Microbial diversity and stratification of South Pacific abyssal marine sediments.

Science.gov (United States)

Durbin, Alan M; Teske, Andreas

2011-12-01

Abyssal marine sediments cover a large proportion of the ocean floor, but linkages between their microbial community structure and redox stratification have remained poorly constrained. This study compares the downcore gradients in microbial community composition to porewater oxygen and nitrate concentration profiles in an abyssal marine sediment column in the South Pacific Ocean. Archaeal 16S rRNA clone libraries showed a stratified archaeal community that changed from Marine Group I Archaea in the aerobic and nitrate-reducing upper sediment column towards deeply branching, uncultured crenarchaeotal and euryarchaeotal lineages in nitrate-depleted, anaerobic sediment horizons. Bacterial 16S rRNA clone libraries revealed a similar shift on the phylum and subphylum level within the bacteria, from a complex community of Alpha-, Gamma- and Deltaproteobacteria, Actinobacteria and Gemmatimonadetes in oxic surface sediments towards uncultured Chloroflexi and Planctomycetes in the anaerobic sediment column. The distinct stratification of largely uncultured bacterial and archaeal groups within the oxic and nitrate-reducing marine sediment column provides initial constraints for their microbial habitat preferences. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Stabilization / solidification of polluted marine dredged sediment of port en Bessin France, using hydraulic binders and silica fume

Science.gov (United States)

Silitonga, Ernesto

2017-09-01

A large amount of sediment is dredged in France every year. Due to the increase of the amount of marine dredged sediments, environmentally reuse of dredged sediment is urgently needed in France. The first objective of this study is to find an application for reuse of marine dredged sediments materials, as new material for road construction. Hence, serial tests need to be realized to identify if marine dredged sediment could be utilized for road construction. The second goal is to enhance the physical, mechanical and chemical characteristics of the mix, by incorporating binders and sediments, and revealed the identification of the mechanical characteristics measured on the mixes is compatible with their use as a base course material. The results show that the treatment by hydraulics binders could satisfy the needed mechanical characteristics. The present of Silica Fume is aimed to reduce the pollution level, especially the heavy metal content. However, the proportion of hydraulics binders and silica fume needed to meet prescribed specification is important, so the reuse of the marine dredged sediments of Port-en-Bessin, France in road construction, as an alternative material could be achieved. After the geotechnical study in laboratory results shown as expected than the study to identify the chemical characteristic realized. To evaluate the environmental impacts of the used material, leaching test is performed. The leaching test was performed to verify the predicted release of pollutants based on total dissolution. And for the final part, the test results show that the polluted marine dredged sediments could be safely used (in term of environmental impact) as a new material in road construction.

Convenient method of color measurement of marine sediments by colorimeter

Energy Technology Data Exchange (ETDEWEB)

Nagao, S [Japan Atomic Energy Research Inst., Ibaragi (Japan); Nakashima, S [Akita Univ., Akita (Japan). Research Inst. of Natural Resources

1991-01-01

Marine sediments exhibit various colors such as cream, gray, green, red, brown and black. Marine scientists conventionally judged colors of various types of marine sediments by visual observation which has several disadvantages. The purpose of the present study is to establish a color measurement method for various colors of dried marine sediments with the calorimeter and also to try a color measurement of wet core samples on board the ship. A colorimeter (Minolta Chroma Meter CR-200) was used to describe colors of wet and powdered sediment samples in L{sup *}a{sup *}b{sup *} values of the second CIE 1976 color space. Materials studied in this experiment for the color determination are from Japan sea(18 samples from 0-40.5 cm depth), East Pacific(21 samples from 0-42 cm depth) and Suruga Bay(23 samples from 0-110 cm depth), etc. As a result, the following conclusions have been derived : The sensitivity and accuracy of the method are reasonably satisfied for the color description of marine sediments; This method can be applied to shipboard color measurements of original wet sediments with careful consideration of variations of these parameters. 11 refs., 5 figs., 5 tabs.

