WorldWideScience

Sample records for marine sediment reference

  1. delta 15N and non-carbonate delta 13C values for two petroleum source rock reference materials and a marine sediment reference material

    Science.gov (United States)

    Dennen, Kristin O.; Johnson, Craig A.; Otter, Marshall L.; Silva, Steven R.; Wandless, Gregory A.

    2006-01-01

    Samples of United States Geological Survey (USGS) Certified Reference Materials USGS Devonian Ohio Shale (SDO-1), and USGS Eocene Green River Shale (SGR-1), and National Research Council Canada (NRCC) Certified Marine Sediment Reference Material (PACS-2), were sent for analysis to four separate analytical laboratories as blind controls for organic rich sedimentary rock samples being analyzed from the Red Dog mine area in Alaska. The samples were analyzed for stable isotopes of carbon (delta13Cncc) and nitrogen (delta15N), percent non-carbonate carbon (Wt % Cncc) and percent nitrogen (Wt % N). SDO-1, collected from the Huron Member of the Ohio Shale, near Morehead, Kentucky, and SGR-1, collected from the Mahogany zone of the Green River Formation are petroleum source rocks used as reference materials for chemical analyses of sedimentary rocks. PACS-2 is modern marine sediment collected from the Esquimalt, British Columbia harbor. The results presented in this study are, with the exceptions noted below, the first published for these reference materials. There are published information values for the elemental concentrations of 'organic' carbon (Wt % Corg measured range is 8.98 - 10.4) and nitrogen (Wt % Ntot 0.347 with SD 0.043) only for SDO-1. The suggested values presented here should be considered 'information values' as defined by the NRCC Institute for National Measurement Reference Materials and should be useful for the analysis of 13C, 15N, C and N in organic material in sedimentary rocks.

  2. Application of Isotope Dilution Mass Spectrometry for Reference Measurements of Cadmium. Copper, Mercury, Lead, Zinc and Methyl Mercury in Marine Sediment Sample

    Directory of Open Access Journals (Sweden)

    Vasileva E.

    2013-04-01

    Full Text Available Marine sediment was selected as a test sample for the laboratory inter-comparison studies organized by the Environment Laboratoryes of the International Atomic Energy. The analytical procedure to establish the reference values for the Cd, Cu, Hg, Methyl Hg, Pb and Zn amount contents was based on Isotope Dilution Inductively Coupled Plasma-Mass Spectrometry (ID ICP-MS applied as a primary method of measurement..The Hg and Methyl Hg determination will be detailed more specifically because of the problems encountered with this element, including sample homogeneity issues, memory effects and possible matrix effects during the ICP- MS measurement stage. Reference values, traceable to the SI, with total uncertainties of less than 2% relative expanded uncertainty (k=2 were obtained for Cd, Cu, Zn and Pb and around 5% for Hg and CH3Hg.

  3. Marine Reference Materials

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Various publications and other instructions for taking marine weather observations. includes Weather Service Observing Handbook No. 1, Weather Bureau Circular M, and...

  4. 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

  5. Principles of Geological Mapping of Marine Sediments (with Special Reference to the African Continental Margin). Unesco Reports in Marine Science No. 37.

    Science.gov (United States)

    Lisitzin, Alexandre P.

    Designed to serve as a complement to the Unesco Technical Papers in Marine Science, this report concentrates on theoretical and practical problems of geological mapping of the sea floor. An introduction is given to geological mapping procedures at continental margins as well as some practical recommendations taking as an example the African region…

  6. Dispersion of Sound in Marine Sediments

    Science.gov (United States)

    2014-09-30

    Marine Geology , 209, 147-172, (2004). Jiang, Y. and N.R. Chapman. The Impact of Ocean Sound Speed Variability on the Uncertainty of Geoacoustic...1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Dispersion of Sound in Marine Sediments N. Ross...our understanding of the interaction of sound with the ocean bottom is the frequency dependence of sound speed and attenuation in marine sediments

  7. Isolation of Cellulolytic Actinomycetes from Marine Sediments

    OpenAIRE

    Veiga, Manuel; Esparis, Azucena; Fabregas, Jaime

    1983-01-01

    The cellulolytic activity of 36 actinomycetes strains isolated from marine sediments was investigated by the cellulose-azure method. Approximately 50% of the isolates exhibited various degrees of cellulolytic activity.

  8. Chlorinated pesticide residues in marine sediments

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.; SenGupta, R.

    A number of organochlorine pesticides residues, aldrine, gamma BHC, dieldrine, and DDT were detected and quantified from the marine sediments collected along the east coast of India by gas chromatography using an electron capture detector. Almost...

  9. Marine Mammal Food Habits Reference Collections

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) Food Habits Reference Collection, containing over 8000 specimens of cephalopod beaks and fish bones and otoliths, is...

  10. 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

  11. Design of a marine sediment trap and accessories

    Digital Repository Service at National Institute of Oceanography (India)

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

    The marine sediment trap and the mooring accessories were developed indigenously and were used successfully for the collection of settling sediments in the Arabian Sea The experience gained in using sediment trap and further improvements...

  12. 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...

  13. Sediment Burial Intolerance of Marine Macroinvertebrates

    OpenAIRE

    Hendrick, Vicki J.; Hutchison, Zoë L.; Last, Kim S.

    2016-01-01

    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 fract...

  14. Carotenoid diagenesis in a marine sediment

    Science.gov (United States)

    Watts, C. D.; Maxwell, J. R.

    1977-01-01

    The major carotenoids at three levels (3, 40, and 175 m below the sediment-water interface) in a core from a marine sediment (Cariaco Trench, off Venezuela) have been examined. Mass and electronic spectral data have provided evidence for the onset of a progressive reduction of carotenoids in the geological column. The time scale of the process appears to depend on the particular carotenoid. Reduction of up to two double bonds is observed for the diol, zeaxanthin, in the oldest sediment (about 340,000 years old) but no reduction is observed in the younger samples (about 5000 and 56,000 years old). The diketone, canthaxanthin, shows evidence of reduction of up to two double bonds in the 56,000-yr sample and up to five double bonds in the oldest sample. No reduction of beta-carotene was observed in any of the samples.

  15. 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.

  16. Nonlinear acoustics of water-saturated marine sediments

    DEFF Research Database (Denmark)

    Jensen, Leif Bjørnø

    1976-01-01

    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...... available for fluids to a few being used for a determination of the nonlinear acoustic parameters of water-saturated marine sediments. These test methods, comprising static, thermodynamic and finite-amplitude wave distortion and absorption methods, aiming at a determination of B/A for marine sediments...

  17. Copper isotope signatures in modern marine sediments

    Science.gov (United States)

    Little, Susan H.; Vance, Derek; McManus, James; Severmann, Silke; Lyons, Timothy W.

    2017-09-01

    The development of metal stable isotopes as tools in paleoceanography requires a thorough understanding of their modern marine cycling. To date, no Cu isotope data has been published for modern sediments deposited under low oxygen conditions. We present data encompassing a broad spectrum of hydrographic and redox regimes, including continental margin and euxinic (sulphide-containing) settings. Taken together with previously published data from oxic settings, these data indicate that the modern oceanic sink for Cu has a surprisingly homogeneous isotopic composition of about +0.3‰ (δ65Cu, relative to NIST SRM976). We suggest that this signature reflects one of two specific water-column processes: (1) an equilibrium isotope fractionation between soluble, isotopically heavy, Cu complexed to strong organic ligands and an isotopically light pool sorbed to particles that deliver Cu to the sediment, or (2) an equilibrium isotope fractionation between the same isotopically heavy ligand-bound pool and the particle reactive free Cu2+ species, with the latter being scavenged by particulates and thereby delivered to the sediment. An output flux of about +0.3‰ into sediments is isotopically light relative to the known inputs to the ocean (at around +0.6‰) and the seawater value of +0.6 to +0.9‰, suggesting the presence of an as yet unidentified isotopically light source of Cu to the oceans. We hypothesize that this source may be hydrothermal, or may result from the partial dissolution of continentally derived particles.

  18. 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

  19. Microbial bioavailability regulates organic matter preservation in marine sediments

    NARCIS (Netherlands)

    Koho, K.A.; Nierop, K.G.J.; Moodley, L.; Middelburg, J.J.; Pozzato, L.; Soetaert, K.; van der Plicht, J.; Reichart, G.J.

    2013-01-01

    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

  20. 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

  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. Bulkgeochemical (C : N ratio and stable carbon isotopic composition) parameters sug

  2. Sorption behavior of o-nitrophenol on marine sediment

    Institute of Scientific and Technical Information of China (English)

    YANG Guipeng; WU Ping; KONG Dexin

    2005-01-01

    Systematic study on sorption behavior of o-nitrophenol on marine sediments was conducted.Isotherms of sorption of o-nitrophenol on marine sediments could be described by Freundlich model; and the isotherm of sorption of o-nitrophenol on HCl-treated sediment could be described by Langmuir model. The sorption behavior was affected by various factors including organic carbon content, aqueous solution salinity,temperature, and acidity. The sorption amount of o-nitrophenol increased when salinity and acidity of the aqueous solution increase, but decreased with increasing temperature. Organic carbon content in sediments had apparent effect on the behavior except for HCl-treated sediments.

  3. Critical State Sedimentation Line of Soft Marine Clays

    Institute of Scientific and Technical Information of China (English)

    HONG Zhen-shun(洪振舜); LIU Han-long(刘汉龙); CHANG Nien-yin

    2003-01-01

    The compression behavior responsible for unity sensitivity is very valuable in quantitative assessment of the effects of soil structure on the compression behavior of soft marine sediments. However, the quantitative assessment of such effects is not possible because of unavailability of the formula for the compression curve of marine sediments responsible for unit sensitivity. In this study, the relationship between the remolded state and the conventional critical state line is presented in the deviator stress versus mean effective stress plot. The analysis indicates that the remolded state is on the conventional critical state line obtained at a relatively small strain. Thus, a unique critical state sedimentation line for marine sediments of unit sensitivity is proposed. The comparison between the critical state sedimentation line proposed in this study and the existing normalized consolidation curves obtained from conventional oedometer tests on remolded soils or reconstituted soils explains well the effects of initial water content on the oedometer consolidation curves for remolded soils.

  4. Acoustic Wave Dispersion and Scattering in Complex Marine Sediment Structures

    Science.gov (United States)

    2015-09-30

    Acoustic wave dispersion and scattering in complex marine sediment structures Charles W. Holland The Pennsylvania State University Applied...volume scattering and 2) the effects of shear waves in general layered media. These advances will provide the basis for measuring dispersion in in-situ...shear waves on dispersion in marine sediments. The first step will be development of the theory. WORK COMPLETED A brief summary of the work

  5. 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

  6. A model for microbial phosphorus cycling in bioturbated marine sediments

    DEFF Research Database (Denmark)

    Dale, Andrew W.; Boyle, R. A.; Lenton, Timothy M.

    2016-01-01

    A diagenetic model is used to simulate the diagenesis and burial of particulate organic carbon (Corg) and phosphorus (P) in marine sediments underlying anoxic versus oxic bottom waters. The latter are physically mixed by animals moving through the surface sediment (bioturbation) and ventilated by...

  7. 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.

  8. Development of marine sediment toxicity identification evaluation methods using Strongylocentrotus purpuratus, Mytilus edulis, and Eohaustorius estuarius

    Energy Technology Data Exchange (ETDEWEB)

    Wortham, G.; Cotsifas, J.S.; Taberski, K.; Hansen, S.R. [S.R. Hansen and Associates, Concord, CA (United States)

    1994-12-31

    Widespread sediment toxicity, including ``clean`` reference sites, dictates that the causes of toxicity in sediments be determined. Toxicity Identification Evaluations (TIE) are useful tools in characterizing compounds responsible for toxicity, but were unavailable for sediment samples. TIE methods were developed for sediment porewater and included the following components: determination of an appropriate porewater extraction process; control TIE tests using marine water and porewater evaluating species sensitivities to the fractionation procedures; validation experiments investigating the removal efficiencies of organics using C18 solid phase extraction, and metals chelation using EDTA and STS; spiking experiments to determine the effectiveness of the TIE procedure in identifying multiple toxicants. The authors determined that fractionation procedures could be applied to both marine water and porewater using S. purpuratus, M. edulis and E. estuarius as biological detectors.

  9. Bacterial communities in sediment of a Mediterranean marine protected area.

    Science.gov (United States)

    Catania, Valentina; Sarà, Gianluca; Settanni, Luca; Quatrini, Paola

    2017-04-01

    Biodiversity is crucial in preservation of ecosystems, and bacterial communities play an indispensable role for the functioning of marine ecosystems. The Mediterranean marine protected area (MPA) "Capo Gallo-Isola delle Femmine" was instituted to preserve marine biodiversity. The bacterial diversity associated with MPA sediment was compared with that from sediment of an adjacent harbour exposed to intense nautical traffic. The MPA sediment showed higher diversity with respect to the impacted site. A 16S rDNA clone library of the MPA sediment allowed the identification of 7 phyla: Proteobacteria (78%), Firmicutes (11%), Acidobacteria (3%), Actinobacteria (3%), Bacteroidetes (2%), Planctomycetes (2%), and Cyanobacteria (1%). Analysis of the hydrocarbon (HC)-degrading bacteria was performed using enrichment cultures. Most of the MPA sediment isolates were affiliated with Gram-positive G+C rich bacteria, whereas the majority of taxa in the harbour sediment clustered with Alpha- and Gammaproteobacteria; no Gram-positive HC degraders were isolated from the harbour sediment. Our results show that protection probably has an influence on bacterial diversity, and suggest the importance of monitoring the effects of protection at microbial level as well. This study creates a baseline of data that can be used to assess changes over time in bacterial communities associated with a Mediterranean MPA.

  10. 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.

  11. Occurrence and sorption properties of arsenicals in marine sediments

    DEFF Research Database (Denmark)

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

    2013-01-01

    with depth, dissolved oxygen (DO), salinity and sediment classification; for depths 9 mg/L and sand/silt/clay sediments the Kd was 118 ± 76 L/kg DM and for depths >70 m, salinity >11 %, DO ... from the Baltic Sea near the island of Bornholm at depths of up to 100 m. As(III+V) and DMA were detected in the sediment and As(III+V) was detected in the sediment pore water. Average total As concentration of 10.6 ± 7.4 mg/kg dry matter (DM) in the sediment corresponds to previously reported values...... 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...

  12. Reburial of fossil organic carbon in marine sediments

    OpenAIRE

    2004-01-01

    Marine sediments act as the ultimate sink for organic carbon, sequestering otherwise rapidly cycling carbon for geologic timescales. Sedimentary organic carbon burial appears to be controlled by oxygen exposure time in situ, and much research has focused on understanding the mechanisms of preservation of organic carbon. In this context, combustion-derived black carbon has received attention as a form of refractory organic carbon that may be preferentially preserved in soils and sediments. How...

  13. Reburial of fossil organic carbon in marine sediments

    OpenAIRE

    Dickens, Angela F.; Gélinas, Yves; Masiello, Caroline A.; Wakeham, Stuart; Hedges, John I.

    2004-01-01

    Marine sediments act as the ultimate sink for organic carbon, sequestering otherwise rapidly cycling carbon for geologic timescales. Sedimentary organic carbon burial appears to be controlled by oxygen exposure time in situ, and much research has focused on understanding the mechanisms of preservation of organic carbon. In this context, combustion-derived black carbon has received attention as a form of refractory organic carbon that may be preferentially preserved in soils and sediments. How...

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

    OpenAIRE

    Schauer, Regina; Risgaard-Petersen, Nils; Kjeldsen, Kasper U.; Tataru Bjerg, Jesper J; B Jørgensen, Bo; Schramm, Andreas; Nielsen, Lars Peter

    2014-01-01

    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 through...

  15. Ocean currents shape the microbiome of Arctic marine sediments.

    Science.gov (United States)

    Hamdan, Leila J; Coffin, Richard B; Sikaroodi, Masoumeh; Greinert, Jens; Treude, Tina; Gillevet, Patrick M

    2013-04-01

    Prokaryote communities were investigated on the seasonally stratified Alaska Beaufort Shelf (ABS). Water and sediment directly underlying water with origin in the Arctic, Pacific or Atlantic oceans were analyzed by pyrosequencing and length heterogeneity-PCR in conjunction with physicochemical and geographic distance data to determine what features structure ABS microbiomes. Distinct bacterial communities were evident in all water masses. Alphaproteobacteria explained similarity in Arctic surface water and Pacific derived water. Deltaproteobacteria were abundant in Atlantic origin water and drove similarity among samples. Most archaeal sequences in water were related to unclassified marine Euryarchaeota. Sediment communities influenced by Pacific and Atlantic water were distinct from each other and pelagic communities. Firmicutes and Chloroflexi were abundant in sediment, although their distribution varied in Atlantic and Pacific influenced sites. Thermoprotei dominated archaea in Pacific influenced sediments and Methanomicrobia dominated in methane-containing Atlantic influenced sediments. Length heterogeneity-PCR data from this study were analyzed with data from methane-containing sediments in other regions. Pacific influenced ABS sediments clustered with Pacific sites from New Zealand and Chilean coastal margins. Atlantic influenced ABS sediments formed another distinct cluster. Density and salinity were significant structuring features on pelagic communities. Porosity co-varied with benthic community structure across sites and methane did not. This study indicates that the origin of water overlying sediments shapes benthic communities locally and globally and that hydrography exerts greater influence on microbial community structure than the availability of methane.

  16. Reburial of fossil organic carbon in marine sediments.

    Science.gov (United States)

    Dickens, Angela F; Gélinas, Yves; Masiello, Caroline A; Wakeham, Stuart; Hedges, John I

    2004-01-22

    Marine sediments act as the ultimate sink for organic carbon, sequestering otherwise rapidly cycling carbon for geologic timescales. Sedimentary organic carbon burial appears to be controlled by oxygen exposure time in situ, and much research has focused on understanding the mechanisms of preservation of organic carbon. In this context, combustion-derived black carbon has received attention as a form of refractory organic carbon that may be preferentially preserved in soils and sediments. However, little is understood about the environmental roles, transport and distribution of black carbon. Here we apply isotopic analyses to graphitic black carbon samples isolated from pre-industrial marine and terrestrial sediments. We find that this material is terrestrially derived and almost entirely depleted of radiocarbon, suggesting that it is graphite weathered from rocks, rather than a combustion product. The widespread presence of fossil graphitic black carbon in sediments has therefore probably led to significant overestimates of burial of combustion-derived black carbon in marine sediments. It could be responsible for biasing radiocarbon dating of sedimentary organic carbon, and also reveals a closed loop in the carbon cycle. Depending on its susceptibility to oxidation, this recycled carbon may be locked away from the biologically mediated carbon cycle for many geologic cycles.

  17. Reburial of fossil organic carbon in marine sediments

    Science.gov (United States)

    Dickens, Angela F.; Gélinas, Yves; Masiello, Caroline A.; Wakeham, Stuart; Hedges, John I.

    2004-01-01

    Marine sediments act as the ultimate sink for organic carbon, sequestering otherwise rapidly cycling carbon for geologic timescales. Sedimentary organic carbon burial appears to be controlled by oxygen exposure time in situ, and much research has focused on understanding the mechanisms of preservation of organic carbon. In this context, combustion-derived black carbon has received attention as a form of refractory organic carbon that may be preferentially preserved in soils and sediments. However, little is understood about the environmental roles, transport and distribution of black carbon. Here we apply isotopic analyses to graphitic black carbon samples isolated from pre-industrial marine and terrestrial sediments. We find that this material is terrestrially derived and almost entirely depleted of radiocarbon, suggesting that it is graphite weathered from rocks, rather than a combustion product. The widespread presence of fossil graphitic black carbon in sediments has therefore probably led to significant overestimates of burial of combustion-derived black carbon in marine sediments. It could be responsible for biasing radiocarbon dating of sedimentary organic carbon, and also reveals a closed loop in the carbon cycle. Depending on its susceptibility to oxidation, this recycled carbon may be locked away from the biologically mediated carbon cycle for many geologic cycles.

  18. Reference material for radionuclides in sediment IAEA-384 (Fangataufa Lagoon sediment)

    DEFF Research Database (Denmark)

    Povinec, P.P.; Pham, M.K.; Sanchez-Cabeza, J.A.;

    2007-01-01

    A reference material designed for the determination of anthropogenic and natural radionuclides in sediment, IAEA-384 (Fangataufa Lagoon sediment), is described and the results of certification are presented. The material has been certified for 8 radionuclides (K-40, Co-60, Eu-155, Th-230, U-238, ...

  19. 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...

  20. Mineralogical Signatures in Electrically Coupled Marine Sediments

    Science.gov (United States)

    Bauermeister, A.; Gorby, Y. A.; Schramm, J.

    2014-12-01

    'Electric cable bacteria' are organisms of the family Desulfobulbaceaethat exhibit a novel method of electron transport. Cells form conductive filaments that function like electric wires, transferring electrons over distances of more than 1 cm from deep sulfidic sediments to oxygen or other electron acceptors near the soil/water interface. The rate of electron transfer across redox boundaries far exceeds that of diffusion limited processes and generates pH gradients that can significantly influence geochemical reactions, leading to the formation of distinct mineralogical profiles unlikely to be created by abiotic means. Electrically coupled sediments are characterized by carbonate and iron sulfide dissolution reactions occurring at depth and formation of carbonate and metal oxide crusts at the surface, exhibiting a reverse pattern compared to conventional sediment geochemistry. Our research seeks to address the following questions: How prevalent are electric cable bacteria in diverse environments? How do biogeochemical conditions such as ion concentration influence mineral formation? Do biogenic minerals participate in charge transfer? What is the importance of electric charge transfer in the subsurface or other low energy habitats? Can mineral banding patterns caused by cable bacteria activity be preserved in the geologic record? With this research we hope to further elucidate the impact of biologically-induced electric fields on the mineralogy of sediments.

  1. Fast assessment of bioaccessible metallic contamination in marine sediments.

    Science.gov (United States)

    Terán-Baamonde, J; Carlosena, A; Soto-Ferreiro, R M; Andrade, J M; Prada, D

    2017-09-07

    A fast (16min) procedure to assess the bioaccessible metallic fraction of Cd, Cr, Cu, Ni, Pb and Zn simultaneously extracted (SEM) from marine sediments plus an indirect approach to determine acid volatile sulfides (AVS) are presented. For the extraction process magnetic agitation was compared with ultrasonic stirring (using a bath and a probe), and several stirring times were assayed. The proposed SEM procedure uses an ultrasonic probe and 1mL of HCl. It dramatically minimizes the turnaround time and the residues. AVS were evaluated as the difference between the amounts of sulphur in the solid residue after the extraction and total sulphur in the original sample. These procedures are fast, easy to implement and cost-effective to assess the potential risk posed by metals in marine sediments. They were tested using several CRMs and applied to sediments from two Galician Rias (NW Spain); their SEM-AVS differences indicated no biological risk. Copyright © 2017. Published by Elsevier Ltd.

  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. 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.

  4. 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

  5. Linking continental erosion to marine transport and sedimentation

    Science.gov (United States)

    Yuan, Xiaoping; Braun, Jean; Guerit, Laure

    2017-04-01

    Limited attention has been given to linking continental erosion to marine transport and sedimentation in large-scale landscape evolution models. Although either of the two environments has been thoroughly investigated, the details of how erosional events are recorded in the sedimentary and stratigraphic records have not been studied in a consistent quantitative manner. Here we present results obtained from a new numerical model for marine sediment transport and deposition that is directly coupled to FastScape, a landscape evolution model that solves the continental stream power law and hillslope diffusion equation using fully implicit and O(n) algorithms. The model of marine transport and sedimentation is simulated by a nonlinear 2D diffusion model where a source term represents mass flux arising from continental river erosion. It is based on the simplest representation of marine transport that assumes that flux is proportional to slope, which leads to a diffusion-type equation that we solve using an alternating direction implicit scheme. Multiple lithologies are implemented that vary by their transport coefficients. This method is also highly efficient (O(n) and implicit), which allows us to perform a large number of simulations to undertake a Bayesian inversion of stratigraphic data. Using our model we not only show the manner in which the stratigraphic record responds to tectonic and climate events but also how it is controlled by the coefficients for river erosion, hillslope diffusion, the transport coefficients in the ocean environment, and variations in sea level. The model is used to better constrain the nature and timing of erosional events on adjacent continents through an inversion of the stratigraphic record. In the longer term, we are looking at ways to improve the equations governing marine sediment transport especially, to better represent the deep part of that transport, i.e. in the abyssal plains or past the shelf and slope.

  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. 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.

  8. 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.

  9. 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.

  10. Manganese detection in marine sediments: anodic vs. cathodic stripping voltammetry.

    Science.gov (United States)

    Banks, Craig E; Kruusma, Jaanus; Moore, Ryan R; Tomcík, Peter; Peters, Judith; Davis, James; Komorsky-Lovrić, Sebojka; Compton, Richard G

    2005-01-30

    Three different electroanalytical techniques for the detection of manganese in marine sediments are evaluated. The anodic stripping voltammetry of manganese at an in situ bismuth-film-modified boron-doped diamond electrode and cathodic stripping voltammetry at a carbon paste electrode are shown to lack the required sensitivity and reproducibility whereas cathodic stripping voltammetry at a bare boron-doped diamond electrode is shown to be reliable and selective with a limit of detection, from applying a 60s accumulation period of 7.4 x 10(-7)M and a sensitivity of 0.24AM(-1). The method was used to evaluate the manganese content of marine sediments taken from Sibenik, Croatia.

  11. Guidelines for Marine Biological Reference Collections. Unesco Reports in Marine Sciences, No. 22.

    Science.gov (United States)

    Hureau, J. C.; Rice, A. L.

    This manual provides practical advice on the appropriation, conservation, and documentation of a marine biological reference collection, in response to needs expressed by Mediterranean Arab countries. A reference collection is defined as a working museum containing a series of specimens with which biologists are able to compare their own material.…

  12. Properties of bricks produced from Greenlandic marine sediments

    DEFF Research Database (Denmark)

    Bertelsen, Ida Maria Gieysztor; Belmonte, Louise Josefine; Chen, Wan

    2015-01-01

    This study investigated the possibility of a local brick production from fine grained marine sediments (MS) near Sisimiut, Greenland. The assessment is based on the physical and mechanical properties of clay bricks concerning the resistance to the harsh, Arctic weather conditions, together...... water to fulfil the requirements for severe weathering according to ASTM-C62 (2013). It was concluded that the firing temperature needed to be increased in order to obtain a more durable brick-type, suitable for the Arctic climate....

  13. Distribution of actinomycetes in near-shore tropical marine sediments.

    OpenAIRE

    Jensen, P.R.; Dwight, R; Fenical, W.

    1991-01-01

    Actinomycetes were isolated from near-shore marine sediments collected at 15 island locations throughout the Bahamas. A total of 289 actinomycete colonies were observed, and all but 6 could be assigned to the suprageneric groups actinoplanetes and streptomycetes. A bimodal distribution in the actinomycete population in relation to depth was recorded, with the maximum numbers occurring in the shallow and deep sampling sites. This distribution can be accounted for by a rapid decrease in strepto...

  14. Heterotrophic euglenids from marine sediments of cape tribulation, tropical australia

    Science.gov (United States)

    Je Lee, Won

    2006-06-01

    This paper presents new data on free-living heterotrophic euglenids (Euglenozoa, Protista) that occurred in the marine sediments at Cape Tribulation, Queensland, Australia. Twenty-nine species from 9 genera are described with uninterpreted records based on light microscopy, including one new taxon: Notosolenus capetribulationi n. sp. There was little evidence for endemism because the majority of heterotrophic euglenid species encountered here have been reported or were found from other habitats.

  15. 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

  16. {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.

  17. Spheroidal Carbonaceous Particles (SCPs) as Chronological Markers in Marine Sediments

    Science.gov (United States)

    Thornalley, D.; Rose, N.; Oppo, D.

    2016-12-01

    Spheroidal carbonaceous particles (SCPs) are a component of fly-ash, the particulate by-product of industrial high-temperature combustion of coal and fuel-oil that is released to the atmosphere with flue-gases. They are morphologically distinct and have no natural sources making them unambiguous markers of contamination from these anthropogenic sources. In naturally accumulating archives, SCPs may be used as a chronological tool as they provide a faithful record of industrial emissions and deposition. While the timing of the first presence of SCP in the 19th century, and the observed sub-surface peak are dependent on factors such as sediment accumulation rates and local industrial history, a rapid increase in SCP inputs in the mid-20thcentury appears to be a global signal corresponding to an acceleration in global electricity demand following the Second World War and the use of fuel-oil in electricity production at an industrial scale for the first time. While this approach has been widely used in lake sediments, it has not been applied to marine sediments, although there is great potential. Improved dating of 19th-20th century marine sediments has particular relevance for developing reconstructions of recent multi-decadal climate and ocean variability, and for studies that aim to place 20thcentury climate change within the context of the last millennium. Here, we present data from three sediment cores from the continental slope south of Iceland to demonstrate the temporal and spatial replicability of the SCP record in the marine environment and compare these data with cores taken from more contaminated areas off the coast of the eastern United States. The improved age model constraints provided by the analysis of SCPs has enabled a more accurate assessment of the timing of recent abrupt climate events recorded in these archives and has thus improved our understanding of likely causal climate mechanisms.

  18. Bioremediation of marine sediments impacted by petroleum.

    Science.gov (United States)

    da Silva, Aike C; de Oliveira, Fernando J S; Bernardes, Diogo S; de França, Francisca P

    2009-05-01

    The aim of this work was to optimize the bioremediation of crude oil-contaminated sand sediment through the biostimulation technique. The soil was obtained in the mid-tide zone of Guanabara Bay, Rio de Janeiro, Brazil and was artificially contaminated with crude oil at 14 g kg(-1). Bioremediation optimization was performed using an experimental design and statistical analysis of the following factors: supplementation with commercial biosurfactant Jeneil IBR 425 and commercial mineral NPK fertilizer. The response variable used was the biodegradation of the heavy oil fraction, HOF. The analysis of the studied factors and their interactions was executed using contour plots, Pareto diagram and ANOVA table. Experimental design results indicated that the supplementation with fertilizer at 100:25:25 C/N/P ratio and biosurfactant at 2 g kg(-1) yielded biodegradation of HOF at about 30% during 30 days of process. Some experiments were carried out using the experimental design results, yielding 65% of biodegradation of HOF and 100% of n- alkanes between C15 and C30 during 60 process days. Intrinsic biodegradation test was carried out, yielding 85% of biodegradation of n-alkanes between C15 and C30 during 30 days of process.

  19. The onset of fabric development in deep marine sediments

    Science.gov (United States)

    Maffione, Marco; Morris, Antony

    2017-09-01

    Post-depositional compaction is a key stage in the formation of sedimentary rocks that results in porosity reduction, grain realignment and the production of sedimentary fabrics. The progressive time-depth evolution of the onset of fabric development in deep marine sediments is poorly constrained due to the limited quantity and resolution of existing data. Here we present high-resolution anisotropy of magnetic susceptibility (AMS) results from clay-rich deep marine sediments recovered at International Ocean Discovery Program Site U1438 (Philippine Sea). AMS is a petrofabric tool sensitive to the preferred orientation of grains in rocks. Down-section variations of AMS parameters, density, porosity and the inclination of magnetic remanences demonstrate that fabrics develop in response to compaction and dewatering but also that they do not develop progressively with depth below the mudline. Instead, a horizontal foliation first forms at 83 mbsf once the sediment load reaches an effective stress threshold for the onset of compaction and is then continuously enhanced down to 113 mbsf, defining a 30 m-thick 'initial compaction window'. The magnetostratigraphic age model for IODP Site U1438 indicates a delay of 5.7 Ma in initial fabric formation following sediment deposition, with strongly defined fabrics then taking an additional 6.5 Ma to develop.

  20. 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

  1. 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

    ][mu]m, with a general increase over time and depth, and yet they shared 16S rRNA sequence identity of >98%. Comparison of the increase in biovolume and electric current density suggested high cellular growth efficiency. While the vertical expansion of filaments continued over time and reached 30[thinsp]mm, the electric......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...

  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

    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......][mu]m, with a general increase over time and depth, and yet they shared 16S rRNA sequence identity of >98%. Comparison of the increase in biovolume and electric current density suggested high cellular growth efficiency. While the vertical expansion of filaments continued over time and reached 30[thinsp]mm, the electric...

  3. Biodegradation of UV-filters in marine sediments.

    Science.gov (United States)

    Volpe, Angela; Pagano, Michele; Mascolo, Giuseppe; Grenni, Paola; Rossetti, Simona

    2017-01-01

    The degradation of two of the most frequently used UV-filters was investigated through microcosm studies. Marine sediments sampled from two sites in Italy (La Spezia harbour and Sarno river estuary, S1 and S2 respectively) were used to set up aerobic and anaerobic sets of reactors. The sediments were spiked with a methanol solution of 3-(4-methylbenzylidene)camphor (4-MBC) and 2-ethylhexyl 4-(dimethylamino)benzoate (EH-DPAB), at concentrations of either 25 or 50mgkg(-1) each. Methanol (6.3g/L) also served as an organic amendment and growth substrate for improving microbial activity. Monitoring of the biotic and abiotic degradation of the selected contaminants over 16months revealed that 4-MBC biodegradation was very slow and incomplete, whereas over 90% of EH-DPAB was degraded both in the aerobic and the anaerobic reactors by the natural microbial communities of both sediments. Repeated spikes of EH-DPAB were followed by complete decay, characterised by first-order kinetics. The calculated kinetic rate constants under aerobic and anaerobic conditions were similar. In reactors inoculated with the S1 sediment the degradation rate constants progressively increased after each spike, up to the value of 0.039d(-1). For the S2 sediment the rate constant was around 0.020d(-1) throughout the duration of the experiment. Mass spectrometry analysis of sediment extracts allowed detection of potential transformation products of EH-DPAB and 4-MBC. Moreover, the natural microbial community of the sediments was studied using the CAtalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) both in the initial sediments and after degradation under aerobic and anaerobic conditions.

  4. Effect of chemically contaminated marine sediment on naupliar production of the marine harpacticoid copepod, Tigriopus californicus

    Energy Technology Data Exchange (ETDEWEB)

    Misitano, D.A.; Schiewe, M.H. (National Oceanic and Atmospheric Administration, Seattle, WA (USA))

    1990-04-01

    There is a growing body of evidence indicating that chemically contaminated sediments in urban bays and estuaries pose a significant threat to the productivity of these important marine habitats. Particularly at risk are benthic species which live in direct contact with the sediment. However, nondemersal species are also at risk via the food chain and by direct contact with resuspended sediment particulates. There are substantial data on the lethal and sublethal effects of aqueous contaminants on a variety of aquatic species. In contrast, there is very limited information on the toxic effects of the generally water-insoluble sediment-associated contaminants. In the present communication the authors report a series of experiments in which the harpacticoid copepod, Tigriopus californicus, was exposed to sediments from urban and nonurban bays, and reproductive success was evaluated. This species was selected for study as it is widely distributed along the West Coast of North America, and as a group, copepods are an important component of the marine food chain. In addition, the relatively short reproductive life span of this species makes it particularly amenable for studies of reproductive success. Here, the authors report reduced and irregular naupliar production as a consequence of exposure to chemically contaminated sediments from urban waterways.

  5. The Role of Authigenic Volcanic Ash in Marine Sediment

    Science.gov (United States)

    Scudder, R.; McKinley, C. C.; Thomas, D. J.; Murray, R. W.

    2016-12-01

    Marine sediments are a fundamental archive of the history of weathering and erosion, biological productivity, volcanic activity, patterns of deep-water formation and circulation, and a multitude of other earth, ocean, and atmosphere processes. In particular, the record and consequences of volcanic eruptions have long fascinated humanity. Volcanic ash layers are often visually stunning, and can have thicknesses of 10s of cm or more. While the ash layer records are of great importance by themselves, we are missing a key piece of information-that of the very fined grained size fractions. Dispersed ash is the very fine grained-component that has either been mixed into the bulk sediment by bioturbation, or is deposited from subaqueous eruptions, erosion of terrestrial deposits, general input during time periods of elevated global volcanism, or other mechanisms, plays an important role in the marine sediment. The presence of dispersed ash in the marine record has previously been relatively over-looked as it is difficult to identify petrographically due to its commonly extremely fine grain size and/or alteration to authigenic clay. The dispersed ash, either altered or unaltered, is extremely difficult to differentiate from detrital/terrigenous/authigenic clay, as they are all "aluminosilicates". Here we apply a combined geochemical, isotopic, and statistical technique that enables us to resolve volcanic from detrital terrigenous inputs at DSDP/ODP/IODP sites from both the Brazil Margin and the Northwest Pacific Oceans. Incorporating the combined geochemical/statistical techniques with radiogenic isotope records allows us to address paleoceanographic questions in addition to studies of the effect of sediment fluxes on carbon cycling, the relationship between volcanic ash and biological productivity of the open ocean and nutrient availability for subseafloor microbial life.

  6. 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......-, Fe(III) oxides, or MnO2 are available as potential electron acceptors. In chemical experiments, FeS2 and FeS were oxidized by MnO2 but not with NO3- or amorphous Fe(III) oxide (Schippers and Jørgensen, 2001). Here we also show that in experiments with anoxic sediment slurries, a dissolution of tracer......-marked (FeS2)-Fe-55 occurred with MnO2 but not with NO3- or amorphous Fe(III) oxide as electron acceptor. To study a thermodynamically possible anaerobic microbial FeS, and FeS oxidation with NO3- or amorphous Fe(III) oxide as electron acceptor, more than 300 assays were inoculated with material from several...

  7. Petroleum biodegradation studied in sediment-flow-through systems simulating natural oil seepage in marine sediments

    Science.gov (United States)

    Mishra, Sonakshi; Wefers, Peggy; Steeb, Philip; Schmidt, Mark; Treude, Tina

    2014-05-01

    The natural biodegradation of hydrocarbons depends on several environmental factors like nutrients, salinity, temperature, pressure, redox-conditions and composition of crude oil. Petroleum migrating from depth into marine surface sediments at natural seep sites could be subjected to a sequence of different kind of microbial processes which is controlled by a strong redox gradient within a thin sediment segment. Most studies on microbial degradation of petroleum have focused either only on selected hydrocarbon fractions or on cultured microbes. This study, however, attempts to investigate the natural microbial response of marine sediments to crude oil seepage with detailed analysis of sediment and porewater geochemistry, hydrocarbon degradation products, microbial activity, and microbial genetics. A sediment-oil-flow-through-system was established where crude oil migrated through the bottom of (approximately 30 cm long) intact marine sediment cores simulating a natural seepage scenario. Electron acceptor-rich oxic seawater was provided at the top of the core and anoxic conditions were established at the bottom of the cores. The intact sediment cores had been sampled from the Caspian Sea (near Baku) and the North Alex Mud Volcano in the Mediterranean Sea. The Caspian Sea and the North Alex Mud Volcano are both sites with active transport of hydrocarbons from depth by mud volcano activity. The geochemical changes in the sediment cores during oil seepage were monitored by using microelectrodes and porewater analyses. The geochemical analysis was later followed by hydrocarbon and molecular analyses at the end of the experiment by slicing the cores. First results based on the biogeochemistry of the sediment cores and hydrocarbon analyses are presented here. Porewater profiles of hydrogen sulfide and sulfate during the experimental runs gave first indications of microbial response and sulfate reduction due to the addition of crude oil. The core from North Alex Mud

  8. 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 (marine environments harbour highly diverse actinobacterial communities, many of which appear to be novel, uncultured species.

  9. 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.

  10. An integrated approach to the toxicity assessment of Irish marine sediments: validation of established marine bioassays for the monitoring of Irish marine sediments.

    Science.gov (United States)

    Macken, Ailbhe; Giltrap, Michelle; Foley, Barry; McGovern, Evin; McHugh, Brendan; Davoren, Maria

    2008-10-01

    This paper describes the ecotoxicological evaluation of marine sediments from three sites around Ireland representative of a range of contaminant burdens. A comprehensive assessment of potential sediment toxicity requires the consideration of multiple exposure phases. In addition to the evaluation of multi-exposure phases the use of a battery of multi-trophic test species has been advocated by a number of researchers as testing of single or few organisms may not detect toxicants with a specific mode of action. The Microtox solid phase test (SPT) and the 10-d acute amphipod test with Corophium volutator were used to assess whole sediment toxicity. Porewater and elutriates were assessed with the Microtox acute test, the marine prasinophyte Tetraselmis suecica, and the marine copepod Tisbe battagliai. Solvent extracts were assayed with the Microtox and T. battagliai acute tests. Alexandra Basin was identified as the most toxic site according to all tests, except the Microtox SPT which identified the Dunmore East site as being more toxic. However, it was not possible to correlate the observed ecotoxicological effects with a specific and/or class of contaminants based on sediment chemistry alone. Therefore porewaters found to elicit significant toxicity (Dunmore East and Alexandra Basin) with the test battery were selected for further TIE assessment with T. battalgiai and the Microtox system. The results of this study have important implications for risk assessment in estuarine and coastal waters in Ireland, where, at present the monitoring of sediment and water quality is predominantly reliant on chemical analysis alone.

  11. Geochemical association of plutonium in marine sediments from Palomares (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Anton, M.P. [Dept. de Geoquimica e Impacto Ambiental, CIEMAT, Madrid (Spain); Gasco, C. [Dept. de Geoquimica e Impacto Ambiental, CIEMAT, Madrid (Spain); Sanchez-Cabeza, J.A. [Dept. de Fisica, Univ. Autonoma de Barcelona (Spain); Pujol, L. [Dept. de Fisica, Univ. Autonoma de Barcelona (Spain)

    1994-12-31

    The geochemical association of plutonium in sediments from the marine ecosystem of Palomares has been studied. A sequential leaching technique using selective extractants has been employed to determine the percentages of Pu in the following forms: (a) readily available, (b) exchangeable and adsorbed to specific sites, (c) associated with organic matter, (d) sesquioxides, (e) residual. Plutonium was found to be associated mainly with phases (c), (d) and (e), and therefore, appears to be relatively immobile and not readily available to bottom feeding biota. The effect of different source terms on Pu distribution is also discussed. (orig.)

  12. 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.

  13. 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.

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

    Science.gov (United States)

    Kiseleva, Larisa; Briliute, Justina; Khilyas, Irina V.; Simpson, David J. W.; Fedorovich, Viacheslav; Cohen, M.; Goryanin, Igor

    2015-01-01

    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. PMID:26504814

  15. JEDI Marine and Hydrokinetic Model: User Reference Guide

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, M.; Previsic, M.

    2011-04-01

    The Jobs and Economic Development Impact Model (JEDI) for Marine and Hydrokinetics (MHK) is a user-friendly spreadsheet-based tool designed to demonstrate the economic impacts associated with developing and operating MHK power systems in the United States. The JEDI MHK User Reference Guide was developed to assist users in using and understanding the model. This guide provides information on the model's underlying methodology, as well as the sources and parameters used to develop the cost data utilized in the model. This guide also provides basic instruction on model add-in features, operation of the model, and a discussion of how the results should be interpreted.

  16. Potential incursion of marine sediment inland in Northwest England

    Energy Technology Data Exchange (ETDEWEB)

    Huntley, D.A.; Dyer, K.R.; Cavrot, D. [Plymouth Univ (United Kingdom). Inst. of Marine Studies; Tooley, M.J.; Zong, Y. [Durham Univ (United Kingdom). Environmental Research Centre; Haslam, I.K.; Green, N.; Wilkins, B.T.

    1996-07-01

    An area of fine sediment off the Cumbrian coast acts as a reservoir for many of the radionuclides discharged into the Irish Sea from Sellafield. A collaborative project has been carried out to evaluate the origin of any marine sediment that could come ashore during a single storm event, to identify areas of the coast between Morecambe Bay and the Solway that could be at risk from flooding and to make an assessment of the doses that might be received as a result of such flooding. The assessment was based on realistic information whenever possible; in other cases, cautious assumptions were made. Any sediment transported inland would have come from the nearshore zone rather than directly from the offshore area. Although parts of the coast are currently at risk of flooding during severe storms, the doses that would be received by those engaged in clean-up operations and by residents would be a fraction of the limit recommended by ICRP for members of the public. (author).

  17. 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.

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

    Science.gov (United States)

    Schauer, Regina; Risgaard-Petersen, Nils; Kjeldsen, Kasper U; Tataru Bjerg, Jesper J; B Jørgensen, Bo; Schramm, Andreas; Nielsen, Lars Peter

    2014-06-01

    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 mm of the sediment, and after 21 days the filament density peaked with a total length of 2 km cm(-2). Cells elongated and divided at all depths with doubling times over the first 10 days of 98%. Comparison of the increase in biovolume and electric current density suggested high cellular growth efficiency. While the vertical expansion of filaments continued over time and reached 30 mm, the electric 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 to establish and exploit the spatially separated half-reactions of sulphide oxidation and oxygen consumption.

  19. A method of measurement of (239)Pu, (240)Pu, (241)Pu in high U content marine sediments by sector field ICP-MS and its application to Fukushima sediment samples.

    Science.gov (United States)

    Bu, Wenting; Zheng, Jian; Guo, Qiuju; Aono, Tatsuo; Tazoe, Hirofumi; Tagami, Keiko; Uchida, Shigeo; Yamada, Masatoshi

    2014-01-01

    An accurate and precise analytical method is highly needed for the determination of Pu isotopes in marine sediments for the long-term marine environment monitoring that is being done since the Fukushima Dai-ichi Nuclear Power Plant accident. The elimination of uranium from the sediment samples needs to be carefully checked. We established an analytical method based on anion-exchange chromatography and SF-ICP-MS in this work. A uranium decontamination factor of 2 × 10(6) was achieved, and the U concentrations in the final sample solutions were typically below 4 pg mL(-1), thus no extra correction of (238)U interferences from the Pu spectra was needed. The method was suitable for the analysis of (241)Pu in marine sediments using large sample amounts (>10 g). We validated the method by measuring marine sediment reference materials and our results agreed well with the certified and the literature values. Surface sediments and one sediment core sample collected after the nuclear accident were analyzed. The characterization of (241)Pu/(239)Pu atom ratios in the surface sediments and the vertical distribution of Pu isotopes showed that there was no detectable Pu contamination from the nuclear accident in the marine sediments collected 30 km off the plant site.

  20. 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

  1. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Targeted search for actinomycetes from near-shore and deep-sea marine sediments

    OpenAIRE

    Prieto-Davó, Alejandra; Villarreal-Gómez, Luis Jesús; Forschner-Dancause, Stephanie; Bull, Alan T.; Stach, James E. M.; David C. Smith; Rowley, Dave C.; Jensen, Paul R.

    2013-01-01

    Sediment samples collected off the coast of San Diego were analyzed for actinomycete diversity using culture independent techniques. Eight new operational taxonomic units (OTUs) in the Streptomycetaceae were identified as well as new diversity within previously cultured marine OTUs. Sequences belonging to the marine actinomycete genus Salinispora were also detected, despite the fact that this genus has only been reported from more tropical environments. Independent analyses of marine sediment...

  3. Capping of contaminated marine sediments : Redox reactions and trace metal mobility

    OpenAIRE

    Eide-Fredriksen, Jannicke

    2007-01-01

    The risk associated with exposure to contaminants, has drawn attention to the fate and transport of contaminants in marine sediments. Remediation of contaminated marine sediment has been necessary at several locations to reduce the risk of exposure. Capping is a widely used remediation strategy that aims to isolate the contaminants from the surrounding environment. Toxic trace metals are often found co-precipitated with iron sulphides in sediment. Interactions between oxic minerals in ca...

  4. Sorption kinetics of TNT and RDX in anaerobic freshwater and marine sediments: Batch studies.

    Science.gov (United States)

    Ariyarathna, Thivanka; Vlahos, Penny; Tobias, Craig; Smith, Richard

    2016-01-01

    Examination of the partitioning of explosives onto sediment in marine environments is critical to predict the toxicological impacts of worldwide explosive-contaminated sites adjacent to estuaries, wetlands, and the coastal ocean. Marine sediments have been identified as sites of enhanced munitions removal, yet most studies addressing these interactions focus on soils and freshwater sediments. The present study measured the kinetics of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) sorption onto 2 marine sediments of varying grain sizes (silt vs sand) and organic carbon (OC) content. Abiotic sediment sorption tests were performed at 23 °C, 15 °C, and 4 °C by spiking TNT and RDX solutions directly into anaerobic sediment slurries. Marine sediments showed significantly higher compound uptake rates (0.30-0.80 h(-1) ) than freshwater silt (0.0046-0.0065 h(-1) ) for both compounds, probably because of lower compound solubilities and a higher pH in marine systems. Equilibrium partition constants are on the same order of magnitude for marine silt (1.1-2.0 L kg(-1) sediment) and freshwater silt (1.4-3.1 L kg(-1) sediment) but lower for marine sand (0.72-0.92 L kg(-1) sediment). Total organic carbon content in marine sediments varied linearly with equilibrium partition constants for TNT and was moderately linear for RDX. Uptake rates and equilibrium constants of explosives are inversely correlated to temperature regardless of sediment type because of kinetic barriers associated with low temperatures. © 2015 SETAC.

  5. 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.

  6. Properties of bricks produced from Greenlandic marine sediments

    DEFF Research Database (Denmark)

    Bertelsen, Ida Maria Gieysztor; Belmonte, Louise Josefine; Chen, Wan

    2015-01-01

    This study investigated the possibility of a local brick production from fine grained marine sediments (MS) near Sisimiut, Greenland. The assessment is based on the physical and mechanical properties of clay bricks concerning the resistance to the harsh, Arctic weather conditions, together...... with an identification of a suitable production method. Samples of MS were collected near Sisimiut, Greenland, and tested with respect to the geological properties, which revealed a fine grained, low plasticity silty clay with evenly distributed grain sizes. By a screening of the mineralogy of MS by X-ray diffraction......, the major mineral phases were seen to be dominated by quarts and feldspar. Chemical investigations of MS showed low contents of both sulphur and carbon, whereas an unexpectedly high content of chlorine was found. A laboratory-scale study was made on fired brick pellets (d ∼20 mm, h ∼ 3 mm), and of fired...

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

    DEFF Research Database (Denmark)

    Thar, Roland Matthias; Kühl, Michael

    2002-01-01

    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......, 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......, forming a cohesive whitish veil at the oxic-anoxic interface. Bacteria attached to the veil kept rotating and adapted their stalk lengths dynamically to changing oxygen concentrations. The joint action of rotating bacteria on the veil induced a homogeneous water flow from the oxic water region toward...

  8. Environmental Characteristics of Polybrominated Diphenyl Ethers in Marine System, with Emphasis on Marine Organisms and Sediments

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2016-01-01

    Full Text Available Polybrominated diphenyl ethers (PBDEs, due to their widespread usage as flame retardants and their lipophilicity and persistence, have become ubiquitous in the environment. It is urgent to understand the environmental characteristics of PBDEs in marine system, but they have attracted little attention. We summarize the available data and analyze the regional distributions, controlling factors, and congener patterns of PBDEs in marine and associated environmental matrixes worldwide. Based on meta-analysis, after separating the estuarial sites from the marine sites, ignoring the extraordinary sample sites such as those located just near the point source, the PBDE concentration levels are still in the same order of magnitude from global scale. Despite Principal Component Analysis, the congener patterns of sediments are predominant with the heavy brominated congeners (BDE-209 contributing over 75% to the total load while the biota abound with the light ones (BDE-47, BDE-99, and BDE-100 taking about 80%. The ratio between BDE-99 and BDE-100 for the lower trophic-level species often turns to be greater than 1, while for those higher species the ratio may be below 1, and some species feed mainly on the crustaceans and zooplankton seems to have a higher ratio value. The data of the PBDEs in marine system are currently limited; thus, data gaps are identified as well.

  9. 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.

  10. Energetic constraints on life in deep marine sediments

    Science.gov (United States)

    Amend, J.; LaRowe, D.

    2013-12-01

    Microorganisms are abundant in deep-sea sediments, but what percentage of cells is active, how fast do they grow, and what factors control their diversity and population size? Geochemical modelling of redox reaction energetics can help in answering these questions. Calculations of Gibbs energies reveal which reactions are thermodynamically possible, but they also highlight which geochemical variables (e.g., temperature, pressure, pH, composition) may control microbial activity and how the amount and type of biomass are affected by energy limitations. We will discuss recent results from sediment cores collected at the Peru Margin (active continental shelf with high primary productivity and significant organic matter accumulation), the South Pacific Gyre (ultra-slow sedimentation rate and low organic carbon content), and the Juan de Fuca Ridge flank (high rate of sedimentation influenced by hydrothermal circulation). However, this approach to evaluating bioenergetic potential and predicting microbial activity can be applied to any environment where the geochemistry is well characterized, even if microbiology data have not been collected. When Gibbs energies are calculated on a basis of per mole of electrons transferred (as is commonly done), aerobic oxidation of hydrogen and organic matter in South Pacific Gyre sediments is the most exergonic. Based on this, one might posit that the fastest catabolic rates and the largest biomass would be found there. However, cell counts at Juan de Fuca and the Peru Margin are several orders of magnitude higher. When recast as energy densities (in J per cm3 of sediment), we observe far more energy available in sediments at Juan de Fuca and the Peru Margin than at those in the South Pacific Gyre. We also note that the identity of the most exergonic reaction changes with depth, suggesting corresponding changes in the microbial community structure. The thermodynamic approach used here for energy supply can also be used for energy

  11. Environmental Guidance Program Reference Book: Marine Protection, Research, and Sanctuaries Act and Marine Mammal Protection Act. Revision 3

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-31

    Two laws governing activities in the marine environment are considered in this Reference Book. The Marine Protection, Research, and Sanctuaries Act (MPRSA, P.L. 92-532) regulates ocean dumping of waste, provides for a research program on ocean dumping, and provides for the designation and regulation of marine sanctuaries. The Marine Mammal Protection Act (MMPA, P.L. 92-522) establishes a federal program to protect and manage marine mammals. The Fishery Conservation and Management Act (FCMA, P.L. 94-265) establishes a program to regulate marine fisheries resources and commercial marine fishermen. Because the Department of Energy (DOE) is not engaged in any activities that could be classified as fishing under FCMA, this Act and its regulations have no implications for the DOE; therefore, no further consideration of this Act is given within this Reference Book. The requirements of the MPRSA and the MMPA are discussed in terms of their implications for the DOE.

