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Sample records for arctic marine sediments

  1. Large ancient organic matter contributions to Arctic marine sediments (Svalbard)

    NARCIS (Netherlands)

    Kim, J.-H.; Peterse, F.; Willmott, V.; Klitgaard Kristensen, D.; Baas, M.; Schouten, S.; Sinninghe Damsté, J.S.

    2011-01-01

    Soils, fine-grained ice-rafted detritus (IRD), coals, and marine surface sediments in the Arctic realm (Svalbard) were collected in 2007 and 2008 to characterize organic matter (OM) sources in Arctic marine sediments. Bulk geochemical (C : N ratio and stable carbon isotopic composition) parameters s

  2. Large ancient organic matter contributions to Arctic marine sediments (Svalbard)

    NARCIS (Netherlands)

    Kim, J.-H.; Peterse, F.; Willmott, V.; Klitgaard Kristensen, D.; Baas, M.; Schouten, S.; Sinninghe Damsté, J.S.

    2011-01-01

    Soils, fine-grained ice-rafted detritus (IRD), coals, and marine surface sediments in the Arctic realm (Svalbard)were collected in 2007 and 2008 to characterize organic matter (OM) sources in Arctic marine sediments. Bulkgeochemical (C : N ratio and stable carbon isotopic composition) parameters sug

  3. Diversity and novelty of actinobacteria in Arctic marine sediments.

    Science.gov (United States)

    Zhang, Gaiyun; Cao, Tingfeng; Ying, Jianxi; Yang, Yanliu; Ma, Lingqi

    2014-04-01

    The actinobacterial diversity of Arctic marine sediments was investigated using culture-dependent and culture-independent approaches. A total of 152 strains were isolated from seven different media; 18 isolates were selected for phylogenetic analysis on the basis of their 16S rRNA gene sequences. Results showed that the 18 isolates belonged to a potential novel genus and 10 known genera including Actinotalea, Arthrobacter, Brachybacterium, Brevibacterium, Kocuria, Kytococcus, Microbacterium, Micrococcus, Mycobacterium, and Pseudonocardia. Subsequently, 172 rDNA clones were selected by restriction fragment length polymorphism analysis from 692 positive clones within four actinobacteria-specific 16S rDNA libraries of Arctic marine sediments, and then these 172 clones were sequenced. In total, 67 phylotypes were clustered in 11 known genera of actinobacteria including Agrococcus, Cellulomonas, Demequina, Iamia, Ilumatobacter, Janibacter, Kocuria, Microbacterium, Phycicoccus, Propionibacterium, and Pseudonocardia, along with other, unidentified actinobacterial clones. Based on the detection of a substantial number of uncultured phylotypes showing low BLAST identities (<95 %), this study confirms that Arctic marine environments harbour highly diverse actinobacterial communities, many of which appear to be novel, uncultured species. PMID:24519808

  4. Thermophilic anaerobes in arctic marine sediments induced to mineralize complex organic matter at high temperature

    DEFF Research Database (Denmark)

    Hubert, Casey; Arnosti, Carol; Brüchert, Volker;

    2010-01-01

    Marine sediments harbour diverse populations of dormant thermophilic bacterial spores that become active in sediment incubation experiments at much higher than in situ temperature. This response was investigated in the presence of natural complex organic matter in sediments of two Arctic fjords, ...

  5. Organic carbon degradation in arctic marine sediments, Svalbard: A comparison of initial and terminal steps

    DEFF Research Database (Denmark)

    Arnosti, C.; Jørgensen, BB

    2006-01-01

    carbohydrate concentrations were comparable to those measured in more temperate sediments, and likely comprise a considerable fraction of porewater dissolved organic carbon. A comparison of dissolved carbohydrate inventories with hydrolysis and sulfate reduction rates suggests that the turnover of carbon......Degradation of marine organic matter under anoxic conditions involves microbial communities working in concert to remineralize complex substrates to CO2. In order to investigate the coupling between the initial and terminal steps of this sequence in permanently cold sediments, rates of...... extracellular enzymatic hydrolysis and sulfate reduction were measured in parallel cores collected from 5 fjords on the west and northwest coast of Svalbard, in the high Arctic. Inventories of total dissolved carbohydrates were also measured in order to evaluate their potential role in carbon turnover...

  6. Community structure, cellular rRNA content, and activity of sulfate-reducing bacteria in marine Arctic sediments

    DEFF Research Database (Denmark)

    Ravenschlag, K.; Sahm, K.; Knoblauch, C.;

    2000-01-01

    The community structure of sulfate-reducing bacteria (SRB) of a marine Arctic sediment (Smeerenburg-fjorden, Svalbard) a-as characterized by both fluorescence in situ hybridization (FISH) and rRNA slot blot hybridization by using group- and genus-specific 16S rRNA-targeted oligonucleotide probes...

  7. Isolation and phylogenetic assignation of actinomycetes in the marine sediments from the Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    YU Yong; LI Huirong; ZENG Yinxin; CHEN Bo

    2005-01-01

    Actinomycetes in five marine sediments collected from the Arctic Ocean at depths of 43 to 3 050 m were cultivated using a variety of media. A total of 61 actinomycete colonies with substrate mycelia only were observed, and no colonies with aerial mycelia were observed under aerobic conditions at 15 ℃. From these colonies, 28 were selected to represent different morphological types.Denaturing gradient gel electrophoresis (DGGE) was used to check the purity of isolates and select representatives for subsequent sequencing. Phylogentic analyses based on nearly full-length 16S ribosomal RNA gene (rDNA) sequences indicated that the actinomycetes isolated were accommodated within genus Rhodococcus of family Nocardiaceae, genus Dietzia of family Dietziaceae,genera Janibacter and Terrabacter of family Instrasporangiaceae and genera Kocuria and Arthrobacter of family Micrococcaceae. One of the strains (P27-24) from the deep-sea sediment at depth of 3 050 m was found to be identical in 16S rDNA sequence(1474/1474)with the radiation-resistant Kocuria rosea ATCC 187T isolated from air. More than halfofthe isolates showed the similarities ranging from 99.5% to 99.9% in 16S rDNA sequence to dibenzofran-degrading, butyl 2-ethylhexanoate-hydrolysising and nitrile-metabolizing actinomycetes. All the strains isolated were psychrotolerant bacteria and grew better on the media prepared with natural seawater than on the media prepared with deionized water. Three of them (Dietzia sp. P27-10, Rhodococcus sp. S11-3 and Rhodococcus sp.P11-5)had an obligate growth requirement for salt, confirming that these strains are indigenous marine actinomycetes.

  8. Distribution of branched GDGTs in surface sediments from the Colville River, Alaska: Implications for the MBT'/CBT paleothermometer in Arctic marine sediments

    Science.gov (United States)

    Hanna, Andrea J. M.; Shanahan, Timothy M.; Allison, Mead A.

    2016-07-01

    Significant climate fluctuations in the Arctic over the recent past, and additional predicted future temperature changes, highlight the need for high-resolution Arctic paleoclimate records. Arctic coastal environments supplied with terrigenous sediment from Arctic rivers have the potential to provide annual to subdecadal resolution records of climate variability over the last few millennia. A potential tool for paleotemperature reconstructions in these marine sediments is the revised methylation index of branched tetraethers (MBT')/cyclization ratio of branched tetraethers (CBT) proxy based on branched glycerol dialkyl glycerol tetraethers (brGDGTs). In this study, we examine the source of brGDGTs in the Colville River, Alaska, and the adjacent Simpson Lagoon and reconstruct temperatures from Simpson Lagoon sediments to evaluate the applicability of this proxy in Arctic estuarine environments. The Colville catchment soils, fluvial sediments, and estuarine sediments contain statistically similar brGDGT distributions, indicating that the brGDGTs throughout the system are soil derived with little alteration from in situ brGDGT production in the river or coastal waters. Temperatures reconstructed from the MBT'/CBT indices for surface samples show good agreement with regional summer (June through September) temperatures, suggesting a seasonal bias in Arctic temperature reconstructions from the Colville system. In addition, we reconstruct paleotemperatures from an estuarine sediment core that spans the last 75 years, revealing an overall warming trend in the twentieth century that is consistent with trends observed in regional instrumental records. These results support the application of this brGDGT-based paleotemperature proxy for subdecadal-scale summer temperature reconstructions in Arctic estuaries containing organic material derived from sediment-laden, episodic rivers.

  9. Volatile fatty acids as substrates for iron and sulfate reduction in Arctic marine sediments, Svalbard

    Science.gov (United States)

    Finke, N.; Vandieken, V.; Jorgensen, B. B.

    2006-12-01

    Anaerobic degradation of complex organic material in aquatic systems is a multi-step process. The metabolic products of fermentative bacteria serve as electron donors for the terminal oxidizing bacteria. In marine sediments, iron reduction and sulfate reduction are generally the most important terminal oxidation processes in the upper anoxic zone [1]. Microorganisms that reduce iron and sulfate may use a broad range of electron donors, yet the list of potential substrates provides little information about the substrates used in situ by these organisms. Investigations on the electron donors for sulfate reducers in marine sediments have shown that volatile fatty acids (VFA), and in particular acetate, together with hydrogen are the major substrates (e.g. [2-4]). Similar investigations for iron reduction or simultaneous iron and sulfate reduction are lacking for marine sediments. Furthermore, most of these studies were made in temperate sediments and little is known about the substrates for sulfate reducers in permanently cold sediments, which account for >90% of the ocean floor [5]. We investigated the relative contributions of iron reduction and sulfate reduction to the terminal oxidation of organic carbon and the importance of acetate, lactate, propionate, and isobutyrate as electron donors for iron and sulfate reduction in permanently cold, Arctic sediments from Svalbard. In the surface layer (0-2 cm) sulfate reduction accounted for 2/3 of the organic carbon oxidation (determined as DIC production), the remaining 1/3 were attributed to iron reduction. In the 5-9 cm layer sulfate reduction was the sole important terminal oxidation step. The contribution of acetate to terminal oxidation was determined by radiotracer incubation as well as from the accumulation after the inhibition of sulfate reduction by selenate. The rates determined with the two methods varied by less than 20%. Acetate turnover, determined with the tracer incubations, accounted for 10 and 40% of

  10. Community size and metabolic rates of psychrophilic sulfate-reducing bacteria in Arctic marine sediments

    DEFF Research Database (Denmark)

    Knoblauch, C.; Jørgensen, BB; Harder, J.

    1999-01-01

    of 19 isolated psychrophiles were compared to corresponding rates of 9 marine, mesophilic sulfate-reducing bacteria. The results indicate that, as a physiological adaptation to the permanently cold Arctic environment, psychrophilic sulfate reducers have considerably higher specific metabolic rates than...

  11. Phylogenetic Diversity and Biological Activity of Actinobacteria Isolated from the Chukchi Shelf Marine Sediments in the Arctic Ocean

    Directory of Open Access Journals (Sweden)

    Meng Yuan

    2014-03-01

    Full Text Available Marine environments are a rich source of Actinobacteria and have the potential to produce a wide variety of biologically active secondary metabolites. In this study, we used four selective isolation media to culture Actinobacteria from the sediments collected from the Chukchi Shelf in the Arctic Ocean. A total of 73 actinobacterial strains were isolated. Based on repetitive DNA fingerprinting analysis, we selected 30 representatives for partial characterization according to their phylogenetic diversity, antimicrobial activities and secondary-metabolite biosynthesis genes. Results from the 16S rRNA gene sequence analysis indicated that the 30 strains could be sorted into 18 phylotypes belonging to 14 different genera: Agrococcus, Arsenicicoccus, Arthrobacter, Brevibacterium, Citricoccus, Janibacter, Kocuria, Microbacterium, Microlunatus, Nocardioides, Nocardiopsis, Saccharopolyspora, Salinibacterium and Streptomyces. To our knowledge, this paper is the first report on the isolation of Microlunatus genus members from marine habitats. Of the 30 isolates, 11 strains exhibited antibacterial and/or antifungal activity, seven of which have activities against Bacillus subtilis and Candida albicans. All 30 strains have at least two biosynthetic genes, one-third of which possess more than four biosynthetic genes. This study demonstrates the significant diversity of Actinobacteria in the Chukchi Shelf sediment and their potential for producing biologically active compounds and novel material for genetic manipulation or combinatorial biosynthesis.

  12. Phylogenetic diversity and biological activity of actinobacteria isolated from the Chukchi Shelf marine sediments in the Arctic Ocean.

    Science.gov (United States)

    Yuan, Meng; Yu, Yong; Li, Hui-Rong; Dong, Ning; Zhang, Xiao-Hua

    2014-03-01

    Marine environments are a rich source of Actinobacteria and have the potential to produce a wide variety of biologically active secondary metabolites. In this study, we used four selective isolation media to culture Actinobacteria from the sediments collected from the Chukchi Shelf in the Arctic Ocean. A total of 73 actinobacterial strains were isolated. Based on repetitive DNA fingerprinting analysis, we selected 30 representatives for partial characterization according to their phylogenetic diversity, antimicrobial activities and secondary-metabolite biosynthesis genes. Results from the 16S rRNA gene sequence analysis indicated that the 30 strains could be sorted into 18 phylotypes belonging to 14 different genera: Agrococcus, Arsenicicoccus, Arthrobacter, Brevibacterium, Citricoccus, Janibacter, Kocuria, Microbacterium, Microlunatus, Nocardioides, Nocardiopsis, Saccharopolyspora, Salinibacterium and Streptomyces. To our knowledge, this paper is the first report on the isolation of Microlunatus genus members from marine habitats. Of the 30 isolates, 11 strains exhibited antibacterial and/or antifungal activity, seven of which have activities against Bacillus subtilis and Candida albicans. All 30 strains have at least two biosynthetic genes, one-third of which possess more than four biosynthetic genes. This study demonstrates the significant diversity of Actinobacteria in the Chukchi Shelf sediment and their potential for producing biologically active compounds and novel material for genetic manipulation or combinatorial biosynthesis. PMID:24663116

  13. Trace elements and cathodoluminescence of detrital quartz in Arctic marine sediments – a new ice-rafted debris provenance proxy

    Directory of Open Access Journals (Sweden)

    A. Müller

    2013-07-01

    Full Text Available The records of ice-rafted debris (IRD provenance in the North Atlantic – Barents Sea allow the reconstruction of the spatial and temporal changes of ice-flow drainage patterns during glacial and deglacial periods. In this study a new approach to characterisation of the provenance of detrital quartz grains in the fraction > 500 μm of marine sediments offshore of Spitsbergen is introduced, utilizing scanning electron microscope backscattered electron and cathodoluminescence (CL imaging, combined with laser ablation inductively-coupled plasma mass spectrometry. Based on their micro-inclusions, CL and trace element characteristics the investigated IRD grains can be classified into five distinct populations. Three of the populations are indicative of potential IRD provenance provinces in the Storfjord area including Barentsøya and Egdeøya. The results imply that under modern (interglacial conditions IRD deposition along the western Spitsbergen margin is mainly governed by the East Svalbard Current controlling the ice-drift pattern. The presence of detrital quartz from local provinces, however, indicates that variations in IRD supply from western Spitsbergen may be quantified as well. In this pilot study it is demonstrated that this new approach applied on Arctic continental margin sediments, bears a considerable potential for the definition of the sources of IRD and thus of spatial/temporal changes in ice-flow drainage patterns during glacial/interglacial cycles.

  14. Environmental marine geology of the Arctic Ocean

    International Nuclear Information System (INIS)

    The Arctic Ocean and its ice cover are major regulators of Northern Hemisphere climate, ocean circulation and marine productivity. The Arctic is also very sensitive to changes in the global environment because sea ice magnifies small changes in temperature, and because polar regions are sinks for air pollutants. Marine geology studies are being carried out to determine the nature and rate of these environmental changes by study of modern ice and sea bed environments, and by interpretation of geological records imprinted in the sea floor sediments. Sea ice camps, an ice island, and polar icebreakers have been used to study both western and eastern Arctic Ocean basins. Possible early warning signals of environmental changes in the Canadian Arctic are die-back in Arctic sponge reefs, outbreaks of toxic dinoflagellates, and pesticides in the marine food chain. Eastern Arctic ice and surface waters are contaminated by freon and radioactive fallout from Chernobyl. At present, different sedimentary processes operate in the pack ice-covered Canadian polar margin than in summer open waters off Alaska and Eurasia. The geological records, however, suggest that a temperature increase of 1-4C would result in summer open water throughout the Arctic, with major changes in ocean circulation and productivity of waters off Eastern North America, and more widespread transport of pollutants from eastern to western Arctic basins. More studies of longer sediment cores are needed to confirm these interpretations, but it is now clear that the Arctic Ocean has been the pacemaker of climate change during the past 1 million years

  15. Environmental marine geology of the Arctic Ocean

    International Nuclear Information System (INIS)

    The Arctic Ocean and its ice cover are major regulators of Northern Hemisphere climate, ocean circulation and marine productivity. The Arctic is also very sensitive to changes in the global environment because sea ice magnifies small changes in temperature, and because polar regions are sinks for air pollutants. Marine geology studies are being carried out to determine the nature and rate of these environmental changes by study of modem ice and sea-bed environments, and by interpretation of geological records imprinted in the sea-floor sediments. Sea ice camps, an ice island, and polar icebreakers have been used to study both western and eastern Arctic Ocean basins. Possible early warning signals of environmental changes in the Canadian Arctic are die-back in Arctic sponge reefs, outbreaks of toxic dinoflagellates, and pesticides in the marine food chain. Eastern Arctic ice and surface waters are contaminated by freon and radioactive fallout from Chernobyl. At present, different sedimentary processes operate in the pack ice-covered Canadian polar margin than in summer open waters off Alaska and Eurasia. The geological records, however, suggest that a temperature increase of 1-4 degree C would result in summer open water throughout the Arctic, with major changes in ocean circulation and productivity of waters off Eastern North America, and more widespread transport of pollutants from eastern to western Arctic basins. More studies of longer sediment cores are needed to confirm these interpretations, but is is now clear that the Arctic Ocean has been the pacemaker of climate change during the past 1 million years

  16. Acetate, lactate, propionate, and isobutyrate as electron donors for iron and sulfate reduction in Arctic marine sediments, Svalbard

    DEFF Research Database (Denmark)

    Finke, Niko; Vandieken, Verona; Jørgensen, Bo Barker

    2007-01-01

    The contribution of volatile fatty acids (VFA) as e--donors for anaerobic terminal oxidation of organic carbon through iron and sulfate reduction was studied in Arctic fjord sediment. Dissolved inorganic carbon, Fe2+, VFA concentrations, and sulfate reduction were monitored in slurries from...

  17. Marine Transportation Implications of the Last Arctic Sea Ice Refuge

    Science.gov (United States)

    Brigham, L. W.

    2010-12-01

    Marine access is increasing throughout the Arctic Ocean and the 'Last Arctic Sea Ice Refuge' may have implications for governance and marine use in the region. Arctic marine transportation is increasing due to natural resource developemnt, increasing Arctic marine tourism, expanded Arctic marine research, and a general linkage of the Arctic to the gloabl economy. The Arctic Council recognized these changes with the release of the Arctic Marine Shipping Assessment of 2009. This key study (AMSA)can be viewed as a baseline assessment (using the 2004 AMSA database), a strategic guide for a host of stakeholders and actors, and as a policy document of the Arctic Council. The outcomes of AMSA of direct relevance to the Ice Refuge are within AMSA's 17 recommendations provided under three themes: Enhancing Arctic Marine Safety, Protecting Arctic People and the Environment, and Building the Arctic Marine Infrastructure. Selected recommendations of importance to the Ice Refuge include: a mandatory polar navigation code; identifying areas of heightened ecological and cultural significance; potential designation of special Arctic marine areas; enhancing the tracking and monitoring of Arctic marine traffic; improving circumpolar environmental response capacity; developing an Arctic search and rescue agreement; and, assessing the effects of marine transportation on marine mammals. A review will be made of the AMSA outcomes and how they can influence the governance, marine use, and future protection of this unique Arctic marine environment.

  18. Land-Based Marine Pollution in Arctic

    OpenAIRE

    Haile, Fitsum Gebreselassie

    2014-01-01

    Land-based pollution represents the single most important cause of marine pollution. The threat of land-based pollution to the marine environment is a serious one since it mainly affects coastal waters, which are sites of high biological productivity. The occurrence of high concentrations of pollutants in the Arctic environment has been a concern for many years.. Regional and international actions over the past two decades attempting to manage pollutants in the Arctic environment from land- b...

  19. The impact of temperature change on the activity and community composition of sulfate-reducing bacteria in arctic versus temperate marine sediments

    DEFF Research Database (Denmark)

    Robador, Alberto; Brüchert, Volker; Jørgensen, Bo Barker

    2009-01-01

    composition of sulfate-reducing bacteria were studied in the permanently cold sediment of north-western Svalbard (Arctic Ocean) and compared with a temperate habitat with seasonally varying temperature (German Bight, North Sea). Short-term 35S-sulfate tracer incubations in a temperature-gradient block...... (between -3.5°C and +40°C) were used to assess variations in sulfate reduction rates during the course of the experiment. Warming of arctic sediment resulted in a gradual increase of the temperature optima (Topt) for sulfate reduction suggesting a positive selection of psychrotolerant/mesophilic sulfate-reducing...... bacteria (SRB). However, high rates at in situ temperatures compared with maximum rates showed the predominance of psychrophilic SRB even at high incubation temperatures. Changing apparent activation energies (Ea) showed that increasing temperatures had an initial negative impact on sulfate reduction...

  20. Marine Arctic science capability making big strides

    Science.gov (United States)

    Johnson, Leonard; Brass, Garrett

    The profound influence of the Arctic Ocean on global environment, the rapid variability of Arctic processes, and the unresolved geology of the ocean floor have led to growing scientific interest in this region. Ongoing studies are investigating recent historical processes and modern processes such as changes in ocean circulation and ice cover patterns. Sediments beneath the Arctic Ocean record long- and short-term waxing and waning of the cryosphere in the Northern Hemisphere and its linkages to bottom water renewal and faunal adaptation. Underlying basement rocks reflect the tectonic history of the ocean basin, including its ridges and plateaus, which are unsampled and of unknown composition and origin. The vulnerability of Arctic populations to environmental problems makes the need to understand the region even more compelling (see, for example, Arctic Monitoring and Assessment Programme, 1997; also see Web site http://www.grida.no/amap).

  1. Chytrids dominate arctic marine fungal communities.

    Science.gov (United States)

    Hassett, B T; Gradinger, R

    2016-06-01

    Climate change is altering Arctic ecosystem structure by changing weather patterns and reducing sea ice coverage. These changes are increasing light penetration into the Arctic Ocean that are forecasted to increase primary production; however, increased light can also induce photoinhibition and cause physiological stress in algae and phytoplankton that can favour disease development. Fungi are voracious parasites in many ecosystems that can modulate the flow of carbon through food webs, yet are poorly characterized in the marine environment. We provide the first data from any marine ecosystem in which fungi in the Chytridiomycota dominate fungal communities and are linked in their occurrence to light intensities and algal stress. Increased light penetration stresses ice algae and elevates disease incidence under reduced snow cover. Our results show that chytrids dominate Arctic marine fungal communities and have the potential to rapidly change primary production patterns with increased light penetration. PMID:26754171

  2. Submarine Landslides in Arctic Sedimentation: Canada Basin

    Science.gov (United States)

    Mosher, David C.; Shimeld, John; Hutchinson, Deborah R.; Lebedova-Ivanova, N; Chapman, C.

    2016-01-01

    Canada Basin of the Arctic Ocean is the least studied ocean basin in the World. Marine seismic field programs were conducted over the past 6 years using Canadian and American icebreakers. These expeditions acquired more than 14,000 line-km of multibeam bathymetric and multi-channel seismic reflection data over abyssal plain, continental rise and slope regions of Canada Basin; areas where little or no seismic reflection data existed previously. Canada Basin is a turbidite-filled basin with flat-lying reflections correlateable over 100s of km. For the upper half of the sedimentary succession, evidence of sedimentary processes other than turbidity current deposition is rare. The Canadian Archipelago and Beaufort Sea margins host stacked mass transport deposits from which many of these turbidites appear to derive. The stratigraphic succession of the MacKenzie River fan is dominated by mass transport deposits; one such complex is in excess of 132,000 km2 in area and underlies much of the southern abyssal plain. The modern seafloor is also scarred with escarpments and mass failure deposits; evidence that submarine landsliding is an ongoing process. In its latest phase of development, Canada Basin is geomorphologically confined with stable oceanographic structure, resulting in restricted depositional/reworking processes. The sedimentary record, therefore, underscores the significance of mass-transport processes in providing sediments to oceanic abyssal plains as few other basins are able to do.

  3. Evolution of the Arctic Calanus complex: an Arctic marine avocado?

    OpenAIRE

    Berge, Jørgen; Gabrielsen, Tove M.; Mark A Moline; Renaud, Paul

    2012-01-01

    Before man hunted the large baleen whales to near extinction by the end of the nineteenth century, Arctic ecosystems were strongly influenced by these large predators. Their main prey were zooplankton, among which the calanoid copepod species of the genus Calanus, long considered key elements of polar marine ecosystems, are particularly abundant. These herbivorous zooplankters display a range of adaptations to the highly seasonal environments of the polar oceans, most notably extensive energy...

  4. 3D seismic imaging of marine gas hydrates in Arctic sediments of the Vestnesa Ridge off the W-Svalbard margin

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, C.J.; Bunz, S.; Hustoft, S.; Mienert, J. [Tromso Univ., Tromso (Norway). Dept. of Geology

    2008-07-01

    A gas hydrate and fluid flow dominated sediment drift system at the Vestnesa Ridge offshore W-Svalbard was characterized using high-resolution 3-D seismic data. This ridge represents one of the northernmost gas hydrate provinces that exist along Arctic continental margins. Detailed images revealed seabed pockmarks connected to sub-seabed chimneys that pierce through stratified sediments. The base of the gas hydrate stability zone (BGHSZ) is evident at about 200 ms TWT below seafloor as indicated by a bottom simulating reflector. Increased amplitudes beneath the BGHSZ indicate the existence of large amounts of free gas in the sediment pore space. Variations in lateral amplitude indicate a geological control on the free gas distributions rather than pressure and temperature conditions. The seismic surveys also revealed the internal structure of the acoustic chimneys that act as conduits for fluids and gases rising from greater depth to the seabed. It was suggested that the combination of authigenic carbonate and gas hydrate formation may cause shallow high-reflectivity above the BGHSZ. The fluid flow processes that result in the multifracturing of sediments play a significant role in the evolution of the chimney structures in a gas hydrated sedimentary environment. 21 refs., 7 figs.

  5. Biodiversity of Arctic marine ecosystems and responses to climate change

    DEFF Research Database (Denmark)

    Michel, C.; Bluhm, B.; Gallucci, V.;

    2012-01-01

    . These changes have important impacts on the chemical and biological processes that are at the root of marine food webs, influencing their structure, function and biodiversity. Here we summarise current knowledge on the biodiversity of Arctic marine ecosystems and provide an overview of fundamental factors...... that structure ecosystem biodiversity in the Arctic Ocean. We also discuss climateassociated effects on the biodiversity of Arctic marine ecosystems and discuss implications for the functioning of Arctic marine food webs. Based on the complexity and regional character of Arctic ecosystem reponses...

  6. Marine meiofauna, carbon and nitrogen mineralization in sandy and soft sediments of Disko Bay, West Greenland

    DEFF Research Database (Denmark)

    Rysgaard, S.; Christensen, P.B.; Sørensen, Martin Vinther;

    2000-01-01

    and was, together with organotrophic O-2 respiration, the most important pathway for carbon mineralization within these sediments. The obtained process rates were comparable to mineralization rates from much warmer localities, suggesting that benthic mineralization in arctic marine environments...

  7. Alaska Arctic marine fish ecology catalog

    Science.gov (United States)

    Thorsteinson, Lyman K.; Love, Milton S.

    2016-08-08

    The marine fishes in waters of the United States north of the Bering Strait have received new and increased scientific attention over the past decade (2005–15) in conjunction with frontier qualities of the region and societal concerns about the effects of Arctic climate change. Commercial fisheries are negligible in the Chukchi and Beaufort Seas, but many marine species have important traditional and cultural values to Alaska Native residents. Although baseline conditions are rapidly changing, effective decisions about research and monitoring investments must be based on reliable information and plausible future scenarios. For the first time, this synthesis presents a comprehensive evaluation of the marine fish fauna from both seas in a single reference. Although many unknowns and uncertainties remain in the scientific understanding, information presented here is foundational with respect to understanding marine ecosystems and addressing dual missions of the U.S. Department of the Interior for energy development and resource conservation. 

  8. Alaska Arctic marine fish ecology catalog

    Science.gov (United States)

    2016-01-01

    The marine fishes in waters of the United States north of the Bering Strait have received new and increased scientific attention over the past decade (2005–15) in conjunction with frontier qualities of the region and societal concerns about the effects of Arctic climate change. Commercial fisheries are negligible in the Chukchi and Beaufort Seas, but many marine species have important traditional and cultural values to Alaska Native residents. Although baseline conditions are rapidly changing, effective decisions about research and monitoring investments must be based on reliable information and plausible future scenarios. For the first time, this synthesis presents a comprehensive evaluation of the marine fish fauna from both seas in a single reference. Although many unknowns and uncertainties remain in the scientific understanding, information presented here is foundational with respect to understanding marine ecosystems and addressing dual missions of the U.S. Department of the Interior for energy development and resource conservation. 

  9. Black carbon in marine sediments

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.; Van Breugel, P.

    1999-01-01

    Concentrations of black carbon were determined for a number of marine sediments. A comparison of black carbon based on thermal oxidation and hot concentrated nitric acid pretreatments revealed that the latter significantly overestimates combustion derived carbon phases. Black carbon accounts for abo

  10. Radionuclide interactions with marine sediments

    International Nuclear Information System (INIS)

    A critical review of the literature on the subject of the interactions of radionuclides with marine sediments has been carried out. On the basis of the information available, an attempt has been made to give ranges and 'best estimates' for the distribution ratios between seawater and sediments. These estimates have been based on an understanding of the sediment seawater system and the porewater chemistry and mineralogy. Field measurements, laboratory measurements and estimates based on stable-element geochemical data are all taken into account. Laboratory measurements include distribution-ratio and diffusion-coefficient determinations. The elements reviewed are carbon, chlorine, calcium, nickel, selenium, strontium, zirconium, niobium, technetium, tin, iodine, caesium, lead, radium, actinium, thorium, protactinium, uranium, neptunium, plutonium, americium and curium. (author)

  11. A quantitative x-ray diffraction inventory of volcaniclastic inputs into the marine sediment archives off Iceland: a contribution to the Volcanoes in the Arctic System programme

    Directory of Open Access Journals (Sweden)

    Dennis D. Eberl

    2013-02-01

    Full Text Available This paper re-evaluates how well quantitative x-ray diffraction (qXRD can be used as an exploratory method of the weight percentage (wt% of volcaniclastic sediment, and to identify tephra events in marine cores. In the widely used RockJock v6 software programme, qXRD tephra and glass standards include the rhyodacite White River tephra (Alaska, a rhyolitic tephra (Hekla-4 and the basaltic Saksunarvatn tephra. Experiments of adding known wt% of tephra to felsic bedrock samples indicated that additions ≥10 wt% are accurately detected, but reliable estimates of lesser amounts are masked by amorphous material produced by milling. Volcaniclastic inputs range between 20 and 50 wt%. Primary tephra events are identified as peaks in residual qXRD glass wt% from fourth-order polynomial fits. In cores where tephras have been identified by shard counts in the >150 µm fraction, there is a positive correlation (validation with peaks in the wt% glass estimated by qXRD. Geochemistry of tephra shards confirms the presence of several Hekla-sourced tephras in cores B997-317PC1 and -319PC2 on the northern Iceland shelf. In core B997-338 (north-west Iceland, there are two rhyolitic tephras separated by ca. 100 cm with uncorrected radiocarbon dates on articulated shells of around 13 000 yr B.P. These tephras may be correlatives of the Borrobol and Penifiler tephras found in Scotland. The number of Holocene tephra events per 1000 yr was estimated from qXRD on 16 cores and showed a bimodal distribution with an increased number of events in both the late and early Holocene.

  12. Adapting Governance and Regulation of the Marine Arctic

    NARCIS (Netherlands)

    Molenaar, Erik

    2014-01-01

    The Arctic is currently undergoing change at a pace many would not have considered possible just a decade or so ago. It is therefore reasonable to argue that while the international law and policy regime for the governance and regulation of the marine Arctic may have been adequate for an ice-dominat

  13. Towards Arctic Resource Governance of Marine Invasive Species

    DEFF Research Database (Denmark)

    Kourantidou, Melina; Kaiser, Brooks; Fernandez, Linda

    2015-01-01

    Scientific and policy-oriented publications highlighting the magnitude of uncertainty in the changing Arctic and the possibilities for effective regional governance are proliferating, yet it remains a challenging task to examine Arctic marine biodiversity. Limited scientific data are currently av...

  14. Comparative analysis of marine paleogene sections and biota from West Siberia and the Arctic Region

    Science.gov (United States)

    Akhmet'ev, M. A.; Zaporozhets, N. I.; Iakovleva, A. I.; Aleksandrova, G. N.; Beniamovsky, V. N.; Oreshkina, T. V.; Gnibidenko, Z. N.; Dolya, Zh. A.

    2010-12-01

    The analysis of the main biospheric events that took place in West Siberia and the Arctic region during the Early Paleogene revealed the paleogeographic and paleobiogeographic unity of marine sedimentation basins and close biogeographic relations between their separate parts. Most biotic and abiotic events of the first half of the Paleogene in the Arctic region and West Siberia were synchronous, unidirectional, and interrelated. Shelf settings, sedimentation breaks, and microfaunal assemblages characteristic of these basins during the Paleogene are compared. The comparative analysis primarily concerned events of the Paleocene-Eocene thermal maximum (PETM) and beds with Azolla (aquatic fern). The formation of the Eocene Azolla Beds in the Arctic region and West Siberia was asynchronous, although it proceeded in line with a common scenario related to the development of a system of estuarine-type currents in a sea basin partly isolated from the World Ocean.

  15. Long distance electron transmission in marine sediment

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Nielsen, Lars Peter

    Geochemical observations in marine sediment have recently shown that electric currents may intimately couple spatially separated biogeochemical processes like oxygen reduction at the sediment surface and hydrogen sul-phide oxidation in anoxic layers centimeters below 1. Further experimental studies...... in the system. Long distance electron transmission may flourishes in marine sediments exposed to tran-sient oxygen depletion, leaving distinct signatures of such events in the geological record....

  16. Legal Instruments for Marine Sanctuary in the High Arctic

    Directory of Open Access Journals (Sweden)

    Kathleen Morris

    2016-05-01

    Full Text Available In response to heightened threat to Arctic marine biodiversity due to polar ice melt, the following paper seeks to use qualitative secondary research to analyze existing anthropogenic threat to Arctic marine life and to evaluate current efforts on the part of the Arctic Council to protect biodiversity through a network of state-created marine protected areas (MPAs. We conclude that the current method for MPA creation fails to offer adequate pathways for creation of MPAs in Areas Beyond National Jurisdiction (ABNJ, the high seas which fall beyond individual countries’ exclusive economic zones (EEZs. Thus, our central research question is to determine what legal basis and mechanisms exist for the creation of MPAs in ABNJs, with particular focus on the Arctic marine environment. In keeping with The United Nations Convention on Biological Diversity’s (UNCBD precautionary approach, along with specific rules embodied within The United Nations Convention on the Law of the Sea (UNCLOS, we find a basis for creation of MPAs in the ABNJ. The text evaluates findings from the Boulogne-sur-Mer international conference of 2011 to suggest that such MPA creation in ABNJ could be approached via four pathways: regional agreement, UNCLOS implementing agreement, UNCBD additional protocol, or an Arctic Sanctuary modeled on the Antarctic Treaty. While we explore all four options, we argue that, due to geopolitical constraints, a comprehensive regional agreement offers the best path to High Arctic MPA creation.

  17. Bacterial and archaeal community structures in the Arctic deep-sea sediment

    Institute of Scientific and Technical Information of China (English)

    LI Yan; LIU Qun; LI Chaolun; DONG Yi; ZHANG Wenyan; ZHANG Wuchang; XIAO Tian

    2015-01-01

    Microbial community structures in the Arctic deep-sea sedimentary ecosystem are determined by organic matter input, energy availability, and other environmental factors. However, global warming and earlier ice-cover melting are affecting the microbial diversity. To characterize the Arctic deep-sea sediment microbial diversity and its rela-tionship with environmental factors, we applied Roche 454 sequencing of 16S rDNA amplicons from Arctic deep-sea sediment sample. Both bacterial and archaeal communities’ richness, compositions and structures as well as tax-onomic and phylogenetic affiliations of identified clades were characterized. Phylotypes relating to sulfur reduction and chemoorganotrophic lifestyle are major groups in the bacterial groups;while the archaeal community is domi-nated by phylotypes most closely related to the ammonia-oxidizing Thaumarchaeota (96.66%) and methanogenic Euryarchaeota (3.21%). This study describes the microbial diversity in the Arctic deep marine sediment (>3 500 m) near the North Pole and would lay foundation for future functional analysis on microbial metabolic processes and pathways predictions in similar environments.

  18. Arctic Marine Transportation Program 1979-1986

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The purpose of this program was to collect data relevant to developing year-round transportation capabilities in the Arctic Ocean. The US Maritime Administration...

  19. Denitrification in marine sediments: A model study

    NARCIS (Netherlands)

    Middelburg, J.J.; Soetaert, K.E.R.; Herman, P.M.J.; Heip, C.H.R.

    1996-01-01

    The rate and factors controlling denitrification in marine sediments have been investigated using a prognostic diagenetic model. The model is forced with observed carbon fluxes, bioturbation and sedimentation rates, and bottom water conditions. It can reproduce rates of aerobic mineralization, denit

  20. Sterols and Stanols Preserved in Pond Sediments Track Seabird Biovectors in a High Arctic Environment.

    Science.gov (United States)

    Cheng, Wenhan; Sun, Liguang; Kimpe, Linda E; Mallory, Mark L; Smol, John P; Gallant, Lauren R; Li, Jinping; Blais, Jules M

    2016-09-01

    Seabirds are major vertebrates in the coastal ecosystems of the Canadian High Arctic, where they transport substantial amounts of marine-derived nutrients and pollutants from oceans to land by depositing guano and stomach oils to their nesting area, which often includes nearby freshwater ponds. Here we present novel indicators for evaluating the impact of seabirds on freshwater ecosystems. The ratio of cholesterol/(cholesterol + sitosterol) in pond sediments showed significant enrichment near a nesting colony of northern fulmars (Fulmarus glacialis) and was significantly correlated with ornithogenic enrichment of sediment as determined by sedimentary δ(15)N. The sterol ratio was also correlated with several bioaccumulative persistent organic pollutants (POPs), suggesting its usefulness in tracking biovector enrichment of contaminants. Human-derived epicoprostanol was also analyzed in the sediments, and its relationship with an abandoned, prehistoric camp was recorded, suggesting its potential as a tracer of prehistoric human activities in the Arctic. Sterols and stanols preserved in sediments appear to be useful geochemical tools that will inform our understanding of migratory species and the presence of prehistoric human populations in the Arctic, and possibly other animal populations. PMID:27409713

  1. Psychrophilic sulfate-reducing bacteria isolated from permanently cold Arctic marine sediments: description of Desulfofrigrus oceanense gen. nov., sp nov., Desulfofrigus fragile sp nov., Desulfofaba gelida gen. nov., sp nov., Desulfotalea psychrophila gen. nov., sp nov and Desulfotalea arctica sp

    DEFF Research Database (Denmark)

    Knoblauch, C.; Sahm, K.; Jørgensen, BB

    1999-01-01

    Five psychrophilic, Gram-negative, sulfate-reducing bacteria were isolated from marine sediments off the coast of Svalbard. All isolates grew at the in situ temperature of -1.7 degrees C. In batch cultures, strain PSv29(T) had the highest growth rate at 7 degrees C, strains ASv26(T) and LSv54(T...

  2. Molecular organic geochemistry of ornithogenic sediment from Svalbard, Arctic

    Institute of Scientific and Technical Information of China (English)

    Wang Jianjun; Sun Liguang

    2009-01-01

    The molecular biomarker compositions of the ornithogenic sediments (YN), from Svalbard, Arctic were investigated. The results showed that n-alkanes had a bimodal pattern and their odd-even preference was not obvious. The alkanes contained unresolved complex mixtures (UCM) and relatively high levels of pristine and retene, indicating pollution from the nearby coal mines. The n-alkanols in the sediments had even-to-odd preference, and they might originate mainly from modern biota. Sistosterol, the main sterol in herbivores feces, was the dominant sterol, indicating that sitosterol might be a good biomarker of input from the birds feces in the sediments. The fatty acids of the sediments showed acid. The α-hydroxyl acids and ω-hydroxyl fatty acids were also detected in the sediments. In summary, the organic matters in the YN sediments were from the adjacent coal mines, bird feces, and plants.

  3. Controls on stable sulfur isotope fractionation during bacterial sulfate reduction in Arctic sediments

    DEFF Research Database (Denmark)

    Bruchert, V.; Knoblauch, C.; Jørgensen, BB

    2001-01-01

    Sulfur isotope fractionation experiments during bacterial sulfate reduction were performed with recently isolated strains of cold-adapted sulfate-reducing bacteria from Arctic marine sediments with year-round temperatures below 2 degreesC. The bacteria represent quantitatively important members...... parts per thousand and 8 parts per thousand above 25 degreesC, respectively. In absence of significant differences in sulfate reduction rates in the high and low temperature range, respectively, we infer that different genera of sulfate-reducing bacteria dominate the sulfate-reducing bacterial community...

  4. Low viral predation pressure in cold hypersaline Arctic sediments and limits on lytic replication.

    Science.gov (United States)

    Colangelo-Lillis, Jesse; Wing, Boswell A; Whyte, Lyle G

    2016-04-01

    Viruses are ubiquitous drivers of microbial ecology and evolution and contribute to biogeochemical cycling. Attention to these attributes has been more substantial for marine viruses than viruses of other environments. Microscopy-based investigation of the viral communities from two cold, hypersaline Arctic springs was undertaken to explore the effects of these conditions on microbe-viral ecology. Sediments and water samples were collected along transects from each spring, from anoxic spring outlets through oxygenated downstream channels. Viral abundance, virus-microbe ratios and modelled virus-microbe contact rates were lower than comparable aqueous and sedimentary environments and most similar to deep subsurface sediments. No individual cell from either spring was visibly infected. Viruses in these springs appear to play a smaller role in controlling microbial populations through lytic activity than in marine water column or surface sedimentary environments. Relief from viral predation indicates the microbial communities are primarily controlled by nutrient limitation. The similarity of these springs to deep subsurface sediments suggests a biogeographic divide in viral replication strategy in marine sediments. PMID:26743115

  5. Chemical pollution in the Arctic and Sub-Arctic marine ecosystems: an overview of current knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Savinova, T.N.; Gabrielsen, G.W.; Falk-Petersen, S.

    1995-02-01

    This report is part of a research project in the framework of the Norwegian-Russian Environmental Cooperation, which was initiated in 1991 to elucidate the present status of environmental contaminants in the highly sensitive Arctic aquatic ecosystem, with special focus on sea birds. Although these ecosystems are the least polluted areas in the world, they are contaminated. The main pathways of contamination into Arctic and sub-Arctic marine ecosystems are atmospheric transport, ocean currents and rivers and in some areas, dumping and ship accidents. A literature survey reveals: (1) there is a lack of data from several trophic levels, (2) previous data are difficult to compare with recent data because of increased quality requirement, (3) not much has been done to investigate the effects of contaminants on the cellular level, at individual or population levels. 389 refs., 7 figs., 32 tabs.

  6. Flocculation alters the distribution and flux of melt-water supplied sediments and nutrients in the Arctic

    DEFF Research Database (Denmark)

    Markussen, Thor Nygaard; Andersen, Thorbjørn Joest; Ernstsen, Verner Brandbyge;

    environment but comparatively little is known about the flocculation processes in the Arctic. We investigated flocculation dynamics from a melt-water river in the inner Disko Fjord, West Greenland. A novel, laser-illuminated camera system significantly improved the particle size measurement capabilities......In the Arctic, thawing permafrost and increased melting of glaciers are important drivers for changes in fine-grained sediment supply and biogeochemical fluxes from land to sea. Flocculation of particles is a controlling factor for the magnitude of fluxes and deposition rates in the marine...

  7. FRAM - FRontiers in Arctic marine Monitoring: Permanent Observations in a Gateway to the Arctic Ocean

    Science.gov (United States)

    Soltwedel, Thomas

    2015-04-01

    Our ability to understand the complex interactions of biological, chemical, physical, and geological processes in the ocean is still limited by the lack of integrative and interdisciplinary observation infrastructures. The main purpose of the open-ocean infrastructure FRAM (FRontiers in Arctic marine Monitoring) is permanent presence at sea, from surface to depth, for the provision of near real-time data on climate variability and ecosystem change in an Arctic marine environment. The Alfred-Wegener-Institut I Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), together with partner institutes in Germany and Europe, aims at providing such infrastructure for the polar ocean as a major contribution to international efforts towards comprehensive Global Earth Observation. The FRAM Ocean Observing System targets the gateway between the North Atlantic and the Central Arctic, representing a highly climate-sensitive and rapidly changing region of the Earth system. It will serve national and international tasks towards a better understanding of the effects of change in ocean circulation, water mass properties and sea-ice retreat on Arctic marine ecosystems and their main functions and services. FRAM integrates and develops already existing observatories, i.e. the oceanographic mooring array HAFOS (Hybrid Arctic/Antarctic Float Observing System) and the Long-Term Ecological Research (LTER) site HAUSGARTEN. It will implement existing and next-generation sensors and observatory platforms, allowing synchronous observation of relevant ocean variables, as well as the study of physical, chemical and biological processes in the water column and at the seafloor. Experimental and event-triggered platforms will complement observational platforms. Products of the infrastructure are continuous long-term data with appropriate resolution in space and time, as well as ground-truthing information for ocean models and remote sensing.

  8. Radionuclide sorption by marine sediments

    International Nuclear Information System (INIS)

    The effect of the solid/solution ratio on distribution ratios measured using a standard batch technique was investigated. Two different deep-sea sediments and the actinides americium, neptunium and plutonium were studied. It is shown that the apparent drop in distribution ratio with increasing sediment concentration can frequently be explained by the presence of a small amount of non-separable or 'low-Rsub(d)' species and that by measuring the Rsub(d) at different solid/solution ratios it is possible to estimate the proportion of low-Rsub(d) species present. These may be colloids or stable complexes. Plutonium exhibited anomalous behaviour with the high-carbonate sediment and the distribution ratio dropped from > 104 to 102 as the solid/soln ratio increased from 2g/l to 20g/l. At high sediment concentrations the plutonium in solution was mainly in the oxidised Pu(V + VI) form and it is postulated that Pu-VI carbonates were the main species present. (author)

  9. Magnesium Isotopic Composition of Subducting Marine Sediments

    Science.gov (United States)

    Hu, Y.; Teng, F. Z.; Plank, T. A.; Huang, K. J.

    2015-12-01

    Subducted marine sediments have recently been called upon to explain the heterogeneous Mg isotopic composition (δ26Mg, ‰) found in mantle wehrlites (-0.39 to +0.09 [1]) in the context of a homogeneous mantle (-0.25 ± 0.07 [2]). However, no systematic measurements of δ26Mg on marine sediments are currently available to provide direct support to this model. To characterize the Mg inputs to global subduction zones, we measured δ26Mg data for a total of 90 marine sediments collected from 12 drill sites outboard of the world's major subduction zones. These sediments span a 1.73‰ range in δ26Mg. The detritus-dominated sediments have δ26Mg (-0.59 to +0.53) comparable to those of weathered materials on continents (e.g. -0.52 to +0.92 [3]), while the calcareous oozes yield δ26Mg (as light as -1.20) more similar to the seawater value (-0.83 [4]). The negative correlation between δ26Mg and CaO/Al2O3 in these sediments indicates the primary control of mineralogy over the Mg isotopic distribution among different sediment types, as carbonates are enriched in light Mg isotopes (-5.10 to -0.40 [5]) whereas clay-rich weathering residues generally have heavier δ26Mg (e.g. up to +0.65 in saprolite [6]). In addition, chemical weathering and grain-size sorting drive sediments to a heavier δ26Mg, as indicated by the broad positive trends between δ26Mg with CIA (Chemical Index of Alteration [7]) and Al2O3/SiO2, respectively. Collectively, the arc systems sampled in this study represent ~30% of global arc length and the extrapolated global Mg flux of subducting marine sediments accounts for ~9% of the yearly Mg riverine input with a flux-weighted average δ26Mg at -0.26. Subduction of these heterogeneous sediments may not cause significant mantle heterogeneity on a global scale, but the highly variable Mg fluxes and δ26Mg of sediments delivered to different trenches are capable of producing local mantle variations. Volcanic rocks sourced from these mantle domains are thus

  10. Mercury in dated Greenland marine sediments

    DEFF Research Database (Denmark)

    Asmund, G.; Nielsen, S.P.

    2000-01-01

    Twenty marine sediment cores from Greenland were analysed for mercury, and dated by the lead-210 method. In general the cores exhibit a mercury profile with higher mercury concentrations in the upper centimetres of the core. The cores were studied by linear regression of In Hg vs, age...... of the sediment for the youngest 100 years. As a rule the mercury decreased with depth in the sediment with various degrees of significance. The increase of the mercury flux during the last 100 years is roughly a doubling. The increase may be of anthropogenic origin as it is restricted to the last 100 years....... In four cores the concentration of manganese was found also to increase in the top layers indicating diagenesis. In the other cases the higher concentrations were not accompanied by higher manganese concentrations. The mercury flux to the sediment surface was generally proportional to the Pb-210 flux...

  11. AMOP (Arctic Marine Oil Spill Program) studies reviewed

    Energy Technology Data Exchange (ETDEWEB)

    1978-06-05

    A discussion of the Arctic Marine Oil Spill Program organized in 1976 by the Canadian Federal Government includes: an Arctic Atlas compiled by Fenco Consultants Ltd. to give background information necessary for developing marine oil spill countermeasures for the Arctic north of 60/sup 0/ including the west Greenland coast and the Labrador shelf (geology, meteorology and oceanography, ice conditions, biology, and social factors); program in emergency transport of spill-combatting equipment; and the factors which influence the choice of conveyance, i.e., accessibility of the site, urgency for response, and quantity of material required; laboratory studies involving the release of oil under artificial sea ice in simulated ice formation and decay purposes to determine the interaction of crude oil and first-year sea ice; inability of companies and government to control a major spill in the Labrador Sea because of poor and inadequate transport facilities, communications, and navigational aids, severe environmental conditions, and logistics problems; and studies on the effects of oil-well blowouts in deep water, including formation of oil and gas hydrates, design of oil skimmers, the use of hovercraft, and specifications for an airborne multisensor system for oil detection in ice-infested waters.

  12. Sampling and analysis in the Arctic marine benthic environment. Vol. 2. Guide to practice

    Energy Technology Data Exchange (ETDEWEB)

    1985-03-01

    There is an increasing requirement for environmental information on Arctic marine sediments because of natural resource development, particularly offshore hydrocarbon exploration and associated proposed transport mechanisms. At the same time, it is recognized that methods that have been used for collection, analysis and data reporting need improvement if the data are to have long term value. This is the second part of a study to produce a guide for managers and planners involved in the collection and analysis of environmental data from marine sediments in Arctic regions. The first phase of this study (Volume 1) reviewed existing methods and was intended to serve as a background document to the present report. The format is designed to outline in a step-by-step manner the factors to be considered and offers suggestions as to possible methods to achieve various results. This guide includes sampling strategy and means of quality control, sampling and subsampling methods for chemical analysis, sampling methods for benthos, means of sample preservation and storage, sampling logistics (transport, positioning and sampling from ice), methods of sample analysis for metals, organics, grain size, Pb-210 dating, methods of laboratory quality assurance and methods for the analysis of benthic data. 319 refs., 14 figs., 44 tabs.

  13. Modeling sediment deposition from marine outfall jets.

    Science.gov (United States)

    Terfous, Abdelali; Chiban, Samia; Ghenaim, Abdellah

    2016-08-01

    This paper presents a two-dimensional model to study the sediment deposition from marine outfall jets. The introduced unidirectional coupling (fluid-sediment) is an appropriate choice in the case of low-concentrated particle-laden jets such as municipal wastewater discharge, where the concentration of particles is small enough and does not affect the hydrodynamic development of the jet in the nearfield. The sedimentation model takes advantage of the preferential concentration phenomenon. The deposition criterion states that the deposition of sediments begins when the vertical component of the entrainment velocity becomes smaller than the settling velocity. Once the deposition process begins, it is controlled by the settling velocity, entrainment velocity, volume flux, and sediment concentration. The deposition along the jet trajectory is expressed by an ordinary differential equation coupled with the liquid phase equations. Experiments of Lane-Serff and Moran [Sedimentation from Buoyant jets. J Hyd Eng. 2005;131(3):166-174], Cuthbertson and Davies [Deposition from particle-laden, round, turbulent, horizontal, buoyant jets in stationary and coflowing receiving fluids. J Hydr Eng. 2008;134(4):390-402], and Lee [Mixing of horizontal sediment laden jets [dissertation]. Hong Kong: University of Hong Kong; 2010], chosen from bibliography, are used to validate the model. These experiments cover the cases of horizontal and inclined buoyant jets in stationary ambient, horizontal buoyant jets in co-flow current and nonbuoyant horizontal jets in stationary ambient. Good agreement between the experiments and the obtained simulations is revealed. PMID:26732467

  14. Desulfuromonas svalbardensis sp. nov. and Desulfuromusa ferrireducens sp. nov., psychrophilic, Fe(III)-reducing bacteria isolated from Arctic sediments, Svalbard

    DEFF Research Database (Denmark)

    Vandieken, Verona; Mussmann, Marc; Niemann, Helge;

    2006-01-01

    Two psychrophilic, Gram-negative, rod-shaped, motile bacteria (strains 112T and 102T) that conserved energy from dissimilatory Fe(III) reduction concomitant with acetate oxidation were isolated from permanently cold Arctic marine sediments. Both strains grew at temperatures down to -2 degrees C...

  15. Nonlinear compressional waves in marine sediments

    Science.gov (United States)

    McDonald, B. Edward

    2005-09-01

    A theory for nonlinear waves in marine sediments must account for the presence of a granular frame filled with water and possibly gas bubbles. When grains are in full contact, the stress-strain relation for the sediment contains a contribution varying as strain to the power 3/2, referred to as the Hertz force. The quadratic nonlinearity parameter derived from the second pressure derivative with respect to density thus diverges in the limit of small strain. We present a simple nonlinear wave equation model (a variant of the NPE) for compressional waves in marine sediments that avoids Taylor expansion and the problem of diverging nonlinearity parameter. An equation of state for partially consolidated sediments is derived from consolidation test results. Pressure is found to increase with overdensity to the power 5/2, indicating an increase in the number of contacts per grain as density increases. Numerical results for nonlinear compressional waves show agreement with analytic self-similar profiles derived from the nonlinear wave equation. [Work supported by the ONR.

  16. Biodegradation of crude oil in different types of marine sediment

    International Nuclear Information System (INIS)

    An active oil-oxidizing bacterium, named Nap C was isolated from the sediment sample of Port Dickson coastal area for this study. Nap C is a gram negative, rod shape marine bacterium. It forms spore when the condition is not favorable. Three different types of treated marine sediment; sand, silt and clay were used in this study. The degradation of Malaysian Tapis A crude oil in the different types of marine sediment were assessed. Silt type of marine sediment was found to sustain highest biodegradation compared to clay type and sand type. 8.6.67% of the Malaysian Tapis A crude oil was degraded in silt type of marine sediment within 10 days of incubation. Where as there were only 60% and 73% of the Malaysian Tapis A crude oil was degraded in sand and clay type of marine sediment respectively. Microbial biomass estimation in the sediment was estimated by indirect phospholipid enumeration technique. (author)

  17. Polychlorinated naphthalenes (PCNs) in sub-Arctic and Arctic marine mammals, 1986–2009

    International Nuclear Information System (INIS)

    A selection of PCN congeners was analyzed in pooled blubber samples of pilot whale (Globicephala melas), ringed seal (Phoca hispida), minke whale (Balaenoptera acutorostrata), fin whale (Balaenoptera physalus), harbour porpoise (Phocoena phocoena), hooded seal (Cystophora cristata) and Atlantic white-sided dolphin (Lagenorhynchus acutus), covering a time period of more than 20 years (1986–2009). A large geographical area of the North Atlantic and Arctic areas was covered. PCN congeners 48, 52, 53, 66 and 69 were found in the blubber samples between 0.03 and 5.9 ng/g lw. Also PCBs were analyzed in minke whales and fin whales from Iceland and the total PCN content accounted for 0.2% or less of the total non-planar PCB content. No statistically significant trend in contaminant levels could be established for the studied areas. However, in all species except minke whales caught off Norway the lowest ∑PCN concentrations were found in samples from the latest sampling period. - Highlights: ► PCN concentrations are described in a wide variety of marine mammal species. ► A large geographical area of the North Atlantic and Arctic areas is covered. ► Pooled blubber samples covering a time period of 23 years are evaluated. ► Species- and geographic-dependent PCN congener distribution is seen. ► A decrease in the PCN load is indicated in the studied areas in recent years. - Analysis of PCNs in seven marine mammal species sampled over a 23 year period indicates a decline in the PCN load in sub-Arctic and Arctic areas in recent years.

  18. Freshwater and its role in the Arctic Marine System: Sources, disposition, storage, export, and physical and biogeochemical consequences in the Arctic and global oceans

    Science.gov (United States)

    Carmack, E. C.; Yamamoto-Kawai, M.; Haine, T. W. N.; Bacon, S.; Bluhm, B. A.; Lique, C.; Melling, H.; Polyakov, I. V.; Straneo, F.; Timmermans, M.-L.; Williams, W. J.

    2016-03-01

    The Arctic Ocean is a fundamental node in the global hydrological cycle and the ocean's thermohaline circulation. We here assess the system's key functions and processes: (1) the delivery of fresh and low-salinity waters to the Arctic Ocean by river inflow, net precipitation, distillation during the freeze/thaw cycle, and Pacific Ocean inflows; (2) the disposition (e.g., sources, pathways, and storage) of freshwater components within the Arctic Ocean; and (3) the release and export of freshwater components into the bordering convective domains of the North Atlantic. We then examine physical, chemical, or biological processes which are influenced or constrained by the local quantities and geochemical qualities of freshwater; these include stratification and vertical mixing, ocean heat flux, nutrient supply, primary production, ocean acidification, and biogeochemical cycling. Internal to the Arctic the joint effects of sea ice decline and hydrological cycle intensification have strengthened coupling between the ocean and the atmosphere (e.g., wind and ice drift stresses, solar radiation, and heat and moisture exchange), the bordering drainage basins (e.g., river discharge, sediment transport, and erosion), and terrestrial ecosystems (e.g., Arctic greening, dissolved and particulate carbon loading, and altered phenology of biotic components). External to the Arctic freshwater export acts as both a constraint to and a necessary ingredient for deep convection in the bordering subarctic gyres and thus affects the global thermohaline circulation. Geochemical fingerprints attained within the Arctic Ocean are likewise exported into the neighboring subarctic systems and beyond. Finally, we discuss observed and modeled functions and changes in this system on seasonal, annual, and decadal time scales and discuss mechanisms that link the marine system to atmospheric, terrestrial, and cryospheric systems.

  19. Radioactive equilibrium in ancient marine sediments

    Science.gov (United States)

    Breger, I.A.

    1955-01-01

    Radioactive equilibrium in eight marine sedimentary formations has been studied by means of direct determinations of uranium, radium and thorium. Alpha-particle counting has also been carried out in order to cross-calibrate thick-source counting techniques. The maximum deviation from radioactive equilibrium that has been noted is 11 per cent-indicating that there is probably equilibrium in all the formations analyzed. Thick-source alpha-particle counting by means of a proportional counter or an ionization chamber leads to high results when the samples contain less than about 10 p.p.m. of uranium. For samples having a higher content of uranium the results are in excellent agreement with each other and with those obtained by direct analytical techniques. The thorium contents that have been obtained correspond well to the average values reported in the literature. The uranium content of marine sediments may be appreciably higher than the average values that have been reported for sedimentary rocks. Data show that there is up to fourteen times the percentage of uranium as of thorium in the formations studied and that the percentage of thorium never exceeds that of uranium. While the proximity of a depositional environment to a land mass may influence the concentration of uranium in a marine sediment, this is not true with thorium. ?? 1955.

  20. Influence of Sea Ice on Arctic Marine Sulfur Biogeochemistry in the Community Climate System Model

    Energy Technology Data Exchange (ETDEWEB)

    Deal, Clara [Univ. of Alaska, Fairbanks, AL (United States); Jin, Meibing [Univ. of Alaska, Fairbanks, AL (United States)

    2013-06-30

    Global climate models (GCMs) have not effectively considered how responses of arctic marine ecosystems to a warming climate will influence the global climate system. A key response of arctic marine ecosystems that may substantially influence energy exchange in the Arctic is a change in dimethylsulfide (DMS) emissions, because DMS emissions influence cloud albedo. This response is closely tied to sea ice through its impacts on marine ecosystem carbon and sulfur cycling, and the ice-albedo feedback implicated in accelerated arctic warming. To reduce the uncertainty in predictions from coupled climate simulations, important model components of the climate system, such as feedbacks between arctic marine biogeochemistry and climate, need to be reasonably and realistically modeled. This research first involved model development to improve the representation of marine sulfur biogeochemistry simulations to understand/diagnose the control of sea-ice-related processes on the variability of DMS dynamics. This study will help build GCM predictions that quantify the relative current and possible future influences of arctic marine ecosystems on the global climate system. Our overall research objective was to improve arctic marine biogeochemistry in the Community Climate System Model (CCSM, now CESM). Working closely with the Climate Ocean Sea Ice Model (COSIM) team at Los Alamos National Laboratory (LANL), we added 1 sea-ice algae and arctic DMS production and related biogeochemistry to the global Parallel Ocean Program model (POP) coupled to the LANL sea ice model (CICE). Both CICE and POP are core components of CESM. Our specific research objectives were: 1) Develop a state-of-the-art ice-ocean DMS model for application in climate models, using observations to constrain the most crucial parameters; 2) Improve the global marine sulfur model used in CESM by including DMS biogeochemistry in the Arctic; and 3) Assess how sea ice influences DMS dynamics in the arctic marine

  1. Metabarcoding Marine Sediments: Preparation of Amplicon Libraries.

    Science.gov (United States)

    Fonseca, Vera G; Lallias, Delphine

    2016-01-01

    The accurate assessment of community composition and ultimately species identification is of utmost importance in any ecological and evolutionary study. Advances in sequencing technologies have allowed the unraveling of levels of biodiversity never imagined before when applied to large-scale environmental DNA studies (also termed metabarcoding/metagenetics/metasystematics/environmental barcoding). Here, we describe a detailed protocol to assess eukaryotic biodiversity in marine sediments, identifying key steps that should not be neglected when preparing Next-Generation Sequencing (NGS) amplicon libraries: DNA extraction, multiple PCR amplification of DNA barcode markers with index/ tag-primers, and final Illumina MiSeq sequencing library preparation. PMID:27460378

  2. Diagenetic regimes in Arctic Ocean sediments: Implications for sediment geochemistry and core correlation

    Science.gov (United States)

    Meinhardt, A.-K.; März, C.; Schuth, S.; Lettmann, K. A.; Schnetger, B.; Wolff, J.-O.; Brumsack, H.-J.

    2016-09-01

    Dark brown sediment layers are a potential stratigraphic tool in Quaternary Arctic Ocean sediments. They are rich in Mn, Fe, and trace metals scavenged from the water column and were most likely deposited during interglacial intervals. In this study, we combine sediment and pore water data from sediment cores taken in different parts of the Arctic Ocean to investigate the influence of early diagenetic processes on sediment geochemistry. In most studied cores, Mn, Co, and Mo are released into the pore waters from Mn oxide dissolution in deeper (>1.5 m) sediment layers. The relationship between sedimentary Mn, Co, and Mo contents in excess of the lithogenic background (elementxs) shows that Coxs/Moxs values are a diagnostic tool to distinguish between layers with diagenetic metal addition from the pore waters (Coxs/Moxs 10), and unaffected layers (Coxs/Moxs from 1 to 10). Steady-state calculations based on current pore water profiles reveal that in the studied cores, the diagenetic addition of these metals from the pore water pool alone is not sufficient to produce the sedimentary metal enrichments. However, it seems evident that dissolution of Mn oxides in the Mn reduction zone can permanently alter the primary geochemical signature of the dark brown layers. Therefore, pore water data and Coxs/Moxs values should be considered before core correlation when this correlation is solely based on Mn contents and dark sediment color. In contrast to the mostly non-lithogenic origin of Mn in the dark brown layers, sedimentary Fe consists of a large lithogenic (80%) and a small non-lithogenic fraction (20%). Our pore water data show that diagenetic Fe remobilization is not currently occurring in the sediment. The dominant Fe sources are coastal erosion and river input. Budget calculations show that Fe seems to be trapped in the modern Arctic Ocean and accumulates in shelf and basin sediments. The Fe isotopic signal δ56Fe of the solid phase is positive (∼0.2-0.3‰) in

  3. Biogeochemistry of pyrite and iron sulfide oxidation in marine sediments

    DEFF Research Database (Denmark)

    Schippers, A.; Jørgensen, BB

    2002-01-01

    Pyrite (FeS2) and iron monosulfide (FeS) play a central role in the sulfur and iron cycles of marine sediments, They may be buried in the sediment or oxidized by O-2 after transport by bioturbation to the sediment surface. FeS2 and FeS may also be oxidized within the anoxic sediment in which NO3-...

  4. Sediment Burial Intolerance of Marine Macroinvertebrates.

    Directory of Open Access Journals (Sweden)

    Vicki J Hendrick

    Full Text Available The marine environment contains suspended particulate matter which originates from natural and anthropogenic sources. Settlement of this material can leave benthic organisms susceptible to smothering, especially if burial is sudden i.e. following storms or activities such as dredging. Their survival will depend on their tolerance to, and their ability to escape from burial. Here we present data from a multi-factorial experiment measuring burial responses incorporating duration, sediment fraction and depth. Six macroinvertebrates commonly found in sediment rich environments were selected for their commercial and/or conservation importance. Assessments revealed that the brittle star (Ophiura ophiura, the queen scallop (Aequipecten opercularis and the sea squirt (Ciona intestinalis were all highly intolerant to burial whilst the green urchin (Psammichinus miliaris and the anemone (Sagartiogeton laceratus, showed intermediate and low intolerance respectively, to burial. The least intolerant, with very high survival was the Ross worm (Sabellaria spinulosa. With the exception of C. intestinalis, increasing duration and depth of burial with finer sediment fractions resulted in increased mortality for all species assessed. For C. intestinalis depth of burial and sediment fraction were found to be inconsequential since there was complete mortality of all specimens buried for more than one day. When burial emergence was assessed O. ophiura emerged most frequently, followed by P. miliaris. The former emerged most frequently from the medium and fine sediments whereas P. miliaris emerged more frequently from coarse sediment. Both A. opercularis and S. laceratus showed similar emergence responses over time, with A. opercularis emerging more frequently under coarse sediments. The frequency of emergence of S. laceratus increased with progressively finer sediment and C. intestinalis did not emerge from burial irrespective of sediment fraction or depth. Finally

  5. Contaminants, benthic communities, and bioturbation: potential for PAH mobilisation in Arctic sediments

    Energy Technology Data Exchange (ETDEWEB)

    Konovalov, D.; Renaud, P.E.; Berge, J.; Voronkov, A.Y.; Cochrane, S.K.J. [Polar Environmental Center, Tromso (Norway)

    2010-07-01

    Marine benthic fauna and biological mixing were studied in relation to sediment organic enrichment and polyaromatic hydrocarbons (PAHs) in bottom sediments of Svalbard. We investigated how organic enrichment may affect the fate and chemical composition of deposited contaminants by impacting biological reworking by faunal communities. Samples were collected near active coal mines at Barentsburg and at the mouth of Groenfjord. PAH sources in both areas were coal particles and pyrolytic compounds from coal-driven power stations. The results from a bioturbation experiment were consistent with the hypothesis that fauna enhance the vertical transport of PAHs within the sediment. Faunal community composition was similar at the two sites, with polychaete worms comprising 85% of the fauna. Abundances and taxon richness were eight and ten times higher in the organically enriched sediments near Barentsburg, and total PAH concentrations were up to three times higher in Barentsburg. Unlike expectations derived from models developed for temperate regions, organic enrichment in oligotrophic areas, such as this Arctic site, enhanced the biomass and bioturbation potential of benthic communities. Hence, new insights into the relationships among enrichment, benthic communities and the fate of contaminants must be considered in management and regulatory efforts in these areas.

  6. Nonlinear acoustics of water-saturated marine sediments

    DEFF Research Database (Denmark)

    Jensen, Leif Bjørnø

    1976-01-01

    Interest in the acoustic qualities of water-saturated marine sediments has increased considerably during recent years. The use of sources of high-intensity sound in oil propsecting, in geophysical and geological studies of bottom and subbottom materials and profiles and recently in marine...... archaeology has emphasized the need of information about the nonlinear acoustic qualities of water-saturated marine sediments. While the acoustic experiments and theoretical investigations hitherto performed have concentrated on a determination of the linear acoustic qualities of water-saturated marine...... sediments, their parameters of nonlinear acoustics are still unexplored. The strong absorption, increasing about linearly with frequency, found in most marine sediments and the occurrence of velocity dispersion by some marine sediments restrict the number of nonlinear acoustic test methods traditionally...

  7. Freshwater discharges drive high levels of methylmercury in Arctic marine biota.

    Science.gov (United States)

    Schartup, Amina T; Balcom, Prentiss H; Soerensen, Anne L; Gosnell, Kathleen J; Calder, Ryan S D; Mason, Robert P; Sunderland, Elsie M

    2015-09-22

    Elevated levels of neurotoxic methylmercury in Arctic food-webs pose health risks for indigenous populations that consume large quantities of marine mammals and fish. Estuaries provide critical hunting and fishing territory for these populations, and, until recently, benthic sediment was thought to be the main methylmercury source for coastal fish. New hydroelectric developments are being proposed in many northern ecosystems, and the ecological impacts of this industry relative to accelerating climate changes are poorly characterized. Here we evaluate the competing impacts of climate-driven changes in northern ecosystems and reservoir flooding on methylmercury production and bioaccumulation through a case study of a stratified sub-Arctic estuarine fjord in Labrador, Canada. Methylmercury bioaccumulation in zooplankton is higher than in midlatitude ecosystems. Direct measurements and modeling show that currently the largest methylmercury source is production in oxic surface seawater. Water-column methylation is highest in stratified surface waters near the river mouth because of the stimulating effects of terrestrial organic matter on methylating microbes. We attribute enhanced biomagnification in plankton to a thin layer of marine snow widely observed in stratified systems that concentrates microbial methylation and multiple trophic levels of zooplankton in a vertically restricted zone. Large freshwater inputs and the extensive Arctic Ocean continental shelf mean these processes are likely widespread and will be enhanced by future increases in water-column stratification, exacerbating high biological methylmercury concentrations. Soil flooding experiments indicate that near-term changes expected from reservoir creation will increase methylmercury inputs to the estuary by 25-200%, overwhelming climate-driven changes over the next decade.

  8. Composition index of n-alkanes and paleoenvironmental study in sediments of the Arctic

    Institute of Scientific and Technical Information of China (English)

    Lu Bing; Zhou Huaiyang; Wang Zipan; Lu Douding

    2001-01-01

    This paper reports different concentration patterns of n-alkanes distribution in the sediments from the Chukchi Sea, the Bering Sea in the Arctic. Factor statistical analysis method is used for studying the source of n-alkanes and paleoenviroment. The result shows that n-alkanes is in the range of nC15~nC33 and n-alkane distribution patterns are characterized by two modes. The first mode belongs to the higher molecular with MH being nC25~ nC27, CPI> 1 and with remarkable odd-even dominance.They are of terrigenous plant origin. The second one belongs to lower carbon range with MH being nC17 ~nC20, CPI> 1 and with indistinct odd-even dominance. Therefore they are contributed by marine biological inputs. The contribution of land origin is larger than that of marine source. Pr/Ph is lower than 1 in the investigated area, which indicates the depositional environment of reducing reaction with lower oxygen. The result of factor analysis has good agreement with composition characteristics of n-alkanes in the sediment.

  9. Biogeographic patterns of bacterial microdiversity in Arctic deep-sea sediments (Hausgarten, Fram Strait

    Directory of Open Access Journals (Sweden)

    Pier Luigi eButtigieg

    2015-01-01

    Full Text Available Marine bacteria colonising deep-sea sediments beneath the Arctic ocean, a rapidly changing ecosystem, have been shown to exhibit significant biogeographic patterns along transects spanning tens of kilometres and across water depths reaching several thousands of metres (Jacob et al., 2013. Jacob et al. adopted what has become a classical view of microbial diversity based on operational taxonomic units clustered at the 97% sequence identity level of the 16S rRNA gene and observed a very large microbial community replacement at the Hausgarten Long-Term Ecological Research station (Eastern Fram Strait. Here, we revisited these data using the oligotyping approach with the aims of obtaining new insights into ecological and biogeographic patterns associated with bacterial microdiversity in marine sediments and of assessing the level of concordance of these insights with previously obtained results. Variation in oligotype dispersal range, relative abundance, co-occurrence, and taxonomic identity were related to environmental parameters such as water depth, biomass, and sedimentary pigment concentration. This study assesses ecological implications of the new microdiversity-based technique using a well-characterised dataset of high relevance for global change biology.

  10. Plutonium in the Arctic Marine Environment — A Short Review

    Directory of Open Access Journals (Sweden)

    Lindis Skipperud

    2004-01-01

    Full Text Available Anthropogenic plutonium has been introduced into the environment over the past 50 years as the result of the detonation of nuclear weapons and operational releases from the nuclear industry. In the Arctic environment, the main source of plutonium is from atmospheric weapons testing, which has resulted in a relatively uniform, underlying global distribution of plutonium. Previous studies of plutonium in the Kara Sea have shown that, at certain sites, other releases have given rise to enhanced local concentrations. Since different plutonium sources are characterised by distinctive plutonium-isotope ratios, evidence of a localised influence can be supported by clear perturbations in the plutonium-isotope ratio fingerprints as compared to the known ratio in global fallout. In Kara Sea sites, such perturbations have been observed as a result of underwater weapons tests at Chernaya Bay, dumped radioactive waste in Novaya Zemlya, and terrestrial runoff from the Ob and Yenisey Rivers. Measurement of the plutonium-isotope ratios offers both a means of identifying the origin of radionuclide contamination and the influence of the various nuclear installations on inputs to the Arctic, as well as a potential method for following the movement of water and sediment loads in the rivers.

  11. 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 (depressions and in central part of the sea, which is quite wide from both places of original sedimentation and run off sources [2]. Thus, the interrelation

  12. Characterization of marine near-surface sediments by electromagnetic profiling

    OpenAIRE

    Müller, Hendrik

    2010-01-01

    This thesis investigates the theory, develops the technology and demonstrates the applicabilities for synchronous in-situ mapping of the magnetic and electric signatures of marine near-surface sediments. A marine electromagnetic profiler has been developed for coastal and shelf operations in 5 to 500 m water depths. The system was designed to resolve subtle and gradual variations in silt and clay content, porosity and diagenesis state of marine sediments at a sub-meter scale. An electromagnet...

  13. Shifts in Identity and Activity of Methanotrophs in Arctic Lake Sediments in Response to Temperature Changes

    OpenAIRE

    He, Ruo; Wooller, Matthew J; Pohlman, John W.; Quensen, John; Tiedje, James M.; Leigh, Mary Beth

    2012-01-01

    Methane (CH4) flux to the atmosphere is mitigated via microbial CH4 oxidation in sediments and water. As arctic temperatures increase, understanding the effects of temperature on the activity and identity of methanotrophs in arctic lake sediments is important to predicting future CH4 emissions. We used DNA-based stable-isotope probing (SIP), quantitative PCR (Q-PCR), and pyrosequencing analyses to identify and characterize methanotrophic communities active at a range of temperatures (4°C, 10°...

