates of particle exchange across the sediment-seawater interface. In these circumstances, the decrease in seawater concentrations might be expected to be accompanied by the remobilisation of sediment-bound radionuclides into the water column. We have tested this hypothesis in the Sellafield situation in two ways. First, the differences were examined between measured concentrations of radionuclides in sea water and the concentrations which are to be expected on the basis of extrapolation from the conditions of steadier discharge rates experienced in the past. Secondly, modelling studies have shown that migration of radionuclides into the water phase is likely under these conditions. (author)

Polychlorinated biphenyls and pesticides in surficial coastal sediments of the Ligurian Sea

Energy Technology Data Exchange (ETDEWEB)

Bertolotto, R.M.; Cuneo, C.; Albanese, S. [ARPAL, Direzione Scientifica, Genova (Italy); Magherini, A. [ARPAL, Dipartimento di Genova, Genova (Italy); Frignani, M.; Bellucci, L.G.; Alvarado-Aguilar, D. [ISMAR, Sezione di Geologia Marina, Bologna (Italy)

2004-09-15

Polychlorinated biphenyls (PCBs) and chlorinated pesticides, such as DDT and its analogues, are organic contaminants widespread throughout the terrestrial and oceanic environments due to their common use and their resistance to degradation. Since harmful effects have been associated to these chemicals and well documented, they are classified as priority pollutants by both the US Environmental Protection Agency (EPA) and the European Union. Because of the very low solubility in water and the tendency to adsorb onto sediment particles, the ultimate fate of both PCBs and DDTs in the marine environment is the incorporation into sediments. Hence, the concentrations of these chlorinate chemicals in bottom sediments can provide an insight on the quality of the environment and the potential threat to marine organisms and human beings. The Ligurian Sea belongs to the north part of the western Mediterranean. The coastal morphology of the Liguria Region is rather variable, and frequently cliffs drop sheer to the sea. The limited width of the coastal zone, comprised between the sea and the mountains, determined a gathering of the urban areas with a consequent concentration of both civil and industrial presence in a narrow but highly populated territory. In particular Genova, but also other cities have a long history of industrial and harbour activities, whereas long tracts of the coast are dedicated to tourism. The circulation of the Ligurian Sea is rather well known. In particular, surface and intermediate currents follow a cyclonic circulation. However local circulation is the true responsible of the dispersion of sediment material along the coast, and these alongshore currents often cause an eastward oriented transport. The Ligurian coastal zone is very developed, and hosts all sort of industrial, agricultural and tourist activities that can be sources of persistent organochlorine chemicals. Therefore, the purpose of this study was to assess concentrations, distributions

Chemical and biological evaluation of sediments from the Wadden Sea, The Netherlands

NARCIS (Netherlands)

Brink, van den P.J.; Kater, B.J.

2006-01-01

We describe the results of an evaluation of marine sediments using chemical measurements and bioassays. Four groups of chemicals, i.e., heavy metals, PAHs, chlorinated aromatic compounds, and tin compounds, were measured at 16 locations in the Wadden Sea, The Netherlands. Extractions of sediments

Dissolved rare earth elements in the Black Sea

NARCIS (Netherlands)

Schijf, Johan; Baar, Hein J.W. de; Wijbrans, Jan R.; Landing, William M.

1991-01-01

Concentrations of rare earths in the deep anoxic Black Sea are about one order of magnitude higher than in normal open ocean waters. From a minimum at the suboxic-anoxic interface at about 107 m depth, concentrations increase strongly to a maximum at about 300–400 m depth. Concentrations of Ce range

Sediment transfer from beach to shoreface: The sediment budget of an accreting beach on the Danish North Sea coast

DEFF Research Database (Denmark)

Aagaard, Troels

2011-01-01

The sediment budget along the southern part of the exposed Danish North Sea coast was assessed through a combination of cross-shore profile analysis, numerical modeling and field measurements of cross-shore and longshore sediment transport at the boundary between the upper and the lower shorefaces...

Wave modelling south of the Danube Delta in the Black Sea

Science.gov (United States)

Rusu, Eugen; Butunoiu, Dorin

2015-04-01

processes. The first is dominant and it can be considered as a constructive process. This corresponds to the most common wave propagation pattern in the target area (waves coming from the northeast). In this case, the alluvial river input combines with the longshore sediment transport. This process determined the generation of the Sacalin Island and controls now its southern extension. The second is in fact a destructive process. This corresponds to the situations of very strong storms with waves coming from the southeast (and also in some cases from the east). Such cases of strong storm waves coming from the southeast are not very common in the target area. Nevertheless, such conditions may be encountered and moreover, they really occurred in the winter of 2013 leading to a strong penetration of the waves through the Sacalin Island that changed the coastal configuration and affected the local habitat. Various scenarios have been analyzed and the model results help in a better understanding of the coastal dynamics in this area. Keywords: Black Sea, waves, SWAN, Sacalin island, coastal dynamics. ACKNOWLEDGEMENT: This work was supported by a grant of the Romanian Ministry of National Education, CNCS - UEFISCDI, project number PN-II-ID-PCE-2012-4-0089 (project DAMWAVE).

Environment-Dependent Distribution of the Sediment nifH-Harboring Microbiota in the Northern South China Sea

Science.gov (United States)

Yang, Jinying; Li, Jing; Luan, Xiwu; Zhang, Yunbo; Gu, Guizhou; Xue, Rongrong; Zong, Mingyue; Klotz, Martin G.

2013-01-01

The South China Sea (SCS), the largest marginal sea in the Western Pacific Ocean, is a huge oligotrophic water body with very limited influx of nitrogenous nutrients. This suggests that sediment microbial N2 fixation plays an important role in the production of bioavailable nitrogen. To test the molecular underpinning of this hypothesis, the diversity, abundance, biogeographical distribution, and community structure of the sediment diazotrophic microbiota were investigated at 12 sampling sites, including estuarine, coastal, offshore, deep-sea, and methane hydrate reservoirs or their prospective areas by targeting nifH and some other functional biomarker genes. Diverse and novel nifH sequences were obtained, significantly extending the evolutionary complexity of extant nifH genes. Statistical analyses indicate that sediment in situ temperature is the most significant environmental factor influencing the abundance, community structure, and spatial distribution of the sediment nifH-harboring microbial assemblages in the northern SCS (nSCS). The significantly positive correlation of the sediment pore water NH4+ concentration with the nifH gene abundance suggests that the nSCS sediment nifH-harboring microbiota is active in N2 fixation and NH4+ production. Several other environmental factors, including sediment pore water PO43− concentration, sediment organic carbon, nitrogen and phosphorus levels, etc., are also important in influencing the community structure, spatial distribution, or abundance of the nifH-harboring microbial assemblages. We also confirmed that the nifH genes encoded by archaeal diazotrophs in the ANME-2c subgroup occur exclusively in the deep-sea methane seep areas, providing for the possibility to develop ANME-2c nifH genes as a diagnostic tool for deep-sea methane hydrate reservoir discovery. PMID:23064334

210Pb dating of Baltic Sea sediments

International Nuclear Information System (INIS)

Gellermann, R.

1990-01-01

The paper reports on the results of 210 Pb measurement in sediment cores from the Baltic Sea. The models used for the interpretation are derived and discussed. In general, the sedimentation parameters calculated with different models are consistent. However, parameters of cores independently taken on same partly show clearly differing values. The reasons of this observation have to be analysed by further studies. An essential problem considered in this paper is the dating of disturbed sediments. The use of such cores for the reconstruction of the input history of chemical indicators requires a deconvolution of data. The response function necessary for this procedure can be derived from 210 Pb measurements. The results of such a reconstruction considerably differ from those obtained by conventional dating models. The analysis of the measuring uncertainty of the indicator (e.g. lead) in the deconvolution procedure unveals the limits of the method and prevents it from overinterpretation. (orig.) [de

RATIONALE OF KUYALNIK ESTUARY FILLING ENVIRONMENTAL SAFETY BY THE BLACK SEA WATERS. CHEMICAL ASPECTS

Directory of Open Access Journals (Sweden)

V. P. Antonovich

2014-11-01

Full Text Available It was found that currently sulphate and calcium ions content in Kuyalnik brine close to the solubility product of CaSO4. If brine will not by dilute precipitation of gypsum may be expect in prospectstive. It is shown that the dilution of the Kuyalnik brine by seawater willreduces the concentration of calcium and sulfate ions reducing their solubility product and making it impossible the formation of calcium sulfate and precipitation of gypsum. On the basis of established the contents of some heavy metals, polyarenes, chlorinated pesticides and polychlorinated biphenyls which were in water and sediments of the Gulf of Odessa , brine and peloids Kuyalnik estuary pronounced more pollution by priority toxicants of estuary compared with seawater. Concluded tht environmental safety of Kuyalnik estuary filling by the Black Sea waters.

Comparison of sup(115m)Cd accumulation from sediments and sea water by polychaete worms

International Nuclear Information System (INIS)

Ueda, Taishi; Nakamura, Ryoichi; Suzuki, Yuzuru

1976-01-01

To know the role played by marine sediments in influencing the fate of discharged metals, (1) the interaction of metals between sediments and deposit-feeder marine worms (Nereis japonica), and (2) uptake and excretion of metals by worms were examined by laboratory experiments using sup(115m)Cd. Worms directly in contact with sup(115m)Cd-sediments accumulated sup(115m)Cd six times more than worms that were not in contact with the sup(115m)Cd sediments during the 8 days of experimentation and 12% of sup(115m)Cd in sediments were noted to be transfered to worms per unit. Comparing the concentration factor of 22 (from sea water) with accumulation from sediments, it was assumed that sup(115m)Cd in sediments would give the effect of 1/200 to the accumulation of sup(115m)Cd by worms in sea water to the accumulation of sup(115m)Cd. Further, to simulate these results close to that occuring in the natural ecosystem, the distribution of sup(115m)Cd in sea water, sediments and alga were also examined by means of a curve analysis of the distribution pattern by a three compartment model. It proved that the activity ratios of sup(115m)Cd were 9 for sediments and 21 for alga, which was similar to 22 for worms. (auth.)

Atmospheric circulation and storm events in the Black Sea and Caspian Sea

Science.gov (United States)

Surkova, Galina V.; Arkhipkin, Victor S.; Kislov, Alexander V.

2013-12-01

Extreme sea storms are dangerous and a potential source of damage. In this study, we examine storm events in the Black Sea and Caspian Sea, the atmosphere circulation patterns associated with the sea storm events, and their changes in the present (1961-2000) and future (2046-2065) climates. A calendar of storms for the present climate is derived from results of wave model SWAN (Simulating WAves Nearshore) experiments. On the basis of this calendar, a catalog of atmospheric sea level pressure (SLP) fields was prepared from the NCEP/NCAR reanalysis dataset for 1961-2000. The SLP fields were subjected to a pattern recognition algorithm which employed empirical orthogonal decomposition followed by cluster analysis. The NCEP/NCAR reanalysis data is used to evaluate the occurring circulation types (CTs) within the ECHAM5-MPI/OM Atmosphere and Ocean Global Circulation Model (AOGCM) for the period 1961-2000. Our analysis shows that the ECHAM5-MPI/OM model is capable of reproducing circulation patterns for the storm events. The occurrence of present and future ECHAM5-MPI/OM CTs is investigated. It is shown that storm CTs are expected to occur noticeably less frequently in the middle of the 21st century.

Nutritional evaluation of aquaculture mussels (M. galloprovincialis from the Black Sea, Bulgaria

Directory of Open Access Journals (Sweden)

Merdzhanova Albena

2016-06-01

Full Text Available In recent years black mussels are one of the most commercially important species from the Bulgarian Black Sea. The marine mollusks are valuable healthy food, low in calories and fats and high in proteins. They are a major dietary source of fat soluble pigments - astaxanthin, carotenoids and polyunsaturated fatty acids (PUFA. To our knowledge the information about the nutritional quality of mussels from the Bulgarian Black Sea waters, based on chemical composition, fat soluble pigments, cholesterol and PUFA content is very limited. The aim of the present study is to determine and compare protein, lipid, carbohydrate and energy values, fat soluble pigments, cholesterol and fatty acid composition in farmed mussels (Mytilus galloprovincialis from the Bulgarian northern and southern parts of the Black Sea coast. The mussel samples were analyzed for lipids (Bligh & Dyer method, crude proteins (Kjeldahl method, carbohydrates and moistures according to the AOAC (1990 methods. Fatty acids were analyzed by the GC-MS system. Fat soluble pigments and cholesterol were analyzed simultaneously by the RP-HPLC system. Lipid and protein content were found to be higher in mussels from the northern region. In accordance with the Commission Regulation (EC No. 116/2010 all analyzed mussel samples can be classified as high in protein and low in fats and carbohydrates. The amount of cholesterol, contained in all mussel populations is significantly low, while the omega-3 (n-3 is significantly higher than the omega-6 PUFA. A portion of 100 g edible tissue provides 0.500 g more of the required amount of eicosapentaenoic acid (20:5 and docosahexaenoic acid (22:6 n-3 PUFA according to EFSA (2012. It can be concluded that the studied mussel aquaculture in the Black Sea is beneficial food for the human health and it is advisable to be part of a proper or a preventive diet of Bulgarian consumers.

Temperature, salinity, and nutrients data collected from North Atlantic Ocean, White Sea, Mediterranean Sea, Black Sea, and Sea of Azov from 1924-03-19 to 1989-11-19 by multiple Soviet Union institutes (NODC Accession 0077413)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, and nutrients data collected from North Atlantic Ocean, White Sea, Mediterranean Sea, Black Sea, and Sea of Azov from 1924-03-19 to 1989-11-19...

75 FR 17618 - Fisheries of the Northeastern United States; Black Sea Bass Recreational Fishery; Emergency Rule...

Science.gov (United States)

2010-04-07

... Analyst, (978) 281-9104. SUPPLEMENTARY INFORMATION: Correction Rule NMFS published an emergency rule to... reconsider their previous recommendations regarding the Acceptable Biological Catch (ABC) for black sea bass for the 2010 fishing year. The SSC concluded that the ABC for black sea bass could be increased from 2...

Radiocesium distribution on sea sediment and in benthic organisms in the north-east Japan coast

Energy Technology Data Exchange (ETDEWEB)

Ono, Tsuneo; Ambe, Daisuke; Kaeriyama, Hideki; Shigenobu, Yuya; Fujimoto, Ken; Saito, Hajime; Miki, Shiduho; Setou, Takashi; Morita, Takami; Watanabe, Tomowo [National Research Institute of Fisheries Sciences, Fisheries Research Agency, 2-12-4, Fukuura, Kanazawaward, Yokohama, Kanagawa, 236-8648 (Japan); Sawada, Hideki [National Resarch Institute of Fisheries Engineering, Fisheries Research Agency, 7620-7, Hasaki, Kamisu-shi, Ibaraki, 314-0408 (Japan)

2014-07-01

A large amount of radioactive materials, especially radiocesium, were discharged into the western North Pacific Ocean by the Fukushima Daiichi Nuclear Power Plant (FDNPP) disaster following the Great East Japan Earthquake and tsunami on 11 March 2011. Although radiocesium concentrations in sea water had quickly diminished via water mixing processes, significant amount still existed on sea floors near Fukushima Prefecture. To assess present distributions and/or spatio-temporal variations of sea sediment radiocesium and its potential affection to benthic ecosystems, we had conducted 5'x5' 2-D observation of sea sediment radiocesium concentrations repeatedly from Feb. 2012 to Jul. 2013. Off Fukushima Prefecture, the higher concentration area of radioactive cesium was often observed in the south area from the FDNPP and a north-south high value band was tended to be along the isobaths around 100 m where the concentration values up to thousands Bq/kg-dry order were observed. The concentrations generally decreased eastward from the high concentration band. At many surveyed positions, the vertical profiles of the radiocesium concentrations in sea sediment showed an exponentially decreasing in deeper layer. The influence of the FDNPP was suggested to generally reach up to 10 cm depth from sediment-surface. A negative correlation was found between the radiocesium concentration and median grain size of the sediment, suggesting that the adsorption capability of sediment for cesium associated with grain size possibly has a large contribution to the formation process of the spatial distribution pattern of the radiocesium concentration. In contrast to the land sediment, Chemical reaching experiment results showed that the radiocesium concentration in the organic component of bottom sediment has higher value than that of bulk sediment, suggesting that non-exchangeable adsorption cite of mineral component of marine sediments had already occupied by stable cesium (~2 nM in

Micro contaminants in surface sediments and macrobenthic invertebrates of the North Sea

NARCIS (Netherlands)

Everaarts, J.M.; Fischer, C.V.

1989-01-01

Trace metal concentrations (copper, zinc, cadmium and lead) were measured in the silt fraction (grainsize < 63 µm) of surface sediment of the North Sea. The concentrations varied in different areas of the Dutch continental shelf of the North Sea. The trace metal concentrations were highly related

Towards integrated assessment of the northern Adriatic Sea sediment budget using remote sensing

Science.gov (United States)

Taramelli, A.; Filipponi, F.; Valentini, E.; Zucca, F.; Gutierrez, O. Q.; Liberti, L.; Cordella, M.