  12. 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.

  13. Description of Specimens in the Marine Mammal Osteology Reference Collection

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NMFS Alaska Fisheries Science Center National Marine Mammal Laboratory (NMML) Marine Mammal Osteology Collection consists of approximately 2500 specimens (skulls...

  14. Sulfur-Oxidizing Bacteria Mediate Microbial Community Succession and Element Cycling in Launched Marine Sediment

    OpenAIRE

    Ihara, Hideyuki; Hori, Tomoyuki; Aoyagi, Tomo; Mitsuru TAKASAKI; Katayama, Yoko

    2017-01-01

    A large amount of marine sediment was launched on land by the Great East Japan earthquake. Here, we employed both on-site and laboratory studies on the launched marine sediment to investigate the succession of microbial communities and its effects on geochemical properties of the sediment. Twenty-two-month on-site survey showed that microbial communities at the uppermost layer (0–2 mm depth) of the sediment changed significantly with time, whereas those at the deeper layer (20–40 mm depth) re...

  15. Genomes of two new ammonia-oxidizing archaea enriched from deep marine sediments.

    Directory of Open Access Journals (Sweden)

    Soo-Je Park

    Full Text Available Ammonia-oxidizing archaea (AOA are ubiquitous and abundant and contribute significantly to the carbon and nitrogen cycles in the ocean. In this study, we assembled AOA draft genomes from two deep marine sediments from Donghae, South Korea, and Svalbard, Arctic region, by sequencing the enriched metagenomes. Three major microorganism clusters belonging to Thaumarchaeota, Epsilonproteobacteria, and Gammaproteobacteria were deduced from their 16S rRNA genes, GC contents, and oligonucleotide frequencies. Three archaeal genomes were identified, two of which were distinct and were designated Ca. "Nitrosopumilus koreensis" AR1 and "Nitrosopumilus sediminis" AR2. AR1 and AR2 exhibited average nucleotide identities of 85.2% and 79.5% to N. maritimus, respectively. The AR1 and AR2 genomes contained genes pertaining to energy metabolism and carbon fixation as conserved in other AOA, but, conversely, had fewer heme-containing proteins and more copper-containing proteins than other AOA. Most of the distinctive AR1 and AR2 genes were located in genomic islands (GIs that were not present in other AOA genomes or in a reference water-column metagenome from the Sargasso Sea. A putative gene cluster involved in urea utilization was found in the AR2 genome, but not the AR1 genome, suggesting niche specialization in marine AOA. Co-cultured bacterial genome analysis suggested that bacterial sulfur and nitrogen metabolism could be involved in interactions with AOA. Our results provide fundamental information concerning the metabolic potential of deep marine sedimentary AOA.

  16. Genomes of two new ammonia-oxidizing archaea enriched from deep marine sediments.

    Science.gov (United States)

    Park, Soo-Je; Ghai, Rohit; Martín-Cuadrado, Ana-Belén; Rodríguez-Valera, Francisco; Chung, Won-Hyong; Kwon, KaeKyoung; Lee, Jung-Hyun; Madsen, Eugene L; Rhee, Sung-Keun

    2014-01-01

    Ammonia-oxidizing archaea (AOA) are ubiquitous and abundant and contribute significantly to the carbon and nitrogen cycles in the ocean. In this study, we assembled AOA draft genomes from two deep marine sediments from Donghae, South Korea, and Svalbard, Arctic region, by sequencing the enriched metagenomes. Three major microorganism clusters belonging to Thaumarchaeota, Epsilonproteobacteria, and Gammaproteobacteria were deduced from their 16S rRNA genes, GC contents, and oligonucleotide frequencies. Three archaeal genomes were identified, two of which were distinct and were designated Ca. "Nitrosopumilus koreensis" AR1 and "Nitrosopumilus sediminis" AR2. AR1 and AR2 exhibited average nucleotide identities of 85.2% and 79.5% to N. maritimus, respectively. The AR1 and AR2 genomes contained genes pertaining to energy metabolism and carbon fixation as conserved in other AOA, but, conversely, had fewer heme-containing proteins and more copper-containing proteins than other AOA. Most of the distinctive AR1 and AR2 genes were located in genomic islands (GIs) that were not present in other AOA genomes or in a reference water-column metagenome from the Sargasso Sea. A putative gene cluster involved in urea utilization was found in the AR2 genome, but not the AR1 genome, suggesting niche specialization in marine AOA. Co-cultured bacterial genome analysis suggested that bacterial sulfur and nitrogen metabolism could be involved in interactions with AOA. Our results provide fundamental information concerning the metabolic potential of deep marine sedimentary AOA.

  17. Foraminiferal constituent in marine sediments - A parameter in some coastal engineering problems

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    Foraminifera, among other microorganisms, form a major constituent of marine sediments and their composition is directly related to the nature of the substrate in which they are entombed. Past and the present data indicate that the size, test...

  18. Marine and terrigenous lipids in southeast atlantic sediments (leg 175) as paleoenvironmental indicators: initial results

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Schefuss, E.; Versteegh, G.J.M.; Jansen, J.H.F.

    2001-01-01

    Lipid compositions of sediments recovered during Ocean Drilling Program Leg 175 in the eastern South Atlantic reflect a variety of oceanographic and climatological environments. Most of the identified lipids can be ascribed to marine sources, notably haptophytes, eustigmatophytes, dinoflagellates, a

  19. 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; Mohamed Kamari, Halimah; Chee Kong, Yap; Suhaimi Hamzah, Mohd; Suhaimi Elias, Md

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Comportement des sédiments marins carbonatés Behaviour of Marine Carbonate Sediments

    Directory of Open Access Journals (Sweden)

    Nauroy J. F.

    2006-11-01

    Full Text Available Les sédiments carbonatés recouvrent les fonds marins de nombreuses zones d'activités pétrolières actuelles. La méconnaissance des caractéristiques mécaniques de ces sols explique en partie les difficultés rencontrées pour l'implantation de structures marines. Un important programme d'essais réalisés sur divers sédiments carbonatés a été effectué afin de préciser : - la définition d'une méthodologie d'identification de ces sédiments ; - l'influence de leurs caractéristiques physiques sur leur comportement mécanique. Le comportement des sédiments carbonatés, soumis à des sollicitations cycliques simulant l'action de la houle sur les fondations d'ouvrages en mer, a été longuement étudié à l'appareil triaxial et sur un modèle réduit de similitude de fondation de structure à embase poids en utilisant la technique de centrifugation. Les essais réalisés confirment l'importance du seuil caractéristique comme limite fondamentale dans l'étude des sables carbonatés sous chargement cyclique. Carbonate sediments cover the seabed of many areas where petroleum activities are now taking place. Incomplete understanding of the mechanical properties of such formations partly explains the difficulties encountered in installing offshore structures. An extensive testing program involving different carbonate sediments has been carried out for two reasons : (1 to define a methodology for identifying these sediments, and (2 to determine the influence of their physical properties on their mechanical behavior. The behavior of carbonate sediments subjected to cyclic loading, simulating wave action on offshore structures, foundations, has been intensively investigated, using a triaxial devise and with a scale model simulating the foundation of a gravity structure using the centrifuging technique. These tests confirm the importance of the characteristic threshold as the fundamental limit in investigating carbonate sands under cyclic

  1. Thraustochytrids (fungoid protist: an unexplored component of marine sediment microbiota

    Directory of Open Access Journals (Sweden)

    Lucia Bongiorni

    2004-04-01

    Full Text Available Thraustochytrids are poorly known fungoid protists able to decompose refractory organic substrates such as cellulose. These microorganisms probably play an important role in the microbial loop of marine sediments. This paper reports a study conducted on thraustochytrids dwelling in a sandy shore of the Eastern Ligurian Sea. One hundred twenty eight samples (1 ml each were collected, to examine Thraustochytrid spatial distribution, following a nested ANOVA design, that incorporated 3 successively smaller spatial scales (different sampling units ranging from metres to centimetres. Samples were examined by a direct, improved, fluorochrome-count method also suitable for ciliates. Sampling was repeated 4 times in autumn-winter. The average abundance of thraustochytrids (±SE was 42.3±2.9 ml-1, with no significant decrease over time. The densities of thraustochytrids and ciliates varied significantly but at different spatial scales: the former between squares (3.3 x 3.3 m, and the latter between subplots (0.01 x 0.01m, indicating their tendency to form patches at different spatial scales. A significant correlation was found between the densities of the two protists, suggesting some interaction between them could occur. The thraustochytrid abundance supports the idea that these protists play a an important role in carbon cycling of Mediterranean sandy shores.

  2. 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.

  3. Adsorption-desorption of oxytetracycline on marine sediments: Kinetics and influencing factors.

    Science.gov (United States)

    Li, Jia; Zhang, Hua

    2016-12-01

    To reveal the kinetics and mechanisms of antibiotic adsorption/desorption processes, batch and stirred flow chamber (SFC) experiments were carried out with oxytetracycline (OTC) on two marine sediments. The OTC adsorption capacities of the marine sediments were relatively weak and related to their organic carbon (OC) and contents of fine particles. Sorption isotherms of OTC on marine sediment can be well described by both the Langmuir and Freundlich models. Langmuir adsorption maxima (qmax) and Freundlich distribution coefficients (Kf) increased with the decrease of salinity and pH, which indicated the importance of variable charged sites on sediment surfaces. A second order kinetic model successfully described adsorption and desorption kinetics of OTC and well reproduced the concentration change during stop-flow. The adsorption kinetic rates (ka) for OTC under different experimental conditions ranged from 2.00 × 10(-4) to 1.97 × 10(-3) L (mg min)(-1). Results of SFC experiments indicated that diffusive mass transfer was the dominant mechanism of the time-dependent adsorption of OTC and its release from marine sediment was mildly hysteretic. The high desorption percentage (43-75% for LZB and 58-75% for BHB) implied that binding strength of OTC on two marine sediments was weak. In conclusion, marine sediment characteristics and environmental factors such as salinity, pH, and flow rate are critical factors determine extent of OTC sorption on marine sediment and need to be incorporated in modeling fate and transport of OTC in marine environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. 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....

  5. Coupled LBM-DEM Three-phase Simulation on Gas Flux Seeping from Marine Sediment

    Science.gov (United States)

    Kano, Y.; Sato, T.

    2014-12-01

    One of the main issues of the geological storage of CO2 under the seabed is a risk of CO2 leakage. Once CO2seeps into the ocean, it rises in water column dissolving into seawater, which results in the acidification of seawater and/or returning to the air. Its behaviour significantly depends on flow rate and bubble size (Kano et al., 2009; Dewar et al., 2013). As for porous media, bubble size is generally predicted through simple force balance based on flow rate, surface tension and channel size which is estimated by porosity and grain size. However, in shallow marine sediments, grains could be mobilised and displaced by buoyant gas flow, which causes distinctive phenomena such as blow-out or formation of gas flow conduit. As a result, effective gas flux into seawater can be intermissive, and/or concentrated in narrow area (QICS, 2012; Kawada, 2013). Bubble size is also affected by these phenomena. To predict effective gas flux and bubble size into seawater, three-phase behaviour of gas-water-sediment grains should be revealed. In this presentation, we will report the results of gas-liquid-solid three-phase simulations and their comparisons with experimental and observation data. Size of solid particles is based on grain size composing marine sediments at some CCS project sites. Fluid-particle interactions are solved using the lattice Boltzmann method (LBM), while the particle-particle interactions are treated by coupling with the Discrete Element method (DEM). References: Dewar, M., Wei, W., McNeil, D., Chen, B., 2013. Small-scale modelling of the physiochemical impacts of CO2leaked from sub-seabed reservoirs or pipelines within the North Sea and surrounding waters. Marine Pollution Bulletin 73(2), 504-515. Kano, Y., Sato, T., Kita, J., Hirabayashi, S., Tabeta, S., 2009. Model prediction on the rise of pCO2 in uniform flows by leakage of CO2purposefully stored under the seabed. Int. J. Greenhouse Gas Control, Vol. 3(5), 617-625. Kawada, R. 2014. A study on the

  6. Evaluation of the potential for using Greenlandic marine sediments for brick production

    DEFF Research Database (Denmark)

    Belmonte, Louise Josefine; Bertelsen, Ida Maria Gieysztor

    2016-01-01

    Fine grained marine sediments from near the Greenlandic towns of Ilulissat, Kangerlussuaq and Sisimiut were assessed as raw materials for local production of building bricks. The assessment included both analysis of the sediment characteristics and physical properties of miniature test brick...

  7. Ecotoxicological Response of Marine Organisms to Inorganic and Organic Sediment Amendments in Laboratory Exposures

    Science.gov (United States)

    2011-08-15

    adsorption, and transformation. In marine sediments, transition metals form relatively stable insoluble complexes with hydrogen sulfide (HS-) and carbonate...2008). While some experimental amendments have been added to sediments to sorb, degrade, transform or immobilize toxins and metals, others are added...reducing bacteria, promoting the precipitation of metals as sulfides , rendering the metals non-bioavailable. Regardless of the amendment composition

  8. 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...

  9. 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...

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

    Science.gov (United States)

    Tsabaris, C; Patiris, D L; Fillis-Tsirakis, E; Kapsimalis, V; Pilakouta, M; Pappa, F K; Vlastou, R

    2015-06-01

    The aim of the present work is the study of (137)Cs 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 (137)Cs 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, (137)Cs 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 (137)Cs in the sediment column. The proposed model estimates the temporal variation of (137)Cs activity concentration from 1987 (one year after the Chernobyl accident) till today (2014).

  11. Google Earth-Based Grand Tours of the World's Ocean Basins and Marine Sediments

    Science.gov (United States)

    St John, K. K.; De Paor, D. G.; Suranovic, B.; Robinson, C.; Firth, J. V.; Rand, C.

    2016-12-01

    The GEODE project has produced a collection of Google Earth-based marine geology teaching resources that offer grand tours of the world's ocean basins and marine sediments. We use a map of oceanic crustal ages from Müller et al (2008; doi:10.1029/2007GC001743), and a set of emergent COLLADA models of IODP drill core data as a basis for a Google Earth tour introducing students to the world's ocean basins. Most students are familiar with basic seafloor spreading patterns but teaching experience suggests that few students have an appreciation of the number of abandoned ocean basins on Earth. Students also lack a valid visualization of the west Pacific where the oldest crust forms an isolated triangular patch and the ocean floor becomes younger towards the subduction zones. Our tour links geographic locations to mechanical models of rifting, seafloor spreading, subduction, and transform faulting. Google Earth's built-in earthquake and volcano data are related to ocean floor patterns. Marine sediments are explored in a Google Earth tour that draws on exemplary IODP core samples of a range of sediment types (e.g., turbidites, diatom ooze). Information and links are used to connect location to sediment type. This tour compliments a physical core kit of core catcher sections that can be employed for classroom instruction (geode.net/marine-core-kit/). At a larger scale, we use data from IMLGS to explore the distribution of the marine sediments types in the modern global ocean. More than 2,500 sites are plotted with access to original data. Students are guided to compare modern "type sections" of primary marine sediment lithologies, as well as examine site transects to address questions of bathymetric setting, ocean circulation, chemistry (e.g., CCD), and bioproductivity as influences on modern seafloor sedimentation. KMZ files, student exercises, and tips for instructors are available at geode.net/exploring-marine-sediments-using-google-earth.

  12. Contrasting sediment records of marine submersion events related to wave exposure, Southwest France

    Science.gov (United States)

    Baumann, J.; Chaumillon, E.; Schneider, J.-L.; Jorissen, F.; Sauriau, P.-G.; Richard, P.; Bonnin, J.; Schmidt, S.

    2017-05-01

    Sediment records of two contrasting backshore coastal marshes, extremely vulnerable to recent and historical marine flooding events, located on the SW coast of France, have been investigated using a multiproxy approach. The studied marshes are 30 km apart and have been flooded by similar storm events (7 marine floods in the last 250 years). One is located in a wave-exposed coast but isolated from the sea by a sediment barrier, whereas the other is located in a sheltered estuarine environment and isolated from the sea by a dike. One core was collected in each marsh and information on grain-size, foraminifera, shell contents and stable carbon isotopes was obtained along with an age model using 210Pb, 137Cs and 14C. Core data combined with historical maps give evidence of a typical estuarine backfilling, part of the Holocene regressive parasequence, including an intertidal mudflat at the base and a backshore environment at the top. Despite the absence of grain size anomalies, marine flood-related sedimentation in the backshore area of both marshes is identified by a mixture of marine and terrestrial features, including marine fauna, vegetation debris and variation in the δ13C signature of the organic fraction. Very low sedimentation rates between flood events and/or bioturbation prevents the identification of individual episodic marine floods in the sediment succession. Comparison of the two sedimentary successions shows that the foraminifera deposited by marine submersions are of two different types. Foraminifera are monospecific and originate from the upper tidal mudflat in the sheltered marsh; whereas in the backshore marsh located in a wave-exposed environment, they show higher diversity and originate from both shallow and deeper water marine environments. This study shows that wave exposure can control the faunal content of marine flood sediment records in coastal marshes.

  13. NMR-based metabolomics for the environmental assessment of Kaohsiung Harbor sediments exemplified by a marine amphipod (Hyalella azteca).

    Science.gov (United States)

    Chiu, K H; Dong, C D; Chen, C F; Tsai, M L; Ju, Y R; Chen, T M; Chen, C W

    2017-03-03

    Inflow of wastewater from upstream causes a large flux of pollutants to enter Kaohsiung Harbor in Taiwan daily. To reveal the ecological risk posed by Kaohsiung Harbor sediments, an ecological metabolomic approach was employed to investigate environmental factors pertinent to the physiological regulation of the marine amphipod Hyalella azteca. The amphipods were exposed to sediments collected from different stream inlets of the Love River (LR), Canon River (CR), Jen-Gen River (JR), and Salt River (SR). Harbor entrance 1 (E1) was selected as a reference site. After 10-day exposure, metabolomic analysis of the Hyalella azteca revealed differences between two groups: {E1, LR, CR} and {JR, SR}. The metabolic pathways identified in the two groups of amphipods were significantly different. The results demonstrated that NMR-based metabolomics can be effectively used to characterize metabolic response related to sediment from polluted areas.

  14. 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

  15. 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

  16. Ecotoxicological evaluation of marine sediments using free and immobilized phytoplanktonic algae

    Directory of Open Access Journals (Sweden)

    E. Giacco

    2011-01-01

    Full Text Available Marine sediments play an important role in the accumulation-storage and/or release of contaminants in seawaters; sedimets bioassays provide for general information on pollutant bioavailability. This work points out the importance to utilize free and immobilised (Na-alginate marine algae for the ecotoxicological evaluation of metals (Cd, Zn, Cu as well as of elutriates and whole sediment samples collected in harbour sites. The bioassay was carried out with the marine microalga Tetraselmis suecica; algal growth inhibition was determined after 24 and 48 hours as percent growth in comparison to controls. After 24 hours a lower toxicity of metals for the immobilised algae than for free algae was observed; this trend decreased in time. Algae exposed to whole sediment ahowed a greater reduction of growth than algae exposed to the relative elutriate. This result emphasizes that the whole sediments seem to be suitable to detect the toxicity of such complex environmental matrix.

  17. 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.

  18. Foraminiferal indicators of high OC content in marine sediments; a question of OC source?

    Science.gov (United States)

    Lo Giudice Cappelli, Elena; Austin, William; Smith, Laura; Ward, Hannah; Clarke, Jess; Green, Jade; Smeaton, Craig

    2017-04-01

    West Shetland voes (sea inlets), on Scotland northern maritime periphery, represent a range of environmental and depositional settings in an area of coastal ocean which is characterised by a generally high organic carbon content in marine sediments. Possible sources of organic carbon are fish farms, as this region is experiencing a large expansion in marine aquaculture, and/or erosion of peatland. Twenty-one sites in six voes were sampled in August 2015 following an organic carbon gradient. The aims of this study are: 1) to establish the modern biogeography of benthic foraminifera in west Shetland voes, 2) to explore the use of these organisms as bio-indicators of high organic carbon content in marine sediments, and 3) to trace the source of organic carbon and its transportation between different habitats and pools (e.g.: terrestrial to marine; marine aquaculture to sediments). To achieve this, we paired together spatial variations in the composition of benthic foraminiferal assemblages (species abundance and diversity) with changes in the physical properties of marine sediments determined by carbon stable isotope measurements and loss on ignition analysis. Preliminary results show a positive relationship between high abundance of the agglutinated benthic foraminifera Eggerelloides scaber, high organic carbon content in the sediments and proximity to fish farms. Although aquaculture farming in these areas may be a contributing factor, radiocarbon dates demonstrate that organic enrichment in the sediments pre-dates the introduction of aquaculture, while carbon stable isotope measurements point to peat erosion as a more likely source of organic carbon in west Shetland voes. Therefore, peatland erosion is a significant source of organic carbon in marine sediments and may be an important contributor to the store of blue carbon in west Shetland voes and, more in general, in the coastal ocean.

  19. The rate of removal and the compositional changes of diesel in Antarctic marine sediment.

    Science.gov (United States)

    Woolfenden, E N M; Hince, G; Powell, S M; Stark, S C; Snape, I; Stark, J S; George, S C

    2011-12-01

    Diesels and lubricants used at research stations can persist in terrestrial and marine sediments for decades, but knowledge of their effects on the surrounding environments is limited. In a 5 year in situ investigation, marine sediment spiked with Special Antarctic Blend (SAB) diesel was placed on the seabed of O'Brien Bay near Casey Station, Antarctica and sampled after 5, 56, 65, 104 and 260 weeks. The rates and possible mechanisms of removal of the diesel from the marine sediments are presented here. The hydrocarbons within the spiked sediment were removed at an overall rate of 4.7mg total petroleum hydrocarbons kg(-1) sediment week(-1), or 245mgkg(-1)year(-1), although seasonal variation was evident. The concentration of total petroleum hydrocarbons fell markedly from 2020±340mgkg(-1) to 800±190mgkg(-1), but after 5 years the spiked sediment was still contaminated relative to natural organic matter (160±170mgkg(-1)). Specific compounds in SAB diesel preferentially decreased in concentration, but not as would be expected if biodegradation was the sole mechanism responsible. Naphthalene was removed more readily than n-alkanes, suggesting that aqueous dissolution played a major role in the reduction of SAB diesel. 1,3,5,7-Teramethyladamantane and 1,3-dimethyladamantane were the most recalcitrant isomers in the spiked marine sediment. Dissolution of aromatic compounds from marine sediment increases the availability of more soluble, aromatic compounds in the water column. This could increase the area of contamination and potentially broaden the region impacted by ecotoxicological effects from shallow sediment dwelling fauna, as noted during biodegradation, to shallow (<19m) water dwelling fauna.

  20. Dissolved and particulate carbohydrates in contrasting marine sediments

    Science.gov (United States)

    Burdige, D. J.; Skoog, A.; Gardner, K.

    2000-03-01

    Dissolved and particulate carbohydrates were examined in contrasting Chesapeake Bay (estuarine) and mid-Atlantic shelf/slope break (continental margin) sediments. Particulate carbohydrates (PCHOs) represented ˜5-9% of the total sediment particulate organic carbon (POC), and PCHO remineralization appeared to be a similar fraction of total sediment carbon oxidation (or C ox). When these results are compared with results from other coastal sediments and a pelagic turbidite, PCHO remineralization (as a percentage of C ox) did not vary by more than a factor of ˜2-3 over a 3-4 order of magnitude range in C ox values. The causes of this are not well understood, but may be related to specific effects associated with the remineralization of highly altered organic matter mixtures under aerobic conditions. Dissolved carbohydrates (DCHOs) in these sediment pore waters ranged from ˜30 to 400 μM, increased with depth in a manner similar to total DOC, and represented ˜10 to 55% of pore water DOC. In Chesapeake Bay sediments this percentage decreased with sediment depth, while in these continental margin sediments it was constant (upper 30 cm). Of the DCHOs in these pore waters ˜30 to 50% could be identified as individual aldoses (monomeric neutral sugars), and total aldose yields (individual aldoses as a percentage of total DOC) were higher in these continental margin sediment pore waters (>9%) than they were in the estuarine sediment pore waters (<5%). A comparison of DCHO and PCHO concentrations in these sediments indicates that their concentrations are uncoupled, and that pore water DCHO concentrations are primarily controlled by sediment remineralization processes. Pore water DCHOs appeared to be preferentially found in the high molecular weight (HMW) DOC pool, and likely occur as some of the initial HMW intermediates produced and consumed during sediment POC remineralization. These results also support past suggestions about the differing controls on carbon

  1. 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.

  2. 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.

  3. Anodes Stimulate Anaerobic Toluene Degradation via Sulfur Cycling in Marine Sediments.

    Science.gov (United States)

    Daghio, Matteo; Vaiopoulou, Eleni; Patil, Sunil A; Suárez-Suárez, Ana; Head, Ian M; Franzetti, Andrea; Rabaey, Korneel

    2015-10-23

    Hydrocarbons released during oil spills are persistent in marine sediments due to the absence of suitable electron acceptors below the oxic zone. Here, we investigated an alternative bioremediation strategy to remove toluene, a model monoaromatic hydrocarbon, using a bioanode. Bioelectrochemical reactors were inoculated with sediment collected from a hydrocarbon-contaminated marine site, and anodes were polarized at 0 mV and +300 mV (versus an Ag/AgCl [3 M KCl] reference electrode). The degradation of toluene was directly linked to current generation of up to 301 mA m(-2) and 431 mA m(-2) for the bioanodes polarized at 0 mV and +300 mV, respectively. Peak currents decreased over time even after periodic spiking with toluene. The monitoring of sulfate concentrations during bioelectrochemical experiments suggested that sulfur metabolism was involved in toluene degradation at bioanodes. 16S rRNA gene-based Illumina sequencing of the bulk anolyte and anode samples revealed enrichment with electrocatalytically active microorganisms, toluene degraders, and sulfate-reducing microorganisms. Quantitative PCR targeting the α-subunit of the dissimilatory sulfite reductase (encoded by dsrA) and the α-subunit of the benzylsuccinate synthase (encoded by bssA) confirmed these findings. In particular, members of the family Desulfobulbaceae were enriched concomitantly with current production and toluene degradation. Based on these observations, we propose two mechanisms for bioelectrochemical toluene degradation: (i) direct electron transfer to the anode and/or (ii) sulfide-mediated electron transfer. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  4. Potential Impacts of PCBs on Sediment Microbiomes in a Tropical Marine Environment

    Directory of Open Access Journals (Sweden)

    James S. Klaus

    2016-02-01

    Full Text Available Within the tropical marine study site of Guánica Bay, Puerto Rico, polychlorinated biphenyls (PCBs are subjected to coastal and oceanic currents coupled with marine microbial and geochemical processes. To evaluate these processes a hydrodynamic model was developed to simulate the transport of PCBs within nearshore and offshore marine areas of Guánica Bay. Material transport and circulation information from the model were matched with measurements from samples collected from within the bay. These samples, consisting of both intertidal and submerged sediments, were analyzed for physical characteristics (organic carbon, grain size, and mineralogy, microbial characteristics (target bacteria levels and microbial community analyses, presence of PCBs, and PCB-degrading enzymes. Results show that the bay geometry and bathymetry limit the mixing of the extremely high levels of PCBs observed in the eastern portion of the bay. Bay bottom sediments showed the highest levels of PCBs and these sediments were characterized by high organic carbon content and finer grain size. Detectable levels of PCBs were also observed within sediments found along the shore. Microbes from the bay bottom sediments showed a greater relative abundance of microbes from the Chloroflexi, phylum with close phylogenetic associations with known anaerobic PCB-degrading organisms. Based on quantitative PCR measurement of the biphenyl dioxygenase gene, the intertidal sediments showed the greatest potential for aerobic PCB degradation. These results elucidate particular mechanisms of PCB’s fate and transport in coastal, tropical marine environments.

  5. The microbial nitrogen cycling potential is impacted by polyaromatic hydrocarbon pollution of marine sediments.

    Science.gov (United States)

    Scott, Nicole M; Hess, Matthias; Bouskill, Nick J; Mason, Olivia U; Jansson, Janet K; Gilbert, Jack A

    2014-01-01

    During 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 within the surface layer of marine sediments causing 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 (DWH) 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.

  6. Levelized Cost of Energy Analysis of Marine and Hydrokinetic Reference Models: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jenne, D. S.; Yu, Y. H.; Neary, V.

    2015-04-24

    In 2010 the U.S. Department of Energy initiated the development of six marine energy converter reference models. The reference models are point designs of well-known marine energy converters. Each device was designed to operate in a specific marine resource, instead of a generic device that can be deployed at any location. This method allows each device to be used as a benchmark for future reference model to benchmark future devices. The six designs consist of three current energy converters and three wave energy converters. The reference model project has generated both technical and economic data sets that are available in the public domain. The methodology to calculate the levelized cost of energy for the reference model project and an overall comparison of the cost of energy from these six reference-model designs are presented in this paper.

  7. Transformation of marine sediment to paddy soil: Primary marine, lacustrine, and land plant lipids

    Science.gov (United States)

    Mueller-Niggemann, Cornelia; Cao, Zhihong; Schwark, Lorenz

    2010-05-01

    More than fifty percent of the world's population feeds on rice. The continuous population increase and urban sprawl leads to an ever-increasing demand for new rice cultivation area, in particular China. For centuries suitable coastal areas in China have been exploited for land reclamation, i.e. conversion of coastal marine and lacustrine marshlands into rice paddy fields. Flooded rice paddies are considered one of the major biogenic sources of methane into the atmospheric. Methane is thought to be about 30 times more efficient as greenhouse gas, when compared to carbon dioxide. Overall, rice fields are assumed to contribute app. 10-25% to global CH4 production. It is thus paramount importance to study the effects of increasing rice cultivation and land reclamation in China. For global carbon cycle investigation, it is crucial whether paddy soils, due to their large extent and higher carbon turnover, serve as carbon (CO2) sinks or sources. Here we present results from a chronosequence study of paddy soils with different and well known starting dates of cultivation, in the Zhejiang province (Yangtze River delta) by land reclamation through the building of protective dikes over the past 2000 years. Two end members of natural sediments subjected to land reclamation, a marine tidal mudflat in the Yangtze delta and a coastal lake, represent the substrate on which the paddy soil evolution started. Dike systems were constructed 2000, 1000, 700, 300, 100, and 50 years before present. We are thus able to follow the evolution of rice paddy soils developed on marine sediments using eight well defined tie-points. This chronosequence is then used for assessing the relative proportion of primary marine or lacustrine organic matter preserved in present day soils and to identify the amount and composition of organic matter added since cultivation started. Paddy soil management introduces rice plants debris and exudates as well as rice-associated microbial biomass (covered in a

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

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.

    The inhibitory effects of the organics from the sediment along the east coast of India on acetylcholinesterase (AChE) in-vitro were evaluated. Sediment samples collected from the surface layers at various depths were extracted. Each of the extracts...

  9. 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...

  10. 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.

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

    Science.gov (United States)

    Hafidz, B. Y.; Asnor, A. S.; Terence, R. C.; Mohamed, C. A. R.

    2014-02-01

    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 228Th/232Th model. The results suggest the 230Th and 232Th might be originated from terrestrial sedimentary rock while 228Th originated by authigenic origin. High ratio value of 230Th/232Th detected at the top surface sediment indicates the increasing of 230Th 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 228Th/232Th 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.

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

    DEFF Research Database (Denmark)

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

    oxidation of sulphide centimeters down in marine sediment to the reduction of oxygen at the very surface1 . This electric coupling of spatially separated redox half-reactions seems to be mediated by centimeter long filamentous Desulfubulbus affiliated bacteria with morphological and ultra......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......-structural properties suggesting that they are living electric micro cables. The mode of action of these organisms has major impacts on element cycling by redox processes, pH balances, mineral dissolution/precipitations, and electro migration of ions in marine sediment. The ability of Desulfubulbus filaments to bridge...

  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

    be coupled by electric currents in nature. Here we provide evidence that electric currents running through defaunated sediment couple oxygen consumption at the sediment surface to oxidation of hydrogen sulphide and organic carbon deep within the sediment. Altering the oxygen concentration in the sea water...... 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. 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

    Some bacteria are capable of extracellular electron transfer, thereby enabling them to use electron acceptors and donors without direct cell contact 1, 2, 3, 4 . Beyond the micrometre scale, however, no firm evidence has previously existed that spatially segregated biogeochemical processes can...... be coupled by electric currents in nature. Here we provide evidence that electric currents running through defaunated sediment couple oxygen consumption at the sediment surface to oxidation of hydrogen sulphide and organic carbon deep within the sediment. Altering the oxygen concentration in the sea water...... 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...

  15. Determination of methylmercury in marine sediment samples: Method validation and occurrence data

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco, Luis; Vassileva, Emilia, E-mail: e.vasileva-veleva@iaea.org

    2015-01-01

    Highlights: • A method for MeHg determination at trace level in marine sediments is completely validated. • Validation is performed according to ISO-17025 and Eurachem guidelines. • The extraction efficiency of four sample preparation procedures is evaluated. • The uncertainty budget is used as a tool for evaluation of main uncertainty contributors. • Comparison with independent methods yields good agreement within stated uncertainty. - Abstract: The determination of methylmercury (MeHg) in sediment samples is a difficult task due to the extremely low MeHg/THg (total mercury) ratio and species interconversion. Here, we present the method validation of a cost-effective fit-for-purpose analytical procedure for the measurement of MeHg in sediments, which is based on aqueous phase ethylation, followed by purge and trap and hyphenated gas chromatography–pyrolysis–atomic fluorescence spectrometry (GC–Py–AFS) separation and detection. Four different extraction techniques, namely acid and alkaline leaching followed by solvent extraction and evaporation, microwave-assisted extraction with 2-mercaptoethanol, and acid leaching, solvent extraction and back extraction into sodium thiosulfate, were examined regarding their potential to selectively extract MeHg from estuarine sediment IAEA-405 certified reference material (CRM). The procedure based on acid leaching with HNO{sub 3}/CuSO{sub 4}, solvent extraction and back extraction into Na{sub 2}S{sub 2}O{sub 3} yielded the highest extraction recovery, i.e., 94 ± 3% and offered the possibility to perform the extraction of a large number of samples in a short time, by eliminating the evaporation step. The artifact formation of MeHg was evaluated by high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC–ICP–MS), using isotopically enriched Me{sup 201}Hg and {sup 202}Hg and it was found to be nonexistent. A full validation approach in line with ISO 17025 and

  16. Antimony speciation analysis in sediment reference materials using high-performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Potin-Gautier, M. [Laboratoire de Chimie Analytique, BioInorganique et Environnement LCABIE (UMR CNRS 3054), Universite de Pau et des pays de l' Adour, 64000 Pau (France); Pannier, F. [Laboratoire de Chimie Analytique, BioInorganique et Environnement LCABIE (UMR CNRS 3054), Universite de Pau et des pays de l' Adour, 64000 Pau (France)]. E-mail: Florence.pannier@univ-pau.fr; Quiroz, W. [Laboratoire de Chimie Analytique, BioInorganique et Environnement LCABIE (UMR CNRS 3054), Universite de Pau et des pays de l' Adour, 64000 Pau (France); Laboratorio de Quimica Analitica y Ambiental, Instituto de Quimica, Pontificia Universidad catolica de Valparaiso (Chile); Pinochet, H. [Laboratorio de Quimica Analitica y Ambiental, Instituto de Quimica, Pontificia Universidad catolica de Valparaiso (Chile); Gregori, I. de [Laboratorio de Quimica Analitica y Ambiental, Instituto de Quimica, Pontificia Universidad catolica de Valparaiso (Chile)

    2005-11-30

    This work presents the development of suitable methodologies for determination of the speciation of antimony in sediment reference samples. Liquid chromatography with a post-column photo-oxidation step and hydride generation atomic fluorescence spectrometry as detection system is applied to the separation and determination of Sb(III), Sb(V) and trimethylantimony species. Post-column decomposition and hydride generation steps were studied for sensitive detection with the AFS detector. This method was applied to investigate the conditions under which speciation analysis of antimony in sediment samples can be carried out. Stability studies of Sb species during the extraction processes of solid matrices, using different reagents solutions, were performed. Results demonstrate that for the extraction yield and the stability of Sb species in different marine sediment extracts, citric acid in ascorbic acid medium was the best extracting solution for antimony speciation analysis in this matrix (between 55% and 65% of total Sb was recovered from CRMs, Sb(III) being the predominant species). The developed method allows the separation of the three compounds within 6 min with detection limits of 30 ng g{sup -1} for Sb(III) and TMSbCl2 and 40 ng g{sup -1} for Sb(V) in sediment samples.

  17. Dynamic modeling of environmental risk associated with drilling discharges to marine sediments.

    Science.gov (United States)

    Durgut, İsmail; Rye, Henrik; Reed, Mark; Smit, Mathijs G D; Ditlevsen, May Kristin

    2015-10-15

    Drilling discharges are complex mixtures of base-fluids, chemicals and particulates, and may, after discharge to the marine environment, result in adverse effects on benthic communities. A numerical model was developed to estimate the fate of drilling discharges in the marine environment, and associated environmental risks. Environmental risk from deposited drilling waste in marine sediments is generally caused by four types of stressors: oxygen depletion, toxicity, burial and change of grain size. In order to properly model these stressors, natural burial, biodegradation and bioturbation processes were also included. Diagenetic equations provide the basis for quantifying environmental risk. These equations are solved numerically by an implicit-central differencing scheme. The sediment model described here is, together with a fate and risk model focusing on the water column, implemented in the DREAM and OSCAR models, both available within the Marine Environmental Modeling Workbench (MEMW) at SINTEF in Trondheim, Norway.

  18. Marine conservation in the republic of South Africa with special reference to marine parks and reserves

    Directory of Open Access Journals (Sweden)

    G.A. Robinson

    1977-01-01

    Full Text Available Conservation in the Republic of South Africa (RSA is dominated by big game and terrestrial reserves. Protecting these, have been in existence for many years. Recently Man has turned his attention more and more to the sea and due to adverse effects of pollution, overexploitation and habitat destruction the marine environment is threatened. However, conservationists have learnt lessons about both terrestrial and marine ecosystem-destruction and are now demanding with increasing persistence the establishment of marine parks and reserves.

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

    Science.gov (United States)

    Dell'Anno, Antonio; Beolchini, Francesca; Rocchetti, Laura; Luna, Gian Marco; Danovaro, Roberto

    2012-08-01

    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.

  20. Certified reference materials for radionuclides in Bikini Atoll sediment (IAEA-410) and Pacific Ocean sediment (IAEA-412)

    DEFF Research Database (Denmark)

    Pham, M. K.; van Beek, P.; Carvalho, F. P.

    2016-01-01

    The preparation and characterization of certified reference materials (CRMs) for radionuclide content in sediments collected offshore of Bikini Atoll (IAEA-410) and in the open northwest Pacific Ocean (IAEA-412) are described and the results of the certification process are presented. The certifi...

  1. Interaction of marine and fluvial clastic sedimentation, central Italy, Tyrrhenian coast

    Energy Technology Data Exchange (ETDEWEB)

    Evangelista, S.; Full, W.E.; Tortora, P.

    1989-03-01

    An integrated approach was used to study the interaction of fluvial, beach, and marine processes on sedimentation at the west-central coast of Italy along the Tyrrhenian Sea. The study area, 120 km northwest of Rome, is bounded on the north by Mt. Argentario, on the east by Pleistocene volcanics, on the south by the St. Augustine River, and on the west by the 50-mn bathymetric isopleth. The primary tools used included field work, textural analysis, high-resolution marine seismic, SEM, and Fourier shape analysis. Field work revealed incised streams, potentially relict beach ridges and lagoons, and relatively steep nearshore marine slopes in the northern portions of the study area. The result of the shape analysis performed on 56 samples was the definition of four end members. Each end member reflects a sedimentation process. Three end members were directly associated with fluvial sedimentation, and the fourth reflected marine processes. The seismic data along with the SEM analysis strongly supported the interpretation of four processes that dominate the recent sedimentation history. The sand interpreted to be associated with marine processes was found to represent the smoothest end member. SEM analysis suggests that the smoothing is not due to abrasion but to plastering associated with biologic processes (digestion.) and/or with silica precipitation associated with clay alteration at the freshwater/saltwater interface.

  2. Diversity of cultivable actinobacteria in geographically widespread marine sediments.

    Science.gov (United States)

    Maldonado, Luis A; Stach, James E M; Pathom-aree, Wasu; Ward, Alan C; Bull, Alan T; Goodfellow, Michael

    2005-01-01

    Reports describing actinobacteria isolated from marine environments have been dominated by Micromonospora, Rhodococcus and Streptomyces species. Recent culture-independent studies have shown that marine environments contain a high diversity of actinobacterial species that are rarely, if at all, recovered by cultivation-based methods. In this study, it is shown that cultivation-independent methods can be used to guide the application of selective isolation methods. The detection of marine-derived actinobacterial species that have previously only been reported from terrestrial habitats is highlighted. This study provides good evidence that the previously described low diversity of actinobacterial species isolated from marine environments does not reflect an actual low species diversity, and that the use of informed selective isolation procedures can aid in the isolation of members of novel taxa.

  3. 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

  4. 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.

  5. 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...

  6. Scattering from Marine Sediments in a Very Shallow Water Environment

    Science.gov (United States)

    2015-12-28

    simulations. In the case of long-range ocean reverberation, several approximations for these expressions are developed, relevant for various environmental... scenarios and different types of interfaces, sea-surface, water- sediment interface, buried sediment interfaces, and bottom basement. The results are...described in [1] in adequate detail only for the case of plane wave scattering from a heterogeneous fluid medium with rough interfaces plane-layered

  7. Simulated oil release from oil-contaminated marine sediment in the Bohai Sea, China.

    Science.gov (United States)

    Yuan, Lingling; Han, Longxi; Bo, Wenjie; Chen, Hua; Gao, Wenshen; Chen, Bo

    2017-02-17

    There is a high degree of heavy oil partitioning into marine sediments when an oil spill occurs. Contaminated sediment, as an endogenous pollution source, can re-pollute overlying water slowly. In this study, a static oil release process and its effects in marine sediment was investigated through a series of experiments with reproductive heavy oil-contaminated marine sediment. The oil release process was accurately simulated with a Lagergren first-order equation and reached equilibration after 48h. The fitted curve for equilibrium concentration (C0) and first-order rate constant (k1) for sediment pollution levels exhibited a first-order log relationship. The instantaneous release rate (dCtdt) was also calculated. The C0 increased with increases in temperature and dissolved organic matter (DOM), and decreasing salinity. The k1 increased with temperature, but was not affected by DOM and salinity. These results can be used to better understand the fate of heavy oil in contaminated sediments of the Bohai Sea.

  8. Organic pollutants in sediment cores of NE-Germany: Comparison of the marine Arkona Basin with freshwater sediments

    Energy Technology Data Exchange (ETDEWEB)

    Ricking, M. [Free University Berlin, Malteserstr. 74-100, 12249 Berlin (Germany)]. E-mail: ricking@zedat.fu-berlin.de; Koch, M. [Free University Berlin, Malteserstr. 74-100, 12249 Berlin (Germany); Rotard, W. [Free University Berlin, Malteserstr. 74-100, 12249 Berlin (Germany)

    2005-12-15

    During a contamination survey in NE-Germany sediment cores were sampled at 5 locations with freeze-coring devices and conventional box-coring systems. In total more than 40 samples were analysed for several organic compounds (136 PCDD/F, 33 PCB, 39 PAH, 10 DDX, 4 HCH, 4 CB), sedimentological parameters (TOC, TC, TIC, LOI), some total trace metals (Pb, Cd, Cr, Cu, Zn) and dated by measurement of the {sup 21}Pb and {sup 137}Cs activity. The deepest segment of the cores from the Arkona Basin and the freshwater lakes were dated back to the end of the 19th century. A comparison of marine versus freshwater data is presented. The contamination levels of Arkona Basin were often lower than anthropogenically influenced freshwater sediments and more similar to a freshwater sediment core only influenced by deposition, with an additional Oder River inflow. Differences in patterns and contamination levels are discussed.

  9. A small-scale, portable method for extracting microplastics from marine sediments.

    Science.gov (United States)

    Coppock, Rachel L; Cole, Matthew; Lindeque, Penelope K; Queirós, Ana M; Galloway, Tamara S

    2017-07-19

    Microplastics (plastic particles, 0.1 μm-5 mm in size) are widespread marine pollutants, accumulating in benthic sediments and shorelines the world over. To gain a clearer understanding of microplastic availability to marine life, and the risks they pose to the health of benthic communities, ecological processes and food security, it is important to obtain accurate measures of microplastic abundance in marine sediments. To date, methods for extracting microplastics from marine sediments have been disadvantaged by complexity, expense, low extraction efficiencies and incompatibility with very fine sediments. Here we present a new, portable method to separate microplastics from sediments of differing types, using the principle of density floatation. The Sediment-Microplastic Isolation (SMI) unit is a custom-built apparatus which consistently extracted microplastics from sediments in a single step, with a mean efficiency of 95.8% (±SE 1.6%; min 70%, max 100%). Zinc chloride, at a density of 1.5 g cm(-3), was deemed an effective and relatively inexpensive floatation media, allowing fine sediment to settle whilst simultaneously enabling floatation of dense polymers. The method was validated by artificially spiking sediment with low and high density microplastics, and its environmental relevance was further tested by extracting plastics present in natural sediment samples from sites ranging in sediment type; fine silt/clay (mean size 10.25 ± SD 3.02 μm) to coarse sand (mean size 149.3 ± SD 49.9 μm). The method presented here is cheap, reproducible and is easily portable, lending itself for use in the laboratory and in the field, eg. on board research vessels. By employing this method, accurate estimates of microplastic type, distribution and abundance in natural sediments can be achieved, with the potential to further our understanding of the availability of microplastics to benthic organisms. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All

  10. Electrophoretic Extraction and Proteomic Characterization of Proteins Buried in Marine Sediments

    Directory of Open Access Journals (Sweden)

    Eli K. Moore

    2014-10-01

    Full Text Available Proteins are the largest defined molecular component of marine organic nitrogen, and hydrolysable amino acids, the building blocks of proteins, are important components of particulate nitrogen in marine sediments. In oceanic systems, the largest contributors are phytoplankton proteins, which have been tracked from newly produced bloom material through the water column to surface sediments in the Bering Sea, but it is not known if proteins buried deeper in sediment systems can be identified with confidence. Electrophoretic gel protein extraction methods followed by proteomic mass spectrometry and database searching were used as the methodology to identify buried phytoplankton proteins in sediments from the 8–10 cm section of a Bering Sea sediment core. More peptides and proteins were identified using an SDS-PAGE tube gel than a standard 1D flat gel or digesting the sediment directly with trypsin. The majority of proteins identified correlated to the marine diatom, Thalassiosira pseudonana, rather than bacterial protein sequences, indicating an algal source not only dominates the input, but also the preserved protein fraction. Abundant RuBisCO and fucoxanthin chlorophyll a/c binding proteins were identified, supporting algal sources of these proteins and reinforcing the proposed mechanisms that might protect proteins for long time periods. Some preserved peptides were identified in unexpected gel molecular weight ranges, indicating that some structural changes or charge alteration influenced the mobility of these products during electrophoresis isolation. Identifying buried photosystem proteins suggests that algal particulate matter is a significant fraction of the preserved organic carbon and nitrogen pools in marine sediments.

  11. 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.

  12. 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).

  13. 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.

  14. 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

  15. Monitoring of the booster biocide dichlofluanid in water and marine sediment of Greek marinas

    NARCIS (Netherlands)

    Hamwijk, C.; Schouten, A.; Foekema, E.M.; Ravensberg, J.C.; Collombon, M.T.; Schmidt, K.; Kugler, M.

    2005-01-01

    Dichlofluanid (N-dichlorofluoromethylthio-N′-dimethyl-N- phenylsulphamide) is used as booster biocide in antifouling paints. The occurrence of dichlofluanid and its metabolite DMSA (N′-dimethyl-N-phenyl- sulphamide) was monitored in seawater and marine sediment from three Greek marinas. Seawater and

  16. Targeted search for actinomycetes from nearshore and deep-sea marine sediments.

    Science.gov (United States)

    Prieto-Davó, Alejandra; Villarreal-Gómez, Luis J; Forschner-Dancause, Stephanie; Bull, Alan T; Stach, James E M; Smith, David C; Rowley, Dave C; Jensen, Paul R

    2013-06-01

    Sediment samples collected off the coast of San Diego were analyzed for actinomycete diversity using culture-independent techniques. Eight new operational taxonomic units (OTUs) in the Streptomycetaceae were identified as well as new diversity within previously cultured marine OTUs. Sequences belonging to the marine actinomycete genus Salinispora were also detected, despite the fact that this genus has only been reported from more tropical environments. Independent analyses of marine sediments from the Canary Basin (3814 m) and the South Pacific Gyre (5126 and 5699 m) also revealed Salinispora sequences providing further support for the occurrence of this genus in deep-sea sediments. Efforts to culture Salinispora spp. from these samples have yet to be successful. This is the first report of Salinispora spp. from marine sediments > 1100 m and suggests that the distribution of this genus is broader than previously believed. © 2013 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  17. Sorption behaviors of a persistent toxaphene congener on marine sediments under different physicochemical conditions.

    Science.gov (United States)

    Soubaneh, Youssouf Djibril; Gagné, Jean-Pierre; Lebeuf, Michel; Gouteux, Bruno; Nikiforov, Vladimir; Awaleh, Mohamed Osman

    2014-11-01

    Sorptive processes are important parameters affecting the mobility, availability and fate of persistent organic pollutants (POPs), such as toxaphene, in aquatic systems. The sorption and desorption behaviors of the B7-1450, a stable toxaphene congener in environment, on marine sediment was studied under different temperature and salinity conditions to better understand the B-1450 distribution in estuarine systems. The data were fitted to different sorption models to characterize sorption behaviors by evaluating sorption coefficients and sequestrated fraction of B7-1450 on sediments. High carbon-normalized sorption coefficients (Koc) of the B7-1450 were observed with values ranging from 3.2×104 to 6.0×104 mL g(-1) under experimental conditions. The data showed an increase of B7-1450 sorption coefficients with the salinity and a decrease with temperature. These investigations indicate that B7-1450 is three times more sequestred on sediments in cold (2°C, 30 psu) than in warm marine conditions (20°C, 30 psu). These results suggest that the mobility and bioavailable of B7-1450 or other POPs from the sediments could be less important in cold marine comparatively in warm marine and warm freshwater media. As a result of climate changes, the warming of mid and high latitudes coastal waters could enhance the mobility of POPs.

  18. 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

  19. Quantitative analysis of anaerobic oxidation of methane (AOM) in marine sediments: a modeling perspective

    NARCIS (Netherlands)

    Regnier, P.; Dale, A.W.; Arndt, S.; LaRowe, D.E.; Mogollon, J.M.; Van Cappellen, P.

    2011-01-01

    Recent developments in the quantitativemodeling of methane dynamics and anaerobic oxidation of methane (AOM) in marine sediments are critically reviewed. The first part of the review begins with a comparison of alternative kinetic models for AOM. The roles of bioenergetic limitations, intermediate c

  20. 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...

  1. Monitoring of the booster biocide dichlofluanid in water and marine sediment of Greek marinas

    NARCIS (Netherlands)

    Hamwijk, C.; Schouten, A.; Foekema, E.M.; Ravensberg, J.C.; Collombon, M.T.; Schmidt, K.; Kugler, M.

    2005-01-01

    Dichlofluanid (N-dichlorofluoromethylthio-N′-dimethyl-N- phenylsulphamide) is used as booster biocide in antifouling paints. The occurrence of dichlofluanid and its metabolite DMSA (N′-dimethyl-N-phenyl- sulphamide) was monitored in seawater and marine sediment from three Greek marinas. Seawater and

  2. Inhibitory effects of sodium azide on microbial growth in experimental resuspension of marine sediment.

    Science.gov (United States)

    Cabrol, Léa; Quéméneur, Marianne; Misson, Benjamin

    2017-02-01

    Sodium azide (NaN3) was evaluated as inhibitor of microbial growth and activity in marine sediment resuspensions by monitoring the abundance of free-living and sessile bacteria using both flow cytometry and qPCR methods. Results show that 50mM of NaN3 strongly inhibits bacterial growth under natural and enriched resource conditions.

  3. Model-based temperature measurement system development for marine methane hydrate-bearing sediments

    Energy Technology Data Exchange (ETDEWEB)

    Fukuhara, Masafumi; Sugiyama, Hitoshi; Igarashi, Juei; Fujii, Kasumi; Shun' etsu, Onodera; Tertychnyi, Vladimir; Shandrygin, Alexander; Pimenov, Viacheslav; Shako, Valery; Matsubayashi, Osamu; Ochiai, Koji

    2005-07-01

    This paper describes the effect of the sensor installation on the temperature of the hydrate-bearing sediments through modeling, how the system was deployed in Nankai Trough area in Japan, and the features of the marine methane hydrate temperature measurement system. (Author)

  4. 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

  5. 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

  6. Soil and freshwater and marine sediment food webs: their structure and function

    NARCIS (Netherlands)

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

  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. Anaerobic ammonium-oxidising bacteria: A biological source of the bacteriohopanetetrol stereoisomer in marine sediments

    Science.gov (United States)

    Rush, Darci; Sinninghe Damsté, Jaap S.; Poulton, Simon W.; Thamdrup, Bo; Garside, A. Leigh; Acuña González, Jenaro; Schouten, Stefan; Jetten, Mike S. M.; Talbot, Helen M.