  14. Untargeted Screening and Distribution of Organo-Iodine Compounds in Sediments from Lake Michigan and the Arctic Ocean.

    Science.gov (United States)

    Peng, Hui; Chen, Chunli; Cantin, Jenna; Saunders, David M V; Sun, Jianxian; Tang, Song; Codling, Garry; Hecker, Markus; Wiseman, Steve; Jones, Paul D; Li, An; Rockne, Karl J; Sturchio, Neil C; Cai, Minghong; Giesy, John P

    2016-09-20

    The majority of halogenated organic compounds present in the environment remain unidentified. To address this data gap, we recently developed an untargeted method (data-independent precursor isolation and characteristic fragment; DIPIC-Frag) for identification of unknown organo-bromine compounds. In this study, the method was adapted to enable untargeted screening of natural and synthetic organo-iodine compounds (NSOICs) in sediments. A total of 4,238 NSOIC peaks were detected in sediments from Lake Michigan. Precursor ions and formulas were determined for 2,991 (71%) of the NSOIC peaks. These compounds exhibited variations in abundances (<10(3) to ∼10(7)), m/z values (206.9304-996.9474), retention times (1.0-29.7 min), and number of iodine atoms (1-4). Hierarchical cluster analysis showed that sediments in closer proximity exhibited similar profiles of NSOICs. NSOICs were screened in 10 samples of sediment from the Arctic Ocean to compare the profiles of NSOICs between freshwater and marine sediments. A total of 3,168 NSOIC peaks were detected, and profiles of NSOICs in marine sediments were clearly distinct from Lake Michigan. The coexistence of brominated and iodinated analogues indicated that some NSOICs are of natural origin. Different ratios of abundances of iodinated compounds to brominated analogues were observed and proposed as a marker to distinguish sources of NSOICs.

  15. Arctic marine climate of the early nineteenth century

    Directory of Open Access Journals (Sweden)

    P. Brohan

    2010-02-01

    Full Text Available The climate of the early nineteenth century is likely to have been significantly cooler than that of today, as it was a period of low solar activity (the Dalton minimum and followed a series of large volcanic eruptions. Proxy reconstructions of the temperature of the period do not agree well on the size of the temperature change, so other observational records from the period are particularly valuable. Weather observations have been extracted from the reports of the noted whaling captain William Scoresby Jr., and from the records of a series of Royal Navy expeditions to the Arctic, preserved in the UK National Archives. They demonstrate that marine climate in 1810–25 was marked by consistently cold summers, with abundant sea-ice. But although the period was significantly colder than the modern average, there was a lot of variability: in the Greenland Sea the summers following the Tambora eruption (1816 and 1817 were noticeably warmer, and had lower sea-ice coverage, than the years immediately preceding them; and the sea-ice coverage in Lancaster Sound in 1819 and 1820 was low even by modern standards.

  16. Arctic marine climate of the early nineteenth century

    Directory of Open Access Journals (Sweden)

    P. Brohan

    2010-05-01

    Full Text Available The climate of the early nineteenth century is likely to have been significantly cooler than that of today, as it was a period of low solar activity (the Dalton minimum and followed a series of large volcanic eruptions. Proxy reconstructions of the temperature of the period do not agree well on the size of the temperature change, so other observational records from the period are particularly valuable. Weather observations have been extracted from the reports of the noted whaling captain William Scoresby Jr., and from the records of a series of Royal Navy expeditions to the Arctic, preserved in the UK National Archives. They demonstrate that marine climate in 1810–1825 was marked by consistently cold summers, with abundant sea-ice. But although the period was significantly colder than the modern average, there was considerable variability: in the Greenland Sea the summers following the Tambora eruption (1816 and 1817 were noticeably warmer, and had less sea-ice coverage, than the years immediately preceding them; and the sea-ice coverage in Lancaster Sound in 1819 and 1820 was low even by modern standards.

  17. Organic carbon and nitrogen isotopes in surface sediments from the western Arctic Ocean and their implications for sedimentary environments

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhihua; SHI Xuefa; CAI Deling; HAN Yibing; YANG Zuosheng

    2006-01-01

    Surface sediments from the Chukchi Sea and adjacent arctic deep sea were investigated for organic carbon and nitrogen isotopes (in δ13Corg and δ15Norg) as well as biogenic silica (BSiO2). δ13Corg and δ15Norg values of surface sediments in the study area fall between the end-member values of marine and terrestrial organic matter from the surrounding lands and seas, their variations reflect the changes of marine productivity and terrestrial supply in the study area. BSiO2 shows a similar distribution pattern with δ13Corg and δ15Norg, and can be used as an indicator of marine productivity. In the central-west Chukchi Sea and the Chukchi Rise, sediments have higher δ13Corg, δ15Norg and BSiO2 values, indicating the region has high marine productivity influenced by the nutrient-rich branches of the Pacific waters. In the coastal zone off northwestern Alaska, δ13Corg and δ15Norg values become lighter, indicating a weakening marine productivity and an increasing terrigenous supply due to the effects of the least nutrient-rich branch of the Pacific waters. In the north and the northeast of the study area (including the Chukchi Plateau, the Canada Basin and the Beaufort shelf), δ13Corg, δ15Norg and BSiO2 have the lowest values, and the terrigenous organic matter becomes dominant in surface sediments because this region has the longest ice-covered duration, the least nutrient-rich seawater and the increasing supply of terrestrial materials from the Mackenzie River and the northern Alaska under the action of the clockwise Beaufort gyre. Because the subarctic Pacific waters are continuously discharged into the central basin of the Arctic Ocean through the study area, the nutrient pool in the Chukchi Sea can be considered as a typical open system, the ratio of δ15N to BSiO2 content show some tracers that the level of nutrient utilization is contrary to nutrient supply and marine productivity formed in seawater.

  18. Untargeted Screening and Distribution of Organo-Iodine Compounds in Sediments from Lake Michigan and the Arctic Ocean.

    Science.gov (United States)

    Peng, Hui; Chen, Chunli; Cantin, Jenna; Saunders, David M V; Sun, Jianxian; Tang, Song; Codling, Garry; Hecker, Markus; Wiseman, Steve; Jones, Paul D; Li, An; Rockne, Karl J; Sturchio, Neil C; Cai, Minghong; Giesy, John P

    2016-09-20

    The majority of halogenated organic compounds present in the environment remain unidentified. To address this data gap, we recently developed an untargeted method (data-independent precursor isolation and characteristic fragment; DIPIC-Frag) for identification of unknown organo-bromine compounds. In this study, the method was adapted to enable untargeted screening of natural and synthetic organo-iodine compounds (NSOICs) in sediments. A total of 4,238 NSOIC peaks were detected in sediments from Lake Michigan. Precursor ions and formulas were determined for 2,991 (71%) of the NSOIC peaks. These compounds exhibited variations in abundances (Arctic Ocean to compare the profiles of NSOICs between freshwater and marine sediments. A total of 3,168 NSOIC peaks were detected, and profiles of NSOICs in marine sediments were clearly distinct from Lake Michigan. The coexistence of brominated and iodinated analogues indicated that some NSOICs are of natural origin. Different ratios of abundances of iodinated compounds to brominated analogues were observed and proposed as a marker to distinguish sources of NSOICs. PMID:27611727

  19. Accelerated delivery of polychlorinated biphenyls (PCBs) in recent sediments near a large seabird colony in Arctic Canada

    International Nuclear Information System (INIS)

    Polychlorinated biphenyls (PCBs) were measured in sediment cores from ponds located near a large seabird colony at Cape Vera, Devon Island, Arctic Canada. Surface sediment PCB concentrations were ∼5x greater in seabird-affected sites relative to a nearby control pond and were correlated with independent indicators of seabird activity including, sedimentary δ15N and lakewater chlorophyll a and cadmium concentrations. PCB fluxes were amongst the highest recorded from the High Arctic, ranging from 290 to 2400 ng m-2 yr-1. Despite a widespread ban of PCBs in the mid-1970s, PCB accumulation rates in our cores increased, with the highest values recorded in the most recent sediments. Possible mechanisms for the recent PCB increases include a vertical flux step driven by seabird-delivered nutrients and/or delayed loading of PCBs from the catchment into the ponds. The high PCB levels recorded in the seabird-affected sites suggest that seabird colonies are exposing coastal ecosystems to elevated levels of contaminants. - Seabird activity accelerates the delivery of PCBs from marine to terrestrial ecosystems.

  20. Preservation potential of ancient plankton DNA in Pleistocene marine sediments

    NARCIS (Netherlands)

    Boere, A.C.; Rijpstra, W.I.C.; de Lange, G.J.; Sinninghe Damsté, J.S.; Coolen, M.J.L.

    2011-01-01

    Recent studies have shown that ancient plankton DNA can be recovered from Holocene lacustrine and marine sediments, including from species that do not leave diagnostic microscopic fossils in the sediment record. Therefore, the analysis of this so-called fossil plankton DNA is a promising approach fo

  1. Algal and archaeal polyisoprenoids in a recent marine sediment

    DEFF Research Database (Denmark)

    Bian, Liangqiao; Hinrichs, Kai-Uwe; Xie, Tianmin;

    2001-01-01

    Analyses of C-13 contents of individual organic molecules in a marine sediment show that crocetane, 2,6,11,15-tetramethylhexadecane, an isomer of phytane, is produced by microorganisms that use methane as their main source of carbon. The sediments lie at a water depth of 68 m in the Kattegat...

  2. Arctic marine gravity and bathymetry from 3 years of Cryosat-2 SAR altimetry (DTU13 Gravity)

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Stenseng, Lars; Knudsen, Per;

    The accuracy of the Arctic marine gravity field has for many been severely limited by the availability and accuracy of altimeter data in the Arctic Ocean. Until recently only ERS-1 provided non-repeat (0.9 year) geodetic mission altimetry in the Arctic Ocean and only up to 82N. With the launch...... of Cryosat-2 three years ago a new source of high quality altimetric data has become available. The Cryosat-2 delay Doppler altimeter offers a factor of 20 improvements in along track resolution, an along-track footprint length that does not vary with wave height (sea state) and at least a factor of two......1 SAR altimetry in the Arctic Ocean for gravity field determination. Extensive testing, interpretation and improvement of methods to handles the new class of data has been investigated and the first result from a new Arctic Ocean wide gravity field will be presented as well as initial test...

  3. Correlating microbial community profiles with geochemical data in highly stratified sediments from the Arctic Mid-Ocean Ridge.

    Science.gov (United States)

    Jorgensen, Steffen Leth; Hannisdal, Bjarte; Lanzén, Anders; Baumberger, Tamara; Flesland, Kristin; Fonseca, Rita; Ovreås, Lise; Steen, Ida H; Thorseth, Ingunn H; Pedersen, Rolf B; Schleper, Christa

    2012-10-16

    Microbial communities and their associated metabolic activity in marine sediments have a profound impact on global biogeochemical cycles. Their composition and structure are attributed to geochemical and physical factors, but finding direct correlations has remained a challenge. Here we show a significant statistical relationship between variation in geochemical composition and prokaryotic community structure within deep-sea sediments. We obtained comprehensive geochemical data from two gravity cores near the hydrothermal vent field Loki's Castle at the Arctic Mid-Ocean Ridge, in the Norwegian-Greenland Sea. Geochemical properties in the rift valley sediments exhibited strong centimeter-scale stratigraphic variability. Microbial populations were profiled by pyrosequencing from 15 sediment horizons (59,364 16S rRNA gene tags), quantitatively assessed by qPCR, and phylogenetically analyzed. Although the same taxa were generally present in all samples, their relative abundances varied substantially among horizons and fluctuated between Bacteria- and Archaea-dominated communities. By independently summarizing covariance structures of the relative abundance data and geochemical data, using principal components analysis, we found a significant correlation between changes in geochemical composition and changes in community structure. Differences in organic carbon and mineralogy shaped the relative abundance of microbial taxa. We used correlations to build hypotheses about energy metabolisms, particularly of the Deep Sea Archaeal Group, specific Deltaproteobacteria, and sediment lineages of potentially anaerobic Marine Group I Archaea. We demonstrate that total prokaryotic community structure can be directly correlated to geochemistry within these sediments, thus enhancing our understanding of biogeochemical cycling and our ability to predict metabolisms of uncultured microbes in deep-sea sediments.

  4. Mineralogical study of surface sediments in the western Arctic Ocean and their implications for material sources

    Institute of Scientific and Technical Information of China (English)

    DONG Linsen; SHI Xuefa; LIU Yanguang; FANG Xisheng; CHEN Zhihua; WANG Chunjuan; ZOU Jianjun; HUANG Yuanhui

    2014-01-01

    Mineralogical analysis was performed on bulk sediments of 79 surface samples using X-ray diffraction. The analytical results, combined with data on ocean currents and the regional geological background, were used to investigate the mineral sources. Mineral assemblages in sediments and their distribution in the study area indicate that the material sources are complex. (1) Feldspar is abundant in the sediments of the middle Chukchi Sea near the Bering Strait, originating from sediments in the Anadyr River carried by the Anadyr Current. Sediments deposited on the western side of the Chukchi Sea are rich in feldspar. Compared with other areas, sediments in this region are rich in hornblende transported from volcanic and sedimentary rocks in Siberia by the Anadyr Stream and the Siberian Coastal Current. Sediments in the eastern Chukchi Sea are rich in quartz sourced from sediments of the Yukon and Kuskokwim rivers carried by the Alaska Coastal Current. Sediments in the northern Chukchi Sea are rich in quartz and carbonates from the Mackenzie River sediments. (2) Sediments of the southern and central Canada Basin contain little calcite and dolomite, mainly due to the small impact of the Beaufort Gyre carrying carbonates from the Canadian Arctic Islands. Compared with other areas, the mica content in the region is high, implying that the Laptev Sea is the main sediment source for the southern and central Canada Basin. In the other deep sea areas, calcite and dolomite levels are high caused by the input of large amounts of sediment carried by the Beaufort Gyre from the Canadian Arctic Islands (Banks and Victoria). The Siberian Laptev Sea also provides small amounts of sediment for this region. Furthermore, the Atlantic mid-water contributes some fine-grained material to the entire deep western Arctic Ocean.

  5. Bioavailability of sediment-bound contaminants to marine organisms

    Energy Technology Data Exchange (ETDEWEB)

    Brown, B. [Battelle/Marine Sciences Lab., Sequim, WA (United States)]|[Colby Coll., Waterville, ME (United States); Neff, J. [Battelle/Marine Sciences Lab., Sequim, WA (United States)]|[Battelle Ocean Sciences, Duxbury, MA (United States)

    1993-09-01

    The bioavailability of sediment-bound contaminants to marine organisms indicates that there exists a potential for transfer of these contaminants through marine food webs to commercial fisheries products consumed by humans. However, there has been relatively little effort to combine and synthesize data on chemical/biological interactions between benthic animals and seagrasses and the sediments in which they reside on the one hand, and on the chemistry of bioaccumulation on the other. This report provides a conceptual basis for an approach to bioavailability and biomagnification of sediment-bound contaminants that reviews biological and chemical approaches.

  6. Impact of CryoSat-2 for marine gravity field - globally and in the Arctic Ocean

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Stenseng, Lars; Knudsen, Per;

    days repeat offered by CryoSat-2 provides denser coverage than older geodetic mission data set like ERS-1. Thirdly, the 92 degree inclination of CryoSat-2 is designed to map more of the Arctic Ocean than previous altimetric satellites. Finally, CryoSat-2 is able to operate in two new modes (SAR and SAR...... GDR data, NOAA LRM data, but also Level1b (LRM, SAR and SAR-in waveforms) data have been analyzed. A suite of eight different empirical retrackers have been developed and investigated for their ability to predict marine gravity in the Arctic Ocean. The impact of the various improvement offered by Cryo......Sat-2 in comparison with conventional satellite altimetry have been studied and quantified both globally but particularly for the Arctic Ocean using a large number of marine and airborne surveys providing “ground truth” marine gravity....

  7. Factors Effecting Adsorption of 137 Cs in Marine Sediment Samples in Marine Sediment Samples from the Upper Gulf of Thailand

    International Nuclear Information System (INIS)

    Contamination of 137Cs in sediment is a far more serious problem than in water because sediment is a main transport factor of 137Cs to the aquatic environmental. Most of 137Cs in water could be accumulated in sediment which has direct effect to benthos. This study focused on factors effecting the adsorption of 137Cs in marine sediment samples collected from four different estuary sites to assess the transfer direction of 137Cs from water to sediment that the study method by treat 137Cs into seawater and mixed with different sediment samples for 4 days. The result indicated that properties of marine sediment (cation exchange capacity (CEC), organic matter, clay content, texture, type of clay mineral and size of soil particle) had effects on 137Cs adsorption. CEC and clay content correlated positively with the accumulation of 137Cs in the marine sediment samples. On the other hand, organic matter in sediment correlated negatively with the accumulation of 137Cs in samples. The study of environmental effects (pH and potassium) found that the 137Cs adsorption decreased when concentration of potassium increased. The pH effect is still unclear in this study because the differentiation of pH levels (6, 7, 8.3) did not have effects on 137Cs adsorption in the samples.

  8. Biodegradation of petroleum in marine seep sediments

    OpenAIRE

    Mishra, Sonakshi

    2016-01-01

    This study presented for the first time the use of intact sediment cores in a continuous sediment-oil-flow-through (SOFT) system for investigating the degradation of petroleum under a simulated petroleum seepage.The biogeochemical response of sediments from hydrocarbon adapted sites like the Caspian Sea, North Alex Mud Volcano in the Eastern Mediterranean, the Santa Barbara Channel and non-adapted site like the Eckernfoerde Bay in the Baltic Sea to petroleum seepage was investigated and compa...

  9. Sulfate reduction and methanogenesis in marine sediments

    Science.gov (United States)

    Oremland, R. S.; Taylor, B. F.

    1978-01-01

    Methanogenesis and sulfate-reduction were followed in laboratory incubations of sediments taken from tropical seagrass beds. Methanogenesis and sulfate-reduction occurred simultaneously in sediments incubated under N2, thereby indicating that the two processes are not mutually exclusive. Sediments incubated under an atmosphere of H2 developed negative pressures due to the oxidation of H2 by sulfate-respiring bacteria. H2 also stimulated methanogenesis, but methanogenic bacteria could not compete for H2 with the sulfate-respiring bacteria.

  10. Methane-derived carbon flow through microbial communities in arctic lake sediments.

    Science.gov (United States)

    He, Ruo; Wooller, Matthew J; Pohlman, John W; Tiedje, James M; Leigh, Mary Beth

    2015-09-01

    Aerobic methane (CH4 ) oxidation mitigates CH4 release and is a significant pathway for carbon and energy flow into aquatic food webs. Arctic lakes are responsible for an increasing proportion of global CH4 emissions, but CH4 assimilation into the aquatic food web in arctic lakes is poorly understood. Using stable isotope probing (SIP) based on phospholipid fatty acids (PLFA-SIP) and DNA (DNA-SIP), we tracked carbon flow quantitatively from CH4 into sediment microorganisms from an arctic lake with an active CH4 seepage. When 0.025 mmol CH4 g(-1) wet sediment was oxidized, approximately 15.8-32.8% of the CH4 -derived carbon had been incorporated into microorganisms. This CH4 -derived carbon equated to up to 5.7% of total primary production estimates for Alaskan arctic lakes. Type I methanotrophs, including Methylomonas, Methylobacter and unclassified Methylococcaceae, were most active at CH4 oxidation in this arctic lake. With increasing distance from the active CH4 seepage, a greater diversity of bacteria incorporated CH4 -derived carbon. Actinomycetes were the most quantitatively important microorganisms involved in secondary feeding on CH4 -derived carbon. These results showed that CH4 flows through methanotrophs into the broader microbial community and that type I methanotrophs, methylotrophs and actinomycetes are important organisms involved in using CH4 -derived carbon in arctic freshwater ecosystems. PMID:25581131

  11. Seasonal variation in accumulation of persistent organic pollutants in an Arctic marine benthic food web.

    Science.gov (United States)

    Evenset, A; Hallanger, I G; Tessmann, M; Warner, N; Ruus, A; Borgå, K; Gabrielsen, G W; Christensen, G; Renaud, P E

    2016-01-15

    The aim of the present study was to investigate seasonal variation in persistent organic pollutant (POP) concentrations, as well as food-web biomagnification, in an Arctic, benthic marine community. Macrozoobenthos, demersal fish and common eiders were collected both inside and outside of Kongsfjorden, Svalbard, during May, July and October 2007. The samples were analysed for a selection of legacy chlorinated POPs. Overall, low levels of POPs were measured in all samples. Although POP levels and accumulation patterns showed some seasonal variation, the magnitude and direction of change was not consistent among species. Overall, seasonality in bioaccumulation in benthic biota was less pronounced than in the pelagic system in Kongsfjorden. In addition, the results indicate that δ(15)N is not a good predictor for POP-levels in benthic food chains. Other factors, such as feeding strategy (omnivory, necrophagy versus herbivory), degree of contact with the sediment, and a high dependence on particulate organic matter (POM), with low POP-levels and high δ(15)N-values (due to bacterial isotope enrichment), seem to govern the uptake of the different POPs and result in loads deviating from what would be expected consulting the trophic position alone. PMID:26519572

  12. Foreword to the thematic cluster: the Arctic in Rapid Transition—marine ecosystems

    Directory of Open Access Journals (Sweden)

    Monika Kędra

    2015-12-01

    Full Text Available The Arctic is warming and losing sea ice. Happening at a much faster rate than previously expected, these changes are causing multiple ecosystem feedbacks in the Arctic Ocean. The Arctic in Rapid Transition (ART initiative was developed by early-career scientists as an integrative, international, multidisciplinary, long-term pan-Arctic network to study changes and feedbacks among the physical and biogeochemical components of the Arctic Ocean and their ultimate impacts on biological productivity on different timescales. In 2012, ART jointly organized with the Association of Polar Early Career Scientists their second science workshop—Overcoming Challenges of Observation to Model Integration in Marine Ecosystem Response to Sea Ice Transitions—at the Institute of Oceanology, Polish Academy of Sciences, in Sopot. This workshop aimed to identify linkages and feedbacks between atmosphere–ice–ocean forcing and biogeochemical processes, which are critical for ecosystem function, land–ocean interactions and productive capacity of the Arctic Ocean. This special thematic cluster of Polar Research brings together seven papers that grew out of workgroup discussions. Papers examine the climate change impacts on various ecosystem elements, providing important insights on the marine ecological and biogeochemical processes on various timescales. They also highlight priority areas for future research.

  13. Measuring biogenic silica in marine sediments and suspended matter

    Science.gov (United States)

    DeMaster, David J.

    Measuring the biogenic silica content of marine sediments and suspended matter is essential for a variety of geochemical, biological, and sedimentological studies. Biota forming siliceous skeletal material account for as much as one third of the primary productivity in the ocean [Lisitzin, 1972] and a significant portion (2 to 70% by weight) of open-ocean sediments. Biogenic silica measurements reveal important information concerning the bulk chemistry of suspended material or sediment and are essential in any type of silica flux study in the water column or seabed. Analyses of this biogenic phase in marine plankton are useful in characterizing the basic types of biota present and in comparing the distributions of particulate and dissolved silicate when evaluating nutrient dynamics [Nelson and Smith, 1986]. In the marine environment, diatoms, radiolaria, sponges, and silicoflagellates are the common types of siliceous biota.

  14. Microbial bioavailability regulates organic matter preservation in marine sediments

    Directory of Open Access Journals (Sweden)

    K. A. Koho

    2012-09-01

    Full Text Available Burial of organic matter (OM plays an important role in marine sediments, linking the short-term, biological carbon cycle with the long-term, geological subsurface cycle. It is well established that low-oxygen conditions promote organic carbon burial in marine sediments. However, the mechanism remains enigmatic. Here we report biochemical quality, microbial degradability, OM preservation and accumulation along an oxygen gradient in the Indian Ocean. Our results show that more OM, and of biochemically higher quality, accumulates under low oxygen conditions. Nevertheless, microbial degradability does not correlate with the biochemical quality of OM. This decoupling of OM biochemical quality and microbial degradability, or bioavailability, violates the ruling paradigm that higher quality implies higher microbial processing. The inhibition of bacterial OM remineralisation may play an important role in the burial of organic matter in marine sediments and formation of oil source rocks.

  15. Late Quaternary stratigraphy and sedimentation patterns in the western Arctic Ocean

    Science.gov (United States)

    Polyak, L.; Bischof, J.; Ortiz, J.D.; Darby, D.A.; Channell, J.E.T.; Xuan, C.; Kaufman, D.S.; Lovlie, R.; Schneider, D.A.; Eberl, D.D.; Adler, R.E.; Council, E.A.

    2009-01-01

    Sediment cores from the western Arctic Ocean obtained on the 2005 HOTRAX and some earlier expeditions have been analyzed to develop a stratigraphic correlation from the Alaskan Chukchi margin to the Northwind and Mendeleev-Alpha ridges. The correlation was primarily based on terrigenous sediment composition that is not affected by diagenetic processes as strongly as the biogenic component, and paleomagnetic inclination records. Chronostratigraphic control was provided by 14C dating and amino-acid racemization ages, as well as correlation to earlier established Arctic Ocean stratigraphies. Distribution of sedimentary units across the western Arctic indicates that sedimentation rates decrease from tens of centimeters per kyr on the Alaskan margin to a few centimeters on the southern ends of Northwind and Mendeleev ridges and just a few millimeters on the ridges in the interior of the Amerasia basin. This sedimentation pattern suggests that Late Quaternary sediment transport and deposition, except for turbidites at the basin bottom, were generally controlled by ice concentration (and thus melt-out rate) and transportation distance from sources, with local variances related to subsurface currents. In the long term, most sediment was probably delivered to the core sites by icebergs during glacial periods, with a significant contribution from sea ice. During glacial maxima very fine-grained sediment was deposited with sedimentation rates greatly reduced away from the margins to a hiatus of several kyr duration as shown for the Last Glacial Maximum. This sedimentary environment was possibly related to a very solid ice cover and reduced melt-out over a large part of the western Arctic Ocean.

  16. Marine Mammals and Climate Change in the Pacific Arctic: Impacts & Resilience

    Science.gov (United States)

    Moore, S. E.

    2014-12-01

    Extreme reductions in Arctic sea ice extent and thickness have become a hallmark of climate change, but impacts to the marine ecosystem are poorly understood. As top predators, marine mammals must adapt to biological responses to physical forcing and thereby become sentinels to ecosystem variability and reorganization. Recent sea ice retreats have influenced the ecology of marine mammals in the Pacific Arctic sector. Walruses now often haul out by the thousands along the NW Alaska coast in late summer, and reports of harbor porpoise, humpback, fin and minke whales in the Chukchi Sea demonstrate that these temperate species routinely occur there. In 2010, satellite tagged bowhead whales from Atlantic and Pacific populations met in the Northwest Passage, an overlap thought precluded by sea ice since the Holocene. To forage effectively, baleen whales must target dense patches of zooplankton and small fishes. In the Pacific Arctic, bowhead and gray whales appear to be responding to enhanced prey availability delivered both by new production and advection pathways. Two programs, the Distributed Biological Observatory (DBO) and the Synthesis of Arctic Research (SOAR), include tracking of marine mammal and prey species' responses to ecosystem shifts associated with sea ice loss. Both programs provide an integrated-ecosystem baseline in support of the development of a web-based Marine Mammal Health Map, envisioned as a component of the U.S. Integrated Ocean Observing System (IOOS). An overarching goal is to identify ecological patterns for marine mammals in the 'new' Arctic, as a foundation for integrative research, local response and adaptive management.

  17. Identification of functionally active aerobic methanotrophs in sediments from an arctic lake using stable isotope probing

    Science.gov (United States)

    He, Ruo; Wooller, Matthew J.; Pohlman, John W.; Catranis, Catharine; Quensen, John; Tiedje, James M.; Leigh, Mary Beth

    2012-01-01

    Arctic lakes are a significant source of the greenhouse gas methane (CH4), but the role that methane oxidizing bacteria (methanotrophs) play in limiting the overall CH4 flux is poorly understood. Here, we used stable isotope probing (SIP) techniques to identify the metabolically active aerobic methanotrophs in upper sediments (0–1 cm) from an arctic lake in northern Alaska sampled during ice-free summer conditions. The highest CH4 oxidation potential was observed in the upper sediment (0–1 cm depth) with 1.59 μmol g wet weight-1 day-1 compared with the deeper sediment samples (1–3 cm, 3–5 cm and 5–10 cm), which exhibited CH4 oxidation potentials below 0.4 μmol g wet weight-1 day-1. Both type I and type II methanotrophs were directly detected in the upper sediment total communities using targeted primer sets based on 16S rRNA genes. Sequencing of 16S rRNA genes and functional genes (pmoA and mxaF) in the 13C-DNA from the upper sediment indicated that type I methanotrophs, mainly Methylobacter, Methylosoma, Methylomonas and Methylovulum miyakonense, dominated the assimilation of CH4. Methylotrophs, including the genera Methylophilus and/or Methylotenera, were also abundant in the 13CDNA. Our results show that a diverse microbial consortium acquired carbon from CH4 in the sediments of this arctic lake.

  18. Contamination of arctic Fjord sediments by Pb-Zn mining at Maarmorilik in central West Greenland

    DEFF Research Database (Denmark)

    Perner, Kerstin; Leipe, Thomas; Dellwig, O;

    2010-01-01

    This study focuses on heavy metal contamination of arctic sediments from a small Fjord system adjacent to the Pb-Zn "Black Angel" mine (West Greenland) to investigate the temporal and spatial development of contamination and to provide baseline levels before the mines re-opening in January 2009...... illustrate this transport and spatial distribution pattern of the contaminated material....

  19. Increased accumulation of sulfur in lake sediments of the high Arctic

    DEFF Research Database (Denmark)

    Drevnick, Paul E.; Muir, Derek C.G.; Lamborg, Carl H.;

    2010-01-01

    stimulates dissimilatory sulfate reduction. The sulfide produced is stored in sediment (as acid volatile sulfide), converted to other forms of sulfur, or reoxidized to sulfate and lost to the water column. An acceleration of the sulfur cycle in Arctic lakes could have profound effects on important...

  20. Biochemical Characterization of a Family 15 Carbohydrate Esterase from a Bacterial Marine Arctic Metagenome

    Science.gov (United States)

    De Santi, Concetta; Willassen, Nils Peder

    2016-01-01

    Background The glucuronoyl esterase enzymes of wood-degrading fungi (Carbohydrate Esterase family 15; CE15) form part of the hemicellulolytic and cellulolytic enzyme systems that break down plant biomass, and have possible applications in biotechnology. Homologous enzymes are predicted in the genomes of several bacteria, however these have been much less studied than their fungal counterparts. Here we describe the recombinant production and biochemical characterization of a bacterial CE15 enzyme denoted MZ0003, which was identified by in silico screening of a prokaryotic metagenome library derived from marine Arctic sediment. MZ0003 has high similarity to several uncharacterized gene products of polysaccharide-degrading bacterial species, and phylogenetic analysis indicates a deep evolutionary split between these CE15s and fungal homologs. Results MZ0003 appears to differ from previously-studied CE15s in some aspects. Some glucuronoyl esterase activity could be measured by qualitative thin-layer chromatography which confirms its assignment as a CE15, however MZ0003 can also hydrolyze a range of other esters, including p-nitrophenyl acetate, which is not acted upon by some fungal homologs. The structure of MZ0003 also appears to differ as it is predicted to have several large loop regions that are absent in previously studied CE15s, and a combination of homology-based modelling and site-directed mutagenesis indicate its catalytic residues deviate from the conserved Ser-His-Glu triad of many fungal CE15s. Taken together, these results indicate that potentially unexplored diversity exists among bacterial CE15s, and this may be accessed by investigation of the microbial metagenome. The combination of low activity on typical glucuronoyl esterase substrates, and the lack of glucuronic acid esters in the marine environment suggest that the physiological substrate of MZ0003 and its homologs is likely to be different from that of related fungal enzymes. PMID:27433797

  1. Biochemical Characterization of a Family 15 Carbohydrate Esterase from a Bacterial Marine Arctic Metagenome.

    Directory of Open Access Journals (Sweden)

    Concetta De Santi

    Full Text Available The glucuronoyl esterase enzymes of wood-degrading fungi (Carbohydrate Esterase family 15; CE15 form part of the hemicellulolytic and cellulolytic enzyme systems that break down plant biomass, and have possible applications in biotechnology. Homologous enzymes are predicted in the genomes of several bacteria, however these have been much less studied than their fungal counterparts. Here we describe the recombinant production and biochemical characterization of a bacterial CE15 enzyme denoted MZ0003, which was identified by in silico screening of a prokaryotic metagenome library derived from marine Arctic sediment. MZ0003 has high similarity to several uncharacterized gene products of polysaccharide-degrading bacterial species, and phylogenetic analysis indicates a deep evolutionary split between these CE15s and fungal homologs.MZ0003 appears to differ from previously-studied CE15s in some aspects. Some glucuronoyl esterase activity could be measured by qualitative thin-layer chromatography which confirms its assignment as a CE15, however MZ0003 can also hydrolyze a range of other esters, including p-nitrophenyl acetate, which is not acted upon by some fungal homologs. The structure of MZ0003 also appears to differ as it is predicted to have several large loop regions that are absent in previously studied CE15s, and a combination of homology-based modelling and site-directed mutagenesis indicate its catalytic residues deviate from the conserved Ser-His-Glu triad of many fungal CE15s. Taken together, these results indicate that potentially unexplored diversity exists among bacterial CE15s, and this may be accessed by investigation of the microbial metagenome. The combination of low activity on typical glucuronoyl esterase substrates, and the lack of glucuronic acid esters in the marine environment suggest that the physiological substrate of MZ0003 and its homologs is likely to be different from that of related fungal enzymes.

  2. Occurrence and sorption properties of arsenicals in marine sediments

    DEFF Research Database (Denmark)

    Fauser, Patrik; Sanderson, Hans; Hedegaard, Rikke Susanne Vingborg;

    2013-01-01

    in the Baltic Sea and other parts of the world. Existing data for on-site measurements of sorption coefficients (Kd) of arsenicals in marine and freshwater sediments show large variability from 1,000 L/kg. In this work, calculated sorption coefficients (Kd and Koc) for As(III+V) showed significant correlation...... in marine sediments when conditions are similar to the Baltic Sea. At locations with significant anthropogenic point sources or where the local geology contains volcanic rock and sulphide mineral deposits, there may be significantly elevated arsenic concentrations, and it is recommended to determine on...

  3. Spatial issues in Arctic marine resource governance workshop summary and comment

    DEFF Research Database (Denmark)

    Kaiser, Brooks; Bakanev, Sergey; Bertelsen, Rasmus Gjedssø;

    2015-01-01

    The rapidly changing Arctic marine ecosystems face new challenges and opportunities that are increasing and shifting governance needs in the region. A group of economists, ecologists, biologists, political scientists and resource managers met in Stockholm, SE, Sept 4–6, 2014 to discuss...

  4. Spatial isses in Arctic marine resource governance workshop summary and comment

    DEFF Research Database (Denmark)

    Kaiser, Brooks; Bakanev, Sergey; Bertelsen, Rasmus;

    2015-01-01

    The rapidly changing Arctic marine ecosystems face new challenges and opportunities that are increasing and shifting governance needs in the region. A group of economists, ecologists, biologists, political scientists and resource managers met in Stockholm, SE, Sept 4–6, 2014 to discuss...

  5. Remnants of marine bacterial communities can be retrieved from deep sediments in lakes of marine origin.

    Science.gov (United States)

    Langenheder, Silke; Comte, Jérôme; Zha, Yinghua; Samad, Md Sainur; Sinclair, Lucas; Eiler, Alexander; Lindström, Eva S

    2016-08-01

    Some bacteria can be preserved over time in deep sediments where they persist either in dormant or slow-growing vegetative stages. Here, we hypothesized that such cells can be revived when exposed to environmental conditions similar to those before they were buried in the sediments. To test this hypothesis, we collected bacteria from sediment samples of different ages (140-8500 calibrated years before present, cal BP) from three lakes that differed in the timing of their physical isolation from the Baltic Sea following postglacial uplift. After these bacterial communities were grown in sterile water from the Baltic Sea, we determined the proportion of 16S rRNA sequence reads associated with marine habitats by extracting the environment descriptive terms of homologous sequences retrieved from public databases. We found that the proportion of reads associated with marine descriptive term was significantly higher in cultures inoculated with sediment layers formed under Baltic conditions and where salinities were expected to be similar to current levels. Moreover, a similar pattern was found in the original sediment layers. Our study, therefore, suggests that remnants of marine bacterial communities can be preserved in sediments over thousands of years and can be revived from deep sediments in lakes of marine origin. PMID:26929161

  6. Impacts of ocean acidification on sediment processes in shallow waters of the Arctic Ocean.

    Science.gov (United States)

    Gazeau, Frédéric; van Rijswijk, Pieter; Pozzato, Lara; Middelburg, Jack J

    2014-01-01

    Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster than those in sub-tropical regions. The present study investigates the effects of ocean acidification on sediment composition, processes and sediment-water fluxes in an Arctic coastal system. Undisturbed sediment cores, exempt of large dwelling organisms, were collected, incubated for a period of 14 days, and subject to a gradient of pCO2 covering the range of values projected for the end of the century. On five occasions during the experimental period, the sediment cores were isolated for flux measurements (oxygen, alkalinity, dissolved inorganic carbon, ammonium, nitrate, nitrite, phosphate and silicate). At the end of the experimental period, denitrification rates were measured and sediment samples were taken at several depth intervals for solid-phase analyses. Most of the parameters and processes (i.e. mineralization, denitrification) investigated showed no relationship with the overlying seawater pH, suggesting that ocean acidification will have limited impacts on the microbial activity and associated sediment-water fluxes on Arctic shelves, in the absence of active bio-irrigating organisms. Only following a pH decrease of 1 pH unit, not foreseen in the coming 300 years, significant enhancements of calcium carbonate dissolution and anammox rates were observed. Longer-term experiments on different sediment types are still required to confirm the limited impact of ocean acidification on shallow Arctic sediment processes as observed in this study.

  7. Arctic deltaic lake sediments as recorders of fluvial organic matter deposition

    Directory of Open Access Journals (Sweden)

    Jorien E Vonk

    2016-08-01

    Full Text Available Arctic deltas are dynamic and vulnerable regions that play a key role in land-ocean interactions and the global carbon cycle. Delta lakes may provide valuable historical records of the quality and quantity of fluvial fluxes, parameters that are challenging to investigate in these remote regions. Here we study lakes from across the Mackenzie Delta, Arctic Canada, that receive fluvial sediments from the Mackenzie River when spring flood water levels rise above natural levees. We compare downcore lake sediments with suspended sediments collected during the spring flood, using bulk (% organic carbon, % total nitrogen, 13C, 14C and molecular organic geochemistry (lignin, leaf waxes. High-resolution age models (137Cs, 210Pb of downcore lake sediment records (n=11 along with lamina counting on high-resolution radiographs show sediment deposition frequencies ranging between annually to every 15 years. Down-core geochemical variability in a representative delta lake sediment core is consistent with historical variability in spring flood hydrology (variability in peak discharge, ice jamming, peak water levels. Comparison with earlier published Mackenzie River depth profiles shows that (i lake sediments reflect the riverine surface suspended load, and (ii hydrodynamic sorting patterns related to spring flood characteristics are reflected in the lake sediments. Bulk and molecular geochemistry of suspended particulate matter from the spring flood peak and lake sediments are relatively similar showing a mixture of modern higher-plant derived material, older terrestrial permafrost material, and old rock-derived material. This suggests that deltaic lake sedimentary records hold great promise as recorders of past (century-scale riverine fluxes and may prove instrumental in shedding light on past behaviour of arctic rivers, as well as how they respond to a changing climate.

  8. Arctic deltaic lake sediments as recorders of fluvial organic matter deposition

    Science.gov (United States)

    Vonk, Jorien; Dickens, Angela; Giosan, Liviu; Zipper, Samuel; Galy, Valier; Holmes, Robert; Montlucon, Daniel; Kim, Bokyung; Hussain, Zainab; Eglinton, Timothy

    2016-08-01

    Arctic deltas are dynamic and vulnerable regions that play a key role in land-ocean interactions and the global carbon cycle. Delta lakes may provide valuable historical records of the quality and quantity of fluvial fluxes, parameters that are challenging to investigate in these remote regions. Here we study lakes from across the Mackenzie Delta, Arctic Canada, that receive fluvial sediments from the Mackenzie River when spring flood water levels rise above natural levees. We compare downcore lake sediments with suspended sediments collected during the spring flood, using bulk (% organic carbon, % total nitrogen, 13C, 14C) and molecular organic geochemistry (lignin, leaf waxes). High-resolution age models (137Cs, 210Pb) of downcore lake sediment records (n=11) along with lamina counting on high-resolution radiographs show sediment deposition frequencies ranging between annually to every 15 years. Down-core geochemical variability in a representative delta lake sediment core is consistent with historical variability in spring flood hydrology (variability in peak discharge, ice jamming, peak water levels). Comparison with earlier published Mackenzie River depth profiles shows that (i) lake sediments reflect the riverine surface suspended load, and (ii) hydrodynamic sorting patterns related to spring flood characteristics are reflected in the lake sediments. Bulk and molecular geochemistry of suspended particulate matter from the spring flood peak and lake sediments are relatively similar showing a mixture of modern higher-plant derived material, older terrestrial permafrost material, and old rock-derived material. This suggests that deltaic lake sedimentary records hold great promise as recorders of past (century-scale) riverine fluxes and may prove instrumental in shedding light on past behaviour of arctic rivers, as well as how they respond to a changing climate.

  9. Impacts of ocean acidification on sediment processes in shallow waters of the Arctic Ocean.

    Directory of Open Access Journals (Sweden)

    Frédéric Gazeau

    Full Text Available Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster than those in sub-tropical regions. The present study investigates the effects of ocean acidification on sediment composition, processes and sediment-water fluxes in an Arctic coastal system. Undisturbed sediment cores, exempt of large dwelling organisms, were collected, incubated for a period of 14 days, and subject to a gradient of pCO2 covering the range of values projected for the end of the century. On five occasions during the experimental period, the sediment cores were isolated for flux measurements (oxygen, alkalinity, dissolved inorganic carbon, ammonium, nitrate, nitrite, phosphate and silicate. At the end of the experimental period, denitrification rates were measured and sediment samples were taken at several depth intervals for solid-phase analyses. Most of the parameters and processes (i.e. mineralization, denitrification investigated showed no relationship with the overlying seawater pH, suggesting that ocean acidification will have limited impacts on the microbial activity and associated sediment-water fluxes on Arctic shelves, in the absence of active bio-irrigating organisms. Only following a pH decrease of 1 pH unit, not foreseen in the coming 300 years, significant enhancements of calcium carbonate dissolution and anammox rates were observed. Longer-term experiments on different sediment types are still required to confirm the limited impact of ocean acidification on shallow Arctic sediment processes as observed in this study.

  10. Long distance electron transmission couples sulphur, iron, calcium and oxygen cycling in marine sediment

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Nielsen, Lars Peter

    Geochemical observations in marine sediment have recently documented that electric currents may intimately couple spatially separated biogeochemical processes (1). When marine sediment rich in iron sulphide was exposed to oxygen we observed how the electric currents resulted in significant...

  11. Sediment Nitrification, Denitrification, and Nitrous Oxide Production in a Deep Arctic Lake †

    OpenAIRE

    Klingensmith, K. M.; Alexander, V.

    1983-01-01

    We used a combination of 15N tracer methods and a C2H2 blockage technique to determine the role of sediment nitrification and denitrification in a deep oligotrophic arctic lake. Inorganic nitrogen concentrations ranged between 40 and 600 nmol · cm−3, increasing with depth below the sediment-water interface. Nitrate concentrations were at least 10 times lower, and nitrate was only detectable within the top 0 to 6 cm of sediment. Eh and pH profiles showed an oxidized surface zone underlain by m...

  12. Marine Invasive Species Management: Adapting in the Arctic

    DEFF Research Database (Denmark)

    Kaiser, Brooks

    2014-01-01

    perturbations in the fragile Arctic ecosystems are likely to have outsized impacts both ecologically and economically. This paper discusses the optimal management of invasive species threats as a process that begins before the arrival of any species, with prevention, and continues in an integrated fashion...

  13. Future Arctic marine access: analysis and evaluation of observations, models, and projections of sea ice

    Directory of Open Access Journals (Sweden)

    T. S. Rogers

    2013-02-01

    Full Text Available There is an emerging need for regional applications of sea ice projections to provide more accuracy and greater detail to scientists, national, state and local planners, and other stakeholders. The present study offers a prototype for a comprehensive, interdisciplinary study to bridge observational data, climate model simulations, and user needs. The study's first component is an observationally based evaluation of Arctic sea ice trends during 1980–2008, with an emphasis on seasonal and regional differences relative to the overall pan-Arctic trend. Regional sea ice loss has varied, with a significantly larger decline of winter maximum (January–March extent in the Atlantic region than in other sectors. A lead–lag regression analysis of Atlantic sea ice extent and ocean temperatures indicates that reduced sea ice extent is associated with increased Atlantic Ocean temperatures. Correlations between the two variables are greater when ocean temperatures lag rather than lead sea ice. The performance of 13 global climate models is evaluated using three metrics to compare sea ice simulations with the observed record. We rank models over the pan-Arctic domain and regional quadrants and synthesize model performance across several different studies. The best performing models project reduced ice cover across key access routes in the Arctic through 2100, with a lengthening of seasons for marine operations by 1–3 months. This assessment suggests that the Northwest and Northeast Passages hold potential for enhanced marine access to the Arctic in the future, including shipping and resource development opportunities.

  14. Future Arctic marine access: analysis and evaluation of observations, models, and projections of sea ice

    Directory of Open Access Journals (Sweden)

    T. S. Rogers

    2012-09-01

    Full Text Available There is an emerging need for regional applications of sea ice projections to provide more accuracy and greater detail to scientists, national, state and local planners, and other stakeholders. The present study offers a prototype for a comprehensive, interdisciplinary study to bridge observational data, climate model simulations, and user needs. The study's first component is an observationally-based evaluation of Arctic sea ice trends during 1980–2008, with an emphasis on seasonal and regional differences relative to the overall pan-Arctic trend. Regional sea ice los has varied, with a significantly larger decline of winter maximum (January–March extent in the Atlantic region than in other sectors. A lead-lag regression analysis of Atlantic sea ice extent and ocean temperatures indicates that reduced sea ice extent is associated with increased Atlantic Ocean temperatures. Correlations between the two variables are greater when ocean temperatures lag rather than lead sea ice. The performance of 13 global climate models is evaluated using three metrics to compare sea ice simulations with the observed record. We rank models over the pan-Arctic domain and regional quadrants, and synthesize model performance across several different studies. The best performing models project reduced ice cover across key access routes in the Arctic through 2100, with a lengthening of seasons for marine operations by 1–3 months. This assessment suggests that the Northwest and Northeast Passages hold potential for enhanced marine access to the Arctic in the future, including shipping and resource development opportunities.

  15. Diversity, Persistence and Evolution in Marine Sediments

    DEFF Research Database (Denmark)

    Starnawski, Piotr

    2016-01-01

    detailed study we were also able to trace not only the same phyla but also the same species from the surface down to the deepest sediment. We’ve described these species as ”persister organisms”, and continued the work on describing them further. By using sequencing and bioinformatics tools we were able...

  16. Terrestiral plant biopolymers in marine sediments

    Energy Technology Data Exchange (ETDEWEB)

    Gough, M.A.; Fauzi, R.; Mantoura, C. (Plymouth Marine Lab. (United Kingdom)); Preston, M. (Univ. of Liverpool (United Kingdom))

    1993-03-01

    The vascular land plant biopolymers lignin and cutin were surveyed in the surface sediments of coastal and open ocean waters by controlled alkaline CuO oxidation/reaction. Two contrasting oceanic regimes were studied: the northwest Mediterranean (NWM) Sea, which receives significant particulate terrigenous debris through riverine discharge; and the northeast Atlantic (NEA) Ocean, with poorly characterized terrestrial carbon inputs. In the NWM products of lignin and cutin co-occurred at all stations, elevated levels (ca. 0.5-3.0 mg lignin phenols/100 mg organic carbon; ca. 0.01-0.09 mg cutin acids/100 mg organic carbon) were observed for near-shore deltaic and shelf sediments. The influence of terrestrial land plant inputs extended across the shelf and through the slope to the abyssal plain, providing molecular evidence for advective offshore transfer of terrestrial carbon. Mass balance estimates for the basin suggest riverine inputs account for the majority of surface sedimentary ligin/cutin, most of which (>90%) is deposited on the shelf. Products of CuO oxidation of lignin and cutin were also detected in NEA surface sediments, at levels comparable to those observed for the NWM continental slope, and were detectable at low concentrations in the sediments of the abyssal plains (>4,000 m depth). While atmospheric deposition of lignin/cutin-derived material cannot be discounted in this open ocean system, lateral advective transfer of enriched shelf sediments is inferred as a possible transport process. A progressive enrichment in cutin-derived material relative to lignin was observed offshore, with evidence of an increase in the degree of oxidative alteration of lignin residues. Preliminary mass balance calculations applied to the global ocean margin suggest riverine sources of both particulate lignin and cutin are important and that most (>95%) deposition of recognizable land plant biopolymers occurs in shelf seas. 74 refs., 7 figs., 5 tabs.

  17. Shifts in identity and activity of methanotrophs in arctic lake sediments in response to temperature changes

    Science.gov (United States)

    He, Ruo; Wooller, Matthew J.; Pohlman, John W.; Quensen, John; Tiedje, James M.; Leigh, Mary Beth

    2012-01-01

    Methane (CH4) flux to the atmosphere is mitigated via microbial CH4 oxidation in sediments and water. As arctic temperaturesincrease, understanding the effects of temperature on the activity and identity of methanotrophs in arctic lake sediments is importantto predicting future CH4 emissions. We used DNA-based stable-isotope probing (SIP), quantitative PCR (Q-PCR), andpyrosequencing analyses to identify and characterize methanotrophic communities active at a range of temperatures (4°C, 10°C,and 21°C) in sediments (to a depth of 25 cm) sampled from Lake Qalluuraq on the North Slope of Alaska. CH4 oxidation activitywas measured in microcosm incubations containing sediments at all temperatures, with the highest CH4 oxidation potential of37.5 mol g1 day1 in the uppermost (depth, 0 to 1 cm) sediment at 21°C after 2 to 5 days of incubation. Q-PCR of pmoA and ofthe 16S rRNA genes of type I and type II methanotrophs, and pyrosequencing of 16S rRNA genes in 13C-labeled DNA obtained bySIP demonstrated that the type I methanotrophs Methylobacter, Methylomonas, and Methylosoma dominated carbon acquisitionfrom CH4 in the sediments. The identity and relative abundance of active methanotrophs differed with the incubation temperature.Methylotrophs were also abundant in the microbial community that derived carbon from CH4, especially in the deeper sediments(depth, 15 to 20 cm) at low temperatures (4°C and 10°C), and showed a good linear relationship (R0.82) with the relativeabundances of methanotrophs in pyrosequencing reads. This study describes for the first time how methanotrophiccommunities in arctic lake sediments respond to temperature variations.

  18. Extending Hydrologic Information Systems to accommodate Arctic marine observations data

    Science.gov (United States)

    Hersh, Eric S.; Maidment, David R.

    2014-04-01

    The Chukchi Sea Offshore Monitoring in Drilling Area - Chemical and Benthos (COMIDA CAB) project characterizes the biota and chemistry of the continental shelf ecosystem of a region of the Chukchi Sea to form a baseline survey of environmental conditions before drilling for oil commences. This paper describes the COMIDA CAB project data and processing methods, which provide a novel approach to data tracking and archiving from marine sampling cruises. This approach features an adaptation of the Consortium of Universities for the Advancement of Hydrologic Science. Observations Data Model for application with physical, chemical, and biological oceanographic data - a new extension of the CUAHSI Hydrologic Information System - thus bringing hydroinformatics into the oceanographic realm. Environmental sampling has been carried out by five separate scientific teams who characterize particular classes of physical, chemical and biological variables, and who each have their own methods of processing samples in their laboratories following the two sampling cruises made to the Chukchi Sea in the summers of 2009 and 2010. The results of their observations and analyses are stored in data files, mostly in Excel format, whose structure is defined differently by each scientific team. In all, the 2009 and 2010 COMIDA CAB field efforts yielded a database of 510,405 data values. Of these, 474,129 were derived from continuous in-situ data sonde profiles and 36,276 were derived from non-sonde extracted samples of the sediment, epibenthos, and water column. These data values represent 301 variables measured at 65 sites and originated from 26 different source files. The biological observations represented 519 distinct taxa. The data from these files are transformed and synthesized into a comprehensive project database in which a set of standardized descriptors of each observed data value are specified and each data value is linked to the data file from which it was created to establish a

  19. Sorption behavior of nonylphenol on marine sediments: Effect of temperature, medium, sediment organic carbon and surfactant

    International Nuclear Information System (INIS)

    Highlights: → NP sorption kinetics accorded with non-linear Ho-McKay pseudo-second-order model. → Kd values showed positive correlation with sediment OC contents. → Medium salinity showed positive correlation with Kd and negative with DOC. → CTAB enhanced NP sorption amount the most while SDBS enhanced the lest. → NP sorption was an exothermic physical and spontaneous entropy-decreasing reaction. - Abstract: The sorption behavior of nonylphenol (NP, a toxic endocrine disruptor) on marine sediments was studied in detail through a series of kinetic and thermodynamic sorption experiments. The results showed that the sorption reaction of NP on marine sediments reached equilibrium in 1.5 h and that it accorded well with the non-linear Ho-McKay pseudo-second-order model. The sorption isotherms of NP on H2O-treated sediments could be well described by the Linear isotherm model, while the sorption isotherm on H2O2-treated sediments could be well fitted with the Freundlich isotherm model. A positive correlation was found between the distribution coefficient (Kd) and the sediment organic carbon contents. The medium salinity showed a positive relation with the Kd and a negative relation with the dissolved organic carbon (DOC). Hexadecyl trimethyl ammonium bromide (CTAB) enhanced the sorption amount of NP the most, while sodium dodecylbenzenesulfonate (SDBS) enhanced it the least. The sorption reaction of NP on marine sediments was a spontaneous, physical, exothermic and entropy-decreasing process.

  20. Influence of biochar amendments on marine sediment trace metal bioavailability

    Science.gov (United States)

    Gehrke, G. E.; Hsu-Kim, H.

    2014-12-01

    Biochar has become a desirable material for use in agricultural application to enhance soil quality and in-situ soil and sediment remediation to immobilize organic contaminants. We investigated the effects of biochar sediment amendments on the bioavailability of a suite of inorganic trace metals (Cr, Co, Ni, Cu, Zn, Pb) in contaminated sediments from multiple sites in Elizabeth River, VA. We incubated sediments in microcosms with a variety of water column redox and salinity conditions and compared sediments amended with two types of woody biochar to sediments amended with charcoal activated carbon and unamended sediments. We leached sediments in artificial gut fluid mimic of the benthic invertebrate Arenicola marina as a measure of bioavailability of the trace metals analyzed. In unamended anaerobic sediments, the gut fluid mimic leachable fraction of each trace metal is 1-4% of the total sediment concentration for each metal. Initial results indicate that in anaerobic microcosms, woody biochar sediment amendments (added to 5% dry wt) decrease the gut fluid mimic leachable fraction by 30-90% for all trace metals analyzed, and have comparable performance to charcoal activated carbon amendments. However, in microcosms without controlled redox conditions, woody biochar amendments increase the bioavailable fraction of Ni and Cu by up to 80%, while decreasing the bioavailable fraction of Co, Zn, and Pb by approximately 50%; charcoal activated carbon amendments decreased the bioavailability of all trace metals analyzed by approximately 20%. In microcosms without an overlying water column, biochar and activated carbon amendments had no significant effects on trace metal bioavailability. This research demonstrates that biochar can effectively decrease the bioavailability of trace metals in marine sediments, but its efficiency is metal-specific, and environmental conditions impact biochar performance.

  1. Evaluating Sediment Stability at Offshore Marine Hydrokinetic Energy Facilities

    Science.gov (United States)

    Jones, C. A.; Magalen, J.; Roberts, J.; Chang, G.

    2014-12-01

    Development of offshore alternative energy production methods through the deployment of Marine Hydrokinetic (MHK) devices (e.g. wave, tidal, and wind generators) in the United States continues at a rapid pace, with significant public and private investment in recent years. The installation of offshore MHK systems includes cabling to the shoreline and some combination of bottom foundation (e.g., piles, gravity bases, suction buckets) or anchored floating structure. Installation of any of this infrastructure at the seabed may affect coastal sediment dynamics. It is, therefore, necessary to evaluate the interrelationships between hydrodynamics and seabed dynamics and the effects of MHK foundations and cables on sediment transport. If sufficient information is known about the physical processes and sediment characteristics of a region, hydrodynamic and sediment transport models may be developed to evaluate near and far-field sediment transport. The ultimate goal of these models and methods is to quantitatively evaluate changes to the baseline seabed stability due to the installation of MHK farms in the water. The objective of the present study is to evaluate and validate wave, current, and sediment transport models (i.e., a site analysis) that may be used to estimate risk of sediment mobilization and transport. While the methodology and examples have been presented in a draft guidance document (Roberts et al., 2013), the current report presents an overall strategy for model validation, specifically for a case study in the Santa Cruz Bight, Monterey Bay, CA. Innovative techniques to quantify the risk of sediment mobility has been developed to support these investigations. Public domain numerical models are utilized to estimate the near-shore wave climate (SWAN: Simulating Waves Near-shore) and circulation and sediment transport (EFDC: Environmental Fluid Dynamics Code) regimes. The models were validated with field hydrodynamic data. Sediment size information was

  2. Hotspots in cold seas: The composition, distribution, and abundance of marine birds in the North American Arctic

    Science.gov (United States)

    Wong, Sarah N. P.; Gjerdrum, Carina; Morgan, Ken H.; Mallory, Mark L.

    2014-03-01

    The distribution and thickness of sea ice in the Arctic is changing rapidly, resulting in changes to Arctic marine ecosystems. Seabirds are widely regarded as indicators of marine environmental change, and understanding their distribution patterns can serve as a tool to monitor and elucidate biological changes in the Arctic seas. We examined the at-sea distribution of seabirds in the North American Arctic in July and August, 2007-2012, and marine areas of high density were identified based on bird densities for four foraging guilds. Short-tailed shearwaters (Puffinus tenuirostris) were the most abundant species observed. Northern fulmars (Fulmarus glacialis), thick-billed murres (Uria lomvia), and dovekies (Alle alle) were also sighted in large numbers. Few birds were sighted between Dolphin and Union Strait and King William Island. Areas of high density over multiple years were found throughout the entire western portion of the study area (Bering Sea, Bering Strait, and Chukchi Sea), Lancaster Sound, Baffin Bay, Davis Strait, and the low Arctic waters off Newfoundland. These waters are characterized by high primary productivity. This study is the first to document the marine distribution of seabirds across the entire North American Arctic within the same time period, providing a critical baseline for monitoring the distribution and abundance of Arctic seabirds in a changing Arctic seascape.

  3. Dating methods about bulk sediments in marine environment

    International Nuclear Information System (INIS)

    With the development of science and technology progress, the studies about dating methods of sediments become more and more precise. Widely used of so many dating methods have offered reliable scientific evidence for the foundation of accurate chronostratigraphic framework in different region. Considering the difference of sedimentary environment as well as sediment types between inland and submarine, the dating method should be secerned. However, there are few articles which specially introduce the dating methods about bulk sediments in submarine environment. Based on the conclusion and summarized about many dating methods, especially focus on the sediment types and dating range,the conformable isotope dating methods (210Pb, 14C), OSL dating and comparatively dating methods (ie., Oxygen isotope curve, Paleomagnetic) which suitable for the bulk sediments in marine environment are suggested. Dating have an very important function in marine geological studies. In order to enhance the veracity and reliability of the dating data, the proper methods based on sediment types and estimated age range are selected. On the other hand,the progress cross-comparison during different dating methods are given. (authors)

  4. Potential radiocarbon chronology tool using archaeal tetraether lipids for the western Arctic Ocean sediment

    Science.gov (United States)

    Uchida, M.; Kondo, M.; Utsumi, M.; Shibata, Y.

    2011-12-01

    The Arctic Ocean plays a major role in global climate changes by changing global energy balance through ice-albedo feedback and by affecting the oceanic thermohaline circulation through the water exchange with the Atlantic and Pacific Ocean. For future prediction of those changes in Arctic Ocean it is necessary to reconstruct details of past climate history with accurate age model. However, it is not easy to make age model of sediment cores covering late Pleistocene-Holocene transition including global abrupt climate change because preservation of carbonate fossil such as planktonic foraminifera is very limited. In the glacial time, foraminifera is almost barren. Thus, so far climate history in the Arctic Ocean environment is poorly understood. For these reasons, we are looking for alternative chronological target instead of foraminifera. In this study, radiocarbon contents of archaeal glycerol dibiphytanyl glycerol tetraether lipids (GDGTs) from Arctic surface sediments, which is also used for paleothermometry, were measured and compared with those of dissolved inorganic carbon (DIC) of sea water, planktonic and benthic foraminifera, shell, and bulk organic matter in the same horizons. We will discuss potential as chronology using the GDGTs and carbon sources of these compounds.

  5. Trophodynamics of some PFCs and BFRs in a western Canadian Arctic marine food web.

    Science.gov (United States)

    Tomy, Gregg T; Pleskach, Kerri; Ferguson, Steve H; Hare, Jonathon; Stern, Gary; Macinnis, Gordia; Marvin, Chris H; Loseto, Lisa

    2009-06-01

    The trophodynamics of per- and polyfluorinated compounds and bromine-based flame retardants were examined in components of a marine food web from the western Canadian Arctic. The animals studied and their relative trophic status in the food web, established using stable isotopes of nitrogen (delta15N), were beluga (Delphinapterus leucas) > ringed seal (Phoca hispida) > Arctic cod (Boreogadus saida) > Pacific herring (Clupea pallasi) approximately equal to Arctic cisco (Coregonus autumnalis) > pelagic amphipod (Themisto libellula) > Arctic copepod (Calanus hyperboreus). For the brominated diphenyl ethers, the lipid adjusted concentrations of the seven congeners analyzed (Sigma7BDEs: -47, -85, -99, -100, -153, -154, and -209) ranged from 205.4 +/- 52.7 ng/g in Arctic cod to 2.6 +/- 0.4 ng/g in ringed seals. Mean Sigma7BDEs concentrations in Arctic copepods, 16.4 ng/g (n = 2, composite sample), were greater than those in the top trophic level (TL) marine mammals and suggests that (i) Arctic copepods are an important dietary component that delivers BDEs to the food web and (ii) because these compounds are bioaccumulative, metabolism and depletion of BDE congeners in top TL mammals is an important biological process. There were differences in the concentration profiles of the isomers of hexabromocyclododecane (HBCD) in the food web. The most notable difference was observed for beluga, where the alpha-isomer was enriched (accounting for approximately 90% of the SigmaHBCD body burden), relative to its primary prey species, Arctic cod, where the alpha-isomer accounted for only 20% of the SigmaHBCD body burden (beta: 4% and gamma: 78%). For the C8-C11 perfluorinated carboxylic acids, the trophic magnification factors (TMFs) were all greater than unity and increased with increasing carbon chain length. PFOS and its neutral precursor, PFOSA, also had TMF values greater than one. There were also pronounced differences in the PFOSA to PFOS ratio in ringed seal (0.04) and in

  6. Mycodiversity in marine sediments contaminated by heavy metals: preliminary results

    Science.gov (United States)

    Zotti, Mirca; Carbone, Cristina; Cecchi, Grazia; Consani, Sirio; Cutroneo, Laura; Di Piazza, Simone; Gabutto, Giacomo; Greco, Giuseppe; Vagge, Greta; Capello, Marco

    2016-04-01

    Fungi represent the main decomposers of woody and herbaceous substrates in the marine ecosystems. To date there is a gap in the knowledge about the global diversity and distribution of fungi in marine habitats. On the basis of their biological diversity and their role in ecosystem processes, marine fungi may be considered one of the most attractive groups of organisms in modern biotechnology, e.g. ecotoxic metal bioaccumulation. Here we report the data about the first mycological survey in the metal contaminated coastal sediments of the Gromolo Bay. The latter is located in Ligurian Sea (Eastern Liguria, Italy) and is characterized by an enrichment of heavy metals due to pollution of Gromolo Torrent by acidic processes that interest Fe-Cu sulphide mine. 24 samples of marine sediments were collected along a linear plot in front of the shoreline in July 2015. Each sample was separated into three aliquot for mineralogical, chemical analyses and fungal characterization. The sediment samples are characterised by clay fractions (illite and chlorite), minerals of ophiolitic rocks (mainly serpentine, pyroxene and plagioclase) and quartz and are enriched some chemical elements of environmental importance (such as Cu, Zn, Pb, Cd, As). For fungal characterisation the sediment samples were inoculated in Petri dishes on different culture media (Malt Extract Agar and Rose Bengal) prepared with sea water and added with antibiotics. The inoculated dishes were incubated at 20°C in the dark for 28 days. Every week fungal growth was monitored counting the number of colonies. Later, the colonies were isolated in axenic culture for further molecular analysis. The mycodiversity evaluate on the basis of Colony Forming Units (CFU) and microfungal-morphotype characterised by macro-and micro-morphology. Until now on the 72 Petri dishes inoculated 112 CFU of filamentous fungi were counted, among these about 50 morphotypes were characterized. The quantitative results show a mean value of 4

  7. Pollution of the Marine Environment by Dumping: Legal Framework Applicable to Dumped Chemical Weapons and Nuclear Waste in the Arctic Ocean

    OpenAIRE

    Lott, Alexander

    2016-01-01

    The Arctic seas are the world’s biggest dumping ground for sea-disposed nuclear waste and have served among the primary disposal sites for chemical warfare agents. Despite of scientific uncertainty, the Arctic Council has noted that this hazardous waste still affects adversely the Arctic marine environment and may have implications to the health of the Arctic people. The purpose of this manuscript is to establish the rights and obligations of the Arctic States in c...

  8. Remobilization of Iodine in Marine Sediments During Early Diagenesis

    Institute of Scientific and Technical Information of China (English)

    程先豪

    1993-01-01

    Based on the sedimentary geochemical studies of the Antarctic Ocean and the various geochemical parameters available,this paper deals with the process of emobilization of iodine in marine sediments during early diagenesis.The results showed that the process is not always controlled completely by organic matter as was expected previously.On average the adsorption and oxide phases of iodine account respectively for 23% and 32% of the total in continental-shelf and hemipelagic surficial sediments.Chemical analysis has revealed that the upward diffusion flux and redox conditions would play an important role in the concentration of iodine in the surface sediments.And the species of iodine in the surfial sediments characteristic of high I/Corg ratios would bepredominated by the oxide and adsorption phases.As experimentally evidenced,it is the early diagenetic remoibilization of iodine associated with the oxide and adsorption phases that led to the decrease of I/Corg with increasing depth.Calculations suggested that the diffusion flux of iodine from the deep parts of te sedimentary columum upwards is on the same order of magnitude as the deposition flux of it from sea water.This may be one of the important factors leading to the depletion of iodine in sedimentary rocks.On the basis of the above discussion and calculations the author has proposed a model for the remobilization of iodine in marine sediments during early diagenesis.

  9. In Situ burning of Arctic marine oil spills

    DEFF Research Database (Denmark)

    Fritt-Rasmussen, Janne

    Oil spills in ice filled and Arctic waters pose other challenges for oil spill response compared to open and temperate waters. In situ burning has been proven to be an effective oil spill response method for oil spills in ice filled waters. This thesis presents results from laboratory and field...... experiments where the ignitability of oil spill as a function of oil type and weathering conditions (time/ice) was tested. The results show that the composition of the oil and the ice cover is important for the in situ burning time-window. The results were used to develop an algorithm that was implemented...

  10. Influence of macrobenthos on chemical diagenesis of marine sediments

    Energy Technology Data Exchange (ETDEWEB)

    Aller, R.C.

    1977-05-01

    Diagenetic reactions involving the decomposition of organic matter and the dissolution, mobilization, and reprecipitation of metals sensitive to oxidation-reduction reactions, are most intense and rapid in the upper 1 m and especially the upper 10 cm of marine sediment. It is in this upper zone where most benthic organisms live and interact with sediments and where exchange rates of dissolved and particulate material between sediment and overlying water are largely determined. In Long Island Sound, U.S.A., both spatial and temporal trends in sediment chemistry and the flux of material out of the bottom demonstrate the control of diagenesis by bottom fauna. /sup 234/Th//sup 238/U disequilibrium studies demonstrate that particle reworking rates near the sediment-water interface vary both temporally and spatially in the Sound. The most rapid reworking occurs in protobranch-inhabited bottom areas as do the highest /sup 234/Th inventories. Excess /sup 234/Th profiles in the sediment allow determination of the rates of selected diagenetic reactions, such as Mn/sup + +/ production, near the sediment surface. Both the /sup 234/Th disequilibrium and flux measurements indicate that intra-estuarine redistribution of metals continually takes place.

  11. Heterotrophic potential of Atribacteria from deep marine Antarctic sediment

    Science.gov (United States)

    Carr, S. A.; Orcutt, B.; Mandernack, K. W.; Spear, J. R.

    2015-12-01

    Bacteria belonging to the newly classified candidate phylum "Atribacteria" (formerly referred to as "OP9" and "JS1") are common in anoxic methane-rich sediments. However, the metabolic functions and biogeochemical role of these microorganisms in the subsurface remains unrealized due to the lack of pure culture representatives. This study observed a steady increase of Atribacteria-related sequences with increasing sediment depth throughout the methane-rich zone of the Adélie Basin, Antarctica (according to a 16S rRNA gene survey). To explore the functional potential of Atribacteria in this basin, samples from various depths (14, 25 and 97 meters below seafloor), were subjected to metagenomic sequencing. Additionally, individual cells were separated from frozen, unpreserved sediment for whole genome amplification. The successful isolation and sequencing of a single-amplified Atribacteria genome from these unpreserved sediments demonstrates a future use of single cell techniques with previously collected and frozen sediments. Our resulting single-cell amplified genome, combined with metagenomic interpretations, provides our first insights to the functional potential of Atribacteria in deep subsurface settings. As observed for non-marine Atribacteria, genomic analyses suggest a heterotrophic metabolism, with Atribacteria potentially producing fermentation products such as acetate, ethanol and CO2. These products may in turn support methanogens within the sediment microbial community and explain the frequent occurrence of Atribacteria in anoxic methane-rich sediments.

  12. Characterization of Tunisian marine sediments in Rades and Gabes harbors

    Institute of Scientific and Technical Information of China (English)

    Imen BEL HADJ ALI; Zoubeir LAFHAJ; Mounir BOUASSIDA; Imen SAID

    2014-01-01

    The objective of this article is to study the geotechnical and environmental characteristics of sediments dredged from two Tunisian harbors:Rades and Gabes. The first harbor represents the main facility place in the national transport chain. The second one is selected as its sediments present a serious ecological constraint caused by the discharge of wastes into the marine environment. These sediments are either discarded at sea or landfilled despite their harmful effects on the environment. The article is divided into three main sections. The first one presents the material that was carried for Rades and Gabes harbors. The conservation conditions and the used experimental tests are detailed. Geotechnical characterization includes the determination of the grain size distribution, the water content, the Atterberg limits, the methylene blue value, the specific area, the bulk density, the specific unit weight, the organic and carbonate contents. Environmental characterization is assessed by the determination of metals concentrations in a leaching solution. The second section deals with the description and analysis of geotechnical properties of Rades and Gabes harbors’ sediments. The results obtained show that Rades harbor sediments are slightly sandy clayey silts whereas Gabes harbor sediments are silty sands characterized by a highly plastic clay fraction. Both of the two sediments don’t exhibit a high organic content. Finally, chemical, mineralogical and environmental properties are presented and then analysed. The experimental results obtained show that Rades and Gabes sediments could be used as a sand substitute in the formulation of a new construction material. Gabes harbor sediments are more polluted than Rades harbor sediments.

  13. Diversity and Composition of Bacterial Community in Soils and Lake Sediments from an Arctic Lake Area

    Science.gov (United States)

    Wang, Neng Fei; Zhang, Tao; Yang, Xiao; Wang, Shuang; Yu, Yong; Dong, Long Long; Guo, Yu Dong; Ma, Yong Xing; Zang, Jia Ye

    2016-01-01

    This study assessed the diversity and composition of bacterial communities within soils and lake sediments from an Arctic lake area (London Island, Svalbard). A total of 2,987 operational taxonomic units were identified by high-throughput sequencing, targeting bacterial 16S rRNA gene. The samples from four sites (three samples in each site) were significantly different in geochemical properties and bacterial community composition. Proteobacteria and Acidobacteria were abundant phyla in the nine soil samples, whereas Proteobacteria and Bacteroidetes were abundant phyla in the three sediment samples. Furthermore, Actinobacteria, Chlorobi, Chloroflexi, Elusimicrobia, Firmicutes, Gemmatimonadetes, Nitrospirae, Planctomycetes, Proteobacteria significantly varied in their abundance among the four sampling sites. Additionally, members of the dominant genera, such as Clostridium, Luteolibacter, Methylibium, Rhodococcus, and Rhodoplanes, were significantly different in their abundance among the four sampling sites. Besides, distance-based redundancy analysis revealed that pH (p soils and sediments from a lake area in the Arctic harbor a high diversity of bacterial communities, which are influenced by many geochemical factors of Arctic environments.

  14. NOAA Atmospheric, Marine and Arctic Monitoring Using UASs (including Rapid Response)

    Science.gov (United States)

    Coffey, J. J.; Jacobs, T.

    2015-12-01

    Unmanned systems have the potential to efficiently, effectively, economically, and safely bridge critical observation requirements in an environmentally friendly manner. As the United States' Atmospheric, Marine and Arctic areas of interest expand and include hard-to-reach regions of the Earth (such as the Arctic and remote oceanic areas) optimizing unmanned capabilities will be needed to advance the United States' science, technology and security efforts. Through increased multi-mission and multi-agency operations using improved inter-operable and autonomous unmanned systems, the research and operations communities will better collect environmental intelligence and better protect our Country against hazardous weather, environmental, marine and polar hazards. This presentation will examine NOAA's Atmospheric, Marine and Arctic Monitoring Unmanned Aircraft System (UAS) strategies which includes developing a coordinated effort to maximize the efficiency and capabilities of unmanned systems across the federal government and research partners. Numerous intra- and inter-agency operational demonstrations and assessments have been made to verify and validated these strategies. This includes the introduction of the Targeted Autonomous Insitu Sensing and Rapid Response (TAISRR) with UAS concept of operations. The presentation will also discuss the requisite UAS capabilities and our experience in using them.

  15. Diversity and physiology of marine lignicolous fungi in Arctic waters: a preliminary account

    Directory of Open Access Journals (Sweden)

    Ka-Lai Pang

    2011-01-01

    Full Text Available Information on the diversity of marine fungi in polar environments is lacking, especially marine fungi colonizing wood. During visits to Tromsø and Longyearbyen, Norway, drift and trapped wood was collected to provide a preliminary account of lignicolous marine fungi in Arctic waters. Six marine fungi were recorded from 24 and 27 samples of wood from Tromsø and Longyearbyen, respectively. Among these, four marine fungi new to science were identified from wood collected at Longyearbyen. To shed light on the ecological role of this group of fungi in the Arctic, a physiological study of one of the collected fungi, Havispora longyearbyenensis, was conducted. H. longyearbyenensis grew at 4 °C, 10 °C, 15 °C and 20 °C in all salinities tested (0 0/00, 17 0/00, 34 0/00. However, growth was significantly reduced at 4 °C and 0 0/00 salinity. The optimal condition for growth of H. longyearbyenensis was at 20 °C in all salinities tested.