2014-12-01

Understanding the factors influencing sediment fluxes is a key issue to interpret the evolution of coastal sedimentation under natural and human impact and relevant for the natural resources management. Despite river plumes represent one of the major gain in sedimentary budget of littoral cells, knowledge of factors influencing complex behavior of coastal plumes, like river discharge characteristics, wind stress and hydro-climatic variables, has not been yet fully investigated. Use of Earth Observation data allows the identification of spatial and temporal variations of suspended sediments related to river runoff, seafloor erosion, sediment transport and deposition processes. Objective of the study is to investigate sediment fluxes in northern Adriatic Sea by linking suspended sediment patterns of coastal plumes to hydrologic and climatic forcing regulating the sedimentary cell budget and geomorphological evolution in coastal systems and continental shelf waters. Analysis of Total Suspended Matter (TSM) product, derived from 2002-2012 MERIS time series, was done to map changes in spatial and temporal dimension of suspended sediments, focusing on turbid plume waters and intense wind stress conditions. From the generated multi temporal TSM maps, dispersal patterns of major freshwater runoff plumes in northern Adriatic Sea were evaluated through spatial variability of coastal plumes shape and extent. Additionally, sediment supply from river distributary mouths was estimated from TSM and correlated with river discharge rates, wind field and wave field through time. Spatial based methodology has been developed to identify events of wave-generated resuspension of sediments, which cause variation in water column turbidity, occurring during intense wind stress and extreme metocean conditions, especially in the winter period. The identified resuspension events were qualitatively described and compared with to hydro-climatic variables. The identification of spatial and

Modeling Anthropogenic Impact on Sediment Balance and Relative Sea-Level Rise in Contemporary and Future Deltas

Science.gov (United States)

Tessler, Z. D.; Vorosmarty, C. J.; Overeem, I.; Syvitski, J. P.

2017-12-01

Modern deltas are dependent on human-mediated freshwater and sediment fluxes. Changes to these fluxes impact delta biogeophysical functioning, and affect the long-term sustainability of these landscapes for both human and natural systems. Here we present contemporary estimates of long-term mean sediment balance and relative sea-level rise across 46 global deltas. We model ongoing development and scenarios of future water resource management and hydropower infrastructure in upstream river basins to explore how changing sediment fluxes impact relative sea-level in coastal delta systems. Model results show that contemporary sediment fluxes, anthropogenic drivers of land subsidence, and sea-level rise result in relative sea-level rise rates in deltas that average 6.8 mm/year. Currently planned or under-construction dams can be expected to increase rates of relative sea-level rise on the order of 1 mm/year. Some deltas systems, including the Magdalena, Orinoco, and Indus, are highly sensitive to future impoundment of river basins, with RSLR rates increasing up to 4 mm/year in a high-hydropower-utilization scenario. Sediment fluxes may be reduced by up to 60% in the Danube and 21% in the Ganges-Brahmaputra-Megnha if all currently planned dams are constructed. Reduced sediment retention on deltas due to increased river channelization and local flood controls increases RSLR on average by nearly 2 mm/year. Long-term delta sustainability requires a more complete understanding of how geophysical and anthropogenic change impact delta geomorphology. Strategies for sustainable delta management that focus on local and regional drivers of change, especially groundwater and hydrocarbon extraction and upstream dam construction, can be highly impactful even in the context of global climate-induced sea-level rise.

Vertical distribution of (241)Pu in the southern Baltic Sea sediments.

Science.gov (United States)

Strumińska-Parulska, Dagmara I

2014-12-15

The vertical distribution of plutonium (241)Pu in marine sediments can assist in determining the deposition history and sedimentation process of analyzed regions. In addition, (241)Pu/(239+240)Pu activity ratio could be used as a sensitive fingerprint for radioactive source identification. The present preliminary studies on vertical distribution of (241)Pu in sediments from four regions of the southern Baltic Sea are presented. The distribution of (241)Pu was not uniform and depended on sediment geomorphology and depth as well as location. The highest concentrations of plutonium were found in the surface layers of all analyzed sediments and originated from the Chernobyl accident. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characteristics of humic and fulvic acids in Arabian Sea sediments

Digital Repository Service at National Institute of Oceanography (India)

Sardessai, S.

Humic and fulvic acids isolated from some of the shelf, slope and offshore sediments of the Arabian Sea were studied. The molecular weight, functional groups, elemental composition and infrared spectra were examined. Humic substances, dominated...

Grain size analysis data collected by sediment corer and sediment grabber casts in the Chukchi sea from 1986-08-29 to 1987-10-07 (NODC Accession 9500158)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Grain size analysis data were collected by using sediment corer and sediment graber casts in the Chukchi Sea and NW Coast of Alaska by the Chukchi Sea. Data were...

Arctic sea ice a major determinant in Mandt's black guillemot movement and distribution during non-breeding season

Science.gov (United States)

Divoky, G.J.; Douglas, David C.; Stenhouse, I. J.

2016-01-01

Mandt's black guillemot (Cepphus grylle mandtii) is one of the few seabirds associated in all seasons with Arctic sea ice, a habitat that is changing rapidly. Recent decreases in summer ice have reduced breeding success and colony size of this species in Arctic Alaska. Little is known about the species' movements and distribution during the nine month non-breeding period (September–May), when changes in sea ice extent and composition are also occurring and predicted to continue. To examine bird movements and the seasonal role of sea ice to non-breeding Mandt's black guillemots, we deployed and recovered (n = 45) geolocators on individuals at a breeding colony in Arctic Alaska during 2011–2015. Black guillemots moved north to the marginal ice zone (MIZ) in the Beaufort and Chukchi seas immediately after breeding, moved south to the Bering Sea during freeze-up in December, and wintered in the Bering Sea January–April. Most birds occupied the MIZ in regions averaging 30–60% sea ice concentration, with little seasonal variation. Birds regularly roosted on ice in all seasons averaging 5 h d−1, primarily at night. By using the MIZ, with its roosting opportunities and associated prey, black guillemots can remain in the Arctic during winter when littoral waters are completely covered by ice.

First Indo-Pacific fish species from the Black Sea coast of Turkey: Shrimp scad Alepes djedaba (Forsskål, 1775 (Carangidae

Directory of Open Access Journals (Sweden)

Cemal Turan

2017-11-01

Full Text Available One specimen of shrimp scad Alepes djedaba (Forsskål, 1775 was caught by using fish net at a depth of 30 m on 11 October 2017 from Sinop Bay, the West Black Sea. With the present study, A. djedaba is first lessepsian fish species in the Black Sea coast of Turkey. The migration of IndoPacific species to the Black Sea indicate that climate change is getting an important issue both for marine biodiversity and fisheries in the Black Sea.

Modelling of migration of radionuclides and trace elements between the components of the Black Sea ecosystems

International Nuclear Information System (INIS)

Egorov, V.N.

1999-01-01

This report considers peculiarities of the mathematical description of radionuclides migration between water environment and biotic and abiotic components of the Black Sea ecosystems at different periods of averaging, from the time scale of metabolic processes, taking place in hydrobionts, to the large-scale description of radionuclides migration in the Black Sea

An Introduction to the Black Sea Ecology

Science.gov (United States)

2001-01-01

genus related to the Black Sea Cystoseira) are transported away from the Gulf of Mexico by the Gulf Stream to the northeast and are retained by the...social and economic consequences are not less harmful. It is enough to name the cases of epidemics of cholera and other gastrointestinal infections...seawater, are also found Salmonella, cholera’s vibrios , helmint’s eggs, viruses and other pathogenic organisms which are usually common in insufficiently

Microbial-meiofaunal interrelationships in coastal sediments of the Red Sea.

Science.gov (United States)

El-Serehy, Hamed A; Al-Rasheid, Khaled A; Al-Misned, Fahad A; Al-Talasat, Abdul Allah R; Gewik, Mohamed M

2016-05-01

Population density and biomass of bacteria and meiofauna were investigated seasonally in the sediments of the north-western bank of Red Sea. Samples of sediments were collected seasonally from three different stations to determine microphytobenthic biomass (chlorophyll a), protein, lipid, carbohydrate, and total organic matter concentrations. These investigations revealed that microbial components tended to increase their dominancy, whereas sensitive meiofauna were extremely reduced during the entire study period. Thus a very low density of the total meiofauna (with an annual average of 109 ± 26 ind./10 cm(2)) was recorded whilst the benthic microbial population densities exhibited higher values (ranging from 0.31 ± 0.02 × 10(8) to 43.67 ± 18.62 × 10(8)/g dry sediment). These changes in the relative importance analysis of benthic microbial components versus meiofaunal ones seem to be based on the impact of organic matter accumulation on the function and structure of these benthic communities. Proteins, lipids and carbohydrates showed very low concentration values, and the organic matter mostly consisted of carbohydrates, reflecting lower nutritional values for benthic fauna in general and meiofauna in particular. The distribution of microbial and meiofaunal communities seems to be dependent on the quality of the organic matter rather than on its quantity. Total organic matter concentrations varied between 5.8 and 7.6 mg/g, with organic carbon accounting for only 32% of the total organic matter. Chlorophyll a attained very low values, fluctuating between 0.11 and 0.56 μg/g, indicating the oligotrophy of the studied area. The very low concentration of chlorophyll a in the Red Sea sediment suggests that the sedimentary organic matter, heterotrophic bacteria and/or protozoa constitute an alternative resource that is consumed by meiofauna when algae are less abundant. Protozoa, therefore, represent the "missing link in bacteria-meiofauna interaction

Biogenic Properties of Deep Waters from the Black Sea Reduction (Hydrogen Sulphide) Zone for Marine Algae

OpenAIRE

Polikarpov, Gennady G.; Lazorenko, Galina Е.; Тereschenko, Natalya N.

2015-01-01

Abstract Generalized data of biogenic properties investigations of the Black Sea deep waters from its reduction zone for marine algae are presented. It is shown on board and in laboratory that after pre-oxidation of hydrogen sulphide by intensive aeration of the deep waters lifted to the surface of the sea, they are ready to be used for cultivation of the Black Sea unicellular, planktonic, and multicellular, benthic, algae instead of artificial medium. Naturally balanced micro- and macroeleme...

Assessment of sediment contamination by spermiotoxicity and embryotoxicity bioassays with sea urchins (Paracentrotus lividus) and oysters (Crassostrea gigas).

Science.gov (United States)

Geffard, O; Budzinski, H; Augagneur, S; Seaman, M N; His, E

2001-07-01

Gametes (sperm) and fertilized eggs (embryos) of the Mediterranean sea urchin, Paracentrotus lividus, and the Japanese oyster, Crassostrea gigas, were used to investigate the toxicity of two marine sediments, one polluted by polycyclic aromatic hydrocarbons (PAH) and the other by heavy metals. The sediment samples were freeze-dried for storage, and three different treatments were used for analysis: whole sediment, unfiltered elutriate, and filtered elutriate. The two sediments were toxic to sea urchin spermatozoa but not to oyster spermatozoa, and embryotoxicity was almost always the more sensitive endpoint for toxicity assessment. As a rule, whole sediment was more toxic than the elutriates by nearly two orders of magnitude. With respect to embryotoxicity, the whole sediments and the elutriates of the PAH-contaminated sediment were more toxic to oyster embryos, whereas the elutriates of the sediment polluted by heavy metals had stronger effects on sea urchin embryos. The results confirm that bioassays with Japanese oyster embryos provide a more sensitive appraisal of toxicity in the marine environment than bioassays with other developmental stages. As a whole, Mediterranean sea urchins and Japanese oysters were similar in overall sensitivity and are therefore both equally suited as bioassay organisms, but tests with oysters are more reproducible because of the better performance of the controls.

Synoptic conditions of fine-particle transport to the last interglacial Red Sea-Dead Sea from Nd-Sr compositions of sediment cores

Science.gov (United States)

Palchan, Daniel; Stein, Mordechai; Goldstein, Steven L.; Almogi-Labin, Ahuva; Tirosh, Ofir; Erel, Yigal

2018-01-01

The sediments deposited at the depocenter of the Dead Sea comprise high-resolution archive of hydrological changes in the lake's watershed and record the desert dust transport to the region. This paper reconstructs the dust transport to the region during the termination of glacial Marine Isotope Stage 6 (MIS 6; ∼135-129 ka) and the last interglacial peak period (MIS5e, ∼129-116 ka). We use chemical and Nd and Sr isotope compositions of fine detritus material recovered from sediment core drilled at the deepest floor of the Dead Sea. The data is integrated with data achieved from cores drilled at the floor of the Red Sea, thus, forming a Red Sea-Dead Sea transect extending from the desert belt to the Mediterranean climate zone. The Dead Sea accumulated flood sediments derived from three regional surface cover types: settled desert dust, mountain loess-soils and loess-soils filling valleys in the Dead Sea watershed termed here "Valley Loess". The Valley Loess shows a distinct 87Sr/86Sr ratio of 0.7081 ± 1, inherited from dissolved detrital calcites that originate from dried waterbodies in the Sahara and are transported with the dust to the entire transect. Our hydro-climate and synoptic conditions reconstruction illustrates the following history: During glacial period MIS6, Mediterranean cyclones governed the transport of Saharan dust and rains to the Dead Sea watershed, driving the development of both mountain soils and Valley Loess. Then, at Heinrich event 11, dry western winds blew Saharan dust over the entire Red Sea - Dead Sea transect marking latitudinal expansion of the desert belt. Later, when global sea-level rose, the Dead Sea watershed went through extreme aridity, the lake retreated, depositing salt and accumulating fine detritus of the Valley Loess. During peak interglacial MIS 5e, enhanced flooding activity flushed the mountain soils and fine detritus from all around the Dead Sea and Red Sea, marking a significant "contraction" of the desert belt

Distribution of 137Cs in surface seawater and sediment around Sabahs Sulu-Sulawesi Sea

International Nuclear Information System (INIS)

Mohd Izwan Abdul Aziz; Ahmad Sanadi Abu Bakar; Yii, Mei Wo; Nurrul Assyikeen Jaffary; Zaharudin Ahmad

2010-01-01

The studies on distribution of 137 Cs in surface seawater and sediment around Sabahs Sulu-Sulawesi Sea were carried out during Ekspedisi Pelayaran Saintifik Perdana (EPSP) in July 2009. About sixteen and twenty five sampling locations were identified for surface seawater and sediment respectively in Sabahs Sulu-Sulawesi Sea. Large volumes of seawater samples are collected and co-precipitation technique was employed to concentrate cesium content before known amounts of 134 Cs tracer were added as yield determinant. Grab sampler were used to collect surface sediment sample. The caesium precipitate and sediment were dried and finely ground before counted using gamma-ray spectrometry system at 661 keV. The activity of 137 Cs was found in surface seawater and sediment to be in the range 1.73 Bq/ m 3 to 5.50 Bq/ m 3 and 1.15 Bq/ kg to 4.53 Bq/ kg respectively. (author)

The permeability and consolidation of deep-sea sediments

International Nuclear Information System (INIS)

Schultheiss, P.J.; Gunn, D.E.

1985-01-01

This report presents permeability and consolidation data for a wide range of sediment types. Permeability is one of the two parameters which are needed to directly quantify pore water advection in deep sea sediments and which are being investigated in high-level radioactive waste study areas. While it is desirable that these parameters should be measured in situ it is argued that values of permeability can be measured sufficiently accurately in the laboratory from core samples. Consequently, an apparatus has been developed which enables sediment permeability to be measured at decreasing void ratios during a back-pressured consolidation test. Data presented in this report from over 60 samples have established the major differences in permeability between various sediment types and how permeability changes as a function of burial depth and void ratio. Samples from two study areas in the North Atlantic Ocean, King's Trough Flank (KTF) and Great Meteor East (GME), have been compared with samples of Red Clay (RC) obtained from the NW Pacific Ocean. Results are presented and discussed. (author)

Reactive Fe(II) layers in deep-sea sediments

Science.gov (United States)

König, Iris; Haeckel, Matthias; Drodt, Matthias; Suess, Erwin; Trautwein, Alfred X.

1999-05-01

The percentage of the structural Fe(II) in clay minerals that is readily oxidized to Fe(III) upon contact with atmospheric oxygen was determined across the downcore tan-green color change in Peru Basin sediments. This latent fraction of reactive Fe(II) was only found in the green strata, where it proved to be large enough to constitute a deep reaction layer with respect to the pore water O 2 and NO 3-. Large variations were detected in the proportion of the reactive Fe(II) concentration to the organic matter content along core profiles. Hence, the commonly observed tan-green color change in marine sediments marks the top of a reactive Fe(II) layer, which may represent the major barrier to the movement of oxidation fronts in pelagic subsurface sediments. This is also demonstrated by numerical model simulations. The findings imply that geochemical barriers to pore water oxidation fronts form diagenetically in the sea floor wherever the stage of iron reduction is reached, provided that the sediments contain a significant amount of structural iron in clay minerals.

Origin and abundance of marine litter along sandy beaches of the Turkish Western Black Sea Coast.