    2014-09-01

    Bacterially-derived bacteriohopanepolyols (BHPs) are abundant, well preserved lipids in modern and paleo-environments. Bacteriohopanetetrol (BHT) is a ubiquitously produced BHP while its less common stereoisomer (BHT isomer) has previously been associated with anoxic environments; however, its biological source remained unknown. We investigated the occurrence of BHPs in Golfo Dulce, an anoxic marine fjord-like enclosure located in Costa Rica. The distribution of BHT isomer in four sediment cores and a surface sediment transect closely followed the distribution of ladderane fatty acids, unique biomarkers for bacteria performing anaerobic ammonium oxidation (anammox). This suggests that BHT isomer and ladderane lipids likely shared the same biological source in Golfo Dulce. This was supported by examining the BHP lipid compositions of two enrichment cultures of a marine anammox species ('Candidatus Scalindua profunda'), which were found to contain both BHT and BHT isomer. Remarkably, the BHT isomer was present in higher relative abundance than BHT. However, a non-marine anammox enrichment contained only BHT, which explains the infrequence of BHT isomer observations in terrestrial settings, and indicates that marine anammox bacteria are likely responsible for at least part of the environmentally-observed marine BHT isomer occurrences. Given the substantially greater residence time of BHPs in sediments, compared to ladderanes, BHT isomer is a potential biomarker for past anammox activity.

  9. Causes and ecological effects of resuspended contaminated sediments (RCS) in marine environments.

    Science.gov (United States)

    Roberts, David A

    2012-04-01

    Sediments act as a net sink for anthropogenic contaminants in marine ecosystems and contaminated sediments may have a range of toxicological effects on benthic fauna and associated species. When resuspended, however, particulate-bound contaminants may be remobilised into the water column and become bioavailable to an additional assemblage of species. Such resuspension occurs through a range of natural and anthropogenic processes each of which may be thought of as pulsed disturbances resulting in pulsed exposures to contaminants. Thus, it is important to understand not only the toxicological responses of organisms to resuspended contaminated sediments (RCS), but also the frequency, magnitude and duration of sediment disturbance events. Such information is rarely collected together with toxicological data. Rather, the majority of published studies (>50% of the articles captured in this review) have taken the form of fixed-duration laboratory-based exposures with individual species. While this research has clearly demonstrated that resuspension of contaminated sediments can liberate sediment-bound contaminants leading to toxicity and bioaccumulation under controlled conditions, the potential for ecological effects in the field is often unclear. Monitoring studies suggest that recurrent natural disturbances such as tides and waves may cause the majority of contaminant release in many environments. However, various processes also act to limit the spatial and temporal scales across which contaminants are remobilised to the most toxic dissolved state. Various natural and anthropogenic disturbances of contaminated sediments have been linked to both community-level and sub-lethal responses in exposed populations of invertebrates and fish in the field. Together these findings suggest that resuspension of contaminated sediments is a frequently recurring ecological threat in contaminated marine habitats. Further consideration of how marine communities respond to temporally

  10. Sulfur-Oxidizing Bacteria Mediate Microbial Community Succession and Element Cycling in Launched Marine Sediment.

    Science.gov (United States)

    Ihara, Hideyuki; Hori, Tomoyuki; Aoyagi, Tomo; Takasaki, Mitsuru; Katayama, Yoko

    2017-01-01

    A large amount of marine sediment was launched on land by the Great East Japan earthquake. Here, we employed both on-site and laboratory studies on the launched marine sediment to investigate the succession of microbial communities and its effects on geochemical properties of the sediment. Twenty-two-month on-site survey showed that microbial communities at the uppermost layer (0-2 mm depth) of the sediment changed significantly with time, whereas those at the deeper layer (20-40 mm depth) remained nearly unchanged and kept anaerobic microbial communities. Nine months after the incidence, various sulfur-oxidizing bacteria (SOB) prevailed in the uppermost layer, in which afterwards diverse chemoorganotrophic bacteria predominated. Geochemical analyses indicated that the concentration of metals other than Fe was lower in the uppermost layer than that in the deeper layer. Laboratory study was carried out by incubating the sediment for 57 days, and clearly indicated the dynamic transition of microbial communities in the uppermost layer exposed to atmosphere. SOB affiliated in the class Epsilonproteobacteria rapidly proliferated and dominated at the uppermost layer during the first 3 days, after that Fe(II)-oxidizing bacteria and chemoorganotrophic bacteria were sequentially dominant. Furthermore, the concentration of sulfate ion increased and the pH decreased. Consequently, SOB may have influenced the mobilization of heavy metals in the sediment by metal-bound sulfide oxidation and/or sediment acidification. These results demonstrate that SOB initiated the dynamic shift from the anaerobic to aerobic microbial communities, thereby playing a critical role in element cycling in the marine sediment.

  11. Distribution and sources of organic matter in surface marine sediments across the North American Arctic margin

    Science.gov (United States)

    Goñi, Miguel A.; O'Connor, Alison E.; Kuzyk, Zou Zou; Yunker, Mark B.; Gobeil, Charles; Macdonald, Robie W.

    2013-09-01

    As part of the International Polar Year research program, we conducted a survey of surface marine sediments from box cores along a section extending from the Bering Sea to Davis Strait via the Canadian Archipelago. We used bulk elemental and isotopic compositions, together with biomarkers and principal components analysis, to elucidate the distribution of marine and terrestrial organic matter in different regions of the North American Arctic margin. Marked regional contrasts were observed in organic carbon loadings, with the highest values (≥1 mg C m-2 sediment) found in sites along Barrow Canyon and the Chukchi and Bering shelves, all of which were characterized by sediments with low oxygen exposure, as inferred from thin layers (cutin acids) all indicate marked regional differences in the proportions of marine and terrigenous organic matter present in surface sediments. Regions such as Barrow Canyon and the Mackenzie River shelf were characterized by the highest contributions of land-derived organic matter, with compositional characteristics that suggested distinct sources and provenance. In contrast, sediments from the Canadian Archipelago and Davis Strait had the smallest contributions of terrigenous organic matter and the lowest organic carbon loadings indicative of a high degree of post-depositional oxidation.

  12. Microbial communities in marine sediments modify success of an invasive macrophyte.

    Science.gov (United States)

    Gribben, Paul E; Nielsen, Shaun; Seymour, Justin R; Bradley, Daniel J; West, Matthew N; Thomas, Torsten

    2017-08-29

    Invasive plants have extensive impacts on ecosystem function and biodiversity globally. Our inability to manage invasive species stems in part from a lack of understanding of the processes that control their successful establishment and spread. To date, studies have largely considered how above-ground processes control native/invasive plant interactions. Emerging research from terrestrial and wetland ecosystems demonstrates that below-ground processes under microbial control can determine the outcome of interactions between native and invasive plants. Whether sediment microbes modify the success of invasive macrophytes in marine ecosystems is untested, despite marine sediment microbes controlling many ecological processes (e.g. nutrient cycling) comparable to those in terrestrial ecosystems. We first show that sediment bacterial communities differ between the native seagrass Zostera capricorni and the invasive alga Caulerpa taxifolia and that those differences relate to functional changes in sulfur cycling between the macrophytes. Second, by experimentally manipulating the microbial communities we show that intact microbial communities in Z. capricorni sediments provide biotic resistance by reducing C. taxifolia fragment growth 119% compared to when they are inactive, and intact microbial communities in C. taxifolia sediments have positive feedbacks by increasing fragment growth 200%. Thus, similar to terrestrial ecosystems, microorganisms appear to indirectly control the success of invasive macrophytes in marine ecosystems.

  13. The Global Inventory of Methane Hydrate in Marine Sediments: A Theoretical Approach

    Directory of Open Access Journals (Sweden)

    Andrew Dale

    2012-07-01

    Full Text Available The accumulation of methane hydrate in marine sediments is controlled by a number of physical and biogeochemical parameters including the thickness of the gas hydrate stability zone (GHSZ, the solubility of methane in pore fluids, the accumulation of particulate organic carbon at the seafloor, the kinetics of microbial organic matter degradation and methane generation in marine sediments, sediment compaction and the ascent of deep-seated pore fluids and methane gas into the GHSZ. Our present knowledge on these controlling factors is discussed and new estimates of global sediment and methane fluxes are provided applying a transport-reaction model at global scale. The modeling and the data evaluation yield improved and better constrained estimates of the global pore volume within the modern GHSZ ( ≥ 44 × 1015 m3, the Holocene POC accumulation rate at the seabed (~1.4 × 1014 g yr−1, the global rate of microbial methane production in the deep biosphere (4−25 × 1012 g C yr−1 and the inventory of methane hydrates in marine sediments ( ≥ 455 Gt of methane-bound carbon.

  14. Bioremediation of contaminated marine sediments can enhance metal mobility due to changes of bacterial diversity.

    Science.gov (United States)

    Fonti, Viviana; Beolchini, Francesca; Rocchetti, Laura; Dell'Anno, Antonio

    2015-01-01

    Bioremediation strategies applied to contaminated marine sediments can induce important changes in the mobility and bioavailability of metals with potential detrimental consequences on ecosystem health. In this study we investigated changes of bacterial abundance and diversity (by a combination of molecular fingerprinting and next generation sequencing analyses) during biostimulation experiments carried out on anoxic marine sediments characterized by high metal content. We provide evidence that the addition of organic (lactose and/or acetate) and/or inorganic compounds to contaminated sediments determines a significant increase of bacterial growth coupled with changes in bacterial diversity and assemblage composition. Experimental systems supplied only with organic substrates were characterized by an increase of the relative importance of sulfate reducing bacteria belonging to the families Desulfobacteraceae and Desulfobulbaceae with a concomitant decrease of taxa affiliated with Flavobacteriaceae. An opposite effect was observed in the experimental treatments supplied also with inorganic nutrients. The increase of bacterial metabolism coupled with the increase of bacterial taxa affiliated with Flavobacteriaceae were reflected in a significant decrease of Cd and Zn associated with sedimentary organic matter and Pb and As associated with the residual fraction of the sediment. However, independently from the experimental conditions investigated no dissolution of metals occurred, suggesting a role of bacterial assemblages in controlling metal solubilization processes. Overall results of this study have allowed to identify key biogeochemical interactions influencing the metal behavior and provide new insights for a better understanding of the potential consequences of bio-treatments on the metal fate in contaminated marine sediments.

  15. Isolation strategies of marine-derived actinomycetes from sponge and sediment samples.

    Science.gov (United States)

    Hameş-Kocabaş, E Esin; Uzel, Ataç

    2012-03-01

    During the last two decades, discoveries of new members of actinomycetes and novel metabolites from marine environments have drawn attention to such environments, such as sediment and sponge. For the successful isolation of actinomycetes from marine environments, many factors including the use of enrichment and pre-treatment techniques, and the selection of growth media and antibiotic supplements should be taken into account. High-throughput cultivation is an innovative technique that mimics nature, eliminates undesired, fast-growing bacteria and creates suitable conditions for rare, slow-growing actinomycetes. This review comprehensively evaluates the traditional and innovative techniques and strategies used for the isolation of actinomycetes from marine sponge and sediment samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. 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

  17. A new analytical approach for monitoring microplastics in marine sediments.

    Science.gov (United States)

    Nuelle, Marie-Theres; Dekiff, Jens H; Remy, Dominique; Fries, Elke

    2014-01-01

    A two-step method was developed to extract microplastics from sediments. First, 1 kg sediments was pre-extracted using the air-induced overflow (AIO) method, based on fluidisation in a sodium chloride (NaCl) solution. The original sediment mass was reduced by up to 80%. As a consequence, it was possible to reduce the volume of sodium iodide (NaI) solution used for the subsequent flotation step. Recoveries of the whole procedure for polyethylene, polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polystyrene and polyurethane with sizes of approximately 1 mm were between 91 and 99%. After being stored for one week in a 35% H2O2 solution, 92% of selected biogenic material had dissolved completely or had lost its colour, whereas the tested polymers were resistant. Microplastics were extracted from three sediment samples collected from the North Sea island Norderney. Using pyrolysis gas chromatography/mass spectrometry, these microplastics were identified as PP, PVC and PET.

  18. 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....

  19. 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....

  20. Extraction and phylogenetic survey of extracellular and intracellular DNA in marine sediments

    DEFF Research Database (Denmark)

    Torti, Andrea

    and terrestrial origin. By reflecting the diversity of living organisms and ecological processes in the source environments (lands, oceans, or sediments themselves), eDNA may act as a repository of genetic information to help reconstruct the biodiversity and changes of past ecosystems. On the other hand...... in Aarhus Bay, mainly encompassing phyla Alveolata, Archaeplastida, Hacrobia, Opisthokonta, Rhizaria, and Stramenopiles, as well eukaryotic clades poorly represented in public databases. Clades of unambiguous planktonic origin were observed in sediment strata as deep as 10 meters below the seafloor......, indicating significant contribution of allochthonous eukaryotic sequences to the sedimentary DNA pool in Aarhus bay, and supporting the role of marine sediments underlying oxygenated water columns as genetic archives of eukaryotic biodiversity of marine ecosystems. The partitioning of eukaryotic DNA between...

  1. 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.

  2. 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.

  3. Occurrence and distribution of microplastics in marine sediments along the Belgian coast.

    Science.gov (United States)

    Claessens, Michiel; De Meester, Steven; Van Landuyt, Lieve; De Clerck, Karen; Janssen, Colin R

    2011-10-01

    Plastic debris is known to undergo fragmentation at sea, which leads to the formation of microscopic particles of plastic; the so called 'microplastics'. Due to their buoyant and persistent properties, these microplastics have the potential to become widely dispersed in the marine environment through hydrodynamic processes and ocean currents. In this study, the occurrence and distribution of microplastics was investigated in Belgian marine sediments from different locations (coastal harbours, beaches and sublittoral areas). Particles were found in large numbers in all samples, showing the wide distribution of microplastics in Belgian coastal waters. The highest concentrations were found in the harbours where total microplastic concentrations of up to 390 particles kg(-1) dry sediment were observed, which is 15-50 times higher than reported maximum concentrations of other, similar study areas. The depth profile of sediment cores suggested that microplastic concentrations on the beaches reflect the global plastic production increase.

  4. 20th-century glacial-marine sedimentation in Vitus Lake, Bering Glacier, Alaska, U.S.A.

    Science.gov (United States)

    Molnia, B.F.; Post, A.; Carlson, P.R.

    1996-01-01

    Vitus Lake, the ice-marginal basin at the southeastern edge of Bering Glacier, Alaska, U.S.A., is a site of modern, rapid, glacial-marine sedimentation. Rather than being a fresh-water lake, Vitus Lake is a tidally influenced, marine to brackish embayment connected to the Pacific Ocean by an inlet, the Seal River. Vitus Lake consists of five deep bedrock basins, separated by interbasinal highs. Glacial erosion has cut these basins as much as 250 m below sea level. High-resolution seismic reflection surveys conducted in 1991 and 1993 of four of Vitus Lake's basins reveal a complex, variable three-component acoustic stratigraphy. Although not fully sampled, the stratigraphy is inferred to be primarily glacial-marine units of (1) basal contorted and deformed glacial-marine and glacial sediments deposited by basal ice-contact processes and submarine mass-wasting; (2) acoustically well-stratified glacial-marine sediment, which unconformably overlies the basal unit and which grades upward into (3) acoustically transparent or nearly transparent glacial-marine sediment. Maximum thicknesses of conformable glacial-marine sediment exceed 100 m. All of the acoustically transparent and stratified deposits in Vitus Lake are modern in age, having accumulated between 1967 and 1993. The basins where these three-part sequences of "present-day" glacial-marine sediment are accumulating are themselves cut into older sequences of stratified glacial and glacial-marine deposits. These older units outcrop on the islands in Vitus Lake. In 1967, as the result of a major surge, glacier ice completely filled all five basins. Subsequent terminus retreat, which continued through August 1993, exposed these basins, providing new locations for glacial-marine sediment accumulation. A correlation of sediment thicknesses measured from seismic profiles at specific locations within the basins, with the year that each location became ice-free, shows that the sediment accumulation at some locations

  5. Extraction of climatic signals from fossil organic compounds in marine sediments up to 11.7 Ma old (IODP-U1318).

    Science.gov (United States)

    Farrés, Mireia; Martrat, Belen; de Mol, Ben; Grimalt, Joan O; Tauler, Romà

    2015-06-16

    This study focuses on the extraction of climate signals and processes using a combined approach which includes the analysis of a high number of lipid molecules in marine sediments, and the chemometric analysis of the acquired data. Neutral and acidic fractions of marine sediments from site IODP-U1318 (south-west of the UK, Porcupine Seabight) were quantified by GC-MS. The alkenone unsaturation index, U(k')37, was estimated from the composition of C37 alkenones and it was then used for the estimation of sea surface temperatures (SST) for reference. Principal component analysis (PCA), explained 77.45% of the total data variance, and differentiated neutral fraction GC-MS total ion current (TIC) profiles according to SST values of the different sediment sections. GC-MS TIC chromatograms were correlated to sea surface temperatures (SST) by partial least squares regression (PLSR). The compounds more robustly in line with SST values at each sediment section explained 93% of the SST variance and they were identified using the variable importance in projection (VIP) scores method. The proposed approach enables an objective identification of organic compounds sensitive to SST variability throughout complete chromatographic profiles. As a result of this multivariate unbiased approach, lipid composition of sediments was differentiated between compounds of marine (long chain n-alkanes, long chain n-alkan-1-ols) and terrestrial (short chain n-alkan1-ols, alkenols, cholesterol, squalene) origin, whose concentrations were directly and inversely correlated to SST, respectively.

  6. Characterisation of the dilute HCl extraction method for the identification of metal contamination in Antarctic marine sediments.

    Science.gov (United States)

    Snape, I; Scouller, R C; Stark, S C; Stark, J; Riddle, M J; Gore, D B

    2004-11-01

    A regional survey of potential contaminants in marine or estuarine sediments is often one of the first steps in a post-disturbance environmental impact assessment. Of the many different chemical extraction or digestion procedures that have been proposed to quantify metal contamination, partial acid extractions are probably the best overall compromise between selectivity, sensitivity, precision, cost and expediency. The extent to which measured metal concentrations relate to the anthropogenic fraction that is bioavailable is contentious, but is one of the desired outcomes of an assessment or prediction of biological impact. As part of a regional survey of metal contamination associated with Australia's past waste management activities in Antarctica, we wanted to identify an acid type and extraction protocol that would allow a reasonable definition of the anthropogenic bioavailable fraction for a large number of samples. From a kinetic study of the 1 M HCl extraction of two Certified Reference Materials (MESS-2 and PACS-2) and two Antarctic marine sediments, we concluded that a 4 h extraction time allows the equilibrium dissolution of relatively labile metal contaminants, but does not favour the extraction of natural geogenic metals. In a regional survey of 88 marine samples from the Casey Station area of East Antarctica, the 4 h extraction procedure correlated best with biological data, and most clearly identified those sediments thought to be contaminated by runoff from abandoned waste disposal sites. Most importantly the 4 h extraction provided better definition of the low to moderately contaminated locations by picking up small differences in anthropogenic metal concentrations. For the purposes of inter-regional comparison, we recommend a 4 h 1 M HCl acid extraction as a standard method for assessing metal contamination in Antarctica.

  7. Eukaryotic diversity in late Pleistocene marine sediments around a shallow methane hydrate deposit in the Japan Sea.

    Science.gov (United States)

    Kouduka, M; Tanabe, A S; Yamamoto, S; Yanagawa, K; Nakamura, Y; Akiba, F; Tomaru, H; Toju, H; Suzuki, Y

    2017-09-01

    Marine sediments contain eukaryotic DNA deposited from overlying water columns. However, a large proportion of deposited eukaryotic DNA is aerobically biodegraded in shallow marine sediments. Cold seep sediments are often anaerobic near the sediment-water interface, so eukaryotic DNA in such sediments is expected to be preserved. We investigated deeply buried marine sediments in the Japan Sea, where a methane hydrate deposit is associated with cold seeps. Quantitative PCR analysis revealed the reproducible recovery of eukaryotic DNA in marine sediments at depths up to 31.0 m in the vicinity of the methane hydrate deposit. In contrast, the reproducible recovery of eukaryotic DNA was limited to a shallow depth (8.3 m) in marine sediments not adjacent to the methane hydrate deposit in the same area. Pyrosequencing of an 18S rRNA gene variable region generated 1,276-3,307 reads per sample, which was sufficient to cover the biodiversity based on rarefaction curves. Phylogenetic analysis revealed that most of the eukaryotic DNA originated from radiolarian genera of the class Chaunacanthida, which have SrSO4 skeletons, the sea grass genus Zostera, and the seaweed genus Sargassum. Eukaryotic DNA originating from other planktonic fauna and land plants was also detected. Diatom sequences closely related to Thalassiosira spp., indicative of cold climates, were obtained from sediments deposited during the last glacial period (MIS-2). Plant sequences of the genera Alnus, Micromonas, and Ulmus were found in sediments deposited during the warm interstadial period (MIS-3). These results suggest the long-term persistence of eukaryotic DNA from terrestrial and aquatic sources in marine sediments associated with cold seeps, and that the genetic information from eukaryotic DNA from deeply buried marine sediments associated with cold seeps can be used to reconstruct environments and ecosystems from the past. © 2017 John Wiley & Sons Ltd.

  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. 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.

  10. Arsenic in marine sediments from French Mediterranean ports: geochemical partitioning, bioavailability and ecotoxicology.

    Science.gov (United States)

    Mamindy-Pajany, Yannick; Hurel, Charlotte; Géret, Florence; Galgani, François; Battaglia-Brunet, Fabienne; Marmier, Nicolas; Roméo, Michèle

    2013-03-01

    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 extraction procedure specifically developed for appraising arsenic mobility in sediments. Toxicity assessment was performed on sediment elutriates, solid phases and aqueous arsenic species as single substance using the embryo-toxicity test on oyster larvae (Crassostrea gigas) and the Microtox test with Vibrio fischeri. Toxicity results showed that all sediment samples presented acute and sub-chronic toxic effects on oyster larvae and bacteria, respectively. The Microtox solid phase test allow to discriminate As-contaminated samples from the less contaminated ones, suggesting that toxicity of whole sediment samples is related to arsenic content. Toxicity of dissolved arsenic species as single substance showed that Vibrio fischeri and oyster larvae are most sensitive to As(V) than As(III). The distribution coefficient (Kd) of arsenic in sediment samples was estimated using results obtained in chemical sequential extractions. The Kd value is greater in SM (450 Lkg(-1)) than in EST (55 Lkg(-1)), indicating that arsenic availability is higher for the most toxic sediment sample (Estaque port). This study demonstrates that arsenic speciation play an important role on arsenic mobility and its bioavailability in marine port sediments. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. 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.

  12. 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.

  13. Marine coastal sediments microbial hydrocarbon degradation processes: contribution of experimental ecology in the omics'era.

    Science.gov (United States)

    Cravo-Laureau, Cristiana; Duran, Robert

    2014-01-01

    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 degradation. In addition, we

  14. Factors influencing adsorption and desorption of trimethoprim on marine sediments: mechanisms and kinetics.

    Science.gov (United States)

    Li, Jia; Zhang, Hua

    2017-08-05

    Adsorption-desorption behavior of ionic antibiotics in natural aquatic environment is complex, especially in coastal or estuary area where influencing factors such as pH and salinity usually varied in a wide range. In this study, batch-type and stirred flow chamber (SFC) experiments were carried out to simulate the sorption-desorption behavior of trimethoprim (TMP) in seawater-sediment system. Equilibrium and kinetic modeling were carried out to determine the rate and extent of TMP sorption on two marine sediments with different properties. Sediment BHB (K d , 6.40 L kg(-1)) has a greater sorption capacity compared with sediment LZB (K d , 3.40 L kg(-1)), which is related to the higher content of organic carbon and clay of sediment BHB. Adsorption of TMP varied in the pH range of 6.9 to 8.1 with maximum adsorption at pH 7.4. Increasing salinity and presence of phosphate and nitrate led to decreased TMP sorption. Attenuated total reflection Fourier transform infrared (ATR-FTIR) analysis demonstrated the formation of hydrogen bond between TMP and marine sediments. Adsorption of TMP on marine sediments was a non-equilibrium process that can be described with second-order kinetic model. Our analysis suggested that chemical non-equilibrium was the rate controlling process and intraparticle diffusion was also involved in TMP adsorption. A moderate desorption percentage (16.4-22.8% for LZB and 32.5-42.0%for BHB) was observed. Overall, the results showed that environmental factors and time-dependent processes need to be considered in modeling the fate and transport of TMP in coastal/estuarine waters.

  15. Effects of organic matter addition on methylmercury formation in capped and uncapped marine sediments.

    Science.gov (United States)

    Ndungu, Kuria; Schaanning, Morten; Braaten, Hans Fredrik Veiteberg

    2016-10-15

    In situ subaqueous capping (ISC) of contaminated marine sediments is frequently proposed as a feasible and effective mitigation option. However, though effective in isolating mercury species migration into overlying water, capping can also alter the location and extent of biogeochemical zones and potentially enhance methylmercury (MeHg) formation in Hg-contaminated marine sediments. We carried out a boxcosm study to investigate whether the addition of organic carbon (OC) to Hg-contaminated marine sediments beneath an in situ cap would initiate and/or enhance MeHg formation of the inorganic Hg present. The study was motivated by ongoing efforts to remediate ca. 30,000 m(2) of Hg-contaminated seabed sediments from a Hg spill from the U864 WWII submarine wreck. By the time of sinking, the submarine is assumed to have been holding a cargo of ca. 65 tons of liquid Hg. Natural organic matter and petroleum hydrocarbons from fuels and lubricants in the wreck are potential sources of organic carbon that could potentially fuel MeHg formation beneath a future cap. The results of our study clearly demonstrated that introduction of algae OC to Hg-contaminated sediments, triggered high rates of MeHg production as long a there was sufficient OC. Thus, MeHg production was limited by the amount of organic carbon available. The study results also confirmed that, within the six-month duration of the study and in the absence of bioturbating fauna, a 3-cm sediment clay cap could effectively reduce fluxes of Hg species to the overlying water and isolate the Hg-contaminated sediments from direct surficial deposition of organic matter that could potentially fuel methylation.

  16. Algal and archaeal polyisoprenoids in a recent marine sediment

    DEFF Research Database (Denmark)

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

    2001-01-01

    the sediment section is indicated by significant concentrations of 2,6,10,15,19-pentamethylicosane (PMI) and of ether-bound phytane and biphytane. The PMI reaches a minimum delta value of -47 parts per thousand well below the transition zone. Its isotopic depletion could reflect either methanogenic...... or methanotrophic sources. The ether-bound lipids are isotopically uniform throughout the section and are presumed to derive from archaea that utilize a carbon source unaffected by the oxidation of methane....

  17. Gamma Emitters in Marine Sediments near the Columbia River.

    Science.gov (United States)

    Osterberg, C; Kulm, L D; Byrne, J V

    1963-03-08

    Samples from sediment cores collected at 26 different locations 5 to 35 miles offshore in and around Astoria Submarine Canyon were analyzed for gamma emitters. Chromium-51 and zinc-65 were the principal radio-nuclides found, although several fission products and natural potassium-40 were also present. Radioactivity fell off sharply with distance from the mouth of the Columbia River, indicating that the river serves as a common source of the artificial radionuclides.

  18. 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.

  19. The linkage 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 ka to 5.5 ka ago (deMenocal et al., 2000; McGee et al., 2013). 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. We present simulation results from a recent sensitivity study, where we demonstrate for the first time the direct link between dust accumulation in marine cores and changes in Saharan land surface during the Holocene. We have simulated timeslices of he 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. We prescribe mid-Holocene vegetation cover based on a vegetation reconstruction from pollen data (Hoelzmann et al., 1998) and mid-Holocene lake surface area is determined using a water routing and storage model (Tegen et al., 2002). 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 variation in dust accumulation in marine cores is likely related to a transition of the Saharan landscape during the Holocene and not due to changes in atmospheric or ocean conditions alone. Reference: deMenocal, P., Ortiz, J., Guilderson, T., Adkins, J., Sarnthein, M., Baker, L., and Yarusinsky, M.: Abrupt onset and termination of the African Humid Period:: rapid climate responses to gradual insolation forcing, Quaternary Science Reviews, 19, 347-361, 2000. Hoelzmann, P., Jolly, D., Harrison, S. P., Laarif, F

  20. The experimental study of in situ acoustic properties in marine sediments

    Science.gov (United States)

    Fu, Shungsheng

    1998-10-01

    Since 1991, mainly supported by the US Navy, we have conducted a long term study of acoustic properties in marine sediments, including instrumentation development and a series of comprehensive experimental studies in natural environments. Our research work emphasizes in situ acoustic properties at sonic frequency, which the US Navy supports for better sonar interpretation. This dissertation is a summary of the work our group has done in recent years. The acoustic lance is a new instrument developed to measure in situ acoustic properties of the uppermost several meters of the seafloor. By using the acoustic lance, we are able to study the acoustic properties of marine sediments in a variety of natural environments. This dissertation combines five papers which have been either published, submitted or will be submitted to journals. In this dissertation, I describe the configuration and working principle of the lance, a technique of signal processing based on geophysical inverse theory for the lance signals, and three experimental studies conducted in three natural environments-sediment ponds on Mid-Atlantic Ridge (deep sea pelagic ooze), Kiel Bay gassy deposit (gassy silty clay), and Oahu Island off shore sand deposit (shallow water carbonate sands). The three experimental studies not only add new in situ data to the catalog of acoustic properties of marine sediments, but also provide new insight into acoustic behavior of marine sediments in natural environments. One of the important advantages of the lance is to obtain in situ acoustic data that address depth dependence of acoustic properties in the uppermost seabed. For the sediment ponds of Mid-Atlantic Ridge, we reported the velocity profiles in the uppermost 5 m of the seafloor which suggest that there is an acoustic channel lying just below the seafloor. Sound energy remains within the channel in propagation. The lance data provide in situ velocities and acoustic signal characteristics in gas- bearing sediments

  1. Bioprospecting of Novel and Bioactive Compounds from Marine Actinomycetes Isolated from South China Sea Sediments.

    Science.gov (United States)

    Yang, Na; Song, Fuhang

    2017-09-16

    Marine actinomycetes are less investigated compared to terrestrial strains as potential sources of natural products. To date, few investigations have been performed on culturable actinomycetes associated with South China Sea sediments. In the present study, twenty-eight actinomycetes were recovered from South China Sea sediments after dereplication by traditional culture-dependent method. The 16S rRNA gene sequences analyses revealed that these strains related to five families and seven genera. Twelve representative strains possessed at least one of the biosynthetic genes coding for polyketide synthase I, II, and nonribosomal peptide synthetase. Four strains had anti-Mycobacterium phlei activities and five strains had activities against methicillin-resistant Staphylococcus aureus. 10 L-scale fermentation of strains Salinispora sp. NHF45, Nocardiopsis sp. NHF48, and Streptomyces sp. NHF86 were carried out for novel and bioactive compounds discovery. Finally, we obtained a novel α-pyrone compound from marine Nocardiopsis sp. NHF48, an analogue of paulomenol from marine Streptomyces sp. NHF86 and a new source of rifamycin B, produced by Salinispora sp. NHF45. The present study concluded that marine actinomycetes, which we isolated from South China Sea sediments, will be a suitable source for the development of novel and bioactive compounds.

  2. Bioremediation of petroleum hydrocarbons in anoxic marine sediments: consequences on the speciation of heavy metals.

    Science.gov (United States)

    Dell'Anno, Antonio; Beolchini, Francesca; Gabellini, Massimo; Rocchetti, Laura; Pusceddu, Antonio; Danovaro, Roberto

    2009-12-01

    We investigated the effects of biostimulation and bioagumentation strategies applied to harbor sediments displaying reducing conditions and high concentrations of petroleum hydrocarbons and heavy metals. We compared the microbial efficiency of hydrocarbon removal from sediments maintained for 60 days in anoxic conditions and inoculated with acetate, sulfate-reducing bacterial strains and acetate and sulfate-reducing bacteria. All treatments determined a significant increase in the microbial growth and significant decreases of hydrocarbon contents and of redox potential values. The addition of sulfate-reducing bacterial strains to the sediment was the most efficient treatment for the hydrocarbon removal. In all experiments, significant changes of the heavy metals' phase repartition were observed. The results reported here suggest that the biodegradation of petroleum hydrocarbons in anoxic marine sediments may be enhanced by stimulating microbial anaerobic metabolism, but care should be applied to monitor the potential changes in the mobility and bioavailability of heavy metals induced by bio-treatments.

  3. [Diversity and bioactivities of culturable marine actinobacteria isolated from mangrove sediment in Indian Ocean].

    Science.gov (United States)

    He, Jie; Zhang, Daofeng; Xu, Ying; Zhang, Xiaomei; Tang, Shukun; Xu, Lihua; Li, Wenjun

    2012-10-04

    In order to explore the diversity, antimicrobial activity and enzyme-producing activity of marine actinobacteria isolated from mangrove sediments in Indian Ocean. Eight sediments collected from mangrove sediments in Indian Ocean were treated by the plate dilution method and spread on 24 isolation media only containing sole carbon source for energy. Marine actinobacteria were isolated and identified by 16S rRNA gene sequence analysis. The antimicrobial activity and enzyme-producing activity of isolated strains were further detected by spot planting method. In total 139 representative strains were selected from 521 isolates, and they were further sequenced and performed phylogenetic analysis based on their 16S rRNA gene sequences. There were 35 strains identified as potential novel species. Antimicrobial activity was detected in Bacillus subtilis, Candida albicans, Escherichia coli, Staphylococcus aureus, Aspergillus niger. Enzyme-producing activity for protease cellulase, amylase and esterase were 36.5%, 26.5%, 22.4% and 15.9%, respectively. Diverse marine actinobacteria were discovered in mangrove sediment in Indian Ocean, which have antimicrobial and enzyme activity.

  4. Enhancement of nitrate-induced bioremediation in marine sediments contaminated with petroleum hydrocarbons by using microemulsions.

    Science.gov (United States)

    Zhang, Zhen; Zheng, Guanyu; Lo, Irene M C

    2015-06-01

    The effect of microemulsion on the biodegradation of total petroleum hydrocarbons (TPH) in nitrate-induced bioremediation of marine sediment was investigated in this study. It was shown that the microemulsion formed with non-ionic surfactant polyoxyethylene sorbitan monooleate (Tween 80), 1-pentanol, linseed oil, and either deionized water or seawater was stable when subjected to dilution by seawater. Desorption tests revealed that microemulsion was more effective than the Tween 80 solution or the solution containing Tween 80 and 1-pentanol to desorb TPH from marine sediment. In 3 weeks of bioremediation treatment, the injection of microemulsion and NO3 (-) seems to have delayed the autotrophic denitrification between NO3 (-) and acid volatile sulfide (AVS) in sediment compared to the control with NO3 (-) injection alone. However, after 6 weeks of treatment, the delaying effect of microemulsion on the autotrophic denitrification process was no longer observed. In the meantime, the four injections of microemulsion and NO3 (-) resulted in as high as 29.73 % of TPH degradation efficiency, higher than that of two injections of microemulsion and NO3 (-) or that of four or two injections of NO3 (-) alone. These results suggest that microemulsion can be potentially applied to enhance TPH degradation in the nitrate-induced bioremediation of marine sediment.

  5. A Structural Modelling Study on Marine Sediments Toxicity

    Directory of Open Access Journals (Sweden)

    Sorana D. Bolboacă

    2008-06-01

    Full Text Available Quantitative structure-activity relationship models were obtained by applying the Molecular Descriptor Family approach to eight ordnance compounds with different toxicity on five marine species (arbacia punctulata, dinophilus gyrociliatus, sciaenops ocellatus, opossum shrimp, and ulva fasciata. The selection of the best among molecular descriptors generated and calculated from the ordnance compounds structures lead to accurate monovariate models. The resulting models obtained for six endpoints proved to be accurate in estimation (the squared correlation coefficient varied from 0.8186 to 0.9997 and prediction (the correlation coefficient obtained in leave-one-out analysis varied from 0.7263 to 0.9984.

  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

    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...

  8. 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...

  9. Distribution of clay minerals in marine sediments off Chennai, Bay of Bengal, India: Indicators of sediment sources and transport processes .

    Digital Repository Service at National Institute of Oceanography (India)

    Veerasingam, S.; Venkatachalapathy, R.; Ramkumar, T.

    in a Perkin Elmer RX1 spectrometer. Pellets were scanned at room temperature (25°C) in the 4,000 – 400 cm –1 spectral range. To improve the signal to noise ratio for each spectrum, 100 interferograms with a spectral resolution of ±4 cm-1 were averaged... similar vibrational reflectance spectra in the middle region of the infrared spectrum and Fig. 2 shows assembled FTIR spectra of some selected marine sediment samples. The band from 3,600 to 3,650 cm-1 is attributed to n (O–H) vibrations of hydroxyl...

  10. Reconstruction of late Quaternary marine and terrestrial environmental conditions of Northwest Africa and Southeast Australia : a multiple organic proxy study using marine sediments

    NARCIS (Netherlands)

    Alfama Lopes dos Santos, R.

    2012-01-01

    NW Africa and SE Australia are regions which are particularly vulnerable to climate change. In this thesis, organic proxies are used from marine sediment cores to reconstruct past environmental conditions from these areas. In sediments from NW Africa, the UK'37 showed an efficient proxy for sea sur

  11. Formation of natural gas hydrates in marine sediments. Gas hydrate growth and stability conditioned by host sediment properties

    Science.gov (United States)

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

    2000-01-01

    The stability conditions of submarine gas hydrates (methane clathrates) are largely dictated by pressure, temperature, gas composition, and pore water salinity. However, the physical properties and surface chemistry of the host sediments also affect the thermodynamic state, growth kinetics, spatial distributions, and growth forms of clathrates. Our model presumes that gas hydrate behaves in a way analogous to ice in the pores of a freezing soil, where capillary forces influence the energy balance. Hydrate growth is inhibited within fine-grained sediments because of the excess internal phase pressure of small crystals with high surface curvature that coexist with liquid water in small pores. Therefore, the base of gas hydrate stability in a sequence of fine sediments is predicted by our model to occur at a lower temperature, and so nearer to the seabed than would be calculated from bulk thermodynamic equilibrium. The growth forms commonly observed in hydrate samples recovered from marine sediments (nodules, sheets, and lenses in muds; cements in sand and ash layers) can be explained by a requirement to minimize the excess of mechanical and surface energy in the system.

  12. Ubiquitous Presence and Novel Diversity of Anaerobic Alkane Degraders in Cold Marine Sediments.

    Science.gov (United States)

    Gittel, Antje; Donhauser, Johanna; Røy, Hans; Girguis, Peter R; Jørgensen, Bo B; Kjeldsen, Kasper U

    2015-01-01

    Alkanes are major constituents of crude oil and are released to the marine environment by natural seepage and from anthropogenic sources. Due to their chemical inertness, their removal from anoxic marine sediments is primarily controlled by the activity of anaerobic alkane-degrading microorganisms. To facilitate comprehensive cultivation-independent surveys of the diversity and distribution of anaerobic alkane degraders, we designed novel PCR primers that cover all known diversity of the 1-methylalkyl succinate synthase gene (masD/assA), which catalyzes the initial activation of alkanes. We studied masD/assA gene diversity in pristine and seepage-impacted Danish coastal sediments, as well as in sediments and alkane-degrading enrichment cultures from the Middle Valley (MV) hydrothermal vent system in the Pacific Northwest. MasD/assA genes were ubiquitously present, and the primers captured the diversity of both known and previously undiscovered masD/assA gene diversity. Seepage sediments were dominated by a single masD/assA gene cluster, which is presumably indicative of a substrate-adapted community, while pristine sediments harbored a diverse range of masD/assA phylotypes including those present in seepage sediments. This rare biosphere of anaerobic alkane degraders will likely increase in abundance in the event of seepage or accidental oil spillage. Nanomolar concentrations of short-chain alkanes (SCA) were detected in pristine and seepage sediments. Interestingly, anaerobic alkane degraders closely related to strain BuS5, the only SCA degrader in pure culture, were found in mesophilic MV enrichments, but not in cold sediments from Danish waters. We propose that the new masD/assA gene lineages in these sediments represent novel phylotypes that are either fueled by naturally occurring low levels of SCA or that metabolize medium- to long-chain alkanes. Our study highlights that masD/assA genes are a relevant diagnostic marker to identify seepage and microseepage, e

  13. 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).

  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. Landslide-dammed paleolake perturbs marine sedimentation and drives genetic change in anadromous fish.

    Science.gov (United States)

    Mackey, Benjamin H; Roering, Joshua J; Lamb, Michael P

    2011-11-22

    Large bedrock landslides have been shown to modulate rates and processes of river activity by forming dams, forcing upstream aggradation of water and sediment, and generating catastrophic outburst floods. Less apparent is the effect of large landslide dams on river ecosystems and marine sedimentation. Combining analyses of 1-m resolution topographic data (acquired via airborne laser mapping) and field investigation, we present evidence for a large, landslide-dammed paleolake along the Eel River, CA. The landslide mass initiated from a high-relief, resistant outcrop which failed catastrophically, blocking the Eel River with an approximately 130-m-tall dam. Support for the resulting 55-km-long, 1.3-km(3) lake includes subtle shorelines cut into bounding terrain, deltas, and lacustrine sediments radiocarbon dated to 22.5 ka. The landslide provides an explanation for the recent genetic divergence of local anadromous (ocean-run) steelhead trout (Oncorhynchus mykiss) by blocking their migration route and causing gene flow between summer run and winter run reproductive ecotypes. Further, the dam arrested the prodigious flux of sediment down the Eel River; this cessation is recorded in marine sedimentary deposits as a 10-fold reduction in deposition rates of Eel-derived sediment and constitutes a rare example of a terrestrial event transmitted through the dispersal system and recorded offshore.

  16. 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...... for Crangon crangon and Solea solea, but not for Carcinus meanas and Pomatoschistus minutus. The validity of both behavioural tests was supported by in situ observations and investigations on the distribution of the species. It is concluded that both tests are useful tools in the assessment of the impact...

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

    DEFF Research Database (Denmark)

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

    redox half-reactions in distant regions of the sediment leads to formation of electrical fields, which modifies ion transport. The local proton producing and proton consuming half reactions induces pH extremes that accelerate dissolution of iron sulphides and calcium carbonates in anoxic layers...... 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....

  18. AMS measurement of 10Be concentrations in marine sediments from Chile Trench at the TANDAR laboratory

    Science.gov (United States)

    Rodrigues, D.; Arazi, A.; Fernández Niello, J. O.; Martí, G. V.; Negri, A. E.; Abriola, D.; Capurro, O. A.; Cardona, M. A.; de Barbará, E.; Gollan, F.; Hojman, D.; Pacheco, A. J.; Samsolo, N.; Togneri, M.; Villanueva, D.

    2017-03-01

    The 10Be/9Be ratios in marine sediments samples from the Southern Chile Trench have been measured using accelerator mass spectrometry (AMS). The samples were measured at the TANDAR accelerator, where the discrimination of the 10Be radionuclides was achieved by means of a passive absorber in front of an ionization chamber. This setup along with the high voltage available, provided a complete suppression of the 10B isobar interference. The obtained values for the 10Be concentrations, of the order of 109 atoms/g, are the first 10Be measurements from the Southern Chile Trench and offer an excellent tracer to quantitatively study the recycling of sediments in Andean magmas.

  19. 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.

  20. Amphipods from marine cave sediments of the southern Iberian Peninsula: diversity and ecological distribution

    Directory of Open Access Journals (Sweden)

    Carlos Navarro-Barranco

    2014-09-01

    Full Text Available The present study explores the amphipod assemblages of six marine caves on the Mediterranean coast of southern Spain. Replicate samples were taken both inside and outside each marine cave in order to characterize the amphipod fauna and the physicochemical properties of the sediment. As a result, 44 amphipods species were identified. The high number of species found in a relatively limited area highlighted the richness of the Alboran Sea fauna, which is mainly due to the mixture of species from different biogeographic areas. Harpinia genus was the dominant amphipod taxa inside marine caves and Perioculodes longimanus was also very abundant in the caverns. On the other hand, external communities were dominated by Siphonoecetes sabatieri, Metaphoxus fultoni and Photis longipes. There was a high degree of variability in both the internal and the external stations. Only the external station situated at low-medium depth showed a relatively homogeneous amphipod assemblage. The structure and behaviour of soft-bottom communities inside marine caves is difficult to predict because their environmental conditions depend on a particular combination of factors such as topography, depth and orientation. Therefore, no constant patterns were observed for species richness, Shannon diversity and abundance of amphipods in marine caves in comparison with open habitats. According to canonical correspondence analysis, sediment granulometry, organic matter and nitrogen concentration were the parameters that best explained the distribution of amphipods. Species were also classified by their tolerance to environmental pollution according to criteria followed by the Azti Marine Biotic Index and the BENTIX index. The great abundance of sensitive species at both the internal and external stations indicates the good ecological quality of the soft bottom studied. However, the suitability of biotic indices in marine caves should be tested in future studies.

  1. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

    ISAKSEN, MF; BAK, F.; JØRGENSEN, BB

    1994-01-01

    Sulfate reduction was measured with the (SO42-)-S-35-tracer technique in slurries of sediment from Aarhus Bay, Denmark, where seasonal temperatures range from 0 degrees to 15 degrees C. The incubations were made at temperatures from 0 degrees C to 80 degrees C in temperature increments of 2 degrees...... C to search for presence of psychrophilic, mesophilic and thermophilic sulfate-reducing bacteria. Detectable activity was initially only in the mesophilic range, but after a lag phase sulfate reduction by thermophilic sulfate-reducing bacteria were observed. No distinct activity of psychrophilic...... sulfate-reducing bacteria was detected. Time course experiments showed constant sulfate reduction rates at 4 degrees C and 30 degrees C, whereas the activity at 60 degrees C increased exponentially after a lag period of one day. Thermophilic, endospore-forming sulfate-reducing bacteria, designated strain...

  2. 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.

  3. Certified reference materials for radionuclides in Bikini Atoll sediment (IAEA-410) and Pacific Ocean sediment (IAEA-412).

    Science.gov (United States)

    Pham, M K; van Beek, P; Carvalho, F P; Chamizo, E; Degering, D; Engeler, C; Gascó, C; Gurriaran, R; Hanley, O; Harms, A V; Herrmann, J; Hult, M; Ikeuchi, Y; Ilchmann, C; Kanisch, G; Kis-Benedek, G; Kloster, M; Laubenstein, M; Llaurado, M; Mas, J L; Nakano, M; Nielsen, S P; Osvath, I; Povinec, P P; Rieth, U; Schikowski, J; Smedley, P A; Suplinska, M; Sýkora, I; Tarjan, S; Varga, B; Vasileva, E; Zalewska, T; Zhou, W

    2016-03-01

    The preparation and characterization of certified reference materials (CRMs) for radionuclide content in sediments collected offshore of Bikini Atoll (IAEA-410) and in the open northwest Pacific Ocean (IAEA-412) are described and the results of the certification process are presented. The certified radionuclides include: (40)K, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (234)U, (238)U, (239)Pu, (239+240)Pu and (241)Am for IAEA-410 and (40)K, (137)Cs, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (235)U, (238)U, (239)Pu, (240)Pu and (239+240)Pu for IAEA-412. The CRMs can be used for quality assurance and quality control purposes in the analysis of radionuclides in sediments, for development and validation of analytical methods and for staff training. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Effect of sulphate reducing bacteria on corrosion of Al-Zn-In-Sn sacrificial anodes in marine sediment

    Energy Technology Data Exchange (ETDEWEB)

    Liu, F. [Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Zhang, J.; Li, W.; Duan, J.; Hou, B. [Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Zhang, S. [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China)

    2012-05-15

    Microbiologically influenced corrosion (MIC) of Al-Zn-In-Sn sacrificial anodes in marine sediment was investigated by exposing samples to sulphate reducing bacteria (SRB). Samples exposed to the sterile marine sediment were used as control. The results show that pitting corrosion occurs in both the sterile marine sediment and the SRB-containing marine sediment. However, the corrosion can be increased sharply by the SRB metabolic activity due to the cathodic depolarization effect. In fact, the effect is based on the consumption of hydrogen which probably results in the acceleration of galvanic corrosion between corrosion products and metal substrate. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

    Science.gov (United States)

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

    2013-08-01

    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 determining the evolution of the Earth system. Therefore, recent developments in the quantitative modeling of organic matter degradation in marine sediments are critically reviewed. The first part of the review synthesizes the main chemical, biological and physical factors that control organic matter degradation in sediments while the second part provides a general review of the mathematical formulations used to model these processes and the third part evaluates their application over different spatial and temporal scales. Key transport mechanisms in sedimentary environments are summarized and the mathematical formulation of the organic matter degradation rate law is described in detail. The roles of enzyme kinetics, bioenergetics, temperature and biomass growth in particular are highlighted. Alternative model approaches that quantify the degradation rate constant are also critically compared. In the third part of the review, the capability of different model approaches to extrapolate organic matter degradation rates over a broad range of temporal and spatial scales is assessed. In addition, the structure, functions and parameterization of more than 250 published models of organic matter degradation in marine sediments are analyzed. The large range of published model parameters illustrates the complex nature of organic matter dynamics, and, thus, the limited transferability of these parameters from one site to another. Compiled model parameters do not reveal a statistically significant correlation with single environmental characteristics such as water depth, deposition rate or organic matter flux. The lack of a generic framework that allows for model parameters to be

  6. A New Natural Gamma Radiation Measurement System for Marine Sediment and Rock Analysis

    OpenAIRE

    Vasiliev, M. A.; Blum, P; Chubarian, G.; Olsen, R.; Bennight, C.; Cobine, T.; Fackler, D.; Hastedt, M.; Houpt, D.; Mateo, Z.; Vasilieva, Y. B.

    2010-01-01

    A new high-efficiency and low-background system for the measurement of natural gamma radioactivity in marine sediment and rock cores retrieved from beneath the seabed was designed, built, and installed on the JOIDES Resolution research vessel. The system includes eight large NaI(Tl) detectors that measure adjacent intervals of the core simultaneously, maximizing counting times and minimizing statistical error for the limited measurement times available during drilling expeditions. Effect to b...

  7. Impact of sulfide-oxidizing bacteria on the phosphorus cycle in marine sediments

    OpenAIRE

    Brock, Jörg

    2011-01-01

    Studies with the marine Beggiatoa strain 35Flor revealed that intracellular polyphosphate is rapidly degraded and phosphate is released in response to a switch from oxic to anoxic conditions at high sulfide concentrations. This new mode of polyphosphate usage drastically increases phosphate concentrations in the surrounding medium and helps to explain high phosphate concentrations in organic rich sediments of coastal upwelling areas, which enhance the chance of apatite precipitation. The unus...

  8. 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

  9. Stereochemistry of amino acids in surface samples of a marine sediment

    Science.gov (United States)

    Pollock, G. E.; Kvenvolden, K. A.

    1978-01-01

    In two surface samples of marine sediment, the percentages of D-alanine and D-aspartic acid are significantly higher than the other D-amino acids and are similar to the range found in soils. The percentage of D-glutamic acid is also higher than the other amino acids but less than D-alanine and D-aspartic acid. These D-amino acids may come mainly from bacteria.

  10. 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.

  11. 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.

  12. Arctic Sediment Transport from Land to Sea - An Integrated Study of Coastal - Marine Processes and Deposits in Dicksonfjorden, Svalbard

    Science.gov (United States)

    Jensen, M.; Choi, K.; Forwick, M.; Howe, J. A.; Husum, K.; Korsun, S.; Maat, D.; Nam, S. I.

    2016-12-01

    Valleys and fjords are the key transport and storage systems for sediments and biogeochemical elements from high arctic landscapes to the ocean. Sediment and nutrient fluxes are important for the biochemical cycle in the fjords and eventually in the ocean, and are important input data to earth system models. At present, high latitude systems are underrepresented in such models (Russell, 2014). Dicksonfjorden is a fjord in the larger Isfjorden system, Central Spitsbergen, Svalbard. It has no direct glacial input, in contrast to fjords affected by tidewater glaciers. The sediment supply is very high and the inner fjord receives sediment from a tide-influenced delta. This study is part of a multidisciplinary project aiming at mapping and quantifying sediment types and dispersal patterns in present Arctic valley - fjord systems and is the first comprehensive study of the depositional system in Dicksonfjorden. The first field campaign took place in summer 2016, when detailed mapping of the tidal delta and the sea floor in the inner fjord, coring onshore and offshore and sampling for foraminifera, nutrients and microbial abundances were performed. The surface mapping is based on high-resolution drone images, which will be processed to a high-resolution digital elevation model, and the bathymetry and sediment distribution data from the sea floor has been collected with a Gavia Offshore Surveyor AUV, providing high-resolution bathymetry and backscatter data of the seabed. Core transects from the delta surface will be described and compared to marine cores from the fjord basin retrieved from R/V Helmer Hanssen. Sediment accumulation rates will be assessed from 210Pb and 137Cs radionuclides. Preliminary results on the physical and chemical characteristics of the sedimentation system in inner Dicksonfjorden will be presented and implications for the fjord ecosystem will be discussed. References Russell , J.L., 2014. Control on the Latitudinal distribution of climate processes

  13. 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

  14. Relative Contribution of Endocrine-disrupting Chemicals to the Estrogenic Potency of Marine Sediments of Osaka Bay, Japan

    OpenAIRE

    KOYAMA, Jiro; KITOH, Asami; NAKAI, Makoto; KOHNO, Kumiko; Tanaka, Hiroyuki; Uno, Seiichi; コヤマ, ジロウ; キトウ, アサミ; ナカイ, マコト; コウノ, クミコ; タナカ, ヒロユキ; ウノ, セイイチ; 小山, 次朗; 中井, 誠; 河野, 久美子

    2013-01-01

    Although concentrations of endocrine-disrupting chemicals (EDCs) in seawaters of Japan are relatively low, vitellogenin and ovotestis inductions are still being observed in some males of mullet and flounder collected in coastal areas. These fish species are benthic and could be affected by EDCs in marine sediments. Therefore, the concentrations of EDCs in marine sediments of Osaka Bay were determined by LC-MS/MS. In addition, the estrogen receptor binding potencies as estrogenic potencies of ...