  16. Distribution of benthic foraminifers (>125 um) in the surface sediments of the Arctic Ocean

    Science.gov (United States)

    Osterman, Lisa E.; Poore, Richard Z.; Foley, Kevin M.

    1999-01-01

    Census data on benthic foraminifers (>125 ?m) in surface sediment samples from 49 box cores are used to define four depth-controlled biofacies, which will aid in the paleoceanographic reconstruction of the Arctic Ocean. The shelf biofacies contains a mix of shallow-water calcareous and agglutinated species from the continental shelves of the Beaufort and Chukchi Seas and reflects the variable sedimentologic and oceanic conditions of the Arctic shelves. The intermediate-depth calcareous biofacies, found between 500 and 1,100 meters water depth (mwd), contains abundant Cassidulina teretis , presumably indicating the influence of Atlantic-derived water at this depth. In water depths between 1,100 and 3,500 m, a deepwater calcareous biofacies contains abundant Oridorsalis umbonatus . Below 3,500 mwd, the deepwater mixed calcareous/agglutinated biofacies of the Canada, Makarov, and Eurasian Basins reflects a combination of low productivity, dissolution, and sediment transport. Two other benthic foraminiferal species show specific environmental preferences. Fontbotia wuellerstorfi has a depth distribution between 900 and 3,500 mwd, but maximum abundance occurs in the region of the Mendeleyev Ridge. The elevated abundance of F. wuellerstorfi may be related to increased food supply carried by a branch of Atlantic water that crosses the Lomonosov Ridge near the Russian Continental Shelf. Triloculina frigida is recognized to be a species preferring lower slope sediments commonly disturbed by turbidites and bottom currents. INTRODUCTION At present, our understanding of the Arctic Ocean lags behind our understanding of other oceans, and fundamental questions still exist about its role in and response to global climate change. The Arctic Ocean is particularly sensitive to climatic fluctuations because small changes in the amounts of sea-ice cover can alter global albedo and thermohaline circulation (Aagaard and Carmack, 1994). Numerous questions still exist regarding the nature

  17. Biogenic methane potential of marine sediments. Application of chemical thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Arning, E.T.; Schulz, H.M. [Helmholtz Centre Potsdam GFZ, Potsdam (Germany); Berk, W. van [Technical Univ. of Clausthal (Germany). Dept. of Hydrogeology

    2013-08-01

    Accumulations of biogenic methane-dominated gas are widespread and occur in a variety of depositional settings and rock types. However, the potential of biogenic methane remains underexplored. This is mainly due to the fact that quantitative assessments applying numerical modeling techniques for exploration purposes are generally lacking to date. Biogenic methane formation starts in relatively shallow marine sediments below the sulfate reduction zone. When sulfate is exhausted, methanogenesis via the CO{sub 2} reduction pathway is often the dominant biogenic methane formation process in marine sediments (Claypool and Kaplan, 1974). The process can be simplified by the reaction: 2CH{sub 2}O + Ca{sup 2+} + H{sub 2}O {yields} CH{sub 4} + CaCO{sub 3} + 2H{sup +}. The products of early diagenetic reactions initiate coupled equilibrium reactions that induce a new state of chemical equilibrium among minerals, pore water and gas. The driving force of the complex biogeochemical reactions in sedimentary environments during early diagenesis is the irreversible redox-conversion of organic matter. Early diagenetic formation of biogenic methane shortly after deposition ('early diagenesis') was retraced using PHREEQC computer code that is applied to calculate homogenous and heterogeneous mass-action equations in combination with one-dimensional diffusion driven transport (Parkhurst and Appelo, 1999). Our modeling approach incorporates interdependent diagenetic reactions evolving into a diffusive multi-component and multiphase system by means of thermodynamic equilibrium calculations of species distribution (Arning et al., 2011, 2012, 2013). Reaction kinetics of organic carbon conversion is integrated into the set of equilibrium reactions by defining type and amount of converted organic matter in a certain time step. It is the aim (1) to calculate quantitatively thermodynamic equilibrium conditions (composition of pore water, mineral phase and gas phase assemblage) in

  18. The bioremediation potential of marine sandy sediment microbiota

    OpenAIRE

    Dan Răzvan POPOVICIU

    2012-01-01

    The natural microbiota from marine sandy sediments on the Romanian sea coast was tested for resilience in case of hydrocarbon contamination, for estimating the number of (culturable) hydrocarbon and lipid oil-degrading microorganisms and for determining the influence of inorganic nitrate and phosphate nutrients on hydrocarbon spill bioremediation process, by microcosm experiments.Results show that hydrocarbon contamination affects the bacteriobenthos both in terms of cell numbers and composit...

  19. Analysis of sea ice and phytoplankton biomarkers in marine sediments from the Nordic Seas - a calibration study

    Science.gov (United States)

    Navarro Rodriguez, A.; Cabedo Sanz, P.; Belt, S.; Brown, T.; Knies, J.; Husum, K.; Giraudeau, J.

    2012-04-01

    The work presented here is part of the Changing Arctic and SubArctic Environment program (EU CASE) which is an Initial Training Network (ITN) on climate change and marine environment and is an interdisciplinary project focussing on biological proxies. One of these proxies is the sea ice diatom biomarker IP25 which is a highly branched isoprenoid (HBI) alkene synthesised by some Arctic sea-ice diatoms and has been shown to be a specific, stable and sensitive proxy measure of Arctic sea ice when detected in underlying sediments (Belt et al., 2007). The current study focuses on two key elements: (1) An analytical calibration of IP25 isolated from marine sediments and purified using a range of chromatographic methods was conducted in order to improve the quantification of this biomarker in sediment extracts. (2) Analysis of >30 near-surface sediments from the Nordic Seas was carried out to quantify biomarkers previously suggested as indicators of open-water phytoplankton (brassicasterol) (Müller et al., 2011) and sea-ice (IP25) conditions (Belt et al., 2010). The outcomes of the biomarker analyses were used to make comparisons between proxy data and known sea ice conditions in the study area derived from satellite record over the last 20 years. The results of this study should inform longer timescale reconstructions of sea ice conditions in the Nordic sea in the future. Belt, S.T., Massé, G., Rowland. S.J., Poulin. M., Michel. C., LeBlanc. B., (2007). A novel chemical fossil of palaeo sea ice : IP25 . Organic Geochemistry 38 (16-27). Belt, S. T., Vare, L. L., Massé, G., Manners, H. R., Price, J. C., MacLachlan, S. E., Andrews, J. T. & Schmidt, S. (2010) 'Striking similarities in temporal changes to spring sea ice occurrence across the central Canadian Arctic Archipelago over the last 7000 years', Quaternary Science Reviews, 29 (25-26), pp. 3489-3504. Müller, J., Wagner, A., Fahl, K., Stein, R., Prange, M., & Lohmann, G. (2011). Towards quantitative sea ice

  20. Simulated and observed trends in key variables of the Arctic marine carbon cycle

    Science.gov (United States)

    Goris, Nadine; Heinze, Christoph; Lauvset, Siv; Petrenko, Dmitry; Pozdnyakov, Dmitry; Schwinger, Jörg

    2013-04-01

    For the Arctic region, a thorough monitoring of the marine carbon cycle is important, as the general "polar amplification" of climate change also translates into the biogeochemical realm. As compared to the global ocean, the sink for human-produced CO2 is fairly small in the Arctic Ocean itself. Nevertheless, it is important to follow up this Arctic sink as a further control of the regional carbon budget and to record changes in the marine carbon cycle on the way towards a "blue Arctic". Since observations on the Arctic are rare, the EU FP7 MONARCH-A project tries to enable adequate descriptions of the status and evolution of the Arctic region Earth system components by generating time series of observation datasets and model hindcasts. In terms of the marine carbon cycle, this analysis focuses mainly on the key variables pCO2 and primary productivity. For oceanic pCO2, the comprehensive data-sets SOCAT and LDEO were combined, while measurements of atmospheric CO2 were collected from the GLOBALVIEW-CO2 data integration project. Monthly Primary Production fields were retrieved from the sensors MODIS and SeaWiFs. In order to get an overall picture of the behavior and trends of those key variables, in addition the physical-biogeochemical model MICOM-HAMOCC-M was employed. The investigation showed that both oceanic and atmospheric pCO2 are consistent variables which have a regular annual cycle and a similar behaviour all over the Arctic for both model and data. In contrast, primary production shows an irregular annual cycle in both range and form, varying over the Arctic. While a few well distributed measurement stations with continuous observations are sufficient to get a comprehensive picture for consistent variables like pCO2, it is relatively difficult and costly to get a comprehensive record of non-consistent variables. Since the provided data-set for primary production covers a relatively short time-scale, it was neither possible to confidently validate the model

  1. Demethylation and cleavage of dimethylsulfoniopropionate in marine intertidal sediments

    Science.gov (United States)

    Visscher, P.T.; Kiene, R.P.; Taylor, B.F.

    1994-01-01

    Demethylation and cleavage of dimethylsulfoniopropionate (DMSP) was measured in three different types of,intertidal marine sediments: a cyanobacterial mat, a diatom-covered tidal flat and a carbonate sediment. Consumption rates of added DMSP were highest in cyanobacterial mat slurries (59 ?? mol DMSP l-1 slurry h-1) and lower in slurries from a diatom mat and a carbonate tidal sediment (24 and 9 ??mol DMSP l-1 h-1, respectively). Dimethyl sulfide (DMS) and 3-mercaptopropionate (MPA) were produced simultaneously during DMSP consumption, indicating that cleavage and demethylation occurred at the same time. Viable counts of DMSP-utilizing bacteria revealed a population of 2 x 107 cells cm-3 sediment (90% of these cleaved DMSP to DMS, 10% demethylated DMSP to MPA) in the cyanobacterial mat, 7 x 105 cells cm-3 in the diatom mat (23% cleavers, 77% demethylators), and 9 x 104 cells cm-3 (20% cleavers and 80% demethylators) in the carbonate sediment. In slurries of the diatom mat, the rate of MPA production from added 3-methiolpropionate (MMPA) was 50% of the rate of MPA formation from DMSP. The presence of a large population of demethylating bacteria and the production of MPA from DMSP suggest that the demethylation pathway, in addition to cleavage, contributes significantly to DMSP consumption in coastal sediments.

  2. Succession of cable bacteria and electric currents in marine sediment

    DEFF Research Database (Denmark)

    Schauer, Regina; Risgaard-Petersen, Nils; Kjeldsen, Kasper Urup;

    2014-01-01

    current density and biomass declined after 13 and 21 days, respectively. This might reflect a breakdown of short filaments as their solid sulphide sources became depleted in the top layers of the anoxic zone. In conclusion, cable bacteria combine rapid and efficient growth with oriented movement......Filamentous Desulfobulbaceae have been reported to conduct electrons over centimetre-long distances, thereby coupling oxygen reduction at the surface of marine sediment to sulphide oxidation in sub-surface layers. To understand how these /`cable bacteria/' establish and sustain electric...... conductivity, we followed a population for 53 days after exposing sulphidic sediment with initially no detectable filaments to oxygen. After 10 days, cable bacteria and electric currents were established throughout the top 15[thinsp]mm of the sediment, and after 21 days the filament density peaked with a total...

  3. The chromium isotope composition of reducing and oxic marine sediments

    Science.gov (United States)

    Gueguen, Bleuenn; Reinhard, Christopher T.; Algeo, Thomas J.; Peterson, Larry C.; Nielsen, Sune G.; Wang, Xiangli; Rowe, Harry; Planavsky, Noah J.

    2016-07-01

    The chromium (Cr) isotope composition of marine sediments has the potential to provide new insights into the evolution of Earth-surface redox conditions. There are significant but poorly constrained isotope fractionations associated with oxidative subaerial weathering and riverine transport, the major source of seawater Cr, and with partial Cr reduction during burial in marine sediments, the major sink for seawater Cr. A more comprehensive understanding of these processes is needed to establish global Cr isotope mass balance and to gauge the utility of Cr isotopes as a paleoredox proxy. For these purposes, we investigated the Cr isotope composition of reducing sediments from the upwelling zone of the Peru Margin and the deep Cariaco Basin. Chromium is present in marine sediments in both detrital and authigenic phases, and to estimate the isotopic composition of the authigenic fraction, we measured δ53Cr on a weakly acid-leached fraction in addition to the bulk sediment. In an effort to examine potential variability in the Cr isotope composition of the detrital fraction, we also measured δ53Cr on a variety of oxic marine sediments that contain minimal authigenic Cr. The average δ53Cr value of the oxic sediments examined here is -0.05 ± 0.10‰ (2σ, n = 25), which is within the range of δ53Cr values characteristic of the bulk silicate Earth. This implies that uncertainty in estimates of authigenic δ53Cr values based on bulk sediment analyses is mainly linked to estimation of the ratio of Cr in detrital versus authigenic phases, rather than to the Cr-isotopic composition of the detrital pool. Leaches of Cariaco Basin sediments have an average δ53Cr value of +0.38 ± 0.10‰ (2σ, n = 7), which shows no dependency on sample location within the basin and is close to that of Atlantic deepwater Cr (∼+0.5‰). This suggests that authigenic Cr in anoxic sediments may reliably reflect the first-order Cr isotope composition of deepwaters. For Peru Margin samples

  4. Sulfur and carbon cycling in organic-rich marine sediments

    Science.gov (United States)

    Martens, C. S.

    1985-01-01

    Nearshore, continental shelf, and slope sediments are important sites of microbially mediated carbon and sulfur cycling. Marine geochemists investigated the rates and mechanisms of cycling processes in these environments by chemical distribution studies, in situ rate measurements, and steady state kinetic modeling. Pore water chemical distributions, sulfate reduction rates, and sediment water chemical fluxes were used to describe cycling on a ten year time scale in a small, rapidly depositing coastal basin, Cape Lookout Bight, and at general sites on the upper continental slope off North Carolina, U.S.A. In combination with 210 Pb sediment accumulation rates, these data were used to establish quantitative carbon and sulfur budgets as well as the relative importance of sulfate reduction and methanogeneis as the last steps in the degradation of organic matter.

  5. Distribution of PAHs and the PAH-degrading bacteria in the deep-sea sediments of the high-latitude Arctic Ocean

    Science.gov (United States)

    Dong, C.; Bai, X.; Sheng, H.; Jiao, L.; Zhou, H.; Shao, Z.

    2015-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are common organic pollutants that can be transferred long distances and tend to accumulate in marine sediments. However, less is known regarding the distribution of PAHs and their natural bioattenuation in the open sea, especially the Arctic Ocean. In this report, sediment samples were collected at four sites from the Chukchi Plateau to the Makarov Basin in the summer of 2010. PAH compositions and total concentrations were examined with GC-MS. The concentrations of 16 EPA-priority PAHs varied from 2.0 to 41.6 ng g-1 dry weight and decreased with sediment depth and movement from the southern to the northern sites. Among the targeted PAHs, phenanthrene was relatively abundant in all sediments. The 16S rRNA gene of the total environmental DNA was analyzed with Illumina high-throughput sequencing (IHTS) to determine the diversity of bacteria involved in PAH degradation in situ. The potential degraders including Cycloclasticus, Pseudomonas, Halomonas, Pseudoalteromonas, Marinomonas, Bacillus, Dietzia, Colwellia, Acinetobacter, Alcanivorax, Salinisphaera and Shewanella, with Dietzia as the most abundant, occurred in all sediment samples. Meanwhile, enrichment with PAHs was initiated onboard and transferred to the laboratory for further enrichment and to obtain the degrading consortia. Most of the abovementioned bacteria in addition to Hahella, Oleispira, Oceanobacter and Hyphomonas occurred alternately as predominant members in the enrichment cultures from different sediments based on IHTS and PCR-DGGE analysis. To reconfirm their role in PAH degradation, 40 different bacteria were isolated and characterized, among which Cycloclasticus Pseudomonas showed the best degradation capability under low temperatures. Taken together, PAHs and PAH-degrading bacteria were widespread in the deep-sea sediments of the Arctic Ocean. We propose that bacteria of Cycloclasticus, Pseudomonas, Pseudoalteromonas, Halomonas, Marinomonas and Dietzia may

  6. Distribution of PAHs and the PAH-degrading bacteria in the deep-sea sediments of the high-latitude Arctic Ocean

    Directory of Open Access Journals (Sweden)

    C. Dong

    2014-09-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs are persistent organic pollutants, which can be transferred to a long distance and tend to accumulation in marine sediment. However, PAHs distribution and natural bioattenuation is less known in open sea, especially in the Arctic Ocean. In this report, sediment samples were collected at four sites from the Chukchi Plateau to Makarov Basin in the summer of 2010. PAH composition and total concentrations were examined with GC-MS, we found that the concentrations of 16 EPA-priority PAHs varied from 2.0 to 41.6 ng g−1 dry weight in total and decreased with sediment depths and as well as from the southern to northern sites. Among the targeted PAHs, phenanthrene was relatively abundant in all sediments. To learn the diversity of bacteria involved in PAHs degradation in situ, the 16S rRNA gene of the total environmental DNA was analyzed with Illumina high throughput sequencing (IHTS. In all the sediments, occurred the potential degraders including Cycloclasticus, Pseudomonas, Halomonas, Pseudoalteromonas, Marinomonas, Bacillus, Dietzia, Colwellia, Acinetobacter, Alcanivorax, Salinisphaera and Shewanella, with Dietzia as the most abundant. Meanwhile on board, enrichment with PAHs was initiated and repeated transfer in laboratory to obtain the degrading consortia. Most above mentioned bacteria in addition to Hahella, Oleispira, Oceanobacter and Hyphomonas, occurred alternately as a predominant member in enrichment cultures from different sediments, as revealed with IHTS and PCR-DGGE. To reconfirm their role in PAH degradation, 40 different bacteria were isolated and characterized, among which Cycloclasticus and Pseudomonas showed the best degradation capability under low temperature. Taken together, PAHs and PAH-degrading bacteria were widespread in the deep-sea sediments of the Arctic Ocean. We propose that bacteria of Cycloclasticus, Pseudomonas, Pseudoalteromonas, Halomonas, Marinomonas and Dietzia may play the

  7. Distribution of PAHs and the PAH-degrading bacteria in the deep-sea sediments of the high-latitude Arctic Ocean

    Science.gov (United States)

    Dong, C.; Bai, X.; Sheng, H.; Jiao, L.; Zhou, H.; Shao, Z.

    2014-09-01

    Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants, which can be transferred to a long distance and tend to accumulation in marine sediment. However, PAHs distribution and natural bioattenuation is less known in open sea, especially in the Arctic Ocean. In this report, sediment samples were collected at four sites from the Chukchi Plateau to Makarov Basin in the summer of 2010. PAH composition and total concentrations were examined with GC-MS, we found that the concentrations of 16 EPA-priority PAHs varied from 2.0 to 41.6 ng g-1 dry weight in total and decreased with sediment depths and as well as from the southern to northern sites. Among the targeted PAHs, phenanthrene was relatively abundant in all sediments. To learn the diversity of bacteria involved in PAHs degradation in situ, the 16S rRNA gene of the total environmental DNA was analyzed with Illumina high throughput sequencing (IHTS). In all the sediments, occurred the potential degraders including Cycloclasticus, Pseudomonas, Halomonas, Pseudoalteromonas, Marinomonas, Bacillus, Dietzia, Colwellia, Acinetobacter, Alcanivorax, Salinisphaera and Shewanella, with Dietzia as the most abundant. Meanwhile on board, enrichment with PAHs was initiated and repeated transfer in laboratory to obtain the degrading consortia. Most above mentioned bacteria in addition to Hahella, Oleispira, Oceanobacter and Hyphomonas, occurred alternately as a predominant member in enrichment cultures from different sediments, as revealed with IHTS and PCR-DGGE. To reconfirm their role in PAH degradation, 40 different bacteria were isolated and characterized, among which Cycloclasticus and Pseudomonas showed the best degradation capability under low temperature. Taken together, PAHs and PAH-degrading bacteria were widespread in the deep-sea sediments of the Arctic Ocean. We propose that bacteria of Cycloclasticus, Pseudomonas, Pseudoalteromonas, Halomonas, Marinomonas and Dietzia may play the most important role

  8. Marine biodegradation of crude oil in temperate and Arctic water samples.

    Science.gov (United States)

    Kristensen, Mette; Johnsen, Anders R; Christensen, Jan H

    2015-12-30

    Despite increased interest in marine oil exploration in the Arctic, little is known about the fate of Arctic offshore oil pollution. Therefore, in the present study, we examine the oil degradation potential for an Arctic site (Disko Bay, Greenland) and discuss this in relation to a temperate site (North Sea, Denmark). Biodegradation was assessed following exposure to Oseberg Blend crude oil (100 mg L(-1)) in microcosms. Changes in oil hydrocarbon fingerprints of polycyclic aromatic hydrocarbons (PAHs), alkyl-substituted PAHs, dibenzothiophenes, n-alkanes and alkyltoluenes were measured by gas chromatography-mass spectrometry (GC-MS). In the Disko Bay sample, the degradation order was n-alkanes>alkyltoluenes (para->meta->ortho-isomers)>PAHs and dibenzothiophenes, whereas, the degradation order in the North Sea samples was PAHs and dibenzothiophenes>alkyltoluenes>n-alkanes. These differences in degradation patterns significantly affect the environmental risk of oil spills and emphasise the need to consider the specific environmental conditions when conducting risk assessments of Arctic oil pollution.

  9. Trophic transfer of contaminants in a changing arctic marine food web: Cumberland Sound, Nunavut, Canada.

    Science.gov (United States)

    McKinney, Melissa A; McMeans, Bailey C; Tomy, Gregg T; Rosenberg, Bruno; Ferguson, Steven H; Morris, Adam; Muir, Derek C G; Fisk, Aaron T

    2012-09-18

    Contaminant dynamics in arctic marine food webs may be impacted by current climate-induced food web changes including increases in transient/subarctic species. We quantified food web organochlorine transfer in the Cumberland Sound (Nunavut, Canada) arctic marine food web in the presence of transient species using species-specific biomagnification factors (BMFs), trophic magnification factors (TMFs), and a multifactor model that included δ(15)N-derived trophic position and species habitat range (transient versus resident), and also considered δ(13)C-derived carbon source, thermoregulatory group, and season. Transient/subarctic species relative to residents had higher prey-to-predator BMFs of biomagnifying contaminants (1.4 to 62 for harp seal, Greenland shark, and narwhal versus 1.1 to 20 for ringed seal, arctic skate, and beluga whale, respectively). For contaminants that biomagnified in a transient-and-resident food web and a resident-only food web scenario, TMFs were higher in the former (2.3 to 10.1) versus the latter (1.7 to 4.0). Transient/subarctic species have higher tissue contaminant levels and greater BMFs likely due to higher energetic requirements associated with long-distance movements or consumption of more contaminated prey in regions outside of Cumberland Sound. These results demonstrate that, in addition to climate change-related long-range transport/deposition/revolatilization changes, increasing numbers of transient/subarctic animals may alter food web contaminant dynamics.

  10. Importance of Marine-Derived Nutrients Supplied by Planktivorous Seabirds to High Arctic Tundra Plant Communities

    Science.gov (United States)

    Zwolicki, Adrian; Zmudczyńska-Skarbek, Katarzyna; Richard, Pierre; Stempniewicz, Lech

    2016-01-01

    We studied the relative importance of several environmental factors for tundra plant communities in five locations across Svalbard (High Arctic) that differed in geographical location, oceanographic and climatic influence, and soil characteristics. The amount of marine-derived nitrogen in the soil supplied by seabirds was locally the most important of the studied environmental factors influencing the tundra plant community. We found a strong positive correlation between δ15N isotopic values and total N content in the soil, confirming the fundamental role of marine-derived matter to the generally nutrient-poor Arctic tundra ecosystem. We also recorded a strong correlation between the δ15N values of soil and of the tissues of vascular plants and mosses, but not of lichens. The relationship between soil δ15N values and vascular plant cover was linear. In the case of mosses, the percentage ground cover reached maximum around a soil δ 15N value of 8‰, as did plant community diversity. This soil δ15N value clearly separated the occurrence of plants with low nitrogen tolerance (e.g. Salix polaris) from those predominating on high N content soils (e.g. Cerastium arcticum, Poa alpina). Large colonies of planktivorous little auks have a great influence on Arctic tundra vegetation, either through enhancing plant abundance or in shaping plant community composition at a local scale. PMID:27149113

  11. Importance of Marine-Derived Nutrients Supplied by Planktivorous Seabirds to High Arctic Tundra Plant Communities.

    Directory of Open Access Journals (Sweden)

    Adrian Zwolicki

    Full Text Available We studied the relative importance of several environmental factors for tundra plant communities in five locations across Svalbard (High Arctic that differed in geographical location, oceanographic and climatic influence, and soil characteristics. The amount of marine-derived nitrogen in the soil supplied by seabirds was locally the most important of the studied environmental factors influencing the tundra plant community. We found a strong positive correlation between δ15N isotopic values and total N content in the soil, confirming the fundamental role of marine-derived matter to the generally nutrient-poor Arctic tundra ecosystem. We also recorded a strong correlation between the δ15N values of soil and of the tissues of vascular plants and mosses, but not of lichens. The relationship between soil δ15N values and vascular plant cover was linear. In the case of mosses, the percentage ground cover reached maximum around a soil δ 15N value of 8‰, as did plant community diversity. This soil δ15N value clearly separated the occurrence of plants with low nitrogen tolerance (e.g. Salix polaris from those predominating on high N content soils (e.g. Cerastium arcticum, Poa alpina. Large colonies of planktivorous little auks have a great influence on Arctic tundra vegetation, either through enhancing plant abundance or in shaping plant community composition at a local scale.

  12. Importance of Marine-Derived Nutrients Supplied by Planktivorous Seabirds to High Arctic Tundra Plant Communities.

    Science.gov (United States)

    Zwolicki, Adrian; Zmudczyńska-Skarbek, Katarzyna; Richard, Pierre; Stempniewicz, Lech

    2016-01-01

    We studied the relative importance of several environmental factors for tundra plant communities in five locations across Svalbard (High Arctic) that differed in geographical location, oceanographic and climatic influence, and soil characteristics. The amount of marine-derived nitrogen in the soil supplied by seabirds was locally the most important of the studied environmental factors influencing the tundra plant community. We found a strong positive correlation between δ15N isotopic values and total N content in the soil, confirming the fundamental role of marine-derived matter to the generally nutrient-poor Arctic tundra ecosystem. We also recorded a strong correlation between the δ15N values of soil and of the tissues of vascular plants and mosses, but not of lichens. The relationship between soil δ15N values and vascular plant cover was linear. In the case of mosses, the percentage ground cover reached maximum around a soil δ 15N value of 8‰, as did plant community diversity. This soil δ15N value clearly separated the occurrence of plants with low nitrogen tolerance (e.g. Salix polaris) from those predominating on high N content soils (e.g. Cerastium arcticum, Poa alpina). Large colonies of planktivorous little auks have a great influence on Arctic tundra vegetation, either through enhancing plant abundance or in shaping plant community composition at a local scale. PMID:27149113

  13. Trophic transfer of contaminants in a changing arctic marine food web: Cumberland Sound, Nunavut, Canada.

    Science.gov (United States)

    McKinney, Melissa A; McMeans, Bailey C; Tomy, Gregg T; Rosenberg, Bruno; Ferguson, Steven H; Morris, Adam; Muir, Derek C G; Fisk, Aaron T

    2012-09-18

    Contaminant dynamics in arctic marine food webs may be impacted by current climate-induced food web changes including increases in transient/subarctic species. We quantified food web organochlorine transfer in the Cumberland Sound (Nunavut, Canada) arctic marine food web in the presence of transient species using species-specific biomagnification factors (BMFs), trophic magnification factors (TMFs), and a multifactor model that included δ(15)N-derived trophic position and species habitat range (transient versus resident), and also considered δ(13)C-derived carbon source, thermoregulatory group, and season. Transient/subarctic species relative to residents had higher prey-to-predator BMFs of biomagnifying contaminants (1.4 to 62 for harp seal, Greenland shark, and narwhal versus 1.1 to 20 for ringed seal, arctic skate, and beluga whale, respectively). For contaminants that biomagnified in a transient-and-resident food web and a resident-only food web scenario, TMFs were higher in the former (2.3 to 10.1) versus the latter (1.7 to 4.0). Transient/subarctic species have higher tissue contaminant levels and greater BMFs likely due to higher energetic requirements associated with long-distance movements or consumption of more contaminated prey in regions outside of Cumberland Sound. These results demonstrate that, in addition to climate change-related long-range transport/deposition/revolatilization changes, increasing numbers of transient/subarctic animals may alter food web contaminant dynamics. PMID:22957980

  14. Chemometric Analysis for Pollution Source Assessment of Harbour Sediments in Arctic Locations

    DEFF Research Database (Denmark)

    Pedersen, Kristine B.; Lejon, Tore; Jensen, Pernille Erland;

    2015-01-01

    Pollution levels, pollutant distribution and potential source assessments based on multivariate analysis (chemometrics) were made for harbour sediments from two Arctic locations; Hammerfest in Norway and Sisimiut in Greenland. High levels of heavy metals were detected in addition to organic...... pollutants. Preliminary assessments based on principal component analysis (PCA) revealed different sources and pollutant distribution in the sediments of the two harbours. Tributyltin (TBT) was, however, found to originate from point source(s), and the highest concentrations of TBT in both harbours were...... indicated relation primarily to German, Russian and American mixtures in Hammerfest; and American, Russian and Japanese mixtures in Sisimiut. PCA was shown to be an important tool for identifying pollutant sources and differences in pollutant composition in relation to sediment characteristics....

  15. Sedimentary processes in High Arctic lakes (Cape Bounty, Melville Island, Canada): What do sediments really record?

    Science.gov (United States)

    Normandeau, Alexandre; Lamoureux, Scott; Lajeunesse, Patrick; Francus, Pierre

    2016-04-01

    Lacustrine sedimentary sequences can hold a substantial amount of information regarding paleoenvironments, hydroclimate variability and extreme events, providing critical insights into past climate change. The study of lacustrine sediments is often limited to the analysis of sediment cores from which past changes are inferred. However, studies have provided evidence that the accumulation of sediments in lacustrine basins and their distribution can be affected by a wide range of internal and external forcing mechanisms. It is therefore crucial to have a good knowledge of the factors controlling the transport and distribution of sediments in lakes prior to investigating paleoenvironmental archives. To address this knowledge gap, the Cape Bounty Arctic Watershed Observatory (CBAWO), located on southern Melville Island in the Canadian High Arctic, was initiated in 2003 as a long term monitoring site with the aim of understanding the controls over sediment transport within similar paired watersheds and lakes. The East and West lakes have been monitored each year since 2003 to document the role of hydro-climate variability on water column processes and sediment deposition. Moorings recording water electrical conductivity, temperature, density, dissolved oxygen and turbidity, as well as sediment traps were deployed during the active hydrological period (generally May-July). These data were analyzed in combination with hydrological and climatic data from the watersheds. Additionally, a high-resolution bathymetric and sub-bottom survey was completed in 2015 and allowed imaging the lake floor and sub-surface in great detail. This combination of process and lake morphological data are unique in the Arctic. The morphostratigraphic analysis reveals two highly disturbed lake floors, being widely affected by subaqueous mass movements that were triggered during the last 2000 years. Backscatter intensity maps and the presence of bedforms on each delta foresets indicate that

  16. Evolution of Arctic Ocean temperatures and fate of marine gas hydrates under global warming

    Science.gov (United States)

    Biastoch, Arne; Treude, Tina; Roth, Christina; Lüpke, Lars; Burwicz, Ewa; Park, Wonsun; Latif, Mojib; Böning, Claus; Madec, Gurvan; Wallmann, Klaus

    2010-05-01

    Several thousand gigatons of methane hydrates are estimated to be locked up in sediments of continental margins. Their stability is controlled by low temperature - high pressure conditions. Warming of the oceans could destabilize large amounts of hydrates along upper margins causing the release of methane, a greenhouse gas 30 times more potent per molecule than CO2, into the hydrosphere and atmosphere. The Arctic has considerably warmed during the recent decade, as witnessed by the rapid sea ice melt, and climate models project an acceleration of Arctic climate change in the future, if global greenhouse gas emissions continue to increase. Stabilized by year-round cold temperatures Arctic methane hydrates are deposited at shallow water depth close to shelf edges. Low pressure and the vicinity to the sea-air interface make Arctic gas hydrates more sensitive to atmospheric warming and associated changes in the temperature regime of the upper water masses compared to other oceans. We analyse bottom water temperatures and their future evolution projected by a climate model by applying a business as usual scenario and estimate their impact on the distribution of gas hydrate stability zones. Shallow gas hydrates are most strongly affected in areas affected by Atlantic inflow and could result in a significant impact on the methane distribution of the atmosphere, enhancing global warming

  17. Zinc Isotope Ratios as Indicators of Diet and Trophic Level in Arctic Marine Mammals.

    Science.gov (United States)

    Jaouen, Klervia; Szpak, Paul; Richards, Michael P

    2016-01-01

    Carbon and nitrogen stable isotope ratios of bone collagen are an established method for dietary reconstruction, but this method is limited by the protein preservation. Zinc (Zn) is found in bioapatite and the isotopic compositions of this element constitute a very promising dietary indicator. The extent of fractionation of Zn isotopes in marine environments, however, remains unknown. We report here on the measurement of zinc, carbon and nitrogen isotopes in 47 marine mammals from the archaeological site of Arvik in the Canadian Arctic. We undertook this study to test and demonstrate the utility of Zn isotopes in recent mammal bone minerals as a dietary indicator by comparing them to other isotopic dietary tracers. We found a correlation between δ66Zn values and trophic level for most species, with the exception of walruses, which may be caused by their large seasonal movements. δ6Zn values can therefore be used as a dietary indicator in marine ecosystems for both modern and recent mammals.

  18. Bacterial activities driving arsenic speciation and solubility in marine sediments

    Science.gov (United States)

    Battaglia-Brunet, F.; Seby, F.; Crouzet, C.; Joulian, C.; Mamindy-Pajany, Y.; Guezennec, A. G.; Hurel, C.; Marmier, N.; Bataillard, P.

    2012-04-01

    Harbour and marina sediments represent particular environments, with high concentrations in organic carbon and pollutants. Over 50 million m3 of marine sediments are dredged every year in French maritime and commercial ports, to maintain the water depth suitable for navigation, and the most part of them is discharged in deeper sea zones. The present study aimed to elucidate, using a range of complementary approaches, the influence of bacterial activity on arsenic speciation and mobility in marina sediments. Two sites were considered: L'Estaque, impacted by metallurgical activities and by the commercial port of Marseille, and St-Mandrier, less polluted, affected by classical chemical pollutants associated to professional and recreational boating. Arsenic concentration was noticeably higher in l'Estaque sediment (200-350 mg/kg) than in St-Mandrier sediment (15-50 mg/kg). In the solid phases, As(III) was the dominant species in L'Estaque sediment, whereas As(V) was the main form in St Mandrier sediment. At both sites, arsenic was the major trace element detected in interstitial water. Free sulfide and thio-arsenic complexes were detected in the interstitial water of l'Estaque sediment, suggesting a role of sulfate-reduction bacterial activity on arsenic solubility. Anaerobic microcosm experiments confirmed this hypothesis, as stimulation of sulfate-reduction induced a dramatic increase of arsenic concentration in the liquid phase, linked to the formation of soluble thio-arsenic complexes. Nevertheless, microcosms performed in aerobic conditions showed that bacterial activity globally decreased the transfer of arsenic from the sediment toward the overlying water. A red-brown fine layer developed at the sediment-water interface. Altogether, these results suggest that the sediment-water interface zone and the close transition area between aerobic and anaerobic conditions host intense biogeochemical reactions involving As, Fe and S species. These reactions most probably

  19. Detrital zircons (U-Pb and Lu-Hf) and host hemipelagic sediments (Pb-Sr-Nd-Os) from the Polar Arctic

    Science.gov (United States)

    Kapitonov, Igor; Belyatsky, Boris; Petrov, Eugeny; Sergeev, Sergey

    2015-04-01

    . However, a direct resemblance to the Permo-Triassic and Jurassic sandstones of coastal areas of the Arctic, we also do not see. Another factor in the formation of deep marine sediments is fluvial transference. The total input of the Arctic rivers reaches about 1x106 tonnes per year. When comparing the characteristics of detrital zircons of different river systems, we see that the similar is the distribution of zircon ages from the deposits of the Lena, Yenisei and Yana-Indigirka. Given that the Laptev Sea is the main source of «dirty» sea ice, carried by Transpolar Drift in the central part of the Arctic Ocean, detrital zircons from sediments of Lena river, which is characterized by the highest among Arctic rivers discharge, apparently, ensure the formation of the heavy fraction of hemipelagic mud in a large deep-water area of the Arctic Ocean, including the polar region. The observed variations in local distribution of zircon ages in the studied sampling points do not exclude the presence of local material, but to determine its share and establish with certainty the composition further research is required.

  20. Marine fungi isolated from Chilean fjord sediments can degrade oxytetracycline.

    Science.gov (United States)

    Ahumada-Rudolph, R; Novoa, V; Sáez, K; Martínez, M; Rudolph, A; Torres-Diaz, C; Becerra, J

    2016-08-01

    Salmon farming is the main economic activity in the fjords area of Southern Chile. This activity requires the use of antibiotics, such as oxytetracycline, for the control and prevention of diseases, which have a negative impact on the environment. We analyzed the abilities of endemic marine fungi to biodegrade oxytetracycline, an antibiotic used extensively in fish farming. We isolated marine fungi strains from sediment samples obtained from an area of fish farming activity. The five isolated strains showed an activity on oxytetracycline and were identified as Trichoderma harzianum, Trichoderma deliquescens, Penicillium crustosum, Rhodotorula mucilaginosa, and Talaromyces atroroseus by a scanning electron microscopy and characterized by molecular techniques. Results showed significant degradation in the concentration of oxytetracycline at the first 2 days of treatment for all strains analyzed. At 21 days of treatment, the concentration of oxytetracycline was decreased 92 % by T. harzianum, 85 % by T. deliquescens, 83 % by P. crustosum, 73 % by R. mucilaginosa, and 72 % by T. atroroseus, all of which were significantly higher than the controls. Given these results, we propose that fungal strains isolated from marine sediments may be useful tools for biodegradation of antibiotics, such as oxytetracycline, in the salmon industry. PMID:27418075

  1. Provenance analysis of central Arctic Ocean sediments: Implications for circum-Arctic ice sheet dynamics and ocean circulation during Late Pleistocene

    Science.gov (United States)

    Kaparulina, Ekaterina; Strand, Kari; Lunkka, Juha Pekka

    2016-09-01

    Mineralogical and geochemical data generated from the well referred shallow core 96/12-1pc on the Lomonosov Ridge, central Arctic Ocean was used to evaluate ice transport from the circum-Arctic sources and variability in sediment drainage and provenance changes. In this study heavy minerals in central Arctic sediments were used to determine those most prominent provenance areas and their changes related to the Late Pleistocene history of glaciations in the Arctic. Provenance changes were then used to infer variations in the paleoceanographic environment of the central Arctic Ocean, such as variations in the distribution of sea ice, icebergs controlled by the Arctic Ocean circulation. Four critical end-members including Victoria and Banks Islands, the Putorana Plateau, the Anabar Shield, and the Verkhoyansk Fold Belt were identified from the Amerasian and Eurasian source areas, and their proportional contributions were estimated in relation to Late Pleistocene ice sheet dynamics and ocean circulation. The results show changes in transport pathways and source areas within two examined transitions MIS6-5 and MIS4-3. The main source for material during MIS6-5 transition was Amerasian margin due to the high dolomite content in the studied section of sediments inferring strong Beaufort Gyre (BG) and Transpolar Drift (TPD) transport for this material. IRD material during late the MIS6 to 5 deglacial event was from terrigenous input through from the MacKenzie route Banks/Victoria Islands then transported as far as the Lomonosov Ridge area. The transition, MIS4-3 in comparison with MIS6-5, shows a clear shift in source areas, reflected in a different mineralogical composition of sediments, supplied from the Eurasian margin, such as the Anabar Shield, the Putorana Plateau and the Verkhoyansk Fold Belt during active decay of the Barents-Kara Ice Sheet presumable associated with an ice-dammed lake outburst then triggered by a strong TPD over the central Arctic. These two

  2. Orchomenella pinguis (amphipoda)-a possible species for heavy metal biomonitoring of marine sediments

    Institute of Scientific and Technical Information of China (English)

    Lis Bach; Laura Ferguson; Vilhelm Feltelius; Jens Sondergaard

    2014-01-01

    Objective:To evaluate the potential local benthic biomonitor organism, Orchomenella pinguis (O. pinguis), for mining contamination by addressing accumulation and toxicity of mining related metals in this arctic marine amphipod. Methods:A toxicity study exposed O. pinguis to four commonly occurring heavy metals (Cd, Cu, Zn and Pb) associated to the mining industry in Greenland using:1) a 5-day water-only bioassay;2) a water-only bioassay evaluating the response between metal accumulation in O. pinguis and metal concentrations in water during a 5-day period;and finally 3) a sediment bioassay evaluating the response between metal accumulation in O. pinguis and metal concentrations in sediment as a function of time during a 20-day period using different mixtures of mining-contaminated sediments. Results:LC50 values for the four metals were 2.8, 5.4, 10.4 and 21.4 µmol/L, for Cu, Cd, Pb and Zn, respectively, with corresponding modelled metal concentrations of 3.4, 1.0, 11.1 and 6.1 µmol/g dry weight. During the sediment exposure experiments, a similar concentration of Zn did not induce lethal effects at the same level. Conclusions: This study demonstrates that the appliance of metal organism concentrations as an estimate of effects is not a sufficient biomonitor of environmental effects. The organism may sequester metals into cellular compartments thus rendering the metals inert for toxic effects. More studies are needed to investigate effects of metal bioavailability. Additional biomarkers such as effects on functional responses e.g. feeding and burial behavior or effects on reproductive success are suggested in order enhance to the ecological significance.

  3. Orchomenella pinguis (amphipoda-a possible species for heavy metal biomonitoring of marine sediments

    Directory of Open Access Journals (Sweden)

    Lis Bach

    2014-02-01

    Full Text Available Objective: To evaluate the potential local benthic biomonitor organism, Orchomenella pinguis (O. pinguis, for mining contamination by addressing accumulation and toxicity of mining related metals in this arctic marine amphipod. Methods: A toxicity study exposed O. pinguis to four commonly occurring heavy metals (Cd, Cu, Zn and Pb associated to the mining industry in Greenland using: 1 a 5-day water-only bioassay; 2 a water-only bioassay evaluating the response between metal accumulation in O. pinguis and metal concentrations in water during a 5-day period; and finally 3 a sediment bioassay evaluating the response between metal accumulation in O. pinguis and metal concentrations in sediment as a function of time during a 20-day period using different mixtures of mining-contaminated sediments. Results: LC50 values for the four metals were 2.8, 5.4, 10.4 and 21.4 µmol/L, for Cu, Cd, Pb and Zn, respectively, with corresponding modelled metal concentrations of 3.4, 1.0, 11.1 and 6.1 µmol/g dry weight. During the sediment exposure experiments, a similar concentration of Zn did not induce lethal effects at the same level. Conclusions: This study demonstrates that the appliance of metal organism concentrations as an estimate of effects is not a sufficient biomonitor of environmental effects. The organism may sequester metals into cellular compartments thus rendering the metals inert for toxic effects. More studies are needed to investigate effects of metal bioavailability. Additional biomarkers such as effects on functional responses e.g. feeding and burial behavior or effects on reproductive success are suggested in order enhance to the ecological significance.

  4. Defining ecospace of Arctic marine food webs using a novel quantitative approach

    Science.gov (United States)

    Gale, M.; Loseto, L. L.

    2011-12-01

    The Arctic is currently facing unprecedented change with developmental, physical and climatological changes. Food webs within the marine Arctic environment are highly susceptible to anthropogenic stressors and have thus far been understudied. Stable isotopes, in conjunction with a novel set of metrics, may provide a framework that allows us to understand which areas of the Arctic are most vulnerable to change. The objective of this study was to use linear distance metrics applied to stable isotopes to a) define and quantify four Arctic marine food webs in ecospace; b) enable quantifiable comparisons among the four food webs and with other ecosystems; and, c) evaluate vulnerability of the four food webs to anthropogenic stressors such as climate change. The areas studied were Hudson Bay, Beaufort Sea, Lancaster Sound and North Water Polynya. Each region was selected based on the abundance of previous research and published and available stable isotope data in peer-review literature. We selected species to cover trophic levels ranging from particulate matter to polar bears with consideration of pelagic, benthic and ice-associated energy pathways. We interpret higher diversity in baseline carbon energy as signifying higher stability in food web structure. Based on this, the Beaufort Sea food web had the highest stability; the Beaufort Sea food web occupied the largest isotopic niche space and was supported by multiple carbon sources. Areas with top-down control system, such as Lancaster Sound and North Water Polynya, would be the first to experience an increase in trophic redundancy and possible hardships from external stressors, as they have fewer basal carbon sources and greater numbers of mid-high level consumers. We conclude that a diverse carbon energy based ecosystem such as the Beaufort Sea and Hudson Bay regions are more resilient to change than a top down control system.

  5. Psychrotrophic lipase producers from Arctic soil and sediment samples.

    Science.gov (United States)

    Rasol, R; Rashidah, A R; Nazuha, R Siti Nur; Smykla, J; Maznah, W O Wan; Alias, S A

    2014-01-01

    Culturable microorganisms were successfully isolated from soil and sediment samples collected in 2011 on the northern coast of Hornsund, West Spitsbergen. A total of 63 single colony isolates from three sampling sites obtained were subjected to temperature dependence study to assess whether they are obligate psychrophilic or psychrotrophic strains. From initial temperature screening, only 53 psychrotrophic isolates were selected that are capable of growing between 4-28 degrees C. The rest that were capable of tolerating higher temperatures up to 37 degrees C were not included in this study. These isolates were chosen for lipase enzyme screening confirmation with the standard plate assay of olive oil and fluorescent dye Rhodamine B. Six lipase positive isolates were also subjected for subsequent lipase enzyme plate screening on tributyrin, triolein, olive oil and palm oil agar. Lipase production by these six isolates was further assayed by using colorimetric method with palm oil and olive oil as the substrate. These isolates with promising lipase activity ranging from 20 U/ml up to 160 U/ml on palm oil and olive oil substrate were successfully identified. Molecular identification by using 16S rRNA revealed that five out of six isolates were Gram-negative Proteobacteria and the other one was a Gram-positive Actinobacteria. PMID:25033666

  6. Quantitative and phylogenetic study of the Deep Sea Archaeal Group in sediments of the arctic mid-ocean spreading ridge

    Directory of Open Access Journals (Sweden)

    Steffen Leth eJørgensen

    2013-10-01

    Full Text Available In marine sediments archaea often constitute a considerable part of the microbial community, of which the Deep Sea Archaeal Group (DSAG is one of the most predominant. Despite their high abundance no members from this archaeal group have so far been characterized and thus their metabolism is unknown. Here we show that the relative abundance of DSAG marker genes can be correlated with geochemical parameters, allowing prediction of both the potential electron donors and acceptors of these organisms. We estimated the abundance of 16S rRNA genes from Archaea, Bacteria and DSAG in 52 sediment horizons from two cores collected at the slow-spreading Arctic Mid-Ocean Ridge, using qPCR. The results indicate that members of the DSAG make up the entire archaeal population in certain horizons and constitute up to ~ 50% of the total microbial community. The quantitative data were correlated to 30 different geophysical and geochemical parameters obtained from the same sediment horizons. We observed a significant correlation between the relative abundance of DSAG 16S rRNA genes and the content of organic carbon (p < 0.0001. Further, significant co-variation with iron oxide, and dissolved iron and manganese (all p < 0.0000, indicated a direct or indirect link to iron and manganese cycling. Neither of these parameters correlated with the relative abundance of archaeal or bacterial 16S rRNA genes, nor did any other major electron donor or acceptor measured. Phylogenetic analysis of DSAG 16S rRNA gene sequences reveals three monophyletic lineages with no apparent habitat-specific distribution. In this study we support the hypothesis that members of the DSAG are tightly linked to the content of organic carbon and directly or indirectly involved in the cycling of iron and/or manganese compounds. Further, we provide a molecular tool to assess their abundance in environmental samples and enrichment cultures.

  7. Phylogenetic analysis of the bacterial communities in marine sediments.

    OpenAIRE

    Gray, J P; Herwig, R P

    1996-01-01

    For the phylogenetic analysis of microbial communities present in environmental samples microbial DNA can be extracted from the sample, 16S rDNA can be amplified with suitable primers and the PCR, and clonal libraries can be constructed. We report a protocol that can be used for efficient cell lysis and recovery of DNA from marine sediments. Key steps in this procedure include the use of a bead mill homogenizer for matrix disruption and uniform cell lysis and then purification of the released...

  8. The Arctic Ocean marine carbon cycle: evaluation of air-sea CO2 exchanges, ocean acidification impacts and potential feedbacks

    Directory of Open Access Journals (Sweden)

    J. T. Mathis

    2009-07-01

    Full Text Available At present, although seasonal sea-ice cover mitigates atmosphere-ocean gas exchange, the Arctic Ocean takes up carbon dioxide (CO2 on the order of −65 to −175 Tg C year−1, contributing 5–14% to the global balance of CO2 sinks and sources. Because of this, the Arctic Ocean is an important influence on the global carbon cycle, with the marine carbon cycle and atmosphere-ocean CO2 exchanges sensitive to Arctic Ocean and global climate change feedbacks. In the near-term, further sea-ice loss and increases in phytoplankton growth rates are expected to increase the uptake of CO2 by Arctic surface waters, although mitigated somewhat by surface warming in the Arctic. Thus, the capacity of the Arctic Ocean to uptake CO2 is expected to alter in response to environmental changes driven largely by climate. These changes are likely to continue to modify the physics, biogeochemistry, and ecology of the Arctic Ocean in ways that are not yet fully understood. In surface waters, sea-ice melt, river runoff, cooling and uptake of CO2 through air-sea gas exchange combine to decrease the calcium carbonate (CaCO3 mineral saturation states (Ω of seawater that is counteracted by seasonal phytoplankton primary production (PP. Biological processes drive divergent trajectories for Ω in surface and subsurface waters of Arctic shelves with subsurface water experiencing undersaturation with respect to aragonite and calcite. Thus, in response to increased sea-ice loss, warming and enhanced phytoplankton PP, the benthic ecosystem of the Arctic shelves are expected to be negatively impacted by the biological amplification of ocean acidification. This in turn reduces the ability of many species to produce CaCO3 shells or tests with profound implications for Arctic marine ecosystems.

  9. Identifying nitrogen limitations to organic sediments accumulation in various vegetation types of arctic tundra (Hornsund, Svalbard)

    Science.gov (United States)

    Skrzypek, G.; Wojtuń, B.; Hua, Q.; Richter, D.; Jakubas, D.; Wojczulanis-Jakubas, K.; Samecka-Cymerman, A.

    2015-12-01

    Arctic and subarctic regions play important roles in the global carbon balance. However, nitrogen (N) deficiency is a major constraint for organic carbon sequestration in the High Arctic. Hence, the identification of the relative contributions from different N-sources is critical for understanding the constraints that limit tundra growth. The stable nitrogen composition of the three main N-sources and numerous plants were analyzed in ten tundra types in the Fuglebekken catchment (Hornsund Fjord, Svalbard, 77°N 15°E). The percentage of the total tundra N-pool provided by seabirds' feces (colonially breeding, planktivorous Alle alle), ranged from 0-21% in Patterned-ground tundra to 100% in Ornithocoprophilous tundra. The total N-pool utilized by tundra plants in the studied catchment was built in 36% by birds, 38% by atmospheric deposition, and 26% by N2-fixation. The results clearly show that N-pool in the tundra is significantly supplemented by nesting seabirds. Thus, if they experienced substantial negative environmental pressure associated with climate change, it would adversely influence the tundra N-budget [1]. The growth rates and the sediment thickness (climatic conditions but also by birds' contribution to the tundra N-pool. [1] Skrzypek G, Wojtuń B, Richter D, Jakubas D, Wojczulanis-Jakubas K, Samecka-Cymerman A, 2015. Diversification of nitrogen sources in various tundra vegetation types in the high Arctic. PLoS ONE (in review).

  10. Magnet-Facilitated Selection of Electrogenic Bacteria from Marine Sediment

    Directory of Open Access Journals (Sweden)

    Larisa Kiseleva

    2015-01-01

    Full Text Available Some bacteria can carry out anaerobic respiration by depositing electrons on external materials, such as electrodes, thereby creating an electrical current. Into the anode chamber of microbial fuel cells (MFCs having abiotic air-cathodes we inoculated microorganisms cultured from a magnetic particle-enriched portion of a marine tidal sediment, reasoning that since some external electron acceptors are ferromagnetic, electrogenic bacteria should be found in their vicinity. Two MFCs, one inoculated with a mixed bacterial culture and the other with an axenic culture of a helical bacterium isolated from the magnetic particle enrichment, termed strain HJ, were operated for 65 d. Both MFCs produced power, with production from the mixed culture MFC exceeding that of strain HJ. Strain HJ was identified as a Thalassospira sp. by transmission electron microscopic analysis and 16S rRNA gene comparisons. An MFC inoculated with strain HJ and operated in open circuit produced 47% and 57% of the maximal power produced from MFCs inoculated with the known electrogen Geobacter daltonii and the magnetotactic bacterium Desulfamplus magnetomortis, respectively. Further investigation will be needed to determine whether bacterial populations associated with magnetic particles within marine sediments are enriched for electrogens.

  11. A biomarker record of Lake El'gygytgyn, Far East Russian Arctic: investigating sources of organic matter and carbon cycling during marine isotope stages 1–3

    Directory of Open Access Journals (Sweden)

    A. R. Holland

    2013-01-01

    Full Text Available Arctic paleoenvironmental archives serve as sensitive recorders of past climate change. Lake El'gygytgyn (Far East Russian Arctic is a high-latitude crater impact lake that contains a continuous sediment record influenced by neither glaciation nor glacial erosion since the time of impact 3.58 Ma ago. Prior research on sediments collected from Lake El'gygytgyn suggest times of permanent ice cover and anoxia corresponding to global glacial intervals, during which the sediments are laminated and are characterized by the co-occurrence of high total organic carbon, microscopic magnetite grains that show etching and dissolution, and negative excursions in bulk sediment organic matter carbon isotope (δ13C values. Here we investigate the abundance and carbon isotopic composition of lipid biomarkers recovered from Lake El'gygytgyn sediments spanning marine isotope stages 1–3 to identify key sources of organic matter (OM to lake sediments, to establish which OM sources drive the negative δ13C excursion exhibited by bulk sediment OM, and to explore if there are molecular and isotopic signatures of anoxia in the lake during glaciation. We find that during marine isotope stages 1–3, direct evidence for water column anoxia is lacking. A ~4‰ negative excursion in bulk sediment δ13C values during the Local Last Glacial Maximum (LLGM is accompanied by more protracted, higher magnitude negative excursions in n-alkanoic acid and n-alkanol δ13C values that begin 20 kyr in advance of the LLGM. In contrast, n-alkanes and the C30 n-alkanoic acid do not exhibit a negative δ13C excursion at this time. Our results indicate that the C24, C26 and C28 n-alkanoic acids do not derive entirely from terrestrial OM sources, while the C30 n-alkanoic acid at Lake El'gygytgyn is a robust indicator of terrestrial OM contributions. Overall, our results strongly support the presence of a nutrient-poor water column, which is mostly isolated from atmospheric carbon dioxide

  12. [PATTERNS IN CIRCULATION AND TRANSMISSION OF MARINE BIRD PARASITES IN HIGH ARCTIC: A CASE OF ACANTHOCEPHALAN POLYMORPHUS PHIPPSI (PALAEACANTHOCEPHALA, POLYMORPHIDAE)].

    Science.gov (United States)

    Galaktionov, K V; Atrashkevich, G I

    2015-01-01

    This study, based on the materials on parasitic infection of marine birds and invertebrates in Frantz Josef Land (FJL) collected in 1991-1993, focussed on the acanthocephalan Polymorphus phippsi. We identified this parasite, confirmed its species status and analysed its circulation and transmission patterns in high Arctic. The causes of its erroneous identification as P. minutus in several studies were also examined. In contrast to P. minutus, the transmission of P. phippsi is realized in marine coastal ecosystems. Its' main intermediate host in the Arctic is the amphipod Gammarus (Lagunogammarus) setosus, commonin coastal. areas of the shelf zone throughout the Arctic basin. P. phippsi population in FJL and the entire European Arctic is on the whole maintained by a single obligate final host, the common eider Somateria mollissima. Prevalence (P) of P. phippsi in this bird reached 100 %, with the maximal infection intensity (IImax) of 1188 and the mean abundance (MA) of 492.1. Other species of birds found to be infected with P. phippsi (Arctic turn, black guillemot, purple sandpiper and several gulls) are facultative and/or eliminative hosts. The most heavily infected birds were Arctic terns (P = 72.7%, IImax = 227, MA = = 47.1), which contained single mature acanthocephalans. For one of the FJL regions, infections flows of P. phippsi through various host categories were calculated. Involvement of birds unrelated to the common eider into the circulation of P. phippsi is facilitated by their feeding character in the Arctic. While coastal crustaceans are abundant, fish food is relatively scarce (polar cod, snailfishes), and so amphipods make up a considerable part of the diet of marine birds in FJL, if not most of it, as for instance in case of Arctic tern. This promotes an easy entry of the larvae of crustaceans-parasitizing helminthes (cestodes and acanthocephalans, including cystacanths P. phippsi) into non-specific hosts and opens broad colonization possibilities

  13. Low Density of Top Predators (Seabirds and Marine Mammals in the High Arctic Pack Ice

    Directory of Open Access Journals (Sweden)

    Claude R. Joiris

    2016-01-01

    Full Text Available The at-sea distribution of top predators, seabirds and marine mammals, was determined in the high Arctic pack ice on board the icebreaker RV Polarstern in July to September 2014. In total, 1,620 transect counts were realised, lasting 30 min each. The five most numerous seabird species represented 74% of the total of 15,150 individuals registered: kittiwake Rissa tridactyla, fulmar Fulmarus glacialis, puffin Fratercula arctica, Ross’s gull Rhodostethia rosea, and little auk Alle alle. Eight cetacean species were tallied for a total of 330 individuals, mainly white-beaked dolphin Lagenorhynchus albirostris and fin whale Balaenoptera physalus. Five pinniped species were represented by a total of 55 individuals and the polar bear Ursus maritimus was represented by 12 individuals. Four main geographical zones were identified: from Tromsø to the outer marginal ice zone (OMIZ, the Arctic pack ice (close pack ice, CPI, the end of Lomonosov Ridge off Siberia, and the route off Siberia and northern Norway. Important differences were detected between zones, both in species composition and in individual abundance. Low numbers of species and high proportion of individuals for some of them can be considered to reflect very low biodiversity. Numbers encountered in zones 2 to 4 were very low in comparison with other European Arctic seas. The observed differences showed strong patterns.

  14. Comparison between summertime and wintertime Arctic Ocean primary marine aerosol properties

    Directory of Open Access Journals (Sweden)

    J. Zábori

    2013-05-01

    Full Text Available Primary marine aerosols (PMAs are an important source of cloud condensation nuclei, and one of the key elements of the remote marine radiative budget. Changes occurring in the rapidly warming Arctic, most importantly the decreasing sea ice extent, will alter PMA production and hence the Arctic climate through a set of feedback processes. In light of this, laboratory experiments with Arctic Ocean water during both Arctic winter and summer were conducted and focused on PMA emissions as a function of season and water properties. Total particle number concentrations and particle number size distributions were used to characterize the PMA population. A comprehensive data set from the Arctic summer and winter showed a decrease in PMA concentrations for the covered water temperature (Tw range between −1°C and 15°C. A sharp decrease in PMA emissions for a Tw increase from −1°C to 4°C was followed by a lower rate of change in PMA emissions for Tw up to about 6°C. Near constant number concentrations for water temperatures between 6°C to 10°C and higher were recorded. Even though the total particle number concentration changes for overlapping Tw ranges were consistent between the summer and winter measurements, the distribution of particle number concentrations among the different sizes varied between the seasons. Median particle number concentrations for a dry diameter (DpDp > 0.125μm, the particle number concentrations during winter were mostly higher than in summer (up to 50%. The normalized particle number size distribution as a function of water temperature was examined for both winter and summer measurements. An increase in Tw from −1°C to 10°C during winter measurements showed a decrease in the peak of relative particle number concentration at about a Dp of 0.180μm, while an increase was observed for particles with Dp > 1μm. Summer measurements exhibited a relative shift to smaller particle sizes for an increase of Tw in the range

  15. A method of harvesting gas hydrates from marine sediments

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.Q.; Brill, J.P.; Sarica, C. [Tulsa Univ., Tulsa, OK (United States). Dept. of Petroleum Engineering

    2008-07-01

    Methane is known to exist in gas hydrates, but low productivity is expected for gas production from gas hydrates in marine sediments because of the shallow depths, low hydrate concentration, low permeability of the gas hydrate stability zone, lack of driving pressure and the slow melting process. This paper presented a newly developed methane harvesting method which aims to overcome technical barriers, maintain cost and energy efficiencies and minimize safety and environmental concerns. The method is based on the concept of capturing the gas released from hydrate dissociation in the sediments. The captured gases can reform hydrates inside and overhead receiver, which once full, can be lifted to shallow warm water for gas collection. This simple and open production system does not require high pressure and does not involve any flow assurance issues. As such, technical difficulties, safety issues and environmental concerns are minimized. The proposed gas harvesting method makes the best use of the nature of hydrates and the subsea pressure and temperature profiles. It combines many new concepts, including electrically adding heat inside the hydrate rich sediments to release gas, using an overhead receiver to capture the gas, allowing the gas to reform hydrates again in the overhead receiver, and lifting produced hydrates to warm water where it can be released and collected. It was concluded that this newly proposed production system enables the development of massive hydrate production fields on the sea bed with high production rates that are economically viable. 4 refs., 7 figs.

  16. The bioremediation potential of marine sandy sediment microbiota

    Directory of Open Access Journals (Sweden)

    Dan Răzvan POPOVICIU

    2012-11-01

    Full Text Available The natural microbiota from marine sandy sediments on the Romanian sea coast was tested for resilience in case of hydrocarbon contamination, for estimating the number of (culturable hydrocarbon and lipid oil-degrading microorganisms and for determining the influence of inorganic nitrate and phosphate nutrients on hydrocarbon spill bioremediation process, by microcosm experiments.Results show that hydrocarbon contamination affects the bacteriobenthos both in terms of cell numbers and composition. Bacterial numbers showed a rapid decrease (28% in four days, followed by a relatively fast recovery (two weeks. The pollution favoured the increase of Gram-positive bacterial proportion (from around 25% to 33%Sandy sediment microbiota in both sites studied contained microorganisms able to use mineral or lipid oils as sole carbon sources, usually around 103-104/cm3, with variations according to the sediment grain size and substrate used.The biostimulation experiments showed that, in absence of water dynamism (and, implicitly, an efficient oxygenation, the addition of nitrogen and phosphorus can be ineffective and even inhibit the remediation process, probably due to eutrophication.

  17. Terrestrial Sediment Delivery to Coastal and Marine Environments: US Virgin Islands

    Science.gov (United States)

    Larson, R. A.; Brooks, G. R.; Devine, B.; Wallace, L. E.; Holmes, C. W.; Schwing, P. T.

    2007-05-01

    Understanding terrestrial sediment dynamics in high-relief, tropical island settings, such as St. Thomas and St. John, USVI, has become a critical issue, as sediments are a potential threat to the health of down-slope environments. The primary depositional sinks of terrestrial sediments are 1) coastal buffer zones such as salt ponds, which trap sediments and keep them from being input into the marine environment, and 2) near-shore marine environments (coral reefs, seagrasses, algal flats etc.), many of which are adversely affected by terrestrial sedimentation. Land use change by anthropogenic activities has been shown to alter terrestrial sediment dynamics and greatly increase sediment delivery and accumulation rates in coastal and marine environments. Sediment cores collected in salt ponds and the near-shore marine environment were used to determine the sedimentology (texture and composition) and geochronology (using 14C, and 210Pb) prior to anthropogenic activities to define the "natural signal", or "baseline", as well as recent deviations from the "natural signal", which may be attributed to anthropogenic activities. Salt pond and marine sediments in watersheds without anthropogenic activities exhibit no deviations from the "natural signal" in sedimentology or accumulation rate. Salt pond and marine sediments in watersheds with anthropogenic activities contain a deviation from the "natural signal" manifested as an increase in accumulation rate within the last 100 yrs (most likely within the last 25-50 yrs) ranging from 3 -10 times greater than the "natural" accumulation rate. Sedimentologically, salt ponds reflect no recent change, where as marine sediments do show a recent deviation in sedimentology. This marine deviation is represented by an increase in organic content, a decrease in grain size, and a decrease in carbonate content (marine-derived) compared to the "natural signal". This change reflects an increase in terrestrial (non- carbonate, finer

  18. Evaluation of marine sediments as microbial sources for methane production from brown algae under high salinity.

    Science.gov (United States)

    Miura, Toyokazu; Kita, Akihisa; Okamura, Yoshiko; Aki, Tsunehiro; Matsumura, Yukihiko; Tajima, Takahisa; Kato, Junichi; Nakashimada, Yutaka

    2014-10-01

    Various marine sediments were evaluated as promising microbial sources for methane fermentation of Saccharina japonica, a brown alga, at seawater salinity. All marine sediments tested produced mainly acetate among volatile fatty acids. One marine sediment completely converted the produced volatile fatty acids to methane in a short period. Archaeal community analysis revealed that acetoclastic methanogens belonging to the Methanosarcina genus dominated after cultivation. Measurement of the specific conversion rate at each step of methane production under saline conditions demonstrated that the marine sediments had higher conversion rates of butyrate and acetate than mesophilic methanogenic granules. These results clearly show that marine sediments can be used as microbial sources for methane production from algae under high-salt conditions without dilution.

  19. The freshwater fern Azolla (Azollaceae) from Eocene Arctic and Nordic Sea sediments: New species and their stratigraphic distribution

    NARCIS (Netherlands)

    van der Burgh, J.; Collinson, M.E.; van Konijnenburg-van Cittert, J.H.A.; Barke, J.; Brinkhuis, H.

    2013-01-01

    Three new species of the freshwater fern Azolla are described from Eocene marine deposits of the Arctic and Nordic seas, bringing the total number of species now documented from these areas to five. Azolla arctica Collinson et al., Azolla jutlandica Collinson et al., Azolla nova sp. nov. and Azolla

  20. Trophic transfer of persistent organochlorine contaminants (OCs) within an Arctic marine food web from the southern Beaufort-Chukchi Seas

    International Nuclear Information System (INIS)

    The trophic status and biomagnification of persistent OCs within the near-shore Beaufort-Chukchi Seas food web from Barrow, AK is discussed. - Stable isotope values (δ13C, δ15N) and concentrations of persistent organochlorine contaminants (OCs) were determined to evaluate the near-shore marine trophic status of biota and biomagnification of OCs from the southern Beaufort-Chukchi Seas (1999-2000) near Barrow, AK. The biota examined included zooplankton (Calanus spp.), fish species such as arctic cod (Boreogadus saida), arctic char (Salvelinus alpinus), pink salmon (Oncorhynchus gorbuscha), and fourhorn sculpin (Myoxocephalus quadricornis), along with marine mammals, including bowhead whales (Balaena mysticetus), beluga whales (Delphinapterus leucas), ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus). The isotopically derived trophic position of biota from the Beaufort-Chukchi Seas marine food web, avian fauna excluded, is similar to other coastal food webs in the Arctic. Concentrations of OCs in marine mammals were significantly greater than in fish and corresponded with determined trophic level. In general, OCs with the greatest food web magnification factors (FWMFs) were those either formed due to biotransformation (e.g. p,p'-DDE, oxychlordane) or considered recalcitrant (e.g. β-HCH, 2,4,5-Cl substituted PCBs) in most biota, whereas concentrations of OCs that are considered to be readily eliminated (e.g. γ-HCH) did not correlate with trophic level. Differences in physical-chemical properties of OCs, feeding strategy and possible biotransformation were reflected in the variable biomagnification between fish and marine mammals. The FWMFs in the Beaufort-Chukchi Seas region were consistent with reported values in the Canadian Arctic and temperate food webs, but were statistically different than FWMFs from the Barents and White Seas, indicating that the spatial variability of OC contamination in top-level marine Arctic predators is attributed to

  1. Trophic transfer of persistent organochlorine contaminants (OCs) within an Arctic marine food web from the southern Beaufort-Chukchi Seas

    Energy Technology Data Exchange (ETDEWEB)

    Hoekstra, P.F.; O' Hara, T.M.; Fisk, A.T.; Borgaa, K.; Solomon, K.R.; Muir, D.C.G

    2003-08-01

    The trophic status and biomagnification of persistent OCs within the near-shore Beaufort-Chukchi Seas food web from Barrow, AK is discussed. - Stable isotope values ({delta}{sup 13}C, {delta}{sup 15}N) and concentrations of persistent organochlorine contaminants (OCs) were determined to evaluate the near-shore marine trophic status of biota and biomagnification of OCs from the southern Beaufort-Chukchi Seas (1999-2000) near Barrow, AK. The biota examined included zooplankton (Calanus spp.), fish species such as arctic cod (Boreogadus saida), arctic char (Salvelinus alpinus), pink salmon (Oncorhynchus gorbuscha), and fourhorn sculpin (Myoxocephalus quadricornis), along with marine mammals, including bowhead whales (Balaena mysticetus), beluga whales (Delphinapterus leucas), ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus). The isotopically derived trophic position of biota from the Beaufort-Chukchi Seas marine food web, avian fauna excluded, is similar to other coastal food webs in the Arctic. Concentrations of OCs in marine mammals were significantly greater than in fish and corresponded with determined trophic level. In general, OCs with the greatest food web magnification factors (FWMFs) were those either formed due to biotransformation (e.g. p,p'-DDE, oxychlordane) or considered recalcitrant (e.g. {beta}-HCH, 2,4,5-Cl substituted PCBs) in most biota, whereas concentrations of OCs that are considered to be readily eliminated (e.g. {gamma}-HCH) did not correlate with trophic level. Differences in physical-chemical properties of OCs, feeding strategy and possible biotransformation were reflected in the variable biomagnification between fish and marine mammals. The FWMFs in the Beaufort-Chukchi Seas region were consistent with reported values in the Canadian Arctic and temperate food webs, but were statistically different than FWMFs from the Barents and White Seas, indicating that the spatial variability of OC contamination in top

  2. Recent Advances on Lipid Biomarkers in Marine Sediments

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-lin

    2014-01-01

    This paper reviews the recent advances of marine biomarker. Biomarkers of marine microorganisms are also included. It is important to the origin of marine biological and the monitor and evaluation of marine environment.

  3. Late Paleocene Arctic Ocean shallow-marine temperatures from mollusc stable isotopes

    Science.gov (United States)

    Bice, Karen L.; Arthur, Michael A.; Marincovich, Louie, Jr.

    1996-01-01

    Late Paleocene high-latitude (80°N) Arctic Ocean shallow-marine temperatures are estimated from molluscan δ18O time series. Sampling of individual growth increments of two specimens of the bivalve Camptochlamys alaskensis provides a high-resolution record of shell stable isotope composition. The heavy carbon isotopic values of the specimens support a late Paleocene age for the youngest marine beds of the Prince Creek Formation exposed near Ocean Point, Alaska. The oxygen isotopic composition of regional freshwater runoff is estimated from the mean δ18O value of two freshwater bivalves collected from approximately coeval fluviatile beds. Over a 30 – 34‰ range of salinity, values assumed to represent the tolerance of C. alaskensis, the mean annual shallow-marine temperature recorded by these individuals is between 11° and 22°C. These values could represent maximum estimates of the mean annual temperature because of a possible warm-month bias imposed on the average δ18O value by slowing or cessation of growth in winter months. The amplitude of the molluscan δ18O time series probably records most of the seasonality in shallow-marine temperature. The annual temperature range indicated is approximately 6°C, suggesting very moderate high-latitude marine temperature seasonality during the late Paleocene. On the basis of analogy with modern Chlamys species, C. alaskensis probably inhabited water depths of 30–50 m. The seasonal temperature range derived from δ18O is therefore likely to be damped relative to the full range of annual sea surface temperatures. High-resolution sampling of molluscan shell material across inferred growth bands represents an important proxy record of seasonality of marine and freshwater conditions applicable at any latitude. If applied to other regions and time periods, the approach used here would contribute substantially to the paleoclimate record of seasonality.

  4. Seasonal Changes in the Marine Production Cycles in Response to Changes in Arctic Sea Ice and Upper Ocean Circulation

    Science.gov (United States)

    Spitz, Y. H.; Ashjian, C. J.; Campbell, R. G.; Steele, M.; Zhang, J.

    2011-12-01

    Significant seasonal changes in arctic sea ice have been observed in recent years, characterized by unprecedented summer melt-back. As summer sea ice extent shrinks to record low levels, the peripheral seas of the Arctic Ocean are exposed much earlier to atmospheric surface heat flux, resulting in longer and warmer summers with more oceanic heat absorption. The changing seasonality in the arctic ice/ocean system will alter the timing, magnitude, duration, and pattern of marine production cycles by disrupting key trophic linkages and feedbacks in planktonic food webs. We are using a coupled pan-arctic Biology/Ice/Ocean Modeling and Assimilation System (BIOMAS) to investigate the changes in the patterns of seasonality in the arctic physical and biological system. Focus on specific regions of the Arctic, such as the Chukchi Sea, the Beaufort Sea and the adjacent central Arctic, reveals that changes in the timing of the spring bloom, its duration and the response of the secondary producers vary regionally. The major changes are, however, characterized by an earlier phytoplankton bloom and a slight increase of the biomass. In addition, the largest response in the secondary producers is seen in the magnitude of the microzooplankton concentration as well as in the period (early summer to late fall) over which the microzooplankton is present.

  5. The Arctic Ocean marine carbon cycle: evaluation of air-sea CO2 exchanges, ocean acidification impacts and potential feedbacks

    Directory of Open Access Journals (Sweden)

    N. R. Bates

    2009-11-01

    Full Text Available At present, although seasonal sea-ice cover mitigates atmosphere-ocean gas exchange, the Arctic Ocean takes up carbon dioxide (CO2 on the order of −66 to −199 Tg C year−1 (1012 g C, contributing 5–14% to the global balance of CO2 sinks and sources. Because of this, the Arctic Ocean has an important influence on the global carbon cycle, with the marine carbon cycle and atmosphere-ocean CO2 exchanges sensitive to Arctic Ocean and global climate change feedbacks. In the near-term, further sea-ice loss and increases in phytoplankton growth rates are expected to increase the uptake of CO2 by Arctic Ocean surface waters, although mitigated somewhat by surface warming in the Arctic. Thus, the capacity of the Arctic Ocean to uptake CO2 is expected to alter in response to environmental changes driven largely by climate. These changes are likely to continue to modify the physics, biogeochemistry, and ecology of the Arctic Ocean in ways that are not yet fully understood. In surface waters, sea-ice melt, river runoff, cooling and uptake of CO2 through air-sea gas exchange combine to decrease the calcium carbonate (CaCO3 mineral saturation states (Ω of seawater while seasonal phytoplankton primary production (PP mitigates this effect. Biological amplification of ocean acidification effects in subsurface waters, due to the remineralization of organic matter, is likely to reduce the ability of many species to produce CaCO3 shells or tests with profound implications for Arctic marine ecosystems

  6. Intercomparison of radionuclide measurements in marine sediment sample IAEA-135

    International Nuclear Information System (INIS)

    The results of an intercomparison exercise on a marine sediment from Irish Sea, IAEA-135, designed for the determination of artificial and natural radionuclides levels, are reported. The data from 151 laboratories representing 51 countries have been evaluated. The following are the recommended values, with confidence intervals, for 40K, 60Co, 134Cs, 137Cs, 154Eu, 155Eu, 226Ra, 228Ra, 232Th,238Pu, 239+240Pu (Reference date: 1 January 1992). Information values for 57Co, 90Sr, 106Ru, 125Sb, 210Pb, 210Po, 228Th, 230Th, 234U, 235U, 238U and 241Am are also reported. All values are expressed in Bq kg-1 dry weight. (author)

  7. Conspicuous veils formed by vibrioid bacteria on sulfidic marine sediment

    DEFF Research Database (Denmark)

    Thar, Roland Matthias; Kühl, Michael

    2002-01-01

    , but the bacteria have so far not been isolated in pure culture, and a detailed characterization of their metabolism is still lacking. The bacteria are colorless, gram-negative, and vibrioid-shaped (1.3- to 2.5- by 4- to 10-µm) cells that multiply by binary division and contain several spherical inclusions of poly......We describe the morphology and behavior of a hitherto unknown bacterial species that forms conspicuous veils (typical dimensions, 30 by 30 mm) on sulfidic marine sediment. The new bacteria were enriched on complex sulfidic medium within a benthic gradient chamber in oxygen-sulfide countergradients......-ß-hydroxybutyric acid. The cells have bipolar polytrichous flagella and exhibit a unique swimming pattern, rotating and translating along their short axis. Free-swimming cells showed aerotaxis and aggregated at ca. 2 µM oxygen within opposing oxygen-sulfide gradients, where they were able to attach via a mucous stalk...