Long distance electron transmission in marine sediment

DEFF Research Database (Denmark)

Risgaard-Petersen, Nils; Nielsen, Lars Peter

processes 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 sul-phides and calcium carbonates in anoxic layers and promotes the formation of Mg-calcite and iron oxides......Geochemical observations in marine sediment have recently shown that electric currents may intimately couple spatially separated biogeochemical processes like oxygen reduction at the sediment surface and hydrogen sul-phide oxidation in anoxic layers centimeters below 1. Further experimental studies...... suggest that the electron conductance is mediated by microorgan-isms. The spatial separation of electron and proton donors and acceptors has major impacts on element cycling by redox processes, pH balances, mineral dissolution/precipitations, and electromigration of ions. The sepa-ration of redox...

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...

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.; Herndl, G.

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

Antarctic marine sediments as fingerprints of pollution migration

International Nuclear Information System (INIS)

Waheed, S.; Ahmad, S.; Rahman, A.; Qureshi, I.H.

2001-01-01

Forty elements in 21 coastal marine sediment samples collected during the second Antarctic scientific expedition from 18 different sites of Brekilen area located at the coast of Antarctica were analysed by instrumental neutron activation analysis (INAA) to detect eventual pollution. Radio-assay schemes for three sets of elements after neutron irradiation and cooling were evolved to avoid matrix effects. Data have been compared with those for sediments of various stations at Antarctica and two other regions in different continents. Lower concentration of certain elements in the Antarctic sediments reflects less environmental exposition. Enrichment factors (EF) were calculated for all the elements using the earth crust as reference matrix, based on elemental values by MASON, TAYLOR and WEDEPOHL which show a normal pattern near to unity expect for Ag and Br. The data obtained could also serve as a reference point from which changes in the global environment can be studied. The quality assurance of data was performed using standard reference materials (SRMs) of a similar matrix (IAEA Marine Sediment SD-M/TM and Chinese Marine Sediment GBW 07313). (author)

Marine sediments as a sink, and contaminated sediments as a diffuse source of radionuclides

International Nuclear Information System (INIS)

Salbu, B.; Borretzen, P.

1997-01-01

Full text: Marine sediments may act as a sink for radionuclides originating from atmospheric fallout (e.g. Chernobyl accident), for radionuclides in discharges from nuclear installations (e.g. Sellafield, UK) for river transported radionuclides, and radionuclides released from nuclear waste dumped at sea (e.g. fjords at Novaya Zemlya). In order to assess short and long term consequences of radionuclides entering the marine ecosystem, the role of sediments as a relatively permanent sink and the potential for contaminated sediments to act as a diffuse source should be focused. The retention of radionuclides in sediments will depend on the source term, i.e. the physico-chemical forms of radionuclides entering the system and on interactions with various sediment components. Radionuclides associated with particles or aggregating polymers are removed from the water phase by sedimentation, while sorption to surface sediment layers is of relevance for ionic radionuclide species including negatively charged colloids. With time, transformation processes will influence the mobility of radionuclides in sediments. The diffusion into mineral lattices will increase fixation, while the influence of for instance red/ox conditions and bio-erosion may mobilize radionuclides originally fixed in radioactive particles. Thus, information of radionuclides species, surface interactions, transformation processes and kinetics is essential for reducing the uncertainties in marine transfer models. Dynamic model experiments where chemically well defined tracers are added to a sea water-marine sediment system are useful for providing information on time dependent interactions and distribution coefficients. When combined with sequential extraction techniques, information on mobility and rate of fixation is subsequently attained. In the present work experimental results from the Irish Sea and the Kara Sea will be discussed

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.

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

Geochemical peculiarities of marine sediment in coastal areas of India

International Nuclear Information System (INIS)

Gothankar, S.S.; Jha, S.K.; Tripathi, R.M.