Science.gov (United States)

Topçu, Eda N; Tonay, Arda M; Dede, Ayhan; Öztürk, Ayaka A; Öztürk, Bayram

2013-04-01

Beach debris abundance was estimated from surveys on 10 beaches of the Turkish Western Black Sea Coast. Debris was collected from 20 m long transects during four different seasons; sorted and categorized by type, usage and origin. Litter density varied from 0.085 to 5.058 items m(-2). Debris was mainly composed of unidentifiable small size (2-7 cm) plastic pieces and beverage-related litter such as bottles and bottle caps. About half of the labeled litter was of foreign origin, including 25 different countries, 23% of which are in the Black Sea region. The south-western Black Sea Coast seems to receive foreign litter from two main sources: land-based debris from the neighboring countries and seaborne debris due to international shipping. Standardized methodology and indicators need to be designated all over the Black Sea basin in order to quantify and qualify coastal litter pollution, monitor compliance with MARPOL and develop regionally effective mitigation measures. Copyright © 2012 Elsevier Ltd. All rights reserved.

Investigation about the presence of organochlorine pollutants in mussels from the Black Sea, Bulgaria

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Georgieva Stanislava

2016-06-01

Full Text Available The aim of this study was to investigate the presence of polychlorinated biphenyls (PCBs, organochlorine pesticides (HCB, DDT and its metabolites and HCBD in mussels from Bulgarian Black Sea coast. Mussels (Mytilus galloprovincialis are aquatic organisms which are immobile so that the concentration of pollutants should primarily be considered as an indication of local levels of organochlorine compounds. Samples were collected from three areas of Black Sea coast of Bulgaria in summer 2015.

Radiological statuses of Bulgarian black see shore

International Nuclear Information System (INIS)

Totzeva, R.; Badulin, V.; Tenev, J.; Kotova, R.; Ivanova, G.

2013-01-01

Full text: Introduction: In this paper own results of the radiation monitoring of the Black Sea coast - from village Shabla to village Resovo are presented. The study was carried out under a project funded by the BS ERA NET in FP7 of the European Commission, together with the project partners. Materials and Methods: Sampling was conducted in June 2012. 4 seawater samples (including depth of Varna Bay), 12 sand samples, 2 algae samples, 5 bottom sediments samples, 3 surface river water samples, 1 sea fish sample and 1 medical mud sample were examined. The samples were analyzed by gamma spectrometer for determination of the content technogenic and natural radionuclides and by radiochemical methods for defining the specific concentration of strontium- 90. A comparison between the specific activities of radionuclides in sea and river water, in the sands in sea bottom sediments in points and fractions, as well as in green and red algae. Results: The content of Cesium- 137 and Strontium -90 in the tested sea water ranged from 0.0041 (0.0007) to 0,0110 (0,0027) Bq/l and 0.00362 (0.00047) to 0,00409 (0,00049) Bq/l. The concentration of Cesium-137 in river water is ≤ 0,0012 Bq/l. The content of Potassium-40 in the sands is over a wide range from 4.9 (0.7) to 1152 (47) Bq/kg, a testament to their different origins. There is a difference in the contents of the radio-cesium into the upper and the lower fraction of the deep bottom sediment, and the various sampling points. It is clearly distinguished a selectivity of radio-cesium accumulation in red algae and they can be used for bio-indicator. Conclusion: The assessment of the radiological status of the Bulgarian Black Sea coast shows that with the exception of the beach in Vromos all investigated areas are safe from a radiological point of view. All studied coastal marine water as radiological indicators meet the quality standards set by Ordinance H-4/2012

Net removal of dissolved organic carbon in the anoxic waters of the Black Sea

NARCIS (Netherlands)

Margolin, A.R.; Gerringa, L.J.A.; Hansell, D.A.; Rijkenberg, M.J.A.

2016-01-01

Dissolved organic carbon (DOC) concentrations in the deep Black Sea are ~2.5 times higher than found in the globalocean. The two major external sources of DOC are rivers and the Sea of Marmara, a transit point for waters from theMediterranean Sea. In addition, expansive phytoplankton blooms

Innovative eco-friendly bio- solvent for combating sea surface and sedimented oil pollution

Science.gov (United States)

Theodorou, Paraskevas

2017-04-01

The combating of oil spill at sea surface by chemical dispersants accelerates the evaporation and disperse the oil into the water column, where it is broken down by natural processes and/or is sedimented at the sea bottom, especially at near coastal shallow areas, ports and marinas. The usual methodology for cleaning the sedimented oil from the sea bottom is mainly carried out via excavation and dumping of the polluted sediment into deeper sea areas, where the contamination is transferred from one area to another. The eco-friendly bio-solvent MSL Aqua 250 is an innovative new solution based mainly on natural constituents. The action mechanism and the effectiveness of this eco-friendly solvent is based on the high surface tension process. Organic compounds, including hydrocarbons upon coming in contact with MSL Aqua 250 solvent generate a significant surface tension reaction, which is able to alter the organic compounds to liquid form and then to drastically evaporate it. The use of MSL Aqua 250 solvent, both at sea surface and at the bottom, has the following advantages compared to the dispersants: • Efficient solution without transferring the pollution from sea surface to the water column and to the bottom or disturbing the Aquatic Eco System. • Non-Toxic. • Environmentally friendly with a restoration of marine life in the Eco System. • Cost effective. The MSL Aqua 250 solvent has been tested in cooperation with the Cyprus Department of Fisheries and Marine Research and the Technological University of Cyprus and used during the years 2015 and 2016 in marinas and fishing shelters in Cyprus faced oil pollution, with high concentration in the sea water and at the sea bottom of chemical parameters (BOD5, COD, FOG, TKN, TP, TPH), with excellent results.

Sediment Characteristics of Mergui Basin, Andaman Sea based on Multi-proxy Analyses

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Rina Zuraida

2018-02-01

Full Text Available This paper presents the characteristics of sediment from core BS-36 (6°55.85’ S and 96°7.48’ E, 1147.1 m water depth that was acquired in the Mergui Basin, Andaman Sea. The analyses involved megascopic description, core scanning by multi-sensor core logger, and carbonate content measurement. The purpose of this study is to determine the physical and chemical characteristics of sediment to infer the depositional environment. The results show that this core can be divided into 5 lithologic units that represent various environmental conditions. The sedimentation of the bottom part, Units V and IV were inferred to be deposited in suboxic to anoxic bottom condition combined with high productivity and low precipitation. Unit III was deposited during high precipitation and oxic condition due to ocean ventilation. In the upper part, Units II and I occurred during higher precipitation, higher carbonate production and suboxic to anoxic condition. Keywords: sediment characteristics, Mergui Basin, Andaman Sea, suboxic, anoxic, oxic, carbonate content

137Cs dating of laminated sediments in Swedish archipelago areas of the Baltic Sea

International Nuclear Information System (INIS)

Meili, M.; Jonsson, P.; Carman, R.

1998-01-01

In deep off-shore areas of the Baltic Sea, sediment accumulation rates are typically on the order of one or a few millimeters per year, and even less in consolidated sediments, based on laming counts and radiometric dating. In lacustrine and marine basins, the highest sedimentation rates are usually found in the deepest part, since sediments and associated contaminants are known to be gradually 'focused' from shallow to deep areas by resuspension. Accordingly, net sedimentation in coastal areas is usually low or absent due to strong erosion forces. On the other hand, coastal sediments are likely to be important in controlling the fate and turnover of contaminants that are released into coastal waters. Since little is known about the turnover of coastal sediments, in particular for heterogeneous semi-enclosed areas such as the Baltic archipelagos, a study of sediment accumulation rates has been initaited, with a focus on areas where erosion is likely to be minimal. The study is part of a project focusing on the relationship between eutrophication and contaminant cycling (EUCON). 88 sediment cores were collected during summer 1996 from accumulation bottoms of 18 more or less protected bays in archipalgo areas along the swedish coast of the Baltic Sea

Physical and Mechanical Properties of Surface Sediments and methane hydrate-bearing sediments in the Shenhu area of South China Sea

Science.gov (United States)

Jiang, J.; Shen, Z.; Jia, Y.

2017-12-01

Methane hydrates are superior energy resources and potential predisposing factors of geohazard. With the success in China's persistent exploitation of methane hydrates in the Shenhu area of South China Sea for 60 days, there is an increasing demand for detailed knowledge of sediment properties and hazard assessment in this area. In this paper, the physical and mechanical properties of both the surface sediments and methane hydrate-bearing sediments (MHBS) in the exploitation area, the Shenhu area of South China Sea, were investigated using laboratory geotechnical experiments, and triaxial tests were carried out on remolded sediment samples using a modified triaxial apparatus. The results show that sediments in this area are mainly silt with high moisture content, high plasticity, low permeability and low shear strength. The moisture content and permeability decrease while the shear strength increases with the increasing depth. The elastic modulus and peak strength of MHBS increase with the increasing effective confining pressure and higher hydrate saturation. The cohesion increases with higher hydrate saturation while the internal friction angle is barely affected by hydrate saturation. The obtained results demonstrate clearly that methane hydrates have significant impacts on the physical and mechanical properties of sediments and there is still a wide gap in knowledge about MHBS.

Structure of Subsurface Sediments in the Scan Basin (Scotia Sea)

Science.gov (United States)

Schreider, Al. A.; Schreider, A. A.; Sazhneva, A. E.; Galindo-Zaldivar, J.; Ruano, P.; Maldonado, A.; Martos-Martin, Y.; Lobo, F.

2018-01-01

The structure of sediments in the Scotia Sea is used as a basis for reconstructing the geological history of its bottom in the Late Quaternary. The Scan Basin is one of the main elements of the topography of the southern Scotia Sea. Its formation played a considerable role in the fragmentation of the continent, which included the Bruce and Discovery banks. The main parameters of the sediment layer in the Scan Basin have been reconstructed by the present time, but its top part has not been studied. In this work, we analyze the first data obtained on the R/V Gesperidas with the use of a TOPAS PS 18/40 high-resolution seismic profilograph in 2012. Three layers in the subsurface sediments on the bottom of the Scan Basin were specified for the first time. The mean periods of their deposition in the Late Quaternary were determined as 115000 years for the first, 76000 years for the second, and 59 000 years for the third layer from the surface of the bottom. The duration of the total accumulation period of the three layers is about 250000 years.

EU Contribution to Strengthening Regional Development and Cooperation in the Black Sea Basin

Directory of Open Access Journals (Sweden)

Voicu-Dorobanțu Roxana

2017-01-01

Full Text Available EU's agenda had for some time a topic (at least at an idea level about the “strengthening ofcooperation in the Black Sea Region.” It faced an interesting paradox: the lack of (or, in the caseof existence, sub-optimal economic relations between countries in this area, regardless of theirgeographical proximity. The paradoxical situation considered to be mostly due to their differenthistorical and political backgrounds. Therefore, a form of support of regional development in thearea was necessary, as it has been considered in EU's Black Sea Synergy, which encouragescooperation between countries in the Basin while offering a forum for solving common issues andpromoting political and economic reform. Regional cooperation in various areas stems from a highpolitical involvement as the main initiator but requires a strong involvement and participation ofboth civil society and private sector as main drivers of cross-border cooperation. Our paperfocuses, apart from its conceptual research background, on mapping the effective outcomes of theEU initiatives in the area and on providing future perspectives for EU contribution tostrengthening regional development and cooperation in the Black Sea Basin.

THE INFLUENCE OF COASTAL EROSION ON THE DEVELOPMENT OF SOUTHERN ROMANIAN BLACK SEA COASTLINE

OpenAIRE

STAN Mari-Isabella

2014-01-01

The influence of human uses, especially the urbanization and economic activities in the coastal zone have transformed the coastal erosion from a natural phenomenon into a growing problem. The paper aims to analyze and present several important aspects of the influence of the anthropic factors on the coastal erosion along the Romanian Black Sea coast, attempting to answer the following question: what is the framework of development that the coastal zone of the Black Sea could access in order t...

Finding of alien brown macroalgae Chorda tomentosa Lyngb. in the Ukrainian Black Sea coast

OpenAIRE

Minicheva, Galina

2015-01-01

AbstractBrown algae Chorda tomentosa Lyngb. 1819, representative of order Laminariales Mig. 1909, was found in the north-western part of the Black Sea (Ukraine, Odessa Bay, Cape Bolshoi Fontan) in spring 2015. This is a new invasive species in the Black Sea ecosystem and the only representative of brown laminarian algae. Ecological activity of this species is 82.2±4.3 m2·kg-1, that corresponds to the nutrient level of the area where it was found.

The role of local and external factors in determining the interannual sea level variability of the Adriatic and Black Seas during the 20th century.

Science.gov (United States)

Scarascia, Luca; Lionello, Piero

2016-04-01

The Adriatic Sea and the Black Sea are two semienclosed basins connected to the Mediterranean Sea by the Otranto and the Bosporus straits, respectively. This work aims to reconstruction the sea level for both basins in the 20th century and to investigate main sources of interannual variability. Using 7 tide gauge timeseries located along the Adriatic coast and 5 along the Black Sea coast, provided by the PSMSL (Permanent service of mean sea level), a seamless sea level timeseries (1900-2009) has been obtained for each basin on the basis of statistical procedure involving PCA and Least Square Method. The comparison with satellite data in the period 1993 - 2009 confirms that these are reliable representations of the observed sea level for the whole basin, showing a great agreement with a correlation value of 0.87 and 0.72 for Adriatic and Black Sea respectively. The sea level has been decomposed in various contributions in order to analyze the role of the factors responsible for its interannual variability. The annual cycles of the local effect of pressure (inverse barometer effect IB), of the steric effect due to temperature and salinity variation and of the wind effect have been computed. The largest contribute for the Adriatic Sea is due to the wind, whilst inverse barometer effect plays a minor role and the steric effect seems to be almost negligible. For the Black Sea, on the contrary, wind effect is negligible, and the largest source of variability is due to the Danube river, which is estimated from the available discharge data of Sulina (one of the exits of the Danube delta. Steric and IB effects play both a minor role in this basin. A linear regression model, built considering as predictor the SLP gradient identified at large scale after having carried out the correlation analysis, is capable to explain a further percentage of variability (about 20-25%) of the sea level after subtracting all the factors considered above. Finally, residual sea levels show a

The availability of plutonium and americium in Irish Sea sediments for re-dissolution

International Nuclear Information System (INIS)

McDonald, P.; Vives i Batlle, J.; Bousher, A.; Whittall, A.; Chambers, N.

2001-01-01

The availability of plutonium and americium, for re-dissolution from offshore sediments into Irish Sea water, has been examined. Sediments collected from the mud-patch near the Cumbrian coast were characterized in terms of spatial location, particle size, partitioning of radionuclides with respect to physico-chemical bonds and availability of actinides for release into seawater. Sequential extraction investigations revealed that plutonium was predominantly associated with strongly bound sesquioxide and organic complex fractions. Americium was associated mainly with the organic complex fraction, but a significant fraction was in carbonate form. Sediment/water re-dissolution experiments with and without stirring were compared to simulate the effect of disturbing bed sediment. After 1 week, neither set of re-dissolution data provided significant trends between dissolved activity and time. Stirred systems appeared to release 2.5 times more plutonium and americium into seawater than unstirred systems. Measured 239,240Pu and 241Am distribution coefficients (K d values) were both typically approximately 10 5 l kg -1 . 241Am K d values are an order of magnitude lower than previously reported for the north-eastern Irish Sea, but similar to western Irish Sea values. Overall, the fractions of plutonium and americium available for re-dissolution from bed sediment are very low at <0.1%, with proportionally more plutonium being released than americium. These findings lend further support for the extrapolation of laboratory-derived information to environmental conditions

Distribution and sources of polycyclic aromatic hydrocarbons in surface sediments from the Bering Sea and western Arctic Ocean.

Science.gov (United States)

Zhao, Mengwei; Wang, Weiguo; Liu, Yanguang; Dong, Linsen; Jiao, Liping; Hu, Limin; Fan, Dejiang

2016-03-15

To analyze the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) and evaluate their potential ecological risks, the concentrations of 16 PAHs were measured in 43 surface sediment samples from the Bering Sea and western Arctic Ocean. Total PAH (tPAH) concentrations ranged from 36.95 to 150.21 ng/g (dry weight). In descending order, the surface sediment tPAH concentrations were as follows: Canada Basin>northern Chukchi Sea>Chukchi Basin>southern Chukchi Sea>Aleutian Basin>Makarov Basin>Bering Sea shelf. The Bering Sea and western Arctic Ocean mainly received PAHs of pyrogenic origin due to pollution caused by the incomplete combustion of fossil fuels. The concentrations of PAHs in the sediments of the study areas did not exceed effects range low (ERL) values. Copyright © 2016 Elsevier Ltd. All rights reserved.

Natural depuration rate and concentration of cesium-137 radionuclide in black SEA macro algae

International Nuclear Information System (INIS)

Topcuoglu, S.; Kuecuekcezzar, R.; Kut, D.; Esen, N.; Gueven, K.C.

1996-01-01

Cesium-137 concentrations in red, brown and green algae have been studied for the calculation of natural depuration rates. The algae species were collected from the same population of the Black Sea stations during the period of 1986-1995. The natural depuration rates are estimated as biological half-lives. The pattern of depuration results represented by a single component for each algae division. The biological half-lives of 137 Cs in red (Phyllophora nervosa), green (Chaetomorpha linum) and brown (cystoceira barbata) algae are estimated to be 18.5, 21.6 and 29.3 months, respectively. 137 Cs and 40 K activity levels and their ratios in algae species in two stations in Black Sea region of Turkey have been determined during the period of 1990-1995. The results showed that the Sinop region was more contaminated than the Sile region on the Black Sea coast of Turkey from the Chernobyl accident. (author). 10 refs., 2 figs., 2 tabs

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)

Organic Matter Contents and Paleoproductivity Variation Within Late Pleistocene Japan Sea/East Sea Sediments: Results from IODP Expedition 346

Science.gov (United States)

Black, H. D.; Anderson, W. T., Jr.