  8. Chromophoric Dissolved Organic Matter across a Marine Distributed Biological Observatory in the Pacific Arctic Region

    Science.gov (United States)

    Berman, S. L.; Frey, K. E.; Shake, K. L.; Cooper, L. W.; Grebmeier, J. M.

    2014-12-01

    Dissolved organic matter (DOM) plays an important role in marine ecosystems as both a carbon source for the microbial food web (and thus a source of CO2 to the atmosphere) and as a light inhibitor in marine environments. The presence of chromophoric dissolved organic matter (CDOM; the optically active portion of total DOM) can have significant controlling effects on transmittance of sunlight through the water column and therefore on primary production as well as the heat balance of the upper ocean. However, CDOM is also susceptible to photochemical degradation, which decreases the flux of solar radiation that is absorbed. Knowledge of the current spatial and temporal distribution of CDOM in marine environments is thus critical for understanding how ongoing and future changes in climate may impact these biological, biogeochemical, and physical processes. We describe the quantity and quality of CDOM along five key productive transects across a developing Distributed Biological Observatory (DBO) in the Pacific Arctic region. The samples were collected onboard the CCGS Sir Wilfred Laurier in July 2013 and 2014. Monitoring of the variability of CDOM along transects of high productivity can provide important insights into biological and biogeochemical cycling across the region. Our analyses include overall concentrations of CDOM, as well as proxy information such as molecular weight, lability, and source (i.e., autochthonous vs. allochthonous) of organic matter. We utilize these field observations to compare with satellite-derived CDOM concentrations determined from the Aqua MODIS satellite platform, which ultimately provides a spatially and temporally continuous synoptic view of CDOM concentrations throughout the region. Examining the current relationships among CDOM, sea ice variability, biological productivity, and biogeochemical cycling in the Pacific Arctic region will likely provide key insights for how ecosystems throughout the region will respond in future

  9. Marine sediments as a radioactive pollution repository in the world

    International Nuclear Information System (INIS)

    During a time period little longer than 60 years, it has been created a radioactive pollution background over the natural one, which started in 1945 and it has been growing up since then, due to several nuclear tests, minor nuclear reactors failure and four major accidents: Wind Scale, Three Mile Island, Chernobyl and Fukushima. This radioactive polluting background can be easily detected through 137Cs fission product, which by the effect of wind, river currents and rain has been accumulated in marine sediments, mainly because sea represents about 80 % of earth's surface. Since energy demand has been growing up with no interruption during last two centuries, and nuclear energy seems to be the largest available source, it is very likely a great expansion of nuclear energy during twenty-first century. So, this paper presents results obtained in strategic points of the two large littorals in Mexico: Gulf and Pacific Ocean, as an attempt to establish there some figure to evaluate the present radioactive pollution. An adequate figure to do it, seems to be the quotient of activity per gram of 137Cs in marine sediments (Bq137Cs/g), divided by activity per gram of 40K natural radioactivity (Bq40K/g). When this result is multiplied by 100 the percentage of polluting radioactivity (137Cs) related to natural radioactivity (40K) is obtained. This percentage seems to be useful to evaluate the importance of radioactive pollution from 4 points of view: a) calculate the extent of already radioactive pollution present in the seas of world; b) avoid the panic in case of nuclear accidents, c) what will be the growing up rate in the future; d) if it is possible to keep one decreasing rate at same decaying rate of 137Cs (t1/2 = 30.07 years), since from 1945, starting time of radioactive pollution, it has decayed only about 2.2 half lives. (author)

  10. Radioactivity in Norwegian Waters: Distribution in seawater and sediments, and uptake in marine organisms

    Energy Technology Data Exchange (ETDEWEB)

    Heldal, Hilde Elise

    2001-07-01

    Prior to the detonation of the first thermonuclear bomb, small amounts of radioactivity, for example in mineral water, were considered to be health enriching. Negative experiences related to thermonuclear bombs and several nuclear accidents have, however, changed people's attitude towards radioactivity during the past 40-50 years. Today, there is a common concern for regular and potential accidental releases of radioactivity from sources such as Sellafield. Although this is important, incorrect assessments of the effects of these releases (e.g. created by uncritical journalism) have the potential to harm the country's fisheries and economy. Therefore, it is of major importance to document up-to-date levels of radioactive contamination of the marine environment, and be able to place these into the proper perspectives. The main topics of the thesis may be summarised as follows: (1) Distribution of Caesium-137, Plutonium-238, Plutonium-239,240 and Americium-241 in sediments with emphasis on the Spitsbergen-Bear Island area, (2) Uptake of Caesium-137 in phytoplankton representative for the Barents and Norwegian Seas phytoplankton communities (laboratory experiments), (3) Bioaccumulation of Caesium-137 in food webs in the Barents and Norwegian Seas, (4) Geographical variations of Caesium-137 in harbour porpoises (Phocoena phocoena) along the Norwegian coast, (5) Transport times for Technetium-99 from Sellafield to various locations along the Norwegian coast and the Arctic Ocean.

  11. Radioactivity in Norwegian Waters: Distribution in seawater and sediments, and uptake in marine organisms

    International Nuclear Information System (INIS)

    Prior to the detonation of the first thermonuclear bomb, small amounts of radioactivity, for example in mineral water, were considered to be health enriching. Negative experiences related to thermonuclear bombs and several nuclear accidents have, however, changed people's attitude towards radioactivity during the past 40-50 years. Today, there is a common concern for regular and potential accidental releases of radioactivity from sources such as Sellafield. Although this is important, incorrect assessments of the effects of these releases (e.g. created by uncritical journalism) have the potential to harm the country's fisheries and economy. Therefore, it is of major importance to document up-to-date levels of radioactive contamination of the marine environment, and be able to place these into the proper perspectives. The main topics of the thesis may be summarised as follows: (1) Distribution of Caesium-137, Plutonium-238, Plutonium-239,240 and Americium-241 in sediments with emphasis on the Spitsbergen-Bear Island area, (2) Uptake of Caesium-137 in phytoplankton representative for the Barents and Norwegian Seas phytoplankton communities (laboratory experiments), (3) Bioaccumulation of Caesium-137 in food webs in the Barents and Norwegian Seas, (4) Geographical variations of Caesium-137 in harbour porpoises (Phocoena phocoena) along the Norwegian coast, (5) Transport times for Technetium-99 from Sellafield to various locations along the Norwegian coast and the Arctic Ocean

  12. Bacterial diversity in oil-polluted marine coastal sediments.

    Science.gov (United States)

    Acosta-González, Alejandro; Marqués, Silvia

    2016-04-01

    Marine environments harbour a persistent microbial seed which can be shaped by changes of the environmental conditions such as contamination by petroleum components. Oil spills, together with small but continuous discharges of oil from transportation and recreational activities, are important sources of hydrocarbon pollution within the marine realm. Consequently, prokaryotic communities have become well pre-adapted toward oil pollution, and many microorganisms that are exposed to its presence develop an active degradative response. The natural attenuation of oil pollutants, as has been demonstrated in many sites, is modulated according to the intrinsic environmental properties such as the availability of terminal electron acceptors and elemental nutrients, together with the degree of pollution and the type of hydrocarbon fractions present. Whilst dynamics in the bacterial communities in the aerobic zones of coastal sediments are well characterized and the key players in hydrocarbon biodegradation have been identified, the subtidal ecology of the anaerobic community is still not well understood. However, current data suggest common patterns of response in these ecosystems.

  13. Meltwater history inferred from authigenic carbonates and fine grained glaciomarine sediments from the Mendeleev Ridge in the Arctic Ocean

    Science.gov (United States)

    Nam, Seung-Il; Woo, Kyung Sik; Ji, Hyo Seon; Stein, Ruediger; Mackensen, Andreas; Matthiessen, Jens

    2015-04-01

    Authigenic carbonates and mud fractions of the glaciomarine sediments were investigated texturally and geochemically. The sediment core (PS72/410-1) was retrieved using a giant box corer from the central Mendeleev Ridge of the western Arctic Ocean (Station location= Lat. 80°30.37"N, Long. 175°44.38"W) during the Polarstern Arctic expedition (PS72) in 2008. The core is 39 cm long with age of ca. 76 ka BP and was collected from the water depth of 1,802 meters. The sediments show various colours from grey to brown as previously reported in other Arctic deep sea sediments, reflecting glacial-interglacial and/or stadial-interstadial cycles. Authigenic carbonate minerals are present through the whole sequence except for a few centimetres. These authigenic carbonates are composed of high Mg-calcite, low Mg-calcite and aragonite. Various crystal shapes of aragonite and calcite together with clear growth shapes of the crystals suggest that they are inorganic in origin. Highly enriched carbon isotope compositions (δ13C = 0 ~ +5‰ vs. PDB) strongly indicate that they formed in methanogenic zone below sediment/water interface by the reaction between anoxic pore fluids and host sediments induced by methanogenic bacteria. However, a wide range of oxygen isotope values (δ18O = -5 ~ +5‰ vs. PDB) may indicate that porewater has been changed due to reaction between residual seawater and volcanic sediments. Relatively higher contents of K, Al, Fe and Be values from muddy sediments as well as low δ18O compositions of authigenic carbonates may imply strong input of meltwater from volcanic region (Eastern Arctic region) whereas higher oxygen isotope compositions of authigenic carbonates and higher Sr and K contents of mud sediments may reflect stronger influence from carbonate-rich region (Canadian Arctic region). Mineralogical changes form low to high Mg-calcite together with decrease in Mg, Sr and Fe contents strongly support less freshwater input from glacial mode to

  14. Zinc Isotope Ratios as Indicators of Diet and Trophic Level in Arctic Marine Mammals.

    Directory of Open Access Journals (Sweden)

    Klervia Jaouen

    Full Text Available Carbon and nitrogen stable isotope ratios of bone collagen are an established method for dietary reconstruction, but this method is limited by the protein preservation. Zinc (Zn is found in bioapatite and the isotopic compositions of this element constitute a very promising dietary indicator. The extent of fractionation of Zn isotopes in marine environments, however, remains unknown. We report here on the measurement of zinc, carbon and nitrogen isotopes in 47 marine mammals from the archaeological site of Arvik in the Canadian Arctic. We undertook this study to test and demonstrate the utility of Zn isotopes in recent mammal bone minerals as a dietary indicator by comparing them to other isotopic dietary tracers. We found a correlation between δ66Zn values and trophic level for most species, with the exception of walruses, which may be caused by their large seasonal movements. δ6Zn values can therefore be used as a dietary indicator in marine ecosystems for both modern and recent mammals.

  15. Zinc Isotope Ratios as Indicators of Diet and Trophic Level in Arctic Marine Mammals.

    Science.gov (United States)

    Jaouen, Klervia; Szpak, Paul; Richards, Michael P

    2016-01-01

    Carbon and nitrogen stable isotope ratios of bone collagen are an established method for dietary reconstruction, but this method is limited by the protein preservation. Zinc (Zn) is found in bioapatite and the isotopic compositions of this element constitute a very promising dietary indicator. The extent of fractionation of Zn isotopes in marine environments, however, remains unknown. We report here on the measurement of zinc, carbon and nitrogen isotopes in 47 marine mammals from the archaeological site of Arvik in the Canadian Arctic. We undertook this study to test and demonstrate the utility of Zn isotopes in recent mammal bone minerals as a dietary indicator by comparing them to other isotopic dietary tracers. We found a correlation between δ66Zn values and trophic level for most species, with the exception of walruses, which may be caused by their large seasonal movements. δ6Zn values can therefore be used as a dietary indicator in marine ecosystems for both modern and recent mammals. PMID:27010907

  16. Proceedings of the 29. Arctic and Marine Oilspill Program (AMOP) Technical Seminar

    International Nuclear Information System (INIS)

    This conference was a venue to exchange information on leading-edge technologies used in marine oil spill response operations. The different sessions at this conference were entitled: (1) physical and chemical properties and behaviour of spilled oil, (2) containment and recovery, (3) activity updates and contingency planning, (4) phytoremediation of inorganic and radionuclides, (5) biosolutions to site remediation, restoration and rehabilitation, (6) phytoremediation of petroleum hydrocarbons, (7) oil spill treating agents, (8) spill modelling, (9) detection, tracking and remote sensing, (10) special session on hurricanes, and (11) recent spill experiences. In addition to a poster session with papers, the conference also featured a technical seminar on chemical spills with a special session on counter-terrorism. Many presentations addressed the issue of optimizing response functions in harsh Arctic marine waters as well as strategy development for marine oil spill response and shoreline assessment. Several studies focused on oil-in-water interactions to find new mechanical, chemical and biological treatments for oil spills. All 65 presentations were indexed separately for inclusion in this database. refs., tabs., figs

  17. Geochemical and geological constraints on the composition of marine sediment pore fluid: Possible link to gas hydrate deposits

    Digital Repository Service at National Institute of Oceanography (India)

    Mazumdar, A.; Joao, H.M.; Peketi, A.; Dewangan, P.; Kocherla, M.; Joshi, R.K.; Ramprasad, T.

    Pore water sulfate consumption in marine sediments is controlled by microbially driven sulfate reduction via organo-clastic and methane oxidation processes. In this work, we present sediment pore fluid compositions of 10 long sediment cores and high...

  18. Input of Terrestrial Palynomorphs since the Last Deglaciation from Sediments of the Chukchi Sea Shelf, Western Arctic Ocean

    Science.gov (United States)

    Delusina, I.; Kim, S. Y.; Nam, S. I.; Woo, K. S.

    2014-12-01

    We report the palynology of marine sediment core ARA02B/01A-GC from the Western margin of the shallow shelf of the Chukchi Sea in the Arctic, a site which was synchronously influenced by climatic changes during the last deglaciation with those in the Bering Strait. The core contains a rich concentration of continental palynomorphs, even though the coring location is quite a distance from land. The catchment area for the observed palynomorphs includes the territories of both North America (Alaska and North Canada) and Northern Siberia (Chukotka peninsula and Northern East-Siberian coast). Based on this fact, we can reconstruct a common paleoenvironmental history for this location and the Bering Strait during the postglacial interval. We hypothesize that palynomorphs were carried to the sea during low sea-ice coverage intervals by large rivers (Yukon, Mackenzie and Siberian rivers) and were then transferred by oceanic currents. During intervals of extensive sea-ice coverage the source of the palynomorphs was predominantly eroded shelf sediments. The percentage ratio of tree-herb pollen and spores in the palynomorph assemblages shows that favorable conditions for an increase in forest vegetation took place between ~8 and 4 kyr BP, which coincides with maximum freshwater input to the sea. During a climatic optimum at ~5 kyr BP, as inferred from the total dominance of tree and herb pollen, the Chukchi Sea was apparently warmer than today. This represents the maximum ice-free period for the sea. The low sea-ice interval ended ~3 kyr BP, as suggested by a sharp drop in tree pollen, a reduction in fresh water input, and a drop in the concentration of the algae Pediastrum. Our data correlate well with data from marine core HLY0501-5 from the Bering Strait (Polyak et al., 2009) for the interval of 10-8 kyr BP, but shows a divergence since ~4 kyr BP, which may correspond to the beginning of the differentiation of North American and East-Siberian ecosystem zones.

  19. Temperature induced decoupling of enzymatic hydrolysis and carbon remineralization in long-term incubations of Arctic and temperate sediments

    DEFF Research Database (Denmark)

    Robador, Alberto; Brüchert, Volker; Steen, Andrew;

    2010-01-01

    , and 20 ºC. The short-term temperature response of the active microbial community was tested in temperature gradient block incubations. The temperature optimum of extracellular enzymatic hydrolysis, as measured with a polysaccharide (chondroitin sulfate), differed between Arctic and temperate habitats......Extracellular enzymatic hydrolysis of high-molecular weight organic matter is the initial step in sedimentary organic carbon degradation and is often regarded as the rate-limiting step. Temperature effects on enzyme activities may therefore exert an indirect control on carbon mineralization. We...... by about 8–13 C in fresh sediments and in sediments incubated for 24 months. In both Arctic and temperate sediments, the temperature response of chondroitin sulfate hydrolysis was initially similar to that of sulfate reduction. After 24 months, however, hydrolysis outpaced sulfate reduction rates, as...

  20. 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. PMID:26806662

  1. SOLID RADIOACTIVE WASTE STORAGE TECHNOLOGIES: PERFORMANCE OF A POLYMER SEALANT COATING IN AN ARCTIC MARINE ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    COWGILL,M.G.; MOSKOWITZ,P.D.; CHERNAENKO,L.M.; NAZARIAN,A.; GRIFFITH,A.; DIASHEV,A.; ENGOY,T.

    2000-06-14

    This first project, under the auspices of the Arctic Military Environmental Cooperation (AMEC) forum, Project 1.4-1 Solid Radioactive Waste Storage Technologies, successfully demonstrated the feasibility of using a polymer-based coating to seal concrete and steel surfaces from permanent radioactive contamination in an Arctic marine environment. A mobile, self-sufficient spraying device, was developed to specifications provided by the Russian Ministry of Defence Northern Navy and was deployed at the RTP Atomflot site, Murmansk, Russia. Demonstration coatings of Polibrid 705 were applied to concrete surfaces exposed to conditions ranging from indoor pedestrian usage to heavy vehicle passage and container handling in a loading bay. A large steel container was also coated with the polymer, filled with solid radwaste, sealed, and left out of doors and exposed to the full 12 month Arctic weather cycle. The field tests were accompanied by a series of laboratory qualification tests carried out at the research laboratory of ICC Nuclide in St. Petersburg. During the 12-month field tests, the sealant coating showed little sign of degradation except for a few chips and gouge marks on the loading bay surface that were readily repaired. Contamination resulting from radwaste handling was easily removed and the surface was not degraded by contact with the decontamination agents. In the laboratory testing, Polibrid 705 met all the Russian qualification requirements with the exception of flammability. In this last instance, it was decided to restrict application of the coating to land-based facilities. The Russian technical experts from the Ministry of Defence quickly familiarized themselves with the equipment and were able to identify several areas of potential improvement as deployment of the equipment progressed. The prime among these was the desirability of extending the range of the equipment through enlarged gasoline tanks (to permit extended operational times) and longer

  2. Organic carbon cycling in marine sediments and seabed seepage features in Irish waters

    OpenAIRE

    O'Reilly, Shane S.

    2013-01-01

    Cycling of organic carbon in marine sediments is of fundamental importance for marine ecosystem function, for marine and atmospheric chemistry, for the petroleum and natural gas industry, and for paleoclimatic and paleoenvironmental studies. While most of this carbon is derived from marine and terrestrial sources, significant improvements in mapping and remote investigation have revealed that seabed fluid flow, principally in the form of thermogenic or microbial methane, is also of fundame...

  3. Untypical even-to-odd predominance in the low-molecular n-alkanes of water, suspended matter, and bottom sediments in some regions of the Arctic Basin

    Science.gov (United States)

    Drozdova, Anastasia; Belyaev, Nikolay; Ponyaev, Mikhail

    2014-05-01

    Over the years, several studies have shown an unusual predominance of even-carbon number n-alkanes in dissolved and particulate phase samples and sediment samples from various regions of the World Ocean [Nachman, 1985; Nishimura and Baker, 1985; Elias et al., 1997]. Different possible sources were proposed such as diagenesis (diagenetic origin from co-occurring fatty acids and alcohols), direct microbial input, microbial degradation of algal detritus, etc. Some researchers, however, are incredulous about this phenomenon and consider relatively high content of even-carbon number n-alkanes as contamination during the experiments. We report here the results of GC and GC-MS analysis of water, suspended particulate matter and sediment samples collected during 7 marine and coastal scientific expeditions to the White and Kara Seas, and to the central Arctic Basin (2004-2013). Many of the above samples (more than 30) present n-alkane distribution with a strong even-carbon number predominance of n-C14H30, and n-C16H34. Maximum enrichment was observed in some suspended matter samples with predominance of n-C16H34. The origin of even-carbon number n-alkanes in marine ecosystems is still not clear. In Antarctic region n-C16 and n-C18 and other even chain n-alkanes were reported to be dominant in the samples of the sea-ice algae, zooplankton and fish [Green et al. 1997] however in the Arctic region this phenomenon has not been demonstrated yet. Increasing of bacteria number and δ13C values observed in course of the accompanying studies [Lein et al., 2013] suggest existence of mechanism of phytoplankton bacterial destruction in the Arctic ecosystems, leading to formation of even-carbon number n-alkanes. R.J. Nachman - Lipids, Vol. 20, No 9, pp. 629-633 (1985). M. Nishimura, E.W. Baker - Geochim. et Cosmochim. Acta, Vol. 50, pp. 299-305 (1986). V.O. Elias, B.R.T. Simoneit, J.N. Cardoso - Naturwissenschaften, Vol. 84, pp. 415-420 (1997). G. Green et al. - Marine Pollution

  4. Performance of a polymer sealant coating in an arctic marine environment

    International Nuclear Information System (INIS)

    The feasibility of using a polymer-based coating, Polibrid 705, to seal concrete and steel surfaces from permanent radioactive contamination in an Arctic marine environment has been successfully demonstrated using a combination of field and laboratory testing. A mobile, self-sufficient spraying device was developed to specifications provided by the Russian Northern Navy and deployed at the RTP Atomflot site, Murmansk, Russia. Demonstration coatings were applied to concrete surfaces exposed to conditions ranging from indoor pedestrian usage to heavy vehicle passage and container handling in a loading dock. A large steel container was also coated with the polymer, filled with solid radwaste, sealed, and left out of doors, exposed to the full annual Arctic weather cycle. The 12 months of field testing gave rise to little degradation of the sealant coating, except for a few chips and gouge marks on the loading bay surface that were readily repaired. Contamination resulting from radwaste handling was easily removed and the surface was not degraded by contact with the decontamination agents. The field tests were accompanied by a series of laboratory qualification tests carried out at a research laboratory in St. Petersburg. The laboratory tests examined a variety of properties, including bond strength between the coating and the substrate, thermal cycling resistance, wear resistance, flammability, and ease of decontamination. The Polibrid 705 coating met all the Russian Navy qualification requirements with the exception of flammability. In this last instance, it was decided to restrict application of the coating to land-based facilities

  5. Western Arctic Vulnerability to Warming over the past 3.6 Myr: Lessons from sediments drilled at Lake El'gygytgyn, Western Beringia

    Science.gov (United States)

    Brigham-Grette, J.; Melles, M.; Minyuk, P.; Lake El'gygytgyn Science Team

    2011-12-01

    International Continental Deep drilling (ICDP) at Lake El'gygytgyn (67_30' N, 172_05' E; "Lake E"), recovered lacustrine sediments dating back to 3.6 Ma that provides the first time-continuous Pliocene-Pleistocene paleoclimate record of different interglacials from the terrestrial Arctic. While discontinuous, spatially diverse Pliocene and Pleistocene marine interglacial records are known from the arctic borderlands at the outcrop scale, the Lake El'gygytgyn record is critically important understanding the western Arctic landscape response to different forcing factors operating across the Arctic since the mid-Pliocene warm period. The record is important for evaluating the sensitivity of the Arctic region and to provide a template of Arctic climate variability that can be compared to other regions. Lake E modeling is framed around suites of sensitivity tests of Beringian climate response to the full range of forcing experienced over the last ~3.5 million years using a nested Global-Regional Climate Model (GCM-RCM). The Pliocene portion of the lake record (~3.6-3.0 Ma; a time when atmospheric CO2 levels may have been like today) has nearly twice the sedimentation rate as later Quaternary intervals, partly as a consequence of basin infilling but also presumably due to more rainfall and more active rivers at that time. Studies of spores and pollen from this portion of the core (samples every ~10k) show that the area was once dominated by trees, providing us with the pace of variability in Pliocene Arctic forests, which included species of pine, larch, spruce, fir, alder, and hemlock. Hemlock and tree pine pollen is exceptional for this latitude but the assemblage implies July temperatures nearly 8 degrees warmer than today with ~3 times the annual precipitation. Modeling suggests sustained forests at Lake E in both cold and warm orbits during this interval. The record includes a strong M2 cooling event to conditions like today at ~3.3 Ma, but not glacial climates as

  6. Effect of sediment properties on the sorption of C{sub 12}-2-LAS in marine and estuarine sediments

    Energy Technology Data Exchange (ETDEWEB)

    Rico-Rico, Angeles [Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 2, 3508 TD Utrecht (Netherlands)], E-mail: a.ricorico@uu.nl; Temara, Ali [Procter and Gamble Company, Central Product Safety, Temselaan 100, 1853 Strombeek-Bever (Belgium); Behrends, Thilo [Department of Earth Sciences-Geochemistry, Faculty of Geosciences, Utrecht University, 3508 TA Utrecht (Netherlands); Hermens, Joop L.M. [Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 2, 3508 TD Utrecht (Netherlands)

    2009-02-15

    Linear alkylbenzene sulfonates (LAS) are anionic high production volume surfactants used in the manufacture of cleaning products. Here, we have studied the effect of the characteristics of marine and estuarine sediments on the sorption of LAS. Sorption experiments were performed with single sediment materials (pure clays and sea sand), with sediments treated to reduce their organic carbon content, and with field marine and estuarine sediments. C{sub 12}-2-LAS was used as a model compound. Sorption to the clays montmorillonite and kaolinite resulted in non-linear isotherms very similar for both clays. When reducing the organic content, sorption coefficients decreased proportionally to the fraction removed in fine grain sediments but this was not the case for the sandy sediment. The correlation of the sediment characteristics with the sorption coefficients at different surfactant concentrations showed that at concentrations below 10 {mu}g C{sub 12}-2-LAS/L, the clay content correlated better with sorption, while the organic fraction became more significant at higher concentrations. - Sorption of C{sub 12}-2-LAS to marine sediments mainly depends on both clay and organic carbon content. The importance of each parameter varies with the surfactant concentration.

  7. Changing Arctic ecosystems--research to understand and project changes in marine and terrestrial ecosystems of the Arctic

    Science.gov (United States)

    Geiselman, Joy; DeGange, Anthony R.; Oakley, Karen; Derksen, Dirk; Whalen, Mary

    2012-01-01

    Ecosystems and their wildlife communities are not static; they change and evolve over time due to numerous intrinsic and extrinsic factors. A period of rapid change is occurring in the Arctic for which our current understanding of potential ecosystem and wildlife responses is limited. Changes to the physical environment include warming temperatures, diminishing sea ice, increasing coastal erosion, deteriorating permafrost, and changing water regimes. These changes influence biological communities and the ways in which human communities interact with them. Through the new initiative Changing Arctic Ecosystems (CAE) the U.S. Geological Survey (USGS) strives to (1) understand the potential suite of wildlife population responses to these physical changes to inform key resource management decisions such as those related to the Endangered Species Act, and (2) provide unique insights into how Arctic ecosystems are responding under new stressors. Our studies examine how and why changes in the ice-dominated ecosystems of the Arctic are affecting wildlife and will provide a better foundation for understanding the degree and manner in which wildlife species respond and adapt to rapid environmental change. Changes to Arctic ecosystems will be felt broadly because the Arctic is a production zone for hundreds of species that migrate south for the winter. The CAE initiative includes three major research themes that span Arctic ice-dominated ecosystems and that are structured to identify and understand the linkages between physical processes, ecosystems, and wildlife populations. The USGS is applying knowledge-based modeling structures such as Bayesian Networks to integrate the work.

  8. Integrated approach to the toxicity evaluation of Irish marine sediments: exotoxicological assessment

    OpenAIRE

    Macken, Ailbhe

    2007-01-01

    The quality of sediment in any aquatic ecosystem is vital to the health of that system. Sediments have been recognised as a major repository for persistent toxic substances. If sediments become sufficiently polluted they can lead to the disruption of surrounding natural biological communities. Therefore the monitoring of sediment quality is essential for successful ecosystem functioning in the marine environment. The aim of the present study was to employ an integrated approach of the toxicit...

  9. Development of whole sediment bioassay using the marine/estuarine polychaetes Polydora cornuta Bosc 1802 and Boccardia proboscidea Hartman 1940

    Energy Technology Data Exchange (ETDEWEB)

    Pocklington, P. [Arenicola Marine, Dartmouth, Nova Scotia (Canada); Doe, K.; Huybers, A.; Wade, S. [Environment Canada, Dartmouth, Nova Scotia (Canada). Environmental Quality Lab.; Lee, D. [Environment Canada, North Vancouver, British Columbia (Canada). Pacific Environmental Science Centre

    1995-12-31

    The growing need by Environment Canada for a battery of marine toxicity tests has prompted the development of chronic, sublethal, sediment bioassay tests using marine or estuarine annelids (polychaetes). Initially several species of polychaetes found in the Atlantic, Pacific and Arctic waters were assessed and a few of these were selected for testing survival and sensitivity under laboratory conditions and sensitivity to reference toxicants using field collected specimens. From these experiments, the authors identified several promising species and attempts were made to culture them. To date they have been successful in culturing one species from the Atlantic coast--Polydora cornuta and one species from the Pacific Coast--Boccardia proboscidea. They have been able to generate sufficient numbers of same-age larvae, raise them under controlled conditions to juveniles/young adults, and, subject them to a variety of Non-Contaminant Effects Trials (NCETs) and Contaminant Effects Trials (CETs). In the NCETs the authors determined the effect of food type and food ration, temperature, salinity, grain size, length of test condition. They found them to be moderately robust in terms of variable environmental parameters. In the CETs they found this species to be sensitive to sediments considered by Environment Canada to be toxic. They also determined the animal`s sensitivity to a reference toxicant CdCl{sub 2} (96 hr LC50).

  10. Sonobuoy-based velocity functions for sediment thickness calculation in the deep Canada Basin of the Arctic Ocean

    Science.gov (United States)

    Lebedeva-Ivanova, N. N.; Hart, P. E.; Chian, D.; Shimeld, J.; Lizarralde, D.; Hutchinson, D. R.; Mosher, D. C.

    2012-12-01

    The deep Canada Basin, which occupies much of the western (Amerasian) Arctic Ocean, is one of the most unexplored and difficult areas on Earth for marine seismic acquisition due to permanent sea ice cover. It extends northward from the Alaskan and Canadian margins for ~500 km and is characterized by a remarkably flat sea floor at 3.6-3.8 km below sea level (bsl) and covers ~500,000 km^2. A set of 143 sonobuoy records were collected during 2007-2010 over the Canada Basin by US-Canada collaborative expeditions. The sonobuoys were deployed along short streamer multi-channel seismic (MCS) lines for estimating seismic velocities in the sediments. A spatial coverage of sonobuoys at every ~80 km on MCS lines provides data for robust average empirical time-depth conversion functions.Sediments are nearly sub-horizontal and sub-parallel, mostly undisturbed with maximum two-way travel time (TWTT)thicknesses of ~5 s, but not greater than ~2.5-3.0 s TWTT closer to the Alpha Ridge and the Chukchi Borderland. Semblance velocity analysis has been applied to the sonobuoy records to determine sediment thickness and depth using the Dix equation. Assuming flat-lying sediments, the normal-moveout (NMO) velocity is approximately equal to the root-mean-square (RMS) average velocity from the sea surface to the reflection horizon. A dip of 5 degrees effects velocity less than 0.5%. Semblance velocity analyses were completed for 128 of 143 sonobuoy records in the deep Canada Basin; 25 records were excluded from later analysis due to bad quality or location on the slope. Results were also converted to interval velocities and depths.The RMS velocities were consistently picked from clear high-coherency events to yield only increasing interval velocities.Picking stopped at or above the bright reflection interpreted as basement on the MCS. Velocities were not picked on dipping reflections surfaces, along the margins where the seafloor was dipping, nor for sedimentary horizons characterized by

  11. Summertime aerosol chemical components in the marine boundary layer of the Arctic Ocean

    Science.gov (United States)

    Xie, Zhouqing; Sun, Liguang; Blum, Joel D.; Huang, Yuying; He, Wei

    2006-05-01

    Samples of aerosols from the marine boundary layer of the Arctic Ocean were collected aboard the R/V Xuelong during summer on the Second Chinese Arctic Research Expedition (July-September 2003). Synchrotron radiation X-ray fluorescence (SR-XRF) was used to determine chemical compositions of aerosol particles. Multivariate analysis of the SR-XRF data resolved a number of components (factors), which, on the basis of their chemical compositions and from their affiliation with specific meteorological flow patterns, were assigned physical meanings. Five factors explaining 94.7% of the total variance were identified. Ship emissions accounted for 35.3% of the variance (factor 1 (F1)) and are loaded significantly with S, Fe, V, and Ni. The total Fe emitted from ships globally was estimated at 8.60 × 106 kg yr-1. Heavy-metal-rich factors included 34.0% of the variance (F2 and F3) and were interpreted to be pollution carried into the Arctic Ocean by long-range transport. Anthropogenic contributions from industrial regions to the Arctic Ocean during the summer vary and depend on the source locations. Air mass backward trajectories indicate that the metals including Hg, Pb, Cu, and Zn come mainly from northern Russia. The third source controlling the chemical compositions of aerosols was sea salt (F4, 12.8%). The role of sea salt decreased from the open sea to areas near pack ice. On the basis of the factor scores of aerosol samples, we infer that chlorine volatilization from sea salt may occur, enhanced by nitrogen and sulfur contamination emitted from ships. Because the global inventories of nitrogen and sulfur for ship exhausts are large, and halogens could have important consequences in possible tropospheric ozone destruction, the role of ships in influencing halogen depression in sea salt should be further investigated. Finally, we also identified a crustal factor (F5, 12.6%) and suggest that crustal elements (e.g., Ca) contaminating sea ice may become reinjected into

  12. Comparison between summertime and wintertime Arctic Ocean primary marine aerosol properties

    Directory of Open Access Journals (Sweden)

    J. Zábori

    2012-12-01

    Full Text Available Primary marine aerosols (PMA are an important source of cloud condensation nuclei, and one of the key elements of the remote marine radiative budget. Changes occurring in the rapidly warming Arctic, most importantly the decreasing sea ice extent will alter PMA production and hence the Arctic climate through a set of feedback processes. In light of this, laboratory experiments with Arctic Ocean water during both Arctic winter and summer were conducted and focused on PMA emissions as a function of season and water properties. Total particle number concentrations and particle number size distributions were used to characterize the PMA population. A comprehensive data set from the Arctic summer and winter showed a decrease in PMA concentrations for the covered water temperature (Tw range between −1 °C and 15 °C. A sharp decrease in PMA emissions for a Tw increase from −1 °C to 4 °C was followed by a lower rate of change in PMA emissions for Tw up to about 6 °C. Near constant number concentrations for water temperatures between 6 °C to 10 °C and higher were recorded. Even though the total particle number concentrations changes for overlapping Tw ranges were consistent between the summer and winter measurements, the distribution of particle number concentrations among the different sizes varied between the seasons. Median particle number concentrations for Dp < 0.125 μm measured during winter conditions were similar (deviation of up to 3%, or lower (up to 70% than the ones measured during summer conditions (for the same water temperature range. For Dp > 0.125 μm, the particle number concentrations during winter were mostly higher than in summer (up to 50%. The normalized particle number size distribution as a function of water temperature was examined for both winter and summer measurements. An increase in Tw from

  13. Low organotin contamination of harbour sediment in Svalbard

    OpenAIRE

    Den Heuvel-Greve, van, Martine J.; Szczybelski, Ariadna S.; Den Brink, van, Nico W.; Kotterman, Michiel J. J.; Kwadijk, Christiaan J.A.F.; Evenset, Anita; Murk, Albertinka J.

    2016-01-01

    Arctic sea routes are opening up for maritime transport due to sea ice retreat leading to increasing human activities in the Arctic and concomitant pressures on the environment. Organotin compounds are used in antifouling paints of large seagoing vessels and are known to leach into the marine environment and accumulate in sediments and biota. As organotin levels in Svalbard sediments have not been documented in peer-reviewed literature before, this study describes the levels in sediment of ha...

  14. Diversity of active aerobic methanotrophs along depth profiles of arctic and subarctic lake water column and sediments

    Science.gov (United States)

    He, Ruo; Wooller, Matthew J.; Pohlman, John W.; Quensen, John; Tiedje, James M.; Leigh, Mary Beth

    2012-01-01

    Methane (CH4) emitted from high-latitude lakes accounts for 2–6% of the global atmospheric CH4 budget. Methanotrophs in lake sediments and water columns mitigate the amount of CH4 that enters the atmosphere, yet their identity and activity in arctic and subarctic lakes are poorly understood. We used stable isotope probing (SIP), quantitative PCR (Q-PCR), pyrosequencing and enrichment cultures to determine the identity and diversity of active aerobic methanotrophs in the water columns and sediments (0–25 cm) from an arctic tundra lake (Lake Qalluuraq) on the north slope of Alaska and a subarctic taiga lake (Lake Killarney) in Alaska's interior. The water column CH4 oxidation potential for these shallow (~2m deep) lakes was greatest in hypoxic bottom water from the subarctic lake. The type II methanotroph, Methylocystis, was prevalent in enrichment cultures of planktonic methanotrophs from the water columns. In the sediments, type I methanotrophs (Methylobacter, Methylosoma and Methylomonas) at the sediment-water interface (0–1 cm) were most active in assimilating CH4, whereas the type I methanotroph Methylobacter and/or type II methanotroph Methylocystis contributed substantially to carbon acquisition in the deeper (15–20 cm) sediments. In addition to methanotrophs, an unexpectedly high abundance of methylotrophs also actively utilized CH4-derived carbon. This study provides new insight into the identity and activity of methanotrophs in the sediments and water from high-latitude lakes.

  15. Elemental depth profiles in marine sediments of Singapore coastal waters

    International Nuclear Information System (INIS)

    Thirty-eight core sediment samples were recently collected from different locations of the Singapore coastal region. The aim of the project was to trace the history of marine pollution in various coastal regions and to determine the impact of industrial activities. Two nuclear analytical techniques were employed in this study: particle induced X-ray emission (PIXE), Rutherford backscattering (RBS) as well as X-ray fluorescence (XRF). Combined together these techniques provide an excellent tool to determine elemental concentrations of more than 30 elements with detection limits as low as few ppm. Our results show that elemental concentrations in most of the regions do not show a significant variation with depth. However, in regions where industrial and shipping activities are high, for example the Port of Singapore area and the northern part of Johore Straits, the concentrations of metals like Cr, Ni, Cu, Zn, Sn and Pb were found to have an obvious decreasing trend with the depth. In these cores, concentrations in the top 10-15 cm were sometimes ten times higher than the corresponding base line concentrations. Elemental depth profiles of Ni, Cu, Zn, As, Sn and Pb and their mean concentrations in various regions are reported and discussed

  16. Microbes of deep marine sediments as viewed by metagenomics

    Science.gov (United States)

    Biddle, J.

    2015-12-01

    Ten years after the first deep marine sediment metagenome was produced, questions still exist about the nucleic acid sequences we have retrieved. Current data sets, including the Peru Margin, Costa Rica Margin and Iberian Margin show that consistently, data forms larger assemblies at depth due to the reduced complexity of the microbial community. But are these organisms active or preserved? At SMTZs, a change in the assembly statistics is noted, as well as an increase in cell counts, suggesting that cells are truly active. As depth increases, genome sizes are consistently large, suggesting that much like soil microbes, sedimentary microbes may maintain a larger reportorie of genomic potential. Functional changes are seen with depth, but at many sites are not correlated to specific geochemistries. Individual genomes show changes with depth, which raises interesting questions on how the subsurface is settled and maintained. The subsurface does have a distinct genomic signature, including unusual microbial groups, which we are now able to analyze for total genomic content.

  17. Biogeography and Photosynthetic Biomass of Arctic Marine Pico-Eukaroytes during Summer of the Record Sea Ice Minimum 2012.

    Science.gov (United States)

    Metfies, Katja; von Appen, Wilken-Jon; Kilias, Estelle; Nicolaus, Anja; Nöthig, Eva-Maria

    2016-01-01

    Information on recent photosynthetic biomass distribution and biogeography of Arctic marine pico-eukaryotes (0.2-3 μm) is needed to better understand consequences of environmental change for Arctic marine ecosystems. We analysed pico-eukaryote biomass and community composition in Fram Strait and large parts of the Central Arctic Ocean (Nansen Basin, Amundsen Basin) using chlorophyll a (Chl a) measurements, automated ribosomal intergenic spacer analysis (ARISA) and 454-pyrosequencing. Samples were collected during summer 2012, the year with the most recent record sea ice minimum. Chl a concentrations were highest in eastern Fram Strait and pico-plankton accounted for 60-90% of Chl a biomass during the observation period. ARISA-patterns and 454-pyrosequencing revealed that pico-eukaryote distribution is closely related to water mass distribution in the euphotic zone of the Arctic Ocean. Phaeocystaceae, Micromonas sp., Dinophyceae and Syndiniales constitute a high proportion of sequence reads, while sequence abundance of autotrophic Phaeocystaceae and mixotrophic Micromonas sp. was inversely correlated. Highest sequence abundances of Phaeocystaceae were observed in the warm Atlantic Waters in Fram Strait, while Micromonas sp. dominated the abundant biosphere in the arctic halocline. Our results are of particular interest considering existing hypotheses that environmental conditions in Nansen Basin might become more similar to the current conditions in Fram Strait. We propose that in response, biodiversity and biomass of pico-eukaryotes in Nansen Basin could resemble those currently observed in Fram Strait in the future. This would significantly alter biogeochemical cycles in a large part of the Central Arctic Ocean. PMID:26895333

  18. Biogeography and Photosynthetic Biomass of Arctic Marine Pico-Eukaroytes during Summer of the Record Sea Ice Minimum 2012.

    Directory of Open Access Journals (Sweden)

    Katja Metfies

    Full Text Available Information on recent photosynthetic biomass distribution and biogeography of Arctic marine pico-eukaryotes (0.2-3 μm is needed to better understand consequences of environmental change for Arctic marine ecosystems. We analysed pico-eukaryote biomass and community composition in Fram Strait and large parts of the Central Arctic Ocean (Nansen Basin, Amundsen Basin using chlorophyll a (Chl a measurements, automated ribosomal intergenic spacer analysis (ARISA and 454-pyrosequencing. Samples were collected during summer 2012, the year with the most recent record sea ice minimum. Chl a concentrations were highest in eastern Fram Strait and pico-plankton accounted for 60-90% of Chl a biomass during the observation period. ARISA-patterns and 454-pyrosequencing revealed that pico-eukaryote distribution is closely related to water mass distribution in the euphotic zone of the Arctic Ocean. Phaeocystaceae, Micromonas sp., Dinophyceae and Syndiniales constitute a high proportion of sequence reads, while sequence abundance of autotrophic Phaeocystaceae and mixotrophic Micromonas sp. was inversely correlated. Highest sequence abundances of Phaeocystaceae were observed in the warm Atlantic Waters in Fram Strait, while Micromonas sp. dominated the abundant biosphere in the arctic halocline. Our results are of particular interest considering existing hypotheses that environmental conditions in Nansen Basin might become more similar to the current conditions in Fram Strait. We propose that in response, biodiversity and biomass of pico-eukaryotes in Nansen Basin could resemble those currently observed in Fram Strait in the future. This would significantly alter biogeochemical cycles in a large part of the Central Arctic Ocean.

  19. Bestemmelse af partikelstørrelsesfordeling og -overflade i jord og marine sedimenter med laser diffraktion

    DEFF Research Database (Denmark)

    Callesen, Ingeborg; Joest Andersen, Thorbjørn; Rasmussen, Charlotte;

    2016-01-01

    Rapporten beskriver resultaterne af en serie målinger af partikelstørrelsesfordeling ved laser diffraktion på jordprøver fra sorterede og usorterede udgangsmaterialer fra skovjorde og fra marine sedimenter.......Rapporten beskriver resultaterne af en serie målinger af partikelstørrelsesfordeling ved laser diffraktion på jordprøver fra sorterede og usorterede udgangsmaterialer fra skovjorde og fra marine sedimenter....

  20. Origin of authigenic calcite and aragonite in pelagic sediments of the Mendeleev Ridge (Arctic Ocean) and their paleoceanographicimplications

    Science.gov (United States)

    Woo, K. S.; Ji, H. S.; Nam, S.; Stein, R. H.; Mackensen, A.; Matthiessen, J. J.

    2013-12-01

    Carbonate minerals were discovered from the giant box core (PS72/410-1) of the pelagic sediments recovered from the Canadian Arctic across the central Mendeleev Ridge (Station location= Lat. 80°30.37"N, Long. 175°44.38"W) during the Arctic cruise by Polarstern in 2008. The core was 39 cm long and was collected from the water depth of 1802 meters. The sediments show various colours from grey to brown as previously reported in other Arctic pelagic sediments. The sediments include planktonic foraminifers together with carbonate minerals. The contents of planktonic foraminifers and carbonate minerals vary with core depth, however these carbonate minerals are present through the whole sequence except for a few centimetres. After wet sieving, coarse fractions were texturally examined with binocular microscope and SEM, and stable isotope and trace element contents were obtained. Mineralogy of carbonate minerals were determined using crystal shapes and qualitative Sr contents by EDAX together with trace element analysis. The carbonates are composed of high Mg-calcite, low Mg-calcite and aragonite. Aragonite crystals show (1) radiating fibrous texture, (2) randomly oriented fibrous texture, (3) spherulitic fibrous texture, and (4) bladed texture, and calcite crystals show (1) foliated texture, (2) randomly bladed texture, (3) spherulitic fibrous texture, and (4) equant texture. Various crystal shapes of aragonite and calcite together with clear growth shapes of the crystals suggest that they are inorganic in origin. Highly enriched carbon isotope compositions (δ13C = 0 ~ +5‰ vs. PDB) strongly indicate that they formed in methanogenic zone below sediment/water interface by the reaction between anoxic pore fluids and host sediments induced by methanogenic bacteria. However, a wide range of oxygen isotope values (δ18O = -5 ~ +5‰ vs. PDB) may indicate that porewater has been changed due to reaction between residual seawater and volcanic sediments. Four types of stable

  1. Reconstruction of a high-resolution late holocene arctic paleoclimate record from Colville River delta sediments.

    Energy Technology Data Exchange (ETDEWEB)

    Schreiner, Kathryn Melissa; Lowry, Thomas Stephen

    2013-10-01

    This work was partially supported by the Sandia National Laboratories, Laboratory Directed Research and Development (LDRD) fellowship program in conjunction with Texas A&M University (TAMU). The research described herein is the work of Kathryn M. Schreiner (Katie) and her advisor, Thomas S. Bianchi and represents a concise description of Katies dissertation that was submitted to the TAMU Office of Graduate Studies in May 2013 in partial fulfillment of her doctorate of philosophy degree. High Arctic permafrost soils contain a massive amount of organic carbon, accounting for twice as much carbon as what is currently stored as carbon dioxide in the atmosphere. However, with current warming trends this sink is in danger of thawing and potentially releasing large amounts of carbon as both carbon dioxide and methane into the atmosphere. It is difficult to make predictions about the future of this sink without knowing how it has reacted to past temperature and climate changes. This project investigated long term, fine scale particulate organic carbon (POC) delivery by the high-Arctic Colville River into Simpsons Lagoon in the near-shore Beaufort Sea. Modern POC was determined to be a mixture of three sources (riverine soils, coastal erosion, and marine). Downcore POC measurements were performed in a core close to the Colville River output and a core close to intense coastal erosion. Inputs of the three major sources were found to vary throughout the last two millennia, and in the Colville River core covary significantly with Alaskan temperature reconstructions.

  2. Reconstruction of a high-resolution late holocene arctic paleoclimate record from Colville River delta sediments.

    Energy Technology Data Exchange (ETDEWEB)

    Schreiner, Kathryn Melissa; Lowry, Thomas Stephen

    2013-10-01

    This work was partially supported by the Sandia National Laboratories,Laboratory Directed Research and Development' (LDRD) fellowship program in conjunction with Texas A&M University (TAMU). The research described herein is the work of Kathryn M. Schreiner (Katie') and her advisor, Thomas S. Bianchi and represents a concise description of Katie's dissertation that was submitted to the TAMU Office of Graduate Studies in May 2013 in partial fulfillment of her doctorate of philosophy degree. High Arctic permafrost soils contain a massive amount of organic carbon, accounting for twice as much carbon as what is currently stored as carbon dioxide in the atmosphere. However, with current warming trends this sink is in danger of thawing and potentially releasing large amounts of carbon as both carbon dioxide and methane into the atmosphere. It is difficult to make predictions about the future of this sink without knowing how it has reacted to past temperature and climate changes. This project investigated long term, fine scale particulate organic carbon (POC) delivery by the high-Arctic Colville River into Simpson's Lagoon in the near-shore Beaufort Sea. Modern POC was determined to be a mixture of three sources (riverine soils, coastal erosion, and marine). Downcore POC measurements were performed in a core close to the Colville River output and a core close to intense coastal erosion. Inputs of the three major sources were found to vary throughout the last two millennia, and in the Colville River core covary significantly with Alaskan temperature reconstructions.

  3. Diversity of active aerobic methanotrophs along depth profiles of arctic and subarctic lake water column and sediments

    OpenAIRE

    He, Ruo; Wooller, Matthew J; Pohlman, John W.; Quensen, John; Tiedje, James M.; Leigh, Mary Beth

    2012-01-01

    Methane (CH4) emitted from high-latitude lakes accounts for 2–6% of the global atmospheric CH4 budget. Methanotrophs in lake sediments and water columns mitigate the amount of CH4 that enters the atmosphere, yet their identity and activity in arctic and subarctic lakes are poorly understood. We used stable isotope probing (SIP), quantitative PCR (Q-PCR), pyrosequencing and enrichment cultures to determine the identity and diversity of active aerobic methanotrophs in the water columns and sedi...

  4. Burrowing and avoidance behaviour in marine organisms exposed to pesticide-contaminated sediment

    DEFF Research Database (Denmark)

    Møhlenberg, Flemming; Kiørboe, Thomas

    1983-01-01

    Behavioural effects of marine sediment contaminated with pesticides (6000 ppm parathion, 200 ppm methyl parathion, 200 ppm malathion) were studied in a number of marine organisms in laboratory tests and in situ. The burrowing behaviour in Macoma baltica, Cerastoderma edule, Abra alba, Nereis...

  5. Origin and geochemical behavior of uranium in marine sediments. Utilization of the 234U/238U ratio in marine geochemistry

    International Nuclear Information System (INIS)

    The first part of this thesis presents the current situation of knowledge of uranium in marine environment. The second part describes the methods of analysis as well as the material support of the study, i.e., the sediments and marine deposits investigated. The third part is dedicated to the study of uranium mobility in marine sediments characterized by detrital terrigenous composition (pelagic clays). This approach allowed quantifying the entering and leaving flux of uranium after the sediment settling and, to discuss, on this basis, the consequences on the uranium oceanic balance. In the third part the origin and behavior of uranium in zones of high surface productivity is studied. The uranium enrichments observed in the hemi-pelagic sediments of the EUMELI (J.G.O.F.S.-France) programme will constitute a material of study adequate for measuring the variations in the 234U/238U ratio in solid phase, in response to the oxido-reducing characteristics of the sediment. Thus establishing the origin of the trapped uranium has been possible. Also, the nature of the sedimentary phases related to uranium in bio-genetic sediments in the Austral Ocean was determined. Thus a relationship between the variations in the 234U/238 and the diagenetic transformations was possible to establish. Finally in the fifth part a study of the behavior of uranium in a polymetallic shell characteristic for deposits of hydrogenized origin

  6. Multiple climatic signals inferred from the varved sediments of a coastal lake in the Canadian High Arctic

    Science.gov (United States)

    Amann, Benjamin; Lamoureux, Scott F.

    2016-04-01

    The Arctic is extremely sensitive to climate change, and an influential part of the global climate system. However, the assessment of climate change and impacts from the Arctic remains a challenge mainly due to short and sparse meteorological records. In this context, data from natural paleoclimate archives are fundamental to place climate variability into perspective and assess the sensitivity of Earth's climate to natural and anthropogenic forcings. In particular, Arctic lakes are excellent potential archives. They are sensitive to extreme seasonal variations in surface processes and have a limited direct human impact. Nevertheless, the study of Arctic lakes is an analytical and technical challenge because: (i) limnological information are often lacking due to difficult accessibility; (ii) 210Pb inventories are low and terrestrial macrofossils for 14C dating are rare, which limits the development of precise sediment chronologies; and (iii) sediment accumulation rates are often low, which may restrict the temporal resolution and length of the paleoclimate records. Here, we present a high-resolution record from the varved sediments (annual laminations) of a saline coastal lake located in the Canadian High Arctic (unofficial name Chevalier Lake; Melville Island, NT). The particular interest of this location is the catchment area: 152 times larger than the lake area (Ac = 350 km²; AL = 2.3 km²). This particularity generates high sedimentation rates, atypical of previously studied arctic lakes. Two sediment cores were recovered from the centre and a more proximal zone of the lake. We used microstratigraphy supported by X-ray fluorescence data (Zr/K for particle size, Fe/Rb for the winter clay cap distinction) to develop a precise and cross-dated varve chronology covering the last 400 years. Dating of the uppermost section could be validated with preliminary 137Cs data. Stratigraphical analysis reveals the presence of three sediment units within the meter

  7. Pathways and Microbiology of Thiosulfate Transformations and Sulfate Reduction in a Marine Sediment (Kattegat, Denmark)

    DEFF Research Database (Denmark)

    JØRGENSEN, BB; BAK, F.

    1991-01-01

    Reductive and oxidative pathways of the sulfur cycle were studied in a marine sediment by parallel radiotracer experiments with (SO4(2-))-S-35, (H2S)-S-35, and (S2O3(2-))-S-35 injected into undisturbed sediment cores. The distributions of viable populations of sulfate- and thiosulfate-reducing ba...

  8. Chemoautotrophic Carbon Fixation Rates and Active Bacterial Communities in Intertidal Marine Sediments

    NARCIS (Netherlands)

    Boschker, H.T.S.; Vasquez-Cardenas, D.; Bolhuis, H.; Moerdijk-Poortvliet, T.C.W.; Moodley, L.

    2014-01-01

    Chemoautotrophy has been little studied in typical coastal marine sediments, but may be an important component ofcarbon recycling as intense anaerobic mineralization processes in these sediments lead to accumulation of high amounts ofreduced compounds, such as sulfides and ammonium. We studied chemo

  9. FRAM-2012: Norwegians return to the High Arctic with a Hovercraft for Marine Geophysical Research

    Science.gov (United States)

    Hall, J. K.; Kristoffersen, Y.; Brekke, H.; Hope, G.

    2012-12-01

    After four years of testing methods, craft reliability, and innovative equipment, the R/H SABVABAA has embarked on its first FRAM-201x expedition to the highest Arctic. Named after the Inupiaq word for 'flows swiftly over it', the 12m by 6m hovercraft has been home-based in Longyearbyen, Svalbard since June 2008. In this, its fifth summer of work on the ice pack north of 81N, the craft is supported by the Norwegian Petroleum Directorate (NPD) via the Nansen Environmental and Remote Sensing Center (NERSC) in Bergen, and the Norwegian Scientific Academy for Polar Research. FRAM-2012 represents renewed Norwegian interest in returning to the highest Arctic some 116 years after the 1893-96 drift of Fridtjof Nansen's ship FRAM, the first serious scientific investigation of the Arctic. When replenished by air or icebreaker, the hovercraft Sabvabaa offers a hospitable scientific platform with crew of two, capable of marine geophysical, geological and oceanographic observations over long periods with relative mobility on the ice pack. FRAM-2012 is the first step towards this goal, accompanying the Swedish icebreaker ODEN to the Lomonosov Ridge, north of Greenland, as part of the LOMROG III expedition. The science plan called for an initial drive from the ice edge to Gakkel Ridge at 85N where micro-earthquakes would be monitored, and then to continue north to a geological sampling area on the Lomonosov Ridge at about 88N, 65W. The micro-earthquake monitoring is part of Gaute Hope's MSc thesis and entails five hydrophones in a WiFi-connected hydrophone array deployed over the Gakkel Rift Valley, drifting with the ice at up to 0.4 knots. On August 3 the hovercraft was refueled from icebreaker ODEN at 84-21'N and both vessels proceeded north. The progress of the hovercraft was hampered by insufficient visibility for safe driving and time consuming maneuvering in and around larger fields of rubble ice impassable by the hovercraft, but of little concern to the icebreaker. It

  10. Assessment of crude oil biodegradation in arctic seashore sediments: effects of temperature, salinity, and crude oil concentration.

    Science.gov (United States)

    Sharma, Priyamvada; Schiewer, Silke

    2016-08-01

    The expected increase in offshore oil exploration and production in the Arctic may lead to crude oil spills along arctic shorelines. To evaluate the potential effectiveness of bioremediation to treat such spills, oil spill bioremediation in arctic sediments was simulated in laboratory microcosms containing beach sediments from Barrow (Alaska), spiked with North Slope Crude, and incubated at varying temperatures and salinities. Biodegradation was measured via respiration rates (CO2 production); volatilization was quantified by gas chromatography/mass spectrophotometry (GC/MS) analysis of hydrocarbons sorbed to activated carbon, and hydrocarbons remaining in the sediment were quantified by GC/flame ionization detector (FID). Higher temperature leads to increased biodegradation by naturally occurring microorganisms, while the release of volatile organic compounds was similar at both temperatures. Increased salinity had a small positive impact on crude oil removal. At higher crude oil dosages, volatilization increased, however CO2 production did not. While only a small percentage of crude oil was completely biodegraded, a larger percentage was volatilized within 6-9 weeks. PMID:27072034

  11. Surface-enhanced in-situ Raman-sensor applied in the arctic area for analyses of water and sediment

    Science.gov (United States)

    Kolomijeca, Anna; Kwon, Yong-Hyok; Kronfeldt, Heinz-Detlef

    2012-06-01

    Investigations on the seafloor in the arctic area are of great scientific interest as well as of progressive economic importance. Therefore, measurements in the water column and of sediments were carried out by applying different analytical methods. In JCR 253 arctic cruise a microsystem diode laser with reflection Bragg grating emitting at 671 nm was introduced and integrated into an optode housing which was laboratory pressure tested up to 200 bar. The connection to the mobile spectrometer is realized through an optical fiber. All performed measurements were carried out on the James-Clark-Ross research vessel during a three week experiment in August 2011. Conventional Raman spectra and SERS spectra of arctic surface water and sediment acquired from locations around 78° N and 9° E will be presented. Selected SERS substrates developed for SERS measurements in sea-water were tested for their capability to detect different substances in the water down to very small (pmol/l) concentrations. Additionally, the applicability of shifted excitation Raman difference spectroscopy (SERDS) and a combination of SERS with SERDS for analytical applications during sea-trials for in-situ analyses of sea-water and sediments will be discussed.

  12. Oil spill related contaminant data for Arctic marine mammals - Obtaining baseline oil spill-related contaminant exposure data for Arctic marine mammals

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — With increasing oil exploration and ship traffic in the U.S. Arctic, there is concern about the increased potential for an oil spill event in this region of the...

  13. Ice rafting history and paleoceanographic reconstructions of Core 08P23 from southern Chukchi Plateau, western Arctic Ocean since Marine Isotope Stage 3

    Institute of Scientific and Technical Information of China (English)

    ZHANG Taoliang; WANG Rujian; XIAO Wenshen; CHEN Zhihua; CHEN Jianfang; CHENG Zhenbo; SUN Yechen

    2015-01-01

    Multiproxy investigations have been performed on Core 08P23 collected from the Chukchi Plateau, the western Arctic Ocean, during the Third Chinese National Arctic Expedition. The core was dated back to Ma-rine Isotope Stage (MIS) 3 by a combination of Accelerator Mass Spectrometric (AMS) carbon-14 dating and regional core correlation. A total of five prominent ice-rafted detritus (IRD) events were recognized in MIS 2 and MIS 3. The IRD sources in MIS 3 are originated from vast carbonate rock outcrops of the Canadian Arctic Archipelago and clastic quartz in MIS 2 may have a Eurasian origin. Mostδ18O andδ13C values of Neogloboquadrina pachyderma (sinistral) (Nps) in Core 08P23 are lighter than the average values of surface sediments. The lighterδ18O andδ13C values of Nps in the two brown layers in MIS 1 and MIS 3 were resulted from meltwater events; and those in the gray layers in MIS 3 were caused by the enhanced sea ice formation. Theδ18O values varied inversely withδ13C in MIS 2 indicate that the study area was covered by thick sea ice or ice sheet with low temperature and little meltwater, which prevented the biological productivity and sea-atmosphere exchange, as well as water mass ventilation. The covaried light values ofδ18O andδ13C in MIS 1 and MIS 3 were resulted from meltwater and/or brine injection.

  14. Does temporal variation of mercury levels in Arctic seabirds reflect changes in global environmental contamination, or a modification of Arctic marine food web functioning?

    Science.gov (United States)

    Fort, Jérôme; Grémillet, David; Traisnel, Gwendoline; Amélineau, Françoise; Bustamante, Paco

    2016-04-01

    Studying long-term trends of contaminants in Arctic biota is essential to better understand impacts of anthropogenic activities and climate change on the exposure of sensitive species and marine ecosystems. We concurrently measured temporal changes (2006-2014) in mercury (Hg) contamination of little auks (Alle alle; the most abundant Arctic seabird) and in their major zooplankton prey species (Calanoid copepods, Themisto libellula, Gammarus spp.). We found an increasing contamination of the food-chain in East Greenland during summer over the last decade. More specifically, bird contamination (determined by body feather analyses) has increased at a rate of 3.4% per year. Conversely, bird exposure to Hg during winter in the northwest Atlantic (determined by head feather analyses) decreased over the study period (at a rate of 1.5% per year), although winter concentrations remained consistently higher than during summer. By combining mercury levels measured in birds and zooplankton to isotopic analyses, our results demonstrate that inter-annual variations of Hg levels in little auks reflect changes in food-chain contamination, rather than a reorganization of the food web and a modification of seabird trophic ecology. They therefore underline the value of little auks, and Arctic seabirds in general, as bio-indicators of long-term changes in environmental contamination. PMID:26798998

  15. Does temporal variation of mercury levels in Arctic seabirds reflect changes in global environmental contamination, or a modification of Arctic marine food web functioning?

    Science.gov (United States)

    Fort, Jérôme; Grémillet, David; Traisnel, Gwendoline; Amélineau, Françoise; Bustamante, Paco

    2016-04-01

    Studying long-term trends of contaminants in Arctic biota is essential to better understand impacts of anthropogenic activities and climate change on the exposure of sensitive species and marine ecosystems. We concurrently measured temporal changes (2006-2014) in mercury (Hg) contamination of little auks (Alle alle; the most abundant Arctic seabird) and in their major zooplankton prey species (Calanoid copepods, Themisto libellula, Gammarus spp.). We found an increasing contamination of the food-chain in East Greenland during summer over the last decade. More specifically, bird contamination (determined by body feather analyses) has increased at a rate of 3.4% per year. Conversely, bird exposure to Hg during winter in the northwest Atlantic (determined by head feather analyses) decreased over the study period (at a rate of 1.5% per year), although winter concentrations remained consistently higher than during summer. By combining mercury levels measured in birds and zooplankton to isotopic analyses, our results demonstrate that inter-annual variations of Hg levels in little auks reflect changes in food-chain contamination, rather than a reorganization of the food web and a modification of seabird trophic ecology. They therefore underline the value of little auks, and Arctic seabirds in general, as bio-indicators of long-term changes in environmental contamination.

  16. Molecular Approaches to Understanding C & N Dynamics in MArine Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Arturo Massol; James Tiedje; Jizhong Zhou; Allan Devol

    2007-05-16

    Continental margin sediments constitute only about 10% of the total sediment surface area in the world’s oceans, nevertheless they are the dominant sites of nitrogen (N) cycling. Recent studies suggest that the oceanic nitrogen budget is unbalanced, primarily due to a higher nitrogen removal rate in contrast to the fixation rate, and it has been suggested that denitrification activity contributes significantly to this imbalance. Although denitrification in marine environments has been studied intensively at the process level, little is known about the species abundance, composition, distribution, and functional differences of the denitrifying population. Understanding the diversity of microbial populations in marine environments, their responses to various environmental factors such as NO3-, and how this impact the rate of denitrification is critical to predict global N dynamics. Environmental Microbiology has the prompt to study the influence of each microbial population on a biogeochemical process within a given ecosystem. Culture-dependent and –independent techniques using nucleic acid probes can access the identity and activity of cultured and uncultured microorganisms. Nucleic acid probes can target distintict genes which set phylogenetic relationships, such as rDNA 16S, DNA gyrase (gyrB) and RNA polymerase sigma 70 factor (rpoD). In the other hand, the genetic capabilities and their expression could be tracked using probes that target several functional genes, such as nirS, nirK, nosZ, and nifH, which are genes involved in denitrification. Selective detection of cells actively expressing functional genes within a community using In Situ Reverse Transcription-PCR (ISRT-PCR) could become a powerful culture-independent technique in microbial ecology. Here we describe an approach to study the expression of nirS genes in denitrifying bacteria. Pure cultures of Pseudomonas stutzeri and Paracoccus denitrificans, as well as co-cultures with non

  17. Erosion of soil organic carbon at high latitudes and its delivery to Arctic Ocean sediments: New source to sink insight from radiocarbon dating

    Science.gov (United States)

    Hilton, Robert; Galy, Valier; Gaillardet, Jerome; Dellinger, Mathieu; Bryant, Charlotte; O'Regan, Matt; Grocke, Darren; Coxall, Helen

    2016-04-01

    Soils of the northern high latitudes store carbon over thousands of years and contain almost double the carbon stock of the atmosphere. Erosion processes can mobilise this pre-aged soil organic carbon from the landscape and supply it to rivers. If it escapes degradation during river transport and is delivered to the coastal ocean, this carbon may be sequestered for much longer periods of time (>104 yr) as a geological CO2 sink. Despite this recognition, the erosional flux and fate of particulate organic carbon (POC) in large rivers draining the high latitudes remains poorly constrained. Using radiocarbon activity, we quantify POC source, flux and fate in the Mackenzie River, the main sediment supplier to the Arctic Ocean. When combined with stable carbon isotopes and element ratios, the radiocarbon activity of POC allows us to distinguish inputs of POC from sedimentary rocks and quantify the average age of biospheric POC (from vegetation and soil) transported through the river system. We find that the eroded biospheric POC has resided in the basin for millennia, with a mean radiocarbon age of 5800±800 years. This is much older than large tropical rivers where we have equivalent data (Amazon River, Ganges River), and likely reflects the longer residence time of organic matter in cold, wet, high latitude soils. Based on the measured biospheric POC content and annual sediment flux, we calculate a biospheric POC flux of 2.2 (+1.3/-0.9) TgC yr-1 from the Mackenzie River. This is the largest input of aged organic carbon to the Arctic Ocean, more than the combined POC flux from the Eurasian Rivers. Offshore, we use a marine core to investigate organic carbon burial over the Holocene period. Radiocarbon measurements of bulk organic carbon reveal a significant offset from benthic foraminifera radiocarbon ages throughout the core, which is dependent upon the grain size of the sediments. Organic matter in sediments >63μm are offset from foraminifera by ˜ 6,000 14C years

  18. Deinococcus enclensis sp. nov., isolated from a marine sediment sample.

    Science.gov (United States)

    Thorat, Meghana N; Mawlankar, Rahul; Sonalkar, Vidya V; Venkata Ramana, V; Joseph, Neetha; Shouche, Yogesh S; Dastager, Syed G

    2015-01-01

    A novel pale-pink coloured strain, designated NIO-1023(T), was isolated from a marine sediment sample from Chorao Island, Goa, India. The taxonomic position of strain NIO-1023(T) was investigated by using a polyphasic approach. The cells were observed to be Gram-stain positive, coccal shaped and non-spore forming. Phylogenetic analyses using the 16S rRNA gene sequence of the isolate indicated that the organism belongs to the genus Deinococcus. The strain NIO-1023(T) showed highest 16S rRNA gene sequence similarities with Deinococcus ficus (97.8 %), whereas other Deinococcus species showed less than 95 % sequence similarity. The DNA-DNA relatedness with respect to D. ficus CC-FR2-10(T) was 23.9 %. Chemotaxonomic data revealed that strain NIO-1023(T) contains only menaquinone MK-8 as the respiratory quinone and a complex polar lipid profile consisting of different unidentified glycolipids and polar lipids, two unknown phospholipids and three unknown phosphoglycolipids. As in other deinococci, one of these phosphoglycolipids was predominant in the profile. The predominant fatty acids were identified as C17:1 w8c, C16:1 w6c/w7c, C15:1 w6c and C17:1 w9c. The genomic DNA G + C content of strain NIO-1023(T) was determined to be 67.2 mol%. The biochemical and chemotaxonomic properties demonstrate that strain NIO-1023(T) represents a novel species, for which the name Deinococcus enclensis sp. nov. is proposed. The type strain is NIO-1023(T) (=DSM 25127(T) = NCIM 5456(T)).

  19. The remedial investigation of marine sediment at the United Heckathorn Superfund site

    Energy Technology Data Exchange (ETDEWEB)

    White, P.J.; Kohn, N.P.; Gardiner, W.W.; Word, J.Q. [Battelle/Marine Sciences Lab., Sequim, WA (United States)

    1994-02-01

    The former United Heckathom site in Richmond, California, was used to process and package chlorinated pesticides from the 1940s to the mid-1960s. These activities resulted in the contamination of upland soils and marine sediment in the adjacent waterways. Battelle/Marine Sciences Laboratory (MSL) was requested by USEPA to conduct a remedial investigation and feasibility study (RI/FS). of the marine portion of the site. The objectives of this RI are to determine the extent of pesticide contamination in inner Richmond Harbor, estimate the total volume of contaminated sediment, characterize the subsurface geology; characterize the biological effects of contaminated sediment; and characterize the quality of effluent derived from dewatered sediment through treatability testing. Sediment cores were collected from 53 stations. Vertical subsamples from each sediment core were analyzed for chlorinated pesticides. Sediment from selected cores was also analyzed for other contaminants. Younger Bay Mud (YBM) sediment from multiple stations was mixed to form composite samples representing various segments of the study area. These composites were used for solid-phase toxicity and bioaccumulation tests, and the preparation of liquid-phase samples for treatability testing. The probable quality of effluent produced by dewatering sediment was evaluated by chemical and toxicological testing of suspended-particulate-phase (SPP) and elutriate samples.

  20. Geochemistry of marine sediments of the Brazilian Northeastern continental shelf

    Directory of Open Access Journals (Sweden)

    Fernanda Souza do Nascimento

    2010-01-01

    Full Text Available The marine sediment samples collected from the northeastern Brazilian continental shelf, at water depths between 20 and 80 m, consisted mainly of sands with an almost total absence of gravel and granules. Medium, coarse and very coarse sand grains are mostly composed of halimeda, lithothamnium, rodoliths and bioclastic sands with a carbonate content varying between 77 and 96 %. The chemistry in general shows a decreasing content of Ca (86.1 % >Si (6 % > Cl (3.6 % > Sr (0.8 % > K (0.66 % > S (0.62 % > Al (0.6 % > Na (0.55% > Mg (0.43 % > Fe (0.4 % > P (0.2 % > Br (0.04 % in the samples. There was no correlation between CaCO3 and chemical contents and grain size with depth and bio-components. With the exception of Sr of marine origin, all other elements (P, S, Br, Cl, Fe are of continental origin. The lithothamnium of some offshore samples shows higher CaCO3 content, while Mg and Na are present only in halimedas. Bioclastic sands contain no Br, and silt and clay fractions are rare and characterize samples closer to the coast. These marine bioclastic granulates are of very pure biogenic calcium carbonates and are thus highly to be recommended for economic purposes.Os granulados marinhos, da Plataforma Continental do nordeste brasileiro, coletados de profundidades entre 20 e 80 m, são predominantemente areias cascalhosas constituídas de halimedas, litotames, rodolitos e areias bioclásticas, cujos teores de carbonatos variam de 77 a 96 %. A concentração média geral de elementos químicos na ordem decrescente é Ca (86.1 % > Si (6 % > Cl (3.6 % > Sr (0.8 % > K (0.66 % > S (0.62 % > Al (0.6 % > Na (0.55 % > Mg (0.43 % > Fe (0.4 % > P (0.2 % > Br (0,04 %, independentemente da profundidade e tipo de bio-componente. Com exceção do Sr, que é de origem marinha, os demais elementos (P, S, Br, Cl, Fe são de origem continental. Elementos como Mg e Na foram restritos às halimedas em apenas duas amostras, enquanto Br não foi detectado nas areias

  1. Relative sea level and coastal environments in arctic Alaska during Marine Isotope Stage 5

    Science.gov (United States)

    Farquharson, L. M.; Mann, D. H.; Jones, B. M.; Rittenour, T. M.; Grosse, G.; Groves, P.

    2015-12-01

    Marine Isotope Stage (MIS) 5 was characterized by marked fluctuations in climate, the warmest being MIS 5e (124-119 ka) when relative sea level (RSL) stood 2-10 m higher than today along many coastlines. In northern Alaska, marine deposits now 5-10 m above modern sea level are assigned to this time period and termed the Pelukian transgression (PT). Complicating this interpretation is the possibility that an intra-Stage 5 ice shelf extended along the Alaskan coast, causing isostatic depression along its grounded margins, which caused RSL highs even during periods of low, global RSL. Here we use optically stimulated luminescence (OSL) to date inferred PT deposits on the Beaufort Sea coastal plain. A transition from what we interpret to be lagoonal mud to sandy tidal flat deposits lying ~ 2.75 m asl dates to 113+/-18 ka. Above this, a 5-m thick gravelly barrier beach dates to 95 +/- 20 ka. This beach contains well-preserved marine molluscs, whale vertebrae, and walrus tusks. Pleistocene-aged ice-rich eolian silt (yedoma) blanket the marine deposits and date to 57.6 +/-10.9 ka. Our interpretation of this chronostratigraphy is that RSL was several meters higher than today during MIS 5e, and lagoons or brackish lakes were prevalent. Gravel barrier beaches moved onshore as local RSL rose further after MIS 5e. The error range of the OSL age of the barrier-beach unit spans the remaining four substages of MIS 5; however, the highstand of RSL on this arctic coastline appears to occurr after the warmest part of the last interglacial and appears not to be coeval with the eustatic maximum reached at lower latitudes during MIS 5. One possibility is that RSL along the Beaufort Sea coast was affected by isostatic depression caused by an ice shelf associated with widespread, intra-Stage 5 glaciation that was out of phase with lower latitude glaciation and whose extent and timing remains enigmatic.