2014-01-01

To understand the impact of anthropogenic activity on coastal marine environment, sediment samples were collected covering the west and east coast of India. The elemental concentration was determined using EDXRF technique. The east coast showed lower Rb/Sr ratio reflecting higher fraction of biogenic deposits, the higher ratio at the west coast reflects higher fraction of terrigenous detritus. The concentration of Pb and Ni was found higher at Rameshwaram and Okha respectively. The result indicates the impact of land based source of pollutant in few locations due to the anthropogenic activities. (author)

Sampling marine sediments for radionuclide monitoring

International Nuclear Information System (INIS)

Papucci, C.

1997-01-01

A description of the most common devices used for sampling marine sediments are reported. The systems are compared to evidence their intrinsic usefulness, for collecting samples in different environmental conditions or with different scientific objectives. Perturbations and artifacts introduced during the various steps of the sampling procedure are also reviewed, and suggestions are proposed for obtaining and preserving, as much as possible, the representativeness of the sediment samples. (author)

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.

Radionuclide interactions with marine sediments

International Nuclear Information System (INIS)

Higgo, J.J.W.

1987-09-01

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

Quaternary magnetic excursions recorded in marine sediments.

Science.gov (United States)

Channell, J. E. T.

2017-12-01

This year is the golden (50th) anniversary of the first documentation of a magnetic excursion, the Laschamp excursion in volcanics from the Chaine des Puys (Bonhommet and Babkine, 1967). The first recording of an excursion in sediments was from the Blake Outer Ridge (Smith and Foster, 1969). Magnetic excursions are directional aberrations of the geomagnetic field apparently involving short-lived reversal of the main dipole field. They have durations of a few kyrs, and are therefore rarely recorded in sediments with mean sedimentation rates Palma), and 670 ka (Osaka Bay), implying at least 11 excursions in the Brunhes Chron. For the Matuyama Chron, excursions have been recorded in marine sediments at 868 ka (Kamikatsura?), 932 ka (Santa Rosa), 1051 ka (Intra-Jaramillo), 1115 ka (Punaruu), 1255 ka (Bjorn), 1476 ka (Gardar), 1580 ka (Gilsa), and 2737 ka (Porcupine). Excursions coincide with minima in relative paleointensity (RPI) records. Ages are from correlation of excursion records to oxygen isotope records in the same cores, and ice-volume calibration of the oxygen isotope template. The marine sediment record of excursions, combined with independent documentation of excursions in lavas with Ar/Ar age control, is progressively strengthening our knowledge of the excursion inventory in the Quaternary, and enhancing the importance of excursions and RPI in Quaternary stratigraphy.

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

Characterization of marine sediments using analytical techniques

International Nuclear Information System (INIS)

Garcia-Rosales, G.; Longoria-Gandara, L.C.

2011-01-01

This study deals with the characterization of a marine sediments profile from the Gulf of Tehuantepec, Mexico. Ten sediment samples obtained from a core of 18.3 m of length were analysed. Although there have been numerous marine sediments studies carried out in Mexico, more are needed to better understand the sea floor formation. Crystallographic, morphologic, physical, chemical and gamma ray activity analysis were carried out on the samples. The analysis results showed a decrease in organic matter content as a function of sea depth; this value is related to the specific surface area. Some hazardous materials as Cr, Mn, Ni, Sr and Hg were also identified by PIXE in some samples, probably due to anthropogenic activity. The presence of uranium a naturally occurring element was found in all the samples, suggesting a migration through all materials of strata, radioactive elements such as 226 Ra, 235 U, 212 Pb, 214 Pb, 228 Ac, 208 Ti, 214 Bi, 228 Ac and 40 K were detected. (author)

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

Elucidation of 10Be accumulation mechanism to sea floor with the marine sediment

International Nuclear Information System (INIS)

Yoshida, T.; Yamagata, T.; Saito, T.; Nagai, H.; Matsuzaki, H.