2017-12-01

Inorganic and organic matter concentrations as well as the stable isotopes of nitrogen and organic carbon are presented for continuous sedimentary sequences collected during Integrated Ocean Drilling Program (IODP) Expedition 346 in the Japan Sea/East Sea in 2013. During major glacioeustatic sea level changes, the paleoceanographic conditions within the Japan Sea/East Sea widely vary due to the shallow, narrow straights connecting the sea to surrounding waters limiting an influx of oceanic currents. During glacial sea level low-stands the sea can be nearly isolated, creating a highly-stratified water column and hypoxic to anoxic bottom water conditions. Meanwhile during sea level high-stands, the Tsushima Warm Current (TWC) flows into the sea bringing warmer, nutrient-rich inputs, leading to vertical mixing and oxic conditions. This study aims to better understand the role of orbital cycling within the organic matter and stable isotope contents of these Late Pleistocene sediments. A total of 192 samples were analyzed each for %CaCO3, %TOC, δ13C, %N, and δ15N from two Expedition 346 sampling sites (U1426 and U1427) during the last 430,000 years and statistical analyses were completed using wavelet and time series analyses. Carbonate concentration ranges from 0-44.3%, total organic carbon 0.2 to 6.4%, δ13C -25.8 to -19.6‰, %N 0.04 to 0.4%, and δ15N 3.8 to 13.1‰. These results are well correlated with b* color values of the sediment and generally show increased productivity during interglacial periods, likely through increased vertical mixing and deepwater ventilation, when compared to glacial periods within the Japan Sea/East Sea when the sea may be partially isolated.

Distribution of Technetium-99 in sub-tidal sediments of the Irish Sea

Science.gov (United States)

McCubbin, David; Leonard, Kinson S.; McDonald, Paul; Bonfield, Rachel; Boust, Dominique

2006-03-01

To date, relatively little attention has been given to the accumulation of 99Tc discharged from Sellafield in the subtidal sediments of the Irish Sea. The potential implications for secondary seafood contamination from contaminated sediment has driven the UK Food Standards Agency to commission further research into this pathway. The work reported here reviews existing data and provides new measurements of 99Tc specific activity in surface and sub-surface sediments of the Irish Sea, together with environmental Kd values. The results are used to assess the spatial and temporal evolution of 99Tc in the seabed after 8 years of enhanced Sellafield discharges (between 1994 and 2002), of the aforementioned radionuclide. The information is discussed with reference to other studies, in an attempt to infer the processes controlling 99Tc uptake and release from seabed sediments. The average environmental Kd value for 99Tc in the Irish Sea (1.9×10 3) was more than an order of magnitude greater than the presently recommended value of 10 2 [IAEA, 2004. Sediment distribution coefficients and concentration factors for biota in the marine environment. Technical Report Series No. 422, IAEA, Vienna]. Comparison with results from laboratory studies indicates that the observed distribution may represent metastable binding rather than thermodynamic equilibrium. Activities in surface sediments decreased with increasing distance from Sellafield but were also dependent upon the nature of the underlying substrate, being greater on muddy material. Preliminary measurements of grain-size distribution indicated that the observed variation in activities was probably not due to surface area effects. There is an emerging body of evidence from other studies that indicate the differences were most likely due to variations in redox regimes between the different substrates. Vertical profiles were significantly irregular, probably due to the effects of variable sediment mixing processes. Comparison of

Environmental conditions outweigh geographical contiguity in determining the similarity of nifH-harboring microbial communities in sediments of two disconnected marginal seas

Directory of Open Access Journals (Sweden)

Haixia Zhou

2016-07-01

Full Text Available Ecological evidence suggests that heterotrophic diazotrophs fueled by organic carbon respiration in sediments play an important role in marine nitrogen fixation. However, fundamental knowledge about the identities, abundance, diversity, biogeography and controlling environmental factors of nitrogen-fixing communities in open ocean sediments is still elusive. Surprisingly, little is known also about nitrogen-fixing communities in sediments of the more research-accessible marginal seas. Here we report on an investigation of the environmental geochemistry and putative diazotrophic microbiota in the sediments of Bohai Sea, an eutrophic marginal sea of the western Pacific Ocean. Diverse and abundant nifH gene sequences were identified and sulfate-reducing bacteria were found to be the dominant putative nitrogen-fixing microbes. Community statistical analyses suggested bottom water temperature, bottom water chlorophyll a content (or the covarying turbidity and sediment porewater Eh (or the covarying pH as the most significant environmental factors controlling the structure and spatial distribution of the putative diazotrophic communities, while sediment Hg content, sulfide content and porewater SiO32--Si content were identified as the key environmental factors correlated positively with the nifH gene abundance in Bohai Sea sediments. Comparative analyses between the Bohai Sea and the northern South China Sea identified a significant composition difference of the putative diazotrophic communities in sediments between the shallow-water (estuarine and nearshore and deep-water (offshore and deep-sea environments, and sediment porewater dissolved oxygen content, water depth and in situ temperature as the key environmental factors tentatively controlling the species composition, community structure and spatial distribution of the marginal sea sediment nifH-harboring microbiota. This confirms the ecophysiological specialization and niche differentiation

Pacific Proving Grounds radioisotope imprint in the Philippine Sea sediments

DEFF Research Database (Denmark)

Pittauer, Daniela; Roos, Per; Qiao, Jixin

2018-01-01

Radionuclide concentrations were studied in sediment cores taken at the continental slope of the Philippine Sea off Mindanao Island in the equatorial Western Pacific. High resolution deposition records of anthropogenic radionuclides were collected at this site. Excess 210Pb together with excess 2...

Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

Science.gov (United States)

Ciobanu, M.-C.; Rabineau, M.; Droz, L.; Révillon, S.; Ghiglione, J.-F.; Dennielou, B.; Jorry, S.-J.; Kallmeyer, J.; Etoubleau, J.; Pignet, P.; Crassous, P.; Vandenabeele-Trambouze, O.; Laugier, J.; Guégan, M.; Godfroy, A.; Alain, K.

2012-09-01

An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion). Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG), within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG) and Halobacteria) within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria within Proteobacteria phylum, and also members of Bacteroidetes phylum. The second most abundant lineages were Actinobacteria and Firmicutes at the Gulf of Lion site and Chloroflexi at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: Alpha-, Gammaproteobacteria, Firmicutes and Actinobacteria. In molecular surveys, the Betaproteobacteria group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea levee. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence analyses (CCA) showed that the availability of electron acceptors and the quality of electron donors (indicated by age

Chemical Composition of the Graphitic Black Carbon Fraction in Riverine and Marine Sediments at Submicron Scales using Carbon X-ray Spectromicroscopy

International Nuclear Information System (INIS)

Haberstroh, P.; Brandes, J.; Gelinas, Y.; Dickens, A.; Wirick, S.; Cody, G.

2006-01-01

The chemical composition of the graphitic black carbon (GBC) fraction of marine organic matter was explored in several marine and freshwater sedimentary environments along the west coast of North America and the Pacific Ocean. Analysis by carbon x-ray absorption near edge structure (C-XANES) spectroscopy and scanning transmission x-ray microscopy (STXM) show the GBC-fraction of Stillaguamish River surface sediments to be dominated by more highly-ordered and impure forms of graphite, together forming about 80% of the GBC, with a smaller percent of an aliphatic carbon component. Eel River Margin surface sediments had very little highly-ordered graphite, and were instead dominated by amorphous carbon and to a lesser extent, impure graphite. However, the GBC of surface sediments from the Washington State Slope and the Mexico Margin were composed almost solely of amorphous carbon. Pre-anthropogenic, highly-oxidized deep-sea sediments from the open Equatorial Pacific Ocean contained over half their GBC in different forms of graphite as well as highly-aliphatic carbon, low aromatic/highly-acidic aliphatic carbon, low aromatic/highly aliphatic carbon, and amorphous forms of carbon. Our results clearly show the impact of graphite and amorphous C phases in the BC fraction in modern riverine sediments and nearby marine shelf deposits. The pre-anthropogenic Equatorial Pacific GBC fraction is remarkable in the existence of highly-ordered graphite

16S rRNA-based bacterial diversity in the organic-rich sediments underlying oxygen-deficient waters of the eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Divya, B.; Parvathi, A.; LokaBharathi, P.A.; Nair, S.

). Bootstrap analysis was carried out using 1000 iterations. Diversity analysis The clone library of AS-OMZ was compared with those of other anoxic sediments from Gulf of Mexico, North Sea and South China Sea (28, 60 and 87 sequences, respectively.... Figure 2d Bacterial diversity and richness To understand the bacterial diversity and richness of the AS-OMZ sediment clone library, comparisons were made with suboxic sediment clone libraries from South China Sea, North Sea and Gulf of Mexico...

Real-time PCR quantification and diversity analysis of the functional genes aprA and dsrA of sulfate-reducing bacteria in marine sediments of the Peru continental margin and the Black Sea

Directory of Open Access Journals (Sweden)

Axel eSchippers

2011-12-01

Full Text Available A quantitative, real-time PCR (Q-PCR assay for the functional gene adenosine 5´-phosphosulfate reductase (aprA of sulfate-reducing bacteria (SRB was designed. This assay was applied together with described Q-PCR assays for dissimilatory sulfite reductase (dsrA and the 16S rRNA gene of total Bacteria to marine sediments from the Peru margin (0 – 121 meters below seafloor (mbsf and the Black Sea (0 – 6 mbsf. Clone libraries of aprA show that all isolated sequences originate from SRB showing a close relationship to aprA of characterised species or form a new cluster with only distant relation to aprA of isolated SRB. Below 40 mbsf no aprA genes could be amplified. This finding corresponds with results of the applied new Q-PCR assay for aprA. In contrast to the aprA the dsrA gene could be amplified up to sediment depths of 121 mbsf. Even in such an extreme environment a high diversity of this gene was detected. The 16S rRNA gene copy numbers of total Bacteria were much higher than those of the functional genes at all sediment depths and used to calculate the proportion of SRB to the total Bacteria. The aprA and dsrA copy numbers comprised in average 0.5 - 1 % of the 16S rRNA gene copy numbers of total Bacteria in the sediments up to a depth of ca. 40 mbsf. Depth profiles of the aprA and dsrA copy numbers were almost equal for all sites. Gene copy numbers decreased concomitantly with depth from around 108 / g sediment close to the sediment surface to less than 105 / g sediment at 5 mbsf. In the zone without detectable sulfate in the pore water from ca. 40 – 121 mbsf (Peru margin ODP site 1227, only dsrA (but not aprA was detected with copy numbers of less than 104 / g sediment, comprising ca. 14 % of the 16S rRNA gene copy numbers of total Bacteria. In this zone sulfate might be provided for SRB by anaerobic sulfide oxidation.

The effect of snow/sea ice type on the response of albedo and light penetration depth (e-folding depth to increasing black carbon

Directory of Open Access Journals (Sweden)

A. A. Marks

2014-09-01

Full Text Available The optical properties of snow/sea ice vary with age and by the processes they were formed, giving characteristic types of snow and sea ice. The response of albedo and light penetration depth (e-folding depth to increasing mass ratio of black carbon is shown to depend on the snow and sea ice type and the thickness of the snow or sea ice. The response of albedo and e-folding depth of three different types of snow (cold polar snow, wind-packed snow and melting snow and three sea ice (multi-year ice, first-year ice and melting sea ice to increasing mass ratio of black carbon is calculated using a coupled atmosphere–snow/sea ice radiative-transfer model (TUV-snow, over the optical wavelengths of 300–800 nm. The snow and sea ice types are effectively defined by a scattering cross-section, density and asymmetry parameter. The relative change in albedo and e-folding depth of each of the three snow and three sea ice types with increasing mass ratio of black carbon is considered relative to a base case of 1 ng g−1 of black carbon. The relative response of each snow and sea ice type is intercompared to examine how different types of snow and sea ice respond relative to each other. The relative change in albedo of a melting snowpack is a factor of four more responsive to additions of black carbon compared to cold polar snow over a black carbon increase from 1 to 50 ng g−1, while the relative change in albedo of a melting sea ice is a factor of two more responsive to additions of black carbon compared to multi-year ice for the same increase in mass ratio of black carbon. The response of e-folding depth is effectively not dependent on snow/sea ice type. The albedo of sea ice is more responsive to increasing mass ratios of black carbon than snow.

Special data base of Informational - Computational System 'INM RAS - Black Sea' for solving inverse and data assimilation problems

Science.gov (United States)

Zakharova, Natalia; Piskovatsky, Nicolay; Gusev, Anatoly

2014-05-01

Development of Informational-Computational Systems (ICS) for data assimilation procedures is one of multidisciplinary problems. To study and solve these problems one needs to apply modern results from different disciplines and recent developments in: mathematical modeling; theory of adjoint equations and optimal control; inverse problems; numerical methods theory; numerical algebra and scientific computing. The above problems are studied in the Institute of Numerical Mathematics of the Russian Academy of Science (INM RAS) in ICS for personal computers. In this work the results on the Special data base development for ICS "INM RAS - Black Sea" are presented. In the presentation the input information for ICS is discussed, some special data processing procedures are described. In this work the results of forecast using ICS "INM RAS - Black Sea" with operational observation data assimilation are presented. This study was supported by the Russian Foundation for Basic Research (project No 13-01-00753) and by Presidium Program of Russian Academy of Sciences (project P-23 "Black sea as an imitational ocean model"). References 1. V.I. Agoshkov, M.V. Assovskii, S.A. Lebedev, Numerical simulation of Black Sea hydrothermodynamics taking into account tide-forming forces. Russ. J. Numer. Anal. Math. Modelling (2012) 27, No.1, pp. 5-31. 2. E.I. Parmuzin, V.I. Agoshkov, Numerical solution of the variational assimilation problem for sea surface temperature in the model of the Black Sea dynamics. Russ. J. Numer. Anal. Math. Modelling (2012) 27, No.1, pp. 69-94. 3. V.B. Zalesny, N.A. Diansky, V.V. Fomin, S.N. Moshonkin, S.G. Demyshev, Numerical model of the circulation of Black Sea and Sea of Azov. Russ. J. Numer. Anal. Math. Modelling (2012) 27, No.1, pp. 95-111. 4. Agoshkov V.I.,Assovsky M.B., Giniatulin S. V., Zakharova N.B., Kuimov G.V., Parmuzin E.I., Fomin V.V. Informational Computational system of variational assimilation of observation data "INM RAS - Black sea"// Ecological

Distribution of 137Cs in samples of ocean bottom sediments of the baltic sea in 1982-1983

International Nuclear Information System (INIS)

Gedenov, L.I.; Flegontov, V.M.; Ivanova, L.M.; Kostandov, K.A.

1986-01-01

The concentration of Cs-137 in samples of ocean bottom sediments picked up in 1979 in the Gulf of Finland with a geological nozzle pipe varied within a wide interval of values. The results could indicate nonuniformity of the Cs-137 distribution in ocean bottom sediments as well as the penetration of significant amounts of Cs-137 to large depths. The main error resulted from the sampling technique employed because the upper part of the sediment could be lost. In 1982, a special ground-sampling device, with which the upper layer of sediments in the water layer close to the ocean bottom could be sampled, was tested in the Gulf of Finland and the Northeastern part of the Baltic Sea. The results of a layerwise determination of the Cs-137 concentration in samples of ocean bottom sediments of the Gulf of Finland and of the Baltic Sea are listed. The new soil-sampling device for picking samples of ocean sediments of undisturbed stratification will allow a correct determination of the radionuclide accumulation in the upper layers of ocean bottom sediments in the Baltic Sea

Optical properties of sea ice doped with black carbon – an experimental and radiative-transfer modelling comparison

Directory of Open Access Journals (Sweden)

A. A. Marks

2017-12-01

Full Text Available Radiative-transfer calculations of the light reflectivity and extinction coefficient in laboratory-generated sea ice doped with and without black carbon demonstrate that the radiative-transfer model TUV-snow can be used to predict the light reflectance and extinction coefficient as a function of wavelength. The sea ice is representative of first-year sea ice containing typical amounts of black carbon and other light-absorbing impurities. The experiments give confidence in the application of the model to predict albedo of other sea ice fabrics. Sea ices,  ∼  30 cm thick, were generated in the Royal Holloway Sea Ice Simulator ( ∼  2000 L tanks with scattering cross sections measured between 0.012 and 0.032 m2 kg−1 for four ices. Sea ices were generated with and without  ∼  5 cm upper layers containing particulate black carbon. Nadir reflectances between 0.60 and 0.78 were measured along with extinction coefficients of 0.1 to 0.03 cm−1 (e-folding depths of 10–30 cm at a wavelength of 500 nm. Values were measured between light wavelengths of 350 and 650 nm. The sea ices generated in the Royal Holloway Sea Ice Simulator were found to be representative of natural sea ices. Particulate black carbon at mass ratios of  ∼  75,  ∼  150 and  ∼  300 ng g−1 in a 5 cm ice layer lowers the albedo to 97, 90 and 79 % of the reflectivity of an undoped clean sea ice (at a wavelength of 500 nm.