  15. 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

  16. 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)

  17. Gamma-emitting radionuclides in the shallow marine sediments off the Sindh coast, Arabian Sea.

    Science.gov (United States)

    Akram, M; Qureshi, Riffat M; Ahmad, Nasir; Solaija, Tariq Jamal

    2006-01-01

    Determination of gamma emitting radionuclides in shallow marine sediments off the Sindh coast has been carried out using a gamma spectrometry technique. The activity concentration measured in various sediment samples off the Sindh coast has been found to vary from 15.93 +/- 5.22 to 30.53 +/- 4.70 Bq kg(-1) for 226Ra, from 11.72 +/- 1.22 to 33.94 +/- 1.86 Bq kg(-1) for 228Ra and from 295.22 +/- 32.83 to 748.47 +/- 28.75 Bq kg(-1) for 40K. The calculated mean values of radium equivalent activity, absorbed dose rate and effective dose are 98 Bq kg(-1), 49 nGy h(-1) and 0.06 mSv y(-1), respectively. No artificial radionuclide was detected in the samples measured from the study area. As no data on radioactivity of the coastal environment of Pakistan are available, the data presented here will serve as baseline information on radionuclide concentration in shallow sea sediments off the Sindh coast. The data will also be useful for tracking pollution inventories from unusual radiological events (if any) in the territorial waters of the study area. Further, the information presented will contribute to modelling of a regional radioactivity database from the perspectives of the International Atomic Energy Agency's Asia-Pacific Marine Radioactivity Database and Global Marine Radioactivity Database.

  18. Species richness and adaptation of marine fungi from deep-subseafloor sediments.

    Science.gov (United States)

    Rédou, Vanessa; Navarri, Marion; Meslet-Cladière, Laurence; Barbier, Georges; Burgaud, Gaëtan

    2015-05-15

    The fungal kingdom is replete with unique adaptive capacities that allow fungi to colonize a wide variety of habitats, ranging from marine habitats to freshwater and terrestrial habitats. The diversity, importance, and ecological roles of marine fungi have recently been highlighted in deep-subsurface sediments using molecular methods. Fungi in the deep-marine subsurface may be specifically adapted to life in the deep biosphere, but this can be demonstrated only using culture-based analyses. In this study, we investigated culturable fungal communities from a record-depth sediment core sampled from the Canterbury Basin (New Zealand) with the aim to reveal endemic or ubiquist adapted isolates playing a significant ecological role(s). About 200 filamentous fungi (68%) and yeasts (32%) were isolated. Fungal isolates were affiliated with the phyla Ascomycota and Basidiomycota, including 21 genera. Screening for genes involved in secondary metabolite synthesis also revealed their bioactive compound synthesis potential. Our results provide evidence that deep-subsurface fungal communities are able to survive, adapt, grow, and interact with other microbial communities and highlight that the deep-sediment habitat is another ecological niche for fungi. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  19. [Impacts of pH and surfactants on adsorption behaviors of norfloxacin on marine sediments].

    Science.gov (United States)

    Pang, Hui-Ling; Yang, Gui-Peng; Gao, Xian-Chi; Cao, Xiao-Yan

    2012-01-01

    The adsorption behaviors of norfloxacin (NOR) on marine sediments at different pH values and in the presence of four different surfactants were systematically investigated by a batch equilibrium method. The results indicated that Freundlich adsorption isotherms fitted the adsorption behavior of NOR on marine sediments very well at different pH values. The Freundlich constant K(F) and the equilibrium adsorption amount of NOR reduced with the increase of pH values, and the minimum appeared at pH 8.10. The results suggested that cation exchange was the main adsorption mechanism of NOR at pH 6.01, while Van der Waals' force, hydrophobic effects, electrostatic force were the major adsorption mechanism of NOR on marine sediments at pH 8.10. The adsorption process fitted well with pseudo-second-order kinetic equations with the addition of surfactants. Our study also indicated that the addition of surfactants had the significant influence on the saturated adsorption amount of adsorption of NOR. The equilibrium adsorption amount (Q(e)) of NOR exhibited the following sequence: Q(e) (Tween80) < Q(e) (Tween20)

  20. Bulk Sediment and Diatom Silica Carbon Isotope Composition from Coastal Marine Sediments off East Antarctica

    NARCIS (Netherlands)

    Berg, S.; Leng, M.J.; Kendrick, C.P.; Cremer, H.; Wagner, B.

    2013-01-01

    Organic carbon occluded in diatom silica is assumed to be protected from degradation in the sediment. δ13C from diatom carbon (δ13C(diatom)) therefore potentially provides a signal of conditions during diatom growth. However, there have been few studies based on δ13C(diatom). Numerous variables can

  1. 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.

  2. MOLECULAR DIAGNOSTIC RATIOS TO ASSESS THE APPORTIONMENT OF PETROLEUM HYDROCARBONS CONTAMINANTION IN MARINE SEDIMENT

    Directory of Open Access Journals (Sweden)

    Agung Dhamar Syakti

    2016-11-01

    Full Text Available As maritime fulcrum nation, in Indonesia, marine environmental analytical chemistry field is still under developed. So that why, this review paper aims to provide basic understanding of the use some molecular diagnostic indices using n-alkanes indexes and polycyclic aromatic hydrocarbons (PAHs diagnostic ratios to estimate the source of apportionment of the hydrocarbons contamination and origin. The n-alkane chromatograms were then used to characterize the predominance of petrogenic or biogenic either terrestrial or aquatic. Furthermore, characterization allowed to discriminate riverine versus marine input. The occurrence of a broad unresolved complex mixture can be an evidence of biodegraded petroleum residues. For aromatic compounds, the prevalence of petrogenic, pyrolitic, and combustion-derived can be easily plotted by using isomers ratio calculation. This paper thus provides useful information on the hydrocarbon contamination origin, especially in marine sediments. Further researches should be undertaken in order to validate the use of molecular diagnostic ratio with isotopic approach.

  3. (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.

  4. 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.

  5. 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

  6. The impact of military activities on the concentration of mercury in soils of military training grounds and marine sediments.

    Science.gov (United States)

    Gębka, Karolina; Bełdowski, Jacek; Bełdowska, Magdalena

    2016-11-01

    Military activities have been conducted on land and at sea. Both during conflicts and in peace time, some regions served as a military training ground which included firing positions and bunkers. Mercury fulminate has been used in ammunition primers and detonators. Certain amount of ammunition was dumped into the Baltic Sea after the Second World War. Because of corroded containers, mercury can be released into the marine environment. The soil and sediment samples were taken from military training grounds, southern Baltic in 2014 and 2015. The concentration of mercury was determined by AMA-254 analyzer. Hg concentration was higher in the places of military activities, as compared to other areas. Ten times increased concentration of Hg was determined in soil sample collected in area of active gun range compared to the reference station. The significant higher concentration of mercury was detected in stations where chemical warfare agents were found.

  7. Unified classical formula for non-cohesive total-load sediment transport in marine coastal zones

    Science.gov (United States)

    Khorram, Saeed; Ergil, Mustafa

    2016-11-01

    This paper proposes the concept of a significant transport rate, in coastal environments that contains different spatial and temporal scales and multiple interacting forces (e.g., waves, tides, wave-current, and wind density currents) as well as, the complex physical processes of total-load sediment which is not easy to calculate for practical needs due to restricted range of applicability. The present study develops a unified classical formula for non-cohesive total-load sediment transport in marine coastal zones by using dimensional analysis and self-similarity concepts where a set of independent variables considered. A dataset of total-load collected at both field observation stations and from the laboratory flume conditions and the six well-known relevant formulas were used to evaluate the predictive capability of the proposed formula. Since the results show that, the new formula is in good agreement with both field and flume data sets measures, the authors are suggesting the use of it for the sediment-carrying capacity predictions of total-load sediment transport in marine coastal zones.

  8. A Chloroflexi bacterium dechlorinates polychlorinated biphenyls in marine sediments under in situ-like biogeochemical conditions.

    Science.gov (United States)

    Zanaroli, Giulio; Balloi, Annalisa; Negroni, Andrea; Borruso, Luigimaria; Daffonchio, Daniele; Fava, Fabio

    2012-03-30

    We investigated the reductive dechlorination of Aroclor 1254 PCBs by a coplanar PCB-dechlorinating microbial community enriched from an actual site contaminated marine sediment of the Venice lagoon in sterile slurry microcosms of the same sediment suspended in its site water, i.e., under biogeochemical conditions that closely mime those occurring in situ. The culture dechlorinated more than 75% of the penta- through hepta-chlorinated biphenyls to tri- and tetra-chlorinated congeners in 30 weeks. The dechlorination rate was reduced by the addition of H(2) and short chain fatty acids, which stimulated sulfate-reduction and methane production, and markedly increased by the presence of vancomycin or ampicillin. DGGE analysis of 16S rRNA genes on PCB-spiked and PCB-free cultures ruled out sulfate-reducing and methanogenic bacteria and revealed the presence of a single Chloroflexi phylotype closely related to the uncultured bacteria m-1 and SF1 associated to PCB dechlorination. These findings suggest that a single dechlorinator is responsible for the observed extensive dechlorination of Aroclor 1254 and that a Chloroflexi species similar to those already detected in freshwater and estuarine contaminated sediments mediates PCB dechlorination in the marine sediment adopted in this study under biogeochemical conditions resembling those occurring in situ in the Brentella Canal of Venice Lagoon.

  9. 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...

  10. Screening of secondary metabolite biosynthesis genes of marine actinomycetes isolated from Trabzon (Black Sea sea sediments

    Directory of Open Access Journals (Sweden)

    Kadriye Özcan

    2017-06-01

    Full Text Available In this study, active secondary metabolite production capacity of actinomycete isolates obtained from Trabzon (Black Sea sea sediments was investigated by molecular techniques. Totaly 24 actinomycetes were investigated by PCR based on the presence of secondary metabolite biosynthesis genes PKS / NRPS. According to the PCR results, 25 and 58% of actinomycetes obtained from Trabzon sea sediments were found to contain PKS-NRPS and only NRPS gene regions, respectively. When PCR data were evaluated, it was found that the production of the peptide form active secondary metabolite of the isolates by non-ribosomal way was higher than that of the secondary metabolite production by the PKS pathway. In addition, it has been determined that Black Sea marine sediments have high potential for active secondary metabolite production.

  11. Biodegradation of petroleum products in experimental plots in Antarctic marine sediments is location dependent.

    Science.gov (United States)

    Powell, Shane M; Harvey, Paul McA; Stark, Jonathan S; Snape, Ian; Riddle, Martin J

    2007-04-01

    Clean sediment collected from O'Brien Bay, East Antarctica, was artificially contaminated with a mix of Special Antarctic Blend diesel fuel and lubricating oil and deployed in two uncontaminated locations (O'Brien and Sparkes Bays) and a previously contaminated bay (Brown Bay) to evaluate whether a history of prior contamination would influence the biodegradation process. Detailed analysis of the hydrocarbon composition in the sediment after 11 weeks revealed different patterns of degradation in each bay. Biodegradation indices showed that hydrocarbon biodegradation occurred in all three bays but was most extensive in Brown Bay. This study shows that even within a relatively small geographical area, the longevity of hydrocarbons in Antarctic marine sediments can be variable. Our results are consistent with faster natural attenuation of spilt oil at sites with previous exposure to oil but further work is needed to confirm this. Such information would be useful when evaluating the true risk and longevity of oils spills.

  12. Molecular tools to understand the bioremediation effect of plants and earthworms on contaminated marine sediments.

    Science.gov (United States)

    Moreno, Beatriz; Cañizares, Rosa; Macci, Cristina; Doni, Serena; Masciandaro, Grazia; Benitez, Emilio

    2015-12-30

    A meso-scale pilot plant was set up to test the efficiency of a bioremediation scheme applied to marine sediments contaminated by heavy metals and hydrocarbons. The experiment was implemented for three years in two stages using two remediation agents: plants (Paspalum vaginatum and Tamarix gallica) and earthworms (Eisenia fetida). DNA and RNA-based methodologies were applied to elucidate the dynamics of the bacterial population and were related to improving biological and chemical conditions of the sediments. Bioremediation strategies were successful in removing pollutants from the contaminated sediments and specialization within the bacterial community related to the type of contamination present was detected in the different stages of the process. The highest response of Gram-positive PAH-degraders to the contamination was detected at the beginning and after the first stage of the experiment, corresponding to the uppermost values of degradation.

  13. 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

    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 environm......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...

  14. Petroleum hydrocarbon concentrations in marine sediments along Nagapattinam - Pondicherry coastal waters, Southeast coast of India.

    Science.gov (United States)

    Kamalakannan, K; Balakrishnan, S; Sampathkumar, P

    2017-04-15

    In this present study, petroleum hydrocarbons were statistically analyzed in three different coastal sediment cores viz., (N1, P1 and P2) from the Southeast coast of Tamil Nadu, India to examine the viability of PHCs. The significant positive relationship between mud (silt+clay+sand) and PHC unveiled that high specific surface of area of mud content raise the level of PHCs. Cluster analysis was used to discriminate the sediment samples based on their degree of contamination. The present study shows that instead of expensive and destructive PHC chemical methods, magnetic susceptibility is found to be a suitable, cheap and rapid method for detailed study of PHC in marine sediments. This baseline PHCs data can be used for regular ecological monitoring and effective management for the mining and tourism related activities in the coastal ecosystem. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Anthropogenic Forcing of Carbonate and Organic Carbon Preservation in Marine Sediments

    Science.gov (United States)

    Keil, Richard

    2017-01-01

    Carbon preservation in marine sediments, supplemented by that in large lakes, is the primary mechanism that moves carbon from the active surficial carbon cycle to the slower geologic carbon cycle. Preservation rates are low relative to the rates at which carbon moves between surface pools, which has led to the preservation term largely being ignored when evaluating anthropogenic forcing of the global carbon cycle. However, a variety of anthropogenic drivers—including ocean warming, deoxygenation, and acidification, as well as human-induced changes in sediment delivery to the ocean and mixing and irrigation of continental margin sediments—all work to decrease the already small carbon preservation term. These drivers affect the cycling of both carbonate and organic carbon in the ocean. The overall effect of anthropogenic forcing in the modern ocean is to decrease delivery of carbon to sediments, increase sedimentary dissolution and remineralization, and subsequently decrease overall carbon preservation.

  16. 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.

  17. Distribution of naturally occurring radionuclides activity concentration in East Malaysian marine sediment

    Energy Technology Data Exchange (ETDEWEB)

    Yii, M.W. [Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang (Malaysia)], E-mail: yii@nuclearmalaysia.gov.my; Zaharudin, A.; Abdul-Kadir, I. [Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang (Malaysia)

    2009-04-15

    Studies of naturally occurring radioactive materials (NORM) distribution of {sup 226}Ra, {sup 228}Ra and {sup 40}K in East Malaysia were carried out as part of a marine coastal environment project. The results of measurements will serve as baseline data and background reference level for Malaysia coastlines. Sediments from 21 coastal locations and 10 near shore locations were collected for analyses. The samples were dried, finely ground, sealed in a container and stored for a minimum of 30 days to establish secular equilibrium between {sup 226}Ra and {sup 228}Ra and their respective radioactive progenies. They were counted using a high-purity germanium (HPGe) spectrometer covering the respective progeny energy peak. For {sup 40}K, the presence of this was measured directly via its 1460 keV energy peak. The concentration of {sup 226}Ra, {sup 228}Ra and {sup 40}K in samples obtained from coastal Sarawak ranged between 23 and 41 (mean 30{+-}2) Bq/kg, 27 and 45 (mean 39{+-}4) Bq/kg and 142 and 680 (mean 462{+-}59) Bq/kg, respectively. Meanwhile, the concentration of {sup 226}Ra, {sup 228}Ra and {sup 40}K for samples obtained from coastal Sabah ranged between 16 and 30 (mean 23{+-}2) Bq/kg, 23 and 45 (mean 35{+-}4) Bq/kg and 402 and 842 (mean 577{+-}75) Bq/kg, respectively. For the Sarawak near shore stations, the concentration of {sup 226}Ra, {sup 228}Ra and {sup 40}K ranged between 11 and 36 (mean 22{+-}2) Bq/kg, 21 and 65 (mean 39{+-}5) Bq/kg and 149 and 517 (mean 309{+-}41) Bq/kg, respectively. Meanwhile, the concentration of {sup 226}Ra, {sup 228}Ra and {sup 40}K for samples obtained from Sabah ranged between 9 and 31 (mean 14{+-}2) Bq/kg, 10 and 48 (mean 21{+-}3) Bq/kg and 140 and 580 (mean 269{+-}36) Bq/kg, respectively. The calculated external hazard values of between 0.17 and 0.33 (less than unity) showed that there is little risk of external hazard to the workers handling the sediments.

  18. 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

  19. Performance evaluation of nitrogen isotope ratio determination in marine and lacustrine sediments: An inter-laboratory comparison

    NARCIS (Netherlands)

    Bahlmann, E.; Bernasconi, S.M.; Bouillon, S.; Houtekamer, M.; Korntheuer, M.; Langenberg, F.; Mayr, C.; Metzke, M.; Middelburg, J.J.; Nagel, B.; Struck, U.; Voß, M.; Emeis, K.C.

    2010-01-01

    Nitrogen isotopes of organic matter are increasingly studied in marine biogeochemistry and geology, plant and animal ecology, and paleoceanography. Here, we present results of an inter-laboratory test on determination of nitrogen isotope ratios in marine and lacustrine sediments. Six different

  20. 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

  1. 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

  2. Performance evaluation of nitrogen isotope ratio determination in marine and lacustrine sediments: An inter-laboratory comparison

    NARCIS (Netherlands)

    Bahlmann, E.; Bernasconi, S.M.; Bouillon, S.; Houtekamer, M.; Korntheuer, M.; Langenberg, F.; Mayr, C.; Metzke, M.; Middelburg, J.J.; Nagel, B.; Struck, U.; Voß, M.; Emeis, K.C.

    2010-01-01

    Nitrogen isotopes of organic matter are increasingly studied in marine biogeochemistry and geology, plant and animal ecology, and paleoceanography. Here, we present results of an inter-laboratory test on determination of nitrogen isotope ratios in marine and lacustrine sediments. Six different sampl

  3. Marine sediments and Beryllium-10 record of the geomagnetic moment variations during the Brunhes period.

    Science.gov (United States)

    Ménabréaz, Lucie; Thouveny, Nicolas; Bourlès, Didier; Demory, François

    2010-05-01

    Over millennial time scales, the atmospheric production of the cosmonuclid 10Be (half-life 1.387 ± 0.012 Ma [Shmeleff et al., 2009; Korschinek et al., 2009]) is modulated by the geomagnetic field strength, following a negative power law (e.g. Lal, 1988; Masarik and Beer, 2009). With respect to paleomagnetic reconstructions, 10Be-derived paleointensity records can therefore constitute an alternative, global and independent reading of the dipole moment variations. During the last years, efforts have been made to extract a geomagnetic signal from single and stacked 10Be records in natural archives such as ice and marine sediments (e.g. Carcaillet et al., 2004; Christl et al., 2007; Muscheler et al., 2005). In marine sediments, the 10Be concentration results from complex interplay of several processes: cosmogenic production, adsorption on sediment particles, redistribution by fluviatile and oceanic transport, and deposition. Therefore, a correction procedure is required to consider both sediment redistribution and enhanced scavenging, which can alter the primary signatures. To reconstruct the succession of field intensity lows accompanying excursions during the Brunhes chron, we investigated authigenic 10Be/9Be record of marine sequences also studied for paleomagnetism and oxygen isotopes. Mid and low latitude sites were preferred in order to benefit from the most efficient modulation by the magnetospheric shielding. We present a high resolution authigenic 10Be/9Be record of the last 50 ka recovered from the Portuguese Margin, that deciphers the cosmonuclide 10Be overproduction created by the geomagnetic dipole low associated with the Laschamp excursion. This record is compared to other proxy records of the geomagnetic field variations for the same time interval: (1) the relative paleointensity (RPI) reconstructed from the same sediments and the GLOPIS-75 record (Laj et al., 2004), (2) the absolute VDM record based on absolute paleointensities measured on lava flows

  4. 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

  5. Chemoautotrophic carbon fixation rates and active bacterial communities in intertidal marine sediments.

    Directory of Open Access Journals (Sweden)

    Henricus T S Boschker

    Full Text Available Chemoautotrophy has been little studied in typical coastal marine sediments, but may be an important component of carbon recycling as intense anaerobic mineralization processes in these sediments lead to accumulation of high amounts of reduced compounds, such as sulfides and ammonium. We studied chemoautotrophy by measuring dark-fixation of 13C-bicarbonate into phospholipid derived fatty acid (PLFA biomarkers at two coastal sediment sites with contrasting sulfur chemistry in the Eastern Scheldt estuary, The Netherlands. At one site where free sulfide accumulated in the pore water right to the top of the sediment, PLFA labeling was restricted to compounds typically found in sulfur and ammonium oxidizing bacteria. At the other site, with no detectable free sulfide in the pore water, a very different PLFA labeling pattern was found with high amounts of label in branched i- and a-PLFA besides the typical compounds for sulfur and ammonium oxidizing bacteria. This suggests that other types of chemoautotrophic bacteria were also active, most likely Deltaproteobacteria related to sulfate reducers. Maximum rates of chemoautotrophy were detected in first 1 to 2 centimeters of both sediments and chemosynthetic biomass production was high ranging from 3 to 36 mmol C m(-2 d(-1. Average dark carbon fixation to sediment oxygen uptake ratios were 0.22±0.07 mol C (mol O2(-1, which is in the range of the maximum growth yields reported for sulfur oxidizing bacteria indicating highly efficient growth. Chemoautotrophic biomass production was similar to carbon mineralization rates in the top of the free sulfide site, suggesting that chemoautotrophic bacteria could play a crucial role in the microbial food web and labeling in eukaryotic poly-unsaturated PLFA was indeed detectable. Our study shows that dark carbon fixation by chemoautotrophic bacteria is a major process in the carbon cycle of coastal sediments, and should therefore receive more attention in future

  6. Diversity of Nonribosomal Peptide Synthetase Genes in the AnticancerProducing Actinomycetes Isolated from Marine Sediment in Indonesia

    OpenAIRE

    Camelia Herdini; Shinta Hartanto; Sofia Mubarika; Bambang Hariwiyanto; Nastiti Wijayanti; Akira Hosoyama; Atsushi Yamazoe; Hideaki Nojiri; Jaka Widada

    2016-01-01

    Marine actinomycetes is a group of bacteria that is highly potential in producing novel bioactive compound. It has unique characteristics and is different from other terrestrial ones. Extreme environmental condition is suspected to lead marine actinomycetes produce different types of bioactive compound found previously. The aim of this study was to explore the presence and diversity of NRPS genes in 14 anticancer-producing actinomycetes isolated from marine sediment in Indonesia. ...

  7. Non-destructive X-ray Computed Tomography (XCT) Analysis of Sediment Variance in Marine Cores

    Science.gov (United States)

    Oti, E.; Polyak, L. V.; Dipre, G.; Sawyer, D.; Cook, A.

    2015-12-01

    Benthic activity within marine sediments can alter the physical properties of the sediment as well as indicate nutrient flux and ocean temperatures. We examine burrowing features in sediment cores from the western Arctic Ocean collected during the 2005 Healy-Oden TransArctic Expedition (HOTRAX) and from the Gulf of Mexico Integrated Ocean Drilling Program (IODP) Expedition 308. While traditional methods for studying bioturbation require physical dissection of the cores, we assess burrowing using an X-ray computed tomography (XCT) scanner. XCT noninvasively images the sediment cores in three dimensions and produces density sensitive images suitable for quantitative analysis. XCT units are recorded as Hounsfield Units (HU), where -999 is air, 0 is water, and 4000-5000 would be a higher density mineral, such as pyrite. We rely on the fundamental assumption that sediments are deposited horizontally, and we analyze the variance over each flat-lying slice. The variance describes the spread of pixel values over a slice. When sediments are reworked, drawing higher and lower density matrix into a layer, the variance increases. Examples of this can be seen in two slices in core 19H-3A from Site U1324 of IODP Expedition 308. The first slice, located 165.6 meters below sea floor consists of relatively undisturbed sediment. Because of this, the majority of the sediment values fall between 1406 and 1497 HU, thus giving the slice a comparatively small variance of 819.7. The second slice, located 166.1 meters below sea floor, features a lower density sediment matrix disturbed by burrow tubes and the inclusion of a high density mineral. As a result, the Hounsfield Units have a larger variance of 1,197.5, which is a result of sediment matrix values that range from 1220 to 1260 HU, the high-density mineral value of 1920 HU and the burrow tubes that range from 1300 to 1410 HU. Analyzing this variance allows us to observe changes in the sediment matrix and more specifically capture

  8. Quantitative analysis of anaerobic oxidation of methane (AOM) in marine sediments: A modeling perspective

    Science.gov (United States)

    Regnier, P.; Dale, A. W.; Arndt, S.; LaRowe, D. E.; Mogollón, J.; Van Cappellen, P.

    2011-05-01

    Recent developments in the quantitative modeling of methane dynamics and anaerobic oxidation of methane (AOM) in marine sediments are critically reviewed. The first part of the review begins with a comparison of alternative kinetic models for AOM. The roles of bioenergetic limitations, intermediate compounds and biomass growth are highlighted. Next, the key transport mechanisms in multi-phase sedimentary environments affecting AOM and methane fluxes are briefly treated, while attention is also given to additional controls on methane and sulfate turnover, including organic matter mineralization, sulfur cycling and methane phase transitions. In the second part of the review, the structure, forcing functions and parameterization of published models of AOM in sediments are analyzed. The six-orders-of-magnitude range in rate constants reported for the widely used bimolecular rate law for AOM emphasizes the limited transferability of this simple kinetic model and, hence, the need for more comprehensive descriptions of the AOM reaction system. The derivation and implementation of more complete reaction models, however, are limited by the availability of observational data. In this context, we attempt to rank the relative benefits of potential experimental measurements that should help to better constrain AOM models. The last part of the review presents a compilation of reported depth-integrated AOM rates (ΣAOM). These rates reveal the extreme variability of ΣAOM in marine sediments. The model results are further used to derive quantitative relationships between ΣAOM and the magnitude of externally impressed fluid flow, as well as between ΣAOM and the depth of the sulfate-methane transition zone (SMTZ). This review contributes to an improved understanding of the global significance of the AOM process, and helps identify outstanding questions and future directions in the modeling of methane cycling and AOM in marine sediments.

  9. Trace element storage capacity of sediments in dead Posidonia oceanica mat from a chronically contaminated marine ecosystem.

    Science.gov (United States)

    Di Leonardo, Rossella; Mazzola, Antonio; Cundy, Andrew B; Tramati, Cecilia Doriana; Vizzini, Salvatrice

    2017-01-01

    Posidonia oceanica mat is considered a long-term bioindicator of contamination. Storage and sequestration of trace elements and organic carbon (Corg ) were assessed in dead P. oceanica mat and bare sediments from a highly polluted coastal marine area (Augusta Bay, central Mediterranean). Sediment elemental composition and sources of organic matter have been altered since the 1950s. Dead P. oceanica mat displayed a greater ability to bury and store trace elements and Corg than nearby bare sediments, acting as a long-term contaminant sink over the past 120 yr. Trace elements, probably associated with the mineral fraction, were stabilized and trapped despite die-off of the overlying P. oceanica meadow. Mat deposits registered historic contamination phases well, confirming their role as natural archives for recording trace element trends in marine coastal environments. This sediment typology is enriched with seagrass-derived refractory organic matter, which acts mainly as a diluent of trace elements. Bare sediments showed evidence of inwash of contaminated sediments via reworking; more rapid and irregular sediment accumulation; and, because of the high proportions of labile organic matter, a greater capacity to store trace elements. Through different processes, both sediment typologies represent a repository for chemicals and may pose a risk to the marine ecosystem as a secondary source of contaminants in the case of sediment dredging or erosion. Environ Toxicol Chem 2017;36:49-58. © 2016 SETAC. © 2016 SETAC.

  10. 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 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.

  11. An integrated bioremediation process for petroleum hydrocarbons removal and odor mitigation from contaminated marine sediment.

    Science.gov (United States)

    Zhang, Zhen; Lo, Irene M C; Yan, Dickson Y S

    2015-10-15

    This study developed a novel integrated bioremediation process for the removal of petroleum hydrocarbons and the mitigation of odor induced by reduced sulfur from contaminated marine sediment. The bioremediation process consisted of two phases. In Phase I, acetate was dosed into the sediment as co-substrate to facilitate the sulfate reduction process. Meanwhile, akaganeite (β-FeOOH) was dosed in the surface layer of the sediment to prevent S(2-) release into the overlying seawater. In Phase II, NO3(-) was injected into the sediment as an electron acceptor to facilitate the denitrification process. After 20 weeks of treatment, the sequential integration of the sulfate reduction and denitrification processes led to effective biodegradation of total petroleum hydrocarbons (TPH), in which about 72% of TPH was removed. In Phase I, the release of S(2-) was effectively controlled by the addition of akaganeite. The oxidation of S(2-) by Fe(3+) and the precipitation of S(2-) by Fe(2+) were the main mechanisms for S(2-) removal. In Phase II, the injection of NO3(-) completely inhibited the sulfate reduction process. Most of residual AVS and S(0) were removed within 4 weeks after NO3(-) injection. The 16S rRNA clone library-based analysis revealed a distinct shift of bacterial community structure in the sediment over different treatment phases. The clones affiliated with Desulfobacterales and Desulfuromonadales were the most abundant in Phase I, while the clones related to Thioalkalivibrio sulfidophilus, Thiohalomonas nitratireducens and Sulfurimonas denitrificans predominated in Phase II.

  12. 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.

  13. Enhanced availability of mercury bound to dissolved organic matter for methylation in marine sediments

    Science.gov (United States)

    Mazrui, Nashaat M.; Jonsson, Sofi; Thota, Sravan; Zhao, Jing; Mason, Robert P.

    2016-12-01

    The forms of inorganic mercury (HgII) taken up and methylated by bacteria in sediments still remain largely unknown. From pure cultures studies, it has been suggested that dissolved organic matter (DOM) may facilitate the uptake either by acting as a shuttle molecule, transporting the HgII atom to divalent metal transporters, or by binding HgII and then being transported into the cell as a carbon source. Enhanced availability of Hg complexed to DOM has however not yet been demonstrated in natural systems. Here, we show that HgII complexed with DOM of marine origin was up to 2.7 times more available for methylation in sediments than HgII added as a dissolved inorganic complex (HgII(aq)). We argue that the DOM used to complex HgII directly facilitated the bacterial uptake of HgII whereas the inorganic dissolved HgII complex adsorbed to the sediment matrix before forming bioavailable dissolved HgII complexes. We further demonstrate that differences in net methylation in sediments with high and low organic carbon content may be explained by differences in the availability of carbon to stimulate the activity of Hg methylating bacteria rather than, as previously proposed, be due to differences in HgII binding capacities between sediments.

  14. Spatial distribution and source apportionment of PAHs in marine surface sediments of Prydz Bay, East Antarctica.

    Science.gov (United States)

    Xue, Rui; Chen, Ling; Lu, Zhibo; Wang, Juan; Yang, Haizhen; Zhang, Jie; Cai, Minghong

    2016-12-01

    This paper reports the concentrations of polycyclic aromatic hydrocarbons (PAHs) in marine sediments sampled from Prydz Bay, East Antarctica. Total PAH concentrations ranged from 12.95 to 30.93 ng/g, with a mean of 17.99 ± 5.57 ng/g. Two- and three-ring PAHs were the most abundant compounds found at the majority of the sampling stations of Prydz Bay. Long-range atmospheric transportation was found to play an important role in determining the spatial distribution of PAHs in the sediments sampled here. However, transport by ocean currents and release from melting glaciers were also found to influence PAH distributions in the sediments of East Antarctica. The vertical migration of PAHs in sediments showed a decreasing trend with depth, with higher concentrations in the relatively shallow-water regions (1000 m) of the Amery Basin and associated Canyons, respectively. A Pearson correlation analysis between PAH concentrations and sediment parameters demonstrated that PAHs has poor correlations with grain size, but has positive correlation with total organic carbon, indicated complex processing during transfer to remote environments. The results of qualitative and quantitative analyses indicate that the PAHs sampled here were derived mainly from a mixture of biomass combustion, traffic emissions, and petrogenic sources.

  15. Pleistocene reduction of polar ice caps: Evidence from Cariaco Basin marine sediments

    Science.gov (United States)

    Poore, R.Z.; Dowsett, H.J.

    2001-01-01

    Sea level is projected to rise between 13 and 94 cm over the next 100 yr due to continued climate warming. The sea-level projections assume that polar ice sheets will remain stable or even increase on time scales of centuries, but controversial geologic evidence suggests that current polar ice sheets have been eliminated or greatly reduced during previous Pleistocene interglacials indicating that modern polar ice sheets have become unstable within the natural range of interglacial climates. Sea level may have been more than 20 m higher than today during a presumably very warm interglacial about 400 ka during marine isotope stage 11. Because of the implications for future sea level rise, additional study of the conflicting evidence for warmer conditions and higher sea level during marine isotope stage 11 is needed. Here we present microfossil and isotopic data from marine sediments of the Cariaco Basin supporting the interpretation that global sea level was 10-20 m higher than today during marine isotope stage 11. The increased sea level requires reduction in modern polar ice sheets and is consistent with the interpretation that the West Antarctic ice sheet and the Greenland ice sheet were absent or greatly reduced during marine isotope stage 11. Our results show a warm marine isotope stage 11 interglacial climate with sea level as high as or above modern sea level that lasted for 25 to 30 k.y. Variations in Earth's orbit around the sun (Milankovitch cycles) are considered to be a primary external force driving glacial-interglacial cycles. Current and marine isotope stage 11 Milankovitch forcing are very similar, suggesting that the present interglacial (Holocene) that began ca. 10 ka will continue for another 15 to 20 k.y. Therefore any anthropogenic climate warming will accelerate the natural process toward reduction in polar ice sheets. The potential for increased rates of sea level rise related to polar ice sheet decay should be considered as a potential natural

  16. Unique actinomycetes from marine caves and coral reef sediments provide novel PKS and NRPS biosynthetic gene clusters.

    Science.gov (United States)

    Hodges, Tyler W; Slattery, Marc; Olson, Julie B

    2012-06-01

    In the ever-expanding search for novel bioactive molecules and enzymes, marine actinomycetes have proven to be a productive source. While open reef sediment and sponge-associated actinomycetes have been extensively examined, their marine cave counterparts remain unevaluated. Anchialine cave systems in the Bahamas offered an ideal setting to evaluate the occurrence and variation within sediment-associated actinomycete communities. While in close geographical proximity to open reef environments, these systems provide a specialized environmental niche devoid of light and direct exposure to nutrient input. In the present study, selective isolation techniques and molecular methods were used to test the hypothesis that variable distribution of actinomycetes and secondary metabolite gene clusters occur between open reef and marine cave systems. The results indicated that differences exist within the culturable sediment-associated actinomycete communities between marine caves and open reef systems, with members of the genus Streptomyces dominating cultures from open reef sediments and a more diverse suite of actinomycetes isolated from marine cave sediment samples. Within the cave isolates, members of the proposed genus Solwaraspora were the most represented. Based on PKS- and NRPS-gene-targeted PCR amplification and sequencing, geographic variation in the occurrence of these biosynthetic pathways was also observed. These findings indicate that marine cave systems are a lucrative source in the search for novel secondary metabolite producers with biotechnological applications and that environmental and geographic factors likely affect the occurrence of these biosynthetic pathways.

  17. 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.

  18. Redox effects on the microbial degradation of refractory organic matter in marine sediments

    Science.gov (United States)

    Reimers, Clare E.; Alleau, Yvan; Bauer, James E.; Delaney, Jennifer; Girguis, Peter R.; Schrader, Paul S.; Stecher, Hilmar A.

    2013-11-01

    Microbially mediated reduction-oxidation (redox) reactions are often invoked as being the mechanisms by which redox state influences the degradation of sedimentary organic matter (OM) in the marine environment. To evaluate the effects of elevated, oscillating and reduced redox potentials on the fate of primarily aged, mineral-adsorbed OM contained in continental shelf sediments, we used microbial fuel cells to control redox state within and around marine sediments, without amending the sediments with reducing or oxidizing substances. We subsequently followed electron fluxes in the redox elevated and redox oscillating treatments, and related sediment chemical, isotopic and bacterial community changes to redox conditions over a 748-day experimental period. The electron fluxes of the elevated and oscillating redox cells were consistent with models of organic carbon (OC) oxidation with time-dependent first-order rate constants declining from 0.023 to 0.005 y-1, in agreement with rate constants derived from typical OC profiles and down core ages of offshore sediments, or from sulfate reduction rate measurements in similar sediments. Moreover, although cumulative electron fluxes were higher in the continuously elevated redox treatment, incremental rates of electron harvesting in the two treatments converged over the 2 year experiment. These similar rates were reflected in chemical indicators of OM metabolism such as dissolved OC and ammonia, and particulate OC concentrations, which were not significantly different among all treatments and controls over the experimental time-scale. In contrast, products of carbonate and opal dissolution and metal mobilization showed greater enrichments in sediments with elevated and oscillating redox states. Microbial community composition in anode biofilms and surrounding sediments was assessed via high-throughput 16S rRNA gene sequencing, and these analyses revealed that the elevated and oscillatory redox treatments led to the

  19. Occurrence, distribution and ecological risk assessment of multiple classes of UV filters in marine sediments in Hong Kong and Japan.

    Science.gov (United States)

    Tsui, Mirabelle M P; Leung, H W; Kwan, Billy K Y; Ng, Ka-Yan; Yamashita, Nobuyoshi; Taniyasu, Sachi; Lam, Paul K S; Murphy, Margaret B

    2015-07-15

    Organic ultraviolet (UV) filters are used widely in various personal care products and their ubiquitous occurrence in the aquatic environment has been reported in recent years. However, data on their fate and potential impacts in marine sediments is limited. This study reports the occurrence and risk assessment of eleven widely used organic UV filters in marine sediment collected in Hong Kong and Tokyo Bay. Seven of the 11 target UV filters were detected in all sediment samples (median concentrations: ecological risk assessment showed that the likelihood of EHMC causing toxic effects on reproduction in snails was over 84% and 32% based on toxicity data for two species, respectively, suggesting potential risks of UV filters to benthic organisms and possible wider effects on the marine food web. However, more toxicity data for sediment organisms is necessary for better risk assessment of these compounds in benthic communities.

  20. The Link between Microbial Diversity and Nitrogen Cycling in Marine Sediments Is Modulated by Macrofaunal Bioturbation.

    Directory of Open Access Journals (Sweden)

    Maryam Yazdani Foshtomi

    Full Text Available The marine benthic nitrogen cycle is affected by both the presence and activity of macrofauna and the diversity of N-cycling microbes. However, integrated research simultaneously investigating macrofauna, microbes and N-cycling is lacking. We investigated spatio-temporal patterns in microbial community composition and diversity, macrofaunal abundance and their sediment reworking activity, and N-cycling in seven subtidal stations in the Southern North Sea.Our results indicated that bacteria (total and β-AOB showed more spatio-temporal variation than archaea (total and AOA as sedimentation of organic matter and the subsequent changes in the environment had a stronger impact on their community composition and diversity indices in our study area. However, spatio-temporal patterns of total bacterial and β-AOB communities were different and related to the availability of ammonium for the autotrophic β-AOB. Highest bacterial richness and diversity were observed in June at the timing of the phytoplankton bloom deposition, while richness of β-AOB as well as AOA peaked in September. Total archaeal community showed no temporal variation in diversity indices.Distance based linear models revealed that, independent from the effect of grain size and the quality and quantity of sediment organic matter, nitrification and N-mineralization were affected by respectively the diversity of metabolically active β-AOB and AOA, and the total bacteria, near the sediment-water interface. Separate models demonstrated a significant and independent effect of macrofaunal activities on community composition and richness of total bacteria, and diversity indices of metabolically active AOA. Diversity of β-AOB was significantly affected by macrofaunal abundance. Our results support the link between microbial biodiversity and ecosystem functioning in marine sediments, and provided broad correlative support for the hypothesis that this relationship is modulated by macrofaunal

  1. 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.

  2. Triassic deep-marine sedimentation in the western Qinling and Songpan terrane

    Institute of Scientific and Technical Information of China (English)

    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

  3. Ecotoxicological response of marine organisms to inorganic and organic sediment amendments in laboratory exposures.

    Science.gov (United States)

    Rosen, Gunther; Leather, James; Kan, Jinjun; Arias-Thode, Yolanda Meriah

    2011-10-01

    Experimental materials currently being investigated for use as amendments for the in situ remediation of contaminated sediments were assessed for their potential impacts on marine benthos. Laboratory toxicity tests involving lethal and sublethal endpoints were conducted on sediments amended with apatite, organoclay, chitin, or acetate, with the polychaete Neanthes arenaceodentata, the amphipod Eohaustorius estuarius, and the larval sheepshead minnow Cyprinodon variegatus. Amendments were mixed loosely into uncontaminated or metal-contaminated sediments, and also added inside experimental geotextile mats, at sediment dry weight (dw) concentrations ranging from 0.5% to 10%. The geotextile mats, containing apatite (5 or 10% dw), and/or organoclay (5%) did not result in adverse effects on any of the test organisms. Chitin and acetate, however, repetitively resulted in adverse effects on survival and/or adverse or positive effects on organism growth at concentrations of ≤ 2.5% dw. The adverse effects were attributed to water quality degradation in the exposure vessels (notably ammonia and dissolved oxygen concentration, for chitin and acetate, respectively) as a result of the microbial breakdown of the amendments. For N. arenaceodentata, growth was enhanced in the presence of chitin at concentrations as low as 0.5% sediment dw, which stimulated bacterial growth that may have provided an additional food source for the polychaete. Sediment chitin concentrations of 0.5% resulted in a statistically significant reduction in N. arenaceodentata body burdens of 61%, 29%, and 54%, relative to unamended contaminated sediment, for Cu, Zn, and Cd, respectively. The studies suggest a lack of inherent toxicity of these materials on the experimental organisms, as the adverse or positive responses observed are likely related to artifacts associated with laboratory exposure. Assessments in field settings are needed to verify this conclusion.

  4. Geochemical Evidence for Recent Hydrothermal Alteration of Marine Sediments in Mid-Okinawa Trough, Southwest Japan

    Science.gov (United States)

    Tanaka, A.; Abe, G.; Yamaguchi, K. E.

    2014-12-01

    Recent studies have shown that submarine hydrothermal system supports diverse microbial life. Bio-essential metals supporting such microbial communities were released from basalts by high-temperature water-rock interaction in deeper part of the oceanic crust and carried by submarine fluid flow. Its total quantity in global hydrothermal settings has been estimated to be on the order of ~1019 g/yr, which is surprisingly on the same order of the total river flows (Urabe et al., 2011). Therefore, it is important to explore how submarine river system works, i.e., to understand mechanism and extent of elemental transport, which should lead to understanding of the roles of hydrothermal circulation in oceanic crust in controlling elemental budget in the global ocean and geochemical conditions to support deep hot biosphere.  We performed REE analysis of marine sediments influenced by submarine hydrothermal activity in Mid-Okinawa Trough. The sediment samples used in this study are from IODP site at Iheya North region and JADE site at Izena region. The samples show alternation between volcanic and clastic sediments. Hydrothermal fluids of this area contain elevated concentrations of volatile components such as H2, CO2, CH4, NH4+, and H2S, supporting diverse chemoautotrophic microbial community (Nakagawa et al., 2005). The purpose of this study is to examine the effect of hydrothermal activity on the REE signature of the sediments. Chondrite-normalized REE patterns of the samples show relative enrichment of light over heavy REEs, weak positive Ce anomalies, and variable degrees of negative Eu anomalies. The REE patterns suggest the sediments source was mainly basalt, suggesting insignificant input of continental materials. Negative Eu anomalies found in the IODP site become more pronounced with increasing depth, suggesting progressive increase of hydrothermal alteration where Eu was reductively dissolved into fluids by decomposition of feldspars. Contrary, at the JADE site

  5. A multidisciplinary approach for assessing the toxicity of marine sediments: analysis of metal content and elutriate bioassays using metal bioavailability and genotoxicity biomarkers.

    Science.gov (United States)

    Frassinetti, Stefania; Pitzalis, Emanuela; Mascherpa, Marco Carlo; Caltavuturo, Leonardo; Morelli, Elisabetta

    2012-01-01

    The goal of this article is to verify the applicability of two different biological assays for studying a coastal area that is subject to anthropogenic inputs. Phytochelatins in the marine diatom Thalassiosira weissflogii were used as a biomarker of metal bioavailability. The frequency of genetic damage in the sensitive D7 strain of the yeast Saccharomyces cerevisiae was used to estimate the mutagenic potential. Biological assays were carried out using sediment elutriates. Sediments were collected at three selected sites located in the Gulf of Follonica (Tuscany, Italy), during a 2-year sampling period: Cala Violina (reference site) and the mouths of the rivers Pecora and Cornia, named sites V, P and C, respectively. The chemical characterization of each site was determined in terms of metal concentrations (As, Cd, Cr, Cu, Ni, Pb), measured in 11 sediment samples for each site. The results showed that metal concentrations in sediments from sites C and P were 2-10 times higher than the reference values (site V, year 2004). In addition, we found generally higher metal concentrations in the 2007 sediments than in the 2008 ones, including those of site V, due to the occurrence of an unexpected pollution event. This enabled us to obtain a pollution gradient to validate the proposed bioassays. In fact, the bioassays showed a potential biological hazard in the 2007 elutriates. Significant mutagenic effects were found in samples exhibiting higher concentrations of Cd and Cr. The induction of phytochelatins in T. weissflogii correlated positively with the Cd concentration in the elutriates.

  6. Mineralization of RDX-derived nitrogen to N2 via denitrification in coastal marine sediments.

    Science.gov (United States)

    Smith, Richard W; Tobias, Craig; Vlahos, Penny; Cooper, Christopher; Ballentine, Mark; Ariyarathna, Thivanka; Fallis, Stephen; Groshens, Thomas J

    2015-02-17

    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a common constituent of military explosives. Despite RDX contamination at numerous U.S. military facilities and its mobility to aquatic systems, the fate of RDX in marine systems remains largely unknown. Here, we provide RDX mineralization pathways and rates in seawater and sediments, highlighting for the first time the importance of the denitrification pathway in determining the fate of RDX-derived N. (15)N nitro group labeled RDX ((15)N-[RDX], 50 atom %) was spiked into a mesocosm simulating shallow marine conditions of coastal Long Island Sound, and the (15)N enrichment of N2 (δ(15)N2) was monitored via gas bench isotope ratio mass spectrometry (GB-IRMS) for 21 days. The (15)N tracer data were used to model RDX mineralization within the context of the broader coastal marine N cycle using a multicompartment time-stepping model. Estimates of RDX mineralization rates based on the production and gas transfer of (15)N2O and (15)N2 ranged from 0.8 to 10.3 μmol d(-1). After 22 days, 11% of the added RDX had undergone mineralization, and 29% of the total removed RDX-N was identified as N2. These results demonstrate the important consideration of sediment microbial communities in management strategies addressing cleanup of contaminated coastal sites by military explosives.

  7. Experimental Constraints on Microbial Liberation of Structural Iron from Common Clay Minerals in Marine Sediments

    Science.gov (United States)

    Metcalfe, K. S.; Gaines, R. R.; Trang, J.; Scott, S. W.; Crane, E. J.; Lackey, J.; Prokopenko, M. G.; Berelson, W.

    2013-12-01

    Iron is a limiting nutrient in many marine settings. The marine Fe-cycle is complex because Fe may be used as an electron donor or acceptor and cycled many times before ultimate burial in sediments. Thus, the availability of iron plays a large role in the marine carbon cycle, influencing not only the extent of primary productivity but also the oxidation of organic matter in sediments. The primary constituents of marine sediments are clay minerals, which commonly contain lattice-bound Fe in octahedral sites. In marine settings, the pool of Fe bound within silicate mineral lattices has long been considered reactive only over long timescales, and thus non-bioavailable. In vitro experimental evidence has shown that lab cultures of Fe-reducing bacteria are able to utilize structurally-bound Fe (III) from the crystal lattice of nontronite, an uncommon but particularly Fe-rich (> 12 wt.%) smectite. Importantly, this process is capable of liberating Fe (II) to solution, where it is available to biotic processes as an electron donor. In order to constrain the capacity of naturally-occurring marine bacteria to liberate structurally-coordinated Fe from the lattices of common clay minerals, we exposed a suite of 16 different clay minerals (0.8-13.9 wt.% Fe) to lab cultures of known Fe-reducer S. onenidensis MR-1 and to a natural consortium of Fe-reducing microbes from the San Pedro and Santa Monica Basins over timescales ranging from 7-120 days. Clay minerals were treated with Na-dithionite to extract surface-bound Fe prior to exposure. Crystallographic data and direct measurements of Fe in solution demonstrate the release of structural Fe from all clay minerals analyzed. Neoformation of illite and amorphous quartz were observed. The array of clay minerals and microbes used in this experiment complement past findings and suggest that common clay minerals may represent a large and previously unrecognized pool of bioavailable Fe in the world ocean that contributes significantly

  8. Shear-wave velocity of marine sediments offshore Taiwan using ambient seismic noise

    Science.gov (United States)

    Lin, Yu-Tse; Lin, Jing-Yi; Kuo-Chen, Hao; Yeh, Yi-Chin; Cheng, Win-Bin

    2017-04-01

    Seismic ambient noise technology has many advantages over the traditional two-station method. The most important one is that noise is happening all the time and it can be widely and evenly distributed. Thus, the Green's Function of any station pair can be obtained through the data cross-correlation process. Many related studies have been performed to estimate the velocity structures based on the inland area. Only a few studies were reported for the marine area due to the relatively shorter recording time of ocean bottom seismometers (OBS) deployment and the high cost of the marine experiment. However, the understanding about the shear-wave velocity (Vs) of the marine sediments is very crucial for the hazard assessment related to submarine landslides, particularly with the growing of submarine resources exploration. In this study, we applied the ambient noise technique to four OBS seismic networks located offshore Taiwan in the aim of getting more information about the noise sources and having the preliminary estimation for the Vs of the marine sediments. Two of the seismic networks were deployed in the NE part of Taiwan, near the Ryukyu subduction system, whereas the others were in the SW area, on the continental margin rich in gas hydrate. Generally, ambient seismic noise could be associated with wind, ocean waves, rock fracturing and anthropogenic activity. In the southwestern Taiwan, the cross-correlation function obtained from two seismic networks indicate similar direction, suggestion that the source from the south part of the network could be the origin of the noise. However, the two networks in the northeastern Taiwan show various source direction, which could be caused by the abrupt change of bathymetry or the volcanic degassing effect frequently observed by the marine geophysical method in the area. The Vs determined from the dispersion curve shows a relatively higher value for the networks in the Okinawa Trough (OT) off NE Taiwan than that in the

  9. Exploring the diversity and metabolic potential of actinomycetes from temperate marine sediments from Newfoundland, Canada.

    Science.gov (United States)

    Duncan, K R; Haltli, B; Gill, K A; Correa, H; Berrué, F; Kerr, R G

    2015-01-01

    Marine sediments from Newfoundland, Canada were explored for biotechnologically promising Actinobacteria using culture-independent and culture-dependent approaches. Culture-independent pyrosequencing analyses uncovered significant actinobacterial diversity (H'-2.45 to 3.76), although the taxonomic diversity of biotechnologically important actinomycetes could not be fully elucidated due to limited sampling depth. Assessment of culturable actinomycete diversity resulted in the isolation of 360 actinomycetes representing 59 operational taxonomic units, the majority of which (94 %) were Streptomyces. The biotechnological potential of actinomycetes from NL sediments was assessed by bioactivity and metabolomics-based screening of 32 representative isolates. Bioactivity was exhibited by 41 % of isolates, while 11 % exhibited unique chemical signatures in metabolomics screening. Chemical analysis of two isolates resulted in the isolation of the cytotoxic metabolite 1-isopentadecanoyl-3β-D-glucopyranosyl-X-glycerol from Actinoalloteichus sp. 2L868 and sungsanpin from Streptomyces sp. 8LB7. These results demonstrate the potential for the discovery of novel bioactive metabolites from actinomycetes isolated from Atlantic Canadian marine sediments.