2006-01-01

Marine sediment samples (0-30 cm in depth) were collected in the Northwest Pacific Ocean, and South Pacific Ocean during KH00-3 (BO, 7 samples) and KH04-5 (SX, 8 samples) cruise of R/V Hakuho-Maru. The 10 Be concentration in the marine sediment samples range between 0.9x10 9 and 6.5x10 9 atoms/g, and most of the red clay sediment in the Northwest Pacific Ocean showed uniform distribution. The 9 Be concentration in the red clay sediment samples range between 2.3 and 2.6 ppm, which showed a value almost the same as measured 9 Be concentration (1.6-2.3 ppm) in the Chinese loess. The 10 Be concentration in the marine sediment were 20 times higher than the 10 Be concentration (0.2x10 9 atoms/g) in the Chinese loess. These results were suggested that most of 10 Be in the marine sediment were regarded seawater as the origin. (author)

Decomposition of 14C-labeled organic substances in marine sediments

International Nuclear Information System (INIS)

Anon.

1986-01-01

The depth variation of total organic carbon (TOC), organic matter composition and porewater composition in marine sediments suggest that different components of the organic matter undergo decomposition at widely different rates. The decomposition of 14 C-labeled organic substances was followed in sediment microcosms in the laboratory. The substances used were chosen to simulate a portion of material settling to the sediment-water interface (a marine diatom) or hypothesized components of refractory sediment organic matter (melanoidins and a bacterial polymer). The microcosms were found to be good models of the sediment-water interface in terms of how well they mimicked sediment decomposition rates and processes. The decomposition of the labeled material and the natural sediment TOC were monitored over 1 month: the water overlying the sediment remained oxic, and net consumption of nitrate was small. There was no detectable sulfate reduction. The algae and the bacterial polymer were decomposed on average 9x faster than the melanoidins and 90x faster than the natural sediment TOC. The soluble fraction of the algae was decomposed more rapidly than the particulate material

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...... P pump) allows preferential mineralization of the bulk Porg pool relative to Corg during both aerobic and anaerobic respiration and is consistent with the database. Results with this model show that P burial is strongly enhanced in sediments hosting fauna. Animals mix highly labile Porg away from....... The results also help to explain Corg:Porg ratios in the geological record and the persistence of Porg in ancient marine sediments. © 2016 Elsevier Ltd....

Autecology of crenarchaeotal and bacterial clades in marine sediments and microbial mats

OpenAIRE

Kubo, Kyoko

2011-01-01

The focus of this thesis was the autecology of the Miscellaneous Crenarchaeotal Group (MCG), a phylum-level clade of Archaea occurring mostly in marine sediments. Sequences of MCG 16S rRNA genes have been retrieved from a wide range of marine and terrestrial habitats, such as deep subsurface sediments, hydrothermal sediments, mud volcanoes, estuaries, hot springs and freshwater lake sediments. MCG members seem to have no general preferences for a particular temperature or salinity. So far, no...

Observed gas hydrate morphologies in marine sediment

Energy Technology Data Exchange (ETDEWEB)

Holland, M.; Schultheiss, P.; Roberts, J.; Druce, M. [Geotek Ltd., Daventry, Northamptonshire (United Kingdom)

2008-07-01

The morphology of gas hydrate in marine sediments determines the basic physical properties of the sediment-hydrate matrix and provides information regarding the formation of gas hydrate deposits, and the nature of the disruption that will occur on dissociation. Small-scale morphology is useful in estimating the concentrations of gas hydrate from geophysical data. It is also important for predicting their response to climate change or commercial production. Many remote techniques for gas hydrate detection and quantification depend on hydrate morphology. In this study, morphology of gas hydrate was examined in HYACINTH pressure cores from recent seagoing expeditions. Visual and infrared observations from non-pressurized cores were also used. The expeditions and pressure core analysis were described in detail. This paper described the difference between two types of gas hydrate morphologies, notably pore-filling and grain-displacing. Last, the paper addressed the impact of hydrate morphology. It was concluded that a detailed morphology of gas hydrate is an essential component for a full understanding of the past, present, and future of any gas hydrate environment. 14 refs., 4 figs.