  2. Viable Species of Flamella (Amoebozoa: Variosea) Isolated from Ancient Arctic Permafrost Sediments.

    Science.gov (United States)

    Shmakova, Lyubov; Bondarenko, Natalya; Smirnov, Alexey

    2016-02-01

    Six viable strains of amoebae belonging to the genus Flamella (Amoebozoa, Variosea) were isolated from permafrost sediments sampled in the Russian Arctic region. Two of them are from late Pleistocene permafrost in North-East Siberia, and four--from Holocene and late Pleistocene in North-West Siberia. Light- and electron-microscopic study and molecular phylogeny show that these isolates represent two new species belonging to the genus Flamella. Both species are cyst-forming. This is a remarkable case of high resistance of protozoan cysts, allowing them to survive and recover an amoebae population after a very long, geologically significant period of rest; a "snapshot" of evolution in time. This study directly shows for the first time that amoeba cysts can be conserved not only for years and decades but for many thousand years and then recover, contributing to the formation of an active microbial community. We propose to name the new species as Flamella pleistocenica n.sp. and Flamella beringiania n.sp. Phylogenetic analysis shows that the genus Flamella is a robust and potentially species-rich group of Variosea. PMID:26735346

  3. Polychlorinated naphthalenes (PCNs) in riverine and marine sediments of the Laizhou Bay area, North China

    Energy Technology Data Exchange (ETDEWEB)

    Pan Xiaohui [Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Tang Jianhui, E-mail: jhtang@yic.ac.cn [Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Chen Yingjun [Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Li Jun; Zhang Gan [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2011-12-15

    PCN congeners were analyzed in marine and riverine sediments of the Laizhou Bay area, North China. Concentrations of PCNs ranged from 0.12 to 5.1 ng g{sup -1} dry weight (dw) with a mean value of 1.1 ng g{sup -1} dw. The levels of PCNs varied largely, with industrial group approximately ten folds higher than those of the rural in riverine sediment. A strong impact by direct discharge from local factories was suggested. Similar compositional profiles were found within groups. High resemblance of compositional profiles between industrial samples and Halowax 1014 was observed. It was indicated that PCNs in riverine sediments were mainly from release of industrial usage, with additional contributions from industrial thermal process at certain sites. In marine sediments, it was suggested that PCNs along the coast of Laizhou Bay were mainly controlled by riverine input. While in the central bay, PCN distributions were possibly impacted by combined multiple factors. - Highlights: > We investigated the PCN levels both in the riverine and marine surface sediments of Laizhou Bay. > PCN concentrations in the river sediments of industrial group were ten times higher than in the rural group. > Leakage from industrial materials and thermal processes were the major sources. > PCNs in the coastal sites were more influenced by the river discharge. > In the centre bay, PCN distributions were possibly impacted by combined multiple factors. - A systematic sampling of riverine and marine sediments was conducted in Laizhou Bay area to investigate the distribution and possible sources of PCNs.

  4. Acetate consumption in anoxic marine sediments: Identification of key players using mixed pure cultures and sediment incubations

    DEFF Research Database (Denmark)

    Na, Hyunsoo

    are largely unknown. The main goal of my PhD project was to identify acetate consumers in sulfate-reducing sediments of Aarhus Bay, Denmark. More specifically, we addressed the hypothesis if sulfate-reducing bacteria and methanogenic archaea can oxidize acetate in syntrophy. First, we examined the changes......-existence in sulfate-rich environments. Taken together, the results from my PhD study extend our knowledge on the range of microorganisms potentially involved in acetate turnover in anoxic marine sediments. These included new groups of sulfate-reducing bacteria, and other uncultured bacterial and archaeal members....... While we did not find methanogens to be involved in acetate consumption with sediment incubations, the results from co-culture experiments show that syntrophic growth may allow aceticlastic methanogens to co-exist with sulfate-reducing bacteria in anoxic, sulfate-rich marine environments....

  5. Performance of concrete after 10 years of exposure in the Arctic marine environment

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, M.H. [National University of Singapore (Singapore); Bilodeau, A.; Malhotra, V.M. [Natural Resources Canada, Ottawa, ON (Canada)

    2001-07-01

    A study was conducted to test the service life of concrete that has been exposed to an Arctic marine environment for 10 years. A total of 12 concrete panels were installed at a site at Nanisivik, Baffin Island, Northwest Territories, Canada. Six of the panels were made with normal-weight aggregate concrete, the others with concrete mixed with expanded shale lightweight aggregate. Steel fibres were also in the cement and the portland cement was replaced with fly ash, slag, silica fume or a combination of fly ash and silica fume. The panels were then visually inspected and cores were also taken to determine the chloride content at various depths from the exposure surface. It was shown that after 10 years of exposure, the panel made of normal weight aggregate did not show much loss of mass from ice abrasion. However, panels made with lightweight aggregate showed mass loss, particularly on the surfaces exposed to the tidal zone. Less damage and cracking was observed in the steel fibre-reinforced panels. Mixtures with fly ash, slag or silica fume showed better resistance to chloride penetration. The use of normal weight limestone aggregate or expanded shale lightweight aggregate did not make a difference in the resistance of the concrete to chloride-ion penetration for non-fibre-reinforced portland cement concrete, but a difference was noted for fibre-reinforced portland cement concrete. Those made with lightweight aggregate materials exhibited a lower chloride-ion content. 7 refs., 10 tabs., 19 figs.

  6. The Behaviour of 134Cs, 60Co, and 85Sr Radionuclides in Marine Environmental Sediment

    Directory of Open Access Journals (Sweden)

    Nariman H.M. Kamel

    2002-01-01

    Full Text Available This work describes experimental investigations and modelling studies on the sorption of radionuclides 134Cs, 60Co, and 85Sr by certain marine sediments within Egypt. The chemical composition of the marine sediments was determined. The soluble salts were measured for the sediments and the concentrations of the released cations, Al3+, Fe3+, and Si4+, were measured for the sediment materials in 0.1 M NaClO4 aqueous solution at different hydrogen ion concentrations. The two main factors that control the uptake of the radionuclides onto the sediment are the pH and the exchangeable capacities of the sediment materials. Surface complex model was used to estimate the surface charge densities and the electric surface potential of the marine sediment materials. These two parameters were calculated at the surface capacity sites of the sediment materials. The desorption of the adsorbed cations was determined by means of selective consecutive extraction tests using different chemical reagents including (1 1 M MgCl2 (pH 7, (2 1 M ammonium oxalate (pH 3-5, (3 0.04 M NH2OH,HCl in 25% acetic acid (pH 3-4, (4 H2O2 in 5% HNO3(pH 2-3, and (5 digestion with nitric acid followed by hydrofluoric and perchloric acids (pH 2.

  7. The microbial nitrogen cycling potential in marine sediments is impacted by polyaromatic hydrocarbon pollution

    Directory of Open Access Journals (Sweden)

    Nicole M Scott

    2014-03-01

    Full Text Available During petroleum hydrocarbon exposure the composition and functional dynamics of marine microbial communities are altered, favoring bacteria that can utilize this rich carbon source. Initial exposure of high levels of hydrocarbons in aerobic surface sediments can enrich growth of heterotrophic microorganisms having hydrocarbon degradation capacity. As a result, there can be a localized reduction in oxygen potential, if the sediments are aerobic, within the surface layer of marine sediments resulting in anaerobic zones. We hypothesized that increasing exposure to elevated hydrocarbon concentrations would positively correlate with an increase in denitrification processes and the net accumulation of dinitrogen. This hypothesis was tested by comparing the relative abundance of genes associated with nitrogen metabolism and nitrogen cycling identified in 6 metagenomes from sediments contaminated by polyaromatic hydrocarbons from the Deepwater Horizon oil spill in the Gulf of Mexico, and 3 metagenomes from sediments associated with natural oil seeps in the Santa Barbara Channel. An additional 8 metagenomes from uncontaminated sediments from the Gulf of Mexico were analyzed for comparison. We predicted relative changes in metabolite turnover as a function of the differential microbial gene abundances, which showed predicted accumulation of metabolites associated with denitrification processes, including anammox, in the contaminated samples compared to uncontaminated sediments, with the magnitude of this change being positively correlated to the hydrocarbon concentration and exposure duration. These data highlight the potential impact of hydrocarbon inputs on N cycling processes in marine sediments and provide information relevant for system scale models of nitrogen metabolism in affected ecosystems.

  8. Evaluation of the Polyethylene Reverse Sampler as a Dosing System in Marine Phase II Whole Sediment Toxicity Identification Evaluations (TIEs)

    Science.gov (United States)

    Contaminated marine sediments can cause acute and chronic impairments to benthic organisms. Nonionic organic contaminants (NOCs) are often a primary cause of impairment. Toxicity Identification Evaluations (TIEs) are used to identify chemicals causing toxicity in sediments. Ph...

  9. Comparative analysis of land, marine, and satellite observations of methane in the lower Atmosphere in the Russian Arctic under conditions of climate change

    Science.gov (United States)

    Anisimov, O. A.; Kokorev, V. A.

    2015-12-01

    Land, marine, and satellite observations have been used to study changes in methane concentrations in the lower atmosphere during the warm months of the year (July through October) in Arctic regions having different potentials for methane production. The Atmospheric Infrared Sounder (AIRS) data for 2002-2013 are used to explore the interplay between local methane sources in the terrestrial region of the Eurasian Arctic and on the Arctic shelf over the warm period of the year. Linear trends in atmospheric methane concentrations over different Arctic regions are calculated, and a hypothesis of the relation of concentration variations to climatic parameters is tested. The combination of land, marine, and satellite observation is used to develop a conceptual model of the atmospheric methane field in the terrestrial part of the Russian Arctic and on the Arctic shelf. It is shown that the modern methane growth rate in the Arctic does not exceed the Northern Hemisphere mean. It is concluded that the methane emission in the Arctic has little effect on global climate compared to other factors.

  10. Pollution of the Marine Environment by Dumping: Legal Framework Applicable to Dumped Chemical Weapons and Nuclear Waste in the Arctic Ocean

    Directory of Open Access Journals (Sweden)

    Lott, Alexander

    2016-06-01

    Full Text Available The Arctic seas are the world’s biggest dumping ground for sea-disposed nuclear waste and have served among the primary disposal sites for chemical warfare agents. Despite of scientific uncertainty, the Arctic Council has noted that this hazardous waste still affects adversely the Arctic marine environment and may have implications to the health of the Arctic people. The purpose of this manuscript is to establish the rights and obligations of the Arctic States in connection with sea-dumped chemical weapons and nuclear material under international law of the sea, international environmental law and disarmament law. Such mapping is important for considering options to tackle the pollution to the Arctic ecosystems and because there seems to be yet no such analysis across the legal fields carried out. This paper aims first at identifying the scale and approximate locations of sea-disposed nuclear waste and chemical weapons in the Arctic Ocean. The analysis will further focus on ascertaining the possibilities to minimize their adverse effects on the Arctic marine environment under the applicable legal framework. It will be argued in this manuscript that due to the corrosion of the chemical weapons and nuclear material containers, recovering, rather than confining this hazardous waste might be counterproductive as it might cause a sudden and widespread release of chemical agents or radionuclides when surfacing. In this regard, carrying out an environmental impact assessment prior to each such remediation operation would be necessary to determine the most suitable technique for minimizing or eliminating pollution.

  11. Pollution of the Marine Environment by Dumping: Legal Framework Applicable to Dumped Chemical Weapons and Nuclear Waste in the Arctic Ocean

    Directory of Open Access Journals (Sweden)

    Lott, Alexander

    2015-06-01

    Full Text Available The Arctic seas are the world’s biggest dumping ground for sea-disposed nuclear waste and have served among the primary disposal sites for chemical warfare agents. Despite of scientific uncertainty, the Arctic Council has noted that this hazardous waste still affects adversely the Arctic marine environment and may have implications to the health of the Arctic people. The purpose of this manuscript is to establish the rights and obligations of the Arctic States in connection with sea-dumped chemical weapons and nuclear material under international law of the sea, international environmental law and disarmament law. Such mapping is important for considering options to tackle the pollution to the Arctic ecosystems and because there seems to be yet no such analysis across the legal fields carried out. This paper aims first at identifying the scale and approximate locations of sea-disposed nuclear waste and chemical weapons in the Arctic Ocean. The analysis will further focus on ascertaining the possibilities to minimize their adverse effects on the Arctic marine environment under the applicable legal framework. It will be argued in this manuscript that due to the corrosion of the chemical weapons and nuclear material containers, recovering, rather than confining this hazardous waste might be counterproductive as it might cause a sudden and widespread release of chemical agents or radionuclides when surfacing. In this regard, carrying out an environmental impact assessment prior to each such remediation operation would be necessary to determine the most suitable technique for minimizing or eliminating pollution.

  12. Feasibility study of chemical stabilization of dredged marine sediment

    OpenAIRE

    FURLAN, Ana Paola; RAZAKAMANANTSOA, Andry; Liang, Yingjie; Deneele, Dimitri

    2015-01-01

    Chemical stabilization is one of techniques which can improve mechanical and hydraulic properties of dredged sediments. This paper presents an experimental study focused on different techniques of stabilization of dredged sediment from La Baule-Le Pouliguen (France). Dredged sediments are stabilized with lime, Portland cement and fly ash. Three mixes were produced and submitted to uniaxial compression strength (UCS), indirect tensile strength (ITS) and shear tests at different curing ages. In...

  13. Persistent organic pollutant and mercury concentrations in eggs of ground-nesting marine birds in the Canadian high Arctic.

    Science.gov (United States)

    Peck, Liam E; Gilchrist, H Grant; Mallory, Conor D; Braune, Birgit M; Mallory, Mark L

    2016-06-15

    We collected eggs of eight marine bird species from several colony sites in the Canadian high Arctic located at approximately 76°N and analyzed them for concentrations of legacy persistent organic pollutants (POPs) and mercury. We provide the first report on concentrations of POPs in eggs of three Arctic species (Thayer's gull Larus thayeri, Sabine's gull Xema sabini, Ross's Gull Rhodostethia rosea), and we found significant differences in each of the POP profiles among the five species with sufficient data for statistical comparisons (Thayer's gull, black guillemot Cepphus grylle, Sabine's gull, Arctic tern Sterna paradisaea and common eider Somateria mollissima borealis). The Ross's Gull had unexpectedly high POP concentrations relative to the other species examined, although this was based on a single egg, while glaucous gull Larus hyperboreus eggs from our sampling location had very low POPs. Sabine's gulls had the lowest Hg of the eggs studied, consistent with their low trophic position, but concentrations of their legacy POPs were higher than expected. We also noted that total hexachlorocyclohexanes were higher than reported elsewhere in the circumpolar Arctic in three species. PMID:26971212

  14. Tracing carbon flow in an arctic marine food web using fatty acid-stable isotope analysis.

    Science.gov (United States)

    Budge, S M; Wooller, M J; Springer, A M; Iverson, S J; McRoy, C P; Divoky, G J

    2008-08-01

    Global warming and the loss of sea ice threaten to alter patterns of productivity in arctic marine ecosystems because of a likely decline in primary productivity by sea ice algae. Estimates of the contribution of ice algae to total primary production range widely, from just 3 to >50%, and the importance of ice algae to higher trophic levels remains unknown. To help answer this question, we investigated a novel approach to food web studies by combining the two established methods of stable isotope analysis and fatty acid (FA) analysis--we determined the C isotopic composition of individual diatom FA and traced these biomarkers in consumers. Samples were collected near Barrow, Alaska and included ice algae, pelagic phytoplankton, zooplankton, fish, seabirds, pinnipeds and cetaceans. Ice algae and pelagic phytoplankton had distinctive overall FA signatures and clear differences in delta(13)C for two specific diatom FA biomarkers: 16:4n-1 (-24.0+/-2.4 and -30.7+/-0.8 per thousand, respectively) and 20:5n-3 (-18.3+/-2.0 and -26.9+/-0.7 per thousand, respectively). Nearly all delta(13)C values of these two FA in consumers fell between the two stable isotopic end members. A mass balance equation indicated that FA material derived from ice algae, compared to pelagic diatoms, averaged 71% (44-107%) in consumers based on delta(13)C values of 16:4n-1, but only 24% (0-61%) based on 20:5n-3. Our estimates derived from 16:4n-1, which is produced only by diatoms, probably best represented the contribution of ice algae relative to pelagic diatoms. However, many types of algae produce 20:5n-3, so the lower value derived from it likely represented a more realistic estimate of the proportion of ice algae material relative to all other types of phytoplankton. These preliminary results demonstrate the potential value of compound-specific isotope analysis of marine lipids to trace C flow through marine food webs and provide a foundation for future work. PMID:18481094

  15. Verrucomicrobia Are Candidates for Polysaccharide-Degrading Bacterioplankton in an Arctic Fjord of Svalbard

    OpenAIRE

    Cardman, Z.; C. Arnosti; Durbin, A.; Ziervogel, K.; Cox, C; A. D. Steen; Teske, A

    2014-01-01

    In Arctic marine bacterial communities, members of the phylum Verrucomicrobia are consistently detected, although not typically abundant, in 16S rRNA gene clone libraries and pyrotag surveys of the marine water column and in sediments. In an Arctic fjord (Smeerenburgfjord) of Svalbard, members of the Verrucomicrobia, together with Flavobacteria and smaller proportions of Alpha- and Gammaproteobacteria, constituted the most frequently detected bacterioplankton community members in 16S rRNA gen...

  16. PAST Gateways (Palaeo-Arctic Spatial and Temporal Gateways): Introduction and overview

    Science.gov (United States)

    Ó Cofaigh, Colm; Briner, Jason P.; Kirchner, Nina; Lucchi, Renata G.; Meyer, Hanno; Kaufman, Darrell S.

    2016-09-01

    This special issue relates to the Second International Conference of the PAST Gateways (Palaeo-Arctic Spatial and Temporal Gateways) network which was held in Trieste, Italy in 2014. Twenty five papers are included and they address topics under four main themes: (1) The growth and decay of Arctic ice sheets; (2) Arctic sea ice and palaeoceanography; (3) Terrestrial Arctic environments and permafrost change; and (4) Holocene Arctic environmental change. Geographically the focus is circum-Arctic; the special issue includes detailed regional studies from Greenland, Scandinavia, Russia, and Arctic North America and the adjoining seas, as well as a series of synthesis-type, review papers on Fennoscandian Ice Sheet deglaciation and Holocene Arctic palaeo-climate change. The methodologies employed are diverse and include marine sediment core and geophysical investigations, terrestrial glacial geology and geomorphology, isotopic analysis of ground ice, palaeo-ecological analysis of lacustrine and terrestrial sedimentary archives, geochronology and numerical ice sheet modeling.

  17. The use of the Novosol process for the treatment of polluted marine sediment.

    Science.gov (United States)

    Zoubeir, Lafhaj; Adeline, Saliceto; Laurent, Cohen Solal; Yoann, Coudray; Truc, Huynh Trung; Benoît, Le Guen; Federico, Anguoni

    2007-09-30

    The work presented in this article concerns polluted marine sediments. The article is divided into three parts. The first part discusses existing industrial procedures of treatment. The second part introduces the Novosol((R)) process, which was used for the treatment of polluted marine sediments. This process is based on the stabilization of heavy metals in the solid matrix by phosphatation and the destruction of organic matter by calcination. Finally, after a comparison had been made between environmental results obtained on both polluted marine sediments and inert ones, treated sediments were introduced in the production of clay bricks. The results obtained show that the Novosol process leads to the immobilization of most heavy metals and can be considered as an efficient tool for the stabilisation of polluted marine sediment. Thus, the results of physical and mechanical tests as compressive strength and water absorption indicate that performances obtained were comparable to standard brick values. These results confirm that, once treated, polluted sediments can be recycled. PMID:17459577

  18. Natural thorium isotopes in marine sediment core off Labuan port

    Energy Technology Data Exchange (ETDEWEB)

    Hafidz, B. Y.; Asnor, A. S.; Terence, R. C.; Mohamed, C. A. R. [School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600, Bangi, Selangor (Malaysia)

    2014-02-12

    Sediment core was collected from Labuan port and analyzed to determine the radioactivity of thorium (Th) isotopes. The objectives of this study are to determine the possible sources of Th isotopes at Labuan port and estimates the sedimentation rate based on {sup 228}Th/{sup 232}Th model. The results suggest the {sup 230}Th and {sup 232}Th might be originated from terrestrial sedimentary rock while {sup 228}Th originated by authigenic origin. High ratio value of {sup 230}Th/{sup 232}Th detected at the top surface sediment indicates the increasing of {sup 230}Th at the recent years which might be contributed from the anthropogenic sources. The sedimentation rate of core sediment from Labuan Port was successfully estimated by using {sup 228}Th/{sup 232}Th model. The result show high sedimentation rate with 4.67 cm/year indicates rapid deposition occurred at this study area due to the high physical activity at the Labuan port. By assume the constant sedimentation rate at this area; we estimated the age of 142 cm core sediment obtained from Labuan port is 32 years started from 1981 to 2012. This chronology will be used in forthcoming research to investigate the historical profile of anthropogenic activities affecting the Labuan port.

  19. High bacterial biodiversity increases degradation performance of hydrocarbons during bioremediation of contaminated harbor marine sediments

    International Nuclear Information System (INIS)

    We investigated changes of bacterial abundance and biodiversity during bioremediation experiments carried out on oxic and anoxic marine harbor sediments contaminated with hydrocarbons. Oxic sediments, supplied with inorganic nutrients, were incubated in aerobic conditions at 20 °C and 35 °C for 30 days, whereas anoxic sediments, amended with organic substrates, were incubated in anaerobic conditions at the same temperatures for 60 days. Results reported here indicate that temperature exerted the main effect on bacterial abundance, diversity and assemblage composition. At higher temperature bacterial diversity and evenness increased significantly in aerobic conditions, whilst decreased in anaerobic conditions. In both aerobic and anaerobic conditions, biodegradation efficiencies of hydrocarbons were significantly and positively related with bacterial richness and evenness. Overall results presented here suggest that bioremediation strategies, which can sustain high levels of bacterial diversity rather than the selection of specific taxa, may significantly increase the efficiency of hydrocarbon degradation in contaminated marine sediments. - Highlights: ► Bioremediation performance was investigated on hydrocarbon contaminated sediments. ► Major changes in bacterial diversity and assemblage composition were observed. ► Temperature exerted the major effect on bacterial assemblages. ► High bacterial diversity increased significantly biodegradation performance. This should be considered for sediment remediation by bio-treatments. - Bioremediation strategies which can sustain high levels of bacterial diversity may significantly increase the biodegradation of hydrocarbons in contaminated marine sediments.

  20. A Potential Impact on the Chemical Composition in the Marine Boundary Layer in the Arctic Ocean by Ship Emissions

    Science.gov (United States)

    Xie, Z.; Wang, X.; Blum, J. D.; Sun, L.

    2005-12-01

    Samples of aerosols in the marine boundary layer (MBL) of the Arctic Ocean were collected aboard R/V ()Xuelong during the summer on the Second Chinese Arctic Research Expedition (July-September, 2003). Chemical compositions including major and trace elements and polycyclic aromatic hydrocarbons (PAHs) in aerosol particles were analyzed. Results showed that significant amounts of S, Fe, V and Ni are emitted from ship diesel engines and contaminate the ambient air. The total amount of Fe, which plays a significant role in the ocean ()biological pump, emitted from ships in the Arctic is estimated at 4.33-A106 kg yr-1. Sulfur emitted into the atmosphere may be transformed to sulfur acid and result in a chlorine depletion in sea-salt. Because the global inventory of sulfur from ship exhausts is large and halogens may have important consequences in possible tropospheric ozone destruction, the role of ships in effecting halogen depression in sea-salt should be evaluated. For organic compounds, 17 PAHs including Fluoranthene, Phenanthrene, Chrysene, Indeno[123-cd]pyrene, Pyrene, Benzo[b]fluoranthene, Benzo[ghi]pyrene, Naphthalene, Benzo[a]anthracene, Benzo[k]fluoranthene, Coronene, Fluorene, Benzo[a]pyrene, Acenaphthene, Anthracene, Dibenzo[a,h]anthracene and Acenaphthylene were detected. The average levels of subspecies of PAHs in ambient air ranged from 0.003 to 0.089 ng/m3. Among the 17 PAHs, fluoranthene had a relative high level, while the level of acenaphthylene was relative low. The aerosols contaminated by the ship, which were commonly excluded in previous investigations, thus provide an opportunity to investigate and understand the role of ship emissions in the atmospheric chemistry of the marine boundary layer, especially in the Arctic Ocean.

  1. Response of Methanogens in Arctic Sediments to Temperature and Methanogenic Substrate Availability.

    Directory of Open Access Journals (Sweden)

    Lynsay I Blake

    Full Text Available Although cold environments are major contributors to global biogeochemical cycles, comparatively little is known about their microbial community function, structure, and limits of activity. In this study a microcosm based approach was used to investigate the effects of temperature, and methanogenic substrate amendment, (acetate, methanol and H2/CO2 on methanogen activity and methanogen community structure in high Arctic wetlands (Solvatnet and Stuphallet, Svalbard. Methane production was not detected in Stuphallet sediment microcosms (over a 150 day period and occurred within Solvatnet sediments microcosms (within 24 hours at temperatures from 5 to 40°C, the maximum temperature being at far higher than in situ maximum temperatures (which range from air temperatures of -1.4 to 14.1°C during summer months. Distinct responses were observed in the Solvatnet methanogen community under different short term incubation conditions. Specifically, different communities were selected at higher and lower temperatures. At lower temperatures (5°C addition of exogenous substrates (acetate, methanol or H2/CO2 had no stimulatory effect on the rate of methanogenesis or on methanogen community structure. The community in these incubations was dominated by members of the Methanoregulaceae/WCHA2-08 family-level group, which were most similar to the psychrotolerant hydrogenotrophic methanogen Methanosphaerula palustris strain E1-9c. In contrast, at higher temperatures, substrate amendment enhanced methane production in H2/CO2 amended microcosms, and played a clear role in structuring methanogen communities. Specifically, at 30°C members of the Methanoregulaceae/WCHA2-08 predominated following incubation with H2/CO2, and Methanosarcinaceaeand Methanosaetaceae were enriched in response to acetate addition. These results may indicate that in transiently cold environments, methanogen communities can rapidly respond to moderate short term increases in temperature, but

  2. Response of Methanogens in Arctic Sediments to Temperature and Methanogenic Substrate Availability.

    Science.gov (United States)

    Blake, Lynsay I; Tveit, Alexander; Øvreås, Lise; Head, Ian M; Gray, Neil D

    2015-01-01

    Although cold environments are major contributors to global biogeochemical cycles, comparatively little is known about their microbial community function, structure, and limits of activity. In this study a microcosm based approach was used to investigate the effects of temperature, and methanogenic substrate amendment, (acetate, methanol and H2/CO2) on methanogen activity and methanogen community structure in high Arctic wetlands (Solvatnet and Stuphallet, Svalbard). Methane production was not detected in Stuphallet sediment microcosms (over a 150 day period) and occurred within Solvatnet sediments microcosms (within 24 hours) at temperatures from 5 to 40°C, the maximum temperature being at far higher than in situ maximum temperatures (which range from air temperatures of -1.4 to 14.1°C during summer months). Distinct responses were observed in the Solvatnet methanogen community under different short term incubation conditions. Specifically, different communities were selected at higher and lower temperatures. At lower temperatures (5°C) addition of exogenous substrates (acetate, methanol or H2/CO2) had no stimulatory effect on the rate of methanogenesis or on methanogen community structure. The community in these incubations was dominated by members of the Methanoregulaceae/WCHA2-08 family-level group, which were most similar to the psychrotolerant hydrogenotrophic methanogen Methanosphaerula palustris strain E1-9c. In contrast, at higher temperatures, substrate amendment enhanced methane production in H2/CO2 amended microcosms, and played a clear role in structuring methanogen communities. Specifically, at 30°C members of the Methanoregulaceae/WCHA2-08 predominated following incubation with H2/CO2, and Methanosarcinaceaeand Methanosaetaceae were enriched in response to acetate addition. These results may indicate that in transiently cold environments, methanogen communities can rapidly respond to moderate short term increases in temperature, but not

  3. Rare earth elements distribution in marine sediments of Malaysia coasts

    Institute of Scientific and Technical Information of China (English)

    Rezaee; Ebrahim; Saraee; Khadijeh; Saion; B.Elias; Abdul; Khalik; Wood; Abdi; Mohammad; Reza

    2009-01-01

    In the east coast Peninsular Malaysia region,sediments are transported by several rivers from the east Malaysia into the South China Sea estuary.In the vicinity of the five river estuaries core sediments were collected in order to investigate rare earth elements(REEs) profile.Core sediments were divided into strata of between 2 to 4 cm intervals and prepared for analyzing by ICP-AES.REE concentrations of 54.3 μg/gr at 24-26 cm in EC4 increased to 114.1 μg/gr at 20-22 cm in EC5.The measured concentration of ...

  4. The Scientific and Societal Need for Accurate Global Remote Sensing of Marine Suspended Sediments

    Science.gov (United States)

    Acker, James G.

    2006-01-01

    Population pressure, commercial development, and climate change are expected to cause continuing alteration of the vital oceanic coastal zone environment. These pressures will influence both the geology and biology of the littoral, nearshore, and continental shelf regions. A pressing need for global observation of coastal change processes is an accurate remotely-sensed data product for marine suspended sediments. The concentration, delivery, transport, and deposition of sediments is strongly relevant to coastal primary production, inland and coastal hydrology, coastal erosion, and loss of fragile wetland and island habitats. Sediment transport and deposition is also related to anthropogenic activities including agriculture, fisheries, aquaculture, harbor and port commerce, and military operations. Because accurate estimation of marine suspended sediment concentrations requires advanced ocean optical analysis, a focused collaborative program of algorithm development and assessment is recommended, following the successful experience of data refinement for remotely-sensed global ocean chlorophyll concentrations.

  5. Atmospheric mercury over the marine boundary layer observed during the third China Arctic Research Expedition

    Institute of Scientific and Technical Information of China (English)

    Hui Kang; Zhouqing Xie

    2011-01-01

    TGM measurements on board ships have proved to provide valuable complementary information to measurements by a ground based monitoring network.During the third China Arctic Research Expedition (from July 11 to September 24,2008),TGM concentrations over the marine boundary layer along the cruise path were in-situ measured using an automatic mercury vapor analyzer.Here we firstly reported the results in Japan Sea,North Western Pacific Ocean and Bering Sea,where there are rare reports.The value ranged between 0.30 and 6.02 ng/m3 with an average of (1.52 ± 0.68) ng/m3,being slightly lower than the background value of Northern Hemisphere (1.7 ng/m3).Notably TGM showed considerably spatial and temporal variation.Geographically,the average value of TGM in Bering Sea was higher than those observed in Japan Sea and North Western Pacific Ocean.In the north of Japan Sea TGM levels were found to be lower than 0.5 ng/m3 during forward cruise and displayed obviously diurnal cycle,indicating potential oxidation of gaseous mercury in the atmosphere.The pronounced episode was recorded as well.Enhanced levels of TGM were observed in the coastal regions of southern Japan Sea during backward cruise due primarily to air masses transported from the adjacent mainland reflecting the contribution from anthropogenic sources.When ship returned back and passed through Kamchatka Peninsula TGM increased by the potential contamination from volcano emissions.

  6. Formation of natural gas hydrates in marine sediments 1. Conceptual model of gas hydrate growth conditioned by host sediment properties

    Science.gov (United States)

    Clennell, M.B.; Hovland, M.; Booth, J.S.; Henry, P.; Winters, W.J.

    1999-01-01

    The stability of submarine gas hydrates is largely dictated by pressure and temperature, gas composition, and pore water salinity. However, the physical properties and surface chemistry of deep marine sediments may also affect the thermodynamic state, growth kinetics, spatial distributions, and growth forms of clathrates. Our conceptual model presumes that gas hydrate behaves in a way analogous to ice in a freezing soil. Hydrate growth is inhibited within fine-grained sediments by a combination of reduced pore water activity in the vicinity of hydrophilic mineral surfaces, and the excess internal energy of small crystals confined in pores. The excess energy can be thought of as a "capillary pressure" in the hydrate crystal, related to the pore size distribution and the state of stress in the sediment framework. The base of gas hydrate stability in a sequence of fine sediments is predicted by our model to occur at a lower temperature (nearer to the seabed) than would be calculated from bulk thermodynamic equilibrium. Capillary effects or a build up of salt in the system can expand the phase boundary between hydrate and free gas into a divariant field extending over a finite depth range dictated by total methane content and pore-size distribution. Hysteresis between the temperatures of crystallization and dissociation of the clathrate is also predicted. Growth forms commonly observed in hydrate samples recovered from marine sediments (nodules, and lenses in muds; cements in sands) can largely be explained by capillary effects, but kinetics of nucleation and growth are also important. The formation of concentrated gas hydrates in a partially closed system with respect to material transport, or where gas can flush through the system, may lead to water depletion in the host sediment. This "freeze-drying" may be detectable through physical changes to the sediment (low water content and overconsolidation) and/or chemical anomalies in the pore waters and metastable

  7. Vertical distribution of 137Cs activity concentration in marine sediments at Amvrakikos Gulf, western of Greece

    International Nuclear Information System (INIS)

    The aim of the present work is the study of 137Cs migration in sediment column taking into account the sedimentation rate in the Amvrakikos Gulf, at the western part of Greece. Marine core sediments were collected and the measurements were performed using the high resolution gamma-ray spectrometry method. The vertical distribution of 137Cs activity concentration, as part of anthropogenic marine radioactivity, provided averaged sedimentation rate by identifying the depths of activity concentrations due to the Chernobyl accident and the nuclear tests signals. Furthermore, 137Cs measurements were reproduced using the proposed one-dimensional diffusion–advection model which provides mainly as an output, the sedimentation rate and the average diffusivity of 137Cs in the sediment column. The proposed model estimates the temporal variation of 137Cs activity concentration from 1987 (one year after the Chernobyl accident) till today (2014). - Highlights: • Two sediment cores were studied using 137Cs as a tracer. • Two peaks are observed due to nuclear tests and Chernobyl accident. • Diffusivities, as well as 137Cs apparent sedimentation speeds are estimated

  8. An improved electroelution method for separation of DNA from humic substances in marine sediment DNA extracts.

    Science.gov (United States)

    Kallmeyer, Jens; Smith, David C

    2009-07-01

    We present a method for the rapid and simple extraction of DNA from marine sediments using electroelution. It effectively separates DNA from compounds, including humic substances, that interfere with subsequent DNA quantification and amplification. After extraction of the DNA from the sediment into an aqueous solution, the crude sample is encased in 2% agarose gel and exposed to an electrical current, which draws the DNA out of the gel into a centrifugal filter vial. After electroelution, the sample is centrifuged to remove contaminants method is quantitative and does not discriminate on the basis of size, as determined using DNA standards and DNA extracts from environmental samples. Amplification of DNA is considerably improved due to removal of PCR inhibitors. For Archaea, only these purified extracts yielded PCR products. This method allows for the use of relatively large volumes of sediment and is particularly useful for sediments containing low biomass such as deeply buried marine sediments. It works with both organic-rich and -poor sediment, as well as with sediment where calcium carbonate is abundant and sediment where it is limited; consequently, adjustment of protocols is unnecessary for samples with very different organic and mineral contents.

  9. Radiometric dating of sediment records in Kuwait's marine area

    International Nuclear Information System (INIS)

    Six sediment cores collected from the Northwestern Arabian/Persian Gulf have been radiometrically dated by 210Pb. Three cores were collected from stations within the Kuwait Bay, and three others were collected from stations outside the bay. Two models have been used for 210Pb dating of sediment cores, i.e. Constant Flux: Constant Sedimentation (CF:CS) Model and the Constant Rate of Supply (CRS) Model. The average rates were found to vary significantly between 0.16 and 1.00 cm y-1 for stations outside and within the bay respectively. The variability of the sedimentation rate was essentially physiographic characteristics and variable hydrodynamic condition. In this study, 137Cs fallout radiotracer was also used to construct a realistic chronology. It was observed that the 137Cs in the entire vertical profile has been continuously contributed by fluvial and atmospheric deposition. (author)

  10. Evaluation of the toxicity of organic matter in marine sediments

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.

    . The variation of the inhibition of AChE is attributed to the presence of the residues of various neurotoxic substances in the sediment contaminatEd. by the river runoff as well industrial effluents and sewage....

  11. Evaluation of the toxicity of organic matter in marine sediments

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.

    . The variation of the inhibition of AChE is attributed to the presence of the residues of various neurotoxic substances in the sediment contaminatEd. by the river runoff as well industrial effluents and sewage...

  12. Arsenic in marine sediments from French Mediterranean ports: Geochemical partitioning, bioavailability and ecotoxicology

    OpenAIRE

    Mamindy-Pajany, Yannick; Hurel, Charlotte; Geret, Florence; Galgani, Francois; Battaglia-Brunet, Fabienne; Marmier, Nicolas; Romeo, Michele

    2013-01-01

    This work investigates arsenic mobility, bioavailability and toxicity in marine port sediments using chemical sequential extraction and laboratory toxicity tests. Sediment samples were collected from two different Mediterranean ports, one highly polluted with arsenic and other inorganic and organic pollutants (Estaque port (EST)), and the other one, less polluted, with a low arsenic content (Saint Mandrier port (SM)). Arsenic distribution in the solid phase was studied using a sequential extr...

  13. Electric currents couple spatially separated biogeochemical processes in marine sediment

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter; Risgaard-Petersen, Nils; Fossing, Henrik;

    2010-01-01

    in the sediment was driven by electrons conducted from the anoxic zone. A distinct pH peak in the oxic zone could be explained by electrochemical oxygen reduction, but not by any conventional sets of aerobic sediment processes. We suggest that the electric current was conducted by bacterial nanowires combined...... with pyrite, soluble electron shuttles and outer-membrane cytochromes. Electrical communication between distant chemical and biological processes in nature adds a new dimension to our understanding of biogeochemistry and microbial ecology....

  14. Marine and ice landscapes of the Arctic and Sub-arctic in the course of towering industrial activity: ability of the management with using documentation facilities of satellite ecological criminalistics

    Science.gov (United States)

    Melentyev, Vladimir; Vladimirovich Melentyev, Konstantin; Petterssen, Lasse Herbert; Andreevna Zakharova, Tatiana

    2013-04-01

    In our studies we are following for the classification of the marine and ice landscapes of the Arctic that was suggested by prof. Ye.S. Korotkevich who had provided summarizing results of the long-term in situ field experiments and airborne studies that was fulfilled by scientists of Arctic and Antarctic Research Institute (AARI) under his leadership in Russian Arctic after the 2-nd World War. But satellite multispectral observations show significant temporal and spatial modification of the suggested scheme especially for Arctic ice landscapes that had occurred in nowadays due to the climate change and anthropogenic press. Design main principle and rules of satellite ecological criminalistics - science of crime detection of ecocatastrophe and incidents on sea and fresh waters with using aerospace survey as well for the control, for the management and the preventing of ecological instability of the marine and lakes ecosystems was done by Academician Kirill Kondratiev together with his apprentices and follower in 1970-s. In frame proposed paper we shall present results of our comprehensive satellite-airborne studies of the marine and ice landscapes as well discuss the incidents that happened in Arctic inside the inland and international waters in past and present days and were revealed with using multispectral remote sensing. But for all that we need to mention that our contemporary investigations are based on the all-weather satellite ERS-1/2 - Envisat - RADARSAT SAR survey archived since 1990-s by SUAI and NERSC/NIERSC.

  15. Ecotoxicological sediment evaluations in marine aquaculture areas of Chile.

    Science.gov (United States)

    Rudolph, Anny; Medina, Paulina; Urrutia, Carolina; Ahumada, Ramón

    2009-08-01

    Given its geographic characteristics, the southern Chilean fjord area is subjected to growing environmental pressure from the development of diverse forms of aquaculture (i.e., fish, algae, shellfish). The sediments accumulate substances as a natural sink, and ecotoxicology assays offer a reliable and robust proxy for sediment quality analyses. This study's objective was to establish a mid-range toxicity base line for the sediments in the region by applying a battery of non-specific ecotoxicological assays. Sediment samples (28) were collected in the channels and fjords studied during the CIMAR-Fiordos 11 cruise (July 2005). The sediments were evaluated using different species endemic to the eastern Pacific as targets: Ampelisca araucana, Tisbe longicornis, Arbacia spatuligera, and Dunaliella tertiolecta. The conditions for each assay were reported previously. Of the four species used as ecotoxicological tools, only D. tertiolecta differed significantly from the control group (negative) in terms of its growth. This difference could be attributed to nutrient enrichment. In general, we concluded that, although local changes occurred in the sediments, the mesoscale magnitude of the ecotoxicological alterations was small. Nonetheless, a surveillance program should be implemented that would allow us to follow-up and analyze the changes that are taking place in the systems on broader scales of time and space. PMID:18633720

  16. Magnetic fingerprint in marine sediments: clues from cultivated Magnetovibrio blakemorei and recent cores from Brazilian Coast

    Science.gov (United States)

    Jovane, L.; Florindo, F.; Bazylinski, D. A.; Pellizari, V. H.; Brandini, F. P.; de Almeida, L. A.; Carneiro, F. R.; Braga, E. D.; Lins, U.

    2013-12-01

    The magnetic properties (first order reversal curves, ferromagnetic resonance and decomposition of saturation remanent magnetization acquisition) of Magnetovibrio blakemorei strain MV-1, a marine magnetotactic bacterium, differ from those of other magnetotactic species from sediments deposited in lakes and marine habitats previously studied. This finding suggests that magnetite produced by some magnetotactic bacteria retains magnetic properties in relation to the crystallographic structure of the magnetic phase produced and thus might represent a 'magnetic fingerprint' for a specific magnetotactic bacterium. The technique used to determine this fingerprint is a non-destructive, new technology that might allow for the identification and presence of specific species or types of magnetotactic bacteria in certain environments such as sediment. We also show some preliminary results on the biogeochemical factors that control magnetotactic bacterial populations, documenting the environment and the preservation of bacterial magnetite, which dominates the palaeomagnetic signal throughout recent sediments from Brazilian Coast. We searched for magnetotactic bacteria in order to understand the ecosystems and environmental change related to their presence in sediments. We focused on studying the environmental conditions that allow for the presence of magnetotactic bacteria and magnetosomes in sediments including determining magnetotactic bacterial populations in marine settings, measuring crucial nutrient availability in the water column and in sediments, and examining particulate delivery to the seafloor.

  17. Microbiome Dynamics of a Polychlorobiphenyl (PCB) Historically Contaminated Marine Sediment under Conditions Promoting Reductive Dechlorination

    Science.gov (United States)

    Matturro, Bruna; Ubaldi, Carla; Rossetti, Simona

    2016-01-01

    The toxicity of polychlorinated biphenyls (PCB) can be efficiently reduced in contaminated marine sediments through the reductive dechlorination (RD) process lead by anaerobic organohalide bacteria. Although the process has been extensively investigated on PCB-spiked sediments, the knowledge on the identity and metabolic potential of PCB-dechlorinating microorganisms in real contaminated matrix is still limited. Aim of this study was to explore the composition and the dynamics of the microbial communities of the marine sediment collected from one of the largest Sites of National Interest (SIN) in Italy (Mar Piccolo, Taranto) under conditions promoting the PCBs RD. A long-term microcosm study revealed that autochthonous bacteria were able to sustain the PCB dechlorination at a high extent and the successive addition of an external fermentable organic substrate (lactate) caused the further depletion of the high-chlorinated PCBs (up to 70%). Next Generation Sequencing was used to describe the core microbiome of the marine sediment and to follow the changes caused by the treatments. OTUs affiliated to sulfur-oxidizing ε-proteobacteria, Sulfurovum, and Sulfurimonas, were predominant in the original sediment and increased up to 60% of total OTUs after lactate addition. Other OTUs detected in the sediment were affiliated to sulfate reducing (δ-proteobacteria) and to organohalide respiring bacteria within Chloroflexi phylum mainly belonging to Dehalococcoidia class. Among others, Dehalococcoides mccartyi was enriched during the treatments even though the screening of the specific reductive dehalogenase genes revealed the occurrence of undescribed strains, which deserve further investigations. Overall, this study highlighted the potential of members of Dehalococcoidia class in reducing the contamination level of the marine sediment from Mar Piccolo with relevant implications on the selection of sustainable bioremediation strategies to clean-up the site.

  18. Loki's Castle: A sediment-influenced hydrothermal vent field at the ultra-slow spreading Arctic Mid-Ocean Ridge

    Science.gov (United States)

    Baumberger, T.; Frueh-Green, G. L.; Pedersen, R.; Thorseth, I. H.; Lilley, M. D.; Moeller, K.

    2010-12-01

    The chemical composition as well as the stable and radiogenic isotope signatures of hydrothermal fluids from the Loki’s Castle vent field, located at the Mohns-Knipovich bend in the Norwegian-Greenland Sea (73°N), are substantially different from sediment-starved mid-ocean ridge hydrothermal systems. Geochemical studies of the hydrothermal vent fluids and the adjacent rift valley sediments provide insights into the influence of sediments on the hydrothermal fluid composition and provide constraints on acting redox conditions. Additionally, they reflect the degree of fluid-rock-sediment interaction at this arctic hydrothermal vent field. Here we present an overview of the geochemical characteristics of the hydrothermal and sedimentary components at Loki’s Castle, obtained during expeditions in 2008, 2009 and 2010, with emphasis on the stable and radiogenic isotope signatures. We compare these data with other sediment-influenced and sediment-starved mid-ocean ridge hydrothermal systems. The hydrothermal vent fluids are characterized by a pH of ˜ 5.5 and by elevated concentrations of methane, hydrogen and ammonia, which reflect a sedimentary contribution. δ13CDIC (dissolved inorganic carbon) are depleted relative to mantle carbon values, consistent with an organic carbon input. The δ18OH2O values of the vents fluids are enriched compared to background bottom seawater, whereas the δD values are not. 87Sr/86Sr ratios are more radiogenic than those characteristic of un-sedimented mid-ocean ridge vent fluids. S-isotope data reflect mixing of a MORB source with sulphide derived from reduced seawater sulphate. To document the background sediment input of the ridge system, short gravity cores and up to 18 m long piston cores were recovered from various localities in the rift valley. The pore-fluid isotope chemistries of the sediments show vertical gradients that primarily reflect diagenesis and degradation of organic matter. The vertical gradient is locally enhanced

  19. Abiotic racemization kinetics of amino acids in marine sediments.

    Science.gov (United States)

    Steen, Andrew D; Jørgensen, Bo Barker; Lomstein, Bente Aa

    2013-01-01

    The ratios of d- versus l-amino acids can be used to infer the sources and composition of sedimentary organic matter. Such inferences, however, rely on knowing the rates at which amino acids in sedimentary organic matter racemize abiotically between the d- and the l-forms. Based on a heating experiment, we report kinetic parameters for racemization of aspartic acid, glutamic acid, serine, and alanine in bulk sediment from Aarhus Bay, Denmark, taken from the surface, 30 cm, and 340 cm depth below seafloor. Extrapolation to a typical cold deep sea sediment temperature of 3°C suggests racemization rate constants of 0.50×10(-5)-11×10(-5) yr(-1). These results can be used in conjunction with measurements of sediment age to predict the ratio of d:l amino acids due solely to abiotic racemization of the source material, deviations from which can indicate the abundance and turnover of active microbial populations.

  20. The use of ecocores to evaluate biodegradation in marine sediments

    DEFF Research Database (Denmark)

    Jensen, Kurt; Albrechtsen, Hans-Jørgen; Nielsen, Jef;

    1988-01-01

    A laboratory sediment microcosm called the ecocore is described. It has been used to test the biodegradability of substances which predominantly enter the sediment. A new method for introducing hydrophobic test substances such as hydrocarbons to the test system is also described. In a series of...... tests using 14C-labelled hydrocarbons, it has been demonstrated that evolved and trapped 14C02 in all probability reflects the rates of mineralization of the test substance. The fate of the substances within the test system has been described and the total recovery exceeds 80%. The system shows good...

  1. The isotopic composition of authigenic chromium in anoxic marine sediments: A case study from the Cariaco Basin

    OpenAIRE

    Reinhard, Christopher T.; Planavsky, Noah J.; Wang, Xiangli; Fischer, Woodward W.; Johnson, Thomas M.; Lyons, Timothy W.

    2014-01-01

    Chromium (Cr) isotopes are an emerging proxy for tracking redox processes at the Earth's surface. However, there has been limited exploration of the Cr isotope record of modern and recent marine sediments. The basic inorganic chemistry of Cr suggests that anoxic marine basins should factor prominently in the global Cr cycle and that sediments deposited within anoxic basins may offer a valuable Cr isotope archive throughout Earth's history. Here, we present δ^(53)Cr data from sediments of the ...

  2. Soil and Freshwater and Marine Sediment Food Webs: Their Structure and Function

    NARCIS (Netherlands)

    Adams Krumins, J.; van Oevelen, D.; Bezemer, T.M.; de Deyn, G.B.; Hol, W.H.G.; van Donk, E.; de Boer, W.; de Ruiter, P.C.; Middelburg, J.J.; Monroy, F.; Soetaert, K.; Thébault, E.; van de Koppel, J.; van Veen, J.A.; Viketoft, M.; van der Putten, W.H.

    2013-01-01

    The food webs of terrestrial soils and of freshwater and marine sediments depend on adjacent aboveground or pelagic ecosystems for organic matter input that provides nutrients and energy. There are important similarities in the flow of organic matter through these food webs and how this flow feeds b

  3. Microscale spatial distributions of microbes in marine intertidal sediments andphotosynthetic microbial mats

    NARCIS (Netherlands)

    Carreira , C.

    2015-01-01

    Marine sedimentary habitats generally have their highest microbial activity in the top few centimeters. Where light reaches the sediments, benthic oxygenic photoautotrophs grow and the organic matter released is decomposed in a series ofdifferent metabolic pathways by heterotrophic prokaryotes. If g

  4. Quantifying the degradation of organic matter in marine sediments: A review and synthesis

    NARCIS (Netherlands)

    Arndt, S.; Jørgensen, B.B.; LaRowe, D.E.; Middelburg, J.J.; Pancost, R.D.; Regnier, P.

    2013-01-01

    Quantifying the rates of biogeochemical processes in marine sediments is essential for understanding global element cycles and climate change. Because organic matter degradation is the engine behind benthic dynamics, deciphering the impact that various forces have on this process is central to deter

  5. Partition of iodine (129I and 127I) isotopes in soils and marine sediments

    DEFF Research Database (Denmark)

    Hansen, Violeta; Roos, Per; Aldahan, Ala;

    2011-01-01

    environmental mobility is strongly linked to organic matter. Due to its long half-life (15.7 million years), 129I builds up in the environment and can be traced since the beginning of the nuclear era in reservoirs such as soils and marine sediments. Nevertheless, partition of the isotope between the different...

  6. Thermodynamic and kinetic control on anaerobic oxidation of methane in marine sediments

    DEFF Research Database (Denmark)

    Knab, Nina J.; Dale, Andrew W.; Lettmann, Karsten;

    2008-01-01

    The free energy yield of microbial respiration reactions in anaerobic marine sediments must be sufficient to be conserved as biologically usable energy in the form of ATP. Anaerobic oxidation of methane (AOM) coupled to sulfate reduction (SRR) has a very low standard free energy yield of ΔG  = -3...

  7. Characterization of cytotoxic compound from marine sediment derived actinomycete Streptomyces avidinii strain SU4

    Directory of Open Access Journals (Sweden)

    S Sudha

    2012-10-01

    Conclusion: This study clearly proves that the marine sediment derived actinomycetes with bioactive metabolites can be expected to provide high quality biological material for high throughout biochemical and anticancer screening programs. These results help us to conclude that the potential of using metabolic engineering and post genomic approaches to isolate more bioactive compounds and make their possible commercial application is not far off.

  8. Using marine sediment archives to reconstruct past outlet glacier variability

    DEFF Research Database (Denmark)

    Andresen, Camilla Snowman; Straneo, Fiamma; Ribergaard, Mads;

    2013-01-01

    Ice-rafted debris in fjord sediment cores provides information about outlet glacier activity beyond the instrumental time period. It tells us that the Helheim Glacier, Greenland’s third most productive glacier, responds rapidly to short-term (3 to 10 years) climate changes....

  9. The importance of marine sediment biodiversity in ecosystem precesses

    NARCIS (Netherlands)

    Snelgrove, P.V.R.; Blackburn, T.H.; Hutchings, P.; Alongi, D.M.; Grassle, J.F.; Hummel, H.; King, G.; Koike, I.; Lambshead, P.J.D.; Ramsing, N.B.; Solis-Weiss, V.

    1997-01-01

    Sedimentary habitats cover most of the ocean bottom and therefore constitute the largest. single ecosystem on earth in spatial coverage, Although only a small fraction of the micro-, meio- and macroscopic benthic organisms that reside in and on sediments have been described and few estimates of tota

  10. Mineralogical and geochemical aspects of the marine sediments off Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Paropkari, A.L.

    environment caused by impingement of 'oxygen minimum' waters on the floor of the slope between water depths of 120 to 1200m. Phosphate concentrations in sediments are as such not very appreciable; its occurrence as concretions in the core collected from...

  11. Partition of iodine (129I and 127I) isotopes in soils and marine sediments

    International Nuclear Information System (INIS)

    Natural organic matter, such as humic and fulvic acids and humin, plays a key role in determining the fate and mobility of radioiodine in soil and sediments. The radioisotope 129I is continuously produced and released from nuclear fuel reprocessing plants, and as a biophilic element, its environmental mobility is strongly linked to organic matter. Due to its long half-life (15.7 million years), 129I builds up in the environment and can be traced since the beginning of the nuclear era in reservoirs such as soils and marine sediments. Nevertheless, partition of the isotope between the different types of organic matter in soil and sediment is rarely explored. Here we present a sequential extraction of 129I and 127I chemical forms encountered in a Danish soil, a soil reference material (IAEA-375), an anoxic marine sediment from Southern Norway and an oxic sediment from the Barents Sea. The different forms of iodine are related to water soluble, exchangeable, carbonates, oxides as well as iodine bound to humic acid, fulvic acid and to humin and minerals. This is the first study to identify 129I in humic and fulvic acid and humin. The results show that 30-56% of the total 127I and 42-60% of the total 129I are associated with organic matter in soil and sediment samples. At a soil/sediment pH below 5.0-5.5, 127I and 129I in the organic fraction associate primarily with the humic acid while at soil/sediment pH > 6 129I was mostly found to be bound to fulvic acid. Anoxic conditions seem to increase the mobility and availability of iodine compared to oxic, while subaerial conditions (soils) reduces the availability of water soluble fraction compared to subaqueous (marine) conditions. - Highlights: → Chemical speciation of 129I and 127I in soil and sediment. → Association of 129I with humic substances in soil and marine sediments is reported. → Partition of iodine within the organic fraction depends on soil/sediment pH. → Anoxic conditions seem to increase the mobility

  12. usSEABED: Database Efforts in Marine Surficial Sediments of the US EEZ

    Science.gov (United States)

    Reid, J. A.; Jenkins, C. J.; Field, M. E.; Gardner, J. V.; Zimmermann, M.; Box, C. E.; Kneeshaw, T. A.

    2001-12-01

    The USGS, in partnership with the University of Sydney, Australia and National Marine Fisheries Service, Seattle is constructing a unique marine surficial sediment database, usSEABED, for the United States EEZ. usSEABED maximizes the knowledge of the seafloor by combining sedimentological and biological information, verbal sample and photographic descriptions (through fuzzy set theory), chemical, and acoustic data, along with other seabed geologic characteristics, into a single standardized format. In this way, usSEABED is more than a compilation of known quantitative surficial sediment data but rather provides an integrated view of the seabed. Decades of marine sediment research by federal, state, local, academic, and private institutions has provided temporal and spatial snapshots of the ocean floor, either as focused, tightly gridded sampling efforts, or in the earliest days, more widely scattered efforts. As is, these datasets had disparate purposes with dissimilar sampling parameters, statistics, and data types. usSEABED filters these datasets, providing uniform parameters for quantitative sediment textural data, parsed verbal data (using fuzzy set theory), modeled data, and both geologic and biologic compositional parameters. Access to our efforts is through our website, available in the fall of 2001, which includes an explanation of the processing involved, sample maps, an interactive GIS site, and a data-download site. usSEABED is held in a comma-delimited, field-defined, tree-d structure that can be brought into most COTS relational databases or GIS. Focussed originally on the U.S. Pacific margin, recent work is widening the coverage to areas in Hawaii, Alaska, the Gulf of Mexico, the Great Lakes, and the U.S. Atlantic margin. usSEABED is an ongoing project, with expanding data inclusions and new data-filtering modules available, such as sediment true-color displays and marine mineral locations. We invite the additions of new sedimentological, biological

  13. Development and Evaluation of Polychaete Reverse Samplers for Marine Phase II Whole Sediment Toxicitiy Identification Evaluations (TIE)

    Science.gov (United States)

    Marine and estuarine sediments accumulate contaminants and act as a sink for a wide range of toxic chemicals. As a result, the sediments themselves can become a source of contamination. At sufficient levels, contaminated sediments can cause benthic impairments and toxicity to m...

  14. Observation of surface ozone in the marine boundary layer along a cruise through the Arctic Ocean: From offshore to remote

    Science.gov (United States)

    He, Pengzhen; Bian, Lingen; Zheng, Xiangdong; Yu, Juan; Sun, Chen; Ye, Peipei; Xie, Zhouqing

    2016-03-01

    Ozone is an important reactive gas in the troposphere; it has been frequently used to estimate atmospheric oxidation capacity. However, there are few data of surface ozone over the Arctic Ocean, especially the central Arctic Ocean. Here, surface ozone in the marine boundary layer along the cruise path during the 5th Chinese Arctic Research Expedition (June to September, 2012) was investigated. The latitudes and longitudes covered in the cruise were 31.1°N-87.7°N and 9.3°E-90°E-168.4°W. The 1-h-averaged ozone varied from 9.4 ppbv to 124.5 ppbv along the cruise. The highest mixing ratios appeared in the East China Sea and the Sea of Japan while the lowest in the Chukchi Sea. The relatively high ozone levels over the East China Sea, the Sea of Japan, and offshore Iceland were caused by transport of precursors and/or ozone from the nearby continent. Ozone mixing ratio decreasing by ~ 2 ppbv/° with increasing latitude was observed during 31-45°N covering the East China Sea and the Sea of Japan, and during 62-69°N covering offshore Iceland. Over the entire Arctic Ocean, ozone levels were relatively low, varying from 9.4 ppbv to 36.1 ppbv with an average of 23.8 ± 4.6 (mean ± standard deviation) ppbv, which was not statistically different with data observed at Barrow observatory during the same period. Unlike ozone over contaminated areas, a slight increasing trend of ozone in 69-87°N was observed. This phenomenon may be ascribed to the role of both vertical transport and chemical processes due to solar radiation.

  15. Competition within the marine microalgae over the polar dark period in the Greenland Sea of high Arctic

    Institute of Scientific and Technical Information of China (English)

    Zhang Qing; Rolf Gradinger; Zhou Qingsong

    2003-01-01

    With the onset of winter, polar marine microalgae would have faced total darkness for a period of up to 6 months. A natural autumn community of Arctic sea ice microalgae was collected for dark survival experiments from the Greenland Sea during the ARKTIS-XI/2 Expedition of RV Polarstern in October 1995. After a dark period of 161 days, species dominance in the algal assemblage have changed from initially pennate diatoms to small phytoflagellates ( < 20 μm). Over the entire dark period, the mean algal growth rate was - 0.01 d-1. Nearly all diatom species had negative growth rates, while phytoflagellate abundance increased. Resting spore formation during the dark period was observed in less than 4.5% of all cells and only for dinoflagellates and the diatom Chaetoceros spp. We assume that facultative heterotrophy and energy storage are the main processes enabling survival during the dark Arctic winter. After an increase in light intensity, microalgal cells reacted with fast growth within days. Phytoflagellates had the highest growth rate, followed by Nitzschia frigida. Further investigations and experiments should focus on the mechanisms of dark survival (mixotrophy and energy storage) of polar marine microalgae.

  16. Validation of an analytical methodology for the quantitative analysis of petroleum hydrocarbons in marine sediment samples

    Directory of Open Access Journals (Sweden)

    Eloy Yordad Companioni Damas

    2009-01-01

    Full Text Available This work describes a validation of an analytical procedure for the analysis of petroleum hydrocarbons in marine sediment samples. The proposed protocol is able to measure n-alkanes and polycyclic aromatic hydrocarbons (PAH in samples at concentrations as low as 30 ng/g, with a precision better than 15% for most of analytes. The extraction efficiency of fortified sediments varied from 65.1 to 105.6% and 59.7 to 97.8%, for n-alkanes and PAH in the ranges: C16 - C32 and fluoranthene - benzo(apyrene, respectively. The analytical protocol was applied to determine petroleum hydrocarbons in sediments collected from a marine coastal zone.

  17. Instrumental neutron activation analysis of marine sediment in-house reference material

    International Nuclear Information System (INIS)

    Reference materials play an important role in demonstrating the quality and reliability of analytical data. The advantage of using in-house reference materials is that they provide a relatively cheap option as compared to using commercially available certified reference material (CRM) and can closely resemble the laboratory routine test sample. A marine sediment sample was designed as an in-house reference material, in the framework of quality assurance and control (QA/QC) program of the Neutron Activation Analysis (NAA) Laboratory at Nuclear Malaysia. The NAA technique was solely used for the homogeneity test of the marine sediment sample. The CRM of IAEA- Soil 7 and IAEA- SL1 (Lake Sediment) were applied in the analysis as compatible matrix based reference materials for QA purposes. (Author)

  18. Long distance electron transport in marine sediments: Microbial and geochemical implications

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Larsen, Steffen; Pfeffer, Christian;

    and promotes the formation of Mg-calcite and iron oxides in the oxic zone. Oxygen seems to be the major electron acceptor, and more than 40% of the oxygen consumption in sediments can be driven by long distance electron transfer from distant electron donors. The major e-donor is sulfide, which is oxidized......Anaerobic oxidation of organic matter in marine sediment is traditionally considered to be coupled to oxygen reduction via a cascade of redox processes and transport of intermittent electron donors and acceptors. Electric currents have been found to shortcut this cascade and directly couple...... to sulfate, and iron sulphides are the major sources for sulfide in the system. Procaryotes with the ability to perform long distance electron transmission may flourishes in marine sediments exposed to transient oxygen depletion, leaving distinct signatures of such events in the geological record....

  19. Optimization of hard clams, polychaetes, physical disturbance and denitrifying bacteria of removing nutrients in marine sediment.

    Science.gov (United States)

    Shen, Hui; Thrush, Simon F; Wan, Xihe; Li, Hui; Qiao, Yi; Jiang, Ge; Sun, Ruijian; Wang, LiBao; He, Peimin

    2016-09-15

    Marine organisms are known to play important roles in transforming nutrients in sediments, however, guidelines to optimize sediment restoration are not available. We conducted a laboratory mesocosm experiment to investigate the role of hard clams, polychaetes, the degree of physical disturbance and denitrifying bacterial concentrations in removing total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC) in marine sediments. Response surface methodology was employed to analyze the results of initial experiments and in a subsequent experiment identified optimal combinations of parameters. Balancing the TN, TP, TOC removal efficiency, our model predicted 39% TN removal, 33% TP removal, and 42% TOC removal for a 14-day laboratory bioremediation trial using hard clams biomass of 1.2kgm(-2), physical disturbance depth of 16.4cm, bacterial density of 0.18Lm(-2), and polychaetes biomass of 0.16kgm(-2), respectively. These results emphasize the value of combining different species in field-based bioremediation. PMID:27371956

  20. Sequential Sediment Budgets in an Ungauged Watershed: Redwood Creek, Marin County, California

    Science.gov (United States)

    Downs, P. W.; Stallman, J.

    2005-12-01

    Sediment budgets provide an organizing framework in fluvial geomorphology and have enormous potential in environmental management. A sediment budget approach assisted in developing strategies for restoring Big Lagoon, the wetland ecosystem at the terminus of the 22.7 km2 Redwood Creek watershed in Marin County, California. Persistence of a restored lagoon largely depends on the current sediment yield relative to the reference yield prior to European settlement. Process-based, distributed sediment budgets were constructed for several historical time periods to account for accelerated sediment production from contemporary land management practices and legacy factors stemming from past resource exploitation. Sediment production, storage, and transfer were investigated using digital terrain modeling, field reconnaissance to ascertain and validate hillslope processes, mainstem channel surveys and dendrochronology to assess trends in alluvial sediment storage, application of published process rate estimates, use of short-term and prorated stream gauging records, and sediment transport modeling to validate sediment yields into Big Lagoon. Evidence suggests that the Redwood Creek valley bottom aggraded from at least 3,500 B.P., with floodplain wetlands acting as sediment sinks (average annual sediment yield of 34 t km2 yr-1). Channel incision rapidly followed European settlement and intensive hillslope disturbances beginning around 1840 (peak yield 1921-1982 of 324 t km2 yr-1). Mainstem and large tributary valley bottoms became major sediment sources during this time and remain sources despite progressive retirement of most agricultural land use (yield 1981-2000 of 198 t km2 yr-1). Numerous issues related to data availability and resolution limited quantification of some sediment sources and resulted in potential uncertainties in estimates of yield to Big Lagoon. Historical sediment budgets, however, require more than adequate data sources, they require accurate conceptual

  1. Sedimentation rates and age modeling of Late Quaternary marine sediments with unsupported 230Th

    International Nuclear Information System (INIS)

    230Th is a radionuclide of the 238U decay series, characterized by natural abundance in sediments and a half-life of 75,380 years, suitable for direct evaluation of sedimentation rates and sediment ages in a time scale of 700,000 years before the present. 230Th cycle creates a contrast between supported and unsupported 230Th in the sedimentary matrix due to the different geochemical behaviors of 230Th and its parent, 234U. This study aimed at establishing and validating a mathematical model that evaluates sedimentation rates and age modeling based on 230Th data retrieved from a sediment core sampled in the southeastern Brazilian continental margin. The validation of the age modeling of this method was made through a statistical comparison between its results and those of benthic foraminifera δ 18O record technique, widely used for sediment dating and determination of sedimentation rates. It was observed that the model of unsupported 230Th was successful in determining Late Quaternary sedimentation rates and ages in a confidence level of 95 %. It was possible to determine several breaking points in unsupported 230Th vertical profile, and it was shown that those divides correspond to some major intervals between glacial and interglacial periods when compared with the benthic foraminifera record. (author)

  2. Recent surface marine sediments of Cocos Island in Costa Rica

    Institute of Scientific and Technical Information of China (English)

    Jeffrey A. SIBAJA-CORDERO; Jess S. TRONCOSO; Eddy GMEZ-RAMREZ

    2014-01-01

    Subtidal sediments of Isla del Coco (Cocos Island), Costa Rica were described in their grain size, sorting, organic matter, and carbonates from 27 dredge samples (3-75 m), collected in April 2010. The organic matter range between 1.37-3.31% and carbonates presented a mean of 74±17%. The sorting was moderately or poorly. The grain size ranged between 0.1-1.1mm. The pattern is that sediment change from inner to mouth of bays. Carbonates and gravel fractions increased offshore and organic matter have high values inner the bays. Input of vegetal debris and mud was from the rivers of this island covered with rain and cloud forest.

  3. A theoretical framework of tracer methods for marine sediment dynamics

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new theoretical framework of tracer methods is proposed in the present contribution, on the basis of mass conservation. This model is applicable for both artificial and natural tracers. It can be used to calculate the spatial distribution patterns of sediment transport rate, thus providing independent information and verification for the results derived from empirical formulae. For the procedures of the calculation, first, the tracer concentration and topographic maps of two times are obtained. Then, the spatial and temporal changes in the concentration and seabed elevation are calculated, and the boundary conditions required are determined by field observations (such as flow and bedform migration measurements). Finally, based upon eqs. (1) and (13), the transport rate is calculated and expressed as a function of the position over the study area. Further, appropriate modifications to the model may allow the tracer to have different densities and grain size distributions from the bulk sediment.

  4. Fram-2014/2015: A 400 Day Investigation of the Arctic's Oldest Sediments over the Alpha Ridge with a Research Hovercraft

    Science.gov (United States)

    Hall, J. K.; Kristoffersen, Y.

    2014-12-01

    The thickest multi-year ice in the Arctic covers a secret. Four short cores raised from the Alpha Ridge in the 1970s and 1980s from drift stations T-3 and CESAR showed ages between 45 and 76 my. The reason for these old ages became clear when examination of legacy seismic data from T-3 showed that in some places up to 500 m of sediments had been removed within an area of some 200 by 600 km, presumably by an impact of asteroid fragments. To investigate the impact area, the authors conceived an innovative research platform in 2007. Named the R/H SABVABAA, this 12m by 6m hovercraft has been home-based in Svalbard since June 2008. During the following 6 years the craft and its evolving innovative light-weight equipment have made 18 trips to the summer ice pack, traveling some 4410 km over ice during some six months of scientific investigations. An opportunity to get a lift to this area, some 1500 km from Svalbard, came in a 2011 invitation to join AWI's icebreaker POLARSTERN in its ARK-XXVIII/4 expedition departing Tromsö August 5, 2014. The 400 day drift will be the first wintering over, ever, of a mobile research platform with geophysical, geological, and oceanographic capabilities. The Arctic ice pack continually moves due to winds and currents. While at the main camp, observations will consist of marine geophysics (seismic profiling with four element CHIRP, a 20 in³ airgun with single hydrophone, as well as 12 kHz bathymetry and 200 kHz sounding of the deep scattering layer), marine geology (coring with a hydrostatically-boosted 3 or 6 m corer; bottom photography; and two rock dredges), and oceanography. Deployed away from the camp, four sonobuoys will allow 3-D seismic acquisition. Access to the depths below the ice is via a hydraulic capstan winch, with 6500 m of Kevlar aramid fiber rope with 2.8 ton breaking strength. Ice thickness monitoring of the local 100 km² will be made with the craft's EM-31 probe when away from the camp, moving to choice locations for

  5. TEX86 paleothermometry : proxy validation and application in marine sediments

    OpenAIRE

    C. Huguet

    2007-01-01

    Determination of past sea surface temperature (SST) is of primary importance for the reconstruction of natural climatic changes, modelling of climate and reconstruction of ocean circulation. Recently, a new SST proxy was introduced, the TetraEther indeX of lipids with 86 carbons (TEX86), which is based on temperature-related changes that occur in the composition of creanarchaeotal membrane lipids. An empirical correlation between TEX86 values of sediment core tops from a wide variety of geogr...

  6. Diagenetic imprints on magnetic mineral assemblages in marine sediments

    OpenAIRE

    Garming, Johanna Fredrika Lukina

    2006-01-01

    Sediments and sedimentary rocks are important sources for paleomagnetic studies of the geomagnetic field behaviour and of environmental changes. These studies are greatly dependent on the reliable extraction of the detrital magnetic signal. Overprinting of this signal by reductive diagenetic processes, where iron-bearing minerals are dissolved and secondary (magnetic) sulphide minerals form, jeopardizes the validity of such investigations. It is therefore necessary to be aware of the possible...

  7. Study of photocatalytic degradation of tributyltin, dibutylin and monobutyltin in water and marine sediments.

    Science.gov (United States)

    Brosillon, Stephan; Bancon-Montigny, Chrystelle; Mendret, Julie

    2014-08-01

    This study reports on the first assessment of the treatment of sediments contaminated by organotin compounds using heterogeneous photocatalysis. Photocatalysis of organotins in water was carried out under realistic concentration conditions (μgL(-1)). Degradation compounds were analyzed by GC-ICP-MS; a quasi-complete degradation of tributyltin (TBT) in water (99.8%) was achieved after 30min of photocatalytic treatment. The degradation by photolysis was about (10%) in the same conditions. For the first time decontamination of highly polluted marine sediments (certified reference material and harbor sediments) by photocatalysis proves that the use of UV and the production of hydroxyl radicals are an efficient way to treat organotins adsorbed onto marine sediment despite the complexity of the matrix. In sediment, TBT degradation yield ranged from 32% to 37% after only 2h of irradiation (TiO2-UV) and the by-products: dibutyltin (DBT) and monobutyltin (MBT) were degraded very rapidly in comparison with TBT. It was shown that during photocatalysis of organotins in sediments, the hydroxyl radical attack and photolysis are the two ways for the degradation of adsorbed TBT. PMID:24613444

  8. Luminescence Dating of Marine Terrace Sediments Between Trabzon and Rize, Eastern Black Sea Basin: Preliminary Results

    Science.gov (United States)

    Softa, Mustafa; Spencer, Joel Q. G.; Emre, Tahir; Sözbilir, Hasan; Turan, Mehmet

    2016-04-01

    Quaternary marine terraces in the coastal region of Pontides in Northeastern Turkey are valuable archives of past sea level change. Until recently, dates of raised marine terraces undeciphered in the coastal region between Trabzon and Rize because of chronologic limitations. In this paper was to determine ages of the terrace deposits by applying optically stimulated luminescence (OSL) dating methods using single aliquot regenerative dose (SAR) techniques on quartz minerals from extracted marine terraces. Several samples were collected from three orders of Quaternary marine terraces which are reproducible at all sampling location in between cities of Trabzon and Rize, Turkey, coastal of Eastern Pontides, at the front of the thrust system. The terrace deposits mainly consist of clays, silts, sands and gravels. The sediments in these deposits are mainly derived from basaltic, andesitic, and limestone geology, and have elipsoid, square and flat shapes. The terrace deposits have heights ranging from 1 to 17 meters and increases in height and thickness from west to east. Initial OSL results from 1 mm and 3 mm quartz aliquots demonstrate good luminescence characteristics. Preliminary equivalent dose analysis results ranging from 17.6 Gy to 79.6 Gy have been calculated using the Central Age Model (CAM) and Minimum Age Model (MAM). According to ages obtained from three separate terrace is ~8 ka, ~42 ka and ~78 ka, respectively. Results of marine terrace sediments indicate this region has three sedimentation periods and coastal region of Pontides has been remarkably tectonically active since latest Pleistocene to earlier Holocene. This study will present preliminary OSL dating results obtained from samples of Quaternary marine terrace formation. Keywords: optically stimulated luminescence (OSL) dating, single grain, marine terraces, Eastern Pontides.

  9. Abiotic racemization kinetics of amino acids in marine sediments.

    Directory of Open Access Journals (Sweden)

    Andrew D Steen

    Full Text Available The ratios of d- versus l-amino acids can be used to infer the sources and composition of sedimentary organic matter. Such inferences, however, rely on knowing the rates at which amino acids in sedimentary organic matter racemize abiotically between the d- and the l-forms. Based on a heating experiment, we report kinetic parameters for racemization of aspartic acid, glutamic acid, serine, and alanine in bulk sediment from Aarhus Bay, Denmark, taken from the surface, 30 cm, and 340 cm depth below seafloor. Extrapolation to a typical cold deep sea sediment temperature of 3°C suggests racemization rate constants of 0.50×10(-5-11×10(-5 yr(-1. These results can be used in conjunction with measurements of sediment age to predict the ratio of d:l amino acids due solely to abiotic racemization of the source material, deviations from which can indicate the abundance and turnover of active microbial populations.

  10. Marine sediment toxicity identification evaluation methods for the anionic metals arsenic and chromium.

    Science.gov (United States)

    Burgess, Robert M; Perron, Monique M; Cantwell, Mark G; Ho, Kay T; Pelletier, Marguerite C; Serbst, Jonathan R; Ryba, Stephan A

    2007-01-01

    Marine sediments accumulate a variety of contaminants and, in some cases, demonstrate toxicity because of this contamination. Toxicity identification evaluation (TIE) methods provide tools for identifying the toxic chemicals causing sediment toxicity. Currently, whole-sediment TIE methods are not available for anionic metals like arsenic and chromium. In the present paper, we describe two new anion-exchange resins used in the development of whole-sediment TIE methods for arsenic and chromium. Resins were shown to reduce whole-sediment toxicity and overlying water concentrations of the anionic metals. Sediment toxicity, expressed as the median lethal concentration, was reduced by a factor of two to a factor of nearly six between amended sediment treatments containing resin and those without resin. Aqueous concentrations of arsenic and chromium in the toxicity exposures decreased to less than the detection limits or to concentrations much lower than those measured in treatments without resin. Interference studies indicated that the anion-exchange resins had no significant effect on concentrations of the representative pesticide endosulfan and minimal effects on concentrations of ammonia. However, the anion-exchange resins did significantly reduce the concentrations of a selection of cationic metals (Cd, Cu, Ni, Pb, and Zn). These data demonstrate the utility of anion-exchange resins for determining the contribution of arsenic and chromium to whole-sediment toxicity. The present results also indicate the importance of using TIE methods in a formal TIE structure to ensure that results are not misinterpreted. These methods should be useful in the performance of marine whole-sediment TIEs.