Artificial radionuclides 90Sr and 241Am in the sediments of the Baltic Sea: Total and spatial inventories and some temporal trends

International Nuclear Information System (INIS)

Hutri, Kaisa-Leena; Mattila, Jukka; Ikäheimonen, Tarja Tuulikki; Vartti, Vesa-Pekka

2013-01-01

Highlights: • The inventories of 137 Sr and 241 Am in the Baltic Sea is studied. • About 20 sediment cores around the Baltic Sea were analyzed. • The results show that 90 Sr distribution is uneven and effected by the Chernobyl fallout. • 241 Am is more evenly distributed in the sediments. • The Baltic Sea is the most contaminated sea with respect to 137 Cs in sediments. -- Abstract: The Baltic Sea was contaminated by radioactivity following global nuclear fallout and later by the Chernobyl accident. Despite the decrease of radioactivity caused by radioactive decay, radionuclides have a prolonged residence time in the water of the Baltic Sea due to slow water exchange and relatively rapid sedimentation. Very little is known about the amounts or spatial differences of 90 Sr and 241 Am in the Baltic Sea sediments. In this study, 20 sediment cores taken around the Baltic Sea were investigated to estimate inventories of these radionuclides. The rough results show that the Chernobyl fallout added the amount of 90 Sr in the same areas where the increase of 137 Cs can be detected, whereas this is not the case for 241 Am which is more evenly distributed in the sea bottom. In addition, local differences occur in the concentrations. These results are an important amendment to the radioactivity baseline of the Baltic Sea

77 FR 28305 - Temporary Rule To Delay Start Date of 2012-2013 South Atlantic Black Sea Bass Commercial Fishing...

Science.gov (United States)

2012-05-14

.... 120501426-2426-01] RIN 0648-BB98 Temporary Rule To Delay Start Date of 2012-2013 South Atlantic Black Sea... this temporary rule to delay the start date of the 2012-2013 fishing season for the commercial black... temporary rule delays the start date of the 2012-2013 commercial fishing season for black sea bass from June...

Spatial and temporal variability of sediment accumulation rates on two tidal flats in Lister Dyb tidal basin, Wadden Sea, Denmark

DEFF Research Database (Denmark)

Madsen, Anni Tindahl; Murray, Andrew S.; Andersen, Thorbjørn Joest

2010-01-01

Depositional processes in intertidal areas are determined both by changes in sea-level and sediment supply. It is known on a millennial timescale that sedimentation normally keeps pace with sea-level rise in a subsiding tidal basin. However, little is known about whether the sedimentation can kee...

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.

Polyporus squamosus (Huds. Fr. in the Black Sea Region

Directory of Open Access Journals (Sweden)

Sanem Bulam

2018-03-01

Full Text Available Polyporus squamosus (Huds. Fr., also named as Aladana, Peri Semeri, Pullu Mantar in varying by localities of Turkey, is an edible wild mushroom species widely existed in the mycobiota of the Black Sea Region. It has not been sold in the local markets. The public recognition of this mushroom may change locally in the Black Sea Region. It is widely consumed by the people in some parts of the region. It is usually appeared in the nature during May-September on the logs, dead and living trunks of the deciduous trees. Following the rainy period, it grows so fast and can produce a few kilograms fruit body within a short period. It is delicious and precious as much as meat for the nutritional value, especially during early growth stage. In this review, general knowledge on the morphological and ecological characteristics, nutritional value and medicinal properties of P. squamosus mushroom and some study results on the domestication of this mushroom have been presented in order to improve the public awareness and its consumption.

Horsemanship of ancient armies of Northern Black Sea region

Directory of Open Access Journals (Sweden)

K. M. Kolesnykov

2015-06-01

Full Text Available This article deal with the description, analysis and generalization of features of organization and tactics of cavalry of the army ancient states of the Northern Black Sea region: Olbia, Chersonese, Bosporus. Author sure that the foundation of the armed forces of these states was a civil militia – free, economically independent landowners, endowed with the broadest volume of political and social rights men – full citizens. Bosporus kings have attracted a significant number of hired troops that held by the royal treasury income and special direct tax. The cavalry is interacted with heavily armed infantry contingents – hoplites or swordsman­ thyureoforoi. The contingents of lightweight (arrow­toxots and heavy (akontists and spearmen cavalry were presented as part of ancient armies of the Northern Black Sea Region in Classical and Hellenistic periods. In the Roman period on the Bosporus fixed formation units of cathafractarian cavalry. The weapons and tactics of the Sarmatian nomadic nobility (Aspurhianian, Sirak, Aorsy and more were served as a model for Bosporus cataphractarian horsemen.

Distribution and Composition of Thiotrophic Mats in the Hypoxic Zone of the Black Sea (150-170 m Water Depth, Crimea Margin).

Science.gov (United States)

Jessen, Gerdhard L; Lichtschlag, Anna; Struck, Ulrich; Boetius, Antje

2016-01-01

At the Black Sea chemocline, oxygen- and sulfide-rich waters meet and form a niche for thiotrophic pelagic bacteria. Here we investigated an area of the Northwestern Black Sea off Crimea close to the shelf break, where the chemocline reaches the seafloor at around 150-170 m water depth, to assess whether thiotrophic bacteria are favored in this zone. Seafloor video transects were carried out with the submersible JAGO covering 20 km(2) on the region between 110 and 200 m depth. Around the chemocline we observed irregular seafloor depressions, covered with whitish mats of large filamentous bacteria. These comprised 25-55% of the seafloor, forming a belt of 3 km width around the chemocline. Cores from the mats obtained with JAGO showed higher accumulations of organic matter under the mats compared to mat-free sediments. The mat-forming bacteria were related to Beggiatoa-like large filamentous sulfur bacteria based on 16S rRNA sequences from the mat, and visual characteristics. The microbial community under the mats was significantly different from the surrounding sediments and enriched with taxa affiliated with polymer degrading, fermenting and sulfate reducing microorganisms. Under the mats, higher organic matter accumulation, as well as higher remineralization and radiotracer-based sulfate reduction rates were measured compared to outside the mat. Mat-covered and mat-free sediments showed similar degradability of the bulk organic matter pool, suggesting that the higher sulfide fluxes and subsequent development of the thiotrophic mats in the patches are consequences of the accumulation of organic matter rather than its qualitative composition. Our observations suggest that the key factors for the distribution of thiotrophic mat-forming communities near to the Crimean shelf break are hypoxic conditions that (i) repress grazers, (ii) enhance the accumulation and degradation of labile organic matter by sulfate-reducers, and (iii) favor thiotrophic filamentous bacteria

A model of water and sediment balance as determinants of relative sea level rise in contemporary and future deltas

Science.gov (United States)

Tessler, Zachary D.; Vörösmarty, Charles J.; Overeem, Irina; Syvitski, James P. M.

2018-03-01

Modern deltas are dependent on human-mediated freshwater and sediment fluxes. Changes to these fluxes impact delta biogeophysical functioning and affect the long-term sustainability of these landscapes for human and for natural systems. Here we present contemporary estimates of long-term mean sediment balance and relative sea level rise across 46 global deltas. We model scenarios of contemporary and future water resource management schemes and hydropower infrastructure in upstream river basins to explore how changing sediment fluxes impact relative sea level rise in delta systems. Model results show that contemporary sediment fluxes, anthropogenic drivers of land subsidence, and sea level rise result in delta relative sea level rise rates that average 6.8 mm/y. Assessment of impacts of planned and under-construction dams on relative sea level rise rates suggests increases on the order of 1 mm/y in deltas with new upstream construction. Sediment fluxes are estimated to decrease by up to 60% in the Danube and 21% in the Ganges-Brahmaputra-Meghna if all currently planned dams are constructed. Reduced sediment retention on deltas caused by increased river channelization and management has a larger impact, increasing relative sea level rise on average by nearly 2 mm/y. Long-term delta sustainability requires a more complete understanding of how geophysical and anthropogenic change impact delta geomorphology. Local and regional strategies for sustainable delta management that focus on local and regional drivers of change, especially groundwater and hydrocarbon extraction and upstream dam construction, can be highly impactful even in the context of global climate-induced sea level rise.

Changing Sediment Dynamics of a Mature Backbarrier Salt Marsh in Response to Sea-Level Rise and Storm Events

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Mark Schuerch

2018-05-01

Full Text Available Our study analyses the long-term development of a tidal backbarrier salt marsh in the northern German Wadden Sea. The focus lies on the development of the high-lying, inner, mature part of the salt marsh, which shows a striking history of changing sediment dynamics. The analysis of high-resolution old aerial photographs and sampled sediment cores suggests that the mature part of the marsh was shielded by a sand barrier from the open sea for decades. The supply with fine-grained sediments occurred from the marsh inlet through the tidal channels to the inner salt marsh. Radiometric dating (210Pb and 137Cs reveals that the sedimentation pattern changed fundamentally around the early-mid 1980s when the sedimentation rates increased sharply. By analyzing the photographic evidence, we found that the sand barrier was breached during storm events in the early 1980s. As a result, coarse-grained sediments were brought directly through this overwash from the sea to the mature part of the salt marsh and increased the sedimentation rates. We show that the overwash and the channels created by these storm events built a direct connection to the sea and reduced the distance to the sediment source which promoted salt marsh growth and a supply with coarse-grained sediments. Consequently, the original sediment input from the tidal channels is found to play a minor role in the years following the breach event. The presented study showcases the morphological development of a mature marsh, which contradicts the commonly accepted paradigm of decreasing sedimentation rates with increasing age of the marsh. We argue that similar trends are likely to be observed in other backbarrier marshes, developing in the shelter of unstabilized sand barriers. It further highlights the question of how resilient these salt marshes are toward sea level rise and how extreme storm events interfere in determining the resilience of a mature salt marsh.

Marine environmental assessment of the Black Sea region ministerial meeting. Opening statement, Monaco, 5 October 1998

International Nuclear Information System (INIS)

ElBaradei, M.

1998-01-01

The document reproduces the text of the Opening Statement of the Director General of the IAEA at the Ministerial Meeting on Marine Environmental Assessment of the Black Sea Region, held in Monaco, on 5 October 1998. The Director General emphasized the contribution of the IAEA, mainly through its Technical Co-operation Programme, in strengthening the international co-operation in marine environmental assessment of the Black Sea region

Palaeoecology and geoarchaeology of the Varna Lake, northern Bulgarian Black Sea coast

Directory of Open Access Journals (Sweden)

Mariana FILIPOVA-MARINOVA

2014-11-01

Full Text Available The coastal lakes are rich sources of biostratigraphic information that is very useful in palaeoecological reconstructions of climate changes and human impact on the natural vegetation. This information is of great importance for the archaeological descriptions of submerged praehistorical settlements found in the northern Bulgarian Black sea area. There are 4 archaeological sites in this area that have been palynologically studied for the last 30 years: the Durankulak Lake, the Shabla-Ezeretz Lake system, the Lake Bolata, as well as the Varna-Beloslav Lake system. Because of the lack of AMS radiocarbon dates for these sites, it was not possible to correlate adequately all palaeoenvironmental results with the available archaeological chronology.Aimed to receive additional information on the Holocene vegetation dynamics and lake level changes, as well as on the anthropogenic impact during the Late Eneolithic and Early Bronze Age, the high-resolution spore-pollen analysis of AMS dated laminated sediments from a new Core 3 – Varna Lake was combined with analyses of dinoflagellate cysts, acritarchs, and other non-pollen palynomorphs.The location of the core is close to several sites of submerged praehistorical settlements and the Varna Late Eneolithic (Chalcolithic Necropolis, which is famous with the oldest hand-made gold treasure in the Worlds, and permits the palaeoenvironmental correlations of obtained results with available archaeological and geochronological data. The core is 995 cm long, but its palynologically investigated length is 870 cm. It contains dark grey clay and laminated sediments (varves. Seven samples of sediments were submitted for radiocarbon dating to the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS Facility of Woods Hole Oceanographic Institution (WHOI. The dates have been calibrated using the program CALIB version 6.1.0 of using the IntCal09 curve. An Age Model for the sedimentation rate was created by the

Fungal diversity in deep-sea sediments of a hydrothermal vent system in the Southwest Indian Ridge

Science.gov (United States)

Xu, Wei; Gong, Lin-feng; Pang, Ka-Lai; Luo, Zhu-Hua

2018-01-01

Deep-sea hydrothermal sediment is known to support remarkably diverse microbial consortia. In deep sea environments, fungal communities remain less studied despite their known taxonomic and functional diversity. High-throughput sequencing methods have augmented our capacity to assess eukaryotic diversity and their functions in microbial ecology. Here we provide the first description of the fungal community diversity found in deep sea sediments collected at the Southwest Indian Ridge (SWIR) using culture-dependent and high-throughput sequencing approaches. A total of 138 fungal isolates were cultured from seven different sediment samples using various nutrient media, and these isolates were identified to 14 fungal taxa, including 11 Ascomycota taxa (7 genera) and 3 Basidiomycota taxa (2 genera) based on internal transcribed spacers (ITS1, ITS2 and 5.8S) of rDNA. Using illumina HiSeq sequencing, a total of 757,467 fungal ITS2 tags were recovered from the samples and clustered into 723 operational taxonomic units (OTUs) belonging to 79 taxa (Ascomycota and Basidiomycota contributed to 99% of all samples) based on 97% sequence similarity. Results from both approaches suggest that there is a high fungal diversity in the deep-sea sediments collected in the SWIR and fungal communities were shown to be slightly different by location, although all were collected from adjacent sites at the SWIR. This study provides baseline data of the fungal diversity and biogeography, and a glimpse to the microbial ecology associated with the deep-sea sediments of the hydrothermal vent system of the Southwest Indian Ridge.

Problems and Possible Solutions Concerning Radiocarbon Dating of Surface Marine Sediments, Ross Sea, Antarctica

Science.gov (United States)

Andrews, John T.; Domack, Eugene W.; Cunningham, Wendy L.; Leventer, Amy; Licht, Kathy J.; Jull, A. J. Timothy; DeMaster, David J.; Jennings, Anne E.

1999-09-01

Radiocarbon accelerator mass spectrometric (AMS) dates on the acid-insoluble fraction from 38 core tops from the western Ross Sea, Antarctica, are used to address these questions: (1) What are the apparent ages of sediments at or close to the present sediment/water interface? (2) Is there a statistically significant pattern to the spatial distribution of core top ages? and (3) Is there a "correction factor" that can be applied to these age determinations to obtain the best possible Holocene (downcore) chronologies? Ages of core top sediments range from 2000 to 21,000 14C yr B.P. Some "old" core top dates are from piston cores and probably represent the loss of sediment during the coring process, but some core top samples >6000 14C yr B.P. may represent little or no Holocene deposition. Four possible sources of variability in dates ≤6000 14C yr B.P. (n = 28) are associated with (1) different sample preparation methods, (2) different sediment recovery systems, (3) different geographic regions, and (4) within-sample lateral age variability. Statistical analysis on an a posteriori design indicates that geographic area is the major cause of variability; there is a difference in mean surface sediment age of nearly 2000 yr between sites in the western Ross Sea and sites east of Ross Bank in south-central Ross Sea. The systematic variability in surface age between areas may be attributed to: (a) variable sediment accumulation rates (SAR) (surface age is inversely related to SAR), (b) differences in the percentage of reworked (dead) carbon between each area, and/or (c) differences in the CO2 exchange between the ocean and the atmosphere.

Black Sea impact on its west-coast land surface temperature

Science.gov (United States)

Cheval, Sorin; Constantin, Sorin

2018-03-01

This study investigates the Black Sea influence on the thermal characteristics of its western hinterland based on satellite imagery acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS). The marine impact on the land surface temperature (LST) values is detected at daily, seasonal and annual time scales, and a strong linkage with the land cover is demonstrated. The remote sensing products used within the study supply LST data with complete areal coverage during clear sky conditions at 1-km spatial resolution, which is appropriate for climate studies. The sea influence is significant up to 4-5 km, by daytime, while the nighttime influence is very strong in the first 1-2 km, and it gradually decreases westward. Excepting the winter, the daytime temperature increases towards the plateau with the distance from the sea, e.g. with a gradient of 0.9 °C/km in the first 5 km in spring or with 0.7 °C/km in summer. By nighttime, the sea water usually remains warmer than the contiguous land triggering higher LST values in the immediate proximity of the coastline in all seasons, e.g. mean summer LST is 19.0 °C for the 1-km buffer, 16.6 °C for the 5-km buffer and 16.0 °C for the 10-km buffer. The results confirm a strong relationship between the land cover and thermal regime in the western hinterland of the Black Sea coast. The satellite-derived LST and air temperature values recorded at the meteorological stations are highly correlated for similar locations, but the marine influence propagates differently, pledging for distinct analysis. Identified anomalies in the general observed trends are investigated in correlation with sea surface temperature dynamics in the coastal area.