  10. Potential incursion of marine sediment inland during storms: the radiological importance of actinides

    Energy Technology Data Exchange (ETDEWEB)

    Wilkins, B.T.; Green, N.; Haslam, I.K. [National Radiological Protection Board, Chilton, Didcot, Oxon (United Kingdom); Huntley, D.A.; Dyer, K.R.; Cavrot, D.; Tooley, M.J. [Institute for Marine Studies, University of Plymouth, Drake Circus, Plymouth PL44 8AA, Devon (United Kingdom); Zong, Y. [Environmental Research Centre, University of Durham, Science Laboratories, Parks Road, Durham (United Kingdom)

    1999-08-01

    An assessment of the possible future incursion of marine sediment inland in Cumbria and Lancashire has been carried out. The assessment indicated that material from the patch of clay and silt offshore from Sellafield would not be readily mobilised and would not be brought ashore during a single-storm event. Several low-lying areas are potentially at risk of flooding as a result of severe storms, but any marine sediment deposited inland would have come from the nearshore zone. The original assessment, published in 1996, was made using measurement data for 1988. The results indicated that, in many cases, external irradiation was the most important contributor to the doses to those involved in clean-up operations and to residents, {sup 137}Cs being the radionuclide of importance. The predicted doses were a small fraction of the principal limit recommended by ICRP for members of the public. In this paper, the dose estimates have been refined using newly available data for 1995. Since 1988, activity concentrations of {sup 137}Cs have declined markedly because of remobilisation from the sediment, but changes in the values of {sup 241}Am and Pu are much less. As a result, the predicted overall doses to the various population groups are lower than those estimated previously, and in many cases actinides have become the radionuclides of importance. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  11. [Dynamics of 95Zr in simulated marine water-sediment-organisms system].

    Science.gov (United States)

    Wang, Chunlin; Shi, Jianjun; Sun, Pingyue; Li, Mingyun

    2003-06-01

    To provide scientific evidence to evaluate the behavior of 95Zr in ocean ecosystem, the dynamic model of the transference, accumulation and disappearance of 95Zr among the simulated marine water, sediment and organisms was investigated using Nassarius semiplicatus and Boleophthalums pectinirostris as experimental stuffs. The result showed that 95Zr(Bq.g-1 or Bq.ml-1) in the marine water was decreased more than 90% in the first 4 h, and then descended gradually. 95Zr in sediment was increased in the peak in 48 h and then declined. The radioactivity percent of 95Zr in the shell and muslce of Nassarius semiplicatus was 68.7% and 31.30% respectively, while the radioactivity percent was 22.80%, 12.64%, 34.82%, 10.31%, 4.48%, 11.55% and 3.71%, respectively in the fill, fin, viscera, skull, skin, vertebra and muscle of Boleophthalmus pectinirostris. Nassarius semiplicatus had a greater concentrating capability of 95Zr than Boleophthalmus pectinirostris. The order of the 95Zr concentration was found to be sediment > Nassarius semiplicatus > water > Boleophthalmus pectinirostris. A dynamic model of closed four-compartment was constructed with exponent function.

  12. Diversity and distribution of fungal communities in the marine sediments of Kongsfjorden, Svalbard (High Arctic)

    Science.gov (United States)

    Zhang, Tao; Fei Wang, Neng; Qin Zhang, Yu; Yu Liu, Hong; Yan Yu, Li

    2015-10-01

    This study assessed the diversity and distribution of fungal communities in eight marine sediments of Kongsfjorden (Svalbard, High Arctic) using 454 pyrosequencing with fungal-specific primers targeting the internal transcribed spacer (ITS) region of the ribosomal rRNA gene. Sedimentary fungal communities showed high diversity with 42,219 reads belonging to 113 operational taxonomic units (OTUs). Of these OTUs, 62 belonged to the Ascomycota, 26 to Basidiomycota, 2 to Chytridiomycota, 1 to Zygomycota, 1 to Glomeromycota, and 21 to unknown fungi. The major known orders included Hypocreales and Saccharomycetales. The common fungal genera were Pichia, Fusarium, Alternaria, and Malassezia. Interestingly, most fungi occurring in these Arctic sediments may originate from the terrestrial habitats and different basins in Kongsfjorden (i.e., inner basin, central basin, and outer basin) harbor different sedimentary fungal communities. These results suggest the existence of diverse fungal communities in the Arctic marine sediments, which may serve as a useful community model for further ecological and evolutionary study of fungi in the Arctic.

  13. HEAVY METAL CONTENTS IN MARINE SEDIMENTS AND SEAWATER AT TOTOK BAY AREA, NORTH SULAWESI

    Directory of Open Access Journals (Sweden)

    Delyuzar Ilahude

    2017-07-01

    Full Text Available The study area is located in north-eastern part of Tomini Bay, approximately 80 km south of Manado city, North Sulawesi. This area is closed to submarine tailing disposal system in Buyat Bay. Five marine sediment samples and four water samples from seawater and dig wells have been used for heavy metals (Hg, As, CN analyses by using Atomic Absorption Spectrometry (AAS. This study is a part of research conducted by Marine Geological Institute of Indonesia on morphological changes of seabed in the Totok Bay. The result shows that concentration of mercury (Hg in water samples taken from Ratatotok estuary is higher than standards stipulated Government Regulation (Peraturan Pemerintah/PP No. 82/2001. Meanwhile, concentration of arsenic (As is almost reaching its standard threshold, and conversely cyanide (CN concentration is low. This value of mercury (Hg concentration taken from Ratatotok estuary is much higher than water samples from of Buyat Bay estuary. Significant concentration of mercury (Hg analysed from those particular sampling sites indicated high mercury contamination. Therefore, further examination on ground water of dig wells is necessary, especially for mercury analysis (Hg. Furthermore, comparing the formerly obtained data of mercury concentration in the sediment, this particular study concludes that the sediments in the Totok Bay had contaminated by mercury from gold-processing of illegal mining.

  14. The Surface of Venus is Saturated With Ancient Impact Structures, and its Plains are Marine Sediments

    Science.gov (United States)

    Hamilton, W. B.

    2009-05-01

    Conventional interpretations of Venus are forced to fit dubious pre-Magellan conjectures that the planet is as active internally as Earth and preserves no ancient surface features. Plate tectonics obviously does not operate, so it is commonly assumed that the surface must record other endogenic processes, mostly unique to Venus. Imaginative systems of hundreds of tiny to huge rising and sinking plumes and diapirs are invoked. That much of the surface in fact is saturated with overlapping large circular depressions with the morphology of impact structures is obscured by postulating plume origins for selected structures and disregarding the rest. Typical structures are rimmed circular depressions, often multiring, with lobate debris aprons; central peaks are common. Marine-sedimentation features are overlooked because dogma deems the plains to be basalt flows despite their lack of source volcanoes and fissures. The unearthly close correlation between geoid and topography at long to moderate wavelengths requires, in conventional terms, dynamic maintenance of topography by up and down plumes of long-sustained precise shapes and buoyancy. A venusian upper mantle much stronger than that of Earth, because it is cooler or poorer in volatiles, is not considered. (The unearthly large so-called volcanoes and tessera plateaus often are related to rimmed circular depressions and likely are products of impact fluidization and melting.) Plains-saturating impact structures (mostly more obvious in altimetry than backscatter) with diameters of hundreds of km are superimposed as cookie-cutter bites, are variably smoothed and smeared by apparent submarine impact and erosion, and are differentially buried by sediments compacted into them. Marine- sedimentation evidence includes this compaction; long sinuous channels and distributaries with turbidite- channel characteristics and turbidite-like lobate flows (Jones and Pickering, JGSL 2003); radar-smooth surfaces and laminated aspect in

  15. Distribution and environmental impacts of metals and natural radionuclides in marine sediments in-front of different wadies mouth along the Egyptian Red Sea Coast.

    Science.gov (United States)

    el-Taher, A; Madkour, H A

    2011-02-01

    Forty-four marine sediment samples were collected in-front of wadis mouth along the Egyptian Red Sea coast: Wadi El-Hamra, Wadi El-Esh, Wadi Abu-Shaar, Wadi El-Gemal and Wadi Khashir (Hamata). Several investigations of natural activity and trace metals of surface sediments were carried out. Distributions of naturally occurring radioactive materials (NORM) of (226)Ra, (232)Th and (40)K in the marine sediments were determined using NaI (Tl) γ-ray spectrometry. The average activities (range) of natural radionuclides in all wadis in the studied areas are 27.38 (18-48) Bq kg(-1) for (226)Ra, 38.45 (34-110) Bq kg(-1) for (232)Th and 419.4 (214-641) Bq kg(-1) for (40)K. These results are in agreement with earlier reported data. A comparison of radionuclide activities in the sediment of the studied areas and in other coastal and aquatic environments is given. The radiation hazard parameters (absorbed dose rate, radium equivalent activity and external hazard index) are calculated and compared with the reported data. The results of measurements will serve as base line data and background reference level for Egyptian coastlines.

  16. Distribution and environmental impacts of metals and natural radionuclides in marine sediments in-front of different wadies mouth along the Egyptian Red Sea Coast

    Energy Technology Data Exchange (ETDEWEB)

    El-Taher, A., E-mail: Atef_Eltaher@hotmail.co [Physics Department, Faculty of Science, Al-Azher University, Assuit Branch, 71542 Assuit (Egypt); Madkour, H.A. [National Institute of Oceanography and Fisheries, Red Sea Branch (Egypt)

    2011-02-15

    Forty-four marine sediment samples were collected in-front of wadis mouth along the Egyptian Red Sea coast: Wadi El-Hamra, Wadi El-Esh, Wadi Abu-Shaar, Wadi El-Gemal and Wadi Khashir (Hamata). Several investigations of natural activity and trace metals of surface sediments were carried out. Distributions of naturally occurring radioactive materials (NORM) of {sup 226}Ra, {sup 232}Th and {sup 40}K in the marine sediments were determined using NaI (Tl) {gamma}-ray spectrometry. The average activities (range) of natural radionuclides in all wadis in the studied areas are 27.38 (18-48) Bq kg{sup -1} for {sup 226}Ra, 38.45 (34-110) Bq kg{sup -1} for {sup 232}Th and 419.4 (214-641) Bq kg{sup -1} for {sup 40}K. These results are in agreement with earlier reported data. A comparison of radionuclide activities in the sediment of the studied areas and in other coastal and aquatic environments is given. The radiation hazard parameters (absorbed dose rate, radium equivalent activity and external hazard index) are calculated and compared with the reported data. The results of measurements will serve as base line data and background reference level for Egyptian coastlines.

  17. Measurement and reduction of porewater ammonia in 10-day sediment toxicity tests with marine amphipods

    Energy Technology Data Exchange (ETDEWEB)

    Kohn, N.P.; Karls, R.K.; Barrows, M.E. [Battelle/Marine Sciences Lab., Sequim, WA (United States)

    1994-12-31

    Ammonia is recognized as a potential contributor to amphipod toxicity in sediment bioassays, such as those required for dredged material testing. Measurement of ammonia in sediment porewater prior to testing and monitoring of ammonia during testing have not been routinely performed. The U.S. Environmental Protection Agency (EPA) and U.S. Army Corps of Engineers (USACE) have recently provided guidance for reducing sediment porewater ammonia by aeration and by exchange of overlying water prior to introducing test animals. In this study, two amphipod species, Rhepoxynius abronius and Eohaustorius estuarius, were exposed to eight sediment treatments in 10-day solid-phase static bioassays. Ammonia in sediment porewater was measured prior to testing; treatments with > 70 mg/L total ammonia were manipulated to reduce porewater ammonia in the test chambers to {<=}30 mg/L, following procedures in a memorandum by EPA and USACE. Porewater ammonia was also measured {approximately}24 h after test set up (when animals would normally be added), each day of manipulation before animals were added, and also on Days 5 and 9 for the E. estuarius test. The treatment with the highest porewater ammonia concentration was tested with and without manipulation. Reduction of porewater ammonia required up to 2 days. Toxicity was reduced in the manipulated sediments, but was statistically significant relative to control and reference treatments.

  18. Carbonate preservation in marine sediments: Mid to higher latitude quantitative proxies

    Science.gov (United States)

    Loubere, Paul; Chellappa, Rebecca

    2008-03-01

    Observations of carbonate preservation in marine sediments have long been used to infer changes in ocean circulation or biogenic production. When combined with measures of organic carbon rain and calcite accumulation rates, quantitative estimates of changes in preservation can reveal variation in biogenic fluxes, the org. C to calcite flux ratio and saturation state of bottom waters. Here we develop quantitative dissolution proxies for mid to higher latitudes based on foraminiferal test fragmentation. Examining surface sediments, we find that fragmentation in G. bulloides and G. truncatulinoides is linear with increasing seabed dissolution rate and can be used to quantify changes in carbonate preservation. G. truncatulinoides shows a constant relationship of fragmentation to dissolution. However, we observe that, although linear to dissolution rate, the fragmentation in G. bulloides depends on which morphotype is present. Other species, such as G. inflata, have complex responses to increasing dissolution and are less direct preservation indicators.

  19. Reactivity and fate of secondary alkane sulfonates (SAS) in marine sediments.

    Science.gov (United States)

    Baena-Nogueras, Rosa María; Rojas-Ojeda, Patricia; Sanz, José Luis; González-Mazo, Eduardo; Lara-Martín, Pablo A

    2014-06-01

    This research is focused on secondary alkane sulfonates (SAS), anionic surfactants widely used in household applications that access aquatic environments mainly via sewage discharges. We studied their sorption capacity and anaerobic degradation in marine sediments, providing the first data available on this topic. SAS partition coefficients increased towards those homologues having longer alkyl chains (from up to 141 L kg(-1) for C14 to up to 1753 L kg(-1) for C17), which were those less susceptible to undergo biodegradation. Overall, SAS removal percentages reached up to 98% after 166 days of incubation using anoxic sediments. The degradation pathway consisted on the formation of sulfocarboxylic acids after an initial fumarate attack of the alkyl chain and successive β-oxidations. This is the first study showing that SAS can be degraded in absence of oxygen, so this new information should be taken into account for future environmental risk assessments on these chemicals.

  20. Stratigraphy and Glacial-Marine Sediments of the Amerasian Basin, Central Arctic Ocean.

    Science.gov (United States)

    1981-02-01

    particles and conducting an electronic si/C analisis of the material that passed through the sieve A, using a I A 11 Coulter counter. I he (oulter...Ocean mechanists. Normal pelagic and glacially dericd fine matelital are glacial-marine sediment should he viewed as a complex process distributed...meatn prain si/(i \\;ei iiade heisseri iis ri r it( f xindil atrca fac sedimencrt I\\. PCs at h Ii 05 0-1irf~ifr I. live) 11it11%~ iisr I tii basic

  1. Some Free-Living Heterotrophic Flagellates from Marine Sediments of Tropical Australia

    Science.gov (United States)

    Je Lee, Won

    2006-06-01

    The diversity of heterotrophic flagellates was examined at marine sediments around Cape Tribulation, Australia. The species described belong to the Alveolates, Apusomonadidae, Cercomonadida, Choanoflagellida, Cry ptomonadida, Diplomonadida, Euglenozoa incertae sedis, Kathablepharidae, Kinetoplastida, Pedinellids, Stephanopogonidae, Stramenopiles, Stramenopiles incertae sedis, Thaumatomonadidae and Protista incertae sedis. Among the 51 species from 38 genera encountered in this study is one new taxon: Glissandra similis n. sp., and two new names are introduced: Goniomonas abrupta (Skvortzov 1924) nomen nodum and Cercomonas skvortzovi (Skvortzov 1977) nomen nodum. There was little evidence for endemism because most flagellates including one new taxon described here have been reported.

  2. Impact of Ibrahim River on the spatial variation of coastal marine sediment characteristics

    Science.gov (United States)

    Ghsoub, Myriam; Fakhri, Milad; Courp, Thierry; Khalaf, Gaby; Buscail, Roselyne; Ludwig, Wolfgang

    2017-04-01

    In the aim to evaluate the impact of Ibrahim River on the environmental status of its coastal marine zone, sedimentological (grain size composition), geochemical (organic carbon, total nitrogen, total carbon, organic matter, calcium carbonate, organic and inorganic phosphate) biochemical (chlorophyll-a, pheopigments) and biological parameters (macro-invertebrates) of the sediment were analyzed and interpreted. Three sampling campaigns were executed using the scientific vessel CANA-CNRS on 26-4-2016, 20-6-2016 and 29-7-2016 successively. The samples were collected according to a middle horizontal transectat three different depths (10, 20, and 30 m).The grain size composition of the sediment was mainly composed of fine sand. The obtained values of organic matter ranged between 32 and 54 mg/g. The total nitrogen was between 0.006 and 0.014%. The percentage of calcium carbonate fluctuated between 20 and 30%. This situation may be attributed to the decomposition and the sinking of the shells and some aquatic organism such as Coccolithophores, foraminifers, gastropods and bivalves. Calcium carbonate may also have terrestrial origin related to the carbonated adjacent land and may be exported to the coastal area with the river inputs. The sediment of the studied area was richer in pheopigments (between 0.8 and 3 μg/g) than in chlorophyll-a (less than 0.4 μg/g) witnessing the presence of degraded material due to the high hydrodynamic conditions. Furthermore, the low values of chlorophyll-a witnessed the oligotrophy of the zone. The concentrations of total phosphate ranged between 97 and 148 μg/g. The dominance of the inorganic phosphate at all sampling points indicates that phosphorus is available for the producers, and that the studied area is less contaminated with anthropogenic discharges. This research project reveals the presence of gastropods, crustaceans and some polychaetes along the five studied stations. These groups are generally found in sandy bottoms

  3. 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...... coupling of the terminal oxidation to fermentation. We exposed marine sediments to extreme temperature perturbations to study the nature and robustness of this coupling. Bacterial sulfate reduction and its dependence on fermentation were studied experimentally over a broad temperature range of -0.3 to 40...... optimum temperature was higher and did not change with incubation time. Up to a critical temperature, the concentrations of VFA remained low, acetate and

  4. 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...

  5. 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

    The numbers of sulfate reducers in two Arctic sediments within situ temperatures of 2.6 and -1.7 degrees C were determined. Most-probable-number counts were higher at 10 degrees C than at 20 degrees C, indicating the predominance of a psychrophilic community. Mean specific sulfate reduction rates...... 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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Knoblauch, C.; Joergensen, B.B.; Harder, J.

    1999-09-01

    The numbers of sulfate reducers in two Arctic sediments with in situ temperatures of 2.6 and {minus}1.7C were determined. Most-probable-number counts were higher at 10 C than at 20 C, indicating the predominance of a psychrophilic community. Mean specific sulfate reduction rates 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 their mesophilic counterparts at similarly low temperatures.

  7. Spatiotemporal distributions of Fukushima-derived radionuclides in nearby marine surface sediments

    Directory of Open Access Journals (Sweden)

    M. Kusakabe

    2013-07-01

    Full Text Available Spatiotemporal distributions of anthropogenic radionuclides in marine surface sediments off Miyagi, Fukushima, and Ibaraki Prefectures were analyzed on the basis of data collected during the monitoring program launched by the Japanese Ministry of Education, Sports, Science and Technology in 2011 right after the Fukushima Dai-ichi Nuclear Power Plant accident began. Concentrations of 137Cs in the surface sediments varied spatially by two orders of magnitude, from 1.7 to 580 Bq kg-dry−1, and there was no obvious correlation between 137Cs concentration and the proximity of the sampling location to the accident site. The total inventory of 137Cs accumulated in the upper 3 cm of surface sediments in the monitoring area was estimated to be 3.78 × 1013 Bq, that is, 0.1–2% of the total 137Cs flux from the plant to the ocean as a result of the accident (the percentage depends on the model used to estimate the total flux. The spatial variations of 137Cs concentration and inventory depended on two main factors: the 137Cs concentration in the overlying water during the first several months after the accident and the physical characteristics of the sediments (water content and bulk density. The temporal variations of the concentrations of other anthropogenic radionuclides (90Sr, 95Nb, 110 mAg, 125Sb, 129Te, and 129 mTe in the sediments were also investigated. Activity ratios of these nuclides to 137Cs suggest that the nuclides themselves were not homogenized before they were removed from seawater to the sediments.

  8. Acute marine sediment toxicity: a potential new test with the amphipod Gammarus locusta.

    Science.gov (United States)

    Costa, F O; Correia, A D; Costa, M H

    1998-01-01

    Although amphipod toxicity tests have been successfully used in the United States to assess coastal sediment toxicity, few tests have been developed with European species. The authors have been working with the amphipod Gammarus locusta, a widely spread species along European coastal areas that is particularly abundant in the Portuguese Sado estuary. This amphipod fulfills the most important requirements of a test species. It can be easily reproduced in laboratory and it is tolerant to a broad range of sediment types. A series of tests demonstrated its sensitivity to copper and gamma-hexachlorocyclohexane (lindane) in the sediment (LC50 = 6.8 mg Cu/dry kg, 0.9% total volatile solids; LC50 = 60.5 micrograms HCH/dry kg, 2% total volatile solids) and to some heavily contaminated field sediments. After assessment of the species sensitivity to several noncontaminant variables, an experimental protocol was designed to conduct acute sediment toxicity tests that are briefly described. Proposed is a 10-day static toxicity test at 15 degrees C and 33-34/1000 salinity, with laboratory-produced juveniles and mortality as the endpoint. General assay performance is identical to the American Society for Testing and Materials (ASTM) standard for sediment toxicity tests with marine and estuarine amphipods. The results previously obtained revealed a strong potential for this amphipod to be used in toxicological testing. Considering the wide geographic distribution of this species and its amenability for culturing, it may be an alternative or complementary test for ecotoxicological studies in other European coastal systems where the existing tests cannot be applied or do not offer a definitive solution.

  9. Applications of dendrochronology and sediment geochronology to establish reference episodes for evaluations of environmental radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, W.J.; Carroll, J.; Abraham, J.D.; Landeen, D.S. [Roy F. Weston, Inc., U.S. Department of Energy, Grand Junction Office, 2597 B 3/4 Road, Grand Junction, CO 81503 (United States)

    1998-12-01

    Dendrochronology and sediment geochronology have been used to demonstrate retrospective monitoring of environmental radioactivity at United States Department of Energy (DOE) sites. {sup 14}C in annual growth rings of sagebrush preserved the temporal and spatial patterns of {sup 14}C resulting from dispersion downwind of a nuclear fuel processing facility at the Hanford Site in Washington State. As far as 10 km downwind of the facility, {sup 14}C concentrations were significantly higher in growth rings formed during a fuel processing episode than in rings produced during preoperational or postoperational episodes. An episode of uranium mill tailings deposition in pond sediments at the Grand Junction Office in Colorado was reconstructed using {sup 210}Pb geochronology constrained by a marker of peak {sup 137}Cs fallout. Uranium concentrations in ponds sediments deposited after the processing episode provide a reasonable cleanup standard. These reference episodes of environmental radioactivity reconstructed from measurements taken within contaminated environments can improve or replace reference area data as baseline information for dose reconstructions, risk assessments, and the establishment of cleanup standards. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  10. Teledetection passive et processus decisionnel a reference spatiale: Application a l'aquaculture en milieu marin

    Science.gov (United States)

    Habbane, Mohamed

    L'objectif de cette etude est d'elaborer un processus decisionnel a reference spatiale (PDRS) pour la mariculture. Le PDRS est applique aux eaux cotieres de la baie des Chaleurs, dans le golfe du Saint-Laurent (Canada). Une carte preliminaire regionale d'indices du potentiel maricole, d'une limite de resolution spatiale de 1 kmsp2, est produite avec des parametres du niveau 1. Ces parametres englobent la temperature de l'eau de surface, extraite des images AVHRR, la salinite, les courants ainsi que les pigments chlorophylliens, quantifies a l'aide de mesures in situ. Les images AVHRR, prises en 1994, ont ete utiliees comme reference primaire pour selectionner des aires pouvant supporter une activite maricole sur la cote nord de la baie des Chaleurs. La temperature de surface extraite de ces images permet une analyse mesoechelle a la fois qualitative et quantitative des processus cotiers observes pendant la periode d'acquisition des donnees. Les autres donnees, soit la salinite, les courants et les concentrations en pigments chlorophylliens, sont analysees de facon a identifier la variabilite spatio-temporelle des caracteristiques des eaux de surface. L'ensemble des informations permet de produire une carte preliminaire regionale d'indices du potentiel maricole de la partie centrale de la baie des Chaleurs. Selon cet indice (defini entre 0 et 1), le secteur de potentiel aquicole de 0,5 a 0,75 s'etend sur une superficie d'environ 300 kmsp2. La localisation de cette aire potentielle est en accord avec les fortes concentrations en pigments chlrophylliens, presentant des conditions environnementales ideales a une haute productivite biologique. Par la suite la carte preliminaire est modifiee en tenant compte des parametres du niveau 2. Ces parametres sont la geomorphologie littorale, la bathymetrie, les sediments en suspension, les vents, les vagues, le debit d'eau douce, la glace marine, le carbone organique dissous, les aires de peche et les sources de pollution. Ces

  11. 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.

  12. 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.

  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. In-situ Phytoremediation of PAH and PCB Contaminated Marine Sediments with Eelgrass (Zostera marina)

    Energy Technology Data Exchange (ETDEWEB)

    Huesemann, Michael H.; Hausmann, Tom S.; Fortman, Timothy J.; Thom, Ronald M.; Cullinan, Valerie I.

    2009-10-01

    In view of the fact that there are presently no cost-effective in-situ treatment technologies for contaminated sediments, a 60 week long phytoremediation feasibility study was conducted in seawater-supplied outdoor ponds to determine whether eelgrass (Zostera marina) is capable of removing polynuclear aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) from submerged marine sediments. It was determined that all PAHs and PCBs, independent of the number of aromatic rings and degree of chlorination, respectively, were removed to a much larger extent in planted sediments compared to unplanted controls. After 60 weeks of treatment, the concentration of total PAHs decreased by 73% in planted sediments but only 25% in unplanted controls. Similarly, total PCBs declined by 60% in the presence of plants while none were removed in the unplanted sediment. Overall, PAH and PCB biodegradation was greatest in the sediment layer that contained most of the eelgrass roots. Abiotic desorption tests conducted at week 32 confirmed that the phytoremediation process was not controlled by mass-transfer or bioavailability limitations since all PAHs and PCBs desorbed rapidly and to a large extent from the sediment. PAHs were detected in both roots and shoots, with root and shoot bioaccumulation factors for total PAHs amounting to approximately 3 and 1, respectively, after 60 weeks of phytoremediation treatment. Similarly, the root bioccumulation factor for total PCBs was around 4, while no PCBs were detected in the eelgrass leaves at the end of the experiment. The total mass fraction of PAHs and PCBs absorbed and translocated by plant biomass during the 60 week period was insignificant, amounting to less than 0.5% of the total mass of PAHs and PCBs which was initially present in the sediment. Finally, the number of total heterotrophic bacteria and hydrocarbon degraders was slightly but not statistically significantly greater in planted sediments than in unplanted controls

  15. 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

  16. 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

  17. Biodegradation and mineralization of isotopically labeled TNT and RDX in anaerobic marine sediments.

    Science.gov (United States)

    Ariyarathna, Thivanka; Vlahos, Penny; Smith, Richard W; Fallis, Stephen; Groshens, Thomas; Tobias, Craig

    2017-05-01

    The lack of knowledge on the fate of explosive compounds 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), particularly in marine ecosystems, constrains the application of bioremediation techniques in explosive-contaminated coastal sites. The authors present a comparative study on anaerobic biodegradation and mineralization of (15) N-nitro group isotopically labeled TNT and RDX in organic carbon-rich, fine-grained marine sediment with native microbial assemblages. Separate sediment slurry experiments were carried out for TNT and RDX at 23°C for 16 d. Dissolved and sediment-sorbed fractions of parent and transformation products, isotopic compositions of sediment, and mineralization products of the dissolved inorganic N pool ((15) NH4(+) ,(15) NO3(-) ,(15) NO2(-) , and (15) N2 ) were measured. The rate of TNT removal from the aqueous phase was faster (0.75 h(-1) ) than that of RDX (0.37 h(-1) ), and (15) N accumulation in sediment was higher in the TNT (13%) than the RDX (2%) microcosms. Mono-amino-dinitrotoluenes were identified as intermediate biodegradation products of TNT. Two percent of the total spiked TNT-N is mineralized to dissolved inorganic N through 2 different pathways: denitration as well as deamination and formation of NH4(+) , facilitated by iron and sulfate reducing bacteria in the sediments. The majority of the spiked TNT-N (85%) is in unidentified pools by day 16. Hexahydro-1,3,5-trinitro-1,3,5-triazine (10%) biodegrades to nitroso derivatives, whereas 13% of RDX-N in nitro groups is mineralized to dissolved inorganic N anaerobically by the end of the experiment. The primary identified mineralization end product of RDX (40%) is NH4(+) , generated through either deamination or mono-denitration, followed by ring breakdown. A reasonable production of N2 gas (13%) was seen in the RDX system but not in the TNT system. Sixty-eight percent of the total spiked RDX-N is in an unidentified pool by day 16 and may include

  18. New procedure for recovering extra- and intracellular DNA from marine sediment samples

    Science.gov (United States)

    Alawi, M.; Kallmeyer, J.

    2012-12-01

    Extracellular DNA (eDNA) is a ubiquitous biological compound in aquatic sediment and soil. Despite major methodological advances, analysis of DNA from sediment is still technically challenging, not just because of the co-elution of inhibitory substances, but also due to co-elution of extracellular DNA, which potentially leads to an overestimate of the actual diversity. Previous studies suggested that eDNA might play an important role in biogeochemical element cycling, horizontal gene transfer and stabilization of biofilm structures. Several protocols based on the precipitation of eDNA e.g. with CTAB and ethanol have already been published. However, using these methods we did not succeed in quantifying very low amounts of eDNA (e.g. PCR can be performed. To evaluate the new extraction method two sediments with rather opposing composition were analyzed. Sediment from the South Pacific Gyre, the most oligotrophic oceanic region on earth and organic-rich Baltic Sea sediment (Northern Germany) were processed. Using this new procedure high purity genomic iDNA and eDNA with a molecular size range between 20 bp and 50k bp can be simultaneously recovered even from very oligotrophic sediment with very low cell abundances. The main fraction of recovered eDNA was suitable for downstream applications like PCR and had a molecular size that indicates minimal shearing. Despite about two decades of research many questions about deep subsurface life remain unanswered. The fact that microbes can be found even in deep oligotrophic marine sediment raises the fundamental questions of the types and availability of substrates and their biogeochemical cycling. This is the first study that provides evidence that eDNA is an important potential substrate for microorganisms in the deep biosphere. Also, our results show a link between cell counts and eDNA content, indicating that the eDNA pool in the investigated sediment consist mainly of microbial DNA. Comparative sequence analysis of

  19. The influence of sedimentation rate variation on the occurrence of methane hydrate crystallized from dissolved methane in marine gas hydrate system

    Science.gov (United States)

    Yuncheng, C.; Chen, D.

    2015-12-01

    Methane is commonly delivered to the gas hydrate stability zone by advection of methane-bearing fluids, diffusion of dissolved methane, and in-situ biogenic methane production (Davie and Buffett, 2003), except at cold vent sites. Burial of pore water and sediment compaction can induce the fluid flux change (Bhatnagar et al., 2007). Sedimentation supply the organic material for methane production. In addition, Gas hydrate can move to below gas hydrate stability zone and decompose via sedimentation. Therefore, sedimentation significantly affect the gas hydrate accumulation. ODP site 997 located at the Blake Ridge. The sedimentation rate is estimated to 48 m/Ma, 245m/Ma, 17.2 m/Ma and 281m/Ma for 0-2.5Ma, 2.5-3.75Ma, 3.75-4.4Ma, and 4.4-5.9Ma, respectively, according to the age-depth profile of biostratigraphic marker of nonnofossils(Paull et al., 1996). We constructed a gas hydrate formation model and apply to ODP sites 997 to evaluate the influence of variation of sedimentation rate on gas hydrate accumulation. Our results show that the gas hydrate format rate varied from 0.013mol/m2-a to 0.017mol/m2-a and the gas hydrate burial to below gas hydrate stability zone varied from 0.001mol/m2-a to 0.018mol/m2-a during recently 5Ma. The gas hydrate formation rate by pore water advection and dissolved methane diffusion would be lower, and the top occurrence of gas hydrate would be shallower, when the sedimentation rate is higher. With higher sedimentation rate, the amount of gas hydrate burial to below stability zone would be larger. The relative high sedimentation rate before 2.5 Ma at ODP site 997 produced the gas hydrate saturation much lower than present value, and over 60% of present gas hydrates are formed during recent 2.5Ma. Reference: Bhatnagar,G., Chapman, W. G.,Dickens, G. R., et al. Generalization of gas hydrate distribution and saturation in marine sediments by scaling of thermodynamic and transport processes. American Journal of Science, 2007, 307, 861

  20. 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.

  1. Diversity and bioprospecting of culturable actinomycetes from marine sediment of the Yellow Sea, China.

    Science.gov (United States)

    Xiong, Zhi-Qiang; Liu, Qiao-Xia; Pan, Zhao-Long; Zhao, Na; Feng, Zhi-Xiang; Wang, Yong

    2015-03-01

    Marine actinomycetes are a potential source of a wide variety of bioactive natural products. In this work, seven pretreatments, three selective isolation media, and five artificial seawater concentrations were used to isolate actinomycetes from the sediments collected from Yellow Sea, China. Statistical analysis showed that only the isolation medium strongly affected the total and bioactive numbers of actinomycete isolates. A total of 613 actinobacterial strains were isolated and screened for antimicrobial activities; 154 isolates showed activity against at least one of nine test drug-resistant microorganisms. Eighty-nine representatives with strong antimicrobial activity were identified phylogenetically based on 16S rRNA gene sequencing, which were assigned to five different actinomycete genera Streptomyces, Kocuria, Saccharomonospora, Micromonospora, and Nocardiopsis. Using PCR-based screening for six biosynthetic genes of secondary metabolites, all 45 isolates with acute activity have at least one biosynthetic gene, 28.8 % of which possess more than three biosynthetic genes. As a case, strain SMA-1 was selected for antimicrobial natural product discovery. Three diketopiperazine dimers including a new compound iso-naseseazine B (1) and two known compounds naseseazine B (2) and aspergilazine A (3) were isolated by bioassay-guided separation. These results suggested that actinomycetes from marine sediments are a potential resource of novel secondary metabolites and drugs.

  2. 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)

  3. Marine Mammal Brucella Reference Strains Are Attenuated in a BALB/c Mouse Model.

    Science.gov (United States)

    Nymo, Ingebjørg H; Arias, Maykel A; Pardo, Julián; Álvarez, María Pilar; Alcaraz, Ana; Godfroid, Jacques; Jiménez de Bagüés, María Pilar

    2016-01-01

    Brucellosis is a zoonosis of worldwide distribution with numerous animal host species. Since the novel isolation of Brucella spp. from marine mammals in 1994 the bacteria have been isolated from various marine mammal hosts. The marine mammal reference strains Brucella pinnipedialis 12890 (harbour seal, Phoca vitulina) and Brucella ceti 12891 (harbour porpoise, Phocoena phocoena) were included in genus Brucella in 2007, however, their pathogenicity in the mouse model is pending. Herein this is evaluated in BALB/c mice with Brucella suis 1330 as a control. Both marine mammal strains were attenuated, however, B. ceti was present at higher levels than B. pinnipedialis in blood, spleen and liver throughout the infection, in addition B. suis and B. ceti were isolated from brains and faeces at times with high levels of bacteraemia. In B. suis-infected mice serum cytokines peaked at day 7. In B. pinnipedialis-infected mice, levels were similar, but peaked predominantly at day 3 and an earlier peak in spleen weight likewise implied an earlier response. The inflammatory response induced pathology in the spleen and liver. In B. ceti-infected mice, most serum cytokine levels were comparable to those in uninfected mice, consistent with a limited inflammatory response, which also was indicated by restricted spleen and liver pathology. Specific immune responses against all three strains were detected in vitro after stimulation of splenocytes from infected mice with the homologous heat-killed brucellae. Antibody responses in vivo were also induced by the three brucellae. The immunological pattern of B. ceti in combination with persistence in organs and limited pathology has heretofore not been described for other brucellae. These two marine mammal wildtype strains show an attenuated pattern in BALB/c mice only previously described for Brucella neotomea.

  4. Marine Mammal Brucella Reference Strains Are Attenuated in a BALB/c Mouse Model

    Science.gov (United States)

    Nymo, Ingebjørg H.; Arias, Maykel A.; Pardo, Julián; Álvarez, María Pilar; Alcaraz, Ana; Godfroid, Jacques; Jiménez de Bagüés, María Pilar

    2016-01-01

    Brucellosis is a zoonosis of worldwide distribution with numerous animal host species. Since the novel isolation of Brucella spp. from marine mammals in 1994 the bacteria have been isolated from various marine mammal hosts. The marine mammal reference strains Brucella pinnipedialis 12890 (harbour seal, Phoca vitulina) and Brucella ceti 12891 (harbour porpoise, Phocoena phocoena) were included in genus Brucella in 2007, however, their pathogenicity in the mouse model is pending. Herein this is evaluated in BALB/c mice with Brucella suis 1330 as a control. Both marine mammal strains were attenuated, however, B. ceti was present at higher levels than B. pinnipedialis in blood, spleen and liver throughout the infection, in addition B. suis and B. ceti were isolated from brains and faeces at times with high levels of bacteraemia. In B. suis-infected mice serum cytokines peaked at day 7. In B. pinnipedialis-infected mice, levels were similar, but peaked predominantly at day 3 and an earlier peak in spleen weight likewise implied an earlier response. The inflammatory response induced pathology in the spleen and liver. In B. ceti-infected mice, most serum cytokine levels were comparable to those in uninfected mice, consistent with a limited inflammatory response, which also was indicated by restricted spleen and liver pathology. Specific immune responses against all three strains were detected in vitro after stimulation of splenocytes from infected mice with the homologous heat-killed brucellae. Antibody responses in vivo were also induced by the three brucellae. The immunological pattern of B. ceti in combination with persistence in organs and limited pathology has heretofore not been described for other brucellae. These two marine mammal wildtype strains show an attenuated pattern in BALB/c mice only previously described for Brucella neotomea. PMID:26959235

  5. 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

  6. 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

  7. Morphology and Sediment Transport Dynamics of a Trough-Blowout Dune, Bodega Marine Reserve, Northern California

    Science.gov (United States)

    Jorgenson, D.; Dunleavy, C. J.; Smith, M. E.

    2014-12-01

    Blowout dunes are a primary mechanism for transporting sand within vegetated coastal dune systems. Understanding the fine-scale variation in sediment transport within these systems is critical to predicting their formation and migration. Previous investigations of a coastal dune system located at the Bodega Marine Reserve, on the Sonoma Coast of Northern California have indicated that aeolian sand flux in unvegetated sand is ~450x greater than in vegetated areas. To better understand sand flux and its relationship with wind speed, direction and precipitation, we deployed an array of 12 sand traps within a single blowout area adjacent to the BOON marine climatology station. The blowout is trough- shaped, approximately 50 meters long and 15 meters wide. Its main 'fairway' is 5-10 meters below the surrounding beach grass (Ammophila)-covered land surface. Surface sediment within the blowout is fine-grained to granule-sized lithic to sub-lithic sand, and is coarsest in the center. Dune sediment in the Bodega Marine Reserve has been transported by aeolian processes from Salmon Creek Beach to the NW. Within the blowout, typical bedforms include 15-25 cm-wavelength, ~10 cm high sinuous to lingoid ripples arranged perpendicularly to the dominant wind direction (~280 degrees). An 8-10 meter-high mound at the downwind end has accumulated due to the trapping of sand flux by vegetation. Sediment flux across the studied blowout was sampled monthly over a 10-month period of 2013-2014. Sand traps were constructed using modified PVC cylinders, and are 0.5 meter high and 0.3 meter in diameter, with a 0.74-micron mesh screen. Based on measured sand flux, the sites can be categorized into three groups-axial, medial, and peripheral. Rates increase downwind within the blowout. Inter-site sand flux variability within unvegetated locations of the blowout is greater than two orders of magnitude. Axial sites, which experience the greatest sand flux, occur on the edge of the blowout adjacent

  8. Microarray-based characterization of microbial community functional structure and heterogeneity in marine sediments from the Gulf of Mexico.

    Science.gov (United States)

    Wu, Liyou; Kellogg, Laurie; Devol, Allan H; Tiedje, James M; Zhou, Jizhong

    2008-07-01

    Marine sediments of coastal margins are important sites of carbon sequestration and nitrogen cycling. To determine the metabolic potential and structure of marine sediment microbial communities, two cores were collected each from the two stations (GMT at a depth of 200 m and GMS at 800 m) in the Gulf of Mexico, and six subsamples representing different depths were analyzed from each of these two cores using functional gene arrays containing approximately 2,000 probes targeting genes involved in carbon fixation; organic carbon degradation; contaminant degradation; metal resistance; and nitrogen, sulfur, and phosphorous cycling. The geochemistry was highly variable for the sediments based on both site and depth. A total of 930 (47.1%) probes belonging to various functional gene categories showed significant hybridization with at least 1 of the 12 samples. The overall functional gene diversity of the samples from shallow depths was in general lower than those from deep depths at both stations. Also high microbial heterogeneity existed in these marine sediments. In general, the microbial community structure was more similar when the samples were spatially closer. The number of unique genes at GMT increased with depth, from 1.7% at 0.75 cm to 18.9% at 25 cm. The same trend occurred at GMS, from 1.2% at 0.25 cm to 15.2% at 16 cm. In addition, a broad diversity of geochemically important metabolic functional genes related to carbon degradation, nitrification, denitrification, nitrogen fixation, sulfur reduction, phosphorus utilization, contaminant degradation, and metal resistance were observed, implying that marine sediments could play important roles in biogeochemical cycling of carbon, nitrogen, phosphorus, sulfate, and various metals. Finally, the Mantel test revealed significant positive correlations between various specific functional genes and functional processes, and canonical correspondence analysis suggested that sediment depth, PO(4)(3-), NH(4)(+), Mn

  9. Bacterial Diversity, Sediment Age and Organic Respiration in the Marine Sedimentary Environment

    Science.gov (United States)

    Walsh, E. A.; Kirkpatrick, J. B.; Pockalny, R. A.; Sauvage, J.; Sogin, M. L.; D'Hondt, S.

    2014-12-01

    Subseafloor sediment hosts to a large1, taxonomically rich2 and metabolically diverse3 microbial ecosystem. However, the factors that control microbial diversity in subseafloor sediment have rarely been explored. Here we show that subseafloor bacterial richness varies directly with sediment age and net rate of organic-fueled respiration. We examined three open-ocean sites (in the Bering Sea and equatorial Pacific) and one continental margin site (Indian Ocean), with sediment depths to 404 meters below seafloor. At all locations, taxonomic richness decreases exponentially with increasing sediment age. Richness declines most rapidly for a few hundred thousand years after sediment deposition. This profile generally matches the canonical relationship between rates of organic oxidation and sediment age 4. To examine the potential link between organic oxidation and taxonomic richness we used pore-water chemical profiles to quantify net rates of organic respiration at the three open-ocean sites (the chemical profiles of the ocean-margin site are not in diffusive steady state). Taxonomic richness and total rate of organic-fueled respiration are highest at the high productivity Bering Sea site and lower at the moderate productivity equatorial Pacific sites. At each of these sites, organic-fueled respiration rate and taxonomic richness are highest at the surface and decline together as sediment depth and age increase. To our knowledge, this is the first evidence that taxonomic richness is closely linked to organic-fueled respiration rate and sediment age in subseafloor sediment. References1. Kallmeyer, J., Pockalny, R., Adhikari, R. R., Smith, D. C. & D'Hondt, S. Proceedings of the National Academy of Sciences, doi:10.1073/pnas.1203849109 (2012). 2. Inagaki, F. et al. Proceedings of the National Academy of Sciences 103, 2815-2820 (2006). 3. D'Hondt, S. et al. Science 306, 2216-2221, doi:10.1126/science.1101155 (2004). 4. Middelburg, J. J. Geochimica et Cosmochimica Acta 53

  10. The use of fossil benthic foraminifera to define reference conditions for present-day marine waters

    Science.gov (United States)

    Bouchet, V. M. P.; Hess, S.; Dolven, J. K.; Alve, E.

    2012-04-01

    The implementation of legislations is generating a fruitful debate amongst marine scientists about how to define efficient and reliable bio-assessment tools to monitor the ecological quality status (EcoQS) of marine waters. According to those legislations, EcoQS assessment needs a "reference condition" with which to compare the present-day condition at a site. The fossil record has a potential to reconstruct PaleoEcoQS and thereby establish in situ reference conditions from pre-impact times. Unlike most macrofaunal groups which are the most commonly used biological quality indicator in these environments, benthic foraminifera leave a fossil record and therefore allow the reconstruction of human-induced environmental disturbance over decades to centuries. Foraminifera have the potential to serve as ecosystem characterization tools in modern and past marine environments. We compared the response of benthic foraminifera, macrofauna and selected environmental parameters from the same sites in areas with relatively stable salinity and temperature conditions but otherwise contrasting environmental properties (e.g., varying degree of anthropogenic impact). In August 2008, replicate samples for living (stained) benthic foraminifera and macrofauna from 27 stations in 11 silled fjords along the Norwegian Skagerrak coast were examined. Environmental data (bottom-water dissolved-oxygen, TOC, TN and pigments) were analysed for each station. The same kind of data were analysed from 2 recolonisation sites in the inner Oslofjord. In addition, the PaleoEcoQS during the past century was reconstructed using benthic foraminifera and selected environmental parameters from 11 stations in the inner Oslofjord. Results show that living benthic foraminifera are at least as reliable to define present-day EcoQS as conventional methods. Fossil benthic foraminifera can also define ecological status of reference conditions from pre-impacted times. This is not possible using conventional methods

  11. Culturable diversity and antimicrobial activity of Actinobacteria from marine sediments in Valparaíso bay, Chile

    OpenAIRE

    Claverías, Fernanda P.; Undabarrena, Agustina; González, Myriam; Seeger, Michael; Cámara, Beatriz

    2015-01-01

    Marine-derived Actinobacteria are a source of a broad variety of secondary metabolites with diverse biological activities, such as antibiotics and antitumorals; many of which have been developed for clinical use. Rare Actinobacteria represent an untapped source of new bioactive compounds that have been scarcely recognized. In this study, rare Actinobacteria from marine sediments were isolated from the Valparaíso bay, Chile, and their potential to produce antibacterial compounds was evaluated....

  12. 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.

  13. Species sensitivity distributions for suspended clays, sediment burial, and grain size change in the marine environment.

    Science.gov (United States)

    Smit, Mathijs G D; Holthaus, Karlijn I E; Trannum, Hilde C; Neff, Jerry M; Kjeilen-Eilertsen, Grete; Jak, Robbert G; Singsaas, Ivar; Huijbregts, Mark A J; Hendriks, A Jan

    2008-04-01

    Assessment of the environmental risk of discharges, containing both chemicals and suspended solids (e.g., drilling discharges to the marine environment), requires an evaluation of the effects of both toxic and nontoxic pollutants. To date, a structured evaluation scheme that can be used for prognostic risk assessments for nontoxic stress is lacking. In the present study we challenge this lack of information by the development of marine species sensitivity distributions (SSDs) for three nontoxic stressors: suspended clays, burial by sediment, and change in sediment grain size. Through a literature study, effect levels were obtained for suspended clays, as well as for burial of biota. Information on the species preference range for median grain size was used to assess the sensitivity of marine species to changes in grain size. The 50% hazardous concentrations (HC50) for suspended barite and bentonite based on 50% effect concentrations (EC50s) were 3,010 and 1,830 mg/L, respectively. For burial the 50% hazardous level (HL50) was 5.4 cm. For change in median grain size, two SSDs were constructed; one for reducing and one for increasing the median grain size. The HL50 for reducing the median grain size was 17.8 mum. For increasing the median grain size this value was 305 mum. The SSDs have been constructed by using information related to offshore oil- and gas-related activities. Nevertheless, the results of the present study may have broader implications. The hypothesis of the present study is that the SSD methodology developed for the evaluation of toxic stress can also be applied to evaluate nontoxic stressors, facilitating the incorporation of nontoxic stressors in prognostic risk assessment tools.

  14. Optical Dating of Marine Sediment From ODP Core 658B - An Intercomparison With an Independent AMS 14C Chronology

    Science.gov (United States)

    Armitage, S. J.; Stokes, S.; Henderson, G.

    2004-12-01

    We demonstrate the potential of optical dating of detrital quartz silt from marine sediments via a chronological intercomparison for samples from ODP Site 658, which range in age from 0 to 140ka. ODP Site 658 is located off Cap Blanc, Mauritania. It has a high sedimentation rate (18 cm/ka), due to high regional surface productivity and large inputs of windblown Africa dust. This windblown dust provides both the substrate for optical dating and a proxy for North African aridity. The AMS 14C chronology is based on monospecific foraminiferal (Globigerinoides bulloides) samples. This is the first large-scale, systematic application of optical dating to marine sediment, and demonstrates that the technique has considerable potential for the age estimation of otherwise undateable deep-sea material. Optical dating techniques measure the total ionising radiation dose that a mineral grain has received since its last exposure to sunlight (i.e. during burial). The resulting optical age is essentially calibrated via a knowledge of the environmental dose rate, yielding the burial period. The environmental dose rate is derived from the decay of radioisotopes in the sediment (K, U and Th). In terrestrial sediments, the uranium and thorium decay chains can be assumed to be in equilibrium. In the marine realm this assumption is not valid, and unsupported uranium decay series exist on deposition. Consequently, the environmental dose rate changes with sample age. This problem was circumvented by quantifying U and Th decay series disequilibrium, using an MC-ICP-MS. The evolution of the environmental dose rate during burial was modelled, and ages for each sample calculated. The 14C and optical ages are generally in good agreement, indicating that the latter technique can provide equally robust chronologies for marine sediments. Although the maximum age attainable using optical dating is sample specific, the dose rate and luminescence characteristics of the samples analysed in this study

  15. Occurrence of Priming in the Degradation of Lignocellulose in Marine Sediments.

    Directory of Open Access Journals (Sweden)

    Evangelia Gontikaki

    Full Text Available More than 50% of terrestrially-derived organic carbon (terrOC flux from the continents to the ocean is remineralised in the coastal zone despite its perceived high refractivity. The efficient degradation of terrOC in the marine environment could be fuelled by labile marine-derived material, a phenomenon known as "priming effect", but experimental data to confirm this mechanism are lacking. We tested this hypothesis by treating coastal sediments with 13C-lignocellulose, as a proxy for terrOC, with and without addition of unlabelled diatom detritus that served as the priming inducer. The occurrence of priming was assessed by the difference in lignocellulose mineralisation between diatom-amended treatments and controls in aerobic sediment slurries. Priming of lignocellulose degradation was observed only at the initial stages of the experiment (day 7 and coincided with overall high microbial activity as exemplified by total CO2 production. Lignocellulose mineralisation did not differ consistently between diatom treatments and control for the remaining experimental time (days 14-28. Based on this pattern, we hypothesize that the faster initiation of lignocellulose mineralisation in diatom-amended treatments is attributed to the decomposition of accessible polysaccharide components within the lignocellulose complex by activated diatom degraders. The fact that diatom-degraders contributed to lignocellulose degradation was also supported by the different patterns in 13C-enrichment of phospholipid fatty acids between treatments. Although we did not observe differences between treatments in the total quantity of respired lignocellulose at the end of the experiment, differences in timing could be important in natural ecosystems where the amount of time that a certain compound is subject to aerobic degradation before burial to deeper anoxic sediments may be limited.

  16. Study on data integration methods for marine sediment detrital minerals%海底沉积物碎屑矿物数据整合技术研究

    Institute of Scientific and Technical Information of China (English)

    刘志杰; 金秉福; 张瑞端; 余佳; 王昆山; 张欢

    2015-01-01

    海底沉积物碎屑矿物数据是海洋地质领域的重要基础资料,它在海洋沉积作用、环境演变研究以及海底砂矿资源勘探中具有突出的意义.在系统分析了碎屑矿物特征和不同时期碎屑矿物鉴定差异的基础上,探讨了影响碎屑矿物数据整合的主要因素,构建了海底沉积物碎屑矿物数据整合的技术体系,包括碎屑矿物数据格式制定、规范性处理、数据质量控制以及数据重复性检查等方面,提出了3级数据排重模式,并对数据整合的深入开展进行了探讨.该研究成果有利于促进海洋地质工作规范化以及历史调查数据的充分利用,同时也为海底沉积物其他类型资料的整合提供参考.%Detrital mineral data of marine sediments are the important basis information in the marine geological field, and these data have prominent significance in the marine sedimentation, environmental evolution and exploration of submarine placer resources. Based on the systematical analysis of detrital mineral characteristics and differences of identification results in different periods, this paper discussed the major factors affecting detrital mineral data integration and built up a technical system to integrate marine sediment detrital mineral data, including data standard formats, data normalized processing, data quality control and data reproducibility checking, and established a 3-level data de-duplication model. Furthermore, this paper discussed advices to improve the detrital mineral data in future. This study is beneficial to promote the standardization of marine geological work and the full utilization of historical data, and it also provides a reference for the data integration of other marine sediments.