  11. Nucleic acid based quantitative microbial community analysis in different marine and terrestrial sediments

    Science.gov (United States)

    Schippers, A.; Blazejak, A.; Köweker, G.

    2009-12-01

    Sub-seafloor sediments harbour over half of all prokaryotic cells on Earth. This immense cell number is calculated from numerous microscopic cell counts (AODC) in ODP sediment cores. Since AODC can not differentiate between living or dead cells, the population size of living microorganisms and the abundance of different prokaryotic groups are unknown. Recent molecular nucleic acid and biomarker analyses showed that a high proportion of the cells are alive and that the microbial communities of deep marine sediments harbour members of distinct, uncultured bacterial and archaeal lineages. The main objective of our project is the quantification of living prokaryotes in various sediments. Deep sediment samples from the Pacific and the Atlantic Oceans (ODP Legs 201 and 207, IODP Exp. 307 and 308), sediments from the Indian Ocean (RV Sonne 189-2) and the Black Sea (RV Meteor 51/4) as well as terrestrial Chesapeake Bay Sediments (ICDP) were analyzed using Catalyzed Reporter Deposition - Fluorescence In Situ Hybridisation (CARD - FISH) and quantitative, real-time PCR (Q-PCR), targeting either the 16S rRNA gene or the functional genes dsrA, mcrA and aprA to quantify microorganisms of various phylogenetic or physiological groups (e.g. JS1 cluster and Chloroflexi). At all sediment sites, cell numbers decreased with depth, however, the abundance of particular microbial groups varied at different sites and depths. The results indicate that global estimates of the deep biosphere should be reconsidered.

  12. Toxicological effects of short-term resuspension of metal-contaminated freshwater and marine sediments.

    Science.gov (United States)

    Fetters, Kyle J; Costello, David M; Hammerschmidt, Chad R; Burton, G Allen

    2016-03-01

    Sediments in navigation-dominated waterways frequently are contaminated with a variety of particle-associated pollutants and are subject to frequent short-term resuspension events. There is little information documenting whether resuspension of metal-contaminated sediments has adverse ecological effects on resident aquatic organisms. Using a novel laboratory approach, the authors examined the mobilization of Zn, Cu, Cd, Pb, Ni, and Cr during resuspension of 1 freshwater and 2 coastal marine sediments and whether resuspension and redeposition resulted in toxicity to model organisms. Sediment flux exposure chambers were used to resuspend metal-contaminated sediments from 1 site in Lake DePue, Illinois (USA), and 2 sites in Portsmouth Naval Shipyard, Maine (USA). Short-term (4-h) resuspension of sediment at environmentally relevant suspended particulate matter concentrations (Daphnia magna; survival, growth, and tissue metal concentration of Neanthes arenaceodentata; bioluminescence of Pyrocystis lunula) was observed during 4-h exposure to resuspended sediments and during 4-d to 10-d post-exposure recovery periods in uncontaminated water. Redeposited suspended particles exhibited increased metal bioavailability and toxicity to H. azteca, highlighting the potential for adverse ecological impacts because of changes in metal speciation. It is important to consider interactions between organisms' life histories and sediment disturbance regimes when assessing risks to ecosystems. PMID:26313755

  13. Using marine bioassays to classify the toxicity of Dutch harbor sediments.

    Science.gov (United States)

    Stronkhorst, Joost; Schipper, Cor; Brils, Jos; Dubbeldam, Marco; Postma, Jaap; van de Hoeven, Nelly

    2003-07-01

    A procedure was developed to assess contaminated marine sediments from Dutch harbors for possible adverse biological effects using three laboratory bioassays: A 10-d survival test with the amphipod Corophium volutator, a 14-d survival test with the heart urchin Echinocardium cordatum (adults), and the bioluminescence inhibition test with the bacterium Vibrio fischeri (Microtox solid phase test LSP]). Microtox results were mathematically corrected for the modifying influence of fine sediment particles. After a validation procedure on test performance and modifying factors, respectively, 81%, 99%, and 90% of the amphipod, heart urchin, and Microtox results were approved. Lower and upper threshold limits for biological effects were set at respectively 24 and 30% mortality for C. volutator, 27 and 35% mortality for E. cordatum, and 24 and 48 toxic units for the Microtox SP based on significant differences with control sediment and the performance of reference sediments. The bioassays clearly distinguished harbor sediments that give rise to acute effects and those that do not. Threshold limits for the amphipods, heart urchins, and bacteria were exceeded in, respectively, 9 to 17%, 33 to 40%, and 23 to 50% of the sediment samples. Highest effects were observed in sediments from the northerly harbors; there was significantly less response in sediments from the Delta Region and the port of Rotterdam (The Netherlands). The procedure outlined in this paper can be used for routine screening of contaminated dredged material that is proposed for open water disposal. PMID:12836979

  14. Spatial variability of carbon (δ13C) and nitrogen (δ15N) stable isotope ratios in an Arctic marine food web

    DEFF Research Database (Denmark)

    Hansen, Joan Holst; Hedeholm, Rasmus Berg; Sünksen, Kaj;

    2012-01-01

    Stable isotopes of carbon (δ13C) and nitrogen (δ15N) were used to examine trophic structures in an arctic marine food web at small and large spatial scales. Twelve species, from primary consumers to Greenland shark, were sampled at a large spatial scale near the west and east coasts of Greenland...

  15. Arctic Watch

    Science.gov (United States)

    Orcutt, John; Baggeroer, Arthur; Mikhalevsky, Peter; Munk, Walter; Sagen, Hanne; Vernon, Frank; Worcester, Peter

    2015-04-01

    The dramatic reduction of sea ice in the Arctic Ocean will increase human activities in the coming years. This will be driven by increased demand for energy and the marine resources of an Arctic Ocean more accessible to ships. Oil and gas exploration, fisheries, mineral extraction, marine transportation, research and development, tourism and search and rescue will increase the pressure on the vulnerable Arctic environment. Synoptic in-situ year-round observational technologies are needed to monitor and forecast changes in the Arctic atmosphere-ice-ocean system at daily, seasonal, annual and decadal scales to inform and enable sustainable development and enforcement of international Arctic agreements and treaties, while protecting this critical environment. This paper will discuss multipurpose acoustic networks, including subsea cable components, in the Arctic. These networks provide communication, power, underwater and under-ice navigation, passive monitoring of ambient sound (ice, seismic, biologic and anthropogenic), and acoustic remote sensing (tomography and thermometry), supporting and complementing data collection from platforms, moorings and autonomous vehicles. This paper supports the development and implementation of regional to basin-wide acoustic networks as an integral component of a multidisciplinary, in situ Arctic Ocean Observatory.

  16. Uranium and plutonium in marine sediments; Uranio y plutonio en sedimentos marinos

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Almazan T, M. G. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Ruiz F, A. C., E-mail: eduardo.ordonez@inin.gob.mx [UNAM, Instituto de Ciencias del Mar y Limnologia, Unidad Academica Mazatlan, Sinaloa (MX)

    2011-11-15

    The marine sediments contain uranium concentrations that are considered normal, since the seawater contains dissolved natural uranium that is deposited in the bed sea in form of sediments by physical-chemistry and bio-genetics processes. Since the natural uranium is constituted of several isotopes, the analysis of the isotopic relationship {sup 234}U/{sup 238}U are an indicator of the oceanic activity that goes accumulating slowly leaving a historical registration of the marine events through the profile of the marine soil. But the uranium is not the only radioelement present in the marine sediments. In the most superficial strata the presence of the {sup 239+140}Pu has been detected that it is an alpha emitter and that recently it has been detected with more frequency in some coasts of the world. The Mexican coast has not been the exception to this phenomenon and in this work the presence of {sup 239-140}Pu is shown in the more superficial layers of an exploring coming from the Gulf of Tehuantepec. (Author)

  17. Biogeomorphological implications of microscale interactions between sediment geotechnics and marine benthos: a review

    Science.gov (United States)

    Murray, John M. H.; Meadows, Azra; Meadows, Peter S.

    2002-09-01

    At the foundations of biogeomorphological processes in the sea lie interactions between the activities of marine benthic animals and the geotechnical properties of their sedimentary environments. The potential significance of these interactions, which take place at a microscale level of millimetres to metres, for the large-scale geomorphology of the seabed has rarely been appreciated. In the context of this review, large-scale is defined as greater than 50 m to hundreds of kilometres. The present review addresses this link, drawing examples from a wide range of marine environments, including estuaries, the intertidal zone, continental shelves and slopes, and the deep sea. It firstly considers sediment stabilisation, slope failure, sediment mixing, biodeposition, sediment compaction, and hydrodynamic effects. This is followed by a consideration of two extremes of the ecological pyramid—the effects of marine meiofauna and marine vertebrates. The final section draws attention to the central role of faunal mucus and extracellular polymeric material (ECPM) in many of the microscale interactions that we describe. The implications of these microscale biological processes and features are discussed in terms of their influence on and control of the large-scale geomorphology of the seabed.

  18. Relatively high antibiotic resistance among heterotrophic bacteria from arctic fjord sediments than water - Evidence towards better selection pressure in the fjord sediments

    Science.gov (United States)

    Hatha, A. A. Mohamed; Neethu, C. S.; Nikhil, S. M.; Rahiman, K. M. Mujeeb; Krishnan, K. P.; Saramma, A. V.

    2015-12-01

    The objective of this study was to determine the prevalence of antibiotic resistance among aerobic heterotrophic bacteria and coliform bacteria from water and sediment of Kongsfjord. The study was based on the assumption that arctic fjord environments are relatively pristine and offer very little selection pressure for drug resistant mutants. In order to test the hypothesis, 200 isolates belonging to aerobic heterotrophic bacteria and 114 isolates belonging to coliforms were tested against 15 antibiotics belonging to 5 different classes such as beta lactams, aminoglycosides, quinolones, sulpha drugs and tetracyclines. Resistance to beta lactam and extended spectrum beta lactam (ESBL) antibiotics was considerably high and they found to vary significantly (p antibiotic resistance against ESBL's extent and diversity of antibiotic resistance (as revealed by multiple antibiotic resistance index and resistance patterns), was high in the aerobic heterotrophic bacteria. Most striking observation was that isolates from fjord sediments (both heterotrophic bacteria and coliforms) in general showed relatively high prevalence of antibiotic resistance against most of the antibiotics tested, indicating to better selection pressure for drug resistance mutants in the fjord sediments.

  19. Evaluation of bioremediation potential of three benthic annelids in organically polluted marine sediment.

    Science.gov (United States)

    Ito, Mana; Ito, Katsutoshi; Ohta, Kohei; Hano, Takeshi; Onduka, Toshimitsu; Mochida, Kazuhiko; Fujii, Kazunori

    2016-11-01

    This study aimed to evaluate the possible remedial effects of three marine benthic annelids on organically polluted sediments from the waters of Hatsukaichi Marina, Hiroshima, Japan. Two polychaetes, Perinereis nuntia and Capitella cf. teleta, and an oligochaete, Thalassodrilides sp., were incubated in sediments for 50 days. Their effects on physicochemical properties such as organic matter (loss on ignition), redox potential (Eh), acid volatile sulfides (AVS), and degradation of polycyclic aromatic hydrocarbons (PAHs) were assessed. The polychaetes P. nuntia and C. cf. teleta significantly increased Eh level and decreased AVS level compared with the oligochaete Thalassodrilides sp. and control (without benthic organisms). Total PAH concentration significantly decreased from the initial level with all three groups; Thalassodrilides sp. had a marked ability to reduce PAHs in sediment. These results indicate that benthic organisms have species-specific remediation properties and ecological functions in organically polluted sediments. PMID:27565306

  20. Physical chemical analysis of marine sediment cementation from the Gulf of Guinea

    Science.gov (United States)

    Liu, Xianfeng; Hammad, Tammam; Saiyouri, Nadia; Hattab, Mahdia

    2012-09-01

    This study aims at investigating the cementation of marine sediments from the Gulf of Guinea by using physicochemical analysis. In order to highlight the presence of cementation in the sediments, three conventional consolidation tests were conducted on intact and remoulded samples. Mercury intrusion porosimetry analyses were then carried out on the specimens taken from samples after consolidation tests. Several physicochemical experimental techniques were used to analyze these cementations, such as cation exchange capacity analysis, batch test, scanning electron microscope imaging coupled with EDS chemical analysis, and thermal analysis. The results seem to indicate that the cementation of these sediments is predominated by the presence of smectite gel between clay aggregates (clusters). Finally, a conceptual sediment microstructural model is proposed to describe the cementation.

  1. Environmental and biogeochemical process of accumulation of iron-phosphorus in marine sediments

    Institute of Scientific and Technical Information of China (English)

    WENG Huanxin; ZHANG Xingmao; WU Nengyou; CHEN Lihong; CHEN Jingfeng; WANG Ying; QIN Yachao; TIAN Rongxiang

    2004-01-01

    This paper discusses the environmental and biogeochemical process of accumulation of iron-phosphorus in marine sediments for the north aktian of the South China Sea and analyzes the relationships between the contents of iron, phosphorus and calcium carbonate as well as their existent characteristics. The results show that the variances of phosphorus and calcium carbonate contents with depths are opposite and those of iron and calcium carbonate contents are almost accordant. It is not only related to the biogeochemical process of accumulation of biogenous calcium carbonate in sediments, which resulted from the fact that the marine primary productivity was stimulated by part of terrigenous phosphorus dissolved into seawater due to decline of superficial water temperature and increase of carbon dioxide content in the glacial period, but also related to iron impelled oxidation and accelerated deposit by the dissolved oxygen from the atmosphere and the photosynthesis of hydrophytes in seawater. The variance of soluble iron-phos- phorus species (Fe-P) in sediment columns can sensitively reflect the changes of climate and environment, which suggests that the accumulative characteristics and existent states of iron-phosphorus species (Fe-P) in marine sediments have the significance as an indicator of the changes of paleoclimate and paleoenvironment.

  2. Geochemical analysis of marine sediments using fused glass disc by X-ray fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    XIA Ning; ZHANG Qin; YAO De; LI Guohui

    2008-01-01

    A method was developed for content determination of Na, Mg, Al, Si, P,S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Nb, Zr, Y, Sr, Rb, Ba, La and Ce etc. covering 26 major, minor, and trace elements in marine sediment samples using fused glass disc by X-ray Fluorescence spectrometry. Calibration was made using marine sediment certified reference materials and the synthetic standard samples prepared by mixing several marine sediments with stream sediment and carbonate standard samples in different proportions. The matrix effect was corrected using theoretical alpha coefficients, experience coefficients and the scattered radiation as the internal standard (for the trace elements). The accuracy of the method was evaluated by analysis of certified reference materials GBW07314, GBW07334 and GSMS6. The results are in good agreement with the certified values of the standards with RSD less than 2.60%, except for Y, Cr, Ga, Ce, La, Nb, Rb, and V with RSD less than 9.0% (n=12).

  3. Intercomparison of radionuclide measurements in marine sediment sample IAEA-367

    International Nuclear Information System (INIS)

    The results of an intercomparison exercise on a Pacific Ocean sediment sample, IAEA-367, designed for the determination of artificial and natural radionuclides levels, are reported. The data from 81 laboratories representing 37 countries have been evaluated. The following are the recommended values, with confidence intervals, for 60Co, 90Sr, 137Cs, 239+240Pu (Reference date: 1 January 1990). Information values for 155Eu, 238Pu, 241Am, and 241Pu are reported. Information values for the following natural radionuclides 40K, 226Ra, 228Th, 230Th, 234U, 235U and 238U are also reported. (author)

  4. Intercomparison of radionuclide measurements in marine sediment sample IAEA-368

    International Nuclear Information System (INIS)

    The results of an intercomparison exercise on a Pacific Ocean sediment sample, IAEA-368, designed for the determination of artificial and natural radionuclides levels, are reported. The data from 89 laboratories representing 37 countries have been evaluated. The following are the recommended values, with confidence intervals, for 60Co, 155Eu, 2107Pb, 226Ra, 238U, 238Pu and239+240Pu (Reference date: 1 January 1990). Information values for 40K, 90Sr, 137Cs, 228Th, 230Th, 232Th, 234U, 235U and 241Am are also reported. (author)

  5. Abiotic racemization kinetics of amino acids in marine sediments

    DEFF Research Database (Denmark)

    Steen, Andrew; Jørgensen, Bo Barker; Lomstein, Bente Aagaard

    2013-01-01

    Enantiomeric ratios of amino acids can be used to infer the sources and composition of sedimentary organic matter. Such inferences, however, rely on knowing the rates at which amino acids in sedimentary organic racemize abiotically. Based on a heating experiment, we report Arrhenius parameters...... between different amino acids or depths. These results can be used in conjunction with measurements of sediment age to predict the ratio of D:L amino acids due solely to abiotic racemization of the source material, deviations from which can indicate the abundance and turnover of active microbial...

  6. Dinoflagellate cysts in recent marine sediment from Guangxi,China

    Institute of Scientific and Technical Information of China (English)

    Haifeng Gu; Qi Fang; Jun Sun; Dongzhao Lan; Feng Cai; Zhiyong Gao

    2003-01-01

    Total of 33 species of dinoflagellate cysts were discovered from surface sediment in the searegion of Guangxi, among them 12 cyst types (Diplopsalopsis sp. 1, D. sp.2, D. sp.3, Cochlodiniumsp., Protoperidinium sp. 1, P. sp. 2, P.compressum, Scrippsiella sp. 1, S. sp. 2, Alexandriumsp. 1, A. sp. 2, A. sp. 3) were first reported from the South China Sea. And one cyst type(Cochlodinium sp. ) was first reported in the world. Scrippsiella trochoidea is the dominant species inthis area, accounting for 45 % of all the cysts. There are 2 cysts of toxic dinoflagellate (Alexandriumtamarensis and Gymnodinium catenatum ). But there is no relationship between cyst number and grainsize distribution.

  7. Abiotic Racemization Kinetics of Amino Acids in Marine Sediments

    OpenAIRE

    Steen, Andrew D.; Bo Barker Jørgensen; Bente Aa Lomstein

    2013-01-01

    The ratios of d- versus l-amino acids can be used to infer the sources and composition of sedimentary organic matter. Such inferences, however, rely on knowing the rates at which amino acids in sedimentary organic matter racemize abiotically between the d- and the l-forms. Based on a heating experiment, we report kinetic parameters for racemization of aspartic acid, glutamic acid, serine, and alanine in bulk sediment from Aarhus Bay, Denmark, taken from the surface, 30 cm, and 340 cm depth be...

  8. Cultivation of Autotrophic Ammonia-Oxidizing Archaea from Marine Sediments in Coculture with Sulfur-Oxidizing Bacteria▿ †

    OpenAIRE

    Park, Byoung-Joon; Park, Soo-Je; Yoon, Dae-No; Schouten, Stefan; Sinninghe Damsté, Jaap S.; Rhee, Sung-Keun

    2010-01-01

    The role of ammonia-oxidizing archaea (AOA) in nitrogen cycling in marine sediments remains poorly characterized. In this study, we enriched and characterized AOA from marine sediments. Group I.1a crenarchaea closely related to those identified in marine sediments and “Candidatus Nitrosopumilus maritimus” (99.1 and 94.9% 16S rRNA and amoA gene sequence identities to the latter, respectively) were substantially enriched by coculture with sulfur-oxidizing bacteria (SOB). The selective enrichmen...

  9. Geochemical Screening of Contaminated Marine and Estuarine Sediments

    Science.gov (United States)

    Kruge, M. A.

    2004-05-01

    Waterways near urban centers have been subject to pollution by human activities for centuries. This process greatly intensified with the advent of the Industrial Revolution and the attendant exponential population increase in coastal areas. The co-occurrence of port facilities for ocean-going vessels, large factories, major power generating stations, dense automotive transportation networks, and massive wastewater outfalls, all in compact geographical areas, has produced severe environmental stress. In recent decades, the growing awareness of the seriousness of coastal urban environmental degradation has inspired intensive efforts at pollution prevention and remediation. To better understand pollution dynamics over time in an aquatic urban setting, a program of intensive sampling and analysis leading to the creation of geographic information systems (GIS) would be desirable. Chemical evaluation of sediments for pollution remains a costly and time-consuming procedure, particularly for organic analysis. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) offers a practical alternative for rapid, inexpensive molecular organic analysis, simply employing milligram quantities of dry, whole sediment. The compounds detected comprise an information-rich mixture of thermally extractable components and the products of the thermal decomposition of (bio)polymers present in the sample. These include PAHs, petroleum-derived hopanes, organonitrogen compounds, and linear alkylbenzenes, as illustrated with examples from Long Island Sound and the Passaic River (USA) and Barcelona harbor (Spain).

  10. Worldwide Interlaboratory Comparison on the Determination of Trace Elements in the IAEA-457 Marine Sediment Sample

    International Nuclear Information System (INIS)

    The primary goal of the IAEA Environment Laboratories is to assist Member States in the use of both stable and radioisotope analytical techniques to understand, monitor and protect the environment. In this context, the major impact of large coastal cities on marine ecosystems is an issue of primary concern for the IAEA and the IAEA Environment Laboratories. The marine pollution assessments required to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. Through the IAEA Environment Laboratories, the IAEA has been assisting national laboratories and regional laboratory networks since the early 1970s through the provision of a reference material programme for the analysis of radionuclides, trace elements and organic compounds in marine samples. Quality assurance and quality control are two fundamental requirements to ensure the reliability of analytical results. Data that are not based on adequate quality assurance and quality control can be erroneous, and their misuse can lead to poor environmental management decisions. In this regard, the IAEA has a long history of organizing interlaboratory studies, which have evolved to include an increasing array of potential contaminants in the marine environment. Relevant activities comprise global interlaboratory comparison, regional proficiency tests, the production of marine reference materials and the development of reference methods for trace elements and organic pollutants analysis in marine samples. This publication summarizes the results of the IAEA-457 interlaboratory comparison on the determination of trace elements in a marine sediment sample

  11. Two new Beggiatoa species inhabiting marine mangrove sediments in the Caribbean.

    Directory of Open Access Journals (Sweden)

    Maïtena R N Jean

    Full Text Available Beggiatoaceae, giant sulphur-oxidizing bacteria, are well known to occur in cold and temperate waters, as well as hydrothermal vents, where they form dense mats on the floor. However, they have never been described in tropical marine mangroves. Here, we describe two new species of benthic Beggiatoaceae colonizing a marine mangrove adjacent to mangrove roots. We combined phylogenetic and lipid analysis with electron microscopy in order to describe these organisms. Furthermore, oxygen and sulphide measurements in and ex situ were performed in a mesocosm to characterize their environment. Based on this, two new species, Candidatus Maribeggiatoa sp. and Candidatus Isobeggiatoa sp. inhabiting tropical marine mangroves in Guadeloupe were identified. The species identified as Candidatus Maribeggiatoa group suggests that this genus could harbour a third cluster with organisms ranging from 60 to 120 μm in diameter. This is also the first description of an Isobeggiatoa species outside of Arctic and temperate waters. The multiphasic approach also gives information about the environment and indications for the metabolism of these bacteria. Our study shows the widespread occurrence of members of Beggiatoaceae family and provides new insight in their potential role in shallow-water marine sulphide-rich environments such as mangroves.

  12. Possible impact of decreasing Arctic pack ice on the higher trophic levels: Seabirds and marine mammals

    OpenAIRE

    Joiris, C.R.

    2012-01-01

    Three main aspects of the possible impacts of retreating pack ice and changing ice coverage in the European Arctic on the higher trophic levels are discussed in this chapter: 1. Seabirds are depending on their colonies on land during the breeding season; the main species, e.g. little auk Alle alle, feed in mixed Polar/ Arctic Water in order to bring back food (polar zooplankton) to their chicks on the nest. In case ice coverage is very low, distance between colony and feeding grounds might be...

  13. Magnetotactic bacteria in marine sediments: clues from recent cores from Brazilian Coast

    Science.gov (United States)

    Jovane, L.; Pellizari, V. H.; Brandini, F. P.; Braga, E. D. S.; Freitas, G. R.; Benites, M.; Rodelli, D.; Giorgioni, M.; Iacoviello, F.; Ruffato, D. G.; Lins, U.

    2014-12-01

    The magnetic properties (first order reversal curves, ferromagnetic resonance and decomposition of saturation remanent magnetization acquisition) of marine magnetotactic bacteria, in conjunction with geophysical, geochemical and oceanographic data from the Brazilian Coast, provide interesting insights regarding the primary productivity distribution in oceans. This finding suggests that magnetite produced by some magnetotactic bacteria retains magnetic properties in relation to the crystallographic structure of the magnetic phase produced and thus might represent a "magnetic fingerprint" for the presence of magnetotactic bacteria. The use of those magnetic properties is a non-destructive, new technology that might allow for the identification and presence of specific species or types of magnetotactic bacteria in certain environments such as sediment. We will also show some preliminary results on the biogeochemical factors that control magnetotactic bacterial populations, documenting the environment and the preservation of bacterial magnetite, which dominates the palaeomagnetic signal throughout recent sediments from Brazilian Coast. We searched for magnetotactic bacteria in order to understand the ecosystems and environmental change related to their presence in sediments. We studied magnetotactic bacterial concentration and geophysical, geochemical and oceanographic results in marine settings measuring crucially nutrients availability in the water column and in sediments, on particulate delivery to the seafloor, to understand the environmental condition that allow the presence of magnetotactic bacteria and magnetosomes in sediments.

  14. Exposure of the marine deposit feeder Hydrobia ulvae to sediment associated LAS

    Energy Technology Data Exchange (ETDEWEB)

    Mauffret, A., E-mail: aourell.mauffret@icman.csic.e [Marine Sciences Institute of Andalusia (CSIC), Puerto Real (Cadiz) (Spain); Rico-Rico, A. [Institute for Risk Assessment Sciences, Utrecht University (Netherlands); Temara, A. [The Procter and Gamble Company, Brussels (Belgium); Blasco, J. [Marine Sciences Institute of Andalusia (CSIC), Puerto Real (Cadiz) (Spain)

    2010-02-15

    Linear Alkylbenzene Sulfonates (LAS) effects (mortality, egestion rate, behaviour) on the marine deposit feeder Hydrobia ulvae were assessed in whole-sediment and water-only systems. The results were combined with a bioenergetic-based kinetic model of exposure pathways to account for the observed toxicity. The 10-d LC50 value based on the freely dissolved fraction was 9.3 times lower in spiked sediment (0.152 +- 0.001 (95% CI) mg/L) than in water-only (1.390 +- 0.020 (95% CI) mg/L). Consequently, the actual 10-d LC50 value (208 mg/kg) was overestimated by the Equilibrium Partitioning calculation (1629 mg/kg). This suggests that the sediment associated LAS fraction was bioavailable to the snails. It could also be due to modifications in physiological parameters in absence of sediment, the organism natural substrate. - Lethality of the marine gastropod deposit feeder Hydrobia ulvae exposed to LAS in water-only system was inappropriate to predict LAS toxicity in sediment system.

  15. Organic molecular composition of marine aerosols over the Arctic Ocean in summer: contributions of primary emission and secondary aerosol formation

    Directory of Open Access Journals (Sweden)

    P. Q. Fu

    2012-08-01

    Full Text Available Organic molecular composition of marine aerosol samples collected during the MALINA cruise in the Arctic Ocean was investigated by gas chromatography/mass spectrometry. More than 110 individual organic compounds were determined in the samples and were grouped into different compound classes based on the functionality and sources. The concentrations of total quantified organics ranged from 7.3 to 185 ng m−3 (mean 47.6 ng m−3, accounting for 1.8–11.0% (4.8% of organic carbon in the marine aerosols. Primary saccharides were found to be dominant organic compound class, followed by secondary organic aerosol (SOA tracers formed from the oxidation of biogenic volatile organic compounds (VOCs such as isoprene, α-pinene and β-caryophyllene. Mannitol, the specific tracer for airborne fungal spores, was detected as the most abundant organic species in the samples with a concentration range of 0.052–53.3 ng m−3 (9.2 ng m−3, followed by glucose, arabitol, and the isoprene oxidation products of 2-methyltetrols. Biomass burning tracers such as levoglucosan are evident in all samples with trace levels. On the basis of the tracer-based method for the estimation of fungal-spore OC and biogenic secondary organic carbon (SOC, we estimate that an average of 10.7% (up to 26.2% of the OC in the marine aerosols was due to the contribution of fungal spores, followed by the contribution of isoprene SOC (mean 3.8% and α-pinene SOC (2.9%. In contrast, only 0.19% of the OC was due to the photooxidation of β-caryophyllene. This study indicates that primary organic aerosols from biogenic emissions, both from long-range transport of mid-latitude aerosols and from sea-to-air emission of marine organics, as well as secondary organic aerosols formed from the photooxidation of biogenic VOCs are important factors controlling the organic chemical composition of marine aerosols in the Arctic Ocean.

  16. Organic molecular composition of marine aerosols over the Arctic Ocean in summer: contributions of primary emission and secondary aerosol formation

    Directory of Open Access Journals (Sweden)

    P. Q. Fu

    2013-02-01

    Full Text Available Organic molecular composition of marine aerosol samples collected during the MALINA cruise in the Arctic Ocean was investigated by gas chromatography/mass spectrometry. More than 110 individual organic compounds were determined in the samples and were grouped into different compound classes based on the functionality and sources. The concentrations of total quantified organics ranged from 7.3 to 185 ng m−3 (mean 47.6 ng m−3, accounting for 1.8–11.0% (4.8% of organic carbon in the marine aerosols. Primary saccharides were found to be dominant organic compound class, followed by secondary organic aerosol (SOA tracers formed from the oxidation of biogenic volatile organic compounds (VOCs such as isoprene, α-pinene and β-caryophyllene. Mannitol, the specific tracer for airborne fungal spores, was detected as the most abundant organic species in the samples with a concentration range of 0.052–53.3 ng m−3 (9.2 ng m−3, followed by glucose, arabitol, and the isoprene oxidation products of 2-methyltetrols. Biomass burning tracers such as levoglucosan are evident in all samples with trace levels. On the basis of the tracer-based method for the estimation of fungal-spore OC and biogenic secondary organic carbon (SOC, we estimate that an average of 10.7% (up to 26.2% of the OC in the marine aerosols was due to the contribution of fungal spores, followed by the contribution of isoprene SOC (mean 3.8% and α-pinene SOC (2.9%. In contrast, only 0.19% of the OC was due to the photooxidation of β-caryophyllene. This study indicates that primary organic aerosols from biogenic emissions, both from long-range transport of mid-latitude aerosols and from sea-to-air emission of marine organics, as well as secondary organic aerosols formed from the photooxidation of biogenic VOCs are important factors controlling the organic chemical composition of marine aerosols in the Arctic Ocean.

  17. Biogeochemical Interactions In The Application Of Biotechnological Strategies To Marine Sediments Contaminated With Metals

    Directory of Open Access Journals (Sweden)

    Fonti Viviana

    2015-06-01

    Full Text Available Sediment contamination in coastal areas with high anthropogenic pressure is a widespread environmental problem. Metal contaminants are of particular concern, since they are persistent and cannot be degraded. Microorganisms can influence metal mobility in the sediment by several direct and indirect processes. However, the actual fate of metals in the environment is not easily predictable and several biogeochemical constraints affect their behaviour. In addition, the geochemical characteristics of the sediment play an important role and the general assumptions for soils or freshwater sediments cannot be extended to marine sediments. In this paper we analysed the correlation between metal mobility and main geochemical properties of the sediment. Although the prediction of metal fate in sediment environment, both for ex-situ bioleaching treatments and in-situ biostimulation strategies, appears to require metal-specific and site-specific tools, we found that TOM and pH are likely the main variables in describing and predicting Zn behaviour. Arsenic solubilisation/increase in mobility appears to correlate positively with carbonate content. Cd, Pb and Ni appear to require multivariate and/or non-linear approaches.

  18. OCEANOGRAPHY & MARINE GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20110729 Bai Youcheng(Laboratory of Marine Ecosystem and Biogeochemistry,SOA,Second Institute of Oceanography,Hangzhou 310012,China);Chen Jianfang Biomarker Records in Sediment Core of R12a from the Chukchi Sea during the Last 500 Years(Acta Sedimentologica Sinica,ISSN1000-0550,CN62-1038/P,28(4),2010,p.768-775,6 illus.,40 refs.)Key words:biomarkers,marine sediments,paleoproductivity,Arctic region This paper used multi-biomarkers to study the R12a core’s top 40 cm samples’ phytoplankton and community sampled during the Second Chinese Arctic expedition from the Chukchi Sea in summer,2003,and to obtain the information of the phytoplankton production and community change since 500 a.The results indicate the total and individual primary productivity increased over the last 500 a.The phytoplankton community structure mostly shows the contributions of

  19. Historical trends in persistent organic pollutants and metals recorded in sediment from Lake Ellasjoen, Bjornoya, Norwegian Arctic

    International Nuclear Information System (INIS)

    Ellasjoen receives contaminants from both atmospheric and biological transport (seabird guano). Historical trends of selected persistent organic pollutants and metals were determined by interpretation of down-core contaminant profiles in conjunction with sediment layer ages, determined by the 210Pb method. Polychlorinated biphenyls (PCBs) and dichloro-diphenyl-trichloroethane and metabolites (DDTs) increased from about 1930 until 1970 (max. sum PCBs 71.8 ng/g dry weight (dw), max sum DDTs 4.0 ng/g dw), declining afterwards to 46.4 ng/g dw and 1.6 ng/g dw, respectively. Polybrominated diphenylethers (PBDEs) concentrations are increasing in Ellasjoen, reaching 0.73 ng/g dw in 2001. Hexabromocyclododekane (HBCD) was measured only in sediment from 1-2 cm depth (0.43 and 3.88 ng/g dw of α- and γ-HBCD, respectively). Most metals (As, Cd, Co, Ni and Zn) showed a similar pattern as PCBs. No clear trends were observed for Cr, Pb or V. Mercury (Hg) has increased gradually since the beginning of the industrial era. - Levels of Polybrominated diphenyl ethers are increasing in sediment from a Norwegian, Arctic lake

  20. Historical trends in persistent organic pollutants and metals recorded in sediment from Lake Ellasjoen, Bjornoya, Norwegian Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Evenset, A. [Akvaplan-niva, Polar Environmental Centre, N-9296 Tromso (Norway)]. E-mail: ae@akvaplan.niva.no; Christensen, G.N. [Akvaplan-niva, Polar Environmental Centre, N-9296 Tromso (Norway); Carroll, J. [Akvaplan-niva, Polar Environmental Centre, N-9296 Tromso (Norway); Zaborska, A. [Institute of Oceanology, PAS, Sopot (Poland); Berger, U. [Norwegian Institute for Air Research, Polar Environmental Centre, N-9296 Tromso (Norway); Herzke, D. [Norwegian Institute for Air Research, Polar Environmental Centre, N-9296 Tromso (Norway); Gregor, D. [Gartner Lee Limited, 3 Watson Road South, Suite 1, Guelph, ON N1L 1E3 (Canada)

    2007-03-15

    Ellasjoen receives contaminants from both atmospheric and biological transport (seabird guano). Historical trends of selected persistent organic pollutants and metals were determined by interpretation of down-core contaminant profiles in conjunction with sediment layer ages, determined by the {sup 210}Pb method. Polychlorinated biphenyls (PCBs) and dichloro-diphenyl-trichloroethane and metabolites (DDTs) increased from about 1930 until 1970 (max. sum PCBs 71.8 ng/g dry weight (dw), max sum DDTs 4.0 ng/g dw), declining afterwards to 46.4 ng/g dw and 1.6 ng/g dw, respectively. Polybrominated diphenylethers (PBDEs) concentrations are increasing in Ellasjoen, reaching 0.73 ng/g dw in 2001. Hexabromocyclododekane (HBCD) was measured only in sediment from 1-2 cm depth (0.43 and 3.88 ng/g dw of {alpha}- and {gamma}-HBCD, respectively). Most metals (As, Cd, Co, Ni and Zn) showed a similar pattern as PCBs. No clear trends were observed for Cr, Pb or V. Mercury (Hg) has increased gradually since the beginning of the industrial era. - Levels of Polybrominated diphenyl ethers are increasing in sediment from a Norwegian, Arctic lake.

  1. Validation of an analytical methodology for the quantitative analysis of petroleum hydrocarbons in marine sediment samples

    OpenAIRE

    Eloy Yordad Companioni Damas; Miriam Odette Cora Medina; Ana Catalina Núñez Clemente; Miguel Ángel Díaz Díaz; Luis González Bravo; Rolando Marbot Ramada; Rodny Montes de Oca Porto

    2009-01-01

    This work describes a validation of an analytical procedure for the analysis of petroleum hydrocarbons in marine sediment samples. The proposed protocol is able to measure n-alkanes and polycyclic aromatic hydrocarbons (PAH) in samples at concentrations as low as 30 ng/g, with a precision better than 15% for most of analytes. The extraction efficiency of fortified sediments varied from 65.1 to 105.6% and 59.7 to 97.8%, for n-alkanes and PAH in the ranges: C16 - C32 and fluoranthene - benzo(a)...

  2. Sediment Ksub(d)s and concentration factors for radionuclides in the marine environment

    International Nuclear Information System (INIS)

    Both the biological and geochemical processes, which are dependent on the chemical form of the element in question, and the radioactive decay of the nuclide are important parameters in the models used for the calculation of dumping limits for radioactive wastes disposed of in the deep sea. The geochemical processes were not adequately represented in earlier models and only rough approximations of parameters were used in the calculations. This report provides an approach for the calculation of deep-sea sediment distribution coefficients and coastal sediment concentration factors for radionuclides in marine biological materials based, whenever possible, on field data

  3. Microalgal Photosynthesis and Spectral Scalar Irradiance in Coastal Marine-Sediments of Limfjorden, Denmark

    DEFF Research Database (Denmark)

    LASSEN, C.; PLOUG, H.; JØRGENSEN, BB

    1992-01-01

    Scalar irradiance and oxygenic photosynthesis were measured simultaneously at 100-mum spatial resolution by a fiber-optic scalar irradiance microsensor and an oxygen microelectrode spaced 120 mum apart. Marine microbial mats on sandy sediments along the coast of Limfjorden, Denmark, were dominated...... higher than in the uppermost 0.0-0.6 mm of the sediment. The lower boundary of the euphotic zone (detectable gross photosynthesis) was at a mean light level of greater-than-or-equal-to 7.5 muEinst m-2 s-1....

  4. Intercomparison of radionuclide measurements on marine sediment sample IAEA-300

    International Nuclear Information System (INIS)

    The results of an intercomparison exercise on a sediment from Baltic Sea, IAEA-300, designed for the determination of artificial and natural radionuclides' levels, are reported. The data from 159 laboratories representing 51 countries have been evaluated. The following are the recommended values, with confidence intervals, 40K, 60Co, 125Sb, 134Cs, 137Cs, 155Eu, 210Pb, 210Po, 228Ra, 234U, 238U, 239+240Pu and 241Am. Information values for 54Mn, 90Sr, 226Ra, 228Th, 230Th, 232Th, 235U and 238Pu are also reported. All values are given on the reference date of 1 January 1993 and expressed in Bq kg-1 dry weight. (author)

  5. Corrosion of carbon steel nuclear waste containers in marine sediment

    International Nuclear Information System (INIS)

    The report describes a study of the corrosion of carbon steel nuclear waste containers in deep ocean sediments, which had the objective of estimating the metal allowance needed to ensure that the containers were not breached by corrosion for 1000 years. It was concluded that under such disposal conditions carbon steel would not be subject to localised corrosion or hydrogen embrittlement, and therefore the study concentrated on evaluating the rate of general attack. This was carried out by developing a mechanistically based mathematical model which was formulated on the conservative assumption that the corrosion would be under activation control, and would not be impeded by the formation of corrosion product layers. This model predicted that an allowance of 33 mm would be required for a 1000 year life. (author)

  6. Hyoscyamine-producing marine Actinomycetes from Lagos Lagoon sediment

    Institute of Scientific and Technical Information of China (English)

    Davies; Olabisi; Flora; Adeleye; Isaac; Adeyemi; Wang; Peng; George

    2015-01-01

    Objective:To isolate and screen Actinoniycetes from Lagos Lagoon soil sediments for production of bioactive metabolites.Methods:Sediment samples were collected from four different locations of Lagos Lagoon and were dried for 2 weeks after which the Actinoniycetes were isolated by serial dilution using the spread plate method on starch casein and Kuster’s agar supplemented with 80 ug/mL cycloheximide to prevent fungal growth.The plates were incubated at 28 C for 1-2 weeks.Isolates were selected based on their colonial characteristics as well as their Gram’s reaction and subciiltured using the same media for isolation until pure cultures were obtained and incubated at 28 C for 3 d.Thereafter,they were inoculated into starch casein and Kuster’s broth media and incubated for 8 d.The secondary metabolites were screened for antimicrobial activity against the following microorganisms:methicillin resistant Staphylococcus aureus.Staphylococcus aureus ATCC 29213.Escherichia coli ATCC 29522.Pseudomonas aeruginosa ATCC 27853.Candida albicans and Enterocolitis faecal is ATCC 29212.Coagulasenegative staphylococci isolated from HIV patients were also used(Staphylococcus warneri.Staphylococcus xylosus and Staphylococcus epidennidis).The antimicrobial metabolites of the Actinoniycetes isolates were identified using gas chromatography(GC).Results:Crude extracts of isolates showed antimicrobial activity against some of the test organisms.The GC data analysis showed the antibiotic profile of these isolates.Conclusions:Analysis of the crude extracts of the isolates using GC method,revealed the presence of antibiotics including an anticholinergic hyoscyamine among other conclusions.

  7. Denitrification and Nitrate Reduction to Ammonium in Taihu Lake and Yellow sea Inter—Tidal Marine Sediments

    Institute of Scientific and Technical Information of China (English)

    YINSHIXUE; SHENQIRONG; 等

    1999-01-01

    Denitrification and nitrate reduction to ammonium in Taihu Lake and Yellow Sea inter-tidal marine sediments were studied.The sediment samples were made slurry containing 150g dry matter per liter.Various of glucose-C to nitrate-N.Acetylene inhibition technique was applied to measure denitrification in the slurres,All samples were incubated anaerobically under argon atmosphere,Data showed that Taihu Lake sediment produced more N2O than marine sediment,Denitrification potential was higher in Taihu Lake sediment than in marine one,Glucose added increase denitrification activity but not the denitrification potential of the sediments.Dissimilatory nitrate reduction to ammonium seemed to occur in marine sediment,but not in freshwater one.When the marine sediment was treated with 25mmol L-1 glucose,its denitrification potentail,as indicated by maximum N2O production by acetylene blockage,was lower than that treated with no or 2.5mmol L-1 glucose.Acetylene was suspected to have inhibitory effect on dissimilatory nitrate reduction to ammonium.

  8. Responses in Arctic marine carbon cycle processes: conceptual scenarios and implications for ecosystem function

    Directory of Open Access Journals (Sweden)

    Helen S. Findlay

    2015-04-01

    Full Text Available The Arctic Ocean is one of the fastest changing oceans, plays an important role in global carbon cycling and yet is a particularly challenging ocean to study. Hence, observations tend to be relatively sparse in both space and time. How the Arctic functions, geophysically, but also ecologically, can have significant consequences for the internal cycling of carbon, and subsequently influence carbon export, atmospheric CO2 uptake and food chain productivity. Here we assess the major carbon pools and associated processes, specifically summarizing the current knowledge of each of these processes in terms of data availability and ranges of rates and values for four geophysical Arctic Ocean domains originally described by Carmack & Wassmann (2006: inflow shelves, which are Pacific-influenced and Atlantic-influenced; interior, river-influenced shelves; and central basins. We attempt to bring together knowledge of the carbon cycle with the ecosystem within each of these different geophysical settings, in order to provide specialist information in a holistic context. We assess the current state of models and how they can be improved and/or used to provide assessments of the current and future functioning when observational data are limited or sparse. In doing so, we highlight potential links in the physical oceanographic regime, primary production and the flow of carbon within the ecosystem that will change in the future. Finally, we are able to highlight priority areas for research, taking a holistic pan-Arctic approach.

  9. Arctic Riverine CDOM and its effects on the Polar Marine Light Field

    Energy Technology Data Exchange (ETDEWEB)

    Orandle, Zoe Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Weijer, Wilbert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Elliott, Scott M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wang, Shanlin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-28

    It is well-known that CDOM (Chromophoric Dissolved Organic Matter) can have a significant effect on biological activity in the photic zones of aquatic ecosystems. However, the extent of CDOM’s interference with biological activity is not well-known. We examined this issue in great detail in the mixed surface layer of the Arctic Ocean. We studied the impacts of CDOM’s light attenuation on Arctic phytoplankton populations to discover if riverine CDOM’s presence in the Arctic ocean could inhibit and possibly prevent local phytoplankton populations from performing photosynthesis. We incorporated biogeochemistry concepts and data with oceanographic models and calculations to approach the problem. The results showed that riverine CDOM can indeed significantly impact the productivity of phytoplankton populations during the spring and summer months near the major Arctic river mouths we chose to examine. Although our study was detailed and inclusive of many variables, the issue of CDOM’s light attenuation and its effects on phytoplankton populations must be explored on a global scale to help understand if riverine CDOM could prove disastrous for phytoplankton populations.

  10. Arctic soil development on a series of marine terraces on central Spitsbergen, Svalbard: a combined geochronology, fieldwork and modelling approach

    Science.gov (United States)

    van der Meij, W. Marijn; Temme, Arnaud J. A. M.; de Kleijn, Christian M. F. J. J.; Reimann, Tony; Heuvelink, Gerard B. M.; Zwoliński, Zbigniew; Rachlewicz, Grzegorz; Rymer, Krzysztof; Sommer, Michael

    2016-06-01

    Soils in Arctic regions currently enjoy attention because of their sensitivity to climate change. It is therefore important to understand the natural processes and rates of development of these soils. Specifically, there is a need to quantify the rates and interactions between various landscape- and soil-forming processes. Soil chronosequences are ideal natural experiments for this purpose. In this contribution, we combine field observations, luminescence dating and soil-landscape modelling to improve and test our understanding of Arctic soil formation. The field site is a Holocene chronosequence of gravelly raised marine terraces in central Spitsbergen. Field observations show that soil-landscape development is mainly driven by weathering, silt translocation, aeolian deposition and rill erosion. Spatial soil variation is mainly caused by soil age, morphological position within a terrace and depth under the surface. Luminescence dating confirmed existing radiocarbon dating of the terraces, which are between ˜ 1.5 and ˜ 13.3 ka old. The soil-landscape evolution model LORICA was used to test our hypothesis that the field-observed processes indeed dominate soil-landscape development. Model results additionally indicated the importance of aeolian deposition as a source of fine material in the subsoil for both sheltered and vegetated trough positions and barren ridge positions. Simulated overland erosion was negligible. Consequently, an un-simulated process must be responsible for creating the observed erosion rills. Dissolution and physical weathering both play a major role. However, using present-day soil observations, the relative contribution of physical and chemical weathering could not be disentangled. Discrepancies between field and model results indicate that soil formation is non-linear and driven by spatially and temporally varying boundary conditions which were not included in the model. To conclude, Arctic soil and landscape development appears to be more

  11. Anoxic Transformations of Radiolabeled Hydrogen-Sulfide in Marine and Fresh-Water Sediments

    DEFF Research Database (Denmark)

    ELSGAARD, L.; JØRGENSEN, BB

    1992-01-01

    oxidation to sulfate. Thiosulfate was partly turned over by oxidation or disproportionation and was found to be an intermediate in the (SO4=)-S-35 formation. The results demonstrate that oxidative and reductive sulfur cycling may occur simultaneously in marine and freshwater sediments. When added......Radiolabeled hydrogen sulfide (HS-)-S-35 was used to trace the anoxic sulfur transformations in marine and freshwater sediment slurries. Time course studies consistently showed a rapid (S2O3=)-S-35 formation and a progressive accumulation of (SO4=)-S-35 and thus indicated an anoxic sulfide...... as exogenous oxidant, nitrate (NO3-) stimulated the anoxic sulfide oxidation to sulfate. Ferric iron, added in the form of lepidocrocite (gamma-FeOOH), caused the precipitation of iron sulfides and only partial sulfide oxidation to pyrite and elemental sulfur....

  12. {sup 137}Cs in marine sediments of Admiralty Bay, King George Island, Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Paulo Alves de Lima [Instituto Oceanográfico, Universidade de São Paulo (IO-USP), Pça. do Oceanográfico, 191, Butantã, SP, 05508 900 (Brazil); Ribeiro, Andreza Portella, E-mail: andrezpr@usp.br [Instituto Oceanográfico, Universidade de São Paulo (IO-USP), Pça. do Oceanográfico, 191, Butantã, SP, 05508 900 (Brazil); Mestrado de Gestão Ambiental e Sustentabilidade, Universidade Nove de Julho (UNINOVE), Avenida Francisco Matarazzo, 612, prédio C, andar térreo, Água Branca, São Paulo, SP, 05001 100 (Brazil); Nascimento, Mylene Giseli do; Martins, Cesar de Castro [Centro de Estudos do Mar, Universidade Federal do Paraná (CEM-UFPR), Av. Beira-mar, no number, Balneário Pontal do Sul, Pontal do Paraná, PR, 83255 971 (Brazil); Mahiques, Michel Michaelovitch de; Montone, Rosalinda Carmelo; Figueira, Rubens Cesar Lopes [Instituto Oceanográfico, Universidade de São Paulo (IO-USP), Pça. do Oceanográfico, 191, Butantã, SP, 05508 900 (Brazil)

    2013-01-15

    The radionuclide cesium-137 ({sup 137}Cs) is produced exclusively by anthropogenic processes and primarily by nuclear explosions. This study determined the reference inventory that is {sup 137}Cs associated with the element's original input, and utilized the levels of activity of this radionuclide previously measured in five sediment profiles collected from Admiralty Bay, Antarctica, to investigate the mobility of this element in the environment. {sup 137}Cs has a half-life of 30 years. Because of this, it is environmentally persistent and has been shown to accumulate in marine organisms. The mean reference inventory of this radionuclide in Admiralty Bay sediments, determined using high resolution gamma ray spectrometry, was 20.23 ± 8.94 Bq m{sup −2}, and within the ambient {sup 137}Cs activity range. A model of {sup 137}Cs diffusion–convection was applied to data collected from 1 cm intervals in sediment cores with the aim of providing insights with respect to this element's behavior in sediments. Model results showed a significant correlation between measured and modeled values using the concentrations of {sup 137}Cs, and estimated input into the system from the global fallout of past nuclear tests and expected values based on local sedimentation rates. Results highlight the importance of accounting for the vertical diffusion of {sup 137}Cs in marine sediments when used as a tracer for environmental processes and for assessing potential bioavailability. - Highlights: ► Cesium-137 ({sup 137}Cs) is produced exclusively by anthropogenic processes. ► A model of diffusion–convection simulated {sup 137}Cs environmental behavior. ► This is important for assessing the bioavailability of this toxic element. ► In Antarctica ice cover influenced the input to the sediments.

  13. Quantitative research for pollution levels in marine sediments of Ha Long Bay by nuclear technique

    International Nuclear Information System (INIS)

    Under the theme of Quantitative study of pollution levels in marine sediments of Halong bay by nuclear techniques conducted from June 2011 to June 2013, the authors conducted monitoring, sediment samples collected in the bay below the sediment column at 8 locations, in which 7 columns located at the estuary near Tuan Chau Island and 1 column at the area near the harbor of Cam Pha. The column samples were taken to the laboratory, cut slices with a distance of 2 cm in the form of frozen and conduct tests of radioactive Pb-210 to determine the rate of sediment in the survey area. Evaluation results based on the method by determining 210Pb, the sediment rate showed speed in the survey area ranged from 0.3 cm.a-1 to 1.2 cm.a-1 and an average of 1.0 cm.a-1. The slices of sediment samples (110 samples) were analyzed heavy metals (KLN) and As elemental by ICP-MS method. These sediment sample also were analyzed for simultaneous determination of N and P and total organic carbon (TOC). Results showed that heavy metal concentrations and As is smaller than the value specified in the National Technical Regulation on Sediment Quality of Vietnam (QCVN), phosphorus concentration less than that can cause harmful effects, but the concentration of total nitrogen and organic carbon that may exceed be harmful as directed by Canadian standards (Persuad et al. 1992). The concentration data in the Halong bay sediment were processed by statistical software SPSS-18, results showed high correlation between the quality TOC, N, P, K and correlation the majority of KLN, this proves the origin of sediments is part of the natural soil components and parts (TOC, N, P, K) is due to the activity of human activity as well as by agricultural fertilizers. The average content of elements in sediments Halong be compared with other data published works of sediment Quang Ninh area, the results show the correlation figures are also high. However, the results of the analysis of KLN and As in Halong sediment

  14. Seasonality in contaminant accumulation in Arctic marine pelagic food webs using trophic magnification factor as a measure of bioaccumulation.

    Science.gov (United States)

    Hallanger, Ingeborg G; Warner, Nicholas A; Ruus, Anders; Evenset, Anita; Christensen, Guttorm; Herzke, Dorte; Gabrielsen, Geir W; Borgå, Katrine

    2011-05-01

    Seasonality in biomagnification of persistent organic pollutants (POPs; polychlorinated biphenyls, chlorinated pesticides, and brominated flame retardants) in Arctic marine pelagic food webs was investigated in Kongsfjorden, Svalbard, Norway. Trophic magnification factors (TMFs; average factor change in concentration between two trophic levels) were used to measure food web biomagnification in biota in May, July, and October 2007. Pelagic zooplankton (seven species), fish (five species), and seabirds (two species) were included in the study. For most POP compounds, highest TMFs were found in July and lowest were in May. Seasonally changing TMFs were a result of seasonally changing POP concentrations and the δ¹⁵N-derived trophic positions of the species included in the food web. These seasonal differences in TMFs were independent of inclusion/exclusion of organisms based on physiology (i.e., warm- versus cold-blooded organisms) in the food web. The higher TMFs in July, when the food web consisted of a higher degree of boreal species, suggest that future warming of the Arctic and increased invasion by boreal species can result in increased food web magnification. Knowledge of the seasonal variation in POP biomagnification is a prerequisite for understanding changes in POP biomagnification caused by climate change.

  15. Seasonality in contaminant accumulation in Arctic marine pelagic food webs using trophic magnification factor as a measure of bioaccumulation.

    Science.gov (United States)

    Hallanger, Ingeborg G; Warner, Nicholas A; Ruus, Anders; Evenset, Anita; Christensen, Guttorm; Herzke, Dorte; Gabrielsen, Geir W; Borgå, Katrine

    2011-05-01

    Seasonality in biomagnification of persistent organic pollutants (POPs; polychlorinated biphenyls, chlorinated pesticides, and brominated flame retardants) in Arctic marine pelagic food webs was investigated in Kongsfjorden, Svalbard, Norway. Trophic magnification factors (TMFs; average factor change in concentration between two trophic levels) were used to measure food web biomagnification in biota in May, July, and October 2007. Pelagic zooplankton (seven species), fish (five species), and seabirds (two species) were included in the study. For most POP compounds, highest TMFs were found in July and lowest were in May. Seasonally changing TMFs were a result of seasonally changing POP concentrations and the δ¹⁵N-derived trophic positions of the species included in the food web. These seasonal differences in TMFs were independent of inclusion/exclusion of organisms based on physiology (i.e., warm- versus cold-blooded organisms) in the food web. The higher TMFs in July, when the food web consisted of a higher degree of boreal species, suggest that future warming of the Arctic and increased invasion by boreal species can result in increased food web magnification. Knowledge of the seasonal variation in POP biomagnification is a prerequisite for understanding changes in POP biomagnification caused by climate change. PMID:21312250

  16. Influence of season, location, and feeding strategy on bioaccumulation of halogenated organic contaminants in Arctic marine zooplankton.

    Science.gov (United States)

    Hallanger, Ingeborg G; Ruus, Anders; Herzke, Dorte; Warner, Nicholas A; Evenset, Anita; Heimstad, Eldbjørg S; Gabrielsen, Geir W; Borgå, Katrine

    2011-01-01

    The influence of season, location, feeding strategy, and trophic position on concentration, compositional pattern, and bioaccumulation factors (BAFs) of halogenated organic contaminants (HOCs; polychlorinated biphenyls, chlorinated pesticides, and brominated flame retardants) was investigated within an Arctic zooplankton food web. Water (dissolved fraction) and seven Arctic marine pelagic zooplankton species (including herbivores, omnivores, and predators) were sampled in May, July, and October 2007 at two stations in Kongsfjorden, Svalbard, Norway. The HOC concentrations in both water and zooplankton generally decreased from May to October. The HOC concentrations and patterns among zooplankton species were explained by their feeding strategies, roughly categorized as herbivores, omnivores, and predators, and not stable isotope-derived trophic position. Field-derived BAFs varied greatly, with higher BAFs in May compared with July and October. Furthermore, BAFs differed among the species according to their feeding strategies. The relationship between BAFs from the different seasons and K(OW) (octanol:water partitioning coefficient) showed comparable intercepts and different slopes between May and October, with all relationships diverging from the assumed 1:1 relationship between BAF and K(OW). Differences in HOC concentrations and BAFs from herbivores to predators showed that biomagnification occurred in zooplankton. The results suggest that concentrations and patterns of HOCs in zooplankton species are influenced not only by equilibrium partitioning with water but also by feeding strategy. PMID:20853452

  17. Evaluating spatial patterns of dioxins in sediments to aid determination of potential implications for marine reptiles

    Energy Technology Data Exchange (ETDEWEB)

    Hermanussen, S.; Gaus, C. [National Research Centre for Environmental Toxicology, Brisbane (Australia); Limpus, C.J. [Queensland Environmental Protection Agency, Brisbane (Australia); Paepke, O. [ERGO Forschungsgesellschaft mbH, Hamburg (Germany); Blanshard, W. [Sea World, Gold Coast (Australia); Connell, D. [School of Public Health, Griffith Univ., Brisbane (Australia)

    2004-09-15

    Recent investigations have identified elevated concentrations of polychlorinated dibenzo-p-dioxins (dioxins) in marine sediments and wildlife of Queensland, Australia. While it has been demonstrated that the contamination is widespread and predominantly land-based, limited information exists on the pathways and fate of these compounds within the near-shore marine system. This environment supports unique and threatened species including green sea turtles (Chelonia mydas). Adult green turtles are predominantly herbivorous, feeding on seagrass and algae. Apart from initial migration to feeding grounds (at {proportional_to}10 years of age) and intermittent migrations to breeding grounds (at {proportional_to}30-50 years and thereafter), green turtles remain and feed within relatively small home ranges. Long life-span (50 years or more), near-shore feeding grounds and highly specialized food requirements render green turtles potentially vulnerable to contaminant exposure. Recent studies have shown a relationship between PCDD/F concentrations found in herbivorous marine wildlife and concentrations in sediments of their habitats. Hence, the spatial evaluation of sediment PCDD/F distribution may assist the assessment of green turtle exposure and its potential implications. The present study provides baseline information on green turtle PCDD/F concentrations in Queensland, Australia and investigates exposure pathways. In addition, spatial distribution of PCDD/Fs in sediments from known green turtle feeding regions is assessed using geographic information systems. This represents the first stage of a large scale investigation into the exposure and sensitivity of marine reptiles to dioxins and dioxin-like compounds and to evaluate whether poor health status observed in some populations may be related to contaminant exposure.

  18. Reductive dechlorination of tetrachloroethene in marine sediments: Biodiversity and dehalorespiring capabilities of the indigenous microbes.

    Science.gov (United States)

    Matturro, B; Presta, E; Rossetti, S

    2016-03-01

    Chlorinated compounds pose environmental concerns due to their toxicity and wide distribution in several matrices. Microorganisms specialized in leading anaerobic reductive dechlorination (RD) processes, including Dehalococcoides mccartyi (Dhc), are able to reduce chlorinated compounds to harmless products or to less toxic forms. Here we report the first detailed study dealing with the RD potential of heavy polluted marine sediment by evaluating the biodegradation kinetics together with the composition, dynamics and activity of indigenous microbial population. A microcosm study was conducted under strictly anaerobic conditions on marine sediment collected near the marine coast of Sarno river mouth, one of the most polluted river in Europe. Tetrachloroethene (PCE), used as model pollutant, was completely converted to ethene within 150 days at reductive dechlorination rate equal to 0.016 meq L(-1) d(-1). Consecutive spikes of PCE allowed increasing the degradation kinetics up to 0.1 meq L(-1)d(-1) within 20 days. Strictly anaerobiosis and repeated spikes of PCE stimulated the growth of indigenous Dhc cells (growth yield of ~7.0 E + 07 Dhc cells per μM Cl(-1) released). Dhc strains carrying the reductive dehalogenase genes tceA and vcrA were detected in the original marine sediment and their number increased during the treatment as demonstrated by the high level of tceA expression at the end of the microcosm study (2.41 E + 05 tceA gene transcripts g(-1)). Notably, the structure of the microbial communities was fully described by Catalysed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) as wells as the dynamics of the dechlorinating bacteria during the microcosms operation. Interestingly, a direct role of Dhc cells was ascertained suggesting the existence of strains adapted at salinity conditions. Additionally, non-Dhc Chloroflexi were retrieved in the original sediment and were kept stable over time suggesting their likely flanking role of the RD

  19. Seismic peak amplitude as a predictor of TOC content in shallow marine sediments

    Science.gov (United States)

    Neto, Arthur Ayres; Mota, Bruno Bourguignon; Belem, André Luiz; Albuquerque, Ana Luiza; Capilla, Ramsés

    2016-04-01

    Acoustic remote sensing is a highly effective tool for exploring the seafloor of both deep and shallow marine settings. Indeed, the acoustic response depends on several physicochemical factors such as sediment grain size, bulk density, water content, and mineralogy. The objective of the present study is to assess the suitability of seismic peak amplitude as a predictor of total organic carbon (TOC) content in shallow marine sediments, based on data collected in the Cabo Frio mud belt in an upwelling zone off southeastern Brazil. These comprise records of P-wave velocity (V P) along 680 km of high-resolution single-channel seismic surveys, combined with analyses of grain size, wet bulk density, absolute water content and TOC content for four piston-cores. TOC contents of sediments from 13 box-cores served to validate the methodology. The results show well-defined positive correlations between TOC content and mean grain size (phi scale) as well as absolute water content, and negative correlations with V P, wet bulk density, and acoustic impedance. These relationships yield a regression equation by which TOC content can be satisfactorily predicted on the basis of acoustic impedance for this region: y = - 4.84 ln(x) + 40.04. Indeed, the derived TOC contents differ by only 5% from those determined by geochemical analysis. After appropriate calibration, acoustic impedance can thus be conveniently used as a predictor of large-scale spatial distributions of organic carbon enrichment in marine sediments. This not only contributes to optimizing scientific project objectives, but also enhances the cost-effectiveness of marine surveys by greatly reducing the ship time commonly required for grid sampling.

  20. Metal release from contaminated estuarine sediment under pH changes in the marine environment

    OpenAIRE

    Martin-Torre, C; PAYAN, C; Verbinnen, B; Coz, A.; Ruiz, G.; Vandecasteele, C; Viguri, R

    2015-01-01

    The contaminant release from estuarine sediment due to pH changes was investigated using a modified CEN/TS 14429 pH-dependence leaching test. The test is performed in the range of pH values of 0–14 using deionised water and seawater as leaching solutions. The experimental conditions mimic different circumstances of the marine environment due to the global acidification, carbon dioxide (CO2) leakages from carbon capture and sequestration technologies, and accidental chemical spills in seawater...

  1. Seismic peak amplitude as a predictor of TOC content in shallow marine sediments

    Science.gov (United States)

    Neto, Arthur Ayres; Mota, Bruno Bourguignon; Belem, André Luiz; Albuquerque, Ana Luiza; Capilla, Ramsés

    2016-10-01

    Acoustic remote sensing is a highly effective tool for exploring the seafloor of both deep and shallow marine settings. Indeed, the acoustic response depends on several physicochemical factors such as sediment grain size, bulk density, water content, and mineralogy. The objective of the present study is to assess the suitability of seismic peak amplitude as a predictor of total organic carbon (TOC) content in shallow marine sediments, based on data collected in the Cabo Frio mud belt in an upwelling zone off southeastern Brazil. These comprise records of P-wave velocity ( V P) along 680 km of high-resolution single-channel seismic surveys, combined with analyses of grain size, wet bulk density, absolute water content and TOC content for four piston-cores. TOC contents of sediments from 13 box-cores served to validate the methodology. The results show well-defined positive correlations between TOC content and mean grain size (phi scale) as well as absolute water content, and negative correlations with V P, wet bulk density, and acoustic impedance. These relationships yield a regression equation by which TOC content can be satisfactorily predicted on the basis of acoustic impedance for this region: y = - 4.84 ln( x) + 40.04. Indeed, the derived TOC contents differ by only 5% from those determined by geochemical analysis. After appropriate calibration, acoustic impedance can thus be conveniently used as a predictor of large-scale spatial distributions of organic carbon enrichment in marine sediments. This not only contributes to optimizing scientific project objectives, but also enhances the cost-effectiveness of marine surveys by greatly reducing the ship time commonly required for grid sampling.

  2. 87Sr/86Sr measurements on marine sediments by inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    The application of inductively coupled plasma-mass spectrometry (ICP-MS) is documented for the study of the strontium isotopic composition (87Sr/86Sr) in geological samples, i.e. in the marine lithic fraction of core sediments. Methods for the determination of the isotopic composition, its accuracy and precision are reported. The results obtained simultaneously on 11 samples by both ICP-MS and thermal ionization mass spectrometry (TIMS) reveal a very good correlation (r2 = 0.955). (orig.)

  3. Reductive dechlorination of tetrachloroethene in marine sediments: Biodiversity and dehalorespiring capabilities of the indigenous microbes.

    Science.gov (United States)

    Matturro, B; Presta, E; Rossetti, S

    2016-03-01

    Chlorinated compounds pose environmental concerns due to their toxicity and wide distribution in several matrices. Microorganisms specialized in leading anaerobic reductive dechlorination (RD) processes, including Dehalococcoides mccartyi (Dhc), are able to reduce chlorinated compounds to harmless products or to less toxic forms. Here we report the first detailed study dealing with the RD potential of heavy polluted marine sediment by evaluating the biodegradation kinetics together with the composition, dynamics and activity of indigenous microbial population. A microcosm study was conducted under strictly anaerobic conditions on marine sediment collected near the marine coast of Sarno river mouth, one of the most polluted river in Europe. Tetrachloroethene (PCE), used as model pollutant, was completely converted to ethene within 150 days at reductive dechlorination rate equal to 0.016 meq L(-1) d(-1). Consecutive spikes of PCE allowed increasing the degradation kinetics up to 0.1 meq L(-1)d(-1) within 20 days. Strictly anaerobiosis and repeated spikes of PCE stimulated the growth of indigenous Dhc cells (growth yield of ~7.0 E + 07 Dhc cells per μM Cl(-1) released). Dhc strains carrying the reductive dehalogenase genes tceA and vcrA were detected in the original marine sediment and their number increased during the treatment as demonstrated by the high level of tceA expression at the end of the microcosm study (2.41 E + 05 tceA gene transcripts g(-1)). Notably, the structure of the microbial communities was fully described by Catalysed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) as wells as the dynamics of the dechlorinating bacteria during the microcosms operation. Interestingly, a direct role of Dhc cells was ascertained suggesting the existence of strains adapted at salinity conditions. Additionally, non-Dhc Chloroflexi were retrieved in the original sediment and were kept stable over time suggesting their likely flanking role of the RD

  4. Extension of 239+240Pu sediment geochronology to coarse-grained marine sediments

    Science.gov (United States)

    Kuehl, Steven A.; Ketterer, Michael E.; Miselis, Jennifer L.

    2012-01-01

    Sediment geochronology of coastal sedimentary environments dominated by sand has been extremely limited because concentrations of natural and bomb-fallout radionuclides are often below the limit of measurement using standard techniques. ICP-MS analyses of 239+240Pu from two sites representative of traditionally challenging (i.e., low concentration) environments provide a "proof of concept" and demonstrate a new application for bomb-fallout radiotracers in the study of sandy shelf-seabed dynamics. A kasten core from the New Zealand shelf in the Southern Hemisphere (low fallout), and a vibracore from the sandy nearshore of North Carolina (low particle surface area) both reveal measurable 239+240Pu activities at depth. In the case of the New Zealand site, independently verified steady-state sedimentation results in a 239+240Pu profile that mimics the expected atmospheric fallout. The depth profile of 239+240Pu in the North Carolina core is more uniform, indicating significant sediment resuspension, which would be expected in this energetic nearshore environment. This study, for the first time, demonstrates the utility of 239+240Pu in the study of sandy environments, significantly extending the application of bomb-fallout isotopes to coarse-grained sediments, which compose the majority of nearshore regions.

  5. A novel approach to the assess biotic oxygen consumption in marine sediment communities

    Science.gov (United States)

    Baranov, Victor; Queiros, Ana; Widdicombe, Stephen; Stephens, Nick; Lessin, Gennadi; Krause, Stefan; Lewandowski, Joerg

    2016-04-01

    Bioturbation , the mixing of the sediment matrix by burrowing animals impacts sediment metabolism, including respiration through redistribution of particulate organics, changes in bacterial biota diversity and acitivity, as well as via burrowing fauna's own metabolism. Bioturbation, reflecting faunal activity, is also a proxy for the general sedimentary ecosystem health, and can be impacted by many of emerging marine environmental issues such as ocean acidification, warming and the occurrence of heat waves. Sedimentary oxygen consumption is often taken as a proxy for the activity of bioturbating fauna, but determining baselines can be difficult because of the confounding effects of other fauna and microbes present in sediments, as well as irnorganic processes that consume oxygen. Limitations therefore exist in current methodologies, and numerous confounding factors are hampering progress in this area. Here, we present novel method for the assessment of sediment respiration which is expected to be affected only by the biogenic oxygen consumption (namely aerobic respiration). As long as tracer reduction "immune" to inorganic oxygen consumption, so that measurements using this method can be used, alongside traditional methods, to decouple biological respiration from inorganic oxygen consumption reactions. The tracer is easily detectable, non-toxic and can be applied in systems with constant oxygen supply. The latter allow for incubation without the need to to work with unsealed experimental units, bringing procedural advantage over traditional methods. Consequently assessed bioturbating fauna is not exposed to hypoxia and additional stress. Here, we had applied system for the first time to investigate impacts of a common North-Atlantic bioturbator, the brittle star Amphiura filiformis, - on respiration of marine sediments. Two series of experiments were conducted with animals and sediment collected from Cawsand Bay, Plymouth, UK Preliminary results show that tracer

  6. Examination of the bioaccumulation of halogenated dimethyl bipyrroles in an Arctic marine food web using stable nitrogen isotope analysis.

    Science.gov (United States)

    Tittlemier, Sheryl A; Fisk, Aaron T; Hobson, Keith A; Norstrom, Ross J

    2002-01-01

    Concentrations of four possibly naturally produced organohalogens--1,1'-dimethyl-3,3',4-tribromo-4,5,5'-trichloro-2,2'-bipyrrole (DBP-Br3Cl3), 1,1'-dimethyl-3,3',4,4'-tetrabromo-5,5'-dichloro-2,2'-bipyrrole (DBP-Br4Cl2), 1,1'-dimethyl-3,3',4,4',5-pentabromo-5'-chloro-2,2'-bipyrrole (DBP-Br5Cl) and 1,1'-dimethyl-3,3',4,4',5,5'-hexabromo-2,2'-bipyrrole (DBP-Br6)--were quantitated and the extent of their magnification through an entire Arctic marine food web [measured as integrated trophic magnification factors (TMFs)] were calculated. The food web consisted of three zooplankton species (Calanus hyperboreus, Mysis oculata, and Sagitta sp.), one fish species [Arctic cod (Boreogadus saida)], four seabird species [dovekie (Alle alle), black guillemot (Cepphus grylle), black-legged kittiwake (Rissa tridactyla), and glaucous gull (Larus hyperboreus)], and one marine mammal species [ringed seal (Phoca hispida)]. Trophic levels in the food web were calculated from ratios of stable isotopes of nitrogen (15N/14N). All halogenated dimethyl bipyrrole (HDBP) congeners were found to significantly (Ptrophic level in the invertebrate--fish--seabird food web. DBP-Br4Cl2 (TMF= 14.6) was found to biomagnify to a greater extent than DBP-Br3Cl3 (TMF = 5.2), DBP-Br5Cl (TMF = 6.9), or DBP-Br6 (TMF = 7.0), even though the Kow of DBP-Br4CI2 was predicted to be lower than those of DBP-Br5Cl and DBP-Br6. None of the four HDBP congeners in ringed seals followed the general trend of increasing concentration with trophic level, which was possibly due to an ability of the seals to metabolize HDBPs. PMID:11808557

  7. Marine coastal sediments microbial hydrocarbon degradation processes: contribution of experimental ecology in the omics’era

    Directory of Open Access Journals (Sweden)

    Cristiana eCravo-Laureau

    2014-02-01

    Full Text Available Coastal marine sediments, where important biological processes take place, supply essential ecosystem services. By their location, such ecosystems are particularly exposed to human activities as evidenced by the recent Deepwater Horizon disaster. This catastrophe revealed the importance to better understand the microbial processes involved on hydrocarbon degradation in marine sediments raising strong interests of the scientific community. During the last decade, several studies have shown the key role played by microorganisms in determining the fate of hydrocarbons in oil-polluted sediments but only few have taken into consideration the whole sediment’s complexity. Marine coastal sediment ecosystems are characterized by remarkable heterogeneity, owning high biodiversity and are subjected to fluctuations in environmental conditions, especially to important oxygen oscillations due to tides. Thus, for understanding the fate of hydrocarbons in such environments, it is crucial to study microbial activities, taking into account sediment characteristics, physical-chemical factors (electron acceptors, temperature, nutrients, co-metabolites availability as well as sediment’s reworking due to bioturbation activities. Key information could be collected from in situ studies, which provide an overview of microbial processes, but it is difficult to integrate all parameters involved. Microcosm experiments allow to dissect in-depth some mechanisms involved in hydrocarbon degradation but exclude environmental complexity. To overcome these lacks, strategies have been developed, by creating experiments as close as possible to environmental conditions, for studying natural microbial communities subjected to oil pollution. We present here a review of these approaches, their results and limitation, as well as the promising future of applying ‘omics’ approaches to characterize in-depth microbial communities and metabolic networks involved in hydrocarbon

  8. Plio-Pleistocene imprint of natural climate cycles in marine sediments

    Energy Technology Data Exchange (ETDEWEB)

    Lebreiro, S. M.

    2013-06-01

    The response of Earth to natural climate cyclicity is written in marine sediments. The Earth is a complex system, as is climate change determined by various modes, frequency of cycles, forcings, boundary conditions, thresholds, and tipping elements. Oceans act as climate change buffers, and marine sediments provide archives of climate conditions in the Earths history. To read climate records they must be well-dated, well-calibrated and analysed at high-resolution. Reconstructions of past climates are based on climate variables such as atmospheric composition, temperature, salinity, ocean productivity and wind, the nature and quality which are of the utmost importance. Once the palaeoclimate and palaeoceanographic proxy-variables of past events are well documented, the best results of modelling and validation, and future predictions can be obtained from climate models. Neither the mechanisms for abrupt climate changes at orbital, millennial and multi-decadal time scales nor the origin, rhythms and stability of cyclicity are as yet fully understood. Possible sources of cyclicity are either natural in the form of internal ocean-atmosphere-land interactions or external radioactive forcing such as solar irradiance and volcanic activity, or else anthropogenic. Coupling with stochastic resonance is also very probable. I provide here, an overview of the cyclicity affecting the Earth on various time scales focussing upon the Plio-Pleistocene and Holocene epochs, together with a compilation of some of the key questions under debate, and a number of representative works that illustrate cyclicity in marine sediments. (Author)

  9. Linking microbial community structure to biogeochemical function in coastal marine sediments: Stable isotope probing combined with magnetic bead capture

    OpenAIRE

    Stal, L.J.; Boschker, H.T.S.; Miyatake, T.