The effects of additional black carbon on the albedo of Arctic sea ice: variation with sea ice type and snow cover

OpenAIRE

A. A. Marks; M. D. King

2013-01-01

The response of the albedo of bare sea ice and snow-covered sea ice to the addition of black carbon is calculated. Visible light absorption and light-scattering cross-sections are derived for a typical first-year and multi-year sea ice with both "dry" and "wet" snow types. The cross-sections are derived using data from a 1970s field study that recorded both reflectivity and light penetration in Arctic sea ice and snow overlying sea ice. The variation of absorption cross-section ov...

Exploration of biodegradation mechanisms of black carbon-bound nonylphenol in black carbon-amended sediment

International Nuclear Information System (INIS)

Cheng, Guanghuan; Sun, Mingyang; Ge, Xinlei; Xu, Xinhua; Lin, Qi; Lou, Liping

2017-01-01

The present study aimed to investigate biodegradation mechanisms of black carbon (BC)-bound contaminants in BC-amended sediment when BC was applied to control organic pollution. The single-point Tenax desorption technique was applied to track the species changes of nonylphenol (NP) during biodegradation process in the rice straw carbon (RC)-amended sediment. And the correlation between the biodegradation and desorption of NP was analyzed. Results showed that microorganisms firstly degraded the rapid-desorbing NP (6 h Tenax desorption) in RC-amended sediment. The biodegradation facilitated the desorption of slow-desorbing NP, which was subsequently degraded as well (192 h Tenax desorption). Notably, the final amount of NP degradation was greater than that of NP desorption, indicating that absorbed NP by RC amendment can be degraded by microorganisms. Finally, the residual NP amount in RC-amended sediment was decided by RC content and its physicochemical property. Moreover, the presence of the biofilm was observed by the confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) so that microorganisms were able to overcome the mass transfer resistance and directly utilized the absorbed NP. Therefore, single-point Tenax desorption alone may not be an adequate basis for the prediction of the bioaccessibility of contaminants to microorganisms or bioremediation potential in BC-amended sediment. - Highlights: • Biodegradation mechanism of RC-bound NP in sediment was examined. • The microbe prioritized the degradation of NP in desorption fraction. • The microbe formed the biofilm to directly degrade part of non-desorbable NP. • Residual NP amount was decided by RC content and physicochemical property. • Quantifying biodegradation by bioavailability will underestimate the actual outcomes. - The microbes directly degrade the non-desorbable NP bound to amended RC, so quantifying the biodegradation only by desorption will underestimate the

Russian Build-Up on the Black Sea and Recommendations for U.S.-NATO Counter-Strategy

Science.gov (United States)

2017-03-01

the Mediterranean and the greater world by Russia. In 1841 in London the great powers of Europe—Russia, United Kingdom, France , Austria and Prussia—as...next decade, becoming one of the causes of the Crimean War (1853–1856).4 In 1850 some disputes arose between the Orthodox and the Roman Catholic ...the Turkish fleet near Sinop, in the Black Sea. France , the British Empire, and Sardinia sided with the Ottomans. War was fought on the Black Sea as

Distribution and characteristics of organic micropollutants in surface sediments from Bohai Sea

International Nuclear Information System (INIS)

Liu Wenxin; Chen Jianglin; Lin Xiumei; Tao Shu

2006-01-01

Spatial distribution and compositional characteristics of PAHs, DDTs and PCBs in surface sediments from Bohai Sea were investigated. Proportion of LMW PAHs at Jinzhou Bay was significant, due probably to the petrogenic sources from neighboring oil wells and plants, while HMW PAHs were dominant in the other sea areas, inferred pyrogenic origins mainly from coal or petroleum combustion. The average ERL quotient for the PAH species in Qinhuangdao and Liaodong Bay indicated relatively stronger potential ecological risk. The concentration ratios of DDT to metabolites (DDD + DDE) exceeded 1.0 in the coastal areas of Qinhuangdao, Liaodong Bay and Bohai Bay, demonstrated some recent inputs of DDT nearby, and DDD as the major degradation product. The concentrations of PCBs were generally low, however, the contents of DDTs were greater than the ERL guidelines in the coastal areas of Qinhuangdao, Liaodong Bay and Bohai Bay, and suggested the potential ecological risk. - The recent inputs of DDT in surface sediments at some sites of Bohai Sea indicated potential ecological risk

Exchanges between the shelf and the deep Black Sea: an integrated analysis of physical mechanisms

Science.gov (United States)

Shapiro, Georgy; Wobus, Fred; Zatsepin, Andrei; Akivis, Tatiana; Zhou, Feng

2017-04-01

This study provides an integrated analysis of exchanges of water, salt and heat between the north-western Black Sea shelf and the deep basin. Three contributing physical mechanisms are quantified, namely: Ekman drift, transport by mesoscale eddies at the edge of the NW Black Sea shelf and non-local cascading assisted by the rim current and mesoscale eddies. The semi-enclosed nature of the Black Sea together with its unique combination of an extensive shelf area in the North West and the deep central part make it sensitive to natural variations of fluxes, including the fluxes between the biologically productive shelf and predominantly anoxic deep sea. Exchanges between the shelf and deep sea play an important role in forming the balance of waters, nutrients and pollution within the coastal areas, and hence the level of human-induced eutrophication of coastal waters (MSFD Descriptor 5). In this study we analyse physical mechanisms and quantify shelf-deep sea exchange processes in the Black Sea sector using the NEMO ocean circulation model. The model is configured and optimized taking into account specific features of the Black Sea, and validated against in-situ and satellite observations. The study uses NEMO-BLS24 numerical model which is based on the NEMO codebase v3.2.1 with amendments introduced by the UK Met Office. The model has a horizontal resolution of 1/24×1/24° and a hybrid s-on-top-of-z vertical coordinate system with a total of 33 layers. The horizontal viscosity/diffusivity operator is rotated to reduce the contamination of vertical diffusion/viscosity by large values of their horizontal counterparts. The bathymetry is processed from ETOPO5 and capped to 1550m. Atmospheric forcing for the period 1989-2012 is given by the Drakkar Forcing Set v5.2. For comparison, the NCEP atmospheric forcing also used for 2005. The climatological runoff from 8 major rivers is included. We run the model individually for 24 calendar years without data assimilation. For

Estimation of Sea Level variations with GPS/GLONASS-Reflectometry Technique: Case Study at Stationary Oceanographic Platform in the Black Sea

Science.gov (United States)

Kurbatov, G. A.; Padokhin, A. M.

2017-12-01

In the present work we study GNSS - reflectometry methods for estimation of sea level variations using a single GNSS-receiver, which are based on the multipath propagation effects (interference pattern in SNR of GNSS signals at small elevation angles) caused by the reflection of navigational signals from the sea surface. The measurements were carried out in the coastal zone of Black Sea at the Stationary Oceanographic Platform during one-week campaign in the summer 2017. GPS/GLONASS signals at two working frequencies of both systems were used to study sea level variations which almost doubled the amount of observations compared to GPS-only tide gauge. Moreover all the measurements were conducted with 4-antenna GNSS receiver providing the opportunity for different orientations of antennas including zenith and nadir looking ones as well as two horizontally oriented ones at different azimuths. As the reference we used data from co-located wire wave gauge which showed good correspondence of both datasets. Though tidal effects are not so pronounced for the Black Sea, the described experimental setup allowed to study the effects of sea surface roughness, driven by meteorological conditions (e.g. wind waves), as well as antenna directivity pattern effects on the observed interference patterns of GPS/GLONASS L1/L2 signals (relation of the main spectral peak to the noise power) and the quality of sea level estimations.

Sediment-associated aliphatic and aromatic hydrocarbons in coastal British Columbia, Canada: Concentrations, composition, and associated risks to protected sea otters

International Nuclear Information System (INIS)

Harris, Kate A.; Yunker, Mark B.; Dangerfield, Neil; Ross, Peter S.

2011-01-01

Sediment-associated hydrocarbons can pose a risk to wildlife that rely on benthic marine food webs. We measured hydrocarbons in sediments from the habitat of protected sea otters in coastal British Columbia, Canada. Alkane concentrations were dominated by higher odd-chain n-alkanes at all sites, indicating terrestrial plant inputs. While remote sites were dominated by petrogenic polycyclic aromatic hydrocarbons (PAHs), small harbour sites within sea otter habitat and sites from an urban reference area reflected weathered petroleum and biomass and fossil fuel combustion. The partitioning of hydrocarbons between sediments and adjacent food webs provides an important exposure route for sea otters, as they consume ∼25% of their body weight per day in benthic invertebrates. Thus, exceedences of PAH sediment quality guidelines designed to protect aquatic biota at 20% of the sites in sea otter habitat suggest that sea otters are vulnerable to hydrocarbon contamination even in the absence of catastrophic oil spills. - Highlights: → Sediment hydrocarbon signatures differed between remote and impacted coastal sites. → A natural background comprised terrestrial plant alkanes and petrogenic PAHs. → Impacted sites reflected a history of petrogenic and pyrogenic hydrocarbon inputs. → Hydrocarbons at some sites exceeded guidelines for the protection of aquatic life. → Protected sea otters may thus be at risk as they rely primarily on benthic prey. - Anthropogenically-derived hydrocarbons in coastal sediments in British Columbia may pose a risk to protected sea otters.

Coastal sea-ice processes in Alaska and their relevance for sediment dynamics and coastal retreat (Invited)

Science.gov (United States)

Eicken, H.; Kapsch, M.; Johnson, M. A.; Weyapuk, W. U., Jr.

2009-12-01

Sea ice plays an important, complicated role in Arctic coastal sediment dynamics. It helps protect the shoreline from wave action and constrains coastal permafrost thaw; at the same time, sea ice is a highly effective sediment erosion and transport agent. For the coastline of (sub-)Arctic Alaska we have examined key processes that govern the role of sea ice as a geologic agent. Based on passive microwave satellite data for the time period 1979 to 2008 and augmented by field measurements and observations conducted by local sea-ice experts in coastal communities from 2006 onwards, we determined the onset of coastal ice spring break-up and fall freeze-up. These two events define the start and end of the open-water season during which the coast is rendered most vulnerable to thermal and dynamic processes promoting erosion. Satellite data show significant trends toward later fall freeze-up in many locations and moreover provide a picture of the statistical significance and variability of such trends in great spatio-temporal detail. Coastal ice observations suggest that important sea-ice processes (such as formation of ice berms) that precede freeze-up as detected by passive microwave data need to be taken into consideration in evaluating the vulnerability of the coastline and the specific threat of individual storms. Field observations, satellite data and local knowledge also highlight the substantial change in winter sea-ice regimes over the past two decades, with a much more mobile ice cover enhancing winter sediment transport. Ultimately, the shorter sea-ice season and the greater mobility and the lack of stability of winter coastal sea ice work in concert to increase the vulnerability of the coastline to erosion and flooding. At the same time, these changes provide a mechanism for effective redistribution and cross-shelf transport of sediments that prepares the stage for further erosive action in subsequent seasons.

Hydrothermal influence on nearshore sediments of Kos Island, Aegean Sea

Science.gov (United States)

Megalovasilis, Pavlos; Godelitsas, Athanasios

2015-04-01

The Kos-Nisyros volcanic centre is a long-active, Plio-Pleistocene magmatic system in the subduction zone along the easternmost edge of the active Hellenic volcanic arc in the Aegean Sea. Although today there are signs of relative quiescence in volcanic activity, active onshore fumaroles and shallow-sea hydrothermal vents persist on, amongst others, the island of Kos. The present study explores the large-scale imprint of hydrothermally sourced heavy metals and nutrients on the island's coastal marine environment, based on geochemical data collected in September 2007 from hydrothermal waters and surficial nearshore sediments (Kos is severely influenced by ongoing submarine hydrothermal activity, and confirm that shallow-water sediment Fe, Mn, Zn and Pb levels are substantially higher than those of other islands along the Hellenic volcanic arc, and even exceed those of some deep-water hydrothermal vents in other world regions. Evidently, there may be significant metallic sulphide deposits of hydrothermal origin at depth beneath Kos.

Assessment of the Wave Energy in the Black Sea Based on a 15-Year Hindcast with Data Assimilation

Directory of Open Access Journals (Sweden)

Liliana Rusu

2015-09-01

Full Text Available The principal target of the present work is to assess the wave energy potential in the Black Sea, identifying also some relevant energetic features and possible patterns. A wave prediction system based on the Simulating Waves Nearshore model (SWAN has been implemented and intensively tested in the entire sea basin. Moreover, considering an optimal interpolation technique, an assimilation scheme of the satellite data has been developed, leading to a visible improvement of the wave model predictions in terms of significant wave heights and, consequently, also in terms of wave power. Using this wave prediction system with data assimilation, simulations have been performed for a 15-year period (1999–2013. Considering the results of this 15-year wave hindcast, an analysis of the wave energy conditions in the basin of the Black Sea has been carried out. This provided a more comprehensive picture concerning the wave energy patterns in the coastal environment of the Black Sea focused on the average wave conditions that might be expected in this sea. Following the results presented, it can be concluded that the wave energy extraction in the Black Sea can become an issue of interest, especially from the perspective of the hybrid solutions.

BIO ARGO floats: tools for operational monitoring of the Black Sea

Science.gov (United States)

Palazov, Atanas; Slabakova, Violeta; Peneva, Elisaveta; Stanev, Emil

2014-05-01

The assessment of ecological status in the context of the Water Framework Directive (WFD) and Marine Strategy Framework Directive (MSFD) requires comprehensive knowledge and understanding of the physical and biogeochemical processes that determine the functioning of marine ecosystems. One of the main challenges however is the need of data with frequency relevant to the spatial and temporal scales of the ecological processes. The majority of in situ observations that are commonly used for ecological monitoring of the Black Sea are generally based on near-shore monitoring programs or irregular oceanographic cruises that provide either non-synoptic, coarse resolution realizations of large scale processes or detailed, but time and site specific snapshots of local features. These gaps can be filled by two independent sources: satellite observation and profiling floats. In fact satellite ocean color sensors allows for determination at synoptic scale of water quality parameters through its absorption properties. However the satellite ocean color methods have a number of limitations such as: measurements can only be made during daylight hours; require cloud-free conditions and are sensitive to atmospheric aerosols; provide information only for the upper layer of the ocean (approximately the depth of 10% incident light); algorithms developed for global applications are a source of large uncertainties in the marginal seas and costal areas. These constrains of the optical remote sensing observations can be avoided by using miniature biogeochemical sensors and autonomous platforms that offer remarkable perspectives for observing the "biological" ocean, notably at critical spatiotemporal scales which have been out of reach until recently (Claustre et al., 2010). In the frame of "E-AIMS: Euro-Argo Improvements for the GMES marine Service" 7 EC FP project two Bio Argo floats were deployed in the Black Sea. Beside the traditionally CTD the floats were equipped with biogeochemical

77 FR 60945 - 2012-2013 Accountability Measure and Closure for Commercial Black Sea Bass in the South Atlantic

Science.gov (United States)

2012-10-05

... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 622 [Docket No. 0907271173-0629-03] RIN 0648-XC152 2012-2013 Accountability Measure and Closure for Commercial Black Sea Bass... accountability measure (AM) for the commercial sector of black sea bass in the exclusive economic zone (EEZ) of...

Marine sediments and palaeoclimatic variations since the Late Pleistocene: An overview for the Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Nigam, R.; Hashimi, N.H.

A large number of surfacial and sub-surface sediments from the Arabian Sea have been studied to enhance our understanding of palaeoclimatic variations over the Indian region. Bsically the surficial sediments have been studied for their living...

Long-term viability of carbon sequestration in deep-sea sediments

Science.gov (United States)

Teng, Y.; Zhang, D.

2017-12-01

Sequestration of carbon dioxide in deep-sea sediments has been proposed for the long-term storage of anthropogenic CO2, due to the negative buoyancy effect and hydrate formation under conditions of high pressure and low temperature. However, the multi-physics process of injection and post-injection fate of CO2 and the feasibility of sub-seabed disposal of CO2 under different geological and operational conditions have not been well studied. On the basis of a detailed study of the coupled processes, we investigate whether storing CO2 into deep-sea sediments is viable, efficient, and secure over the long term. Also studied are the evolution of the multiphase and multicomponent flow and the impact of hydrate formation on storage efficiency during the upward migration of the injected CO2. It is shown that low buoyancy and high viscosity slow down the ascending plume and the forming of the hydrate cap effectively reduces the permeability and finally becomes an impermeable seal, thus limiting the movement of CO2 towards the seafloor. Different flow patterns at varied time scales are identified through analyzing the mass distribution of CO2 in different phases over time. Observed is the formation of a fluid inclusion, which mainly consists of liquid CO2 and is encapsulated by an impermeable hydrate film in the diffusion-dominated stage. The trapped liquid CO2 and CO2 hydrate finally dissolve into the pore water through diffusion of the CO2 component. Sensitivity analyses are performed on storage efficiency under variable geological and operational conditions. It is found that under a deep-sea setting, CO2 sequestration in intact marine sediments is generally safe and permanent.

Strontium isotopic study of sediment from the Ross Sea

International Nuclear Information System (INIS)

Kovach, J.; Faure, G.