  17. 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

  18. Marine sediments monitoring studies for trace elements with the application of fast temperature programs and solid sampling high resolution continuum source atomic absorption spectrometry

    Science.gov (United States)

    Orani, Anna Maria; Han, Eunmi; Mandjukov, Petko; Vassileva, Emilia

    2015-01-01

    Analytical procedure for the determination of As, Cd, Cu, Ni, Co and Cr in marine sediment samples using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS AAS) and direct solid sample analysis has been developed. The application of fast programs in combination with direct solid sampling allows to eliminate the drying and pretreatment steps, however makes impossible the use of liquid standards for calibration. Iridium treated platforms were applied throughout the present study. Calibration technique based on the use of solid certified reference materials (marine sediments) similar to the nature of the analyzed sample and statistics of regression analysis were applied to the real sediment samples. The instrumental parameters were optimized in order to obtain reproducible and interference free analytical signals. The ISO-17025 requirements and Eurachem guidelines were followed in the validation of the proposed analytical procedure. Accordingly, blanks, selectivity, calibration, linearity, working range, trueness, repeatability reproducibility, limits of detection and quantification and expanded uncertainty (k = 2) for all investigated elements were assessed. Two different approaches for the estimation of measurement uncertainty were applied and obtained results compared. The major contributors to the combined uncertainty of the analyte mass fraction were found to be the homogeneity of the samples and the microbalance precision. The influence of sample particle sizes on the total combined uncertainty was also evaluated. Traceability to SI system of units of the obtained by the proposed analytical procedure results was demonstrated. Additionally, validation of the methodology developed was effectuated by the comparison of the obtained results with independent method e.g. ICP-MS with external calibration. The use of solid sampling HR CS AAS for the determination of trace elements in marine sediment matrix gives significant advantages

  19. Historical Profiles of Polycyclic Aromatic Hydrocarbons (PAHs) in Marine Sediment Cores from Northwest Spain.

    Science.gov (United States)

    Pérez-Fernández, Begoña; Viñas, Lucía; Bargiela, Jesica

    2016-11-01

    The northwest coast of Spain is characterized by an irregular coastline rich in marine life and with the highest mussel production in Europe. Taking this into account, the characterization of the pollution levels and the sources involved appear necessary. Not only were parent Polycyclic Aromatic Hydrocarbons (PAHs) analysed but also their alkylated homologues. In total, 35 compounds were analyzed in 5 sediment cores. Sediments were collected using a box core dredge and extracted by (Pressurized Liquid Extraction) whilst the quantification of PAHs was performed using gas chromatography coupled to mass spectrometry (GC-MS). The total concentration detected varied from 49.6 to 2489 ng g(-1) dry weight (d.w.) of which parent PAHs ranged from 44.5 to 2254 ng g(-1) d.w. and alkylated PAHs varied from 5.04 to 317 ng g(-1) d.w. Temporal and spatial evolution were outlined and pollution sources were identified along with a possible correlation between this pollution and local history and industry. Most of the PAHs from the superficial samples have a biomass and coal combustion profile, and some specific, localized events are reflected in the total PAH concentration evolution. Moreover, the study of the deepest layers of the sampled cores provides a baseline to develop background concentration values that will help in future sediment quality assessment.

  20. 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.

  1. Sensitivity of the marine benthic copepod Tisbe biminiensis (copepoda, harpacticoida to potassium dichromate and sediment particle size

    Directory of Open Access Journals (Sweden)

    Cristiane M. V. Araújo-Castro

    2009-03-01

    Full Text Available For the future use of the marine benthic copepod Tisbe biminiensis in solid-phase sediment toxicological bioassays, the present study investigated the effect of muddy sediment from the Maracaípe estuary (northeastern Brazil, sediment particle size and the reference toxicant potassium dichromate on the species. Muddy sediment from Maracaípe can be used as control sediment, since it does not interfere in the copepod life-cycle and has metal contamination levels that are unlikely to produce any detrimental biological effects on benthic invertebrates. Neither survival nor fecundity was affected by grain size, suggesting that this species can be used with any kind of sediment from muddy to sandy. The sensitivity of T. biminiensis to K2Cr2O7 in acute tests was similar to that of other organisms. The LC50 (lethal concentration to 50% of the test organisms medium values for T. biminiensis were 7.51, 4.68 and 3.19 mg L-1 for Cr in 48, 72 and 96 h, respectively. These results suggest that T. biminiensis is a promising organism for use in solid-phase sediment toxicity assessments.Visando o uso futuro do copépodo marinho bentônico Tisbe biminiensis em bioensaios toxicológicos de sedimentos na fase sólida, o presente estudo investigou o efeito do sedimento lamoso do estuário de Maracaípe (Nordeste do Brasil. Foram considerados a granolometria e o tóxico de referência dicromato de potássio sobre a espécie. O sedimento lamoso de Maracaípe pode ser usado como controle, uma vez que não interfere no ciclo de vida do copépodo e possui níveis de contaminação de metais que não causariam efeitos biológicos em invertebrados bentônicos. Nem a sobrevivência ou fecundidade foi afetada pelo tamanho do grão, sugerindo que esta espécie pode ser usada com qualquer tipo de sedimento, de lama a areia. A sensibilidade de T. biminiensis ao K2Cr2O7 em testes agudos foi similar a de outros organismos. Os valores de CL50 (concentração letal a 50% dos

  2. 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

  3. As, Cd, Cr, Ni and Pb pressurized liquid extraction with acetic acid from marine sediment and soil samples

    Energy Technology Data Exchange (ETDEWEB)

    Moreda-Pineiro, Jorge [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna. Campus da Zapateira s/n. E-15071. A Coruna (Spain)]. E-mail: jmoreda@udc.es; Alonso-Rodriguez, Elia [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna. Campus da Zapateira s/n. E-15071. A Coruna (Spain); Lopez-Mahia, Purificacion [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna. Campus da Zapateira s/n. E-15071. A Coruna (Spain); University Institute of Environment, University of A Coruna, Pazo de Longora, Lians, E-15179. Oleiros (Spain); Muniategui-Lorenzo, Soledad [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna. Campus da Zapateira s/n. E-15071. A Coruna (Spain); Prada-Rodriguez, Dario [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna. Campus da Zapateira s/n. E-15071. A Coruna (Spain); University Institute of Environment, University of A Coruna, Pazo de Longora, Lians, E-15179. Oleiros (Spain); Moreda-Pineiro, Antonio [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n. E-15782, Santiago de Compostela (Spain); Bermejo-Barrera, Adela [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n. E-15782, Santiago de Compostela (Spain); Bermejo-Barrera, Pilar [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n. E-15782, Santiago de Compostela (Spain)

    2006-12-15

    Rapid leaching procedures by Pressurized Liquid Extraction (PLE) have been developed for As, Cd, Cr, Ni and Pb leaching from environmental matrices (marine sediment and soil samples). The Pressurized Liquid Extraction is completed after 16 min. The released elements by acetic acid Pressurized Liquid Extraction have been evaluated by inductively coupled plasma-optical emission spectrometry. The optimum multi-element leaching conditions when using 5.0 ml stainless steel extraction cells, were: acetic acid concentration 8.0 M, extraction temperature 100 deg. C, pressure 1500 psi, static time 5 min, flush solvent 60%, two extraction steps and 0.50 g of diatomaceous earth as dispersing agent (diatomaceous earth mass/sample mass ratio of 2). Results have showed that high acetic acid concentrations and high extraction temperatures increase the metal leaching efficiency. Limits of detection (between 0.12 and 0.5 {mu}g g{sup -1}) and repeatability of the over-all procedure (around 6.0%) were assessed. Finally, accuracy was studied by analyzing PACS-2 (marine sediment), GBW-07409 (soil), IRANT-12-1-07 (cambisol soil) and IRANT-12-1-08 (luvisol soil) certified reference materials (CRMs). These certified reference materials offer certified concentrations ranges between 2.9 and 26.2 {mu}g g{sup -1} for As, from 0.068 to 2.85 {mu}g g{sup -1} for Cd, between 26.4 and 90.7 {mu}g g{sup -1} for Cr, from 9.3 to 40.0 {mu}g g{sup -1} for Ni and between 16.3 and 183.0 {mu}g g{sup -1} for Pb. Recoveries after analysis were between 95.7 and 105.1% for As, 96.2% for Cd, 95.2 and 100.6% for Cr, 95.7 and 103% for Ni and 94.2 and 105.5% for Pb.

  4. An inter-laboratory investigation of the Arctic sea ice biomarker proxy IP25 in marine sediments: key outcomes and recommendations

    Directory of Open Access Journals (Sweden)

    S. T. Belt

    2013-09-01

    comparable using these methods. Recoveries of some more unsaturated HBIs and the internal standard 9-octylheptadecene, however, were lower with the ASE procedure, possibly due to partial degradation of these more reactive chemicals as a result of higher temperatures employed with this method. For future measurements, we recommend the use of reference sediment material with known concentration(s of IP25 for determining and routinely monitoring instrumental response factors. Given the significance placed on the presence (or otherwise of IP25 in marine sediments, some further recommendations pertaining to quality control are made that should also enable the two main anomalies identified here to be addressed.

  5. 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

  6. A review of strategies to monitor water and sediment quality for a sustainability assessment of marine environment.

    Science.gov (United States)

    Tavakoly Sany, Seyedeh Belin; Hashim, Rosli; Rezayi, Majid; Salleh, Aishah; Safari, Omid

    2014-01-01

    The basic aim of this work is (1) to review and present practically operational requirements for a sustainability assessment of marine environment, such as describing the monitoring process, research approaches, objectives, guidelines, and indicators and (2) to illustrate how physico-chemical and biological indicators can be practically applied, to assess water and sediment quality in marine and coastal environment. These indicators should meet defined criteria for practical usefulness, e.g. they should be simple to understand and apply to managers and scientists with different educational backgrounds. This review aimed to encapsulate that variability, recognizing that meaningful guidance should be flexible enough to accommodate the widely differing characteristics of marine ecosystems.

  7. Metal pollution and ecological risk assessment in marine sediments of Karachi Coast, Pakistan.

    Science.gov (United States)

    Mashiatullah, Azhar; Chaudhary, Muhammad Zaman; Ahmad, Nasir; Javed, Tariq; Ghaffar, Abdul

    2013-02-01

    Concentrations of 12 metals (Fe, Mn, Cr, Mo, Ni, Pb, Se, Sr, U, V, Zn, and Zr) in surface sediments of Karachi Coast, Pakistan were determined to evaluate their distribution and pollution assessment. The measured metals in the sediments were found to be in the range of Fe, 0.84-6.96 %; Mn, 300-1,300 μg/g; Cr, 12.0-319.84 μg/g; Mo, 0.49-2.03 μg/g; Ni, 1.53-58.86 μg/g; Pb, 9.0-49.46 μg/g; Se, 0.25-.86 μg/g; Sr, 192-1185 μg/g; U, 0.19-1.66 μg/g; V, 15.80-118.20 μg/g; Zn, 15.60-666.28 μg/g; and Zr, 44.02-175.26 μg/g. The mean contents of the metal studied were: Fe, 3.07 %, Mn, 0.05 %; Cr, 96.75 μg/g; Mo, 1.34 μg/g; Ni, 31.39 μg/g; Pb, 23.24 μg/g; Se, 0.61 μg/g; Sr, 374.83 μg/g; U, 0.64 μg/g; V, 61.75 μg/g; Zn, 204.75 μg/g; and Zr:76.27 μg/g, and arrangement of the metals from higher to lower mean content in this area is: Fe > Zn > Mn > Sr > Zn > Cr > Zr > V > Ni > Pb > Mo > U > Se. There is no significant correlation among most of these metals, indicating different anthropogenic and natural sources. To assess ecotoxic potential of marine sediments, Numerical Sediment Quality Guidelines were also applied. The concentration of Pb in all the sediments except one was lower than the threshold effect concentration (TECs) showing that there are no harmful effects to marine life from Pb. On the other hand, the concentrations of Cr, Ni, and Zn exceeded TEC in three stations, indicating their potential risk. The degree of pollution in sediments for metals was assessed by calculating enrichment factor (EF) and pollution load index (PLI). The results indicated that sediments of Layari River Mouth Area, Fish Harbour, and KPT Boat Building Area are highly enriched with Cr and Zn (EF > 5). Sediments of Layari River Outfall Zone were moderately enriched with Ni and Pb (EF > 2). The pollution load index was found in the range of 0.98 to 1.34. Lower values of PLI (≤ 1) at most of sampling locations imply no appreciable input from anthropogenic sources. However

  8. Organotin persistence in contaminated marine sediments and porewaters: In situ degradation study using species-specific stable isotopic tracers

    Energy Technology Data Exchange (ETDEWEB)

    Furdek, Martina; Mikac, Nevenka [Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, Zagreb (Croatia); Bueno, Maite; Tessier, Emmanuel; Cavalheiro, Joana [Laboratoire de Chimie Analytique Bio-inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux, CNRS UMR 5254, Université de Pau et des Pays de l’Adour, Hélioparc Pau Pyrénées, 2, Av. P. Angot, 64053 Pau Cedex 9 (France); Monperrus, Mathilde, E-mail: mathilde.monperrus@univ-pau.fr [Laboratoire de Chimie Analytique Bio-inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux, CNRS UMR 5254, Université de Pau et des Pays de l’Adour, Hélioparc Pau Pyrénées, 2, Av. P. Angot, 64053 Pau Cedex 9 (France)

    2016-04-15

    Highlights: • Limiting step in OTC degradation in sediments is their desorption into porewater. • TBT persistence in contaminated sediments increases in sediments rich in organic matter. • DBT does not accumulate in sediments as degradation product of TBT. • TBT and DBT degradation in porewaters occurs with half-lives from 2.9 to 9.2 days. • PhTs degradation is slower than BuTs degradation in oxic porewaters. - Abstract: This paper provides a comprehensive study of the persistence of butyltins and phenyltins in contaminated marine sediments and presents the first data on their degradation potentials in porewaters. The study’s aim was to explain the different degradation efficiencies of organotin compounds (OTC) in contaminated sediments. The transformation processes of OTC in sediments and porewaters were investigated in a field experiment using species-specific, isotopically enriched organotin tracers. Sediment characteristics (organic carbon content and grain size) were determined to elucidate their influence on the degradation processes. The results of this study strongly suggest that a limiting step in OTC degradation in marine sediments is their desorption into porewaters because their degradation in porewaters occurs notably fast with half-lives of 9.2 days for tributyltin (TBT) in oxic porewaters and 2.9 ± 0.1 and 9.1 ± 0.9 days for dibutyltin (DBT) in oxic and anoxic porewaters, respectively. By controlling the desorption process, organic matter influences the TBT degradation efficiency and consequently defines its persistence in contaminated sediments, which thus increases in sediments rich in organic matter.

  9. 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.

  10. 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.

  11. Biochemical and microbial features of shallow marine sediments along the Terra Nova Bay (Ross Sea, Antarctica)

    Science.gov (United States)

    Baldi, Franco; Marchetto, Davide; Pini, Francesco; Fani, Renato; Michaud, Luigi; Lo Giudice, Angelina; Berto, Daniela; Giani, Michele

    2010-09-01

    Shallow marine sediments were collected from seven stations (three of which located at Gerlache Inlet, two at Tethys Bay, one at Adelie Cove and one just beneath the Italian Research Base) along the Terra Nova Bay coast (Ross Sea, Antarctica). Their chemical, biochemical and microbiological properties were studied in order to provide further insights in the knowledge of this Antarctic benthic ecosystem. Overall, the organic carbon (OC) represented the major fraction of total carbon (TC) and displayed concentrations similar to or slightly lower than those previously measured in Antarctic bottom sediments. The biopolymeric carbon within OC ranged from 4.1% to 19.9% and showed a wide trophic range (65-834 μg g -1 d.w.). Proteins (PRT) represented on average the main biochemical class contributing to labile organic carbon, followed by lipids (LIP) and carbohydrates (CHO). The activity of aminopeptidase, β- D-glucosidase, alkaline phosphatase and esterase was checked, giving the highest values at Tethys Bay and at the deepest water sediments. The principal component analysis, which was computed considering physical, chemical (elemental and biochemical sedimentary composition) and microbiological parameters (including bacterial abundance, ectoenzymatic activities, T-RFs richness and diversity indices), allowed to obtain two main clusters ("Tethys Bay" and "other stations"). Based on data obtained, two representative 16S rRNA clone libraries using samples from Tethys Bay and Gerlache Inlet were constructed. The sequences of 171 clones were compared to those available in public databases to determine their approximate phylogenetic affiliations. Both aerobic and anaerobic bacteria were disclosed, with the majority of them affiliated with the Gamma- and Deltaproteobacteria, Bacteroidetes and Acidobacteria. The occurrence of strictly anaerobic bacteria suggests that sediments might also undergo anoxic conditions that, in turn, could favor the accumulation of PRT in respect

  12. 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.

  13. 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.

  14. Discriminative detection and enumeration of microbial life in marine subsurface sediments.

    Science.gov (United States)

    Morono, Yuki; Terada, Takeshi; Masui, Noriaki; Inagaki, Fumio

    2009-05-01

    Detection and enumeration of microbial life in natural environments provide fundamental information about the extent of the biosphere on Earth. However, it has long been difficult to evaluate the abundance of microbial cells in sedimentary habitats because non-specific binding of fluorescent dye and/or auto-fluorescence from sediment particles strongly hampers the recognition of cell-derived signals. Here, we show a highly efficient and discriminative detection and enumeration technique for microbial cells in sediments using hydrofluoric acid (HF) treatment and automated fluorescent image analysis. Washing of sediment slurries with HF significantly reduced non-biological fluorescent signals such as amorphous silica and enhanced the efficiency of cell detachment from the particles. We found that cell-derived SYBR Green I signals can be distinguished from non-biological backgrounds by dividing green fluorescence (band-pass filter: 528/38 nm (center-wavelength/bandwidth)) by red (617/73 nm) per image. A newly developed automated microscope system could take a wide range of high-resolution image in a short time, and subsequently enumerate the accurate number of cell-derived signals by the calculation of green to red fluorescence signals per image. Using our technique, we evaluated the microbial population in deep marine sediments offshore Peru and Japan down to 365 m below the seafloor, which provided objective digital images as evidence for the quantification of the prevailing microbial life. Our method is hence useful to explore the extent of sub-seafloor life in the future scientific drilling, and moreover widely applicable in the study of microbial ecology.

  15. Investigating Deep-Marine Sediment Waves in the Northern Gulf of Mexico Using 3D Seismic Data

    Science.gov (United States)

    Wang, Z.; Gani, M. R.

    2016-12-01

    Deep-water depositional elements have been studied for decades using outcrop, flume tank, sidescan sonar, and seismic data. Even though they have been well recognized by researchers, the improvements in the quality of 3D seismic data with increasingly larger dimension allow detailed analysis of deep-water depositional elements with new insights. This study focuses on the deep-marine sediment waves in the northern Gulf of Mexico. By interpreting a 3D seismic dataset covering 635 km2 at Mississippi Canyon and Viosca Knoll areas, large sediment waves, generated by sediment gravity flows, were mapped and analyzed with various seismic attributes. A succession of sediment waves, approximately 100 m in thickness, is observed on the marine slope that tapers out at the toe of the slope. The individual sediment wave exhibits up to 500 m in wavelength and up to 20 m in height. The wave crests oriented northeast-southwest are broadly aligned parallel to the regional slope-strike, indicating their sediment gravity flow origin. The crestlines are straight or slightly sinuous, with sinuosity increasing downslope. Their anti-dune patterns likely imply the presence of supercritical flows. The sediment waves have a retrogradational stacking pattern. Seismic amplitude maps of each sediment wave revealed that after depositing the majority of sheet-like sands on the upper slope, sediment gravity flows started to form large sediment waves on the lower slope. The steep and narrow upcurrent flanks of the sediment waves always display higher amplitudes than the gentle and wide downcurrent flanks, indicating that the sands were likely preferentially trapped along the upcurrent flanks, whereas the muds spread along the downcurrent flanks. The formation of sediment waves likely requires a moderate sand-mud ratio, as suggested by these observations: (1) absence of sediment waves on the upper slope where the sands were mainly deposited as unconfined sheets with a high sand-mud ratio; (2

  16. Nitrogen cycling and community structure of proteobacterial ß-subgroup ammonia-oxidizing bacteria within polluted marine fish farm sediments

    NARCIS (Netherlands)

    McCaig, A.E.; Phillips, C.B.; Stephen, J.R.; Kowalchuk, G.A.; Harvey, S.M.; Herbert, R.A.; Embley, T.M.; Prosser, J.I.

    1999-01-01

    A multidisciplinary approach was used to study the effects of pollution from a marine fish farm on nitrification rates and on the community structure of ammonia-oxidizing bacteria in the underlying sediment. Organic content, ammonium concentrations, nitrification rates, and ammonia oxidizer most-pro

  17. Low-temperature partial magnetic self-reversal in marine sediments by magnetostatic interaction of titanomagnetite and titanohematite intergrowths

    NARCIS (Netherlands)

    Garming, J.F.L.; Von Dobeneck, T.; Franke, C.; Bleil, U.

    2007-01-01

    With various low-temperature experiments performed on magnetic mineral extracts of marine sedimentary deposits from the Argentine continental slope near the Rio de la Plata estuary, a so far unreported style of partial magnetic self-reversal has been detected. In these sediments the sulphate-methane

  18. Low-temperature partial magnetic self-reversal in marine sediments by magnetostatic interaction of titanomagnetite and titanohematite intergrowths

    NARCIS (Netherlands)

    Garming, J.F.L.; Von Dobeneck, T.; Franke, C.; Bleil, U.

    2007-01-01

    With various low-temperature experiments performed on magnetic mineral extracts of marine sedimentary deposits from the Argentine continental slope near the Rio de la Plata estuary, a so far unreported style of partial magnetic self-reversal has been detected. In these sediments the sulphate-methane

  19. Can bathymetry be a discriminatory factor for the distribution of benthic foraminiferal morpho-groups in modern marine sediments?

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Khare, N.; Mayenkar, D.N.

    The foraminiferal content of one hundred eight modern marine sediment samples off Vengurla-Cochin sector (ranging in water depth from 30 to 1330 m). West Coast of India was studied. A total of two hundred four foraminiferal species (comprised of one...

  20. Methymercury Formation in Marine and Freshwater Systems: Sediment Characteristics, Microbial Activity and SRB Phylogeny Control Formation Rates and Food-Chain Exposure

    Science.gov (United States)

    King, J. K.; Saunders, F. M.

    2004-05-01

    Mercury research in freshwater and marine systems suggests that sediment characteristics such as organic substrate, mercury speciation, and sulfate/sulfide concentrations influence availability of inorganic mercury for methylation. Similarly, sediment characteristics also influence sulfate-reducing bacterial (SRB) respiration as well as the presence/distribution of phylogenetic groups responsible for mercury methylation. Our work illustrates that the process of methylmercury formation in freshwater and marine systems are not dissimilar. Rather, the same geochemical parameters and SRB phylogenetic groups determine the propensity for methylmercury formation and are applicable in both fresh- and marine-water systems. The presentation will include our integration of sediment geochemical and microbial parameters affecting mercury methylation in specific freshwater and marine systems. Constructed wetlands planted with Schoenoplectus californicus and amended with gypsum (CaSO4) have demonstrated a capacity to remove inorganic mercury from industrial outfalls. However, bioaccumulation studies of periphyton, eastern mosquitofish (Gambusia holbrooki) and lake chubsucker (Erimyzon sucetta) were conducted in order to ascertain the availability of wetland-generated methylmercury to biota. Total mercury concentrations in mosquitofish from non-sulfate treated controls and the reference location were significantly lower than those from the low and high sulfate treatments while mean total mercury concentrations in lake chubsuckers were also significantly elevated in the high sulfate treatment compared to the low sulfate, control and reference populations. Methylmercury concentrations in periphyton also corresponded with mercury levels found in the tissue of the lake chubsuckers, and these findings fit well given the trophic levels identified for both species of fish. Overall, data from this study suggest that the initial use of gypsum to accelerate the maturity of a constructed

  1. Distribution of clay minerals in marine sediments off Chennai, Bay of Bengal, India:Indicators of sediment sources and transport processes

    Institute of Scientific and Technical Information of China (English)

    Subramanian VEERASINGAM; Ramdoss VENKATACHALAPATHY; Thirunavukkarasu RAMKUMAR

    2014-01-01

    Clay mineralogy, texture size and statistical analyses were carried out on surface sediments from the continental shelf of Chennai, Bay of Bengal, India. The purpose of this study is to characterize the clay mineral distribution and its relation to the hydrodynamics off Chennai to identify the sources and transport pathways of the marine sediments. Characterization of clay minerals in coastal sediments by Fourier Transform Infrared (FTIR) spectroscopy has provided the association of quartz, feldspar, kaolinite, chlorite, illite and iron oxides (magnetite and hematite) derived from river catchments and coastal erosion. Kaolinite, chlorite, illite, iron oxides, and organic matter are the dominant minerals in Cooum, and Adayar region. High quartz and feldspar zones were identified in Marina, which are being confined the sand zone and paralleling the coast. The strong relationships among the wave energy density, sand, quartz and carbonate revealed that wave induced littoral drift system play a dominant role in transportation and deposition of sediments in the Chennai coast. The sediment texture and minerals data are in agreement well with the previous results of hydrodynamics and littoral drift models in this region. Multivariate statistical analyses (correlation, cluster and factor analyses) were carried out and obtained results suggested that clay minerals and organic matter are trapped in silt and clay particles, whereas quartz, feldspar and carbonate are associated with sand particles. Results of sediment sources and transport processes from this study will be useful to predict the fate of the pollutants released from land or the potential change in sediment delivery to coastal areas.

  2. A New Natural Gamma Radiation Measurement System for Marine Sediment and Rock Analysis

    CERN Document Server

    Vasiliev, M A; Chubarian, G; Olsen, R; Bennight, C; Cobine, T; Fackler, D; Hastedt, M; Houpt, D; Mateo, Z; Vasilieva, Y B

    2010-01-01

    A new high-efficiency and low-background system for the measurement of natural gamma radioactivity in marine sediment and rock cores retrieved from beneath the seabed was designed, built, and installed on the JOIDES Resolution research vessel. The system includes eight large NaI(Tl) detectors that measure adjacent intervals of the core simultaneously, maximizing counting times and minimizing statistical error for the limited measurement times available during drilling expeditions. Effect to background ratio is maximized with passive lead shielding, including both ordinary and low-activity lead. Large-area plastic scintillator active shielding filters background associated with the high-energy part of cosmic radiation. The new system has at least an order of magnitude higher statistical reliability and significantly enhances data quality compared to other offshore natural gamma radiation (NGR) systems designed to measure geological core samples. Reliable correlations and interpretations of cored intervals are ...

  3. A new natural gamma radiation measurement system for marine sediment and rock analysis

    Science.gov (United States)

    Vasiliev, M. A.; Blum, P.; Chubarian, G.; Olsen, R.; Bennight, C.; Cobine, T.; Fackler, D.; Hastedt, M.; Houpt, D.; Mateo, Z.; Vasilieva, Y. B.

    2011-11-01

    A new high-efficiency and low-background system for the measurement of natural gamma radioactivity in marine sediment and rock cores retrieved from beneath the seabed was designed, built, and installed on the JOIDES Resolution research vessel. The system includes eight large NaI(Tl) detectors that measure adjacent intervals of the core simultaneously, maximizing counting times and minimizing statistical error for the limited measurement times available during drilling expeditions. Effect to background ratio is maximized with passive lead shielding, including both ordinary and low-activity lead. Large-area plastic scintillator active shielding filters background associated with the high-energy part of cosmic radiation. The new system has at least an order of magnitude higher statistical reliability and significantly enhances data quality compared to other offshore natural gamma radiation (NGR) systems designed to measure geological core samples. Reliable correlations and interpretations of cored intervals are possible at rates of a few counts per second.

  4. Development of a microscale NOx- biosensor for the study of nitrogen cycling in marine sediment

    DEFF Research Database (Denmark)

    Marzocchi, Ugo

    -) microscale biosensor matches these requirements. In fact, it can be constructed with a tip diameter ranging between 25 and 100 µm. Its functioning is based on the reduction of NOx- to N2O by denitrifying bacteria and the subsequent detection of N2O by means of an amperometric microsensor. The sensitivity...... microbially-mediated long distance electric coupling between redox half reactions in marine sediment. As described in the first manuscript, we optimized the membrane permeabilization procedure in order to decrease the membrane porosity and therefore to increase its sturdiness. Successively, we assessed...... and anodic sulfide oxidation indicating an electric coupling between the half reactions. Successively, by means of a proton-electron-nitrate mass-balance, we estimated that a consistent fraction (ranging from 10 to 78%) of the total nitrate reduction was mediated by long-distance electron transport...

  5. History effects in the sedimentation of light aerosols in turbulence: the case of marine snow

    CERN Document Server

    Guseva, Ksenia; Feudel, Ulrike; Tél, Tamás

    2016-01-01

    We analyze the effect of the Basset history force on the sedimentation of nearly neutrally buoyant particles, exemplified by marine snow, in a three-dimensional turbulent flow. Particles are characterized by Stokes numbers much smaller than unity, and still water settling velocities, measured in units of the Kolmogorov velocity, of order one. The presence of the history force in the Maxey-Riley equation leads to individual trajectories which differ strongly from the dynamics of both inertial particles without this force, and ideal settling tracers. When considering, however, a large ensemble of particles, the statistical properties of all three dynamics become more similar. The main effect of the history force is a rather slow, power-law type convergence to an asymptotic settling velocity of the center of mass, which is found numerically to be the settling velocity in still fluid. The spatial extension of the ensemble grows diffusively after an initial ballistic growth lasting up to ca. one large eddy turnove...

  6. Effective bioremediation strategy for rapid in situ cleanup of anoxic marine sediments in mesocosm oil spill simulation.

    Science.gov (United States)

    Genovese, Maria; Crisafi, Francesca; Denaro, Renata; Cappello, Simone; Russo, Daniela; Calogero, Rosario; Santisi, Santina; Catalfamo, Maurizio; Modica, Alfonso; Smedile, Francesco; Genovese, Lucrezia; Golyshin, Peter N; Giuliano, Laura; Yakimov, Michail M

    2014-01-01

    The purpose of present study was the simulation of an oil spill accompanied by burial of significant amount of petroleum hydrocarbons (PHs) in coastal sediments. Approximately 1000 kg of sediments collected in Messina harbor were spiked with Bunker C furnace fuel oil (6500 ppm). The rapid consumption of oxygen by aerobic heterotrophs created highly reduced conditions in the sediments with subsequent recession of biodegradation rates. As follows, after 3 months of ageing, the anaerobic sediments did not exhibit any significant levels of biodegradation and more than 80% of added Bunker C fuel oil remained buried. Anaerobic microbial community exhibited a strong enrichment in sulfate-reducing PHs-degrading and PHs-associated Deltaproteobacteria. As an effective bioremediation strategy to clean up these contaminated sediments, we applied a Modular Slurry System (MSS) allowing the containment of sediments and their physical-chemical treatment, e.g., aeration. Aeration for 3 months has increased the removal of main PHs contaminants up to 98%. As revealed by CARD-FISH, qPCR, and 16S rRNA gene clone library analyses, addition of Bunker C fuel oil initially affected the activity of autochthonous aerobic obligate marine hydrocarbonoclastic bacteria (OMHCB), and after 1 month more than the third of microbial population was represented by Alcanivorax-, Cycloclasticus-, and Marinobacter-related organisms. In the end of the experiment, the microbial community composition has returned to a status typically observed in pristine marine ecosystems with no detectable OMHCB present. Eco-toxicological bioassay revealed that the toxicity of sediments after treatment was substantially decreased. Thus, our studies demonstrated that petroleum-contaminated anaerobic marine sediments could efficiently be cleaned through an in situ oxygenation which stimulates their self-cleaning potential due to reawakening of allochtonous aerobic OMHCB.

  7. Effective bioremediation strategy for rapid in situ cleanup of anoxic marine sediments in mesocosm oil spill simulation.

    Directory of Open Access Journals (Sweden)

    Maria eGenovese

    2014-04-01

    Full Text Available The purpose of present study was the simulation of an oil spill accompanied by burial of significant amount of petroleum hydrocarbons (PHs in coastal sediments. Approximately 1,000 kg of sediments collected in Messina harbor were spiked with Bunker C furnace fuel oil (6,500 ppm. The rapid consumption of oxygen by aerobic heterotrophs created highly reduced conditions in the sediments with subsequent recession of biodegradation rates. As follows, after three months of ageing, the anaerobic sediments did not exhibit any significant levels of biodegradation and more than 80% of added Bunker C fuel oil remained buried. Anaerobic microbial community exhibited a strong enrichment in sulfate-reducing PHs-degrading and PHs-associated Deltaproteobacteria. As an effective bioremediation strategy to clean up these contaminated sediments, we applied a Modular Slurry System (MSS allowing the containment of sediments and their physical-chemical treatment, e.g. aeration. Aeration for three months has increased the removal of main PHs contaminants up to 98%. As revealed by CARD-FISH, qPCR and 16S rRNA gene clone library analyses, addition of Bunker C fuel oil initially affected the activity of autochthonous aerobic obligate marine hydrocarbonoclastic bacteria (OMHCB, and after one month more than the third of microbial population was represented by Alcanivorax-, Cycloclasticus- and Marinobacter-related organisms. In the end of the experiment, the microbial community composition has returned to a status typically observed in pristine marine ecosystems with no detectable OMHCB present. Eco-toxicological bioassay revealed that the toxicity of sediments after treatment was substantially decreased. Thus, our studies demonstrated that petroleum-contaminated anaerobic marine sediments could efficiently be cleaned through an in situ oxygenation which stimulates their self-cleaning potential due to reawakening of allochtonous aerobic OMHCB.

  8. Methylmercury determination in marine sediment and organisms by Direct Mercury Analyser

    Energy Technology Data Exchange (ETDEWEB)

    Maggi, Chiara; Berducci, Maria Teresa [Advanced Institute for Environmental Protection and Research - ISPRA, Via di Casalotti 300, Rome (Italy); Bianchi, Jessica, E-mail: j.bianchi@icram.org [Advanced Institute for Environmental Protection and Research - ISPRA, Via di Casalotti 300, Rome (Italy); Giani, Michele [National Institute of Oceanography and Experimental Geophysics, Biological Oceanography Department, Via Piccard 54, 34100 Trieste (Italy); Campanella, Luigi [Chemical Department University ' La Sapienza' , P.le Aldo Moro 5, 00185 Rome (Italy)

    2009-05-08

    An analytical method for simple and rapid determination of methylmercury in sediment and organism samples is described. The proposed method employs the oxygen combustion-gold amalgamation using Direct Mercury Analyser (DMA-80) after complete removal of MeHg by organic extraction and back extraction to an aqueous medium. DMA-80 instrument is equally suitable for the analysis of solid and liquid materials and has a good detection limit. The analytical performance of this method was evaluated by analysis of certified reference materials (CRM-580, IAEA-405, DORM-2, DOLT-3, SRM-2976 and SRM-2977) assessing its quality in terms of accuracy, repeatability and quantification limit. Furthermore total mercury and methylmercury have been analysed in sediment and organism samples collected during the XXI Italian Antarctic Expedition in Terra Nova Bay (Ross Sea, Northern Victoria Land). The results obtained show the validity of the proposed method as ready-to-use analytical method to analyse real samples.

  9. Environmental and ecological risk of heavy metals in the marine sediment from Dakhla Bay, Morocco.

    Science.gov (United States)

    Hakima, Zidane; Mohamed, Maanan; Aziza, Mouradi; Mehdi, Maanan; Meryem, El Barjy; Bendahhou, Zourarah; Jean-Francois, Blais

    2017-01-20

    Heavy metal assessment in Dakhla Bay (Atlantic coast) was carried out using different environmental and ecological indices. Heavy metal concentrations were measured using ICP-AES and were compared with consensus-based sediment quality guidelines. The distribution of heavy metal concentrations varies for the three groups: (i) lead distribution is dominated by its associations with copper and chromium. These elements have the same source, most probably related to anthropogenic activities. (ii) Nickel, zinc and cobalt are associated with aluminium and iron indicating their terrigenous origin (natural content), and (iii) cadmium concentration is related to upwelling currents. This paper systematically studied the distributions and pollution levels of heavy metals in sediment in the coastal areas in Dakhla Bay, which is of scientific significance, to discuss the changing rules and the affecting factors of the harmful heavy metals and can be adopted for reference to other coastal areas.

  10. Dispersed Ash in Marine Sediment: An Overview Towards Unraveling the 'Missing Volcanic Record'

    Science.gov (United States)

    Murray, R. W.; Scudder, R.; Kutterolf, S.; Schindlbeck, J.

    2013-12-01

    Volcanic ash occurs in marine sediment both as discrete layers as well as isolated grains and shards dispersed throughout the bulk sediment, and with highly variable grain sizes. The study of this dispersed component has lagged behind the sophisticated petrographic, sedimentologic, geochemical, and isotopic assessment of the ash layer record. For example, while decades of smear-slide studies of bulk sediment in volcanic-rich regimes have presented visual estimations of the abundance of 'volcanic glass', 'shards', and/or other components, the quantitative importance of the dispersed ash and/or the cryptotephra component remains largely unconstrained on local, regional, and global scales. Chemical and isotopic characterization of this dispersed component has remained elusive. Building on earlier work, research in the 1970s began documenting the importance of dispersed ash and its alteration products. This dispersed ash is the result of the bioturbation of pre-existing discrete layers, the settling of airborne ash, distribution from subaqueous eruptions, and other mechanisms. Compared to the often visually stunning ash layer records, which in certain settings can leave single layers with thicknesses of 10s of cm, the dispersed ash component and cryptotephra layers are unable to be visually differentiated from detrital clay. Furthermore, its extremely fine grain size is an additional hindrance to quantification of its abundance and the identification of source. More completely characterizing the total ash inventory (that is, the dispersed ash in addition to the ash layers) will contribute significantly to studies of marine and terrestrial volcanism at many scales, geochemical mass balances, arc evolution, hydration of marine sediment during alteration, atmospheric circulation, putative relationships between volcanism and climate, and other key components of the earth-ocean-atmosphere system. Beginning with work in the Caribbean Sea and progressing to the northwest

  11. The Relative Importance of Terrestrial Versus Marine Sediment Sources to the Nueces- Corpus Christi Estuary, Texas: An Isotopic Approach

    Science.gov (United States)

    Yeager, K. M.; Santschi, P. H.; Schindler, K. J.; Andres, M. J.; Weaver, E. A.

    2006-05-01

    Determining principle sources of sediment to coastal systems is an important and complex problem that figures prominently in a myriad of geological, geomorphological, geochemical and biological processes. Lithogenic (226Ra, 228Ra, 228Th, 230Th, 232Th) and fallout (137Cs, 210Pb) isotopes were used in conjunction with sedimentological methods to determine rates of sedimentation in the Nueces Delta and Nueces-Corpus Christi Estuary and to assess the relative importance of marine versus terrestrial sediment sources to the estuary. Sampling focused primarily on the lower Nueces River, Nueces Delta, Nueces Bay, Corpus Christi Bay, Gulf Intracoastal Waterway (GIW) and Gulf of Mexico (GOM). Gain size data show GIW and GOM sediments to be dominantly sands, Corpus Christi Bay sediments to be dominantly clays and sediments from all other sampled areas to be more homogenized in grain size, suggesting that near shore oceanic sediments are sands derived predominantly from long shore transport in the littoral zone. Bed load and suspended sediments sourced from the Nueces River provide sand and fines to the Nueces Delta and Bay, where the coarser size fractions are effectively retained. Similarity of lithogenic isotope ratios in surface sediment types throughout the system precluded a numeric approach to discerning the importance of each of the two large scale sediment source areas (terrestrial and marine). A stepwise, graphical examination of discrete lithogenic isotope activity concentrations shows more promise. Terrestrial, marine and bay sediment means for 226Ra v. 232Th, 226Ra v. 230Th and 228Ra v. 232Th show that terrestrial and marine sediment sources have different signatures, despite having a similar grain size distribution (sands), and that sediment deposited in Nueces and Corpus Christi Bays are indistinguishable from the terrestrial component. Supporting evidence is provided by thorium isotopes, 230Th v. 232Th, 228Th v. 232Th and 228Th v. 230Th. Nueces Delta

  12. A transfer function for the prediction of gas hydrate inventories in marine sediments

    Directory of Open Access Journals (Sweden)

    M. Marquardt

    2010-09-01

    Full Text Available A simple prognostic tool for gas hydrate (GH quantification in marine sediments is presented based on a diagenetic transport-reaction model approach. One of the most crucial factors for the application of diagenetic models is the accurate formulation of microbial degradation rates of particulate organic carbon (POC and the coupled formation of biogenic methane. Wallmann et al. (2006 suggested a kinetic formulation considering the ageing effects of POC and accumulation of reaction products (CH4, CO2 in the pore water. This model is applied to data sets of several ODP sites in order to test its general validity. Based on a thorough parameter analysis considering a wide range of environmental conditions, the POC accumulation rate (POCar in g/m2/yr and the thickness of the gas hydrate stability zone (GHSZ in m were identified as the most important and independent controls for biogenic GH formation. Hence, depth-integrated GH inventories in marine sediments (GHI in g of CH4 per cm2 seafloor area can be estimated as:

    GHI = a · POCar · GHSZb · exp (– GHSZc/POCar/d + e

    with a = 0.00214, b = 1.234, c = –3.339,

            d = 0.3148, e = –10.265.

    The transfer function gives a realistic first order approximation of the minimum GH inventory in low gas flux (LGF systems. The overall advantage of the presented function is its simplicity compared to the application of complex numerical models, because only two easily accessible parameters need to be determined.

  13. Paleoclimatic and paleoceanographic studies of estuarine and marine sediments using strontium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ingram, B.L.

    1992-01-01

    Strontium isotopic ratio ([sup 87]Sr/[sup 86]Sr) measurements in fossil carbonates and phosphates are used to evaluate paleoceanographic and paleoclimatic environments in Quaternary, Pliocene-Pleistocene, and mid-Cretaceous estuarine and marine sediments. The use of [sup 87]Sr/[sup 86]Sr measurements as an estuarine paleosalinity and paleoclimatic indicator is developed and applied to San Francisco Bay. [sup 87]Sr/[sup 86]Sr measurements of foraminifer and molluscan fossils contained in estuarine sediments of late Pleistocene (ca 115 to 125 ka) and late Holocene (4.5 ka) age show cyclic variations indicating that salinity fluctuated with periods of several hundred years, probably reflecting wet-dry cycles associated with fluctuations in solar irradiance caused by sunspot cycles. The average salinity in San Pablo and Richardson bays was significantly lower (by 6 to 8%) over much of the past 4.5 ka than at present, reflecting a combination of decreased freshwater inflow at present associated with water diversion and wetter climatic conditions prior to 2000 years ago. Salinity data are converted to river discharge using salinity-delta flow relations derived from historical records for San Francisco Bay. The data indicate that annual freshwater inflow was at least twice the modern pre-diversion average between 2.5 and 3.0 Ka; this time period is also identified as one of wetter climatic conditions by lake level and treeline records from the Sierra Nevada. Strontium isotopic measurements of marine carbonate and fish teeth to middle Cretaceous age are used to increase the resolution of the existing seawater Sr isotope versus time curve and to assess models for global oceanic anoxic events. The new data using fish teeth show less scatter and variability than previous data. Negative excursions in the [sup 87]Sr/[sup 86]Sr ratio of 7-14 parts in 10[sup [minus]5] during Aptian anoxic events suggest a link between increased submarine volcanism and oceanic anoxia.

  14. Insights on frictional processes in sheared clastic marine sediments using ultrasonic nondestructive testing

    Science.gov (United States)

    Knuth, M. W.; Tobin, H. J.; Marone, C.; Ikari, M.

    2010-12-01

    We investigate changes in the elastic properties of deforming core materials recovered from the Nankai Trough Accretionary Prism along the IODP NanTroSEIZE transect. We shear clastic marine sediments while simultaneously making ultrasonic velocity measurements across the deforming layers. Examining the resulting changes in elastic moduli at the laboratory scale allows us to identify characteristic “fingerprints” of deformation style during direct-shear experiments, which may then be compared with measurements conducted at the field scale to infer how deformation is localized within the accretionary prism. Identifying relationships between hold time and attenuation may also shed light on fault healing mechanisms taking place immediately following a rupture. Together the effects of sliding rate and hold time on elastic moduli provide us with new ways of constraining the mechanical behavior of large plat-boundary settings throughout the seismic cycle. We tested intact core material, remolded layers, and disaggregated granular powders derived from a range of depths from IODP sites C0007 and C0004 penetrating the frontal thrust and a large out-of-sequence thrust in the outer prism, respectively. Samples were deformed in a double-direct shear configuration, varying first the strain rate and then subjecting the gouge layer to a series of slides and holds of increasing duration. Elastic wave propagation depends on micromechanical interactions and gouge layer strength, so as the shear zone evolves changes in elastic wavespeed provide a means to interrogate strain materials non-destructively, providing insight into frictional processes and mechanics as that deformation is taking place. Our results suggest that there are characteristic changes in P and S-wave velocity and attenuation for marine clastic to hemipelagic sediments as a function of sliding rate and hold time. Ultimately, examining variation in elastic moduli during a simulated seismic cycle may provide insight

  15. A transfer function for the prediction of gas hydrate inventories in marine sediments

    Directory of Open Access Journals (Sweden)

    M. Marquardt

    2010-02-01

    Full Text Available A simple prognostic tool for gas hydrate (GH quantification in marine sediments is presented based on a diagenetic transport-reaction model approach. One of the most crucial factors for the application of diagenetic models is the accurate formulation of microbial degradation rates of particulate organic carbon (POC and the coupled biogenic CH4 formation. Wallmann et al. (2006 suggested a kinetic formulation considering the ageing effects of POC and accumulation of reaction products (CH4, CO2 in the pore water. This model is applied to data sets of several ODP sites in order to test its general validity. Based on a thorough parameter analysis considering a wide range of environmental conditions, the POC accumulation rate (POCar in g/cm2/yr and the thickness of the gas hydrate stability zone (GHSZ in m were identified as the most important and independent controls for biogenic GH formation. Hence, depth-integrated GH inventories in marine sediments (GHI in g of CH4 per cm2 seafloor area can be estimated as:

    GHI = a · POCar · GHSZb · exp (−GHSZc/POCar/d + e

    with a = 0.00214, b = 1.234, c = −3.339, d = 0.3148, e = −10.265.

    Several tests indicate that the transfer function gives a realistic approximation of the minimum potential GH inventory of low gas flux (LGF systems. The overall advantage of the presented function is its simplicity compared to complex numerical models: only two easily accessible parameters are needed.

  16. 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.

  17. Microbial colonization and degradation of polyethylene and biodegradable plastic bags in temperate fine-grained organic-rich marine sediments.

    Science.gov (United States)

    Nauendorf, Alice; Krause, Stefan; Bigalke, Nikolaus K; Gorb, Elena V; Gorb, Stanislav N; Haeckel, Matthias; Wahl, Martin; Treude, Tina

    2016-02-15

    To date, the longevity of plastic litter at the sea floor is poorly constrained. The present study compares colonization and biodegradation of plastic bags by aerobic and anaerobic benthic microbes in temperate fine-grained organic-rich marine sediments. Samples of polyethylene and biodegradable plastic carrier bags were incubated in natural oxic and anoxic sediments from Eckernförde Bay (Western Baltic Sea) for 98 days. Analyses included (1) microbial colonization rates on the bags, (2) examination of the surface structure, wettability, and chemistry, and (3) mass loss of the samples during incubation. On average, biodegradable plastic bags were colonized five times higher by aerobic and eight times higher by anaerobic microbes than polyethylene bags. Both types of bags showed no sign of biodegradation during this study. Therefore, marine sediment in temperate coastal zones may represent a long-term sink for plastic litter and also supposedly compostable material.

  18. Heavy metal content in coral reef sediments from Red Sea of Yemen and its significance on marine environment

    Institute of Scientific and Technical Information of China (English)

    Nabil A. AL-SHAWAFI; Abdulhakeem AL-KHOLIDI; Aref M.O. AL-JABALI

    2009-01-01

    In order to determine and assess the concentrations of trace elements in coral reefs sediments from Red Sea of Yemen, sediment samples were collected, treated and analyzed for cadmium, chromium, cobalt, copper, manganese, nickel, iead, iron, zinc and vanadium by the atomic absorption spectrometric analysis. The result is that cadmium, cobalt and lead concentrations were high and other elements are low or the same as natural background. It is concluded that the high cadmium, cobalt and lead levels in coral reefs sediments will have negative effects on marine life of the sites, so further researches are needed to characterize the sources fate, biogeochemical processes and impacts of these trace elements on coral reefs and marine of the region.

  19. Effects of prokaryotic diversity changes on hydrocarbon degradation rates and metal partitioning during bioremediation of contaminated anoxic marine sediments.

    Science.gov (United States)

    Rocchetti, Laura; Beolchini, Francesca; Hallberg, Kevin B; Johnson, D Barrie; Dell'Anno, Antonio

    2012-08-01

    We investigated changes of prokaryotic diversity during bioremediation experiments carried out on anoxic marine sediments characterized by high hydrocarbon and metal content. Microcosms containing contaminated sediments were amended with lactose and acetate and incubated in anaerobic conditions up to 60 d at 20 or 35 °C. Microcosms displaying higher degradation efficiency of hydrocarbons were characterized by the dominance of Alphaproteobacteria and Methanosarcinales and the lack of gene sequences belonging to known hydrocarbonoclastic bacteria. Multivariate analyses support the hypothesis that Alphaproteobacteria are important for hydrocarbon degradation and highlight a potential synergistic effect of archaea and bacteria in changes of metal partitioning. Overall, these results point out that the identification of changes in the prokaryotic diversity during bioremediation of contaminated marine sediments is not only important for the improvement of bio-treatment performance towards hydrocarbons, but also for a better comprehension of changes occurring in metal partitioning which affect their mobility and toxicity.

  20. Compound specific amino acid δ15N in marine sediments: A new approach for studies of the marine nitrogen cycle

    Science.gov (United States)

    Batista, Fabian C.; Ravelo, A. Christina; Crusius, John; Casso, Michael A.; McCarthy, Matthew D.

    2014-10-01

    The nitrogen (N) isotopic composition (δ15N) of bulk sedimentary N (δ15Nbulk) is a common tool for studying past biogeochemical cycling in the paleoceanographic record. Empirical evidence suggests that natural fluctuations in the δ15N of surface nutrient N are reflected in the δ15N of exported planktonic biomass and in sedimentary δ15Nbulk. However, δ15Nbulk is an analysis of total combustible sedimentary N, and therefore also includes mixtures of N sources and/or selective removal or preservation of N-containing compounds. Compound-specific nitrogen isotope analyses of individual amino acids (δ15NAA) are novel measurements with the potential to decouple δ15N changes in nutrient N from trophic effects, two main processes that can influence δ15Nbulk records. As a proof of concept study to examine how δ15NAA can be applied in marine sedimentary systems, we compare the δ15NAA signatures of surface and sinking POM sources with shallow surface sediments from the Santa Barbara Basin, a sub-oxic depositional environmental that exhibits excellent preservation of sedimentary organic matter. Our results demonstrate that δ15NAA signatures of both planktonic biomass and sinking POM are well preserved in such surface sediments. However, we also observed an unexpected inverse correlation between δ15N value of phenylalanine (δ15NPhe; the best AA proxy for N isotopic value at the base of the food web) and calculated trophic position. We used a simple N isotope mass balance model to confirm that over long time scales, δ15NPhe values should in fact be directly dependent on shifts in ecosystem trophic position. While this result may appear incongruent with current applications of δ15NAA in food webs, it is consistent with expectations that paleoarchives will integrate N dynamics over much longer timescales. We therefore propose that for paleoceanographic applications, key δ15NAA parameters are ecosystem trophic position, which determines relative partitioning of 15N

  1. Macromolecular composition of terrestrial and marine organic matter in sediments across the East Siberian Arctic Shelf

    Science.gov (United States)

    Sparkes, Robert B.; Doğrul Selver, Ayça; Gustafsson, Örjan; Semiletov, Igor P.; Haghipour, Negar; Wacker, Lukas; Eglinton, Timothy I.; Talbot, Helen M.; van Dongen, Bart E.