    2011-01-01

    Microbial community structure and its biogeochemical functions in marine sediments can be successfully linked by using the improved Mag-SIP method in combination with other approaches. In this thesis, we were able to provide detailed information on the microorganisms responsible for the utilization of major substrates in marine sediments. It was shown that a number of important groups in the microbial community played a broader role than expected. Some surprising results are that oxygenic pho...

  10. Watershed-Marine Linkages: Monitoring how Terrigenous Runoff and Wave-Induced Resuspension Affect Marine Sediment Dynamics in Bays with Coral Reefs, St. John, USVI

    Science.gov (United States)

    Campbell, S.; Gray, S. C.; Whinney, J.; Ramos-Scharron, C. E.; Campbell, S.; LaFevor, M. C.

    2015-12-01

    In the USVI, land-based sedimentation in coastal marine environments has increased due to watershed development and is a major cause of coral reef degradation. Watershed runoff and wave/current-induced resuspension of benthic sediment contribute to turbidity/sedimentation. Our objectives are to characterize the spatial and temporal variability of marine sediment dynamics in response to runoff and resuspension in shoreline and reef areas of St. John, USVI, and directly compare the efficacy of time-integrated vs. high-resolution sediment monitoring approaches. To complement a six-year sediment trap study of sedimentation, nephelometers (10-min resolution) were deployed alongside sediment traps (26 day resolution) at four ephemeral stream outfalls and three reefs sites below comparable developed and minimally developed catchments. Watershed runoff was monitored using stream (10-min resolution) and peak crest (2-week resolution) gauges. Mean turbidity/deposition were 4/5 times greater at shore compared to reef sites, 5/6 times greater below developed compared to minimally developed catchments, 2/4 times greater during runoff compared to non-runoff periods, and 100/500 times background levels (time series median) following the largest runoff event of the 5-month time series. Turbidity values due to resuspension during non-runoff periods were primarily controlled by wave height (71% of the variability), tides, and the presence of finer sediment grains. However, the relative contribution to total sedimentation of resuspension vs. watershed runoff varied spatially between sites due to variations in bay geography, benthic sediment grain size, and catchment characteristics. Sediment traps and nephelometers recorded generally consistent temporal patterns of sedimentation at most sites. Though our study confirmed that watershed development increases turbidity and deposition in bays with coral reefs, multiple processes govern sediment dynamics and the distribution of sediments

  11. Distribution of molluscan remains in the sediment of the Chukchi Sea and its vicinity, the Arctic

    Institute of Scientific and Technical Information of China (English)

    Gao Aiguo; Xu Fengshan; Sun Haiqing; Li Lon

    2003-01-01

    The result of an analysis of mollusca remains collected from the Chukchi Sea, Beaufort Sea and Bering Sea in the First Chinese National Arctic Research Expedition, from July to September,1999 is presented. Seventeen species of mollusca have been identified, which belong to two classes: Bivalvia and Gastropoda. The compositions of the mollusca are very simple. According to the distribution pattern two groups may be distinguished among molluscan species. The Pan-Arctic and circumboreal group comprises Nuculana pernula, N. radiata, Nucula bellotii, Astarte montagui, Seripes groenlandicus, Macoma calcarea, M. moesta alaskana, Liocyma fluctuosa, Mya pseudoarenaria and Turritella polaris. Three species, Cyclocardia crebricos tata, Trichotrois coronata and Argobuccinum oregonense are components of the Pan-Arctic and Pacific boreal group. With regard to feeding habits, detritus feeders dominate. There are 7 species of detritus feeders, i.e. , Nuculana pernula, N. radiata,Nucula bellotii , Macoma calcarea , M. moesta alaskana , Macoma sp. and Trichotropis coronata . Detritus feeders are dominant with regard to the numbers of species as well as to the frequency of occurrence. Macoma calcarea is the most abundant species.

  12. The link between marine sediment records and changes in Holocene Saharan landscape: simulating the dust cycle

    Science.gov (United States)

    Egerer, Sabine; Claussen, Martin; Reick, Christian; Stanelle, Tanja

    2016-04-01

    Marine sediment records reveal an abrupt and strong increase in dust deposition in the North Atlantic at the end of the African Humid Period about 4.9 to 5.5 ka ago. The change in dust flux has been attributed to varying Saharan land surface cover. Alternatively, the enhanced dust accumulation is linked to enhanced surface winds and a consequent intensification of coastal upwelling. Here we demonstrate for the first time the direct link between dust accumulation in marine cores and changes in Saharan land surface. We simulate the mid-Holocene (6 ka BP) and pre-industrial (1850 AD) dust cycle as a function of Saharan land surface cover and atmosphere-ocean conditions using the coupled atmosphere-aerosol model ECHAM6.1-HAM2.1. Mid-Holocene surface characteristics, including vegetation cover and lake surface area, are derived from proxy data and simulations. In agreement with data from marine sediment cores, our simulations show that mid-Holocene dust deposition fluxes in the North Atlantic were two to three times lower compared with pre-industrial fluxes. We identify Saharan land surface characteristics to be the main control on dust transport from North Africa to the North Atlantic. We conclude that the increase in dust accumulation in marine cores is directly linked to a transition of the Saharan landscape during the Holocene and not due to changes in atmospheric or ocean conditions alone.

  13. (129)I record of nuclear activities in marine sediment core from Jiaozhou Bay in China.

    Science.gov (United States)

    Fan, Yukun; Hou, Xiaolin; Zhou, Weijian; Liu, Guangshan

    2016-04-01

    Iodine-129 has been used as a powerful tool for environmental tracing of human nuclear activities. In this work, a sediment core collected from Jiaozhou Bay, the east coast of China, in 2002 was analyzed for (129)I to investigate the influence of human nuclear activities in this region. Significantly enhanced (129)I level was observed in upper 70 cm of the sediment core, with peak values in the layer corresponding to 1957, 1964, 1974, 1986, and after 1990. The sources of (129)I and corresponding transport processes in this region are discussed, including nuclear weapons testing at the Pacific Proving Grounds, global fallout from a large numbers of nuclear weapon tests in 1963, the climax of Chinese nuclear weapons testing in the early 1970s, the Chernobyl accident in 1986, and long-distance dispersion of European reprocessing derived (129)I. The very well (129)I records of different human nuclear activities in the sediment core illustrate the potential application of (129)I in constraining ages and sedimentation rates of the recent sediment. The releases of (129)I from the European nuclear fuel reprocessing plants at La Hague (France) and Sellafield (UK) were found to dominate the inventory of (129)I in the Chinese sediments after 1990, not only the directly atmospheric releases of these reprocessing plants, but also re-emission of marine discharged (129)I of these reprocessing plants in the highly contaminated European seas. PMID:26821329

  14. Micromonospora fluostatini sp. nov., isolated from marine sediment.

    Science.gov (United States)

    Phongsopitanun, Wongsakorn; Kudo, Takuji; Mori, Mihoko; Shiomi, Kazuro; Pittayakhajonwut, Pattama; Suwanborirux, Khanit; Tanasupawat, Somboon

    2015-12-01

    The novel actinomycete strain PWB-003T, which produced fluostatins B and C antibiotics, was isolated from nearshore sediment collected from Panwa Cape, Phuket Province, Thailand. Data from the present polyphasic study indicated that strain PWB-003T represented a member of the genus Micromonospora. It produced single spores on substrate mycelia and contained meso-diaminopimelic acid in the cell-wall peptidoglycan. Whole-cell hydrolysate contained ribose, xylose, arabinose, mannose and glucose. The predominant menaquinone was MK-10 (H4). Cellular fatty acids comprised C18 : 1ω9c, iso-C16 : 0, anteiso-C17 : 0, iso-C15 : 0 and iso-C17 : 0. On the basis of 16S rRNA gene sequence similarity analysis, the novel strain was closely related to Micromonospora eburnea LK2-10T (99.38 %), Micromonospora chaiyaphumensis MC5-1T (99.16 %), Micromonospora yangpuensis FXJ6.011T (98.97 %), Micromonospora echinaurantiaca DSM 43904T (98.97 %), Micromonospora pallida DSM 43817T (98.97 %), Micromonospora sagamiensis DSM 43912T and Micromonospora auratinigra JCM 12357T (both 98.97 %). The G+C content of the DNA was 74.5 mol%. DNA-DNA relatedness values among strain PWB-003T and related type strains ranged from 11.3 ± 1.3 to 38.8 ± 1.1 %. On the basis of these observations, strain PWB-003T could be distinguished from its closely related type strains and is considered to represent a novel species of the genus Micromonospora, for which the name Micromonospora fluostatini sp. nov. (type strain PWB-003T = JCM 30529T = PCU 341T = TISTR 2345T) is proposed. PMID:26358439

  15. Kinetic parameters for nutrient enhanced crude oil biodegradation in intertidal marine sediments

    Directory of Open Access Journals (Sweden)

    Arvind K Singh

    2014-04-01

    Full Text Available Availability of inorganic nutrients, particularly N and P, is often a primary control on crude oil hydrocarbon degradation in marine systems. Nevertheless, there is a paucity of information on fundamental kinetic parameters for nutrient enhanced crude oil biodegradation that can be used to model the fate of crude oil in bioremediation programmes that use inorganic nutrient addition to stimulate oil biodegradation. Here we report fundamental kinetic parameters (Ks and qmax for nitrate- and phosphate-stimulated crude oil biodegradation under nutrient limited conditions and with respect to crude oil, under conditions where N&P are not limiting. Crude oil degradation was limited by both N&P availability. When N was added alone maximum rates of CO2 production measured were 3.94±0.46 µmol CO2 /g wet sediment/day. However when the same levels of N were added in the presence of 0.5% P w/w of oil (1.6 μmol P/g wet sediment maximum rates of measured CO2 production more than doubled (11.52±0.72 µmol CO2 /g wet sediment/day. Ks and qmax estimates for N (in the form of sodium nitrate when P was not limiting were 1.57±0.56 µmol/g wet sediment and 10.57±0.63 µmol CO2 /g wet sediment/day respectively. The corresponding values for P were 80 nmol/g wet sediment and 8.76±1.15 µmol CO2 /g wet sediment/day. The qmax values with respect to N and P were not significantly different (P< 0.05. Analysis of bacterial 16S rRNA genes indicated that Alcanivorax spp. were selected in these marine sediments with increasing inorganic nutrient concentration, whereas Cycloclasticus spp. were more prevalent at lower inorganic nutrient concentrations. These data suggest that simple empirical estimates of the proportion of nutrients added relative to crude oil concentrations may not be sufficient to guarantee successful crude oil bioremediation in oxic beach sediments. The data we present also help define the maximum rates and hence timescales required for bioremediation

  16. A 35,000 year record of terrigenous and marine lipids in Amazon Fan sediments

    Energy Technology Data Exchange (ETDEWEB)

    Boot, C.S.; Pancost, R.D. [Bristol Univ. (United Kingdom). Organic Geochemistry Unit; Ettwein, V.J.; Maslin, M.A. [University College London (United Kingdom). Environmental Change Research Centre; Weyhenmeyer, C.E. [Lawrence Livermore National Lab., CA (United States)

    2006-02-15

    Elemental and lipid analyses were carried out on sediments recovered from Ocean Drilling Program (ODP) Site 942 to provide a 35 kyr record of organic matter input to Amazon Fan sediments. Total organic carbon (TOC) and higher plant biomarker mass accumulation rates were an order of magnitude greater during the last glacial period compared to the current interglacial due to sea-level controlled variations in Amazon River sediment supply. Large maxima were also seen at {approx} 12 ka, which are most likely due to discharge events. Higher plant n-alkane average chain lengths did not change throughout the record, suggesting consistency in the source vegetation type. The abundance of taraxerol relative to other plant biomarkers increased at {approx} 12 ka, indicating increased mangrove input due to either higher mangrove productivity or increased erosion of mangrove deposits. The mass accumulation rates (MARs) of some bacterial and eustigmatophyte biomarkers varied closely with those of higher plant biomarkers and so seem to have a non-marine source. Long chain alkenones were present in some of the sediments, generally in very low concentration, indicating dilution of the marine signal with terrestrial organic matter. (author)

  17. Vertical activity distribution of dissimilatory nitrate reduction in coastal marine sediments

    DEFF Research Database (Denmark)

    Behrendt, A.; de Beer, D.; Stief, P.

    2013-01-01

    The relative importance of two dissimilatory nitrate reduction pathways, denitrification (DEN) and dissimilatory nitrate reduction to ammonium (DNRA), was investigated in intact sediment cores from five different coastal marine field sites (Dorum, Aarhus Bight, Mississippi Delta, Limfjord...... reduction was clearly dominated by DEN (59-131% of the total NO3- reduced) rather than by DNRA, irrespective of the sedimentary inventories of electron donors such as organic carbon, sulfide, and iron. Highest ammonium production via DNRA, accounting for up to 8.9% of the total NO3- reduced, was found...... at a site with very high concentrations of total sulfide and NH4+ within and below the layer in which NO3- reduction occurred. Sediment from two field sites, one with low and one with high DNRA activity in the core incubations, was also used for slurry incubations. Now, in both sediments high DNRA activity...

  18. Certification of Trace Elements and Methyl Mercury Mass Fractions in IAEA-456 Marine Sediment Samples

    International Nuclear Information System (INIS)

    The primary goal of the IAEA Environment Laboratories is to assist Member States in the use of both stable and radioisotope analytical techniques to understand, monitor and protect the environment. In this context, the major impact of large coastal cities on marine ecosystems is an issue of prime concern for the IAEA and the IAEA Environment Laboratories. The marine pollution assessments required to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. The IAEA Environment Laboratories has been assisting national laboratories and regional laboratory networks since the early 1970s through the provision of a reference material programme for the analysis of radionuclides, trace elements and organic compounds in marine samples. Quality assurance, quality control and associated good laboratory practice are essential components of all marine environmental monitoring studies. Quality control procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess t h e reliability and comparability of measurement data. Data that are not based on adequate quality assurance and quality control can be erroneous, and their misuse can lead to poor environmental management decisions. A marine sediment sample with certified mass amount contents for aluminium, arsenic, cadmium chromium, cobalt, copper, iron, lead, mercury, methyl mercury, manganese, nickel, vanadium and zinc was recently produced by the IAEA Environment Laboratories. This publication presents the sample preparation methodology, including material homogeneity and the stability study, the selection of laboratories, the evaluation of results from the certification campaign, and the assignment of property values and their associated uncertainty. As a result, certified values for mass fractions and associated expanded uncertainty were

  19. Certification of Trace Element Mass Fractions in IAEA-457 Marine Sediment Sample

    International Nuclear Information System (INIS)

    The primary goal of the IAEA Environment Laboratories in Monaco (NAEL) is to help Member States understand, monitor and protect the marine environment. The major impact exerted by large coastal cities on marine ecosystems is therefore of great concern to the IAEA and its Environment Laboratories. Given that marine pollution assessments of such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments, the NAEL has assisted national laboratories and regional laboratory networks through its Reference Products for Environment and Trade programme since the early 1970s. Quality assurance (QA), quality control (QC) and associated good laboratory practice are essential components of all marine environmental monitoring studies. QC procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess reliability and comparability of measurement data. QA can be realized by participation in externally organized laboratory performance studies, also known as interlaboratory comparisons, which compare and evaluate analytical performance and measurement capabilities of participating laboratories. Data that are not based on adequate QA/QC can be erroneous and their misuse can lead to incorrect environmental management decisions. A marine sediment sample with certified mass fractions for Ag, Al, As, Cd, Cr, Co, Cu, Fe, Hg, Li, Mn, Ni, Pb, Sn, Sr, V and Zn was recently produced by the NAEL in the frame of a project between the IAEA and the Korea Institute of Ocean Science and Technology. This report describes the sample preparation methodology, the material homogeneity and stability study, the selection of laboratories, the evaluation of results from the certification campaign and the assignment of property values and their associated uncertainty. As a result, reference values for mass fractions and associated expanded

  20. Phylogenetic Characterization of Marine Benthic Archaea in Organic-Poor Sediments of the Eastern Equatorial Pacific Ocean (ODP Site 1225).

    Science.gov (United States)

    Lauer, Antje; Sørensen, Ketil Bernt; Teske, Andreas

    2016-09-06

    Sequencing surveys of microbial communities in marine subsurface sediments have focused on organic-rich, continental margins; the database for organic-lean deep-sea sediments from mid-ocean regions is underdeveloped. The archaeal community in subsurface sediments of ODP Site 1225 in the eastern equatorial Pacific (3760 m water depth; 1.1 and 7.8 m sediment depth) was analyzed by PCR, cloning and sequencing, and by denaturant gradient gel electrophoresis (DGGE) of 16S rRNA genes. Three uncultured archaeal lineages with different depth distributions were found: Marine Group I (MG-I) within the Thaumarchaeota, its sister lineage Marine Benthic Group A (MBG-A), the phylum-level archaeal lineage Marine Benthic Group B (also known as Deep-Sea Archaeal Group or Lokiarchaeota), and the Deep-Sea Euryarchaeotal Group 3. The MG-I phylotypes included representatives of sediment clusters that are distinct from the pelagic members of this phylum. On the scale from fully oxidized, extremely organic carbon-depleted sediments (for example, those the South Pacific Gyre) to fully reduced, organic carbon-rich marine subsurface sediments (such as those of the Peru Margin), Ocean Drilling Program (ODP) Site 1225 falls into the non-extreme organic carbon-lean category, and harbors archaeal communities from both ends of the spectrum.

  1. Assessing regional populations of ground-nesting marine birds in the Canadian High Arctic

    Directory of Open Access Journals (Sweden)

    Mark Maftei

    2015-04-01

    Full Text Available The Queens Channel region of Nunavut is an ecologically distinct area within the Canadian High Arctic consisting of an extensive archipelago of small, low-lying gravel islands throughout which form several localized but highly productive polynyas. We used aerial survey and colony-monitoring data to assess regional- and colony-level fluctuations in the number of birds in this region between 2002 and 2013. Regional and colony-specific monitoring suggested that common eider (Somateria mollissima numbers are increasing, while numbers of Arctic terns (Sterna paradisaea may be in decline. Based on these data, we suggest that even infrequent comprehensive surveys are more useful than annual monitoring at specific sites in generating an accurate assessment of ground-nesting seabird populations at the regional level, and that dramatic fluctuations at individual colonies probably belie the overall stability of regional populations.

  2. Nitrogen isotopes in bulk marine sediment: linking seafloor observations with subseafloor records

    Directory of Open Access Journals (Sweden)

    J.-E. Tesdal

    2013-01-01

    Full Text Available The stable isotopes of nitrogen offer a unique perspective on changes in the nitrogen cycle, past and present. However, the presence of multiple forms of nitrogen in marine sediments can complicate the interpretation of bulk nitrogen isotope measurements. Although the large-scale global patterns of seafloor δ15N have been shown to match process-based expectations, small-scale heterogeneity on the seafloor, or alterations of isotopic signals during translation into the subseafloor record, could obscure the primary signals. Here, a public database of nitrogen isotope measurements is described, including both seafloor and subseafloor sediment samples ranging in age from modern to the Pliocene, and used to assess these uncertainties. In general, good agreement is observed between neighbouring seafloor sites within a 100 km radius, with 85% showing differences of < 1‰. There is also a good correlation between the δ15N of the shallowest (< 5 ka subseafloor sediments and neighbouring seafloor sites within a 100 km radius (R2 = 0.83, which suggests a reliable translation of sediments into the buried sediment record. Meanwhile, gradual δ15N decreases over multiple glacial–interglacial cycles appear to reflect post-depositional alteration in records from the deep sea (below 2000 m. We suggest a simple conceptual model to explain these 100-kyr-timescale changes in well-oxygenated, slowly accumulating sediments, which calls on differential loss rates for pools of organic N with different δ15N. We conclude that bulk sedimentary nitrogen isotope records are reliable monitors of past changes in the marine nitrogen cycle at most locations, and could be further improved with a better understanding of systematic post-depositional alteration. Furthermore, geochemical or environmental criteria should be developed in order to effectively identify problematic locations and to account for

  3. Assessment of radionuclides and heavy metals in marine sediments along the Upper Gulf of Thailand

    Science.gov (United States)

    Khuntong, S.; Phaophang, C.; Sudprasert, W.

    2015-05-01

    Due to the Fukushima Daiichi nuclear disaster in 2011 and the development of nuclear power plant in neighboring countries such as Vietnam in the near future, radionuclide assessment in marine sediment during 2010 - 2011 may be useful as background levels for radiation protection in Thailand. Marine sediments (10 samples) were collected approximately 1 km away from the coastline along Chonburi to Pattaya, Chonburi Province. The sediments were ground and sieved through 2-mm test sieve after air drying. Radionuclides were measured with a gamma spectrometer equipped with a well-calibrated HPGe detector. The samples were prepared in the same geometry as the reference material. The optimal counting time was 60,000 - 80,000 s for statistical evaluation and uncertainties. No contamination of 137Cs as an artificial radionuclide was found. Naturally-occurring radionuclides including 238U, 232Th and 40K were found. The mean specific activities of 238U, 232Th and 40K were 44 ± 10, 59 ± 17 and 463 ± 94 Bq/kg in the rainy season (2010); 41 ± 6, 50 ± 9 and 484 ± 83 Bq/kg in the winter (2010), and 39 ± 6, 41 ± 7 and 472 ± 81 Bq/kg in the summer (2011), respectively. The mean specific activities were higher than the values in the UNSCEAR report of 35, 30 and 400 Bq/kg for 238U, 232Th and 40K, respectively. From the measured specific activities, the absorbed dose rate, radium equivalent activity, external hazard index and annual external effective dose rate were calculated in order to assess the health risk. No radiation hazards related to the radioactivity in the sediment were expected. The accumulation of radionuclides varied with the particle size and the organic matter content in the sediment. The accumulation of heavy metals showed similar results to that of the radionuclides in the sediment.

  4. Causes for negative carbon isotope anomalies in Mesozoic marine sediments: Constraints from modern and ancient anoxic settings

    NARCIS (Netherlands)

    van Breugel, Y.

    2006-01-01

    Oceanic Anoxic Events (OAEs) were short periods in Earth history (˜0.5-1 Ma) characterized by atypically high burial rates of organic carbon in marine sediments worldwide. OAEs reflect increased marine primary production and/or enhanced organic matter preservation under anoxic water column condition

  5. Causes for negative carbon isotope anomalies in Mesozoic marine sediments : Constraints from modern and ancient anoxic settings

    NARCIS (Netherlands)

    Breugel, Y. van

    2006-01-01

    Oceanic Anoxic Events (OAEs) were short periods in Earth history (˜0.5-1 Ma) characterized by atypically high burial rates of organic carbon in marine sediments worldwide. OAEs reflect increased marine primary production and/or enhanced organic matter preservation under anoxic water column condition

  6. Viability of microcomputed tomography to study tropical marine worm galleries in humid muddy sediments

    Energy Technology Data Exchange (ETDEWEB)

    Pennafirme, Simone F., E-mail: sipennafirme@gmail.com [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Biologia. Dept. de Biologia Marinha; Machado, Alessandra S.; Lima, Inaya; Suzuki, Katia N.; Lopes, Ricardo T., E-mail: machado@lin.ufrj.br, E-mail: inaya@lin.ufrj.br, E-mail: norisuzuki6@yahoo.com.br, E-mail: ricardo@lin.ufj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), RJ (Brazil). Lab. de Instrumentacao Nuclear

    2013-07-01

    Bioturbation is an ecological process driven by organisms, which transports nutrients and gases from air/water to sediment through their galleries, by the time they feed, burrow and/or construct galleries. This exchange is vital to the maintenance of micro and macrobenthic organisms, mainly in muddy flat environments. Species with distinct galleries could create levels of bioturbation, affecting the benthic interactions. In this sense, it is fundamental developing a non-destructive method that permits identifying/quantifying the properties of these galleries. The recent advances in micro-computed tomography are allowing the high resolution 3D images generation. However, once muddy sediments are rich in organic matter and interstitial water, these would lead to motion artifacts which could, in turn, decrease the accuracy of galleries identification/quantification. In this context, the aim of this study was to develop a protocol which combines laboratory experiments and microtomography analysis in order to generate accurate 3D images of the small marine worm's galleries within humid muddy sediments. The sediment was collected at both muddy flats of Surui's and Itaipu lagoon's mangroves (RJ-Brazil), sieved (0.5mm mesh) and introduced with one individual of the marine worm Laeonereis acuta (Nereididae, Polychaeta) in each acrylic corer holders (4.4cm of internal diameter). High energy microtomography scanner was used to obtain 3D images and the setup calibration was 130 kV and 61 mA. Each acquisition image time was among 4h and 6h. Several procedures of drying remained water inside the cores were performed aiming obtaining images without movement artifacts due to circulating water, and this issue was one of the main studied parameter. In order to investigate possible chemical effects, 2ml of formalin (35%) with menthol were added to the surface of the cores. The results show that although the drying time was appropriated, the chemicals created bubbles

  7. Viability of microcomputed tomography to study tropical marine worm galleries in humid muddy sediments

    International Nuclear Information System (INIS)

    Bioturbation is an ecological process driven by organisms, which transports nutrients and gases from air/water to sediment through their galleries, by the time they feed, burrow and/or construct galleries. This exchange is vital to the maintenance of micro and macrobenthic organisms, mainly in muddy flat environments. Species with distinct galleries could create levels of bioturbation, affecting the benthic interactions. In this sense, it is fundamental developing a non-destructive method that permits identifying/quantifying the properties of these galleries. The recent advances in micro-computed tomography are allowing the high resolution 3D images generation. However, once muddy sediments are rich in organic matter and interstitial water, these would lead to motion artifacts which could, in turn, decrease the accuracy of galleries identification/quantification. In this context, the aim of this study was to develop a protocol which combines laboratory experiments and microtomography analysis in order to generate accurate 3D images of the small marine worm's galleries within humid muddy sediments. The sediment was collected at both muddy flats of Surui's and Itaipu lagoon's mangroves (RJ-Brazil), sieved (0.5mm mesh) and introduced with one individual of the marine worm Laeonereis acuta (Nereididae, Polychaeta) in each acrylic corer holders (4.4cm of internal diameter). High energy microtomography scanner was used to obtain 3D images and the setup calibration was 130 kV and 61 mA. Each acquisition image time was among 4h and 6h. Several procedures of drying remained water inside the cores were performed aiming obtaining images without movement artifacts due to circulating water, and this issue was one of the main studied parameter. In order to investigate possible chemical effects, 2ml of formalin (35%) with menthol were added to the surface of the cores. The results show that although the drying time was appropriated, the chemicals created bubbles within the

  8. Suspension freezing of bottom sediment and biota in the Northwest Passage and implications for Arctic Ocean sedimentation

    Science.gov (United States)

    Reimnitz, E.; Marincovich, L.; McCormick, M.; Briggs, W.M.

    1992-01-01

    No evidence was seen for entrainment by bottom adfreezing, bluff slumping, river flooding, dragging ice keels, or significant eolian transport from land to sea. Muddy sediment with pebbles and cobbles, algae with holdfasts, ostracodes with appendages, and well-preserved mollusks and sea urchins were collected from two sites in a 50 km long stretch of turbid ice. These materials indicate that suspension freezing reaching to a water depth of 25-30 m during the previous fall was responsible for entrainment. This mechanism requires rapid ice formation in open, shallow water during a freezing storm, when the ocean becomes supercooled, and frazil and anchor ice attach to and ultimately lift sediment and living organisms to the sea surface. -from Authors

  9. Fluid composition of the sediment-influenced Loki's Castle vent field at the ultra-slow spreading Arctic Mid-Ocean Ridge

    Science.gov (United States)

    Baumberger, Tamara; Früh-Green, Gretchen L.; Thorseth, Ingunn H.; Lilley, Marvin D.; Hamelin, Cédric; Bernasconi, Stefano M.; Okland, Ingeborg E.; Pedersen, Rolf B.

    2016-08-01

    The hydrothermal vent field Loki's Castle is located in the Mohns-Knipovich bend (73°N) of the ultraslow spreading Arctic Mid-Ocean Ridge (AMOR) close to the Bear Island sediment fan. The hydrothermal field is venting up to 320° C hot black smoker fluids near the summit of an axial volcanic ridge. Even though the active chimneys have grown on a basaltic ridge, geochemical fluid data show a strong sedimentary influence into the hydrothermal circulation at Loki's Castle. Compelling evidence for a sediment input is given by high alkalinity, high concentrations of NH4+, H2, CH4, C2+ hydrocarbons as well as low Mn and Fe contents. The low δ13C values of CO2 and CH4 and the thermogenic isotopic pattern of the C2+ hydrocarbons in the high-temperature vent fluids clearly point to thermal degradation of sedimentary organic matter and illustrate diminution of the natural carbon sequestration in sediments by hydrothermal circulation. Thus, carbon-release to the hydrosphere in Arctic regions is especially relevant in areas where the active Arctic Mid-Ocean Ridge system is in contact with the organic matter rich detrital sediment fans.

  10. Vitamin B1 in marine sediments: pore water concentration gradient drives benthic flux with potential biological implications

    OpenAIRE

    Monteverde, Danielle R.; Gómez-Consarnau, Laura; Cutter, Lynda; Chong, Lauren; Berelson, William; Sañudo-Wilhelmy, Sergio A.

    2015-01-01

    Vitamin B1, or thiamin, can limit primary productivity in marine environments, however the major marine environmental sources of this essential coenzyme remain largely unknown. Vitamin B1 can only be produced by organisms that possess its complete synthesis pathway, while other organisms meet their cellular B1 quota by scavenging the coenzyme from exogenous sources. Due to high bacterial cell density and diversity, marine sediments could represent some of the highest concentrations of putativ...

  11. Magnetostratigraphy of sediments from Lake El'gygytgyn ICDP Site 5011-1: paleomagnetic age constraints for the longest paleoclimate record from the continental Arctic

    Directory of Open Access Journals (Sweden)

    E. M. Haltia

    2013-09-01

    Full Text Available Paleomagnetic measurements were performed on sediments drilled from ICDP Site 5011-1 in Lake El'gygytgyn (67°30' N, 172°05' E located in Far East Russian Arctic. The lake fills partly a crater formed by a meteorite impact 3.58 ± 0.04 Ma ago. Sediments from three parallel cores (5011-1A, 5011-1B and 5011-1C, recovered from the middle part of the lake, yielded a total of 355 m of sediment. Sediments are characterized by variable lithology, where intervals of homogenous and laminated sediments alternate, and mass movement deposits of variable thickness occur frequently along the sediment profile. Mineral magnetic investigation made on sediments enclosed in core catchers suggests that magnetic carrier in these sediments is partly maghemitized Ti-rich pseudo-single domain magnetite. Its detrital origin could be shown by mineral magnetic measurements and SEM-EDS analyses performed on mini-sized cylindrical rock samples, polished rock sections, creek sediments and magnetic extracts prepared from them. The intensity of the natural remanent magnetization (NRM in the sediments is mainly high with a range from about 1 to 1000 mA m−1. Most of the sediments carry a stable magnetization component interpreted as primary depositional remanent magnetization. Characteristic inclination data show alternating intervals of steep positive and negative inclinations that were used to assign magnetic polarity to the lake sediment profile. This was a rather straightforward procedure owing to the mainly high quality of data. The Matuyama/Gauss (2.608 Ma and Brunhes/Matuyama (0.780 Ma reversals were recognized in the sediments. Furthermore, during the Gauss chron the Mammoth and Kaena reversed subchrons, and during the Matuyama, the Olduvai and Jaramillo normal subchrons, as well as the Réunion and Cobb Mountain cryptochrons were identified. Sediment deposition rate is highest at the base of the sequence laid down in the beginning of Gauss chron, when deposition rate

  12. Temperature response of denitrification and anaerobic ammonium oxidation rates and microbial community structure in Arctic fjord sediments.

    Science.gov (United States)

    Canion, Andy; Overholt, Will A; Kostka, Joel E; Huettel, Markus; Lavik, Gaute; Kuypers, Marcel M M

    2014-10-01

    The temperature dependency of denitrification and anaerobic ammonium oxidation (anammox) rates from Arctic fjord sediments was investigated in a temperature gradient block incubator for temperatures ranging from -1 to 40°C. Community structure in intact sediments and slurry incubations was determined using Illumina SSU rRNA gene sequencing. The optimal temperature (Topt ) for denitrification was 25-27°C, whereas anammox rates were optimal at 12-17°C. Both denitrification and anammox exhibited temperature responses consistent with a psychrophilic community, but anammox bacteria may be more specialized for psychrophilic activity. Long-term (1-2 months) warming experiments indicated that temperature increases of 5-10°C above in situ had little effect on the microbial community structure or the temperature response of denitrification and anammox. Increases of 25°C shifted denitrification temperature responses to mesophilic with concurrent community shifts, and anammox activity was eliminated above 25°C. Additions of low molecular weight organic substrates (acetate and lactate) caused increases in denitrification rates, corroborating the hypothesis that the supply of organic substrates is a more dominant control of respiration rates than low temperature. These results suggest that climate-related changes in sinking particulate flux will likely alter rates of N removal more rapidly than warming. PMID:25115991

  13. Interaction between Cenozoic fault activity and sediment influx in the Arctic region: new thermochronologic data and seismic study

    Science.gov (United States)

    Bigot-Buschendorf, Maelianna; Mouthereau, Frédéric; Fillon, Charlotte; Loget, Nicolas; Labrousse, Loïc; Werner, Philippe; Bernet, Matthias; Ehlers, Todd

    2015-04-01

    The Alaskan Brooks Range and its canadian counterpart, the British Mountains result from the Meso-Cenozoic collision of the Arctic continental margin with accreted volcanic arcs and adjacent continental terranes. Because of its location and known potential for oil industries, more attention has been brought to this area for the last few years. While the timing of collisional events, duration, and rates of exhumation associated with mountain building is now better understood, the causes of these exhumation events are still largely unknown. Published constraints and our present data are consistent with progressive cooling from 105 to 25 Ma, with rates of exhumation constant across the range until 35-25 Ma. From 35 Ma onwards, exhumation likely slowed in concomitance with underplating/duplexing in the inner part of the belt (Doonerak window) and activation of the northernmost thrust. The earliest cooling stage (from 100 Ma) marking the onset of the Brookian orogeny is recorded by a low order coarsening upward sequence in the foreland. On the contrary, the latest stage of cooling (at 35 Ma) is not linked to the construction of the range but more likely due to a reorganization of the wedge possibly related to changes in the regional climatic or geodynamic boundary conditions. First, we aim at reconstructing the time-temperature evolution of the British Mountains by combining new (U-Th)/He and fission-tracks ages on zircon and apatite ; our first thermochronological data in the British Mountains show ages ranging from 110 to 25 Ma from range to basin. These data will permit to reconstruct the thermal history of the British Mountains and its basin, and to estimate the exhumation rates associated to the main unities. Then, we also examine the role of climate during the Tertiary period. Some markers indicate a climate change at this period which could be registered in the sedimentation. Therefore we determine the part of climate by analyzing seismic lines in the Beaufort

  14. Microbial processes and organic priority substances in marine coastal sediments (Adriatic Sea, Italy)

    Science.gov (United States)

    Zoppini, Annamaria; Ademollo, Nicoletta; Amalfitano, Stefano; Dellisanti, Walter; Lungarini, Silvia; Miserocchi, Stefano; Patrolecco, Luisa; Langone, Leonardo

    2015-04-01

    PERSEUS EU FP7 Project aims to identify the interacting patterns of natural and human-derived pressures to assess their impact on marine ecosystems and, using the objectives and principles of the Marine Strategy Framework Directive (MSFD) as a vehicle, to design an effective and innovative research governance framework based on sound scientific knowledge. In the frame of this Project (subtask 1.3.3 ADREX: Adriatic and Ionian Seas Experiment), monitoring surveys were conducted in the Adriatic Sea (Italy) in order to study the variation of structural and functional characteristics of native bacterial communities and the occurrence of selected classes of organic priority substances in sediments. The study area represents a good natural laboratory sensitive to climate variability and human pressure, owing to the semi-enclosed nature of the Adriatic Sea and to the increasing trend of human activities in the coastal regions. During the cruise ADRI-13 (November 2013) and ADRI-14 (October 2014) we sampled several coastal sites from the mouth of the Po River to the Otranto strait. Surface sediments were collected in all areas, while sediment cores were sampled in selected sites. Microbes associated with marine sediments play an important role in the C-flux being responsible for the transformation of organic detritus (autochthonous and allochthonous) into biomass. The sediment bacterial abundance was determined by epifluorescence microscopy and the rate of bacterial carbon production by measuring the 3H-leucine uptake rates. The community respiration rate was estimated by the measurement of the electron transport system (ETS) activity. The sediment contamination level was determined by measuring the concentration of contaminants included in the list of organic priority substances: PAHs, bisphenol A (BPA), alkylphenols (APs). The extraction/clean-up of PAHs, BPA and APs was performed by ultrasonic bath with the appropriate solvents, followed by analytical determination with

  15. Impacts of Ocean Acidification on Sediment Processes in Shallow Waters of the Arctic Ocean

    OpenAIRE

    Frédéric Gazeau; Pieter van Rijswijk; Lara Pozzato; Middelburg, Jack J.

    2014-01-01

    Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster than those in sub-tropical regions. The present study investigates the effects of ocean acidification on sediment composition, processes and sedim...

  16. Calcareous microfossil-based orbital cyclostratigraphy in the Arctic Ocean

    Science.gov (United States)

    Marzen, Rachel E.; DeNinno, Lauren H.; Cronin, Thomas M.

    2016-10-01

    Microfaunal and geochemical proxies from marine sediment records from central Arctic Ocean (CAO) submarine ridges suggest a close relationship over the last 550 thousand years (kyr) between orbital-scale climatic oscillations, sea-ice cover, marine biological productivity and other parameters. Multiple paleoclimate proxies record glacial to interglacial cycles. To understand the climate-cryosphere-productivity relationship, we examined the cyclostratigraphy of calcareous microfossils and constructed a composite Arctic Paleoclimate Index (API) "stack" from benthic foraminiferal and ostracode density from 14 sediment cores. Following the hypothesis that API is driven mainly by changes in sea-ice related productivity, the API stack shows the Arctic experienced a series of highly productive interglacials and interstadials every ∼20 kyr. These periods signify minimal ice shelf and sea-ice cover and maximum marine productivity. Rapid transitions in productivity are seen during shifts from interglacial to glacial climate states. Discrepancies between the Arctic API curves and various global climatic, sea-level and ice-volume curves suggest abrupt growth and decay of Arctic ice shelves related to climatic and sea level oscillations.

  17. Recognizing magnetostratigraphy in overprinted and altered marine sediments: Challenges and solutions from IODP Site U1437

    Science.gov (United States)

    Musgrave, Robert J.; Kars, Myriam

    2016-08-01

    Core disturbance, drilling overprints, postdepositional acquisition of remanence, authigenic growth of magnetic iron sulfides, and alteration all contribute challenges to recognizing the primary magnetostratigraphy in marine sediments. We address these issues in a sequence of tuffaceous muds and volcaniclastics at International Ocean Discovery Program Site U1437 and produce the longest continuous magnetic polarity stratigraphy in the history of scientific ocean drilling. Remanence measurements were filtered to remove intervals affected by fluidization, plastic sediment disturbance, and core biscuiting. Drilling overprints are concentrated in the disturbed annulus surrounding intact core material. Bioturbation was limited to a vertical extent of at most 15 cm. Changes in sediment color, stiffness, and magnetic hysteresis all suggest that remanence was locked in within a few meters of the sediment-water interface. We did not observe any systematic offset between magnetostratigraphic and biostratigraphic datums. Authigenic growth of greigite, in response to both initial sulfate reduction in the upper 50 m of the sediment column and to deeper resupply of sulfate, has led to magnetic overprinting. Anomalous polarity artefacts, extending <5 m and occurring within about 20 m below a real polarity transition, appear to be due to a chemical remanence acquired by greigite produced during early diagenesis. Diagenetic magnetic mineral alteration resulted in the progressive loss of fine-grained magnetite, which enhanced susceptibility to drilling and postdrilling overprints and increased the resistance of these overprints to removal by conventional demagnetization. We recovered the magnetostratigraphic record from many samples with resistant overprints through low-temperature demagnetization through the Verwey transition.

  18. Bioremediation of oil polluted marine sediments: A bio-engineering treatment.

    Science.gov (United States)

    Cappello, Simone; Calogero, Rosario; Santisi, Santina; Genovese, Maria; Denaro, Renata; Genovese, Lucrezia; Giuliano, Laura; Mancini, Giuseppe; Yakimov, Michail M

    2015-06-01

    The fate of hydrocarbon pollutants and the development of oil-degrading indigenous marine bacteria in contaminated sediments are strongly influenced by abiotic factors such as temperature, low oxygen levels, and nutrient availability. In this work, the effects of different biodegradation processes (bioremediation) on oil-polluted anoxic sediments were analyzed. In particular, as a potential bioremediation strategy for polluted sediments, we applied a prototype of the "Modular Slurry System" (MSS), allowing containment of the sediments and their physical-chemical treatment (by air insufflations, temperature regulation, and the use of a slow-release fertilizer). Untreated polluted sediments served as the blank in a non-controlled experiment. During the experimental period (30 days), bacterial density and biochemical oxygen demand were measured and functional genes were identified by screening. Quantitative measurements of pollutants and an eco-toxicological analysis (mortality of Corophium orientale) were carried out at the beginning and end of the experiments. The results demonstrated the high biodegradative capability achieved with the proposed technology and its strong reduction of pollutant concentrations and thus toxicity. PMID:26496620

  19. Novel aromatic ring-hydroxylating dioxygenase genes from coastal marine sediments of Patagonia

    Directory of Open Access Journals (Sweden)

    Ferrero Marcela A

    2008-03-01

    Full Text Available Abstract Background Polycyclic aromatic hydrocarbons (PAHs, widespread pollutants in the marine environment, can produce adverse effects in marine organisms and can be transferred to humans through seafood. Our knowledge of PAH-degrading bacterial populations in the marine environment is still very limited, and mainly originates from studies of cultured bacteria. In this work, genes coding catabolic enzymes from PAH-biodegradation pathways were characterized in coastal sediments of Patagonia with different levels of PAH contamination. Results Genes encoding for the catalytic alpha subunit of aromatic ring-hydroxylating dioxygenases (ARHDs were amplified from intertidal sediment samples using two different primer sets. Products were cloned and screened by restriction fragment length polymorphism analysis. Clones representing each restriction pattern were selected in each library for sequencing. A total of 500 clones were screened in 9 gene libraries, and 193 clones were sequenced. Libraries contained one to five different ARHD gene types, and this number was correlated with the number of PAHs found in the samples above the quantification limit (r = 0.834, p nahAc-like genes, phnAc-like genes as identified in Alcaligenes faecalis AFK2, and phnA1-like genes from marine PAH-degraders from the genus Cycloclasticus. Conclusion These results show the presence of hitherto unidentified ARHD genes in this sub-Antarctic marine environment exposed to anthropogenic contamination. This information can be used to study the geographical distribution and ecological significance of bacterial populations carrying these genes, and to design molecular assays to monitor the progress and effectiveness of remediation technologies.

  20. Polychlorinated biphenyl (PCB) anaerobic degradation in marine sediments: microcosm study and role of autochthonous microbial communities.

    Science.gov (United States)

    Matturro, Bruna; Ubaldi, Carla; Grenni, Paola; Caracciolo, Anna Barra; Rossetti, Simona

    2016-07-01

    Polychlorobiphenyl (PCB) biodegradation was followed for 1 year in microcosms containing marine sediments collected from Mar Piccolo (Taranto, Italy) chronically contaminated by this class of hazardous compounds. The microcosms were performed under strictly anaerobic conditions with or without the addition of Dehalococcoides mccartyi, the main microorganism known to degrade PCBs through the anaerobic reductive dechlorination process. Thirty PCB congeners were monitored during the experiments revealing that the biodegradation occurred in all microcosms with a decrease in hepta-, hexa-, and penta-chlorobiphenyls (CBs) and a parallel increase in low chlorinated PCBs (tri-CBs and tetra-CBs). The concentrations of the most representative congeners detected in the original sediment, such as 245-245-CB and 2345-245-CB, and of the mixture 2356-34-CB+234-245-CB, decreased by 32.5, 23.8, and 46.7 %, respectively, after only 70 days of anaerobic incubation without any bioaugmentation treatment. Additionally, the structure and population dynamics of the microbial key players involved in the biodegradative process and of the entire mixed microbial community were accurately defined by Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) in both the original sediment and during the operation of the microcosm. The reductive dehalogenase genes of D. mccartyi, specifically involved in PCB dechlorination, were also quantified using real-time PCR (qPCR). Our results demonstrated that the autochthonous microbial community living in the marine sediment, including D. mccartyi (6.32E+06 16S rRNA gene copy numbers g(-1) sediment), was able to efficiently sustain the biodegradation of PCBs when controlled anaerobic conditions were imposed. PMID:26162439

  1. In situ lubricant degradation in Antarctic marine sediments. 1. Short-term changes.

    Science.gov (United States)

    Thompson, Belinda A W; Davies, Noel W; Goldsworthy, Paul M; Riddle, Martin J; Snape, Ian; Stark, Jonathan S

    2006-02-01

    A large-scale, in situ experiment was set up near the Bailey Peninsula area (Casey Station, East Antarctica) to monitor the natural attenuation of synthetic lubricants in marine sediments over five years. Here, we report the short-term changes after 5 and 56 weeks. The lubricants tested were an unused and used Mobil lubricant (0W/40; Exxon Mobil, Irving, TX, USA) and a biodegradable alternative (0W/20; Fuchs Lubricants, Harvey, IL, USA). Clean sediment was collected, contaminated with the lubricants, and deployed by divers onto the seabed in a randomized block design. The sampled sediments were analyzed by gas chromatography-flame-ionization detector and gas chromatography-mass spectrometry with selective ion monitoring. The base fluid of all lubricant treatments did not decrease significantly after 56 weeks in situ. Alkanoate esters of 1,1,1-tris(hydroxymethyl)propane in the biodegradable and unused lubricants were degraded extensively in situ; however, these esters constituted only a minor proportion of the lubricant volume. The additives, alkylated naphthalenes and substituted diphenylamines, were fairly resistant to degradation, which is of environmental concern because of their toxicity. The biodegradable lubricant did not break down to recognized biodegradable thresholds and, as such, should not be classified as biodegradable under Antarctic marine conditions. A separate experiment was conducted to determine the influence of sediment preparation and deployment on compound ratios within the lubricants, and we found that preparation and deployment of the contaminated sediments had only a minor effect on compound recovery. Further monitoring of this in situ experiment will provide much needed information about the long-term natural attenuation of lubricants. PMID:16519295

  2. Development of marine sediment bioassays and toxicity tests for monitoring and regulation in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Thain, J.; Matthiessen, P.

    1995-12-31

    There is a need in Europe and elsewhere for a broad suite of whole-sediment bioassays and toxicity tests which can be used for routine monitoring and assessment of the marine environment and for evaluating the toxic effects of chemicals which may find their way into sediments. Until recently, few European species had been incorporated into such tests but the availability of suitable methodologies is now increasing rapidly. Perhaps the most important recent activity in this area consisted of an international ring test of acute sediment toxicity test methods which was organized by the Oslo and Paris Commissions in 1993, using up to 4 offshore chemicals as test materials. It evaluated the performance of 4 acute (5--10 day) tests involving: the sea urchin Echinocardium cordatum, the bivalve mollusc Abra alba, the amphipod crustacean Corophium volutator, and the polychaete worm Arenicola marina. The ring test concluded that the C. volutator test was the most appropriate for evaluating offshore chemicals, but all these methods are now widely used in Europe, both as toxicity tests and as bioassays. For example, the A. marina procedure (which has both lethal and sublethal endpoints), in combination with the C. volutator method, is now routinely used in the UK for monitoring the toxicity of estuarine sediments. Further activities are in progress. Perhaps the most important is the development of chronic marine sediment tests and bioassays which can be used to assess the long-term effects of the many sedimentary contaminants which are able to persist in this type of habitat and possibly cause delayed effects on the growth and reproduction, etc. of benthic fauna.

  3. Triassic deep-marine sedimentation in the western Qinling and Songpan terrane

    Institute of Scientific and Technical Information of China (English)

    MENG; QingRen; QU; HongJie; HU; JianMin

    2007-01-01

    Triassic sequences in both the western Qinling and Songpan terrane are composed mostly of deep-marine sediments. A detailed study was carried out on main sedimentary facies of Triassic successions, showing that they resulted from diverse sedimentary processes, such as submarine debris-flows, turbidity currents, bottom-flows, suspension fallout, and fluidized sediment flows. Debris-flows are dividable into two types, gravelly and sandy debris-flows, respectively, and the sandy debris-flow deposits make up considerable portion of the Triassic successions concerned. Turbidite is characterized by occurrence of normal grading, and the whole Bouma sequences, though widely developed, are not totally attributed to true turbidity currents. The non-graded Ta division is thought to originate from sandy debris flows, whereas the rest divisions result from low-density currents or from bottom-current modification if they contain sedimentary structures related to traction currents. Four types of facies associations are distinguished within Triassic deep-marine successions: massive and thick-bedded coarse-grained facies association, medium- and thick-bedded sandstone with interlayered fine-grained facies association, interlayered thin-bedded fine-grained facies association, and syn-sedimentary slump/breccia facies association. Spatial distribution of the different facies associations suggests that Lower Triassic sedimentation occurred primarily in continental slope, submarine channels, and base-of-slope aprons in the Hezuo-Jianzha region of the western Qinling, whereas the Middle Triassic consists mainly of sedimentary facies of base-of-slope aprons and submarine incised valleys. The counterparts in the Dangchang-Diebu region, in contrast, are characterized by platform carbonates. The shallow-marine carbonates evolved into deep-marine facies since the Ladinian, indicative of rapid drowning of the Carnian carbonate platform in Middle Triassic times. Depositional history of Lower

  4. Zinc isotope ratios as indicators of diet and trophic level in Arctic marine mammals

    OpenAIRE

    Klervia Jaouen; Paul Szpak; Richards, Michael P.

    2016-01-01

    Carbon and nitrogen stable isotope ratios of bone collagen are an established method for dietary reconstruction, but this method is limited by the protein preservation. Zinc (Zn) is found in bioapatite and the isotopic compositions of this element constitute a very promising dietary indicator. The extent of fractionation of Zn isotopes in marine environments, however, remains unknown. We report here on the measurement of zinc, carbon and nitrogen isotopes in 47 marine mammals from the archaeo...

  5. Disentangling the fossil world from the deep biosphere in marine sediment

    Science.gov (United States)

    Kirkpatrick, J. B.; Walsh, E. A.; D'Hondt, S.

    2015-12-01

    DNA in marine sediment contains both detrital sequences and sequences from organisms native to the sediment. The demarcation between these two pools and their rates of respective turnover as sediment ages are generally unknown. Here we address these issues by quantifying the total extractable DNA pool and comparing it to the fraction of sequenced chloroplast DNA (cpDNA) in sediment from two sites in the Bering Sea. Sediment at both of these sites is initially oxic, but transitions to suboxic and anoxic within approximately hundred years. In our samples, cpDNA as a tracer of detrital DNA is dominated by identifiable phylotypes that match specific siliceous microfossil taxa. The fraction of sequences comprised by cpDNA decreases with increasing sediment age over hundreds of thousands of years (kyr) to 1.4 million years (Ma), but does not reach zero at either site. When we take into account the overall shrinkage of the DNA pool, this cpDNA fraction follows a power-law function, suggesting that the residual cpDNA becomes increasingly recalcitrant with age. This increasing recalcitrance can be explained by biological activity decreasing with sediment age and / or by preferential long-term survival of only the most thoroughly protected DNA. In either case, this trend suggests that DNA persisting beyond an initial period (ca. 100 - 200 kyr at our sites) has an increased chance of preservation at depth. The association of sequenced cpDNA reads with specific siliceous microfossil taxa suggests that microfossils may help to preserve DNA; DNA from such taxa may be useful for studies of paleoenvironmental conditions and biological evolution on timescales that approach or exceed one million years.

  6. Radionuclide impact on sediments and algae from Black sea marine ecosystems

    International Nuclear Information System (INIS)

    Radionuclide metals are the major part of anthropogenic fallout pollutants in the Black Sea marine ecosystems. The complex analysis of pollutant concentrations is a major concern for modern ecology in obtaining reliable information about the type and quantities of substances entering the marine environment. Marine macroalgae are important factor for nuclides accumulation in marine ecosystems. The ecological conditions at the Black Sea littoral zone vary depending on the location and depth. The seasonal change in macrophytic species is determined by the season, temperature and light regime. Some algae species are adaptive to contamination but some species react quickly to the environmental changes especially to the chemical contaminants. This paper deals with the problem of transboundary pollution in the Black Sea and the most significant pollution problem has been identified as the eutrophication phenomenon. Oxygen deficiency (hypoxia or anoxia) and mass mortality caused by eutrophication have become a permanent feature in the north-western shelf area where anoxic zones have expanded from covering 3500 km2 in 1973 to 40,000 km2 in 1990. The data for technogenic (mainly 137Cs) and natural radionuclides were determined in the sediment samples collected along the Bulgarian Black Sea coast. The measured levels correspond to those cited in the literature for background levels, showing no additional anthropogenic contamination. In sand and sandy sediments Cs content does not change greatly while the process of 137Cs accumulation is observed in slime and silt sediments. The data show that the 238U and 226Ra values are close at most of the locations. 226Ra /238U activity ratio (mean value) for sand and sandy sediments is in the range 0.55 - 0.85, meaning 226Ra deficit while the values for 226Ra /238U ratios in slime and silt sediments are close to the equilibrium. The obtained data show that radionuclide concentrations strongly depend on the sediment nature. Results for

  7. Building upon cooperative prospects amongst stakeholders for fighting Arctic marine invasion challenges

    DEFF Research Database (Denmark)

    Kourantidou, Melina; Kaiser, Brooks; Fernandez, Linda;

    expect that game theoretic environmental economic tools can help illuminate aspects of invasive species management significant for sound decision-making processes. Building blocks of such a game theoretic approach include the different players (stakeholders) involved. In our case study, we take...... into account the existing different management practices (for RKC) and the different market interests (based on consumer demand and fishing industry effort) as well as the ecosystem itself. At a minimum the following stakeholders have interdependent payoffs affecting not only the human actors but also...... in the decision making process to help articulate incentive-compatible ecosystem management strategies that are adaptive to new information garnered from sustained Arctic observations....

  8. Genotoxic and teratogenic potential of marine sediment extracts investigated with comet assay and zebrafish test

    International Nuclear Information System (INIS)

    Organic extracts of marine sediments from the North Sea and the Baltic Sea were investigated with two toxicity assays. The comet assay based on the fish cell line Epithelioma papulosum cyprini (EPC) was applied to determine the genotoxic potential; zebrafish embryos (Danio rerio) were used to quantify the teratogenic potential of the samples. EC50 values were calculated from dose-response curves for both test systems. Highest teratogenic and genotoxic effects normalised to total organic carbon (TOC) content were detected in sediment samples of different origins. Polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) are not likely to be the causes of the observed effects, as demonstrated by a two-step fractionation procedure of selected extracts. The toxic potential was more pronounced in fractions having polarity higher than those possessed by PAHs and PCBs. The suitability of the two in vitro test systems for assessing genotoxic and teratogenic effects of marine sediment extracts could be demonstrated. - Capsule: In vitro toxicity assays are used to assess genotoxic and teratogenic effects of environmental extracts

  9. Effect of salinity on methanogenic propionate degradation by acclimated marine sediment-derived culture.

    Science.gov (United States)

    Miura, Toyokazu; Kita, Akihisa; Okamura, Yoshiko; Aki, Tsunehiro; Matsumura, Yukihiko; Tajima, Takahisa; Kato, Junichi; Nakashimada, Yutaka

    2015-12-01

    Degradation of propionate under high salinity is needed for biomethane production from salt-containing feedstocks. In this study, marine sediment-derived culture was evaluated to determine the effect of salinity on methanogenic propionate degradation. Microbes in marine sediments were subjected to fed-batch cultivation on propionate for developing acclimatized cultures. The rate of propionate degradation increased eightfold during 10 rounds of cultivation. Microbial community composition was determined through pyrosequencing of 16S rRNA gene amplicons after 10 rounds of cultivation. Taxa analysis was conducted for the reads obtained by pyrosequencing. Known propionate degraders were undetectable in the acclimated culture. Comparison of bacterial taxa in the original sediment with those in the acclimated culture revealed that the populations of four bacterial taxa were significantly increased during acclimation. Methanolobus was the predominant archaea genus in the acclimated culture. The propionate degradation rate of the acclimated culture was not affected by salinity of up to equivalent of 1.9 % NaCl. The rate decreased at higher salinity levels and was more than 50 % of the maximum rate even at equivalent of 4.3 % NaCl. PMID:26364311

  10. Multi-elemental analysis of marine sediments of Manila Bay using x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    An analysis of the marine sediments of Manila Bay was done by employing X-ray fluorescence spectrometry. The general trends observed in sediments are increasing (Ca and Sr), decreasing (Zr), or constant (Cl, Na, S, K) with respect to depth, sometimes, no trend can be observed. These trends are further explained by correlations present among these elements, plus all the other elements. The two X RF data analysis methods Auto Quantify and AXIL were also compared on the basis of the correlation plot obtained. AutoQuantify gave clearer correlations; thus, results from this method were used for constructing correlation plots. Correlations using Microsoft Excel and Stat graphics Centurion X V show that there are naturally occurring [lithogenic (Si, Ti, Al, Mg, Rb, Zn and Fe), biogenic (Ca, Mg), and conservative (Na, Cl)] and non-naturally occurring [mostly anthropogenic, brought to the bodies of water by aeolian or fluvial input (heavy metals Pb-Cu-Zn and Ni-Cr)] correlation present in the sediments. Moreover, pairs of elements that may coexist in a source and not coexist in another (Cr and Mg, Cr and Ni) have also been observed. The heavy metal enrichment was attributed to the burning of fossil fuels, iron and steel manufacturing (present in Valenzuela-Bulacan area), ferry and fishing services and other industrialization activities present in Manila Bay. Marine organisms are affected by the presence of these heavy metals by means of bioaccumulations, and may later on affect humans because of trophic transfer and bio magnification. (author)

  11. Ecological and isotopic insights to the origin of archaeal tetraethers in marine sediments

    Science.gov (United States)

    Pearson, A.; Hurley, S. J.

    2012-12-01

    Thaumarchaeota, formerly known as Marine Group I Crenarchaeota, are believed to be the primary source of the isoprenoidal glycerol dialkyl glycerol tetraether lipids (GDGTs) found in the environment. Enrichment mesocosms and empirical correlations for marine sediments (TEX86) show a positive relationship between environmental temperature and the number of cyclopentyl or cyclohexyl rings contained within the GDGT structure. The TEX86 paleotemperature proxy has been applied across a large temporal range of geologic events and to sediments of widely varying depositional and diagenetic history. TEX86 assumes a direct correlation between the preserved GDGT ratios and SST. A number of fundamental assumptions underlie this correlation, including that: (1) GDGTs transported to the sediments reflect biomass of surface origin, (2) GDGTs produced by Archaea deeper in the water column should reflect deep temperatures and are not exported, and (3) community variations - including the potential contribution of GDGTs by Group II Euryarchaeota - do not appreciably affect the overall TEX86-SST relationship. Here we discuss evidence that questions all three of these assumptions and propose strategies for further understanding how GDGTs record paleoenvironments. These new approaches include greater application of physiological and culture studies; concurrent measurements of δ13C, Δ14C and D/H ratios of GDGTs; and cross-correlations with other paleotemperature proxies.

  12. Oxidation of pyrite and iron sulfide by manganese dioxide in marine sediments

    DEFF Research Database (Denmark)

    Schippers, A.; Jørgensen, BB

    2001-01-01

    Oxidation of pyrite (FeS2) under anaerobic conditions in marine sediments is experimentally shown for the first time. In slurry experiments with (FeS2)-Fe-55 and a MnO2 rich marine sediment an oxidation of (FeS2)-Fe-55 was detected which decreased with depth and decreasing concentration of MnO2...... in the sediment. FeS2 and iron sulfide (FeS) were oxidized chemically at pH 8 by MnO2 but not by nitrate or amorphic Fe(III) oxide. Elemental sulfur and sulfate were the only products of FeS oxidation, whereas FeS2 was oxidized to a variety of sulfur compounds, mainly sulfate plus intermediates...... such as thiosulfate, trithionate, tetrathionate. and pentathionate. Thiosulfate was oxidized by MnO2 to tetrathionate while other intermediates were oxidized to sulfate. The reaction products indicate that FeS2 was oxidized via the "Thiosulfatemechanism" and FeS via the "Polysulfide-mechanism" (Schippers and Sand...

  13. Biomonitoring polluted sediments in Arctic regions - possibilities and challenges using benthic foraminifera. Case studies from northern Norway

    Science.gov (United States)

    Skirbekk, Kari; Dijkstra, Noortje; Junttila, Juho; Sternal, Beata; Pedersen, Kristine Bondo; Forwick, Matthias; Carroll, JoLynn

    2016-04-01

    Biomonitoring pollution in marine environments using benthic foraminifera assemblages have proven to be a valid method for many regions. Two important reasons for their suitability are their sensitivity to changes in the environment and their rapid response time due to short life cycles. In addition, they are preserved in the sedimentary record, allowing for baseline studies of conditions prior to introduction of contaminants. Species of benthic foraminifera that appear to tolerate polluted sediments are referred to as opportunistic species. This notion is in general used for species able to dominate environments that are too stressful for most species. The high latitude setting of the northern Norwegian coastal zone experience high seasonality and, hence, largely changing conditions throughout a year: variations in water mass domination, freshwater influence, temperature and current velocity. It is possible that an environment like this is inhibited by a higher amount of opportunistic species generally thriving under high stress conditions. This might make the use of benthic foraminifera for biomonitoring more challenging, as the faunal compositions may be a result of a complex set of processes. Consequently, large datasets are necessary in order to make reliable conclusions, which in time may be used as generalized guidelines for biomonitoring in this geographical area. Here, we present preliminary results of benthic foraminiferal assemblages from two sites in Finnmark, northern Norway, which have been exposed to pollution. The main site is Repparfjorden, where the inner parts of the fjord were used as a submarine waste deposal site for mine tailings from a local copper mine during the 1970´s. Results from four marine sediment cores (10-20 cm long) containing sediments classified to be in moderate to very bad state (according to Norwegian sediment quality criteria) are presented. The contamination is seen in intervals of elevated copper content dated to the 1970

  14. Latitudinal variation in ecological opportunity and intraspecific competition indicates differences in niche variability and diet specialization of Arctic marine predators.

    Science.gov (United States)

    Yurkowski, David J; Ferguson, Steve; Choy, Emily S; Loseto, Lisa L; Brown, Tanya M; Muir, Derek C G; Semeniuk, Christina A D; Fisk, Aaron T

    2016-03-01

    Individual specialization (IS), where individuals within populations irrespective of age, sex, and body size are either specialized or generalized in terms of resource use, has implications on ecological niches and food web structure. Niche size and degree of IS of near-top trophic-level marine predators have been little studied in polar regions or with latitude. We quantified the large-scale latitudinal variation of population- and individual-level niche size and IS in ringed seals (Pusa hispida) and beluga whales (Delphinapterus leucas) using stable carbon and nitrogen isotope analysis on 379 paired ringed seal liver and muscle samples and 124 paired beluga skin and muscle samples from eight locations ranging from the low to high Arctic. We characterized both within- and between-individual variation in predator niche size at each location as well as accounting for spatial differences in the isotopic ranges of potential prey. Total isotopic niche width (TINW) for populations of ringed seals and beluga decreased with increasing latitude. Higher TINW values were associated with greater ecological opportunity (i.e., prey diversity) in the prey fish community which mainly consists of Capelin (Mallotus villosus) and Sand lance (Ammodytes sp.) at lower latitudes and Arctic cod (Boreogadus saida) at high latitudes. In beluga, their dietary consistency between tissues also known as the within-individual component (WIC) increased in a near 1:1 ratio with TINW (slope = 0.84), suggesting dietary generalization, whereas the slope (0.18) of WIC relative to TINW in ringed seals indicated a high degree of individual specialization in ringed seal populations with higher TINWs. Our findings highlight the differences in TINW and level of IS for ringed seals and beluga relative to latitude as a likely response to large-scale spatial variation in ecological opportunity, suggesting species-specific variation in dietary plasticity to spatial differences in prey resources and

  15. Thaumarchaeotal Signature Gene Distribution in Sediments of the Northern South China Sea: an Indicator of the Metabolic Intersection of the Marine Carbon, Nitrogen, and Phosphorus Cycles?

    OpenAIRE

    Dang, Hongyue; ZHOU, Haixia; Yang, Jinying; Ge, Huangmin; Jiao, Nianzhi; Luan, Xiwu; Zhang, Chuanlun; Martin G Klotz

    2013-01-01

    Thaumarchaeota are abundant and active in marine waters, where they contribute to aerobic ammonia oxidation and light-independent carbon fixation. The ecological function of thaumarchaeota in marine sediments, however, has rarely been investigated, even though marine sediments constitute the majority of the Earth's surface. Thaumarchaeota in the upper layer of sediments may contribute significantly to the reservoir of nitrogen oxides in ocean waters and thus to productivity, including the ass...

  16. Anoxic carbon degradation in Arctic sediments: Microbial transformations of complex substrates

    Science.gov (United States)

    Arnosti, C.; Finke, N.; Larsen, O.; Ghobrial, S.

    2005-05-01

    Complex substrates are degraded in anoxic sediments by the concerted activities of diverse microbial communities. To explore the effects of substrate complexity on carbon transformations in permanently cold anoxic sediments, four substrates— Spirulina cells, Isochrysis cells, and soluble high molecular weight carbohydrate-rich extracts of these cells (Spir-Ex and Iso-Ex)—were added to sediments collected from Svalbard. The sediments were homogenized, incubated anaerobically in gas-tight bags at 0°C, and enzyme activities, fermentation, and terminal respiration were monitored over a 1134 h time course. All substrate additions yielded a fraction (8%-13%) of carbon that was metabolized to CO 2 over the first 384 h of incubation. The timecourse of VFA (volatile fatty acid) production and consumption, as well as the suite of VFAs produced, was similar for all substrates. After this phase, pathways of carbon degradation diverged, with an additional 43%, 32%, 33%, and 8% of Isochrysis, Iso-Ex, Spirulina, and Spir-Ex carbon respired to CO 2 over the next 750 h of incubation. Somewhat surprisingly, the soluble, carbohydrate-rich extracts did not prove to be more labile substrates than the whole cells from which they were derived. Although Spirulina and Iso-Ex differed in physical and chemical characteristics (solid/soluble, C/N ratio, lipid and carbohydrate content), nearly identical quantities of carbon were respired to CO 2. In contrast, only 15% of Spir-Ex carbon was respired, despite the initial burst of activity that it fueled, its soluble nature, and its relatively high (50%) carbohydrate content. The microbial community in these cold anoxic sediments clearly has the capacity to react rapidly to carbon input; extent and timecourse of remineralization of added carbon is similar to observations made at much higher temperatures in temperate sediments. The extent of carbon remineralization from these specific substrates, however, would not likely have been predicted

  17. Anoxic carbon degradation in Arctic sediments: Microbial transformations of complex substrates

    DEFF Research Database (Denmark)

    Arnosti, Carol; Finke, Niko; Larsen, Ole;

    2005-01-01

    Complex substrates are degraded in anoxic sediments by the concerted activities of diverse microbial communities. To explore the effects of substrate complexity on carbon transformations in permanently cold anoxic sediments, four substrates—Spirulina cells, Isochrysis cells, and soluble high...... of carbon degradation diverged, with an additional 43%, 32%, 33%, and 8% of Isochrysis, Iso-Ex, Spirulina, and Spir-Ex carbon respired to CO2 over the next 750 h of incubation. Somewhat surprisingly, the soluble, carbohydrate-rich extracts did not prove to be more labile substrates than the whole cells from...

  18. Pan-Arctic concentrations of mercury and stable isotope ratios of carbon (δ(13)C) and nitrogen (δ(15)N) in marine zooplankton.

    Science.gov (United States)

    Pomerleau, Corinne; Stern, Gary A; Pućko, Monika; Foster, Karen L; Macdonald, Robie W; Fortier, Louis

    2016-05-01

    Zooplankton play a central role in marine food webs, dictating the quantity and quality of energy available to upper trophic levels. They act as "keystone" species in transfer of mercury (Hg) up through the marine food chain. Here, we present the first Pan-Arctic overview of total and monomethylmercury concentrations (THg and MMHg) and stable isotope ratios of carbon (δ(13)C) and nitrogen (δ(15)N) in selected zooplankton species by assembling data collected between 1998 and 2012 from six arctic regions (Laptev Sea, Chukchi Sea, southeastern Beaufort Sea, Canadian Arctic Archipelago, Hudson Bay and northern Baffin Bay). MMHg concentrations in Calanus spp., Themisto spp. and Paraeuchaeta spp. were found to increase with higher δ(15)N and lower δ(13)C. The southern Beaufort Sea exhibited both the highest THg and MMHg concentrations. Biomagnification of MMHg between Calanus spp. and two of its known predators, Themisto spp. and Paraeuchaeta spp., was greatest in the southern Beaufort Sea. Our results show large geographical variations in Hg concentrations and isotopic signatures for individual species related to regional ecosystem features, such as varying water masses and freshwater inputs, and highlight the increased exposure to Hg in the marine food chain of the southern Beaufort Sea. PMID:26874765

  19. Bioaccumulation and effect of sediment-associated silver in different forms in two marine deposit feeders

    DEFF Research Database (Denmark)

    Dai, Lina; Banta, Gary Thomas; Syberg, Kristian;

    2014-01-01

    to sediment amended with Ag in various forms (ionic Ag(I), nano-sized Ag and micron-sized Ag), and toxic endpoints were assessed at the whole organism level. After exposure for several weeks, no significant toxic effects were detected (i.e., mortality, growth rate and condition index) at the whole...... limited information at the whole organism level as to whether metallo-nanoparticles differ in toxicity from the same metals added to the environment in ionic or bulk form. In the present study, two organisms (i.e., a marine polychaete, Capitella teleta and a marine bivalve, Macoma balthica) were exposed...... organism level, although all forms of metallic Ag were accumulated in our test organisms. Our results thus did not confirm findings from studies performed at the subcellular level that have found the toxicity of Ag nanoparticles was more toxic than the corresponding metallic Ag in ionic and in bulk forms...

  20. Testaceans (Protozoa: Testacea) in Quaternary Permafrost Sediments of Bykovsky Peninsula, Arctic Yakutia

    OpenAIRE

    Bobrov, Anatoly A.; Siegert, Christine; Andreev, Andrei A.; Schirrmeister, Lutz

    2003-01-01

    The results of the first protozoological study in terms of paleoecology of long-term sediments and buried soils formed in the cryolite zone of northeastern Siberia are discussed. The data on testaceans (Protozoa: Testacea) inhabiting various sites of Bykovsky Peninsula, Laptev Sea coast near estuary of Lena, within the last 53 000 years (Late Pleistocene and Holocene) are presented.

  1. Impacts of Ocean Acidification on Sediment Processes in Shallow Waters of the Arctic Ocean

    NARCIS (Netherlands)

    Gazeau, F.; van Rijswijk, P.; Pozzato, L.; Middelburg, J.J.

    2014-01-01

    Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer wat

  2. Impacts of ocean acidification on sediment processes in shallow waters of the Arctic Ocean

    NARCIS (Netherlands)

    Gazeau, F.; van Rijswijk, P.; Pozzato, L.; Middelburg, J.J.

    2014-01-01

    Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer wat

  3. Seismic stratigraphy and sediment thickness of the Nansen Basin, Arctic Ocean

    Science.gov (United States)

    Engen, Øyvind; Gjengedal, Jakob Andreas; Faleide, Jan Inge; Kristoffersen, Yngve; Eldholm, Olav

    2009-03-01

    A Norwegian expedition to the western Nansen Basin, Yermak Plateau and the Hinlopen margin in 2001 acquired about 1100 km of 2-D multichannel seismic profiles and 50 wide-angle sonobuoy record sections. Analysis of these data establishes a regional seismic stratigraphic framework for the western Nansen Basin integrating previously published stratigraphic schemes. P-wave velocities and sediment thickness were derived within 7-8 per cent uncertainty from 2-D seismic ray tracing models of each sonobuoy section. Sediment thickness reaches 2 km in the studied area and increases towards the depocentre of the giant Franz-Victoria fan on the Barents-Kara continental margin. High-relief oceanic crystalline crust with 3.7 km s-1 average near-top velocity is infilled by four seismic sediment units with typical velocities 2.4, 2.2, 2.0 and 1.8 km s-1. A prominent regional seismic horizon between units 2 and 3 is tentatively correlated by basement onlap and sedimentation rates to a Miocene (~10 Ma) palaeoceanographic event, possibly the opening of the Fram Strait. The youngest unit is correlated to prograding sequences on the margin and to the onset of major slope failure caused by intensified glacio-fluvial drainage and ice sheet erosion during Northern Hemisphere glaciations (2.6-0.01 Ma).

  4. Diffuser Design for Marine Outfalls in Areas with Strong Currents, High waves and Sediment Transport

    DEFF Research Database (Denmark)

    Larsen, Torben

    1995-01-01

    The design of marine outfalls is often based on environmental criteria for a minimum initial dilution. Accordingly advanced diffuser arrangement are designed to fulfil these requirements. A large number of examples of malfunction and blocking in sea outfalls have occurred around the world...... as a result of this uncompromising consent to environmental demands. Two examples of unconventional design are given in this paper. Both cases involved risk of blockage of the diffuser section because of wave and current induced sediment transport The paper also discusses how acceptable far field dilution...

  5. Diffuser Design For Marine Outfalls in Areas With Strong Currents, High Waves and Sediment Transport

    DEFF Research Database (Denmark)

    Larsen, Torben

    1995-01-01

    The design of marine outfalls are often based on environmental criteria for a minimum initial dilution. Accordingly diffuser arrangement are designed to fulfil these requirements. A large number of examples of malfunction and blocking in sea outfalls have occurred around the world as a result...... of this uncompromising accept of environmental demands. Two examples of unconventional design are given in the paper. Both cases involved risk of blockage of the diffuser section because of wave and current induced sediment transport. The paper also discusses how acceptable far field dilution conditions can be achieved...

  6. Focus on sulfur count rates along marine sediment cores acquired by XRF Core Scanner

    OpenAIRE

    Chéron, Sandrine; Etoubleau, Joel; Bayon, Germain; Garziglia, Sebastien; Boissier, Audrey

    2016-01-01

    The aim of this study is to investigate the information provided by sulfur count rates obtained by X-ray fluorescence core scanner (XRF-CS) along sedimentary records. The analysis of two marine sediment cores from the Niger Delta margin shows that XRF-CS sulfur count rates obtained at the surface of split core sections with XRF-CS correlate with both direct quantitative pyrite concentrations, as inferred from X-ray powder diffraction (XRD) and sulfur determination by wavelength dispersive X-r...

  7. Decomposition of algal lipids in clay-enriched marine sediment under oxic and anoxic conditions

    Institute of Scientific and Technical Information of China (English)

    吕冬伟; 宋茜; 王旭晨

    2010-01-01

    A series of laboratory incubation experiments were conducted to examine the decomposition of algal organic matter in clay-enriched marine sediment under oxic and anoxic conditions.During the 245-day incubation period,changes in the concentrations of TOC,major algal fatty acid components (14:0,16:0,16:1,18:1 and 20:5),and n-alkanes (C16-C23) were quantified in the samples.Our results indicate that the organic matters were degraded more rapidly in oxic than anoxic conditions.Adsorption of fatty acids onto cla...