1977-01-01

A preliminary report summarizing the results of a study of the strontium-87/strontium-86 ratios and of the rubidium and strontium concentrations of the fine-grained (less than 150 microns) noncarbonate fractions of sediment samples from core E32-25 raised from a depth of 327 fathoms in the Ross Sea at 78 0 31.0'S 164 0 24.7'W was presented. The strontium-87/strontium-86 ratios of the samples analyzed range from 0.7119 to 0.7220. Rubidium and strontium concentrations range, respectively, from 126 to 164 parts per million and from 113 to 174 parts per million. The observed strontium-87/strontium-86 ratios and strontium concentrations in sediment samples from core E32-25 fit a hyperbolic curve. These ratios can be used to estimate the concentrations of volcanogenic detritus in the sediment samples. The results of this study provide additional baseline data for anticipated future studies of sediment cores to be recovered from beneath the Ross Ice Shelf by the Ross Ice Shelf Project. 1 figure

Relation between PAH and black carbon contents in size fractions of Norwegian harbor sediments

International Nuclear Information System (INIS)

Oen, Amy M.P.; Cornelissen, Gerard; Breedveld, Gijs D.

2006-01-01

Distributions of total organic carbon (TOC), black carbon (BC), and polycyclic aromatic hydrocarbons (PAH) were investigated in different particle size fractions for four Norwegian harbor sediments. The total PAH (16-EPA) concentrations ranged from 2 to 113 mg/kg dry weight with the greatest fraction of PAH mass in the sand fraction for three of the four sediments. TOC contents ranged from 0.84% to 14.2% and BC contents from 0.085% to 1.7%. This corresponds to organic carbon (OC = TOC - BC) contents in the range of 0.81-14% and BC:TOC ratios of 1.3-18.1%. PAH isomer ratios suggested that the PAH in all four sediments were of pyrogenic origin. Furthermore, stronger correlations between PAH versus BC (r 2 = 0.85) than versus OC (r 2 = 0.15) were found. For all size fractions and bulk sediments, the PAH-to-BC ratios for the total PAHs were on average 6 ± 3 mg PAH/g BC. These results suggest that PAH distributions were dominated by the presence of BC, rather than OC. As sorption to BC is much stronger than sorption to OC, this may result in significantly lower dissolved concentrations of PAH than expected on the basis of organic carbon partitioning alone. - PAH contents correlated better with black carbon than organic carbon for four Norwegian harbor sediments

System of the Wind Wave Operational Forecast by the Black Sea Marine Forecast Center

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Yu.B. Ratner

2017-10-01

Full Text Available System of the wind wave operational forecast in the Black Sea based on the SWAN (Simulating Waves Nearshore numerical spectral model is represented. In the course of the system development the SWAN model was adapted to take into account the features of its operation at the Black Sea Marine Forecast Center. The model input-output is agreed with the applied nomenclature and the data representation formats. The user interface for rapid access to simulation results was developed. The model adapted to wave forecast in the Black Sea in a quasi-operational mode, is validated for 2012–2015. Validation of the calculation results was carried out for all five forecasting terms based on the analysis of two-dimensional graphs of the wave height distribution derived from the data of prognostic calculations and remote measurements obtained with the altimeter installed on the Jason-2 satellite. Calculation of the statistical characteristics of the deviations between the wave height prognostic values and the data of their measurements from the Jason-2 satellite, as well as a regression analysis of the relationship between the forecasted and measured wave heights was additionally carried out. A comparison of the results obtained with the similar results reported in the works of other authors published in 2009–2016 showed their satisfactory compliance with each other. The forecasts carried out by the authors for the Black Sea as well as those obtained for the other World Ocean regions show that the current level of numerical methods for sea wave forecasting is in full compliance with the requirements of specialists engaged in studying and modeling the state of the ocean and the atmosphere, as well as the experts using these results for solving applied problems.

Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

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M.-C. Ciobanu

2012-09-01

Full Text Available An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion. Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG, within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG and Halobacteria within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria within Proteobacteria phylum, and also members of Bacteroidetes phylum. The second most abundant lineages were Actinobacteria and Firmicutes at the Gulf of Lion site and Chloroflexi at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: Alpha-, Gammaproteobacteria, Firmicutes and Actinobacteria. In molecular surveys, the Betaproteobacteria group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea levee. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence

Distribution and Composition of Thiotrophic Mats in the Hypoxic Zone of the Black Sea (150–170 m Water Depth, Crimea Margin)

Science.gov (United States)

Jessen, Gerdhard L.; Lichtschlag, Anna; Struck, Ulrich; Boetius, Antje

2016-01-01

At the Black Sea chemocline, oxygen- and sulfide-rich waters meet and form a niche for thiotrophic pelagic bacteria. Here we investigated an area of the Northwestern Black Sea off Crimea close to the shelf break, where the chemocline reaches the seafloor at around 150–170 m water depth, to assess whether thiotrophic bacteria are favored in this zone. Seafloor video transects were carried out with the submersible JAGO covering 20 km2 on the region between 110 and 200 m depth. Around the chemocline we observed irregular seafloor depressions, covered with whitish mats of large filamentous bacteria. These comprised 25–55% of the seafloor, forming a belt of 3 km width around the chemocline. Cores from the mats obtained with JAGO showed higher accumulations of organic matter under the mats compared to mat-free sediments. The mat-forming bacteria were related to Beggiatoa-like large filamentous sulfur bacteria based on 16S rRNA sequences from the mat, and visual characteristics. The microbial community under the mats was significantly different from the surrounding sediments and enriched with taxa affiliated with polymer degrading, fermenting and sulfate reducing microorganisms. Under the mats, higher organic matter accumulation, as well as higher remineralization and radiotracer-based sulfate reduction rates were measured compared to outside the mat. Mat-covered and mat-free sediments showed similar degradability of the bulk organic matter pool, suggesting that the higher sulfide fluxes and subsequent development of the thiotrophic mats in the patches are consequences of the accumulation of organic matter rather than its qualitative composition. Our observations suggest that the key factors for the distribution of thiotrophic mat-forming communities near to the Crimean shelf break are hypoxic conditions that (i) repress grazers, (ii) enhance the accumulation and degradation of labile organic matter by sulfate-reducers, and (iii) favor thiotrophic filamentous bacteria

MULTILATERAL COOPERATION IN THE BLACK SEA REGION IN THE ENERGY FIELD

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Andrey Vyacheslavovich Ishin

2015-01-01

Full Text Available In the article the state of international cooperation is analysed in the field of energy in Black Sea besseyne. Problems and prospects of development of power communications, their influence, are examined on the level of international stability.

Paleocorrosion studies in deep sea sediments and the geological disposal of nuclear wastes

International Nuclear Information System (INIS)

Fehrenbach, L.; Maurette, M.; Guichard, F.; Havette, A.; Monaco, A.

1984-01-01

Uncertainties still surround assessment of the safety of disposal of nuclear wastes incorporated into 'radwaste' matrices. This is mostly due to the long time required for radioactive decay of 237 Np. The present work explores the usefulness of an experimental approach in 'paleocorrosion', which should help in minimizing such uncertainties. In this approach, polished sections of sediments containing high concentrations of natural analogues of radwaste matrices are subjected to element micromapping. Thus it is possible to characterize the long-term interactions of such analogues in their geological repositories, and to identify which generate reaction aureoles and protective and/or unprotective coatings. These analogues include grains incorporated in deep sea sediments (uraninite and quartz from the Oklo uranium ore deposit; volcanic ash particles; magnetic cosmic spherules). The present results indicate that uraninite should be a much more durable radwaste matrix than any type of glass in deep sea sediments. (orig./TWO)

Use of Cs-137 as tracer in lake sediment investigation

International Nuclear Information System (INIS)

Dinescu, L.; Vasile, E.; Timofte, L.; Cernisov, G.; Dorcioman, R.

1997-01-01

137 Cs vertical profile and total inventories were determined in four lakes located in Danube Delta and surroundings and in channel Dunavat. The radiocaesium total inventory of 1800 Bq/m 2 in Matita and Merhei-Middle Part, very closed to the atmospheric fallout value and a very low sedimentation rate, suggest a relative isolation of these two lakes related to the main Danube branches. The vertical profile obtained in Merhei lake (the Southern part) shows three distinct peaks corresponding to nuclear weapons tests performed in 1954 and 1963 and to Chernobyl event in 1986. Radiocaesium total inventory of 3270 Bq/m 2 was explained by an important 137 Cs contribution from the sediment transported by the channel linking lake Merhei to Dunarea Veche (Chilia branch). For the lakes Leahova and Razim, located in the immediate vicinity of the Black Sea, the total inventories of 600 Bq/m2 suggest an important transfer of sediments from the lakes to Black Sea. 137 Cs vertical profile in Dunavat channel shows two peaks, corresponding to Chernobyl event and nuclear tests. The total inventory of 2600 Bq/m 2 is due to atmospheric fallout and to the sediments transported by the river Danube and then by channel Dunavat. The sedimentation rate of 0.7 cm/year obtained from both peaks, suggests a constant sediment accumulation in the last 33 years. Other environmental tracers were used for recent lake sediment dating. The obtained results (considered as preliminary results) were compared with 137 Cs results. The results obtained from 137 Cs, 210 Pb and 241 Am measurements demonstrated that the environmental tracers are a valuable tool in sediment origin, transport and accumulation investigation. The research is in progress. (authors)

Controls of Multiple Stressors on the Black Sea Fishery

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Temel Oguz

2017-04-01

Full Text Available Black Sea is one of the most severely degraded and exploited large marine ecosystems in the world. For the last 50 years after the depletion of large predatory fish stocks, anchovy (with the partial contribution of sprat has been acting as the main top predator species and experienced a major stock collapse at the end of 1990s. After the collapse, eastern part of the southern Black Sea became the only region sustaining relatively high anchovy catch (400,000 tons whereas the total catch within the rest of the sea was reduced to nearly its one-third. The lack of recovery of different fish stocks under a slow ecosystem rehabilitation may be attributed, on the one hand, to inappropriate management measures and the lack of harmonized fishery policy among the riparian countries. On the other hand, impacts of multiple stressors (eutrophication, alien species invasions, natural climatic variations on the food web may contribute to resilience of the system toward its recovery. The overfishing/recovery problem therefore cannot be isolated from rehabilitation efforts devoted to the long-term chronic degradation of the food web structure, and alternative fishery-related management measures must be adopted as a part of a comprehensive ecosystem-based management strategy. The present study provides a data-driven ecosystem assessment, underlines the key environmental issues and threats, and points to the critical importance of holistic approach to resolve the fishery-ecosystem interactions. It also stresses the transboundary nature of the problem.

Biogeographical distribution and diversity of bacterial communities in surface sediments of the South China Sea.

Science.gov (United States)

Li, Tao; Wang, Peng

2013-05-01

This paper aims at an investigation of the features of bacterial communities in surface sediments of the South China Sea (SCS). In particular, biogeographical distribution patterns and the phylogenetic diversity of bacteria found in sediments collected from a coral reef platform, a continental slope, and a deep-sea basin were determined. Bacterial diversity was measured by an observation of 16S rRNA genes, and 18 phylogenetic groups were identified in the bacterial clone library. Planctomycetes, Deltaproteobacteria, candidate division OP11, and Alphaproteobacteria made up the majority of the bacteria in the samples, with their mean bacterial clones being 16%, 15%, 12%, and 9%, respectively. By comparison, the bacterial communities found in the SCS surface sediments were significantly different from other previously observed deep-sea bacterial communities. This research also emphasizes the fact that geographical factors have an impact on the biogeographical distribution patterns of bacterial communities. For instance, canonical correspondence analyses illustrated that the percentage of sand weight and water depth are important factors affecting the bacterial community composition. Therefore, this study highlights the importance of adequately determining the relationship between geographical factors and the distribution of bacteria in the world's seas and oceans.

Indicator polychlorinated biphenyl residues in muscle tissue of fish from Black Sea coast of Bulgaria

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S. Georgieva

2016-06-01

Full Text Available Abstract. Polychlorinated biphenyls (PCBs are characterized by high lipophilicity and persistence in the environment and will therefore bioaccumulate and biomagnify in the food chain. PCBs were determined in muscle tissue of four fish species: goby (Neogobius melanostomus, horse mackerel (Trachurus Mediterraneus ponticus, shad (Alosa pontica pontica and turbot (Psetta maxima maeotica. Samples were collected from Bulgarian Black Sea coast during 2007 – 2011. The PCBs were analyzed in order to examine the time trends of PCB concentrations in fish from Black Sea. The six individual PCBs congeners were determined by capillary gas chromatography system with mass spectrometry detection. PCBs were found in all fish species at concentrations ranging between 2.32 ng/g ww (wet weight and 32.87 ng/g ww in goby and shad, respectively. PCB profiles have been found to be similar in all the fish species tested. The most abundant PCB congeners in fish species were hexa- and heptachlorinated PCBs 138, 153 and 180. PCB 153 was the dominant congener in all fish studied and were found in the range from 0.95 ng/g ww (horse mackerel 2011 to 11.67 ng/g ww (shad 2010. The sum of six indicator PCBs in all fish species did not exceed the European maximum limit of 75 ng/g ww. The levels of PCBs in fish from Bulgarian Black Sea coast were found lower than in fish species from other seas – the Aegean Sea and the Mediterranean Sea.

STUDIES ON THE NUTRIENT CONTENT OF SPECIES Mytilus galloprovincialis OF THE BLACK SEA

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Rodica Sirbu

2011-09-01

Full Text Available It is well known that, among the marine organisms, mollusks are highly appreciated in many European, Asian and North American countries. In the Romanian area of the Black Sea, mussel Mytilus galloprovincialis can be found in deep areas which form a belt around the sea on the continental platform. There are significant variations of the main environmental factors which directly influence the physiological behavior of the organisms and the accumulation of the biochemical components with nutritional value. This paper correlates the study of the dynamics of the main biochemical compounds with the environmental factors and the annual ontogenetic phases of the organisms. There are also presented comparative studies concerning the rock mollusks and mollusks of deep from the Black Sea. It was found variations in quantitative results for biochemical composition. Cases are due to seasonal variations of physical-chemical conditions of seawater.

Accumulation of organic carbon in northwestern Arabian sea sediments

International Nuclear Information System (INIS)

Khan, A.A.

1999-01-01

In this study accumulation of organic carbon in marine sediments of northwestern Arabian sea has been discussed. This paper presents the geochemical analysis of Organic carbon content and accumulation, delta 13 stable carbon isotope and Ba/Al. The primary objective was to investigate the high resolution information about the variations in paleoproductivity and source of organic matter in sediments below an upwelling area. Undisturbed sediments (Piston core NIOP-486) of late Pleistocene time were collected during Netherlands Indian Ocean Program (NIOP-1992-93). The core NIOP-486 was raised from a depth of 2077 meters near the Owen Ridge. This core records deposition history of last 200,000 years and includes 4 warm and 3 cold periods. The distribution of organic carbon content in studied core shows a pronounced cyclicity during glacial and interglacial stages. Organic carbon accumulation trends show that high sedimentation rates in glacial stages results in rapid burial and hence increase organic carbon accumulation. Paleoproductivity indicator Ba/Al has been used to compare with the organic carbon content and is correlated with the warm and cold periods variations in monsoons upwelling intensity. Generally, low paleoproductivity is found in glacial stages. The organic carbon content and accumulation, in sediments however seems to differ from the paleoproductivity trends shown by Ba/Al in glacial sediments of stage 6. Delta 13 C.org isotope results of the core NIOP-486 confirm that organic matter in sediments is predominantly marine (-20 to -23% ). (author)

Deglacial remobilization of permafrost carbon to sediments along the East Siberian Arctic Seas

Science.gov (United States)

Martens, J.; Wild, B.; Bröder, L.; Andersson, A.; Pearce, C.; O'Regan, M.; Jakobsson, M.; Tesi, T.; Muschitiello, F.; Sköld, M.; Semiletov, I. P.; Dudarev, O.; Gustafsson, O.

2017-12-01

Current climate change is expected to thaw large quantities of permafrost carbon (PF-C) and expose it to degradation which emits greenhouse gases (i.e. CO2 and CH4). Warming causes a gradual deepening of the seasonally thawed active layer surface of permafrost soils, but also the abrupt collapse of deeper Ice Complex Deposits (ICD), especially along Siberian coastlines. It was recently hypothesized that past warming already induced large-scale permafrost degradation after the last glacial, which ultimately amplified climate forcing. We here assess the mobilization of PF-C to East Siberian Arctic Sea sediments during these warming periods. We perform source apportionment using bulk carbon isotopes (ΔΔ14C, δ13C) together with terrestrial biomarkers (CuO-derived lignin phenols) as indicators for PF-C transfer. We apply these techniques to sediment cores (SWERUS-L2) from the Chukchi Sea (4-PC1) and the southern Lomonosov Ridge (31-PC1). We found that PF-C fluxes during the Bølling-Allerød warming (14.7 to 12.7 cal ka BP), the Younger Dryas cooling (12.7 to 11.7 cal ka BP) and the early Holocene warming (until 11 cal ka BP) were overall higher than mid and late Holocene fluxes. In the Chukchi Sea, PF-C burial was 2x higher during the deglaciation (7.2 g m-2 a-1) than in the mid and late Holocene (3.6 g m-2 a-1), and ICD were the dominant source of PF-C (79.1%). Smaller fractions originated from the active layer (9.1%) and marine sources (11.7%). We conclude that thermo-erosion of ICD released large amounts of PF-C to the Chukchi Sea, likely driven by climate warming and the deglacial sea level rise. This contrasts to earlier analyses of Laptev Sea sediments where active layer material from river transport dominated the carbon flux. Preliminary data on lignin phenol concentrations of Lomonosov Ridge sediments suggest that the postglacial remobilization of PF-C was one order of magnitude higher (10x) than during both the preceding glacial and the subsequent Holocene

Modification of analytical method for measurement of 239Pu, 240Pu and 241Am in sediment and sea water

International Nuclear Information System (INIS)

Syarbaini; Tarigan, C.; Rustam, M.F.