    2016-10-01

    Mobilisation of terrestrial organic carbon (terrOC) from permafrost environments in eastern Siberia has the potential to deliver significant amounts of carbon to the Arctic Ocean, via both fluvial and coastal erosion. Eroded terrOC can be degraded during offshore transport or deposited across the wide East Siberian Arctic Shelf (ESAS). Most studies of terrOC on the ESAS have concentrated on solvent-extractable organic matter, but this represents only a small proportion of the total terrOC load. In this study we have used pyrolysis-gas chromatography-mass spectrometry (py-GCMS) to study all major groups of macromolecular components of the terrOC; this is the first time that this technique has been applied to the ESAS. This has shown that there is a strong offshore trend from terrestrial phenols, aromatics and cyclopentenones to marine pyridines. There is good agreement between proportion phenols measured using py-GCMS and independent quantification of lignin phenol concentrations (r2 = 0.67, p < 0.01, n = 24). Furfurals, thought to represent carbohydrates, show no offshore trend and are likely found in both marine and terrestrial organic matter. We have also collected new radiocarbon data for bulk OC (14COC) which, when coupled with previous measurements, allows us to produce the most comprehensive 14COC map of the ESAS to date. Combining the 14COC and py-GCMS data suggests that the aromatics group of compounds is likely sourced from old, aged terrOC, in contrast to the phenols group, which is likely sourced from modern woody material. We propose that an index of the relative proportions of phenols and pyridines can be used as a novel terrestrial vs. marine proxy measurement for macromolecular organic matter. Principal component analysis found that various terrestrial vs. marine proxies show different patterns across the ESAS, and it shows that multiple river-ocean transects of surface sediments transition from river-dominated to coastal-erosion-dominated to marine

  2. A new Certified Reference Material for radionuclides in Irish sea sediment (IAEA-385)

    Energy Technology Data Exchange (ETDEWEB)

    Pham, M.K. [Marine Environment Laboratories, International Atomic Energy Agency, MC 98000 Principality of Monaco (Monaco)], E-mail: m.pham@iaea.org; Sanchez-Cabeza, J.A.; Povinec, P.P. [Marine Environment Laboratories, International Atomic Energy Agency, MC 98000 Principality of Monaco (Monaco); Andor, K. [Frederic Joliot-Curie National Research Inst. for Radiobiology and Radiohygiene, Anna u. 5, 1221 Budapest (Hungary); Arnold, D. [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany); Benmansour, M. [Centre National de l' Energies des Sciences et des Techniques Nucleaires, 1382 Agdal, Rabat 10001 (Morocco); Bikit, I. [Dept. of Physics, Faculty of Science and Mathematics, University of Novi Sad, Trg Dositeja Obradovica 4, 21000 Novi Sad, Serbia (Serbia ); Carvalho, F.P. [Instituto Tecnologico e Nuclear, E.N. 10, P-2686-953 Sacavem (Portugal); Dimitrova, K. [Executive Environment Agency of Bulgaria, Regional Laboratory Varna, 4 Jan Palah Str., Varna 9000 (Bulgaria); Edrev, Z.H. [Regional Inspectorate of Environment and Waters, 2 Stara Planina str., 6000 Stara Zagora (Bulgaria); Engeler, C. [Radiochemistry Dept., Institute for Inland Water Management and Waste Water Treatment, P.O. Box 17, 8200 AA Lelystad (Netherlands); Fouche, F.J. [South African Nuclear Energy Corporation NECSA Ltd., P.O. Box 582, Pretoria 0001 (South Africa); Garcia-Orellana, J. [Dept. de Fisica, Universitat Automona de Barcelona, 08193-Cerdanyola del Valles (Spain); Gasco, C. [Instituto de Medio Ambiente, Radioecologia del Medio Acuatico, Av. de la Complutense 22, 28040 Madrid (Spain); Gastaud, J. [Marine Environment Labs., International Atomic Energy Agency, MC 98000 Principality of Monaco (Monaco); Gudelis, A. [Institute of Physics, Nuclear and Environmental Radioactivity Research Lab., Savanoriu Ave 231, 2053 Vilnius (Lithuania); Hancock, G. [CSIRO Land and Water, Clunies Ross St., GPO Box 1666, Canberra, ACT 2601 (Australia)] (and others)

    2008-11-15

    A new Certified Reference Material (CRM) for radionuclides in sediment (IAEA-385) is described and the results of the certification process are presented. Eleven radionuclides ({sup 40}K, {sup 137}Cs, {sup 226}Ra, {sup 228}Ra, {sup 230}Th, {sup 232}Th, {sup 234}U, {sup 238}U, {sup 238}Pu, {sup 239+240}Pu and {sup 241}Am) have been certified and information mass activities with 95% confidence intervals are given for seven other radionuclides ({sup 90}Sr, {sup 210}Pb({sup 210}Po), {sup 235}U, {sup 239}Pu, {sup 240}Pu and {sup 241}Pu). Results for less frequently reported radionuclides ({sup 60}Co, {sup 99}Tc, {sup 134}Cs, {sup 155}Eu, {sup 224}Ra and {sup 239}Np) and information on some activity and mass ratios are also reported. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in sediment samples, for the development and validation of analytical methods and for training purposes.

  3. Origin and geochemical behavior of uranium in marine sediments. Utilization of the {sup 234}U/{sup 238}U ratio in marine geochemistry; Origine et comportement geochimique de l`uranium dans les sediments marins. Utilisation du rapport ({sup 234}U/{sup 238}U) en geochimie marine

    Energy Technology Data Exchange (ETDEWEB)

    Organo, Catherine [Paris-11 Univ., 91 - Orsay (France)

    1997-01-20

    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 {sup 234}U/2{sup 38U} 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 {sup 234}U/{sup 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 146 refs., 57 figs., 23 tabs.

  4. Saharan dust from a marine perspective: sediment-trap time series off Mauritania

    Science.gov (United States)

    Friese, Carmen; Stuut, Jan-Berend; van der Does, Michelle; Fischer, Gerhard

    2014-05-01

    The particle size of mineral dust is often used as a tool to reconstruct paleoenvironmental conditions in the source of the dust. Both in on-land (loess), lacustrine, and in marine archives, the size of dust deposits is considered a proxy for paleo-wind intensity. However, next to wind strength, the particle size of aeolian deposits is also influenced by various other parameters such as source-to-sink distance, altitude at which the particles have been transported, and various other environmental conditions in the sources of the dust. To verify if we can quantify a relationship between the size of mineral dust particles and prevailing environmental conditions, we study "modern" dust. Here we present grain-size distributions of Saharan dust that was collected in a marine sediment trap, which is situated off Cape Blanc, ~400 km offshore the Mauritanian coast. In this trap, dust is collected that is sinking through the water column to the ocean floor. The temporal resolution of the trap is 1-2 weeks. The time series was started in the late 1980's and is still being continued.

  5. Marine sediment cores database for the Mediterranean Basin: a tool for past climatic and environmental studies

    Science.gov (United States)

    Alberico, I.; Giliberti, I.; Insinga, D. D.; Petrosino, P.; Vallefuoco, M.; Lirer, F.; Bonomo, S.; Cascella, A.; Anzalone, E.; Barra, R.; Marsella, E.; Ferraro, L.

    2017-06-01

    Paleoclimatic data are essential for fingerprinting the climate of the earth before the advent of modern recording instruments. They enable us to recognize past climatic events and predict future trends. Within this framework, a conceptual and logical model was drawn to physically implement a paleoclimatic database named WDB-Paleo that includes the paleoclimatic proxies data of marine sediment cores of the Mediterranean Basin. Twenty entities were defined to record four main categories of data: a) the features of oceanographic cruises and cores (metadata); b) the presence/absence of paleoclimatic proxies pulled from about 200 scientific papers; c) the quantitative analysis of planktonic and benthonic foraminifera, pollen, calcareous nannoplankton, magnetic susceptibility, stable isotopes, radionuclides values of about 14 cores recovered by Institute for Coastal Marine Environment (IAMC) of Italian National Research Council (CNR) in the framework of several past research projects; d) specific entities recording quantitative data on δ18O, AMS 14C (Accelerator Mass Spectrometry) and tephra layers available in scientific papers. Published data concerning paleoclimatic proxies in the Mediterranean Basin are recorded only for 400 out of 6000 cores retrieved in the area and they show a very irregular geographical distribution. Moreover, the data availability decreases when a constrained time interval is investigated or more than one proxy is required. We present three applications of WDB-Paleo for the Younger Dryas (YD) paleoclimatic event at Mediterranean scale and point out the potentiality of this tool for integrated stratigraphy studies.

  6. Experimental Research on the Marine Hydrodynamic Action on the Consolidation Process of the Sediments in the Yellow River Estuary

    Institute of Scientific and Technical Information of China (English)

    YANG Xiu-juan; JIA Yong-gang; LI Xiang-ran; SHAN Hong-xian

    2011-01-01

    Based on the in-situ measurements,the impact of the marine hydrodynamics,such as wave and tide,in the rapidly deposited sediments consolidation process was studied.In the tide flat of Diaokou delta-lobe,one 2m×1m×1m test pit was excavated.The seabed soils were dug and dehydrated,and then the powder of the soil was mixed with seawater to be fluid sediments.And an iron plate covered part of the test pit to cut off the effect of the marine hydrodynamics.By field-testing methods,like static cone penetration test(SPT)and vane shear test(VST),the variation of strength is measured as a function of time,and the marine hydrodynamics impact on the consolidation process of the sediments in the Yellow River estuary was studied.It is shown that the self-consolidated sediments'strength linearly increases with the depth.In the consolidation process,in the initial,marine hydrodynamics play a decisive role,about 1.5 times as much as self-consolidated in raising the strength of the sea-bed soils,and with the extension of the depth the role of the hydrodynamics is reduced.In the continuation of the consolidation process,the trend of the surface sediments increased-strength gradually slows down under the water dynamics,while the sediments below 50 cm are in opposite ways.As a result,the rapidly deposited silt presents a nonuniform consolidation state,and the crust gradually forms.The results have been referenced in studying the role of the hydrodynamics in the soil consolidation process.

  7. Sources and fate of microplastics in marine and beach sediments of the Southern Baltic Sea-a preliminary study.

    Science.gov (United States)

    Graca, Bożena; Szewc, Karolina; Zakrzewska, Danuta; Dołęga, Anna; Szczerbowska-Boruchowska, Magdalena

    2017-03-01

    Microplastics' (particles size ≤5 mm) sources and fate in marine bottom and beach sediments of the brackish are strongly polluted Baltic Sea have been investigated. Microplastics were extracted using sodium chloride (1.2 g cm(-3)). Their qualitative identification was conducted using micro-Fourier-transform infrared spectroscopy (μFT-IR). Concentration of microplastics varied from 25 particles kg(-1) d.w. at the open sea beach to 53 particles kg(-1) d.w. at beaches of strongly urbanized bay. In bottom sediments, microplastics concentration was visibly lower compared to beach sediments (0-27 particles kg(-1) d.w.) and decreased from the shore to the open, deep-sea regions. The most frequent microplastics dimensions ranged from 0.1 to 2.0 mm, and transparent fibers were predominant. Polyester, which is a popular fabrics component, was the most common type of microplastic in both marine bottom (50%) and beach sediments (27%). Additionally, poly(vinyl acetate) used in shipbuilding as well as poly(ethylene-propylene) used for packaging were numerous in marine bottom (25% of all polymers) and beach sediments (18% of all polymers). Polymer density seems to be an important factor influencing microplastics circulation. Low density plastic debris probably recirculates between beach sediments and seawater in a greater extent than higher density debris. Therefore, their deposition is potentially limited and physical degradation is favored. Consequently, low density microplastics concentration may be underestimated using current methods due to too small size of the debris. This influences also the findings of qualitative research of microplastics which provide the basis for conclusions about the sources of microplastics in the marine environment.

  8. Shallow marine sedimentation within an active margin basin, James Ross Island, Antarctica

    Science.gov (United States)

    Pirrie, Duncan

    1989-06-01

    The Santa Marta Formation exposed on northern James Ross Island, Antarctica, represents shallow marine shelf sedimentation within an active margin basin. The formation is approximately 1000 m thick, is of uppermost Santonian to Campanian age and represents part of a 5000-6000 m thick sedimentary sequence forming the Larsen Basin. The Larsen Basin represents either a back-arc basin, or a half-graben basin, developed on the extending margin of the Weddell Sea. Twelve sedimentary facies have been recognised, which can be subdivided into two groups: those which are controlled by shelf processes and those which are related to active arc volcanism. Background shelf processes include fair-weather suspension sedimentation, storm sands and rare tidal current reworking. Active arc processes include direct settling of airfall detritus and rapid resedimentation of volcaniclastic detritus by sandy debris-flows and both high- and low-concentration turbidity currents. In addition sheet conglomerates represent debris flows that evolved from syn-sedimentary slumps. Two facies associations representing a mid to outer shelf and an inner shelf depositional setting respectively can be distinguished, with an apparent regression in the ?mid to late Campanian.

  9. Dissolution of fluoride complexes following microwave-assisted hydrofluoric acid digestion of marine sediments.

    Science.gov (United States)

    Muratli, Jesse M; McManus, James; Mix, Alan; Chase, Zanna

    2012-01-30

    Microwave-assisted, hydrofluoric acid digestion is an increasingly common tool for the preparation of marine sediment samples for analysis by a variety of spectrometric techniques. Here we report that analysis of terrigenous-dominated sediment samples occasionally results in anomalously low values for several elements, including Al, Ba, Ca, Mg, and Sr. Measured concentrations of these elements increased with time between sample preparation and sample analysis, reaching stable values after 8-29 days. This lag is explained by the formation and subsequent dissolution of poorly soluble fluoride phases during digestion. Other elements, such as Fe, Mn, and Ti, showed little or no lag and were quickly measurable at a stable value. Full re-dissolution of the least soluble fluorides, which incorporate Al and Mg, requires up to four weeks at room temperature, and this duration can vary among sedimentary matrices. This waiting time can be reduced to 6 days (or shorter) if the samples are heated to ≈ 60°C for 24h.

  10. Treatability assessment of polycyclic aromatic hydrocarbons contaminated marine sediments using permanganate, persulfate and Fenton oxidation processes.

    Science.gov (United States)

    Shih, Yu-Jen; Binh, Nguyen Thanh; Chen, Chiu-Wen; Chen, Chih-Feng; Dong, Cheng-Di

    2016-05-01

    Various chemical oxidation techniques, such as potassium permanganate (KMnO4), sodium persulfate (Na2S2O8), Fenton (H2O2/Fe(2+)), and the modified persulfate and Fenton reagents (activated by ferrous complexes), were carried out to treat marine sediments that were contaminated with polycyclic aromatic hydrocarbons (PAHs) and dredged from Kaohsiung Harbor in Taiwan. Experimental results revealed that KMnO4 was the most effective of the tested oxidants in PAH degradation. Owing to the high organic matter content in the sediment that reduced the efficiencies of Na2S2O8 and regular Fenton reactions, a large excess of oxidant was required. Nevertheless, KH2PO4, Na4P2O7 and four chelating agents (EDTA, sodium citrate, oxalic acid, and sodium oxalate) were utilized to stabilize Fe(II) in activating the Na2S2O8 and Fenton oxidations, while Fe(II)-citrate remarkably promoted the PAH degradation. Increasing the molecular weight and number of rings of PAH did not affect the overall removal efficiencies. The correlation between the effectiveness of the oxidation processes and the physicochemical properties of individual PAH was statistically analyzed. The data implied that the reactivity of PAH (electron affinity and ionization potential) affected its treatability more than did its hydrophobicity (Kow, Koc and Sw), particularly using experimental conditions under which PAHs could be effectively oxidized.

  11. Forsmark site investigation. Investigation of marine and lacustrine sediment in lakes. Field data 2003

    Energy Technology Data Exchange (ETDEWEB)

    Hedenstroem, Anna [SGU, Uppsala (Sweden)

    2003-04-01

    The aim of this activity is to describe the aerial and stratigraphical distribution of marine and lacustrine sediment i.e. sediment overlaying the glacial till and/or bedrock surface, in lakes in the Forsmark area. The investigation is carried out within areas where mapping of unconsolidated Quaternary deposits is presently carried out. Since small and shallow lakes cover a large part of the region, this work will give important information on the distribution and stratigraphy of sedimentary deposits not included in the regular mapping of unconsolidated Quaternary deposits within the site investigation programme. Samples were also collected for laboratory analyses of grain size distribution, mineralogical composition as well as the total content of C, N and S and calcium carbonate. The analyses will be carried out on selected samples of representative sedimentary units in order to characterise the chemical and physical properties of the unconsolidated deposits. The analytical data will be useful for the hydrogeological modelling and for models of the Quaternary evolution of the area. The mineralogical analyses of clay may provide information on the origin of the clay particles. One stratigraphic sequence from Lake Eckarfjaerden will be stored for later analyses, e.g. pollen analysis. This report includes field data from spring 2003. Together, the field data and the forthcoming results from the laboratory analyses will form the basis for construction of stratigraphical profiles to be presented in a following report in the fall 2003.

  12. Development and application of a marine sediment pore-water toxicity test using Ulva fasciata zoospores

    Science.gov (United States)

    Hooten, R.L.; Carr, R.S.

    1998-01-01

    An acute (96 h) pore-water toxicity test protocol using germination and growth of Ulva fasciata zoospores as endpoints was developed to test the toxicity of marine and estuarine sediment pore-water samples. Tests with an organic toxicant (sodium dodecyl sulfate; SDS), three metals (Cd, Cu, and Zn), and ammonia (NH3) were conducted to determine zoospore sensitivity. Zoospore germination and gametophyte growth were as sensitive to SDS as sea urchin (Arbacia punctulata) fertilization and embryological development. Zoospore sensitivity to metals was greater than or comparable to that of adult macroalgae. Zoospores were less sensitive to NH3 than were other commonly used toxicity test organisms. Test results using this algal assay with sediment pore-water samples with high NH3 concentrations were compared with results from sea urchin fertilization and embryological development tests for the same samples. Ulva fasciata zoospore germination was not affected by samples with high NH3 concentrations that were toxic in both sea urchin tests. Zoospore tolerance of NH3 and sensitivity to other contaminants indicate that their response may be useful in toxicity identification evaluation studies with pore-water samples that contain high concentrations of unionized NH3.

  13. MOSAIC: An organic geochemical and sedimentological database for marine surface sediments

    Science.gov (United States)

    Tavagna, Maria Luisa; Usman, Muhammed; De Avelar, Silvania; Eglinton, Timothy

    2015-04-01

    Modern ocean sediments serve as the interface between the biosphere and the geosphere, play a key role in biogeochemical cycles and provide a window on how contemporary processes are written into the sedimentary record. Research over past decades has resulted in a wealth of information on the content and composition of organic matter in marine sediments, with ever-more sophisticated techniques continuing to yield information of greater detail and as an accelerating pace. However, there has been no attempt to synthesize this wealth of information. We are establishing a new database that incorporates information relevant to local, regional and global-scale assessment of the content, source and fate of organic materials accumulating in contemporary marine sediments. In the MOSAIC (Modern Ocean Sediment Archive and Inventory of Carbon) database, particular emphasis is placed on molecular and isotopic information, coupled with relevant contextual information (e.g., sedimentological properties) relevant to elucidating factors that influence the efficiency and nature of organic matter burial. The main features of MOSAIC include: (i) Emphasis on continental margin sediments as major loci of carbon burial, and as the interface between terrestrial and oceanic realms; (ii) Bulk to molecular-level organic geochemical properties and parameters, including concentration and isotopic compositions; (iii) Inclusion of extensive contextual data regarding the depositional setting, in particular with respect to sedimentological and redox characteristics. The ultimate goal is to create an open-access instrument, available on the web, to be utilized for research and education by the international community who can both contribute to, and interrogate the database. The submission will be accomplished by means of a pre-configured table available on the MOSAIC webpage. The information on the filled tables will be checked and eventually imported, via the Structural Query Language (SQL), into

  14. An examination of the factors controlling mercury methylation in sulfidic coastal marine sediments

    Science.gov (United States)

    Mason, R. P.; Hollweg, T. A.; Schartup, A.; Gilmour, C. C.

    2010-12-01

    The methylation of mercury (Hg) is an important step in the biogeochemical cycling and bioaccumulation of methylmercury in marine organisms. The rate of methylation is controlled by both the chemical bioavailability of Hg to methylating organisms and their activity. It is known that methylation rate decreases in sulfidic environments, especially in marine waters, but the exact mechanisms accounting for this decrease are not well-known. Modeling studies suggest that adsorption and precipitation reactions in the presence of sulfide decrease the fraction that is considered bioavailable Hg but current models predict an increase in porewater concentration at high sulfide levels, which is contrary to field observations. We have therefore focused on ascertaining why the models overestimate dissolved Hg at high sulfide levels. We have developed models that incorporate interactions between Hg, dissolved and particulate sulfide (both FeS and pyrite) and including interactions in the presence of elemental sulfur (i.e the formation of Hg-polysulfide complexes). Additionally, we are incorporating data from our studies examining the interactions between Hg and organic matter extracted from various marine ecosystems. We compare our model results, through correlation and geochemical modeling, with data from studies in the Chesapeake Bay and associated shelf and slope, and test the sensitivity of the model to the various dissolved and solid phase interactions, and the role of solid phase organic carbon and organic sulfur content in influencing the strength of partitioning. A geochemical model will be presented describing how sediment redox status influences the strength of Hg partitioning, the dissolved speciation and we will compare measured Hg methylation rate constants with our predictions of porewater bioavailable Hg concentration.

  15. Deep-Sea, Deep-Sequencing: Metabarcoding Extracellular DNA from Sediments of Marine Canyons.

    Directory of Open Access Journals (Sweden)

    Magdalena Guardiola

    Full Text Available Marine sediments are home to one of the richest species pools on Earth, but logistics and a dearth of taxonomic work-force hinders the knowledge of their biodiversity. We characterized α- and β-diversity of deep-sea assemblages from submarine canyons in the western Mediterranean using an environmental DNA metabarcoding. We used a new primer set targeting a short eukaryotic 18S sequence (ca. 110 bp. We applied a protocol designed to obtain extractions enriched in extracellular DNA from replicated sediment corers. With this strategy we captured information from DNA (local or deposited from the water column that persists adsorbed to inorganic particles and buffered short-term spatial and temporal heterogeneity. We analysed replicated samples from 20 localities including 2 deep-sea canyons, 1 shallower canal, and two open slopes (depth range 100-2,250 m. We identified 1,629 MOTUs, among which the dominant groups were Metazoa (with representatives of 19 phyla, Alveolata, Stramenopiles, and Rhizaria. There was a marked small-scale heterogeneity as shown by differences in replicates within corers and within localities. The spatial variability between canyons was significant, as was the depth component in one of the canyons where it was tested. Likewise, the composition of the first layer (1 cm of sediment was significantly different from deeper layers. We found that qualitative (presence-absence and quantitative (relative number of reads data showed consistent trends of differentiation between samples and geographic areas. The subset of exclusively benthic MOTUs showed similar patterns of β-diversity and community structure as the whole dataset. Separate analyses of the main metazoan phyla (in number of MOTUs showed some differences in distribution attributable to different lifestyles. Our results highlight the differentiation that can be found even between geographically close assemblages, and sets the ground for future monitoring and conservation

  16. Metal release from contaminated estuarine sediment under pH changes in the marine environment.

    Science.gov (United States)

    Martín-Torre, M Camino; Payán, M Cruz; Verbinnen, Bram; Coz, Alberto; Ruiz, Gema; Vandecasteele, Carlo; Viguri, Javier R

    2015-04-01

    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. Leaching test results using seawater as leaching solution show a better neutralisation capacity giving slightly lower metal leaching concentrations than when using deionised water. The contaminated sediment shows a low base-neutralisation capacity (BNCpH 12 = -0.44 eq/kg for deionised water and BNCpH 12 = -1.38 eq/kg for seawater) but a high acid-neutralisation capacity when using deionised water (ANCpH 4 = 3.58 eq/kg) and seawater (ANCpH 4 = 3.97 eq/kg). Experimental results are modelled with the Visual MINTEQ geochemical software to predict metal release from sediment using both leaching liquids. Surface adsorption to iron- and aluminium-(hydr)oxides was applied for all studied elements. The consideration of the metal-organic matter binding through the NICA-Donnan model and Stockholm Humic Model for lead and copper, respectively, improves the former metal release prediction. Modelled curves can be useful for the environmental impact assessment of seawater acidification due to its match with the experimental values.

  17. Evaluation of reference genes for real-time quantitative PCR in the marine flavobacterium Zobellia galactanivorans.

    Science.gov (United States)

    Thomas, François; Barbeyron, Tristan; Michel, Gurvan

    2011-01-01

    The marine bacteria Zobellia galactanivorans is an emerging model microorganism for the bioconversion of algal polysaccharides. The sequence analysis of its genome opens the way to in-depth gene expression analysis, such as reverse transcription quantitative PCR (RT-qPCR) studies. The selection and validation of reference genes are a mandatory first step for the accurate quantification of transcripts. We selected fourteen candidate reference genes belonging to distinct pathways, namely replication, transcription, translation, citric acid cycle, amino acid, nucleotide and dihydrofolate metabolisms, and peptidoglycan, FMN and aromatic compounds synthesis. We quantified their expression by RT-qPCR in various culture conditions corresponding to different temperatures, carbon sources or stresses. The applications geNorm and Normfinder allowed ranking the genes according to their stability and gave concordant results. We found that the geometric average of the expression of glyA, icdA and gmkA can be confidently used to normalize the transcript abundance of genes of interest. In conclusion, this work provides a reliable procedure for gene expression analysis in the flavobacterium Z. galactanivorans and a validated set of reference genes to be used in future transcriptomics approaches. The strategy developed could also be the starting point for similar studies in other members of the Flavobacteria class.

  18. The Deposition and Accumulation of Microplastics in Marine Sediments and Bottom Water from the Irish Continental Shelf.

    Science.gov (United States)

    Martin, Jake; Lusher, Amy; Thompson, Richard C; Morley, Audrey

    2017-09-07

    Microplastics are widely dispersed throughout the marine environment. An understanding of the distribution and accumulation of this form of pollution is crucial for gauging environmental risk. Presented here is the first record of plastic contamination, in the 5 mm-250 μm size range, of Irish continental shelf sediments. Sixty-two microplastics were recovered from 10 of 11 stations using box cores. 97% of recovered microplastics were found to reside shallower than 2.5 cm sediment depth, with the area of highest microplastic concentration being the water-sediment interface and top 0.5 cm of sediments (66%). Microplastics were not found deeper than 3.5 ± 0.5 cm. These findings demonstrate that microplastic contamination is ubiquitous within superficial sediments and bottom water along the western Irish continental shelf. Results highlight that cores need to be at least 4-5 cm deep to quantify the standing stock of microplastics within marine sediments. All recovered microplastics were classified as secondary microplastics as they appear to be remnants of larger items; fibres being the principal form of microplastic pollution (85%), followed by broken fragments (15%). The range of polymer types, colours and physical forms recovered suggests a variety of sources. Further research is needed to understand the mechanisms influencing microplastic transport, deposition, resuspension and subsequent interactions with biota.

  19. Seasonality and depth distribution of the abundance and activity of ammonia oxidizing microorganisms in marine coastal sediments (North Sea

    Directory of Open Access Journals (Sweden)

    Yvonne Antonia Lipsewers

    2014-09-01

    Full Text Available Microbial processes such as nitrification and anaerobic ammonium oxidation (anammox are important for nitrogen cycling in marine sediments. Seasonal variations of archaeal and bacterial ammonia oxidizers (AOA and AOB and anammox bacteria, as well as the environmental factors affecting these groups, are not well studied. We have examined the seasonal and depth distribution of the abundance and potential activity of these microbial groups in coastal marine sediments of the southern North Sea. This was achieved by quantifying specific intact polar lipids (IPLs as well as the abundance and gene expression of their 16S rRNA gene, the ammonia monooxygenase subunit A (amoA gene of AOA and AOB, and the hydrazine synthase (hzsA gene of anammox bacteria. AOA, AOB and anammox bacteria were detected and transcriptionally active down to 12 cm sediment depth. In all seasons, the abundance of AOA was higher compared to the AOB abundance suggesting that AOA play a more dominant role in aerobic ammonia oxidation in these sediments. Anammox bacteria were abundant and active even in oxygenated and bioturbated parts of the sediment. The abundance of AOA and AOB was relatively stable with depth and over the seasonal cycle, while anammox bacteria abundance and transcriptional activity were highest in August. North Sea sediments thus seem to provide a common, stable, ecological niche for AOA, AOB and anammox bacteria.

  20. STUDY OF THE SEDIMENTATION TREND IN THE PROSPECTIVE AREA OF PORT OF MARINE CENTER, CIREBON BASED ON REMOTE SENSING DATA

    Directory of Open Access Journals (Sweden)

    Undang Hernawan

    2017-07-01

    Full Text Available A coastal zone is the interface between the land and water that influenced by both of them. Coastal dynamic is influenced by many factors from land and sea, such as sedimentation and current. In order to support marine facility, Marine Geological Institute of Indonesia (MGI plan to build a port. The prospective area is behind MGI office at Cirebon. This study use multi temporal remote sensing data in order to observe trend of coastline change around MGI. Based on the interpretation of the data, there are sedimentation around the MGI water and abrasion due to the presence of Kejawanan’s jetty and Kalijaga River. The result also shows that the current in this region is moving from southeast to northwest. The presence of the Kejawanan’s jetty stymies the movement of sediment. The sediment which is normally moving to the north of the jetty is then trapped on the south side of the structure, so that the sediment precipitates in this region and makes it as the active region of sedimentation and accretion. The presence mangrove conduces to support sedimentation speed and accretion at this region, because of his function as the catchment area. Abrasion occurs in the eastern part of MGI office at the Kalijaga river mouth within the bay. The Kalijaga River mouth is predicted to be the primary source of sedimentation in this area. The coastline change caused by sedimentation will be continuing as long as it is supplied by the sediment. The direction of the sedimentation is parallel to the jetty and it forms ellipsoid, with the sedimentation/accretion region is behind MGI office. The abrasion area is found in Kalijaga River mouth and a small area beside Kalijaga River. In order to build a port, we have to consider this sedimentation process. One of the alternatives to build the port is to make a quay pile model which gives way the current to pass through the other side of the port. Another alternative is to build the port as a pond model but

  1. ACOUSTICAL IMAGING AND MECHANICAL PROPERTIES OF SOFT ROCK AND MARINE SEDIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Thurman E. Scott, Jr., Ph.D.; Younane Abousleiman, Ph.D.; Musharraf Zaman, Ph.D., P.E.

    2001-07-01

    Mechanically weak formations, such as chalks, high porosity sandstones, and marine sediments, pose significant problems for oil and gas operators. Problems such as compaction, subsidence, and loss of permeability can affect reservoir production operations. For example, the unexpected subsidence of the Ekofisk chalk in the North Sea required over one billion dollars to re-engineer production facilities to account for losses created during that compaction (Sulak 1991). Another problem in weak formations is that of shallow water flows (SWF). Deep water drilling operations sometimes encounter cases where the marine sediments, at shallow depths just below the seafloor, begin to uncontrollably flow up and around the drill pipe. SWF problems created a loss of $150 million for the Ursa development project in the U.S. Gulf Coast SWF (Furlow 1998a,b; 1999a,b). The goal of this project is to provide a database on both the rock mechanical properties and the geophysical properties of weak rocks and sediments. These could be used by oil and gas companies to detect, evaluate, and alleviate potential production and drilling problems. The results will be useful in, for example, pre-drill detection of events such as SWF's by allowing a correlation of seismic data (such as hazard surveys) to rock mechanical properties. The data sets could also be useful for 4-D monitoring of the compaction and subsidence of an existing reservoir and imaging the zones of damage. During the second quarter of the project the research team has: (1) completed acoustic sensor construction, (2) conducted reconnaissance tests to map the deformational behaviors of the various rocks, (3) developed a sample assembly for the measurement of dynamic elastic and poroelastic parameters during triaxial testing, and (4) conducted a detailed review of the scientific literature and compiled a bibliography of that review. During the first quarter of the project the research team acquired several rock types for

  2. A miniature Marine Aerosol Reference Tank (miniMART) as a compact breaking wave analogue

    Science.gov (United States)

    Stokes, M. Dale; Deane, Grant; Collins, Douglas B.; Cappa, Christopher; Bertram, Timothy; Dommer, Abigail; Schill, Steven; Forestieri, Sara; Survilo, Mathew

    2016-09-01

    In order to understand the processes governing the production of marine aerosols, repeatable, controlled methods for their generation are required. A new system, the miniature Marine Aerosol Reference Tank (miniMART), has been designed after the success of the original MART system, to approximate a small oceanic spilling breaker by producing an evolving bubble plume and surface foam patch. The smaller tank utilizes an intermittently plunging jet of water produced by a rotating water wheel, into an approximately 6 L reservoir to simulate bubble plume and foam formation and generate aerosols. This system produces bubble plumes characteristic of small whitecaps without the large external pump inherent in the original MART design. Without the pump it is possible to easily culture delicate planktonic and microbial communities in the bulk water during experiments while continuously producing aerosols for study. However, due to the reduced volume and smaller plunging jet, the absolute numbers of particles generated are approximately an order of magnitude less than in the original MART design.

  3. Combining contamination indexes, sediment quality guidelines and multivariate data analysis for metal pollution assessment in marine sediments of Cienfuegos Bay, Cuba.

    Science.gov (United States)

    Peña-Icart, Mirella; Pereira-Filho, Edenir Rodrigues; Lopes Fialho, Lucimar; Nóbrega, Joaquim A; Alonso-Hernández, Carlos; Bolaños-Alvarez, Yoelvis; Pomares-Alfonso, Mario S

    2017-02-01

    The purpose of the present work was to combine several tools for assessing metal pollution in marine sediments from Cienfuegos Bay. Fourteen surface sediments collected in 2013 were evaluated. Concentrations of As, Cu, Ni, Zn and V decreased respect to those previous reported. The metal contamination was spatially distributed in the north and south parts of the bay. According to the contamination factor (CF) enrichment factor (EF) and index of geoaccumulation (Igeo), Cd and Cu were classified in that order as the most contaminated elements in most sediment. Comparison of the total metal concentrations with the threshold (TELs) and probable (PELs) effect levels in sediment quality guidelines suggested a more worrisome situation for Cu, of which concentrations were occasional associated with adverse biological effects in thirteen sediments, followed by Ni in nine sediments; while adverse effects were rarely associated with Cd. Probably, Cu could be considered as the most dangerous in the whole bay because it was classified in the high contamination levels by all indexes and, simultaneously, associated to occasional adverse effects in most samples. Despite the bioavailability was partially evaluated with the HCl method, the low extraction of Ni (<3% in all samples) and Cu (<55%, except sample 3) and the relative high extraction of Cd (50% or more, except sample 14) could be considered as an attenuating (Ni and Cu) or increasing (Cd) factor in the risk assessment of those element. Copyright © 2016. Published by Elsevier Ltd.

  4. Survival, Reproduction and Growth of the Marine Amphipod, Leptocheirus plumulosus, Following Laboratory Exposure to Copper-Spiked Sediment.

    Science.gov (United States)

    Ward, Timothy J; Gaertner, Karin E; Gorsuch, Joseph W; Call, Daniel J

    2015-10-01

    Leptocheirus plumulosus was exposed for 28 days to Cu-spiked sediment at mean concentrations ranging from 44.4 to 605 mg Cu/kg dry sediment in a sediment/water test system designed to simulate natural conditions. The NOEC (no observed effect concentration)-LOEC (lowest observed effect concentration) range for the most sensitive endpoint of growth was 199-414 mg Cu/kg sediment. An IC50 for reproduction was estimated at 187 mg Cu/kg sediment. Mean Cu concentrations in pore water (PW) where significant effects were observed were 25.8 and 59.0 µg/L, while their respective concentrations in overlying water (OW) were 22.1 and 28.0 µg Cu/L. Copper concentrations were ≤19.1 and <16.6 µg/L in PW and OW, respectively, at lower exposures where effects were not evident. Concentrations of Cu in marine sediment lower than sediment quality guidelines based on geochemical factors of acid volatile sulfide, organic carbon content (f OC), and sediment grain size (i.e., silt + clay) would appear not to result in adverse effects toward L. plumulosus.

  5. Modelling the cohesive sediment transport in the marine environment: the case of Thermaikos Gulf

    Directory of Open Access Journals (Sweden)

    Y. N. Krestenitis

    2007-01-01

    Full Text Available The transport of fine-grained sediments in the marine environment entails risks of pollutant intrusions from substances absorbed onto the cohesive flocks' surface, gradually released to the aquatic field. These substances include nutrients such as nitrate, phosphate and silicate compounds from drainage from fertilization of adjacent cultivated areas that enter the coastal areas through rivers and streams, or trace metals as remainders from urban and industrial activities. As a consequence, knowledge on the motion and distribution of sediment particles coming from a given pollutant source is expected to provide the 'bulk' information on pollutant distribution, necessary for determining the region of influence of the source and to estimate probable trophic levels of the seawater and potential environmental risks. In that aim a numerical model has been developed to predict the fate of the sediments introduced to the marine environment from different pollution sources, such as river outflows, erosion of the seabed, aeolian transported material and drainage systems. The proposed three-dimensional mathematical model is based on the particle tracking method, according to which matter concentration is expressed by particles, each representing a particular amount of sedimentary mass, passively advected and dispersed by the currents. The processes affecting characteristics and propagation of sedimentary material in the marine environment, incorporated in the parameterization, apart from advection and dispersion, include cohesive sediment and near-bed processes. The movement of the particles along with variations in sedimentary characteristics and state, carried by each particle as personal information, are traced with time. Specifically, concerning transport processes, the local seawater velocity and the particle's settling control advection, whereas the random Brownian motion due to turbulence simulates turbulent diffusion. The

  6. Modelling the cohesive sediment transport in the marine environment: the case of Thermaikos Gulf

    Science.gov (United States)

    Krestenitis, Y. N.; Kombiadou, K. D.; Savvidis, Y. G.

    2007-02-01

    The transport of fine-grained sediments in the marine environment entails risks of pollutant intrusions from substances absorbed onto the cohesive flocks' surface, gradually released to the aquatic field. These substances include nutrients such as nitrate, phosphate and silicate compounds from drainage from fertilization of adjacent cultivated areas that enter the coastal areas through rivers and streams, or trace metals as remainders from urban and industrial activities. As a consequence, knowledge on the motion and distribution of sediment particles coming from a given pollutant source is expected to provide the 'bulk' information on pollutant distribution, necessary for determining the region of influence of the source and to estimate probable trophic levels of the seawater and potential environmental risks. In that aim a numerical model has been developed to predict the fate of the sediments introduced to the marine environment from different pollution sources, such as river outflows, erosion of the seabed, aeolian transported material and drainage systems. The proposed three-dimensional mathematical model is based on the particle tracking method, according to which matter concentration is expressed by particles, each representing a particular amount of sedimentary mass, passively advected and dispersed by the currents. The processes affecting characteristics and propagation of sedimentary material in the marine environment, incorporated in the parameterization, apart from advection and dispersion, include cohesive sediment and near-bed processes. The movement of the particles along with variations in sedimentary characteristics and state, carried by each particle as personal information, are traced with time. Specifically, concerning transport processes, the local seawater velocity and the particle's settling control advection, whereas the random Brownian motion due to turbulence simulates turbulent diffusion. The vertical stratification of the water-column is

  7. Modelling the cohesive sediment transport in the marine environment: the case of Thermaikos Gulf

    Directory of Open Access Journals (Sweden)

    Y. N. Krestenitis

    2006-07-01

    Full Text Available The transport of fine-grained sediments in the marine environment entails risks of pollutant intrusions from substances absorbed onto the cohesive flocks' surface, gradually released to the aquatic field. These substances include nutrients such as nitrate, phosphate and silicate compounds from drainage from fertilization of adjacent cultivated areas that enter the coastal areas through rivers and streams, or trace metals as remainders from urban and industrial activities. As a consequence, knowledge on the motion and distribution of sediment particles coming from a given pollutant source is expected to provide the ''bulk'' information on pollutant distribution, necessary for determining the region of influence of the source and to estimate probable trophic levels of the seawater and potential environmental risks. In that aim a numerical model has been developed to predict the fate of the sediments introduced to the marine environment from different pollution sources, such as river outflows, erosion of the seabed, aeolian transported material and drainage systems.

    The proposed three-dimensional mathematical model is based on the particle tracking method, according to which matter concentration is expressed by particles, each representing a particular amount of sedimentary mass, passively advected and dispersed by the currents. The processes affecting characteristics and propagation of sedimentary material in the marine environment, incorporated in the parameterization, apart from advection and dispersion, include cohesive sediment and near-bed processes. The movement of the particles along with variations in sedimentary characteristics and state, carried by each particle as personal information, are traced with time. Specifically, concerning transport processes, the local seawater velocity and the particle's settling control advection, whereas the random Brownian motion due to turbulence simulates turbulent

  8. Where Has All the Oil Gone? The use of trace metals as potential indicators of oil contamination in marine sediments and beach sands

    Science.gov (United States)

    Roeder, T. K.; Hastings, D. W.; Holzinger, C.; Playle, E.; Brooks, G.; Huettel, M. H.; Kostka, J. E.; Larson, R. A.; Flower, B. P.

    2011-12-01

    We report initial results to determine if select trace metals are effective indicators for the magnitude and spatial extent of Deep Water Horizon (DWH) oil contamination in Gulf of Mexico marine sediments and beach sands. Since crude oil is known to have elevated concentrations of nickel and vanadium, contamination can be detected even after the degradation of oil by measuring enrichment of these metals within marine sediments and beach sands. A sample of crude oil from the Macondo Prospect, source of the Deepwater Horizon (DWH) oil spill, was fully digested and analyzed by inductively coupled plasma mass spectrometry (ICP-MS) at the College of Marine Science, University of South Florida. Results indicate the crude oil is enriched in nickel, vanadium, and cobalt, with concentrations of 0.86 ppm, 2.76 ppm, and 84 ppb, respectively. With this known trace metal enrichment in DWH oil, Gulf of Mexico marine sediments from 400 and 1100m water depth near DeSoto Canyon and beach sands from Pensacola, FL were examined for enrichment of V, Ni, and Co. Both marine sediment and beach sand samples were partially digested with HNO3 before analysis via ICP-MS. With marine sediments, the visually contaminated layer at or near the surface typically exhibited an enrichment in Ni, V, and Co compared to the pristine control sediments. Vanadium and nickel enrichment in marine sediments varied from 10 to 32% and 0 to 22%, respectively. Visible contamination in beach sands was found between 20-60cm beneath the surface and, likewise, showed Ni, V, and Co enrichment up to 33%, 45%, and 100%. This data shows that enrichment of V, Ni, and Co in marine sediments and beach sands may be an effective proxy for contamination even after the degradation of oil. Marine sediments and beach sands will continue to be monitored for trace metal enrichment in an effort to assess the continuing impacts of the DWH spill on the Gulf of Mexico.

  9. Plutonium behavior during the early diagenesis of marine sediments: applications to two marine environments labelled by radionuclides released from reprocessing plants; Etude du comportement du plutonium au cours de la diagenese precoce des sediments marins: applications a deux environnements marins marques par les rejets issus d'usines de retraitement de combustibles uses

    Energy Technology Data Exchange (ETDEWEB)

    Gouzy, A

    2004-12-15

    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)

  10. Development of a blind reference sediment for use in upper Mississippi River and other sediment quality studies

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Upper Mississippi River has a history of abuse and neglect by Man, resulting in the past contamination of its sediments by heavy metals and organic compounds...

  11. Spatial and temporal distribution and pollution assessment of trace metals in marine sediments in Oyster Bay, NSW, Australia.

    Science.gov (United States)

    Alyazichi, Yasir M; Jones, Brian G; McLean, Errol

    2015-01-01

    The disposal of untreated urban and industrial wastewater has a deleterious effect on both the water and sediment quality of Oyster Bay located in south Sydney, Australia. The present investigation was undertaken to evaluate the potential pollution of marine sediments in Oyster Bay. The results of metals were compared with adverse biological effect values effect range low (ERL) and effect range median (ERM). Spatial distribution of trace metals was estimated by applying geographic information system. The results indicated that the sediments were polluted with Cu, Zn, As and Pb, which exceeded ERL levels. However, these metals were still below ERM values, and other metals Cr and Ni were below ERL. Moreover, the highest concentrations of metals were around discharge points and in the inner bay. Further, trace metals could be attributed to human activities within the bay as they declined in concentrations with increasing sediment depth.

  12. Setting limits for acceptable change in sediment particle size composition: testing a new approach to managing marine aggregate dredging.

    Science.gov (United States)

    Cooper, Keith M

    2013-08-15

    A baseline dataset from 2005 was used to identify the spatial distribution of macrofaunal assemblages across the eastern English Channel. The range of sediment composition found in association with each assemblage was used to define limits for acceptable change at ten licensed marine aggregate extraction areas. Sediment data acquired in 2010, 4 years after the onset of dredging, were used to assess whether conditions remained within the acceptable limits. Despite the observed changes in sediment composition, the composition of sediments in and around nine extraction areas remained within pre-defined acceptable limits. At the tenth site, some of the observed changes within the licence area were judged to have gone beyond the acceptable limits. Implications of the changes are discussed, and appropriate management measures identified. The approach taken in this study offers a simple, objective and cost-effective method for assessing the significance of change, and could simplify the existing monitoring regime. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Stable carbon isotope ratios of archaeal GDGTs in the marine water column and surface sediments

    Science.gov (United States)

    Pearson, A.; Hurley, S.; Close, H. G.; Jasper, C. E.

    2016-12-01

    Archaeal glycerol dibiphytanyl glycerol tetraether (GDGT) lipids are ubiquitous throughout the marine environment and are preserved in sediments and sedimentary rocks on million-year timescales. Variations in the number of ring-containing GDGT isomers in sediments correlate with differences in overlying sea surface temperatures, a relationship formalized in the TEX86 paleotemperature proxy. Ammonia-oxidizing Thaumarchaeota are believed to be the major sources of these GDGTs, implying that the greatest production and export of GDGTs from the water column should be associated with the maximum expression of ammonia monooxygenase (amoA) genes and maximum number of thaumarchaeal cells, both of which occur in the subsurface NO2- maximum near a depth of ca. 80-250 m. To examine the relationship between production and export of GDGTs from the water column, we measured the concentrations and δ13C values of GDGTs in suspended particulate matter (SPM) of the western South Atlantic Ocean and compared them to values from pure thaumarchaeal cultures and from available sediment core-tops from other locations. Thaumarchaeota are believed to fix the majority of their carbon directly from dissolved inorganic carbon (DIC). However, both the SPM and core-top δ13C values in some cases are moderately more 13C-depleted than would be predicted based on the 13C content of local DIC and the previously-published biosynthetic isotope fractionation (ɛ). This indicates that the average metabolism of the planktonic archaeal community either is mixotrophic (≥ 25% organic carbon assimilation) or that the published ɛ value for the model organism Nitrosopumilus maritimus may not be representative of the total autotrophic community. In addition to this offset, δ13C values of GDGTs in SPM inversely mirror DIC profiles, with lowest values in the nitrite maximum and higher values in the deeper water column, similar to the overall trends for bulk SPM. Finally, while individual GDGTs in SPM samples

  14. Marine Microbial Gene Abundance and Community Composition in Response to Ocean Acidification and Elevated Temperature in Two Contrasting Coastal Marine Sediments.

    Science.gov (United States)

    Currie, Ashleigh R; Tait, Karen; Parry, Helen; de Francisco-Mora, Beatriz; Hicks, Natalie; Osborn, A Mark; Widdicombe, Steve; Stahl, Henrik

    2017-01-01

    Marine ecosystems are exposed to a range of human-induced climate stressors, in particular changing carbonate chemistry and elevated sea surface temperatures as a consequence of climate change. More research effort is needed to reduce uncertainties about the effects of global-scale warming and acidification for benthic microbial communities, which drive sedimentary biogeochemical cycles. In this research, mesocosm experiments were set up using muddy and sandy coastal sediments to investigate the independent and interactive effects of elevated carbon dioxide concentrations (750 ppm CO2) and elevated temperature (ambient +4°C) on the abundance of taxonomic and functional microbial genes. Specific quantitative PCR primers were used to target archaeal, bacterial, and cyanobacterial/chloroplast 16S rRNA in both sediment types. Nitrogen cycling genes archaeal and bacterial ammonia monooxygenase (amoA) and bacterial nitrite reductase (nirS) were specifically targeted to identify changes in microbial gene abundance and potential impacts on nitrogen cycling. In muddy sediment, microbial gene abundance, including amoA and nirS genes, increased under elevated temperature and reduced under elevated CO2 after 28 days, accompanied by shifts in community composition. In contrast, the combined stressor treatment showed a non-additive effect with lower microbial gene abundance throughout the experiment. The response of microbial communities in the sandy sediment was less pronounced, with the most noticeable response seen in the archaeal gene abundances in response to environmental stressors over time. 16S rRNA genes (amoA and nirS) were lower in abundance in the combined stressor treatments in sandy sediments. Our results indicated that marine benthic microorganisms, especially in muddy sediments, are susceptible to changes in ocean carbonate chemistry and seawater temperature, which ultimately may have an impact upon key benthic biogeochemical cycles.

  15. Marine Microbial Gene Abundance and Community Composition in Response to Ocean Acidification and Elevated Temperature in Two Contrasting Coastal Marine Sediments

    Directory of Open Access Journals (Sweden)

    Ashleigh R. Currie

    2017-08-01

    Full Text Available Marine ecosystems are exposed to a range of human-induced climate stressors, in particular changing carbonate chemistry and elevated sea surface temperatures as a consequence of climate change. More research effort is needed to reduce uncertainties about the effects of global-scale warming and acidification for benthic microbial communities, which drive sedimentary biogeochemical cycles. In this research, mesocosm experiments were set up using muddy and sandy coastal sediments to investigate the independent and interactive effects of elevated carbon dioxide concentrations (750 ppm CO2 and elevated temperature (ambient +4°C on the abundance of taxonomic and functional microbial genes. Specific quantitative PCR primers were used to target archaeal, bacterial, and cyanobacterial/chloroplast 16S rRNA in both sediment types. Nitrogen cycling genes archaeal and bacterial ammonia monooxygenase (amoA and bacterial nitrite reductase (nirS were specifically targeted to identify changes in microbial gene abundance and potential impacts on nitrogen cycling. In muddy sediment, microbial gene abundance, including amoA and nirS genes, increased under elevated temperature and reduced under elevated CO2 after 28 days, accompanied by shifts in community composition. In contrast, the combined stressor treatment showed a non-additive effect with lower microbial gene abundance throughout the experiment. The response of microbial communities in the sandy sediment was less pronounced, with the most noticeable response seen in the archaeal gene abundances in response to environmental stressors over time. 16S rRNA genes (amoA and nirS were lower in abundance in the combined stressor treatments in sandy sediments. Our results indicated that marine benthic microorganisms, especially in muddy sediments, are susceptible to changes in ocean carbonate chemistry and seawater temperature, which ultimately may have an impact upon key benthic biogeochemical cycles.

  16. Evaluation of Near-Surface Gases in Marine Sediments to Assess Subsurface Petroleum Gas Generation and Entrapment

    Directory of Open Access Journals (Sweden)

    Michael A. Abrams

    2017-05-01

    Full Text Available Gases contained within near-surface marine sediments can be derived from multiple sources: shallow microbial activity, thermal cracking of organic matter and inorganic materials, or magmatic-mantle degassing. Each origin will display a distinctive hydrocarbon and non-hydrocarbon composition as well as compound-specific isotope signature and thus the interpretation of origin should be relatively straightforward. Unfortunately, this is not always the case due to in situ microbial alteration, non-equilibrium phase partitioning, mixing, and fractionation related to the gas extraction method. Sediment gases can reside in the interstitial spaces, bound to mineral or organic surfaces and/or entrapped in carbonate inclusions. The interstitial sediment gases are contained within the sediment pore space, either dissolved in the pore waters (solute or as free (vapour gas. The bound gases are believed to be attached to organic and/or mineral surfaces, entrapped in structured water or entrapped in authigenic carbonate inclusions. The purpose of this paper is to provide a review of the gas types found within shallow marine sediments and examine issues related to gas sampling and extraction. In addition, the paper will discuss how to recognise mixing, alteration and fractionation issues to best interpret the seabed geochemical results and determine gas origin to assess subsurface petroleum gas generation and entrapment.

  17. Distribution and generic composition of culturable marine actinomycetes from the sediments of Indian continental slope of Bay of Bengal

    Science.gov (United States)

    Das, Surajit; Lyla, P. S.; Ajmal Khan, S.

    2008-05-01

    Actinomycetes population from continental slope sediment of the Bay of Bengal was studied. Samples were collected during two voyages of FORV Sagar Sampada in 2004 (May-June) and 2005 (July) respectively from 11 transects (each transect had ca. 200 m, 500 m, and 1 000 m depth stations). The physicochemical parameters of overlying water, and sediment samples were also recorded. The actinomycete population ranged from 5.17 to 51.94 CFU/g dry sediment weight and 9.38 to 45.22 CFU/g dry sediment weight during the two cruises respectively. No actinomycete colony was isolated from stations in 1 000 m depth. Two-way analysis of variance showed significant variation among stations (ANOVA two-way, P0.05). Three actinomycetes genera were identified. Streptomyces was found to be the dominating one in both the cruises, followed by Micromonospora, and Actinomyces. The spore of Streptomyces isolates showed the abundance in spiral spore chain. Spore surface was smooth. Multiple regression analysis revealed that the influencing physico-chemical factors were sediment pH, sediment temperature, TOC, porosity, salinity, and pressure. The media used in the present study was prepared with seawater. Thus, they may represent an autochthonous marine flora and deny the theory of land runoff carriage into the sea for adaptation to the salinity of the seawater and sediments.

  18. Shifts in Microbial Community Structure with Changes in Cathodic Potential in Marine Sediment Microcosms

    Science.gov (United States)

    Lam, B. R.; Rowe, A. R.; Nealson, K. H.