  8. Methane-generated( ) pockmarks on young, thickly sedimented oceanic crust in the Arctic. Vestnesa ridge, Fram strait

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, P.R.; Crane, K. (Naval Research Lab., Washington, DC (United States)); Sundvor, E. (Univ. of Bergen (Norway)); Max, M.D. (Supreme Allied Command Atlantic Undersea Research Centre, New York, NY (United States)); Pfirman, S.L. (Lamont Doherty Earth Observatory, Palisades, NY (United States))

    1994-03-01

    Acoustic backscatter imagery in the Farm strait (between Greenland and Spitzbergen) reveals a 1-3-km-wide, 50-km-long belt of -50 pointlike backscatter objects decorating the -1300-m-deep crest of Vestnesa Ridge, a 1 [minus]> 2 km thick sediment drift possibly underlain by a transform-parallel oceanic basement ridge (crustal ages approximately 3-14 Ma). A 3.5 kHz seismic-reflection profile indicates that at least some objects are pockmarks approximately 100-200 m in diameter and 10-20 m deep. The pockmarks (possibly also mud dipairs) may have been formed by evolution of methane generated by the decomposition of marine organic matter in the Vestnesa ridge sediment drift. The ridge may be underlain by an anticlinical carapace of methane-hydrate calculated to be 200-300 m thick, comparable to the hydrate thickness measured just to the south. The rising methane would collect in the ridge-crest trap, intermittently escaping to the sea floor. This hypothesis is supported by multichannel evidence for bright spots and bottom-simulating reflectors in the area. The pockmark belt may also be located above a transcurrent fault. Sediment slumps on the flanks of Vestnesa ridge and northeast of Molloy ridge may have been triggered by plate-boundary earthquakes and facilitated by methane hydrates. 11 refs., 4 figs.

  9. Numerical simulation of sealing effect of gas hydrate for CO2 leakage in marine sediment

    Science.gov (United States)

    Sato, T.; Yu, T.; Oyama, H.; Yoshida, T.; Nakashima, T.; Kamada, K.

    2015-12-01

    Although carbon dioxide capture and storage in subsea geological structure is regarded as one of the promising mitigation technologies against the global warming, there is a risk of CO2 leakage and it is required to develop numerical models to predict how the CO2 migrate in the marine sediments. It is said that there are CO2-trap mechanisms in the geological formations, such as capillary trap, dissolution trap, and mineral trap. In this study, we focus on another trap mechanism: namely, hydrate trap. If the water is deep in the ocean, say more than 250 m, CO2 hydrate forms near the sea floor, at which temperature and pressure conditions can stabilise CO2 hydrate. To predict the gas productivity, it is important to know permeability damage in hydrate bearing sediments. Although hydrate saturation is the same, the permeability is different depending on its spatial distribution within the pore of sand sediment. Here, to know where hydrate is formed in the pore of porous media, we propose a numerical model for estimating the microscopic distribution of CO2 hydrate in sand sediment using a classical nucleation theory and the phase-field model.

  10. Characterization of trace organic contaminants in marine sediment from Yeongil Bay, Korea: 1. Instrumental analyses

    International Nuclear Information System (INIS)

    Concentrations of polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides (HCB, HCHs, CHLs, and DDTs), polycyclic aromatic hydrocarbons (PAHs), alkylphenols (APs), and bisphenol A (BPA) were measured in 26 marine sediments collected from Yeongil Bay, Korea, in order to characterize their spatial distribution and sources. PCBs (2.85-26.5 ng/g, dry wt.) were detected mainly in the inner bay locations Mean OC pesticide ranged from 1.16 ng/g dry wt. for HCH to 0.05 ng/g dry wt. for HCB). PAH concentrations ranged from <10.0 to 1870 (mean: 309) ng/g dry wt., and were predominated 3- and 4-ring congeners. Concentrations of APs, such as nonylphenol, octylphenol, butylphenol (means 89.1, 4.61, 11.0 ng/g dry wt., respectively), were greater at locations proximal to municipal wastewater discharges. Concentrations of PCBs and PAHs were great near shipyards and industrial complexes. Vertical profiles of PAHs and APs indicated that they have been associated with sediments since the 1950s. - Among various sediment contaminant classes measured, nonylphenol and PAHs are responsible for the variability among sampling sites, suggesting the existence of multiple sources in Yeongil Bay sediment

  11. Ligand-enhanced electrokinetic remediation of metal-contaminated marine sediments with high acid buffering capacity.

    Science.gov (United States)

    Masi, Matteo; Iannelli, Renato; Losito, Gabriella

    2016-06-01

    The suitability of electrokinetic remediation for removing heavy metals from dredged marine sediments with high acid buffering capacity was investigated. Laboratory-scale electrokinetic remediation experiments were carried out by applying two different voltage gradients to the sediment (0.5 and 0.8 V/cm) while circulating water or two different chelating agents at the electrode compartments. Tap water, 0.1 M citric acid and 0.1 M ethylenediaminetetraacetic acid (EDTA) solutions were used respectively. The investigated metals were Zn, Pb, V, Ni and Cu. In the unenhanced experiment, the acid front could not propagate due to the high acid buffering capacity of the sediments; the production of OH(-) ions at the cathode resulted in a high-pH environment causing the precipitation of CaCO3 and metal hydroxides. The use of citric acid prevented the formation of precipitates, but solubilisation and mobilisation of metal species were not sufficiently achieved. Metal removal was relevant when EDTA was used as the conditioning agent, and the electric potential was raised up to 0.8 V/cm. EDTA led to the formation of negatively charged complexes with metals which migrated towards the anode compartment by electromigration. This result shows that metal removal from sediments with high acid buffering capacity may be achieved by enhancing the electrokinetic process by EDTA addition when the acidification of the medium is not economically and/or environmentally sustainable. PMID:26490900

  12. Simulating the modern δ30Si distribution in the oceans and in marine sediments

    Science.gov (United States)

    Gao, S.; Wolf-Gladrow, D. A.; Völker, C.

    2016-02-01

    The δ30Si of biogenic silica (δ30SiBSi) in marine sediments is a promising proxy for the reconstruction of silicic acid utilization by diatoms in the geological past. The application of this proxy, however, requires an understanding of the modern δ30Si distributions and their controlling mechanisms. Here we present results from a modern climate simulation with a coupled ocean-sediment model that includes a prognostic formulation of biogenic silica production with concurrent silicon isotopic fractionation. In agreement with previous studies, biological fractionation combined with physical transport and mixing determines the oceanic distribution of simulated δ30Si. A new finding is a distinct seasonal cycle of δ30Si in the surface ocean, which is inversely related to that of silicic acid concentration and mixed layer depth. We also provide the first simulation results of sedimentary δ30Si, which reveal that (1) the δ30SiBSi distribution in the surface sediment reflects the exported δ30SiBSi signal from the euphotic zone and (2) the dissolution of biogenic silica in the sediment acts as a source of relatively light δ30Si into the bottom waters of the polar oceans, while it is a source of heavier δ30Si to the subtropical South Atlantic and South Pacific.

  13. Correction of sound velocity depending on the temperature for unconsolidated marine sediment

    Science.gov (United States)

    Kim, Dae-Choul

    2016-04-01

    laboratory sound velocity measurements with systematic temperature change on unconsolidated marine sediment have been performed to establish the precise correction curves between temperature and the sound velocity. Piston and box core samples recovered from the East Sea and the South Sea of Korea were used for the measurement. The core samples were cooled (at temperature of nearly 0℃) and the temperature was gradually increased (from 0℃ to 30℃) to measure sound velocity depending on the changes in temperature. The sediment texture and physical properties (porosity, water content, and bulk density) were measured separately at the same depth. The rate of velocity increase for muddy, silty, and sandy sediment are about 2.63 m/s/℃, 2.74 m/s/℃, and 2.96 m/s/℃, respectively. This is similar to the velocity change rate, 2.97 m/s/℃ presented by Del Grosso (1952). The samples used in this research, however, have relatively higher porosity than those of Del Grosso (1952). Thus, the possibility of discrepancy is differences in water content which affect the sound velocity and measurement system. We used recently developed digital velocity measurement system using PXI based on LabVIEW. We suggest to employ this correction for the accurate in situ geoacoustic property from laboratory data particularly for the deep cold water sample such as the East Sea sediment that has very low bottom water temperature about 0℃. Keywords : in situ geoacoustic property, temperature correction, East Sea Acknowledgements: This research was supported by the Agency for Defense Development (UD14003DD) and by "Marine geological and geophysical mapping of the Korean seas" of the Korea Institute of Geoscience and Mineral Resources (KIGAM).

  14. Oil effect in freshly spiked marine sediment on Vibrio fischeri, Corophium volutator, and Echinocardium cordatum.

    Science.gov (United States)

    Brils, Jos M; Huwer, Sherri L; Kater, Belinda J; Schout, Peter G; Harmsen, Joop; Delvigne, Gerard A L; Scholten, Martin C Th

    2002-10-01

    The purpose of this study was to provide data to be used in The Netherlands for development of ecotoxicologically based quality criteria for oil-contaminated sediments and dredged material. In addition, the relation of toxicity to specific oil boiling-point fraction ranges was explored. Natural marine sediment, with a moisture, organic carbon, and silt content of approximately 80, 1.8, and 33% of the dry weight, respectively, was artificially spiked using a spiking method developed in this project. Aliquots of one part of the sediment were spiked to several concentrations of Gulf distillate marine grade A (DMA) gasoil (containing 64% C10-19) and aliquots of the other part to several concentrations of Gulf high viscosity grade 46 (HV46) hydraulic oil (containing 99.2% C19-40). Thus, for each individual oil type, a concentration series was created. Vibrio fischeri (endpoint: bioluminescence inhibition), Corophium volutator (endpoint:mortality), and Echinocardium cordatum (endpoint:mortality) were exposed to these spiked sediments for 10 min, 10 d and 14 d, respectively. Based on the test results, the effective concentration on 50% of the test animals was statistically estimated. For DMA gasoil and HV46 hydraulic oil, respectively, the effective concentrations were 43.7 and 2,682 mg/kg dry weight for V. fischeri, 100 and 9,138 mg/kg dry weight for C. volutator, 190, and 1064 mg/kg dry weight for E. cordatum. This study shows that the toxicity is strongly correlated with the lower boiling-point fractions and especially to those within the C10-C19 range. PMID:12371504

  15. Persistence of heavy metals in shallow arctic marine sediments contaminated by drilling effluents: Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Offshore oil exploration activity usually requires the discharge of drilling muds and formation cuttings into adjacent waters or on ice above these waters. Although...

  16. Response of fermentation and sulfate reduction to experimental temperature changes in temperate and Arctic marine sediments

    DEFF Research Database (Denmark)

    Finke, Niko; Jørgensen, Bo Barker

    2008-01-01

    Anaerobic degradation of organic material generally proceeds through a sequence of steps, including polymer hydrolysis, fermentation and respiration or methanogenesis. The intermediates, such as volatile fatty acids (VFA) or H(2), are generally maintained at low concentration, showing a close cou...

  17. Stable carbon isotope ratios of intact GDGTs indicate heterogeneous sources to marine sediments

    Science.gov (United States)

    Pearson, Ann; Hurley, Sarah J.; Walter, Sunita R. Shah; Kusch, Stephanie; Lichtin, Samantha; Zhang, Yi Ge

    2016-05-01

    Thaumarchaeota, the major sources of marine glycerol dibiphytanyl glycerol tetraether lipids (GDGTs), are believed to fix the majority of their carbon directly from dissolved inorganic carbon (DIC). The δ13C values of GDGTs (δ13CGDGT) may be powerful tools for reconstructing variations in the ocean carbon cycle, including paleoproductivity and water mass circulation, if they can be related to values of δ13CDIC. To date, isotope measurements primarily are made on the C40 biphytane skeletons of GDGTs, rather than on complete tetraether structures. This approach erases information revealed by the isotopic heterogeneity of GDGTs within a sample and may impart an isotopic fractionation associated with the ether cleavage. To circumvent these issues, we present δ13C values for GDGTs from twelve recent sediments representing ten continental margin locations. Samples are purified by orthogonal dimensions of HPLC, followed by measurement of δ13C values by Spooling Wire Microcombustion (SWiM)-isotope ratio mass spectrometry (IRMS) with 1σ precision and accuracy of ±0.25‰. Using this approach, we confirm that GDGTs, generally around -19‰, are isotopically "heavy" compared to other marine lipids. However, measured δ13CGDGT values are inconsistent with predicted values based on the 13C content of DIC in the overlying water column and the previously-published biosynthetic isotope fractionation for a pure culture of an autotrophic marine thaumarchaeon. In some sediments, the isotopic composition of individual GDGTs differs, indicating multiple source inputs. The data appear to confirm that crenarchaeol primarily is a biomarker for Thaumarchaeota, but its δ13C values still cannot be explained solely by autotrophic carbon fixation. Overall the complexity of the results suggests that both organic carbon assimilation (ca. 25% of total carbon) and multiple source(s) of exogenous GDGTs (contributing generally <30% of input to sediments) are necessary to explain the observed

  18. Optimizing sample pretreatment for compound-specific stable carbon isotopic analysis of amino sugars in marine sediment

    Directory of Open Access Journals (Sweden)

    R. Zhu

    2014-01-01

    Full Text Available Amino sugars are quantitatively significant constituents of soil and marine sediment, but their sources and turnover in environmental samples remain poorly understood. The stable carbon isotopic composition of amino sugars can provide information on the lifestyles of their source organisms and can be monitored during incubations with labeled substrates to estimate the turnover rates of microbial populations. However, until now, such investigation has been carried out only with soil samples, partly because of the much lower abundance of amino sugars in marine environments. We therefore optimized a procedure for compound-specific isotopic analysis of amino sugars in marine sediment employing gas chromatography-isotope ratio mass spectrometry. The whole procedure consisted of hydrolysis, neutralization, enrichment, and derivatization of amino sugars. Except for the derivatization step, the protocol introduced negligible isotopic fractionation, and the minimum requirement of amino sugar for isotopic analysis was 20 ng, i.e. equivalent to ~ 8 ng of amino sugar carbon. Our results obtained from δ13C analysis of amino sugars in selected marine sediment samples showed that muramic acid had isotopic imprints from indigenous bacterial activities, whereas glucosamine and galactosamine were mainly derived from organic detritus. The analysis of stable carbon isotopic compositions of amino sugars opens a promising window for the investigation of microbial metabolisms in marine sediments and the deep marine biosphere.

  19. Wintertime Arctic Ocean sea water properties and primary marine aerosol concentrations

    Directory of Open Access Journals (Sweden)

    J. Zábori

    2012-11-01

    Full Text Available Sea spray aerosols are an important part of the climate system through their direct and indirect effects. Due to the diminishing sea ice, the Arctic Ocean is one of the most rapidly changing sea spray aerosol source areas. However, the influence of these changes on primary particle production is not known.

    In laboratory experiments we examined the influence of Arctic Ocean water temperature, salinity, and oxygen saturation on primary particle concentration characteristics. Sea water temperature was identified as the most important of these parameters. A strong decrease in sea spray aerosol production with increasing water temperature was observed for water temperatures between −1°C and 9°C. Aerosol number concentrations decreased from at least 1400 cm−3 to 350 cm−3. In general, the aerosol number size distribution exhibited a robust shape with one mode close to dry diameter Dp 0.2 μm with approximately 45% of particles at smaller sizes. Changes in sea water temperature did not result in pronounced change of the shape of the aerosol size distribution, only in the magnitude of the concentrations. Our experiments indicate that changes in aerosol emissions are most likely linked to changes of the physical properties of sea water at low temperatures. The observed strong dependence of sea spray aerosol concentrations on sea water temperature, with a large fraction of the emitted particles in the typical cloud condensation nuclei size range, provide strong arguments for a more careful consideration of this effect in climate models.

  20. Plutonium behavior during the early diagenesis of marine sediments: applications to two marine environments labelled by radionuclides released from reprocessing plants

    International Nuclear Information System (INIS)

    The plutonium released into the English Channel and the Irish Sea by nuclear fuel reprocessing plants is mainly associated to sediments. Nevertheless, this association is partially reversible. This work combines a field study, carried out on the Cumbrian mud patch and the Esk estuary (Eastern Irish Sea), and laboratory experiments performed on carbonaceous coarse-grained sediments collected in the Central Channel. It presents new data on the plutonium solid partition in sediments and suggests realistic scenarios for describing its release from sediments to the water column. The role of reactive sulphides acting as temporary sink phases is shown in anoxic sediments; those sulphides are liable to release dissolved plutonium upon their oxidation. The plutonium is also bound to carbonates within the carbonaceous matrix and as carbonate surface complexes. Conceptual schemes of the behaviour of the plutonium in marine sediments are proposed; they highlight the strong remobilization potential of plutonium from marine sediments to the interstitial water. Its plutonium content can be injected into the overlying water column. (author)

  1. Late Miocene fossils from shallow marine sediments in Brunei Darussalam: systematics, palaeoenvironment and ecology.

    Science.gov (United States)

    Roslim, Amajida; Briguglio, Antonino; Kocsis, László; Ćorić, Stjepan; Razak, Hazirah

    2016-04-01

    The geology of Brunei Darussalam is fascinating but difficult to approach: rainforests and heavy precipitation tend to erode and smoothen the landscape limiting rocks exposure, whereas abundant constructions sites and active quarries allow the creation of short time available outcrop, which have to be immediately sampled. The stratigraphy of Brunei Darussalam comprises mainly Neogene sediments deposited in a wave to tide dominated shallow marine environment in a pure siliciclastic system. Thick and heavily bioturbated sandstone layers alternate to claystone beds which occasionally yield an extraordinary abundance and diversity of fossils. The sandstones, when not bioturbated, are commonly characterized by a large variety of sedimentary structures (e.g., ripple marks, planar laminations and cross beddings). In this study, we investigate the sediments and the fossil assemblages to record the palaeoenvironmental evolution of the shallow marine environment during the late Miocene, in terms of sea level change, chemostratigraphy and sedimentation rate. The study area is one of the best in terms of accessibility, extension, abundance and preservation of fossils; it is located in the region -'Bukit Ambug' (Ambug Hill), Tutong District. The fossils fauna collected encompasses mollusks, decapods, otoliths, shark and ray teeth, amber, foraminifera and coccolithophorids. In this investigation, sediment samples were taken along a section which measures 62.5 meters. A thick clay layer of 9 meters was sampled each 30 cm to investigate microfossils occurrences. Each sample was treated in peroxide and then sieved trough 63 μm, 150μm, 250μm, 450μm, 600μm, 1mm and 2mm sieves. Results point on the changes in biodiversity of foraminifera along the different horizons collected reflecting sea level changes and sediment production. The most abundant taxa identified are Pseoudorotalia schroeteriana, Ampistegina lessonii, Elphidium advenum, Quinqueloculina sp., Bolivina sp

  2. Iron Cycling in Marine Sediments - New Insights from Isotope Analysis on Sequentially Extracted Fe Fractions

    Science.gov (United States)

    Henkel, S.; Kasten, S.; Poulton, S.; Hartmann, J.; Staubwasser, M.

    2014-12-01

    Reactive Fe (oxyhydr)oxides preferentially undergo early diagenetic cycling and may cause a diffusive flux of dissolved Fe2+ from sediments towards the sediment-water interface. The partitioning of Fe in sediments has traditionally been studied by applying sequential extractions based on reductive dissolution of Fe minerals. We complemented the sequential leaching method by Poulton and Canfield [1] in order to be able to gain δ56Fe data for specific Fe fractions, as such data are potentially useful to study Fe cycling in marine environments. The specific mineral fractions are Fe-carbonates, ferrihydrite + lepidocrocite, goethite + hematite, and magnetite. Leaching was performed with acetic acid, hydroxylamine-HCl, Na-dithionite and oxalic acid. The processing of leachates for δ56Fe analysis involved boiling the samples in HCl/HNO3/H2O2, Fe precipitation and anion exchange column chromatography. The new method was applied to short sediment cores from the North Sea and a bay of King George Island (South Shetland Islands, Antarctica). Downcore mineral-specific variations in δ56Fe revealed differing contributions of Fe (oxyhydr)oxides to redox cycling. A slight decrease in easily reducible Fe oxides correlating with a slight increase in δ56Fe for this fraction with depth, which is in line with progessive dissimilatory iron reduction [2,3], is visible in the top 10 cm of the North Sea core, but not in the antarctic sediments. Less reactive (dithionite and oxalate leachable) fractions did not reveal isotopic trends. The acetic acid-soluble fraction displayed pronounced δ56Fe trends at both sites that cannot be explained by acid volatile sulfides that are also extracted by acetic acid [1]. We suggest that low δ56Fe values in this fraction relative to the pool of easily reducible Fe oxides result from adsorbed Fe(II) that was open to isotopic exchange with oxide surfaces, affirming the experimental results of Crosby el al. [2]. Hence, δ56Fe analyses on marine

  3. Biogeochemical Insights into B-Vitamins in the Coastal Marine Sediments of San Pedro Basin, CA

    Science.gov (United States)

    Monteverde, D.; Berelson, W.; Baronas, J. J.; Sanudo-Wilhelmy, S. A.

    2015-12-01

    Coastal marine sediments support a high abundance of mircoorganisms which play key roles in the cycling of nutrients, trace metals, and carbon, yet little is known about many of the cofactors essential for their growth, such as the B-vitamins. The suite of B-vitamins (B1, B2, B6, B7, B12) are essential across all domains of life for both primary and secondary metabolism. Therefore, studying sediment concentrations of B-vitamins can provide a biochemical link between microbial processes and sediment geochemistry. Here we present B-vitamin pore water concentrations from suboxic sediment cores collected in September 2014 from San Pedro Basin, a silled, low oxygen, ~900 m deep coastal basin in the California Borderlands. We compare the B-vitamin concentrations (measured via LCMS) to a set of geochemical profiles including dissolved Fe (65-160 μM), dissolved Mn (30-300 nM), TCO2, solid phase organic carbon, and δ13C. Our results show high concentrations (0.8-3nM) of biotin (B7), commonly used for CO2 fixation as a cofactor in carboxylase enzymes. Thiamin (B1) concentrations were elevated (20-700nM), consistent with previous pore water measurements showing sediments could be a source of B1 to the ocean. Cobalamin (B12), a cofactor required for methyl transfers in methanogens, was also detected in pore waters (~4-40pM). The flavins (riboflavin [B2] and flavin mononucleotide[FMN]), molecules utilized in external electron transfer, showed a distinct increase with depth (10-90nM). Interestingly, the flavin profiles showed an inverse trend to dissolved Fe (Fe decreases with depth) providing a potential link to culture experiments which have shown extracellular flavin release to be a common trait in some metal reducers. As some of the first B-vitamin measurements made in marine sediments, these results illustrate the complex interaction between the microbial community and surrounding geochemical environment and provide exciting avenues for future research.

  4. Lignin as an indicator of the sedimentation conditions on the Arctic shelf

    Science.gov (United States)

    Ulyantsev, A. S.; Romankevich, E. A.; Peresypkin, V. I.; Belyaev, N. A.; Semiletov, I. P.; Bratskaya, S. Yu.; Vetrov, A. A.; Sergienko, V. I.

    2016-03-01

    It is shown for the first time that the proportion of lignin in shelf deposits may range from 1/3 to the total concentration of organic carbon. The distribution of wood residues and lignin in the studied sedimentary formation is very uneven, which reflects the dynamic flux environment of sedimentation and OM supply. The calculated molecular indexes showed that most of the OM in deposits underwent insignificant diagenetic alterations.

  5. Certification of Trace Element Mass Fractions in IAEA-458 Marine Sediment Sample

    International Nuclear Information System (INIS)

    The primary goal of the IAEA Environment Laboratories (NAEL) is to help Member States understand, monitor and protect the marine environment. The major impact exerted by large coastal cities on marine ecosystems is therefore of great concern to the IAEA and its Environment Laboratories. Given that marine pollution assessments of such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments, the NAEL has assisted national laboratories and regional laboratory networks through its Reference Products for Environment and Trade programme since the early 1970s. Quality assurance (QA), quality control (QC) and associated good laboratory practice are essential components of all marine environmental monitoring studies. QC procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess reliability and comparability of measurement data. QA can be realized by participation in externally organized laboratory performance studies, also known as interlaboratory comparisons, which compare and evaluate the analytical performance and measurement capabilities of participating laboratories. Data that are not based on adequate QA/QC can be erroneous, and their misuse can lead to incorrect environmental management decisions. This report describes the sample preparation methodology, material homogeneity and stability study, selection of laboratories, evaluation of results from the certification campaign and assignment of property values and their associated uncertainty. As a result, reference values for mass fractions and associated expanded uncertainty for 16 trace elements (Al, As, Cd, Cr, Co, Cu, Fe, Hg, Li, Mn, Ni, Pb, Sr, Sn, V and Zn) in marine sediment were established

  6. Contamination of an arctic terrestrial food web with marine-derived persistent organic pollutants transported by breeding seabirds

    Energy Technology Data Exchange (ETDEWEB)

    Choy, Emily S., E-mail: echoy087@uottawa.c [Program for Chemical and Environmental Toxicology, Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5 (Canada); Kimpe, Linda E., E-mail: linda.kimpe@uottawa.c [Program for Chemical and Environmental Toxicology, Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5 (Canada); Mallory, Mark L., E-mail: mark.mallory@ec.gc.c [Canadian Wildlife Service, Environment Canada, Iqaluit, NU, X0A 0H0 (Canada); Smol, John P., E-mail: smolj@queensu.c [Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen' s University, Kingston, ON, K7L 3N6 (Canada); Blais, Jules M., E-mail: jules.blais@uottawa.c [Program for Chemical and Environmental Toxicology, Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5 (Canada)

    2010-11-15

    At Cape Vera, Devon Island (Nunavut, Canada), a colony of northern fulmars (Fulmarus glacialis) concentrates and releases contaminants through their guano to the environment. We determined whether persistent organic pollutants (POPs) from seabirds were transferred to coastal food webs. Snow buntings (Plectrophenax nivalis) were the most contaminated species, with {Sigma}PCB and {Sigma}DDT (mean: 168, 106 ng/g ww) concentrations surpassing environmental guidelines for protecting wildlife. When examined collectively, PCB congeners and DDT in jewel lichen (Xanthoria elegans) were lower in samples taken farther from the seabird colony, and increased with increasing {delta}{sup 15}N values. However, only concentrations of p'p-DDE:{Sigma}DDT and PCB-95 were significantly correlated inversely with distance from the seabird cliffs. Linkages between marine-derived POPs and their concentrations in terrestrial mammals were less clear. Our study provides novel contaminant data for these species and supports biovector transport as a source of organic contaminants to certain components of the terrestrial food web. - This study provides evidence of contaminant transport by seabirds to a coastal Arctic food web.

  7. Contamination of an arctic terrestrial food web with marine-derived persistent organic pollutants transported by breeding seabirds

    International Nuclear Information System (INIS)

    At Cape Vera, Devon Island (Nunavut, Canada), a colony of northern fulmars (Fulmarus glacialis) concentrates and releases contaminants through their guano to the environment. We determined whether persistent organic pollutants (POPs) from seabirds were transferred to coastal food webs. Snow buntings (Plectrophenax nivalis) were the most contaminated species, with ΣPCB and ΣDDT (mean: 168, 106 ng/g ww) concentrations surpassing environmental guidelines for protecting wildlife. When examined collectively, PCB congeners and DDT in jewel lichen (Xanthoria elegans) were lower in samples taken farther from the seabird colony, and increased with increasing δ15N values. However, only concentrations of p'p-DDE:ΣDDT and PCB-95 were significantly correlated inversely with distance from the seabird cliffs. Linkages between marine-derived POPs and their concentrations in terrestrial mammals were less clear. Our study provides novel contaminant data for these species and supports biovector transport as a source of organic contaminants to certain components of the terrestrial food web. - This study provides evidence of contaminant transport by seabirds to a coastal Arctic food web.

  8. Parasites as biological tags of marine, freshwater and anadromous fishes in North America from the Tropics to the Arctic.

    Science.gov (United States)

    Marcogliese, David J; Jacobson, Kym C

    2015-01-01

    Parasites have been considered as natural biological tags of marine fish populations in North America for almost 75 years. In the Northwest Atlantic, the most studied species include Atlantic cod (Gadus morhua), Atlantic herring (Clupea harengus) and the redfishes (Sebastes spp.). In the North Pacific, research has centred primarily on salmonids (Oncorhynchus spp.). However, parasites have been applied as tags for numerous other pelagic and demersal species on both the Atlantic and Pacific coasts. Relatively few studies have been undertaken in the Arctic, and these were designed to discriminate anadromous and resident salmonids (Salvelinus spp.). Although rarely applied in fresh waters, parasites have been used to delineate certain fish stocks within the Great Lakes-St Lawrence River basin. Anisakid nematodes and the copepod Sphyrion lumpi frequently prove useful indicators in the Northwest Atlantic, while myxozoan parasites prove very effective on the coast and open seas of the Pacific Ocean. Relative differences in the ability of parasites to discriminate between fish stocks on the Pacific and Atlantic coasts may be due to oceanographic and bathymetric differences between regions. Molecular techniques used to differentiate populations and species of parasites show promise in future applications in the field.

  9. Use of polyoxyethylene-6-lauryl ether and microwave-assisted extraction for the determination of chlorophenols in marine sediments

    Energy Technology Data Exchange (ETDEWEB)

    Santana, Cristina Mahugo; Ferrera, Zoraida Sosa; Rodriguez, Jose J. Santana

    2004-10-25

    Microwave-assisted micellar extraction was optimised and applied to the extraction, prior to analysis by liquid chromatography with diode array spectrophotometric detection, of chlorophenols in marine sediment samples. This study was carried out using a non-ionic surfactant polyoxyethylene-6-lauryl ether as extractant. Parameters studied included surfactant concentration, pH of the solution, extraction time and power. Once the method was optimised, it was applied to different spiked marine sediments from coasts of the Canary Islands (Spain). The results obtained indicate that irradiation of 500 W for 2 min achieved the best extraction efficiency (100% recovery) and standard deviation values <10%. Detection limits were obtained in the range 1.2-12.7 {mu}g g{sup -1} for the chlorophenols studied. The proposed method provides a simple, fast and organic solvent-free procedure to analyse for chlorophenols in marine sediment samples.

  10. Determination of naturally occurring uranium concentrations in seawater, sediment, and marine organisms in Japanese estuarine areas

    International Nuclear Information System (INIS)

    For safety assessments of geological repositories of nuclear waste, understanding of uranium (U) fate in estuarine areas is important because U chemical behavior in the areas is expected to be complex. Environmental transfer parameters such as sediment-water distribution coefficients (Kd) and concentration ratios (CRs) for marine organisms are useful in mathematical models for the assessment. However, due to its low concentration in estuarine water, Kd and CF data for U are scarce. Thus we studied a rapid method for separation and concentration of U from estuarine water samples using NOBIAS-CHELATE PA1 resin columns followed by inductively coupled plasma mass spectrometry (ICP-MS) for U measurement. Chemical recovery was about 100% at pH of 5.7 ± 0.1 from the water samples and alkali and alkaline earth metals were removed. The method was used to measure U concentrations in estuarine water samples collected at eight Japanese estuarine areas; they ranged from 0.1 to 3.8 μg L-1. We also measured U concentrations in sediment and marine organism samples by ICP-MS after acid digestion. Using these values, we observed K d (range: 39-284 L kg-1) and CRs (0.86-52 L kg-1 for macroalgae, 0.087-15 L kg-1 for crustaceans, and 0.52-93 L kg-1 for molluscs). (author)

  11. Anaerobic degradation of cyclohexane by sulfate-reducing bacteria from hydrocarbon-contaminated marine sediments

    Directory of Open Access Journals (Sweden)

    Ulrike eJaekel

    2015-02-01

    Full Text Available The fate of cyclohexane, often used as a model compound for the biodegradation of cyclic alkanes due to its abundance in crude oils, in anoxic marine sediments has been poorly investigated. In the present study, we obtained an enrichment culture of cyclohexane-degrading sulfate-reducing bacteria from hydrocarbon-contaminated intertidal marine sediments. Microscopic analyses showed an apparent dominance by oval cells of 1.5×0.8 m. Analysis of a 16S rRNA gene library, followed by whole-cell hybridization with group- and sequence-specific oligonucleotide probes showed that these cells belonged to a single phylotype, and were accounting for more than 80% of the total cell number. The dominant phylotype, affiliated with the Desulfosarcina-Desulfococcus cluster of the Deltaproteobacteria, is proposed to be responsible for the degradation of cyclohexane. Quantitative growth experiments showed that cyclohexane degradation was coupled with the stoichiometric reduction of sulfate to sulfide. Substrate response tests corroborated with hybridization with a sequence-specific oligonucleotide probe suggested that the dominant phylotype apparently was able to degrade other cyclic and n-alkanes, including the gaseous alkanes propane and n-butane. Based on GC-MS analyses of culture extracts cyclohexylsuccinate was identified as a metabolite, indicating an activation of cyclohexane by addition to fumarate. Other metabolites detected were 3-cyclohexylpropionate and cyclohexanecarboxylate providing evidence that the overall degradation pathway of cyclohexane under anoxic conditions is analogous to that of n-alkanes.

  12. Distribution of uranium in marine sediments; Distribucion de uranio en sedimentos marinos

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Ramirez T, J.J.; Lopez M, J.; Aspiazu, J. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico); Ruiz F, A.C. [U. Academica Mazatlan, ICML, UNAM (Mexico); Valero C, N. [CONALEP, 52000 Lerma, Estado de Mexico (Mexico)

    2008-07-01

    The marine sediments obtained by means of a sampling nucleus in the Gulf of Tehuantepec, Mexico, they have been object of crystallographic and morphological characterization. The PIXE analysis of some samples in study is shown. The normal methodology to carry out the alpha spectroscopy indicates that the sample should be dissolved, but due to the nature of the marine sediments, it thinks about the necessity to make a fractional separation of the sample components. In each stratum of the profile it separates the organic part and the mineral to recover the uranium. It was observed that in the organic phase, the uranium is in two oxidation states (IV and Vl), being necessary the radiochemical separation with a liquid/liquid column chromatographic that uses the di-2-ethyl hexyl phosphoric acid as stationary phase. The uranium compounds extracts are electrodeposited in fine layers on stainless steel disks to carry out the analysis by alpha spectroscopy. The spectroscopic analysis of the uranium indicates us that for each stratum one has a difference marked in the quotient of activities of {sup 234}U/{sup 238}U that depends on the nature of the studied fraction. These results give us a clear idea about how it is presented the effect of the uranium migration and other radioelements in the biosphere, with what we can determine which are the conditions in that these have their maximum mobility and to know their diffusion patterns in the different media studied. (Author)

  13. The Oil-Spill Snorkel: an innovative bioelectrochemical approach to accelerate hydrocarbons biodegradation in marine sediments

    Directory of Open Access Journals (Sweden)

    Carolina eCruz Viggi

    2015-09-01

    Full Text Available This study presents the proof-of-concept of the Oil-Spill Snorkel: a novel bioelectrochemical approach to stimulate the oxidative biodegradation of petroleum hydrocarbons in sediments. The Oil-Spill Snorkel consists of a single conductive material (the snorkel positioned suitably to create an electrochemical connection between the anoxic zone (the contaminated sediment and the oxic zone (the overlying O2-containing water. The segment of the electrode buried within the sediment plays a role of anode, accepting electrons deriving from the oxidation of contaminants. Electrons flow through the snorkel up to the part exposed to the aerobic environment (the cathode, where they reduce oxygen to form water. Here we report the results of lab-scale microcosms setup with marine sediments and spiked with crude oil. Microcosms containing 1 or 3 graphite snorkels and controls (snorkel-free and autoclaved were monitored for over 400 days. Collectively, the results of this study confirmed that the snorkels accelerate oxidative reactions taking place within the sediment, as documented by a significant 1.7-fold increase (p=0.023, two-tailed t-test in the cumulative oxygen uptake and 1.4-fold increase (p=0.040 in the cumulative CO2 evolution in the microcosms containing 3 snorkels compared to snorkel-free controls. Accordingly, the initial rate of total petroleum hydrocarbons (TPH degradation was also substantially enhanced. Indeed, while after 200 days of incubation a negligible degradation of TPH was noticed in snorkel-free controls, a significant reduction of 12±1% (p=0.004 and 21±1% (p=0.001 was observed in microcosms containing 1 and 3 snorkels, respectively. Although, the Oil-Spill Snorkel potentially represents a groundbreaking alternative to more expensive remediation options, further research efforts are needed to clarify factors and conditions affecting the snorkel-driven biodegradation processes and to identify suitable configurations for field

  14. The "Oil-Spill Snorkel": an innovative bioelectrochemical approach to accelerate hydrocarbons biodegradation in marine sediments.

    Science.gov (United States)

    Cruz Viggi, Carolina; Presta, Enrica; Bellagamba, Marco; Kaciulis, Saulius; Balijepalli, Santosh K; Zanaroli, Giulio; Petrangeli Papini, Marco; Rossetti, Simona; Aulenta, Federico

    2015-01-01

    This study presents the proof-of-concept of the "Oil-Spill Snorkel": a novel bioelectrochemical approach to stimulate the oxidative biodegradation of petroleum hydrocarbons in sediments. The "Oil-Spill Snorkel" consists of a single conductive material (the snorkel) positioned suitably to create an electrochemical connection between the anoxic zone (the contaminated sediment) and the oxic zone (the overlying O2-containing water). The segment of the electrode buried within the sediment plays a role of anode, accepting electrons deriving from the oxidation of contaminants. Electrons flow through the snorkel up to the part exposed to the aerobic environment (the cathode), where they reduce oxygen to form water. Here we report the results of lab-scale microcosms setup with marine sediments and spiked with crude oil. Microcosms containing one or three graphite snorkels and controls (snorkel-free and autoclaved) were monitored for over 400 days. Collectively, the results of this study confirmed that the snorkels accelerate oxidative reactions taking place within the sediment, as documented by a significant 1.7-fold increase (p = 0.023, two-tailed t-test) in the cumulative oxygen uptake and 1.4-fold increase (p = 0.040) in the cumulative CO2 evolution in the microcosms containing three snorkels compared to snorkel-free controls. Accordingly, the initial rate of total petroleum hydrocarbons (TPH) degradation was also substantially enhanced. Indeed, while after 200 days of incubation a negligible degradation of TPH was noticed in snorkel-free controls, a significant reduction of 12 ± 1% (p = 0.004) and 21 ± 1% (p = 0.001) was observed in microcosms containing one and three snorkels, respectively. Although, the "Oil-Spill Snorkel" potentially represents a groundbreaking alternative to more expensive remediation options, further research efforts are needed to clarify factors and conditions affecting the snorkel-driven biodegradation processes and to identify suitable

  15. The importance of sulphide binding for leaching of heavy metals from contaminated Norwegian marine sediments treated by stabilization/solidification.

    Science.gov (United States)

    Sparrevik, Magnus; Eek, Espen; Grini, Randi Skirstad

    2009-07-01

    Over time, Norwegian fjords and harbour areas have received contaminants from industrial activities and urban run-off, and measures to remediate contaminated marine sediments are therefore needed. Stabilization/solidification (S/S) technology, in which the contaminated marine sediments are mixed with cement and other binding agents, has been shown to be a promising remediation technology. This paper summarizes a study of the environmental effect of stabilization, highlighting the importance of sulphide binding governing the leaching of heavy metals from the S/S of contaminated marine sediments. The study is a part of a research project focusing on developing effective methods for S/S of contaminated seabed sediments for use in new construction areas. Four cementitious binders were tested on sediments from six different locations: Bergen, Gilhus, Grenland, Hammerfest, Sandvika and Trondheim. The sediments differed with respect to properties such as concentration of contaminants, water content, organic content and grain size distribution. Portland cement, Portland cement with fly ash, industry cement, and sulphate resistant cement, were tested as binders. The leaching from the S/S sediments after 28 days of curing was measured by using a standard leaching batch test (EN 12457-2: 2003), with seawater as leaching agent. The eluate was analysed for pH and redox, as well as content of heavy metals and organic contaminants. Available volatile sulphide (AVS) and simultaneously extractable metals (SEM) were also measured in the sediments. This paper focuses on the leaching of lead (Pb) and copper (Cu). A reduced leaching of Pb after stabilization was observed for the mixtures, whereas the leaching of Cu from Hammerfest sediments increased substantially after stabilization for all cementitious additions. Experiments show that Hammerfest samples had lower values of AVS than the other sediments. This was confirmed by the SEM/AVS analysis, highlighting the importance of

  16. Early Cretaceous marine sediments of the Lower Saxony Basin. The Gildehaus Sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Dellepiane, S.; Weiel, D. [Wintershall Holding GmbH, Barnstorf (Germany); Gerwert, D.; Mutterlose, J. [Bochum Univ. (Germany). Inst. fuer Geologie, Mineralogie und Geophysik

    2013-08-01

    During the Early Cretaceous (Berriasian - Aptian) the Lower Saxony Basin (LSB) formed the southernmost extension of the North Sea Basin. Sedimentation patterns of the LSB were controlled by divergent dextral shear movement causing differential subsidence related to early rifting in the North Sea. Up to 2000m of fine grained mudstones accumulated in the basin centre, while marginal marine, coarser grained siliciclastics were deposited along the western and southern margins of the LSB. The western marginal facies, outcropping along the Dutch-German border, is characterised by shallow marine sandstones of Valanginian - Hauterivian age. These units, which are separated by clay rich intervals, include the Bentheim Sdst., the Dichotomites Sdst., the Grenz Sdst., the Noricum Sdst. and the Gildehaus Sdst. These sandstones form a series of overall backstepping units, controlled by a main transgressive trend. Economically important are the Bentheim Sdst. and the Gildehaus Sdst., with a long oil producing history. The Bentheim Sdst. (early Valanginian) has been interpreted as an overall retrograding unit related to an incised valley infill with material mainly coming from the South. Tidal processes dominated the deposition of the Bentheim Sdst. The origin and genesis of the Gildehaus Sdst. (mid Hauterivian) is, however, less well understood. Here we present data from two wells drilled to the Gildehaus Sdst. (Emlichheim oil field) which provide evidence for a two fold subdivision of the unit. A well sorted massive quartz sandstone is followed by an interval composed of reworked coarse clastics of massflow origin. Micropalaeontological evidence suggests a fully marine, hemi-pelagic origin of the mud dominated matrix throughout the Gildehaus Sdst. These findings indicate a depositional environment quite different from that of the Bentheim Sdst. Short termed pulses of substantial input of clastic material from two different sources in the West to Southwest punctuated the overall

  17. Isoprenoid and branched GDGT-based proxies for surface sediments from marine, fjord and lake environments in Chile

    OpenAIRE

    J. Kaiser; Schouten, S.; Kilian, R.; H. W. Arz; F. Lamy; Sinninghe Damsté, J.S.

    2015-01-01

    Proxies based on glycerol dialkyl glycerol tetraether (GDGT) lipids from archaea [isoprenoid GDGTs] and bacteria [branched (br) GDGTs] in 33 surface sediments from marine, fjord and lake systems between 25°S and 50°S in Chile were analyzed. The regional TEXH86 calibration obtained from the marine and fjord sediments and mean annual surface temperature (T = 59.6 × TEXH86 + 33.0; r2 0.9; n = 23) is statistically identical to the global ocean calibration based on suspended particulate material i...

  18. Assessment of 210Po in agricultural soils and marine sediments of the Atlantic and Pacific oceans of Guatemala

    International Nuclear Information System (INIS)

    A radiochemical method consisting of 210Polonium extraction was made to measure radioactivity in samples of soil and marine sediments of Atlantic and Pacific Ocean. The solution of polonium it was treated to obtain the deposition of the metal over a zinc disc and was measured by alpha espectrometry system based on Planar Ion Planted Silice (PIPS) system. The concern about cultivated soils its consuption products from sea and soil come from these sources. The results shows that activity of 210Polonium in agricultural soils and marine sediments are below of ALI recommended by international standards

  19. Diversity and phylogeny of culturable spore-forming Bacilli isolated from marine sediments.

    Science.gov (United States)

    Ettoumi, Besma; Raddadi, Noura; Borin, Sara; Daffonchio, Daniele; Boudabous, Abdellatif; Cherif, Ameur

    2009-09-01

    Members of the genus Bacillus and related genera are ubiquitous in nature. However, Bacillus species isolated from marine sediments have attracted less interest respect to their terrestrial relatives. Here, we report the phylogenetic diversity of a collection of 96 Bacilli, isolated from 17 distinct stations of 5 oceanographic campaigns. The diversity was analysed by phenotypic and molecular approaches based on the amplified rDNA restriction analysis (ARDRA), amplification of the internal transcribed spacers (ITS-PCR) and on 16S rRNA sequencing. Intra-specific polymorphism was efficiently detected by biochemical analysis and ARDRA while results of ITS-PCR were in agreement with 16S rRNA sequencing. The identification results assigned 68% of the isolates to the species B. subtilis, B. licheniformis, B. pumilus and B. cereus. Phylogenetic analysis allowed the separation of 9 isolates in a clade that may represent a group of obligate marine Bacillus since they clustered with B. firmus, B. foraminis and marine isolates with metal oxidation and bioaccumulation capabilities. The remaining isolates showed a close affiliation to the genera Virgibacillus, Gracilibacillus and Paenibacillus. The widespread of Bacilli and their high diversity level observed in this work point out the need of more extensive studies to understand their distribution and ecology in deep-sea environments. PMID:19322832

  20. Possible origin of n -alkanes with a remarkable even-to-odd predominance in recent marine sediments

    Science.gov (United States)

    Nishimura, Mitsugu; Baker, Earl W.

    1986-02-01

    N- alkane distributions with a remarkable even-to-odd predominance (C 16-C 24) were found in marine surface sediments. The previously proposed diagenetic reduction of the corresponding n- fatty acids could not be considered as a source for these N- alkane. Based on a comparison of compositional features of n- alkane, n- fatty acid and n- alcohol distributions, carbon isotope analyses, and other geochemical parameters, the data indicate that the even-predominant n- alkanes were derived directly from marine bacteria.

  1. Radioactivity and metal concentrations in marine sediments associated with mining activities in Ierissos Gulf, North Aegean Sea, Greece.

    Science.gov (United States)

    Pappa, F K; Tsabaris, C; Ioannidou, A; Patiris, D L; Kaberi, H; Pashalidis, I; Eleftheriou, G; Androulakaki, E G; Vlastou, R

    2016-10-01

    Marine sediment samples were collected from Ierissos Gulf, N Aegean Sea, close to the coastal mining facilities. Measurements of radionuclide and metal concentrations, mineral composition and grain size distribution were performed. The concentrations of (226)Ra, (235)U and trace metals showed enhanced values in the port of Stratoni compared with those obtained near to Ierissos port. The dose rates received by marine biota were also calculated by the ERICA Assessment Tool and the results indicated no significant radiological risk. PMID:27474903

  2. Isolation and characterization of a marine bacterium producing protease from Chukchi Sea, Arctic

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A Gram negative bacterium Ar/W/b/75°25'N/1 producing extracellular alkaline protease was isolated from surface water of latitude 75°25'N, and longitude 162°25'W in Chukchi sea, Arctic. The strain can grow at the temperature range from 7℃ to 30℃, and grow better at 30(℃. It can not grow at 40℃. Keeping certain salinity concentration in medium is necessary for cell growth. It grows well in medium containing salinity concentration from 0. 5 % to 10 % sodium chloride. Glucose, sucrose and soluble starch can be utilized by the strain, among which glucose is the optimal carbon source. Peptone is the optimal organic nitrogen source for cell growth and protease producing, and ammonium nitrate is the optimal inorganic nitrogen source.About 75.7% of total protease of the strain are extracellular enzyme. Optimal temperature for proteolytic activity is at 40℃. Protease of the strain keeps stable below 40℃, and shows high proteolytic activity within the pH range from 7 to 11.

  3. Latitudinal trends in fluxes and congener patterns of PCBs inferred from lake sediment cores from mid-latitude and Arctic Lakes

    Energy Technology Data Exchange (ETDEWEB)

    Muir, D.; Omelchenko, A.; Grift, N.; Lockhart, L.; Wilkinson, P.; Brunskill, G. [Department of Fisheries and Oceans, Winnipeg, Manitoba (Canada). Freshwater Inst.; Robbins, J.A. [NOAA, Ann Arbor, MI (United States). Great Lakes Environmental Research Lab.

    1995-12-31

    Sediment cores collected from 9 remote lakes in central and Arctic Canada (49{degree}N to 82{degree}N and from 71{degree} to 136{degree}W) were analyzed for PCBs with the objective of examining latitudinal and temporal trends in deposition. Core slices (1--1.3 cm) were dated with {sup 210}Pb and {sup 137}Cs using the Robbins rapid steady-state mixing model and sediment focusing factors were determined with the aid of soil cores or predictions of historical radionuclide deposition. Slices were freeze-dried, Soxhlet extracted with DCM and chromatographed on Florisil, then analyzed by high resolution GC-ECD with confirmation by GC-HRMS. {Sigma}PCB concentrations in surface sediments were low ranging from 8 to 40 ng{center_dot}g{sup {minus}1} (dry wt) in southern mid-continental sites (49--63{degree}N) to 2 ng{center_dot}g{sup {minus}1} in Lake Hazen, the most northerly location (82{degree}N). Highest concentrations were found in the most recent slices (1980s) of cores from high Arctic lakes (at 75 and 82{degree}N) whereas peak concentrations were reached earlier (in the 1970s) at more southerly locations. Principal components analysis revealed that sediments from high Arctic lakes could be distinguished by greater proportions of lower chlorinated PCBs in comparison with published results for Lakes Ontario and Superior. Focus corrected {Sigma}PCBs fluxes ranged from 305 to 920 ng{center_dot}m{sup 2}{center_dot}yr{sup {minus}1} in the 9 lakes and were negatively correlated with latitude (r{sup 2} = 0.53). Fluxes of Cl{sup 8} CBs had a strong negative correlation with latitude (r2 = 0.88) while Cl{sup 3} CBs showed no latitudinal trend. The results generally support several of the predictions of the cold condensation hypothesis.

  4. Rare earth elements in core marine sediments of coastal East Malaysia by instrumental neutron activation analysis.

    Science.gov (United States)

    Ashraf, Ahmadreza; Saion, Elias; Gharibshahi, Elham; Kamari, Halimah Mohamed; Kong, Yap Chee; Hamzah, Mohd Suhaimi; Elias, Md Suhaimi

    2016-01-01

    A study was carried out on the concentration of REEs (Dy, Sm, Eu,Yb, Lu, La and Ce) that are present in the core marine sediments of East Malaysia from three locations at South China Sea and one location each at Sulu Sea and Sulawesi Sea. The sediment samples were collected at a depth of between 49 and 109 m, dried, and crushed to powdery form. The entire core sediments prepared for Instrumental Neutron Activation Analysis (INAA) were weighted approximately 0.0500 g to 0.1000 g for short irradiation and 0.1500 g to 0.2000 g for long irradiation. The samples were irradiated with a thermal neutron flux of 4.0×10(12) cm(-2) s(-1) in a TRIGA Mark II research reactor operated at 750 kW. Blank samples and standard reference materials SL-1 were also irradiated for calibration and quality control purposes. It was found that the concentration of REEs varies in the range from 0.11 to 36.84 mg/kg. The chondrite-normalized REEs for different stations suggest that all the REEs are from similar origins. There was no significant REEs contamination as the enrichment factors normalized for Fe fall in the range of 0.42-2.82. PMID:26405840

  5. Metagenomic analysis reveals potential biodegradation pathways of persistent pesticides in freshwater and marine sediments.

    Science.gov (United States)

    Fang, Hua; Cai, Lin; Yang, Ying; Ju, Feng; Li, Xiangdong; Yu, Yunlong; Zhang, Tong

    2014-02-01

    The abundance and diversity of biodegradation genes (BDGs) and potential degradation pathways of dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), and atrazine (ATZ) in freshwater and marine sediments were investigated by metagenomic analysis using 6 datasets (16Gb in total). The datasets were derived using Illumina high-throughput sequencing and were based on BLAST against self-established databases of BDGs, DDT degradation genes (DDGs), HCH degradation genes (HDGs), and ATZ degradation genes (ADGs). The results showed that the abundance and diversity of BDGs, DDGs, HDGs, and ADGs varied with sample source and locations. The lip and mnp genes, which encode for peroxidase, and the carA gene, which encodes for laccase, were detected as the dominant genes for degradation of organic pollutants. The hdt, hdg, and atzB genes, which encode for hydratase, dehalogenase, and ethylaminohydrolase, were found to be the most abundant genes involved in DDT, HCH, and ATZ degradation, respectively. The identified 69 genera capable of degrading organic pollutants were mostly affiliated with Proteobacteria (49.3%) and Actinobacteria (21.7%). Four genera, including Plesiocystis, Anaerolinea, Jannaschia, and Mycobacterium, were the major biodegradation populations in all sediments. In this study, the nearly complete biodegradation pathways of DDT and ATZ were found, and the partial degradation pathway of HCH was detected in all sediments.

  6. The in vitro influence of the burrowing polychaete Nereis diversicolor on the fate of petroleum hydrocarbons in marine sediments

    OpenAIRE

    Gilbert, Franck; Rivet, Lucien; Bertrand, Jean-Claude

    1994-01-01

    International audience The in vitro fate of the saturated hydrocarbon fraction (SF) of Arabian Light crude oil has been studied in PVC cores filled with a coastal marine sediment defaunated by sieving. Experiments were conducted in absence or presence of polychaetes Nereis diversicolor. The luminophore tracer technique was used to quantify the mixing of sediment by worms. Presence of crude oil reduced the building of burrows by polychaetes. This work demonstrates the ability of infaunal or...

  7. Interstitial solutions and diagenesis in deeply buried marine sediments: results from the Deep Sea Drilling Project

    Science.gov (United States)

    Sayles, F.L.; Manheim, F. T.

    1975-01-01

    Through the Deep Sea Drilling Project samples of interstitial solutions of deeply buried marine sediments throughout the World Ocean have been obtained and analyzed. The studies have shown that in all but the most slowly deposited sediments pore fluids exhibit changes in composition upon burial. These changes can be grouped into a few consistent patterns that facilitate identification of the diagenetic reactions occurring in the sediments. Pelagic clays and slowly deposited (recrystallization of biogenic calcite and the substitution of Mg2+ for Ca2+ during this reaction. The Ca-Mg-carbonate formed is most likely a dolomitic phase. A related but more complex pattern is found in carbonate sediments deposited at somewhat greater rates. Ca2+ and Sr2+ enrichment is again characteristic, but Mg2+ losses exceed Ca2+ gains with the excess being balanced by SO4post staggered2- losses. The data indicate that the reactions are similar to those noted above, except that the Ca2+ released is not kept in solution but is precipitated by the HCO3post staggered- produced in SO4post staggered2- reduction. In both these types of pore waters Na+ is usually conservative, but K+ depletions are frequent. In several partly consolidated sediment sections approaching igneous basement contact, very marked interstitial calcium enrichment has been found (to 5.5 g/kg). These phenomena are marked by pronounced depletion in Na+, Si and CO2, and slight enhancement in Cl-. The changes are attributed to exchange of Na+ for Ca2+ in silicate minerals forming from submarine weathering of igneous rocks such as basalts. Water is also consumed in these reactions, accounting for minor increases in total interstitial salinity. Terrigenous, organic-rich sediments deposited rapidly along continental margins also exhibit significant evidences of alteration. Microbial reactions involving organic matter lead to complete removal of SO4post staggered2-, strong HCO3post staggered- enrichment, formation of NH4post

  8. Experimental approaches to marine and meteoric dissolution-to-repreciptiation cycles of fine-grained marine carbonate sediments

    Science.gov (United States)

    Immenhauser, Adrian; Buhl, Dieter; Riechelmann, Sylvia; Kwiecien, Ola; Lokier, Stephen; Neuser, Rolf

    2016-04-01

    Fine-grained carbonate (carbonate ooze), or microcrystalline carbonate (micrite), its lithified counterpart, forms a main constituent of limestones throughout much of Earth's history. Fine-grained carbonates are deposited below the permanent fair-weather wave base in neritic lagoonal environments or below the storm-wave base in basinal settings. The origin of components forming these fine-grained carbonates often remains poorly understood and represents a major challenge in carbonate sedimentology, particularly when these materials are used as carbonate archives (bulk micrite geochemistry). Here we present a novel experimental approach exposing natural, fine-grained carbonate sediments to dissolution-reprecipitation cycles under non-sterile conditions that mimick earth-surface conditions. In a first stage, the experiment simulated subaerial exposure of an ooid (aragonite) shoal and leaching and carbonate dissolution under meteoric phreatic conditions. In a second stage, CO2 was added to the experimental fluid (natural rainwater) representing soil-zone activity. In a third stage, partly dissolved (micro-karstified) sediments were exposed to marine phreatic conditions simulating renewed flooding of the shoal carbonates. During the third stage, precipitation was induced by degassing the CO2 in the fluid with N2. Degassing induced nucleation and growth of a diagenetic inorganic aragonite (and subordinate calcite) phase upon the surface of carbonate particles. The outcome of these first experiments is promising. The CO2 concentration of the fluid and the air are low under atmospheric conditions and increase as expected due to adding CO2 to the experiment resulting in a lower pH. Carbonate dissolution increases conductivity, alkalinity, and calcium concentration reaching a plateau at the end of the first experimental phase. Small surficial damages to ooids represent zones of weakness and form the preferred sites of dissolution leading to a deepening and widening of these

  9. Regional Modelling of Air Quality in the Canadian Arctic: Impact of marine shipping and North American wild fire emissions

    Science.gov (United States)

    Gong, W.; Beagley, S. R.; Zhang, J.; Cousineau, S.; Sassi, M.; Munoz-Alpizar, R.; Racine, J.; Menard, S.; Chen, J.

    2015-12-01

    Arctic atmospheric composition is strongly influenced by long-range transport from mid-latitudes as well as processes occurring in the Arctic locally. Using an on-line air quality prediction model GEM-MACH, simulations were carried out for the 2010 northern shipping season (April - October) over a regional Arctic domain. North American wildfire emissions and Arctic shipping emissions were represented, along with other anthropogenic and biogenic emissions. Sensitivity studies were carried out to investigate the principal sources and processes affecting air quality in the Canadian Northern and Arctic regions. In this paper, we present an analysis of sources, transport, and removal processes on the ambient concentrations and atmospheric loading of various pollutants with air quality and climate implications, such as, O3, NOx, SO2, CO, and aerosols (sulfate, black carbon, and organic carbon components). Preliminary results from a model simulation of a recent summertime Arctic field campaign will also be presented.

  10. Basal mercury concentrations and biomagnification rates in freshwater and marine food webs: Effects on Arctic charr (Salvelinus alpinus) from eastern Canada

    Energy Technology Data Exchange (ETDEWEB)

    Velden, S. van der, E-mail: sdorn@uwaterloo.ca [Department of Biology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1 (Canada); Dempson, J.B. [Fisheries and Oceans Canada, St. John' s, Newfoundland and Labrador, Canada, A1C 5X1 (Canada); Evans, M.S. [Environment Canada, Saskatoon, Saskatchewan, Canada, S7N 3H5 (Canada); Muir, D.C.G. [Environment Canada, Burlington, Ontario, Canada, L7R 4A6 (Canada); Power, M., E-mail: m3power@uwaterloo.ca [Department of Biology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1 (Canada)

    2013-02-01

    Patterns of total Hg (THg) and methyl Hg (MeHg) biomagnification were investigated in six pairs of co-located lacustrine and marine food webs supporting a common predator, Arctic charr. Mercury biomagnification rates (the slope of log Hg concentration versus δ{sup 15}N-inferred trophic level) did not differ significantly between the two feeding habitats for either THg or MeHg, but THg and MeHg concentrations at the base of the food web were higher in the lacustrine environment than in the marine environment. The proportion of THg as MeHg was related to trophic level, and the relationship was statistically similar in the lacustrine and marine habitats. The biomagnification rate of MeHg exceeded that of THg in both habitats. We conclude that the known difference in Hg concentration between anadromous and non-anadromous Arctic charr is driven by differential Hg concentrations at the base of the lacustrine and marine foodwebs, and not by differential biomagnification rates. - Highlights: ► Concentrations of total mercury ([THg]) and methylmercury ([MeHg]) were measured in 6 paired lacustrine and marine food webs. ► Biomagnification rates (slopes of [THg] or [MeHg] versus δ{sup 15}N-inferred trophic level) were similar in the two habitat types. ► Mercury concentrations at the base of the food web were higher in lacustrine than in marine food webs. ► The percentage of methylated mercury increased with trophic level similarly in the two habitat types. ► The biomagnification rate of MeHg exceeded that of THg in both habitats.

  11. Basal mercury concentrations and biomagnification rates in freshwater and marine food webs: Effects on Arctic charr (Salvelinus alpinus) from eastern Canada

    International Nuclear Information System (INIS)

    Patterns of total Hg (THg) and methyl Hg (MeHg) biomagnification were investigated in six pairs of co-located lacustrine and marine food webs supporting a common predator, Arctic charr. Mercury biomagnification rates (the slope of log Hg concentration versus δ15N-inferred trophic level) did not differ significantly between the two feeding habitats for either THg or MeHg, but THg and MeHg concentrations at the base of the food web were higher in the lacustrine environment than in the marine environment. The proportion of THg as MeHg was related to trophic level, and the relationship was statistically similar in the lacustrine and marine habitats. The biomagnification rate of MeHg exceeded that of THg in both habitats. We conclude that the known difference in Hg concentration between anadromous and non-anadromous Arctic charr is driven by differential Hg concentrations at the base of the lacustrine and marine foodwebs, and not by differential biomagnification rates. - Highlights: ► Concentrations of total mercury ([THg]) and methylmercury ([MeHg]) were measured in 6 paired lacustrine and marine food webs. ► Biomagnification rates (slopes of [THg] or [MeHg] versus δ15N-inferred trophic level) were similar in the two habitat types. ► Mercury concentrations at the base of the food web were higher in lacustrine than in marine food webs. ► The percentage of methylated mercury increased with trophic level similarly in the two habitat types. The biomagnification rate of MeHg exceeded that of THg in both habitats

  12. Isolation and Characterization of Gram-Positive Piezophilic Bacteria from Deep Marine Subsurface Sediment

    Science.gov (United States)

    Runko, G. M.; Fang, J.; Kato, C.

    2014-12-01

    The marine deep biosphere remains as the least studied of all of Earth's habitats and is inadequately understood, but is extremely important to understand the impacts that microbes have on global biogeochemical cycles. Sediment samples were obtained during IODP Expedition 337 in the western Pacific Ocean, from 1,498 meters below the seafloor (mbsf; samples 6R3), 1,951-1,999 mbsf (19R1), and 2,406 mbsf (29R7). These samples were initially mixed with marine broth and cultivated under anaerobic conditions at pressure of 35 MPa (megapascal) and temperatures of 35° C, 45° C, and 55° C for 3 months on board the Chikyu. Single colonies were isolated via plating on marine broth. Then, six strains of bacteria were identified, 6R3-1, 6R3-15, 19R1-5, 29R7-12B, 29R7-12M, and 29R7-12S. The six strains were then examined for optimal growth temperature and pressure. These organisms are Gram-positive, spore-forming, facultative anaerobic piezophilic bacteria. Major fatty acids are anteiso-15:0, anteiso-17:0 and iso-15:0. Phylogenetic analysis of 16S rRNA gene sequences revealed that the isolates are closely related to Virgibacillus pantothenticus, Robinsoniella peoriensis, and Bacillus subtilis. Because of their abundance in the deep marine subsurface, these microorganisms likely play an important role in sustaining the deep microbial ecosystem and influencing biogeochemical cycles in the deep biosphere.

  13. Avoiding whales and wellheads: technology lightens impact of marine seismic on fragile Arctic ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Eaton, S.

    2001-09-01

    To minimize environmental impact, Anderson Exploration Ltd and WesternGeco are using new technologies that include state-of-the-art satellite systems for tracking whales, icebergs, ships and aircraft, and a pollutant-free means of keeping the streamers, or marine recording cables, from sinking. Using WesternGeco's satellite-based vehicle tracking system (VTS), ground personnel at a base camp can instantaneously determine the whereabouts of the icebreaker {sup G}eco Snapper' and the company's two vessels surveying the ocean floor. In the air, the VTS tracks the flight paths and altitudes of WesternGeco's Bell 212 helicopter and Twin Otter planes used to monitor whales and icebergs. From the bridge of the Geco Snapper, using GPS units located on the six air gun arrays and the three marine streamers which extend four kms behind the vessel, data are recorded in real time on the positions of the data acquisition equipment relative to the vessel and relative to water depth or proximity to the sea floor. The Geco Snapper has been retrofitted with the VTS equipment in preparation for its participation in a project for acquiring what may be the first-ever seismic survey in the frigid waters of the Beaufort Sea. Instead of being filled with gasoline, the streamers trailing the vessel are foam-filled, consequently, they are extremely safe and environmentally friendly.

  14. Rapid Environmental Change Drives Increased Land Use by an Arctic Marine Predator.

    Science.gov (United States)

    Atwood, Todd C; Peacock, Elizabeth; McKinney, Melissa A; Lillie, Kate; Wilson, Ryan; Douglas, David C; Miller, Susanne; Terletzky, Pat

    2016-01-01

    In the Arctic Ocean's southern Beaufort Sea (SB), the length of the sea ice melt season (i.e., period between the onset of sea ice break-up in summer and freeze-up in fall) has increased substantially since the late 1990s. Historically, polar bears (Ursus maritimus) of the SB have mostly remained on the sea ice year-round (except for those that came ashore to den), but recent changes in the extent and phenology of sea ice habitat have coincided with evidence that use of terrestrial habitat is increasing. We characterized the spatial behavior of polar bears spending summer and fall on land along Alaska's north coast to better understand the nexus between rapid environmental change and increased use of terrestrial habitat. We found that the percentage of radiocollared adult females from the SB subpopulation coming ashore has tripled over 15 years. Moreover, we detected trends of earlier arrival on shore, increased length of stay, and later departure back to sea ice, all of which were related to declines in the availability of sea ice habitat over the continental shelf and changes to sea ice phenology. Since the late 1990s, the mean duration of the open-water season in the SB increased by 36 days, and the mean length of stay on shore increased by 31 days. While on shore, the distribution of polar bears was influenced by the availability of scavenge subsidies in the form of subsistence-harvested bowhead whale (Balaena mysticetus) remains aggregated at sites along the coast. The declining spatio-temporal availability of sea ice habitat and increased availability of human-provisioned resources are likely to result in increased use of land. Increased residency on land is cause for concern given that, while there, bears may be exposed to a greater array of risk factors including those associated with increased human activities. PMID:27249673

  15. Rapid Environmental Change Drives Increased Land Use by an Arctic Marine Predator

    Science.gov (United States)

    Atwood, Todd C.; Peacock, Elizabeth; McKinney, Melissa A.; Lillie, Kate; Wilson, Ryan; Douglas, David C.; Miller, Susanne; Terletzky, Pat

    2016-01-01

    In the Arctic Ocean’s southern Beaufort Sea (SB), the length of the sea ice melt season (i.e., period between the onset of sea ice break-up in summer and freeze-up in fall) has increased substantially since the late 1990s. Historically, polar bears (Ursus maritimus) of the SB have mostly remained on the sea ice year-round (except for those that came ashore to den), but recent changes in the extent and phenology of sea ice habitat have coincided with evidence that use of terrestrial habitat is increasing. We characterized the spatial behavior of polar bears spending summer and fall on land along Alaska’s north coast to better understand the nexus between rapid environmental change and increased use of terrestrial habitat. We found that the percentage of radiocollared adult females from the SB subpopulation coming ashore has tripled over 15 years. Moreover, we detected trends of earlier arrival on shore, increased length of stay, and later departure back to sea ice, all of which were related to declines in the availability of sea ice habitat over the continental shelf and changes to sea ice phenology. Since the late 1990s, the mean duration of the open-water season in the SB increased by 36 days, and the mean length of stay on shore increased by 31 days. While on shore, the distribution of polar bears was influenced by the availability of scavenge subsidies in the form of subsistence-harvested bowhead whale (Balaena mysticetus) remains aggregated at sites along the coast. The declining spatio-temporal availability of sea ice habitat and increased availability of human-provisioned resources are likely to result in increased use of land. Increased residency on land is cause for concern given that, while there, bears may be exposed to a greater array of risk factors including those associated with increased human activities. PMID:27249673

  16. Rapid Environmental Change Drives Increased Land Use by an Arctic Marine Predator.

    Directory of Open Access Journals (Sweden)

    Todd C Atwood

    Full Text Available In the Arctic Ocean's southern Beaufort Sea (SB, the length of the sea ice melt season (i.e., period between the onset of sea ice break-up in summer and freeze-up in fall has increased substantially since the late 1990s. Historically, polar bears (Ursus maritimus of the SB have mostly remained on the sea ice year-round (except for those that came ashore to den, but recent changes in the extent and phenology of sea ice habitat have coincided with evidence that use of terrestrial habitat is increasing. We characterized the spatial behavior of polar bears spending summer and fall on land along Alaska's north coast to better understand the nexus between rapid environmental change and increased use of terrestrial habitat. We found that the percentage of radiocollared adult females from the SB subpopulation coming ashore has tripled over 15 years. Moreover, we detected trends of earlier arrival on shore, increased length of stay, and later departure back to sea ice, all of which were related to declines in the availability of sea ice habitat over the continental shelf and changes to sea ice phenology. Since the late 1990s, the mean duration of the open-water season in the SB increased by 36 days, and the mean length of stay on shore increased by 31 days. While on shore, the distribution of polar bears was influenced by the availability of scavenge subsidies in the form of subsistence-harvested bowhead whale (Balaena mysticetus remains aggregated at sites along the coast. The declining spatio-temporal availability of sea ice habitat and increased availability of human-provisioned resources are likely to result in increased use of land. Increased residency on land is cause for concern given that, while there, bears may be exposed to a greater array of risk factors including those associated with increased human activities.

  17. Effects of pollution on the geochemical properties of marine sediments across the fringing reef of Aqaba, Red Sea.

    Science.gov (United States)

    Al-Rousan, Saber; Al-Taani, Ahmed A; Rashdan, Maen

    2016-09-15

    The Gulf of Aqaba is of significant strategic and economic value to all gulf-bordering states, particularly to Jordan, where it provides Jordan with its only marine outlet. The Gulf is subject to a variety of impacts posing imminent ecological risk to its unique marine ecosystem. We attempted to investigate the status of metal pollution in the coastal sediments of the Jordanian Gulf of Aqaba. The distribution of Cd, Cr, Zn, Cu, Pb, Al, Fe, and Mn concentrations were determined in trapped and bottom-surface sediments at three selected sites at different depths. In addition, monthly sedimentation rates at varying water depths were also estimated at each sampling site using sediment traps. The high concentrations of Cd, Cr, Zn were recorded at the Phosphate Loading Birth (PLB) site followed by the Industrial Complex (IC) site indicating their dominant anthropogenic source (i.e., the contribution of industrial activities). However, Fe, Al, and Mn contents were related to inputs from the terrigenous (crustal) origin. Except for Al, Fe and Mn at the PLB site, the concentrations of metals exhibited a decreasing trend with increasing water depth (distance from the shoreline). The PLB site also showed the highest sedimentation rate which decreased with increasing water depth. The Enrichment factors (EFs) showed that Cd was the most enriched element in the sediment (indicating that Cd pollution is widespread), whereas the least enriched metal in sediments was Cu. EF values suggested that the coastal area is impacted by a combination of human and natural sources of metals, where the anthropogenic sources are intense in the PLB site (north of Gulf of Aqaba). The MSS area is potentially the least polluted, consistent with being a marine reserve. The IC sediments have been found to be impacted by human activities but less intensely compared to the PLB area. These results suggested that there are two sources of metals in sediments; the primary source is likely closer to PLB

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

    Directory of Open Access Journals (Sweden)

    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.

  19. Fungal diversity from deep marine subsurface sediments (IODP 317, Canterbury Basin, New Zealand)

    Science.gov (United States)

    Redou, V.; Arzur, D.; Burgaud, G.; Barbier, G.

    2012-12-01

    Recent years have seen a growing interest regarding micro-eukaryotic communities in extreme environments as a third microbial domain after Bacteria and Archaea. However, knowledge is still scarce and the diversity of micro-eukaryotes in such environments remains hidden and their ecological role unknown. Our research program is based on the deep sedimentary layers of the Canterbury Basin in New Zealand (IODP 317) from the subsurface to the record depth of 1884 meters below seafloor. The objectives of our study are (i) to assess the genetic diversity of fungi in deep-sea sediments and (ii) identify the functional part in order to better understand the origin and the ecological role of fungal communities in this extreme ecosystem. Fingerprinting-based methods using capillary electrophoresis single-strand conformation polymorphism and denaturing high-performance liquid chromatography were used as a first step to raise our objectives. Molecular fungal diversity was assessed using amplification of ITS1 (Internal Transcribed Spacer 1) as a biomarker on 11 samples sediments from 3.76 to 1884 meters below seafloor. Fungal molecular signatures were detected throughout the sediment core. The phyla Ascomycota and Basidiomycota were revealed with DNA as well as cDNA. Most of the phylotypes are affiliated to environmental sequences and some to common fungal cultured species. The discovery of a present and metabolically active fungal component in this unique ecosystem allows some interesting first hypotheses that will be further combined to culture-based methods and deeper molecular methods (454 pyrosequencing) to highlight essential informations regarding physiology and ecological role of fungal communities in deep marine sediments.

  20. Factors that control the stable carbon isotopic composition of methane produced in an anoxic marine sediment

    Science.gov (United States)

    Alperin, M. J.; Blair, Neal E.; Albert, D. B.; Hoehler, T. M.; Martens, C. S.

    1993-01-01

    The carbon isotopic composition of methane produced in anoxic marine sediment is controlled by four factors: (1) the pathway of methane formation, (2) the isotopic composition of the methanogenic precursors, (3) the isotope fractionation factors for methane production, and (4) the isotope fractionation associated with methane oxidation. The importance of each factor was evaluated by monitoring stable carbon isotope ratios in methane produced by a sediment microcosm. Methane did not accumulate during the initial 42-day period when sediment contained sulfate, indicating little methane production from 'noncompetitive' substrates. Following sulfate depletion, methane accumulation proceeded in three distinct phases. First, CO2 reduction was the dominant methanogenic pathway and the isotopic composition of the methane produced ranged from -80 to -94 per thousand. The acetate concentration increased during this phase, suggesting that acetoclastic methanogenic bacteria were unable to keep pace with acetate production. Second, acetate fermentation became the dominant methanogenic pathway as bacteria responded to elevated acetate concentrations. The methane produced during this phase was progressively enriched in C-13, reaching a maximum delta(C-13) value of -42 per thousand. Third, the acetate pool experienced a precipitous decline from greater than 5 mM to less than 20 micro-M and methane production was again dominated by CO2 reduction. The delta(C-13) of methane produced during this final phase ranged from -46 to -58 per thousand. Methane oxidation concurrent with methane production was detected throughout the period of methane accumulation, at rates equivalent to 1 to 8 percent of the gross methane production rate. Thus methane oxidation was too slow to have significantly modified the isotopic signature of methane. A comparison of microcosm and field data suggests that similar microbial interactions may control seasonal variability in the isotopic composition of methane

  1. [Guest article:] Marine sediments as a high-resolution archive of climate variability

    International Nuclear Information System (INIS)

    The 'debate' in the global climate debate arises partly because of uncertainty about natural variability in global climate. The instrumental record (daily temperature, pressure and rainfall measurements, supplemented more recently by satellite imagery, upper atmospheric monitors and marine buoys) only extends back to the middle of the nineteenth century, and the perennial question is how certain can we be that this record contains all possible or relevant variation? To look further back in time, researchers in the discipline of palaeoclimatology study records (proxies) of climate change preserved in rock, sediment or biological materials. A well-known example of a proxy in the natural environment would be the changes in the thickness or density of tree rings in response to changes in precipitation. Most individual proxies have ambiguous interpretations with respect to climate and it is necessary to investigate several from the one location (called a multiproxy study) in order to unravel the complete story. To construct a global picture of prehistoric climate change, scientists must study proxies from a range of sur