1997-01-01

Modification of analytical method for measurement of 239 Pu, 240 Pu and 241 Am in sediment and sea water have been conducted. This study is to develop a method for separation of 239 Pu, 240 Pu and 241 Am from 100-300 g of sediment and 100-200 l of sea water samples. Most of the methods described in the literature are to separation of '2 39 Pu, '2 40 Pu and 241 Am from 20-50 g of sediment and 30-100 l of sea water samples. By this method, 239,240 Pu and 241 Am were concentrated using the coprecipitation of CaC 2 O 4 and Fe (OH) 3 . Plutonium-242 and Curium-244 were used as tracer to determine chemical recovery. The result of analysis of some sediment samples showed that the chemical recoveries were respectively obtained in the range of 59.7 to 72.6% with average of 66.2 % for 242 Pu and 72.0 % to 85.5 % with average 78.8 % for 244 Cm. Analysis of some sea water samples were obtained in the range of 67 % to 78 % with average 73.9 % for 242 Pu and 74.0 % to 90.0 % with average 84.2 % for '2 42 Cm. This method was tested by the IAEA marine sediment, the result was excellent agreement with the IAEA certified sediment. It could be suggested that the developed analytical method is suitable to analyze the low level 239 Pu, 240 Pu and 241 Am in sediment and sea water samples (author)

Influences of sediment redistribution on sea-level changes along the U.S. Atlantic margin since the mid-Pliocene

Science.gov (United States)

Li, Q.; Ferrier, K.; Austermann, J.; Mitrovica, J. X.

2017-12-01

The Orangeburg Scarp is a paleo-shoreline formed along the southeastern U.S. Atlantic coast during the mid-Pliocene warm period (MPWP; 3.3 - 2.9 Ma). The MPWP is a time of interest because it is often cited as an analog for modern climate and thus an important target for understanding sea-level responses to climate change. The present Orangeburg Scarp exhibits 40-meter variations in elevation along its length, implying that it has been warped since its formation, which complicates efforts to infer global ice volume at the MPWP. Previous studies have shown that the effects of glacial isostatic adjustment (GIA) and dynamic topography (DT) on sea level can explain a significant fraction of the observed variability in elevation along the Orangeburg Scarp. Here we build on these studies by using a gravitationally self-consistent ice age sea-level model to compute the effects of sediment loading and unloading on paleo-shoreline elevation since the mid-Pliocene. To constrain the sediment loading history in this region, we present a new compilation of erosion and deposition rates along the U.S. Atlantic margin, from which we generate a range of sediment redistribution scenarios since the MPWP. We simultaneously drive the sea-level model with these sediment redistribution histories and existing ice and dynamic topography histories. Our results show that sediment loading and unloading is capable of warping the elevation of this paleo-shoreline by 20 meters since its formation, similar in magnitude to the contributions from GIA and DT over the same time period. These results demonstrate that sediment redistribution can induce significant perturbations in sea-level markers from the MPWP, and thus accounting for its influence will improve reconstructions of sea level and global ice volume during the MPWP and perhaps other periods of relative ice age warmth.

Chemical and physical properties of the surface sea sediments at the Olkiluoto offshore, South-Western Finland

International Nuclear Information System (INIS)

Lahdenperae, A.-M.; Keskinen, A.

2011-11-01

Due to land uplift, the present sea sediments near Olkiluoto will be future land areas, and thus important for the transport of possible releases from nuclear waste repositories at the site. Coastal areas are the transition zones between land and sea, and also potential sites for deep groundwater discharge. The geochemical properties of the surface sediments at the Olkiluoto sea area are summarised in this report. Thirteen sediment samples were cored during the R/V Geomari cruise in autumn 2008. In addition, surface sediment samples from six transects, altogether 57 cores, were taken near the Olkiluoto shoreline by diving in the summer of 2008. The analysis procedure included pH, moisture, dry matter, ash and LOI contents, grain size distribution, carbon and nitrogen analyses and the total concentrations of thirtythree elements. The lateral and vertical distribution of element concentrations, especially heavy metals, is caused by variations in transport and sedimentation patterns of particulate matter, in the occurrence of migration processes and bonding types. The distribution pattern in most of the elements is strongly linked to that of organic matter, carbon and fine-grained material contents. The sediments are strongly enriched by some of the studied elements possibly due to anthropogenic load, while others are only moderately or slightly present. However, the source of different natural and anthropogenic loads is not easy to point out. (orig.)

Tritium activity concentration along the Western shore of the Black Sea

International Nuclear Information System (INIS)

Carmen Varlam; Faurescu, I.; Irina Vagner; Denisa Faurescu; Patrascu, V.; Margineanu, R.M.; Duliu, O.G.

2013-01-01

The Black Sea tritium level was investigated in 33 places southward the Danube Delta covering about 360 km of the Black Sea Western Shore. Both surface (10 cm depth) and bottom (up to 20 m depth) water samples were collected. In the close vicinity of Danube Delta, the tritium activity concentration in the surface water was around 28 TU, which is almost the same as that of the Danube River waters, but it decreased to about 5 TU in the bottom water. This discrepancy slowly diminished wherein at about 120 km southward, the tritium content in both surface and bottom water reached almost the same constant value of 6.5 ± 2.3 TU. This value, about two and a half times smaller than that reported 17 years ago, remained almost unchanged for the last 240 km of shore up to the Turkish border. (author)

Organic matter content and particle size modifications in mangrove sediments as responses to sea level rise.

Science.gov (United States)

Sanders, Christian J; Smoak, Joseph M; Waters, Mathew N; Sanders, Luciana M; Brandini, Nilva; Patchineelam, Sambasiva R

2012-06-01

Mangroves sediments contain large reservoirs of organic material (OM) as mangrove ecosystems produce large quantities and rapidly burial OM. Sediment accumulation rates of approximately 2.0 mm year(-1), based on (210)Pb(ex) dating, were estimated at the margin of two well-developed mangrove forest in southern Brazil. Regional data point to a relative sea level (RSL) rise of up to ∼4.0 mm year(-1). This RSL rise in turn, may directly influence the origin and quantity of organic matter (OM) deposited along mangrove sediments. Lithostratigraphic changes show that sand deposition is replacing the mud (<63 μm) fraction and OM content is decreasing in successively younger sediments. Sediment accumulation in coastal areas that are not keeping pace with sea level rise is potentially conducive to the observed shifts in particle size and OM content. Copyright © 2012 Elsevier Ltd. All rights reserved.

Spawning of bluefin tuna in the black sea: historical evidence, environmental constraints and population plasticity

DEFF Research Database (Denmark)

Mackenzie, Brian R; Mariani, Patrizio

2012-01-01

The lucrative and highly migratory Atlantic bluefin tuna, Thunnus thynnus (Linnaeus 1758; Scombridae), used to be distributed widely throughout the north Atlantic Ocean, Mediterranean Sea and Black Sea. Its migrations have supported sustainable fisheries and impacted local cultures since antiquity...

Small fractures in deep sea sediments: indicators of pore fluid migration along compaction faults

International Nuclear Information System (INIS)

Buckley, D.E.

1989-01-01

A long piston core taken from the Southern Nares Abyssal Plain, intersected four fractures in plastic sediments between 17 and 25 m below the sea floor. Faults have been identified from seismic reflection surveys of sediments in this area. The sampled fractures all occurred in oxidized brown clays. Each fracture consisted of a simple plane having apparent dips ranging from 52-63 0 . One fracture had a well developed pale brown alteration halo extending out to 1.5 cm along this plane. Two fractures had no apparent alteration halo, but one fracture appeared to have fine-scale anastomosing features surrounding the main slip plane. Selective chemical tests for labile metal content in sediments surrounding the fractures revealed that about 70% of the reducible manganese, and 40% of the reducible iron had been leached from the sediments in the alteration halo surrounding the fracture plane. These results suggest that reducing pore fluids had migrated along the fracture plane to cause the observed effects. Implications of this study are that compaction faults may act as episodic conduits for vertical advection of pore water during dewatering of unconsolidated sediments. This may be a significant factor to be considered in assessing the effectiveness of deep sea sediment barriers for radioactive waste disposal. (author)

Temporal-spatial trends in heavy metal contents in sediment-derived soils along the Sea Scheldt river (Belgium)

International Nuclear Information System (INIS)

Vandecasteele, B.; Vos, B. de; Tack, F.M.G.

2003-01-01

The alluvial plain upstream in the Sea Scheldt was more affected by upland disposal of polluted sediments. - The aim of this study was to survey the alluvial plains of the Sea Scheldt river in Belgium for the presence of old sediment-derived soils, and to appraise the heavy metal contamination at these sites. Historically, sediments of periodical dredging operations have been disposed in the alluvial plain without concern for the potential presence of contaminants. Up to 96% of the areas that were affected by sediment disposal (ca. 120 ha) was found to be polluted by at least one of the metals Cd, Cr, Zn or Pb. Concentrations of Cd, Cr and Zn were, in 10% of the cases, higher than 14, 1400 and 2200 mg/kg DM, respectively. Based on the Flemish decree on soil sanitation, Cu and Ni concentrations were of less environmental concern on any site. The pollution in the Sea Scheldt alluvial plain nevertheless is lower than for the Upper Scheldt alluvial plain. The sediment-derived soils in the most upstream part near Ghent were used for disposal of sediments from dredging operations elsewhere. Metal concentrations were explored and both spatial and temporal trend were analysed. The pollution levels encountered warrant caution as most of the soils affected by historical dredged sediment disposal are currently in use for pasture

Gas nad mud volcanism formation as a result of geodynamic development of the Black sea region

International Nuclear Information System (INIS)

Dmitrievsky, A.N.; Karakin, A.V.; Kazmin, V.G.

2002-01-01

Full text : Fluidodynamic model of moving of gas-mud mixture accompanied by eruptions of mud volcanoes and gas bursts is firstly demonstrated by the example of the Black sea basin. The entire spectrum of gas bursts can be divided into gas and mud-fluid volcanoes. Emanation of hydrocarbon gases during the eruptions accompanied by powerful exploison, bursts of gas, water and fragments of rocks as well as by issue of breccia are typical for the first type of volcanoes. It was suggested that the eastern part of the Black sea forms block or subplate moving to the northeast. This conclusion is important for estimation of seismic and connected geological hazard in the studied region. It was established that deformations and seismicity were mainly confined to the edges of the East Black sea subplate while in its inner part the level of seismic activity is considerably lower.

The renewable energy and economic growth nexus in Black Sea and Balkan countries

International Nuclear Information System (INIS)

Koçak, Emrah; Şarkgüneşi, Aykut

2017-01-01

The aim of this study is to explore the relationship between renewable energy consumption and economic growth within the framework of traditional production function for the period of 1990–2012 in 9 Black Sea and Balkan countries. For this purpose, we use panel cointegration, co-integration estimate methods and heterogeneous panel causality estimation techniques. The study has concluded that there is a long term balance relationship between renewable energy consumption and economic growth and renewable energy consumption has a positive impact on economic growth. Heterogeneous panel causality analysis results support growth hypothesis in Bulgaria, Greece, Macedonia, Russia and Ukraine; feedback hypothesis in Albania, Georgia and Romania; neutrality hypothesis in Turkey and according to the panel data set including all nine countries the results support feedback hypothesis. With the findings, it was concluded that there is a significant impact of renewable energy consumption on economic growth in Balkan and Black Sea Countries. - Highlights: • Explores the impact of renewable energy on economic growth in Black Sea and Balkan countries. • Employs panel cointegration and heterogeneous causality analyses. • Finds significant effect of renewable energy consumption on economic growth. • Finds bidirectional causality between renewable energy consumption and economic growth for the whole panel.

Technique for Simulation of Black Sea Circulation with Increased Resolution in the Area of the IO RAS Polygon

Science.gov (United States)

Gusev, A. V.; Zalesny, V. B.; Fomin, V. V.

2017-11-01

A numerical technique is presented for simulating the hydrophysical fields of the Black Sea on a variable-step grid with refinement in the area of IO RAS polygon. Model primitive equations are written in spherical coordinates with an arbitrary arrangement of poles. In order to increase the horizontal resolution of the coastal zone in the area of the IO RAS polygon in the northeastern part of the sea near Gelendzhik, one of the poles is placed at a land point (38.35° E, 44.75° N). The model horizontal resolution varies from 150 m in the area of the IO RAS polygon to 4.6 km in the southwestern part of the Black Sea. The numerical technique makes it possible to simulate a large-scale structure of Black Sea circulation as well as the meso- and submesoscale dynamics of the coastal zone. In order to compute the atmospheric forcing, the results of the regional climate model WRF with a resolution of about 10 km in space and 1 h in time are used. In order to demonstrate the technique, Black Sea hydrophysical fields for 2011-2012 and a passive tracer transport representing self-cleaning of Gelendzhik Bay in July 2012 are simulated.

Quaternary sediments in Rybalsryi quarry of Dnipropetrovsk

Directory of Open Access Journals (Sweden)

Manyuk V.V.

2014-12-01

Full Text Available The results of a study of the typical section of Quaternary sediments in the Rybalske quarry and first time been reported to shift to the South boundary of the spread of the Dneprovian ice cover. Long-term observation of the geological structure subaerial and subaqueous deposits in Quaternary escarpment quarry clearly demonstrates the exceptional value, integrity, and at the same time, a certain exclusivity individual elements Quaternary section. Middle-upper Pleistocene section of substantially exceeds disclosed in Sazhovka draw, where the stratotype Kodatskiy fossil soil and elevated section of Quaternary sediments. If old Kodak can see only fragments section, an opened side by deep ravines and conditions of use cleared, the Rybalske quarry ledge submitted in one complete section alternation fossil soil horizons and loess - loess from the Dnieper to the modern black soil, and another ledge next to, well the rest of the section is exposed (from Tilihulske to Shyrokynske klimatolite. Established that among the many famous sections subaerial deposits located in the Middle Dnieper in the north-eastern part of the Dnieper-Donets basin, in the Black Sea and the Crimea and studied by the author in different years, and described loess and soil horizons (from the Black Sea to the Dnieper differ markedly lack of connectivity, flowability and friability. It is logical to assume that lithofacies conditions of the thicker subaerial deposits in the wellhead part Samara, where the Rybalske quarry markedly different from existing in these areas. Despite the obvious influence of the Dnieper glacier, direct signs which surround Dnipropetrovs’k north must be other reasons not yet explored. It is worth noting another important feature of the section of Quaternary sediments in fishing career. The above section is characteristic of the north-eastern part of the quarry, while the north, at higher marks of the watershed in the lower parts of thicker Quaternary

Microbial diversity in cold seep sediments from the northern South China Sea

Directory of Open Access Journals (Sweden)

Yong Zhang

2012-05-01

Full Text Available South China Sea (SCS is the largest Western Pacific marginal sea. However, microbial studies have never been performed in the cold seep sediments in the SCS. In 2004, “SONNE” 177 cruise found two cold seep areas with different water depth in the northern SCS. Haiyang 4 area, where the water depth is around 3000 m, has already been confirmed for active seeping on the seafloor, such as microbial mats, authigenic carbonate crusts and bivalves. We investigated microbial abundance and diversity in a 5.55-m sediment core collected from this cold seep area. An integrated approach was employed including geochemistry and 16S rRNA gene phylogenetic analyses. Here, we show that microbial abundance and diversity along with geochemistry profiles of the sediment core revealed a coupled reaction between sulphate reduction and methane oxidation. Acridine orange direct count results showed that microbial abundance ranges from 105 to 106 cells/g sediment (wet weight. The depth-related variation of the abundance showed the same trend as the methane concentration profile. Phylogenetic analysis indicated the presence of sulphate-reducing bacteria and anaerobic methane-oxidizing archaea. The diversity was much higher at the surface, but decreased sharply with depth in response to changes in the geochemical conditions of the sediments, such as methane, sulphate concentration and total organic carbon. Marine Benthic Group B, Chloroflexi and JS1 were predominant phylotypes of the archaeal and bacterial libraries, respectively.

Phosphorus binding by poorly crystalline iron oxides in North Sea sediments

NARCIS (Netherlands)

Slomp, C.P.; Gaast, S. J. van der; Raaphorst, W. van

1996-01-01

Differential X-ray powder diffraction (DXRD) and extraction procedures were used to characterize the iron oxides present in four sediments from contrasting environments in the North Sea. Stations were located in depositional areas on the southern shelf (German Bight) and on the north-eastern