    2014-12-01

    Microorganisms comprise more than 90% of the biomass of the ocean. Their ability to thrive and survive in a wide range of environments from oligotrophic waters to the deep subsurface stems from the great metabolic versatility that exists among them. This metabolic versatility has further expanded with the discovery of extracellular electron transport (EET). EET is the capability of microorganisms to transfer electrons to and from insoluble substrates outside of the cell. Much of what is known about EET comes from studies of model metal reducing microorganisms in the groups Shewanellaceae and Geobacteraceae. However, EET is not limited to these metal reducing microorganisms, and may play a large role in the biogeochemical cycling of several elements. We have developed an electrochemical culturing technique designed to target microorganisms with EET ability and tested these methods in marine sediments. The use of electrodes allows for greater control and quantification of electrons flowing to insoluble substrates as opposed to insoluble substrates such as minerals that are often difficult to measure. We have recently shown that poising electrodes at different redox potentials will enrich for different microbial groups and thus possible metabolisms. In marine sediment microcosms, triplicate electrodes were poised at different cathodic (electron donating) potentials (-300, -400, -500 and -600 mV) and incubated for eight weeks. Community analysis of the 16S rRNA revealed that at lower negative potentials (-500 and -600 mV), more sulfate reducing bacteria in the class Deltaproteobacteria were enriched in comparison to the communities at -300 and -400 mV being dominated by microorganisms within Alphaproteobacteria, Gammaproteobacteria, and Clostridia. This can be explained by sulfate (abundant in seawater) becoming a more energetically favorable electron acceptor with lower applied potentials. In addition, communities at higher potentials showed greater enrichment of the

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

    Institute of Scientific and Technical Information of China (English)

    Sudha S; Masilamani Selvam M

    2012-01-01

    To investigate the cytotoxic activity of actinomycete isolated from marine sediment. Methods: In the present study the DNA was isolated and the ITS region of 16s rRNA was amplified by polymerase chain reaction, using two universal bacterial primers, 1492R (5′-GGTTACCTTGTTAC GACTT-3′) and Eubac27F (5′-AGAGTTTGATCCTGGCTC AG-3′). The amplified products were purified using TIANgel mini purification kit, ligated to MD18-T simple vector (TaKaRa), and transformed into competent cells of Escherichia coli DH5α. 16S rRNA gene fragment was sequenced using forward primer M13F (-47) and reverse primer M13R (-48). Blast search sequence similarity was found against the existing non-redundant nucleotide sequence database thus, identified as Streptomyces sp SU, Streptomyces rubralavandulae strain SU1, Streptomyces cacaoi strain SU2, Streptomyces cavourensis strain SU3, Streptomyces avidinii strain SU4, Streptomyces globisporus strain SU5, Streptomyces variabilis strain SU6, Streptomycescoelicolor strain SU 7. Among the eight identified isolates, one actinomycete Streptomyces avidinii strain SU4 was selected for further study. Results: Crude extract of the actinomycete isolate exhibited IC50 in 64.5 μg against Hep-2 cell line, 250 μg in VERO cell line. This value is very close to the criteria of cytotoxicity activity for the crude extracts, as established by the American National Cancer Institute (NCI) is in IC50 < 30 μg /mL. The GC MS analysis showed that the active principle might be 1,2-benzenedicarboxylic acid, bis(2-methylpropyl) ester (12.17%), isooctyl phthalate (15.29%) with the retention time 15.642 and 21.612, respectively. Conclusions: 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

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

    Institute of Scientific and Technical Information of China (English)

    Sudha; S; Masilamani; Selvam; M

    2012-01-01

    Objective:To investigate the cytotoxic activity of actinomycete isolated from marine sediment.Methods:In the present study the DNA was isolated and the ITS region of 16s rRNA was amplified by polymerase chain reaction,using two universal bacterial primers,1492K(5’-GGTTACCTTG’TTAC GACTT-3’)and Eubac27F(5’-AGAGTTTGATCCTGGCTC AG-3’).The amplified products were purified using TIANgel mini purification kit,ligated to MD18-T simple vector(TaKaRa),and transformed into competent cells of Escherichia coli DH5α.16S rRNA gene fragment was sequenced using forward primer M13F(-47)and reverse primer M13R(-48).Blast search sequence similarity was found against the existing non-redundanl nucleotide sequence database thus,identified as Streptomyces sp SU,Streptomyces rubralavandulae strain SU1,Streptomyces cacaoi strain SU2,Streptomyces cavourensis strain SU3,Streptomyces avidinii strain SU4,Streptomyces globisporus strain SU5,Streptomyces variabilis strain SU6,Streptomyces coelicolor strain SU 7.Among the eight identified isolates,one actinomycete Streptomyces avidinii strain SU4 was selected for further study.Results:Crude extract of the actinomycete isolate exhibited IC50in 64.5μg against Hep-2 cell line,250μg in VERO cell line.This value is very close to the criteria of cytotoxicity activity for the crude extracts,as established by the American National Cancer Institute(NCI)is in IC50<30μg/mL.The CC MS analysis showed that the active principle might be 1,2-benzenedicarboxylic acid,bis(2-methylpropyl)ester(12.17%),isooctyl phthalate(15.29%)with the retention time 15.642 and 21.612,respectively.Conclusions: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

  1. Sediment thicknesses and holocene glacial marine sedimentation rates in three east Greenland fjords (ca. 68°N)

    Science.gov (United States)

    Andrews, J.T.; Milliman, John D.; Jennings, A.E.; Rynes, N.; Dwyer, J.

    1994-01-01

    We compared measured and estimated sediment budgets in heavily glaciated fjords in East Greenland. Mass balance calculations and regional glacio-climatic conditions suggest that the sediment flux to the seafloor in Kangerdlugssuaq and Nansen fjords should be dominated by iceberg rafting and not by the rain-out of suspended particulates in meltwater, as the glacier calving flux is estimated at 15 and $2 km^{3}/yr$, compared to meltwater volumes of 4.4 and $1.7 km^{3}/yr$, respectively. Gravity cores in the three fjords indicate that the uppermost 1-2.5 m of sediment consists of diamictons or fine-grained laminated muds. AMS radiocarbon dates on calcareous foramininfera or shells (16 total) indicate sedimentation rates of 110 to 340 cm/ka within the fjords over the last 1 ka, and 10-20 cm/ka during the Holecene on the inner and middle shelf. Annual sediment discharge is around $0.67 \\times 10^{6}$ tonnes/yr within the Kangerdlugssuaq Fjord and Trough system, which translates into an average basin-wide rate of denudation of 0.01 mm/yr (0.01 m/ka). Air gun and deep-towed (Huntec) seismic profiling was carried out in Kangerdlugssuaq and Nansen fjords, East Greenland, and showed that sediment fills averaged 500 and 350 m respectively; they consist primarily of acoustically stratified sediments. If the sediment fills are entirely Holocene in age then the required average sediment accumulation rates of 35-50 m/ka are an order of magnitude larger than the $^{14}C $controlled rates of the last 1-2 ka. This raises the possibility that fjord sediments may be by-passed and not always recycled during glacial advances; this will affect sedimentation rates on adjacent shelves and deep-sea areas during successive glaciations

  2. Variations of marine pore water salinity and chlorinity in Gulf of Alaska sediments (IODP Expedition 341)

    Science.gov (United States)

    März, Christian; Mix, Alan C.; McClymont, Erin; Nakamura, Atsunori; Berbel, Glaucia; Gulick, Sean; Jaeger, John; Schneider (LeVay), Leah

    2014-05-01

    Pore waters of marine sediments usually have salinities and chlorinities similar to the overlying sea water, ranging around 34-35 psu (Practical Salinity Units) and around 550 mM Cl-, respectively. This is because these parameters are conservative in the sense that they do not significantly participate in biogeochemical cycles. However, pore water studies carried out in the frame of the International Ocean Discovery Program (IODP) and its predecessors have shown that salinities and chlorinities of marine pore waters can substantially deviate from the modern bottom water composition in a number of environmental settings, and various processes have been suggested to explain these phenomena. Also during the recent IODP Expedition 341 that drilled five sites in the Gulf of Alaska (Northeast Pacific Ocean) from the deep Surveyor Fan across the continental slope to the glaciomarine shelf deposits, several occurrences of pore waters with salinities and chlorinities significantly different from respective bottom waters were encountered during shipboard analyses. At the pelagic Sites U1417 and U1418 (~4,200 and ~3,700 m water depth, respectively), salinity and chlorinity maxima occur around 20-50 m sediment depth, but values gradually decrease with increasing drilling depths (down to 30 psu in ~600 m sediment depth). While the pore water freshening at depth is most likely an effect of clay mineral dehydration due to increasing burial depth, the shallow salinity and chlorinity maxima are interpreted as relicts of more saline bottom waters that existed in the North Pacific during the Last Glacial Maximum (Adkins et al., 2002). In contrast, the glaciomarine slope and shelf deposits at Site U1419 to U1421 (~200 to 1,000 m water depth) are characterised by unexpectedly low salinitiy and chlorinity values (as low as 16 psu and 295 mM Cl-, respectively) already in very shallow sediment depths (~10 m), and their records do not show systematic trends with sediment depth. Freshening

  3. 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.

  4. Nitrogen and phosphorus treatment of marine wastewater by a laboratory-scale sequencing batch reactor with eco-friendly marine high-efficiency sediment.

    Science.gov (United States)

    Cho, Seonghyeon; Kim, Jinsoo; Kim, Sungchul; Lee, Sang-Seob

    2017-06-22

    We screened and identified a NH3-N-removing bacterial strain, Bacillus sp. KGN1, and a [Formula: see text] removing strain, Vibrio sp. KGP1, from 960 indigenous marine isolates from seawater and marine sediment from Tongyeong, South Korea. We developed eco-friendly high-efficiency marine sludge (eco-HEMS), and inoculated these marine bacterial strains into the marine sediment. A laboratory-scale sequencing batch reactor (SBR) system using the eco-HEMS for marine wastewater from land-based fish farms improved the treatment performance as indicated by 88.2% removal efficiency (RE) of total nitrogen (initial: 5.6 mg/L) and 90.6% RE of total phosphorus (initial: 1.2 mg/L) under the optimal operation conditions (food and microorganism (F/M) ratio, 0.35 g SCODCr/g mixed liquor volatile suspended solids (MLVSS)·d; dissolved oxygen (DO) 1.0 ± 0.2 mg/L; hydraulic retention time (HRT), 6.6 h; solids retention time (SRT), 12 d). The following kinetic parameters were obtained: cell yield (Y), 0.29 g MLVSS/g SCODCr; specific growth rate (µ), 0.06 d(-1); specific nitrification rate (SNR), 0.49 mg NH3-N/g MLVSS·h; specific denitrification rate (SDNR), 0.005 mg [Formula: see text]/g MLVSS·h; specific phosphorus uptake rate (SPUR), 0.12 mg [Formula: see text]/g MLVSS·h. The nitrogen- and phosphorus-removing bacterial strains comprised 18.4% of distribution rate in the microbial community of eco-HEMS under the optimal operation conditions. Therefore, eco-HEMS effectively removed nitrogen and phosphorus from highly saline marine wastewater from land-based fish farms with improving SNR, SDNR, and SPUR values in more diverse microbial communities. DO: dissolved oxygen; Eco-HEMS: eco-friendly high efficiency marine sludge; F/M: food and microorganism ratio; HRT: hydraulic retention time; ML(V)SS: mixed liquor (volatile) suspended solids; NCBI: National Center for Biotechnology Information; ND: not determined; qPCR: quantitative real-time polymerase chain

  5. Defining seascapes for marine unconsolidated shelf sediments in an eastern boundary upwelling region: The southern Benguela as a case study

    Science.gov (United States)

    Karenyi, Natasha; Sink, Kerry; Nel, Ronel

    2016-02-01

    Marine unconsolidated sediment habitats, the largest benthic ecosystem, are considered physically controlled ecosystems driven by a number of local physical processes. Depth and sediment type are recognised key drivers of these ecosystems. Seascape (i.e., marine landscape) habitat classifications are based solely on consistent geophysical features and provide an opportunity to define unconsolidated sediment habitats based on processes which may vary in distribution through space and time. This paper aimed to classify unconsolidated sediment seascapes and explore their diversity in an eastern boundary upwelling region at the macro-scale, using the South African west coast as a case study. Physical variables such as sediment grain size, depth and upwelling-related variables (i.e., maximum chlorophyll concentration, austral summer bottom oxygen concentration and sediment organic carbon content) were included in the analyses. These variables were directly measured through sampling, or collated from existing databases and the literature. These data were analysed using multivariate Cluster, Principal Components Ordination and SIMPER analyses (in PRIMER 6 + with PERMANOVA add-in package). There were four main findings; (i) eight seascapes were identified for the South African west coast based on depth, slope, sediment grain size and upwelling-related variables, (ii) three depth zones were distinguished (inner, middle and outer shelf), (iii) seascape diversity in the inner and middle shelves was greater than the outer shelf, and (iv) upwelling-related variables were responsible for the habitat diversity in both inner and middle shelves. This research demonstrates that the inclusion of productivity and its related variables, such as hypoxia and sedimentary organic carbon, in seascape classifications will enhance the ability to distinguish seascapes on continental shelves, where productivity is most variable.

  6. A synthesis of marine sediment core δ13C data over the last 150 000 years

    Directory of Open Access Journals (Sweden)

    R. E. M. Rickaby

    2010-10-01

    Full Text Available The isotopic composition of carbon, δ13C, in seawater is used in reconstructions of ocean circulation, marine productivity, air-sea gas exchange, and biosphere carbon storage. Here, a synthesis of δ13C measurements taken from foraminifera in marine sediment cores over the last 150 000 years is presented. The dataset comprises previously published and unpublished data from benthic and planktonic records throughout the global ocean. Data are placed on a common δ18O age scale suitable for examining orbital timescale variability but not millennial events, which are removed by a 10 ka filter. Error estimates account for the resolution and scatter of the original data, and uncertainty in the relationship between δ13C of calcite and of dissolved inorganic carbon (DIC in seawater. This will assist comparison with δ13C of DIC output from models, which can be further improved using model outputs such as temperature, DIC concentration, and alkalinity to improve estimates of fractionation during calcite formation. High global deep ocean δ13C, indicating isotopically heavy carbon, is obtained during Marine Isotope Stages (MIS 1, 3, 5a, c and e, and low δ13C during MIS 2, 4 and 6, which are temperature minima, with larger amplitude variability in the Atlantic Ocean than the Pacific Ocean. This is likely to result from changes in biosphere carbon storage, modulated by changes in ocean circulation, productivity, and air-sea gas exchange. The North Atlantic vertical δ13C gradient is greater during temperature minima than temperature maxima, attributed to changes in the spatial extent of Atlantic source waters. There are insufficient data from shallower than 2500 m to obtain a coherent pattern in other ocean basins. The data synthesis indicates that basin-scale δ13C during the last interglacial (MIS 5e is not clearly distinguishable from the Holocene (MIS 1 or from MIS 5a and 5c, despite significant differences in ice volume and atmospheric CO2

  7. Northern Gulf Littoral Initiative (NGLI), Geology and Physical Properties of Marine Sediments in the N.E. Gulf of Mexico: Data Report

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Northern Gulf Littoral Initiative (NGLI), Geology and Physical Properties of Marine Sediments in the N.E. gulf of Mexico: Data Report, was produced by the U.S....

  8. Composite cement mortars based on marine sediments and oyster shell powder

    Directory of Open Access Journals (Sweden)

    Ez-zaki, H.

    2016-03-01

    Full Text Available Additions of dredged marine sediments and oyster shell powder (OS as cement substitute materials in mortars are examined by several techniques. The sediments have high water and chloride contents and calcite, quartz, illite and kaolinite as principal minerals. The OS powders are entirely composed of calcium carbonate and traces of other impurities. Four mixtures of treated sediments and OS powders at 650 °C and 850 °C are added to Portland cement at 8%, 16% and 33% by weight. The hydration of composite pastes is followed by calorimetric tests, the porosity accessible to water, the bulk density, the permeability to gas, the compressive strength and the accelerated carbonation resistance are measured. In general, the increase of addition amounts reduced the performance of mortars. However, a reduction of gas permeability was observed when the addition was up to 33%. Around 16% of addition, the compressive strength and carbonation resistance were improved.En este trabajo se ha valorado la sustitución de cemento en morteros por sedimentos marinos dragados y polvo de concha de ostra (OS. Los sedimentos tienen altos contenidos de agua, cloruros, calcita, cuarzo, illita y caolinita como minerales principales. Los polvos OS están compuestos de carbonato cálcico y trazas de otras impurezas. Se añadieron a un cemento Portland, cuatro mezclas de los sedimentos y polvos de OS tratados a 650 °C y 850 °C en proporciones del 8%, 16% y 33% en peso. La hidratación de pastas se estudió a través de calorimetría. Se estudió además la porosidad accesible al agua, densidad aparente, permeabilidad al gas, resistencia a compresión y carbonatación acelerada. En general, un aumento en la adición produjo una reducción del rendimiento de los morteros. Se observó, sin embargo, una reducción de la permeabilidad a los gases con porcentajes de adición de hasta el 33%. Con valores del 16% de sustitución, mejoraron las resistencias mecánicas y la

  9. Simultaneous enumeration of diatom, protozoa and meiobenthos from marine sediments using Ludox-QPS method

    Institute of Scientific and Technical Information of China (English)

    DU Yongfen; XU Kuidong; LEI Yanli

    2009-01-01

    The Ludox-QPS method is a newly developed technique, which combines the Ludox HS 40 density centrifugation and quantitative protargol stain, to enumerate marine ciliates with good taxonomic resolution. We tested the method for simultaneous enumeration of diatoms, protozoa and meiobenthos and compared its extraction efficiency for meiobenthos with that of the routine Ludox-TM centrifugation and a modified protocol using Ludox HS 40. We conducted the evaluation with a sample size of 8.3 ml each from sandy, muddy-sand and muddy sediments collected from the intertidal area of the Yellow Sea in summer 2006 and spring 2007. The Ludox-QPS method not only produced high extraction efficiencies of 97±1.3% for diatoms and 97.6±0.8% for ciliates, indicating a reliable enumeration for eukaryotic microbenthos, but also produced excellent extraction efficiencies of on average 97.3% for total meiobenthos, 97.9% for nematodes and 97.8% for copepods from sands, muddy sands and mud. By contrast, the routine Ludox-TM centrifugation obtained only about 74% of total meiobenthos abundance with one extraction cycle, and the modified Ludox HS 40 centrifugation yielded on average 93% of total meiobenthos: 89.4±2.0% from sands, 93±4.1% from muddy sands and 97.1±3.0% from mud. Apart from the sediment type, sample volume was another important factor affecting the extraction efficiency for meiobenthos. The extraction rate was increased to about 96.4% when using the same modified Ludox centrifugation for a 4 ml sediment sample. Besides the excellent extraction efficiency, the Ludox-QPS method obtained higher abundances of meiobenthos, in particular nematodes, than the routine Ludox centrifugation, which frequently resulted in an uncertain loss of small meiobenthos during the sieving process. Statistical analyses demonstrated that there were no significant differences between the meiobenthos communities revealed by the Ludox-QPS method and the modified Ludox HS 40 centrifugation, showing the

  10. Alkenone paleothermometry: Biological lessons from marine sediment records off western South America

    Science.gov (United States)

    Prahl, Fredrick G.; Mix, Alan C.; Sparrow, Margaret A.

    2006-01-01

    An empirical global core-top calibration that relates the alkenone unsaturation index U37K' to mean annual SST (maSST) is statistically the same as that defined for a subarctic Pacific strain of Emiliania huxleyi (CCMP1742) grown exponentially in batch culture under isothermal conditions. Although both equations have been applied widely for paleoSST reconstruction, uncertainty still stems from two key ecological factors: variability in the details of biosynthesis among genetically distinct alkenone-producing strains, and impacts of non-thermal physiological growth factors on U37K'. New batch culture experiments with CCMP1742 here reveal that U37K' diverge systematically from the core-top calibration in response to nutrient depletion and light deprivation, two physiological stresses experienced by phytoplankton populations in the real ocean. Other aspects of alkenone/alkenoate composition also respond to these stresses and may serve as signatures of such effects, providing an opportunity to detect, understand, and potentially correct for such impacts on the geologic record. A test case documents that sediments from the Southeast Pacific display the alkenone/alkenoate compositional signature characteristic of cells physiologically stressed by light deprivation. Such an observation could be explained if marine snow provided a major vector of sedimentation for these biomarkers. Late Pleistocene U37K' records in the Southeast Pacific yield plausible paleotemperature histories of ice-age cooling, but ice-age alkenone/alkenoate signatures fall outside the range of modern calibration samples of similar U37K'. They better match core-top samples deposited beneath waters characterized by much cooler maSST, suggesting key features of ice-age ecology for alkenone-producing haptophytes were different from today, and that the U37K' index taken alone may misgauge the total range of ice-age cooling at these locations. Analysis of the full spectrum of alkenone/alkenoate compositions

  11. Use of neutralized industrial residue to stabilize trace elements (Cu, Cd, Zn, As, Mo, and Cr) in marine dredged sediment from South-East of France.

    Science.gov (United States)

    Taneez, Mehwish; Marmier, Nicolas; Hurel, Charlotte

    2016-05-01

    Management of marine dredged sediments polluted with trace elements is prime issue in the French Mediterranean coast. The polluted sediments possess ecological threats to surrounding environment on land disposal. Therefore, stabilization of contaminants in multi-contaminated marine dredged sediment is a promising technique. Present study aimed to assess the effect of gypsum neutralized bauxaline(®) (bauxite residue) to decrease the availability of pollutants and inherent toxicity of marine dredged sediment. Bauxaline(®), (alumia industry waste) contains high content of iron oxide but its high alkalinity makes it not suitable for the stabilization of all trace elements from multi-contaminated dredged sediments. In this study, neutralized bauxaline(®) was prepared by mixing bauxaline(®) with 5% of plaster. Experiments were carried out for 3 months to study the effect of 5% and 20% amendment rate on the availability of Cu, Cd, Zn, As, Mo, and Cr. Trace elements concentration, pH, EC and dissolved organic carbon were measured in all leachates. Toxicity of leachates was assessed against marine rotifers Brachionus plicatilis. The Results showed that both treatments have immobilization capacity against different pollutants. Significant stabilization of contaminants (Cu, Cd, Zn) was achieved with 20% application rate whereas As, Mo, and Cr were slightly stabilized. Toxicity results revealed that leachates collected from treated sediment were less toxic than the control sediment. These results suggest that application of neutralized bauxaline(®) to dredged sediment is an effective approach to manage large quantities of dredged sediments as well as bauxite residue itself.

  12. Lethal effects on different marine organisms, associated with sediment-seawater acidification deriving from CO2 leakage.

    Science.gov (United States)

    Basallote, M D; Rodríguez-Romero, A; Blasco, J; DelValls, A; Riba, I

    2011-08-01

    CO(2) leakages during carbon capture and storage in sub-seabed geological structures could produce potential impacts on the marine environment. To study lethal effects on marine organisms attributable to CO(2) seawater acidification, a bubbling CO(2) system was designed enabling a battery of different tests to be conducted, under laboratory conditions, employing various pH treatments (8.0, 7.5, 7.0, 6.5, 6.0, and 5.5). Assays were performed of three exposure routes (seawater, whole sediment, and sediment elutriate). Individuals of the clam (Ruditapes philippinarum) and early-life stages of the gilthead seabream, Sparus aurata, were exposed for 10 days and 72 h, respectively, to acidified clean seawater. S. aurata larvae were also exposed to acidified elutriate samples, and polychaete organisms of the specie Hediste diversicolor and clams R. philippinarum were also exposed for 10 days to estuarine whole sediment. In the fish larvae elutriate test, 100 % mortality was recorded at pH 6.0, after 48 h of exposure. Similar results were obtained in the clam sediment exposure test. In the other organisms, significant mortality (p < 0.05) was observed at pH values lower than 6.0. Very high lethal effects (calculating L[H(+)]50, defined as the H(+) concentration that causes lethal effects in 50 % of the population exposed) were detected in association with the lowest pH treatment for all the species. The implication of these results is that a severe decrease of seawater pH would cause high mortality in marine organisms of several different kinds and life stages. The study addresses the potential risks incurred due to CO(2) leakages in marine environments.

  13. Application of microwave energy to speed up the alkaline extraction of humic and fulvic acids from marine sediments.

    Science.gov (United States)

    Romarís-Hortas, Vanessa; Moreda-Piñeiro, Antonio; Bermejo-Barrera, Pilar

    2007-10-29

    The feasibility of microwave energy to speed up the alkaline extraction of humic substances (humic acid, HA, and fulvic acid, FA) from marine sediments has been checked. Extractions were performed by using 20 mL of sodium hydroxide at 0.1 M (two repeated extractions) after an ultrasound-assisted acid pre-treatment of samples to remove the carbonate fraction (ultrasound power at 17 kHz, 10 mL of 6.0 M hydrochloric acid for 15 min). After separation of HA and FA fractions by acidifying with 6 M HCl, the FA fraction (supernatant) was purified by passing the solution through a column of Amberlite XAD-8. Both HA and FA extracts were measured by UV-visible spectrophotometry. All variables affecting the extraction process (sodium hydroxide concentration and volume, ramp and hold times, temperature and number of repeated extractions) have been screened by using a Plackett-Burman design (PBD) as multivariate approach. The variables temperature and number of repeated extractions were the most significant factors (P=95%) affecting the extraction of both FA and HA from marine sediments. These two variables have led optimum values of 150 degrees C and two repeated extractions. The developed method has been found precise (R.S.D.s of 9% for HA and 12% for FA, for 11 determinations) and its results were comparable in terms of elemental (C, H and N) composition to those obtained after applying methods based on mechanical stirring and ultrasounds assisting. However, higher HA and FA concentrations than those obtained after conventional stirring and ultrasound irradiation were obtained when applying microwave energy. This means a higher efficiency of microwave energy than ultrasounds or mechanical stirring to extract HA and FA fractions from marine sediments. The method was finally applied to different surface marine sediments from the Ría de Arousa estuary.

  14. The Role of the Horizontal Gene Pool and Lateral Gene Transfer in Enhancing Microbial Activities in Marine Sediments

    Science.gov (United States)

    2006-05-10

    suitable for the construction of ’plasmid metagenome libraries’. Such libraries would provide access to the unculturable fraction of plasmids resident in...marine water and sediment systems will allow one to examine not only the prevalence of microorganisms but to identify extrachromosomal elements that are...suitable for the construction of ’plasmid metagenome libraries’. Such libraries would provide access to the unculturable fraction of plasmids resident

  15. Thiosulfate and Sulfite Distributions in Porewater of Marine-Sediments Related to Manganese, Iron, and Sulfur Geochemistry

    DEFF Research Database (Denmark)

    Thamdrup, B; Finster, Kai; Fossing, Henrik;

    1994-01-01

    Depth distributions of thiosulfate (S2O32-) and sulfite (SO32-) were measured in the porewaters of a Danish salt marsh and subtidal marine sediments by HPLC analysis after derivatization with DTNP [2,2'-dithiobis(5-nitropyridine)]. The distributions were compared to the redox zonation as indicate...... by Eh and Mn2+, Fe2+, and H2S distributions. Concentrations Of S2O32- varied from below detection (...

  16. Cultivation of autotrophic ammonia-oxidizing archaea from marine sediments in coculture with sulfur-oxidizing bacteria.

    Science.gov (United States)

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

    2010-11-01

    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 enrichment of AOA over ammonia-oxidizing bacteria (AOB) is likely due to the reduced oxygen levels caused by the rapid initial growth of SOB. After biweekly transfers for ca. 20 months, archaeal cells became the dominant prokaryotes (>80%), based on quantitative PCR and fluorescence in situ hybridization analysis. The increase of archaeal 16S rRNA gene copy numbers was coincident with the amount of ammonia oxidized, and expression of the archaeal amoA gene was observed during ammonia oxidation. Bacterial amoA genes were not detected in the enrichment culture. The affinities of these AOA to oxygen and ammonia were substantially higher than those of AOB. [(13)C]bicarbonate incorporation and the presence and activation of genes of the 3-hydroxypropionate/4-hydroxybutyrate cycle indicated autotrophy during ammonia oxidation. In the enrichment culture, ammonium was oxidized to nitrite by the AOA and subsequently to nitrate by Nitrospina-like bacteria. Our experiments suggest that AOA may be important nitrifiers in low-oxygen environments, such as oxygen-minimum zones and marine sediments.

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

    Science.gov (United States)

    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 enrichment of AOA over ammonia-oxidizing bacteria (AOB) is likely due to the reduced oxygen levels caused by the rapid initial growth of SOB. After biweekly transfers for ca. 20 months, archaeal cells became the dominant prokaryotes (>80%), based on quantitative PCR and fluorescence in situ hybridization analysis. The increase of archaeal 16S rRNA gene copy numbers was coincident with the amount of ammonia oxidized, and expression of the archaeal amoA gene was observed during ammonia oxidation. Bacterial amoA genes were not detected in the enrichment culture. The affinities of these AOA to oxygen and ammonia were substantially higher than those of AOB. [13C]bicarbonate incorporation and the presence and activation of genes of the 3-hydroxypropionate/4-hydroxybutyrate cycle indicated autotrophy during ammonia oxidation. In the enrichment culture, ammonium was oxidized to nitrite by the AOA and subsequently to nitrate by Nitrospina-like bacteria. Our experiments suggest that AOA may be important nitrifiers in low-oxygen environments, such as oxygen-minimum zones and marine sediments. PMID:20870784

  18. Carbohydrates, uronic acids and alkali extractable carbohydrates in contrasting marine and estuarine sediments: Distribution, size fractionation and partial chemical characterization

    Digital Repository Service at National Institute of Oceanography (India)

    Khodse, V.B.; Fernandes, L.; Bhosle, N.B.; Sardessai, S.

    result in depth invariant profiles and low yields of particulate carbohydrates, indicating the inert nature of some of the sedimentary carbohydrates (Hamilton and Hedges, 1988; Jensen et al., 2005). Monosaccharide composition of neutral carbohydrates... and sugar ratios in a sample has been used to distinguish terrestrial, marine and siliceous and carbonaceous inputs to the suspended particulate matter and sediments (Cowie and Hedges, 1984; Ittekkot et. al., 1984). Moreover, contribution of neutral...

  19. Release of Ni from birnessite during transformation of birnessite to todorokite: Implications for Ni cycling in marine sediments

    Science.gov (United States)

    Atkins, Amy L.; Shaw, Samuel; Peacock, Caroline L.

    2016-09-01

    The phyllomanganate birnessite is the main Mn-bearing phase in oxic marine sediments where it exerts a primary control on the concentration of micronutrient trace metals in seawater. However, during sediment diagenesis and under mild hydrothermal conditions birnessite transforms into the tectomanganate todorokite. We have recently shown that the transformation of birnessite to todorokite proceeds via a four-stage nucleation and growth mechanism, beginning with todorokite nucleation, then crystal growth from solution to form todorokite primary particles, followed by their self-assembly and oriented growth via oriented attachment to form crystalline todorokite laths, culminating in traditional crystal ripening (Atkins et al., 2014). Here we determine the fate and mobility of Ni sorbed by birnessite during this transformation process. Specifically, in our recent work we predict that the presence of Ni within the phyllomanganate matrix will disrupt the formation of todorokite primary particles. As such, contrary to current understanding, we suggest that Ni sorbed by birnessite will slow the transformation of birnessite to todorokite and/or be released to marine porewaters during sediment diagenesis. Here we transform a synthetic, poorly crystalline, Ni-sorbed (∼1 wt% Ni) hexagonal birnessite, analogous to marine birnessite, into todorokite under a mild reflux procedure, developed to mimic marine diagenesis and mild hydrothermal conditions. We characterise our birnessite and reflux products as a time series, including X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM) and extended X-ray absorption fine structure (EXAFS) spectroscopy. In addition we determine Ni speciation and mineral phase associations in a suite of natural marine ferromanganese precipitates, containing intermixed phyllomanganate and todorokite. Our work shows for the first time that Ni significantly slows the transformation of birnessite to todorokite and reduces the

  20. An improved method for quantitatively measuring the sequences of total organic carbon and black carbon in marine sediment cores

    Science.gov (United States)

    Xu, Xiaoming; Zhu, Qing; Zhou, Qianzhi; Liu, Jinzhong; Yuan, Jianping; Wang, Jianghai

    2017-04-01

    Understanding global carbon cycle is critical to uncover the mechanisms of global warming and remediate its adverse effects on human activities. Organic carbon in marine sediments is an indispensable part of the global carbon reservoir in global carbon cycling. Evaluating such a reservoir calls for quantitative studies of marine carbon burial, which closely depend on quantifying total organic carbon and black carbon in marine sediment cores and subsequently on obtaining their high-resolution temporal sequences. However, the conventional methods for detecting the contents of total organic carbon or black carbon cannot resolve the following specific difficulties, i.e., (1) a very limited amount of each subsample versus the diverse analytical items, (2) a low and fluctuating recovery rate of total organic carbon or black carbon versus the reproducibility of carbon data, and (3) a large number of subsamples versus the rapid batch measurements. In this work, (i) adopting the customized disposable ceramic crucibles with the micropore-controlled ability, (ii) developing self-made or customized facilities for the procedures of acidification and chemothermal oxidization, and (iii) optimizing procedures and carbon-sulfur analyzer, we have built a novel Wang-Xu-Yuan method (the WXY method) for measuring the contents of total organic carbon or black carbon in marine sediment cores, which includes the procedures of pretreatment, weighing, acidification, chemothermal oxidation and quantification; and can fully meet the requirements of establishing their highresolution temporal sequences, whatever in the recovery, experimental efficiency, accuracy and reliability of the measurements, and homogeneity of samples. In particular, the usage of disposable ceramic crucibles leads to evidently simplify the experimental scenario, which further results in the very high recovery rates for total organic carbon and black carbon. This new technique may provide a significant support for

  1. Exopolysaccharide production by a marine Pseudoalteromonas sp. strain isolated from Madeira Archipelago ocean sediments.

    Science.gov (United States)

    Roca, Christophe; Lehmann, Mareen; Torres, Cristiana A V; Baptista, Sílvia; Gaudêncio, Susana P; Freitas, Filomena; Reis, Maria A M

    2016-06-25

    Exopolysaccharides (EPS) are polymers excreted by some microorganisms with interesting properties and used in many industrial applications. A new Pseudoalteromonas sp. strain, MD12-642, was isolated from marine sediments and cultivated in bioreactor in saline culture medium containing glucose as carbon source. Its ability to produce EPS under saline conditions was demonstrated reaching an EPS production of 4.4g/L within 17hours of cultivation, corresponding to a volumetric productivity of 0.25g/Lh, the highest value so far obtained for Pseudoalteromonas sp. strains. The compositional analysis of the EPS revealed the presence of galacturonic acid (41-42mol%), glucuronic acid (25-26mol%), rhamnose (16-22mol%) and glucosamine (12-16mol%) sugar residues. The polymer presents a high molecular weight (above 1000kDa). These results encourage the biotechnological exploitation of strain MD12-642 for the production of valuable EPS with unique composition, using saline by-products/wastes as feedstocks. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. History effects in the sedimentation of light aerosols in turbulence: The case of marine snow

    Science.gov (United States)

    Guseva, Ksenia; Daitche, Anton; Feudel, Ulrike; Tél, Tamás

    2016-11-01

    We analyze the effect of the Basset history force on the sedimentation of nearly neutrally buoyant particles, exemplified by marine snow, in a three-dimensional turbulent flow. Particles are characterized by Stokes numbers much smaller than unity, and still water settling velocities, measured in units of the Kolmogorov velocity, of order one. The presence of the history force in the Maxey-Riley equation leads to individual trajectories which differ strongly from the dynamics of both inertial particles without this force and ideal settling tracers. The main effect of the history force is an extraordinary slow, power-law type convergence to an asymptotic settling velocity of the center of mass, which is found numerically to be the settling velocity in still fluid. The spatial extension of the ensemble grows diffusively after an initial ballistic growth lasting up to circa one large eddy turnover time. We demonstrate that the settling of the center of mass for such light aggregates is best approximated by the settling dynamics in still fluid found with the history force, on top of which fluctuations appear which follow very closely those of the turbulent velocity field.

  3. Diversity and Bioactivity of Actinomycetes from Marine Sediments of the Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shumin; YE Liang; TANG Xuexi

    2012-01-01

    Among the 116 actinomycetes collected from marine sediments of the Yellow Sea,56 grew slowly and appeared after 2-3 weeks of incubation.Among the 56 strains,only 3 required seawater (SW) for growth,and 21 grew well in the medium prepared with SW rather than distilled water (DW),while the remaining 32 grew well either with SW or with DW.Six representatives with different morphological characteristics,including 1 SW-requiring strain and 5 well-growing with SW strains,were selected for phylogenetic analysis based on 16S rRNA gene.Two strains belong to Micrococcaceae and Nocardiopsaceae respectively.The other 4strains belong to the family of Streptomycetaceae.In the analyzed 6 strains,one was related to Nocardiopsis spp.and the other three were related to Streptomyces spp.,representing new taxa.Bioactivity testing of fermentation products from 3 SW-requiring strains and 21 well-growing with SW strains revealed that 17 strains possessed remarkable activities against gram-positive pathogen or/and tumor cells,suggesting that they were prolific resources for natural drug discovery.

  4. Polyethylene Glycol Drilling Fluid for Drilling in Marine Gas Hydrates-Bearing Sediments: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Lixin Kuang

    2011-01-01

    Full Text Available Shale inhibition, low-temperature performance, the ability to prevent calcium and magnesium-ion pollution, and hydrate inhibition of polyethylene glycol drilling fluid were each tested with conventional drilling-fluid test equipment and an experimental gas-hydrate integrated simulation system developed by our laboratory. The results of these tests show that drilling fluid with a formulation of artificial seawater, 3% bentonite, 0.3% Na2CO3, 10% polyethylene glycol, 20% NaCl, 4% SMP-2, 1% LV-PAC, 0.5% NaOH and 1% PVP K-90 performs well in shale swelling and gas hydrate inhibition. It also shows satisfactory rheological properties and lubrication at temperature ranges from −8 °C to 15 °C. The PVP K-90, a kinetic hydrate inhibitor, can effectively inhibit gas hydrate aggregations at a dose of 1 wt%. This finding demonstrates that a drilling fluid with a high addition of NaCl and a low addition of PVP K-90 is suitable for drilling in natural marine gas-hydrate-bearing sediments.

  5. Quick, portable toxicity testing of marine or terrigenous fluids, sediments, or chemicals with bioluminescent organism

    Energy Technology Data Exchange (ETDEWEB)

    Sabate, R.W.; Stiffey, A.V.; Dewailly, E.L. [Lumitox Gulf L.C., New Orleans, LA (United States)

    1995-12-31

    A hand-held, battery-operated instrument, which measures bioluminescence inhibition of the microscopic marine dinoflagellate Pyrocystis lunula, is capable of field-testing substances for toxicity. The organism is sensitive to ppb of strong toxicants. It tolerates some solvents in concentrations necessary for testing lipophylic samples. A test consumes only micrograms of sample. This method requires no adjustments for salinity, pH, color, or turbidity. It has been used successfully to test oil-well drilling fluids, brines produced with oil, waters and sediments from streams and lakes and petroleum-plant effluents containing contaminants such as benzene. The test is non-specific; however, if the substance is known, the end-point effects a direct measurement of its concentration. One-hour toxicity screening tests in the field produce results comparable to the standard four-hour laboratory test. Keeping the sample in the dark during incubation and testing, together with shortness of the overall procedure, eliminates anomalies from light-sensitive substances. Day-to-day variation, as well as among test replicates, is less than 10%. This quick method yields results comparable with a quick test that uses Photobacterium phosphoria, and with 96-hour tests that use Mysidopsis bahia, Artemia salina, Gonyaulax polyedra, Pimephales promelas, Ceriodaphnia dubia, and Cyprinodon variegatus.

  6. Offshore drilling effects in Brazilian SE marine sediments: a meta-analytical approach.

    Science.gov (United States)

    Dore, Marina Pereira; Farias, Cássia; Hamacher, Cláudia

    2017-01-01

    The exploration and production of oil and gas reserves often result to drill cutting accumulations on the seafloor adjacent to drill locations. In this study, the detection of drilling influence on marine sediments was performed by meta-analytical comparison between data from pre- and post-drilling surveys undertaken in offshore Campos Basin, southeast of Brazil. Besides this overall appraisal on the geochemical variables, a multivariate assessment, considering only the post-drilling data, was performed. Among the variables, fines content, carbonates, total organic carbon, barium, chromium, copper, iron, manganese, nickel, lead, vanadium, zinc, and total petroleum hydrocarbons, only barium, copper, and hydrocarbons were related to drilling impacts. In relation to the point of discharge, relative elevated levels in the post-drilling campaigns were observed preferentially up to 500 m in the northeast and southwest directions, associated to the Brazil Current-predominant direction. Other distributed concentrations in the surroundings seem to indicate the dilution and dispersion of drilling waste promoted by meteoceanographic factors.

  7. Biodegradation of PAHs by Burkholderia sp. VITRSB1 Isolated from Marine Sediments

    Directory of Open Access Journals (Sweden)

    T. Revathy

    2015-01-01

    Full Text Available The polycyclic aromatic hydrocarbons (PAHs pollution to the environment is a major threat to the living organisms, and hence the degradation of these PAHs is necessary. Studies on PAHs degrading bacteria have focussed on terrestrial microbes and the potential of marine derived microbes is undermined. Herein we report the isolation and characterization of PAHs degrading Burkholderia sp. from lagoon sediments collected at the Southern coast of India. The strain was Gram negative, rod-shaped, motile, and ∼2–5 μm in length. Based on the phylogenetic data the strain was identified as Burkholderia and designated as VITRSB1. Initial PAHs degradation ability of the strain was assessed using basal salt medium supplemented with diesel, kerosene, toluene, aniline, naphthalene, and phenol. The strain was found to be effectively degrading kerosene, diesel, toluene, and aniline even at higher concentration (1%. However, naphthalene and aniline were degraded only at lower concentration (0.1% and phenol, camphor, and DAP inhibited the growth of the strain. Furthermore, the degraded end products of the PAHs were determined using FTIR. Notably, none of the end products were found to be toxic to the biosphere. Our results indicate that the isolated Burkholderia sp. could be a prospective candidate for the effective degradation of selective PAHs.

  8. Investigation of saponification for determination of polychlorinated biphenyls in marine sediments.

    Science.gov (United States)

    Numata, Masahiko; Yarita, Takashi; Aoyagi, Yoshie; Yamazaki, Misako; Takatsu, Akiko

    2005-02-01

    The effects of saponification conditions (temperature and water content of saponifying solution) on the determination of chlorinated biphenyls (CBs) in marine sediments were investigated. Although highly chlorinated biphenyls (nona- to deca-CBs) decomposed during high-temperature saponification, the degree of degradation was reduced by adding water to the ethanolic potassium hydroxide saponifying solution. Room-temperature saponification yielded quantitative recovery of highly chlorinated biphenyl surrogates but low extraction efficiencies of lightly chlorinated biphenyls (mono- to di-CBs). The same samples were analyzed by other extraction techniques, for example, pressurized liquid extraction, and analytical results were compared. The mono- and di-CB concentrations were correlated with the extraction temperatures of various extraction techniques. In particular, the concentrations of some CB congeners (CB11, CB14) were higher with saponification. The low degree of degradation of highly chlorinated biphenyls and the high recovery of lightly chlorinated biphenyls were compatible when room-temperature and high-temperature saponification were combined. Except for the anomalies of CB11 and CB14, the combined method gave satisfactory results for analysis of PCBs.

  9. Diversity and bioactivity of actinomycetes from marine sediments of the Yellow Sea

    Science.gov (United States)

    Zhang, Shumin; Ye, Liang; Tang, Xuexi

    2012-03-01

    Among the 116 actinomycetes collected from marine sediments of the Yellow Sea, 56 grew slowly and appeared after 2-3 weeks of incubation. Among the 56 strains, only 3 required seawater (SW) for growth, and 21 grew well in the medium prepared with SW rather than distilled water (DW), while the remaining 32 grew well either with SW or with DW. Six representatives with different morphological characteristics, including 1 SW-requiring strain and 5 well-growing with SW strains, were selected for phylogenetic analysis based on 16S rRNA gene. Two strains belong to Micrococcaceae and Nocardiopsaceae respectively. The other 4 strains belong to the family of Streptomycetaceae. In the analyzed 6 strains, one was related to Nocardiopsis spp. and the other three were related to Streptomyces spp., representing new taxa. Bioactivity testing of fermentation products from 3 SW-requiring strains and 21 well-growing with SW strains revealed that 17 strains possessed remarkable activities against gram-positive pathogen or/and tumor cells, suggesting that they were prolific resources for natural drug discovery.

  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. Archival policies and collections database for the Woods Hole Science Center's marine sediment samples

    Science.gov (United States)

    Buczkowski, Brian J.; Kelsey, Sarah A.

    2007-01-01

    The Woods Hole Science Center of the U.S. Geological Survey (USGS) has been an active member of the Woods Hole research community, Woods Hole, Massachusetts, for over 40 years. In that time there have been many projects that involved the collection of sediment samples conducted by USGS scientists and technicians for the research and study of seabed environments and processes. These samples were collected at sea or near shore and then brought back to the Woods Hole Science Center (WHSC) for analysis. While at the center, samples are stored in ambient temperature, refrigerated and freezing conditions ranging from +2º Celsius to -18º Celsius, depending on the best mode of preparation for the study being conducted or the duration of storage planned for the samples. Recently, storage methods and available storage space have become a major concern at the WHSC. The core and sediment archive program described herein has been initiated to set standards for the management, methods, and duration of sample storage. A need has arisen to maintain organizational consistency and define storage protocol. This handbook serves as a reference and guide to all parties interested in using and accessing the WHSC's sample archive and also defines all the steps necessary to construct and maintain an organized collection of geological samples. It answers many questions as to the way in which the archive functions.

  12. Microbial distributions detected by an oligonucleotide microarray across geochemical zones associated with methane in marine sediments from the Ulleung Basin

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, Brandon R; Graw, Michael; Brodie, Eoin L; Bahk, Jang-Jun; Kim, Sung-Han; Hyun, Jung-Ho; Kim, Ji-Hoon; Torres, Marta; Colwell, Frederick S

    2013-11-01

    The biogeochemical processes that occur in marine sediments on continental margins are complex; however, from one perspective they can be considered with respect to three geochemical zones based on the presence and form of methane: sulfate–methane transition (SMTZ), gas hydrate stability zone (GHSZ), and free gas zone (FGZ). These geochemical zones may harbor distinct microbial communities that are important in biogeochemical carbon cycles. The objective of this study was to describe the microbial communities in sediments from the SMTZ, GHSZ, and FGZ using molecular ecology methods (i.e. PhyloChip microarray analysis and terminal restriction fragment length polymorphism (T-RFLP)) and examining the results in the context of non-biological parameters in the sediments. Non-metric multidimensional scaling and multi-response permutation procedures were used to determine whether microbial community compositions were significantly different in the three geochemical zones and to correlate samples with abiotic characteristics of the sediments. This analysis indicated that microbial communities from all three zones were distinct from one another and that variables such as sulfate concentration, hydrate saturation of the nearest gas hydrate layer, and depth (or unmeasured variables associated with depth e.g. temperature, pressure) were correlated to differences between the three zones. The archaeal anaerobic methanotrophs typically attributed to performing anaerobic oxidation of methane were not detected in the SMTZ; however, the marine benthic group-B, which is often found in SMTZ, was detected. Within the GHSZ, samples that were typically closer to layers that contained higher hydrate saturation had indicator sequences related to Vibrio-type taxa. These results suggest that the biogeographic patterns of microbial communities in marine sediments are distinct based on geochemical zones defined by methane.

  13. Quantification, morphology and source of humic acid, kerogen and black carbon in offshore marine sediments from Xiamen Gulf, China

    Institute of Scientific and Technical Information of China (English)

    Yanting Chen; Jinping Zhao; Li qianYin; Jinsheng Chen; Dongxing Yuan

    2013-01-01

    Three types of macromolecular organic matters (MOMs),i.e.humic acid (HA),kerogen+black carbon (KB),and black carbon (BC)were extracted from marine sediments of Xiamen Gulf,southeast of China.The chemical composition,morphological property and source of the three extractions were characterized by elemental analyzer/isotope ratio mass spectrometry (EA/IRMS) and scanning electron microscope (SEM).The results showed that KB was the predominant fraction in MOMs,which accounted for 61.79%-89.15% of the total organic content (TOC),while HA consisted less than 5%.The relative high contents of kerogen and BC,and low contents of HA in the samples indicated that anthropogenic input might be the major source of organic matter in marine sediments near the industrial regions.The characterization of SEM,not only revealed morphological properties of the three fractions,but also allowed a better understanding of the source of MOMs.The δ13C values of the three fractions suggested that materials from terrestrial C3 plants were predominant.Furthermore,the anthropogenic activities,such as the discharge of sewage,coal and biomass combustion from industry nearby and agricultural practices within drainage basin of the Jiulong River,were remarkably contributed to the variations in δ13C values of MOMs in the offshore marine sediments.

  14. Effects of oil dispersants on settling of marine sediment particles and particle-facilitated distribution and transport of oil components.

    Science.gov (United States)

    Cai, Zhengqing; Fu, Jie; Liu, Wen; Fu, Kunming; O'Reilly, S E; Zhao, Dongye

    2017-01-15

    This work investigated effects of three model oil dispersants (Corexit EC9527A, Corexit EC9500A and SPC1000) on settling of fine sediment particles and particle-facilitated distribution and transport of oil components in sediment-seawater systems. All three dispersants enhanced settling of sediment particles. The nonionic surfactants (Tween 80 and Tween 85) play key roles in promoting particle aggregation. Yet, the effects varied with environmental factors (pH, salinity, DOM, and temperature). Strongest dispersant effect was observed at neutral or alkaline pH and in salinity range of 0-3.5wt%. The presence of water accommodated oil and dispersed oil accelerated settling of the particles. Total petroleum hydrocarbons in the sediment phase were increased from 6.9% to 90.1% in the presence of Corexit EC9527A, and from 11.4% to 86.7% for PAHs. The information is useful for understanding roles of oil dispersants in formation of oil-sediment aggregates and in sediment-facilitated transport of oil and PAHs in marine eco-systems.

  15. Evaluation of a bioassays battery for ecotoxicological screening of marine sediments from Ionian Sea (Mediterranea Sea, Southern Italy).

    Science.gov (United States)

    Prato, Ermelinda; Parlapiano, Isabella; Biandolino, Francesca

    2012-09-01

    Sediments are an ecologically important component of the aquatic environment and may play a key role in mediating the exchange of contaminants between particulate, dissolved, and biological phases. For a comprehensive assessment of potential sediment toxicity, the use of a single species may not detect toxicant with a specific mode of action. Therefore it is advisable to carry out ecotoxicological tests on a base-set of taxa utilizing test species belonging to different trophic levels. This paper describes the ecotoxicological evaluation of marine sediments from seven sites of Mar Piccolo estuary (Southern, Italy), four of them were located in the first inlet and three in the second inlet of Mar Piccolo estuary. Sediment samples from a site in Taranto Gulf were used as control sediment. Dunaliella tertiolecta, Tigriopus fulvus, Mytilus galloprovincialis, and Corophium insidiosum, were employed to identify the quality of sediments. The integration of biological tests results showed that all sampling sites located in the first inlet of Mar Piccolo were identified as toxic, according to all tests, while the sites of second inlet were found not toxic. The results obtained in this study indicate that the use of a battery of biological tests have important implications for risk assessment in estuarine e coastal waters.

  16. Exploring Actinobacteria assemblages in coastal marine sediments under contrasted Human influences in the West Istria Sea, Croatia.

    Science.gov (United States)

    Duran, Robert; Bielen, Ana; Paradžik, Tina; Gassie, Claire; Pustijanac, Emina; Cagnon, Christine; Hamer, Bojan; Vujaklija, Dušica

    2015-10-01

    The exploration of marine Actinobacteria has as major challenge to answer basic questions of microbial ecology that, in turn, will provide useful information to exploit Actinobacteria metabolisms in biotechnological processes. The ecological functions performed by Actinobacteria in marine sediments are still unclear and belongs to the most burning basic questions. The comparison of Actinobacteria communities inhabiting marine sediments that are under the influence of different contamination types will provide valuable information in the adaptation capacities of Actinobacteria to colonize specific ecological niche. In the present study, the characterization of different Actinobacteria assemblages according to contamination type revealed the ecological importance of Actinobacteria for maintaining both general biogeochemical functions through a "core" Actinobacteria community and specific roles associated with the presence of contaminants. Indeed, the results allowed to distinguish Actinobacteria genera and species operational taxonomic units (OTUs) able to cope with the presence of either (i) As, (ii) metals Ni, Fe, V, Cr, and Mn, or (iii) polycyclic aromatic hydrocarbons (PAHs) and toxic metals (Hg, Cd, Cu, Pb, and Zn). Such observations highlighted the metabolic capacities of Actinobacteria and their potential that should be taken into consideration and advantage during the implementation of bioremediation processes in marine ecosystems.

  17. Bioprospecting from Marine Sediments of New Brunswick, Canada: Exploring the Relationship between Total Bacterial Diversity and Actinobacteria Diversity

    Directory of Open Access Journals (Sweden)

    Katherine Duncan

    2014-02-01

    Full Text Available Actinomycetes are an important resource for the discovery of natural products with therapeutic properties. Bioprospecting for actinomycetes typically proceeds without a priori knowledge of the bacterial diversity present in sampled habitats. In this study, we endeavored to determine if overall bacterial diversity in marine sediments, as determined by 16S rDNA amplicon pyrosequencing, could be correlated with culturable actinomycete diversity, and thus serve as a powerful tool in guiding future bioprospecting efforts. Overall bacterial diversity was investigated in eight marine sediments from four sites in New Brunswick, Canada, resulting in over 44,000 high quality sequences (x̄ = 5610 per sample. Analysis revealed all sites exhibited significant diversity (H’ = 5.4 to 6.7. Furthermore, statistical analysis of species level bacterial communities (D = 0.03 indicated community composition varied according to site and was strongly influenced by sediment physiochemical composition. In contrast, cultured actinomycetes (n = 466, 98.3% Streptomyces were ubiquitously distributed among all sites and distribution was not influenced by sediment composition, suggesting that the biogeography of culturable actinomycetes does not correlate with overall bacterial diversity in the samples examined. These actinomycetes provide a resource for future secondary metabolite discovery, as exemplified by the antimicrobial activity observed from preliminary investigation.

  18. Bioprospecting from marine sediments of New Brunswick, Canada: exploring the relationship between total bacterial diversity and actinobacteria diversity.

    Science.gov (United States)

    Duncan, Katherine; Haltli, Bradley; Gill, Krista A; Kerr, Russell G

    2014-02-13

    Actinomycetes are an important resource for the discovery of natural products with therapeutic properties. Bioprospecting for actinomycetes typically proceeds without a priori knowledge of the bacterial diversity present in sampled habitats. In this study, we endeavored to determine if overall bacterial diversity in marine sediments, as determined by 16S rDNA amplicon pyrosequencing, could be correlated with culturable actinomycete diversity, and thus serve as a powerful tool in guiding future bioprospecting efforts. Overall bacterial diversity was investigated in eight marine sediments from four sites in New Brunswick, Canada, resulting in over 44,000 high quality sequences (x = 5610 per sample). Analysis revealed all sites exhibited significant diversity (H' = 5.4 to 6.7). Furthermore, statistical analysis of species level bacterial communities (D =