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

The Impacts of Episodic Storm and Flood Events on Carbon and Sediment Delivery to Gulf of Mexico Sediments

Science.gov (United States)

Schreiner, K. M.; Carlin, J. A.; Sayers, L.; Swenson, J.

2017-12-01

Marine sediments are an important long-term reservoir for both recently fixed organic carbon (OC) and ancient rock derived OC, much of which is delivered by rivers. The ratio between these two sources of OC in turn regulates atmospheric levels of oxygen and carbon dioxide over geologic time, making this riverine delivery of OC, primarily carried by sediments, an important flux in the global carbon cycle. However, while the overall magnitude of these fluxes are relatively well known, it remains to be determined the importance of episodic events, like storms and floods, in the flux of OC from terrestrial to marine environments. Here, we present data from a 34 cm core collected from the Gulf of Mexico at a mid-shelf distal depocenter for the Brazos River in 2015, during a strong El Nino when that area of the country was experiencing 100-year flood events and anomalously high river flow. Based on analysis of the radioactive isotope 7Be, approximately the top 7-8 cm of the sediment in this core was deposited during this flood event. Both bulk elemental (C, N, and stable carbon isotopes) and chemical biomarker (lignin-phenol) data has been combined to provide information of the origin and chemistry of the OC in this core both before and during flooding. C:N and d13C indicate a mixture of marine-sourced and terrestrially-sourced OC throughout the length of the core with very little variation between the flood layer and deeper sediments. However, lignin-phenol concentrations are higher in flood-deposited sediment, indicating that this sediment is likely terrestrially-sourced. Lignin-phenol indicators of OC degradation state (Acid:Aldehyde ratios) indicate that flood sediment is fresher and less degraded than deeper sediments. Taken together, these results indicate that 1. Bulk analyses are not enough to determine OC source and the importance of flood events in OC cycling and 2. Episodic events like floods could have an oversized impact on OC storage in marine sediments.

Effects of Feeding Strategy, Sediment Characteristics, and Chemical Properties on Polychlorinated Biphenyl and Polybrominated Diphenyl Ether Bioaccumulation from Marine Sediments in Two Invertebrates.

Science.gov (United States)

Frouin, H; Jackman, P; Dangerfield, N D; Ross, P S

2017-08-01

Shellfish and sediment invertebrates have been widely used to assess pollution trends over space and time in coastal environments around the world. However, few studies have compared the bioaccumulation potential of different test species over a range of sediment-contaminant concentrations and profiles. The bioavailability of sediment-related contaminants was evaluated using sediments collected from sites (n = 12) throughout the Salish Sea, British Columbia, Canada. Two benthic marine invertebrates-the Baltic clam Macoma balthica and the polychaete worm Neanthes arenaceodentata-were exposed for 28 days in a controlled environment to these field-collected coastal sediments. The congener-specific uptake of legacy polychlorinated biphenyls (PCBs) and emergent polybrominated diphenyl ethers (PBDEs) was determined using high-resolution gas chromatography/mass spectrometry in sediments and in invertebrates after the experimental exposure. The polychaete Neanthes accumulated lower concentrations of PCBs but higher concentrations of PBDEs. The present study indicates that differences in bioaccumulation between these two invertebrates shape the accumulation of PCB and PBDE congeners, reflect differences in feeding strategies, and reveal the physicochemical properties of the contaminants and sediment properties. Because biota-sediment accumulation factor values are often calculated for environmental monitoring or site-specific impact assessments, our results provide insight into potentially confounding factors and the need for caution when selecting indicator species for coastal marine pollution.

World wide intercomparison of trace element measurements in marine sediments SD-M-2/TM

International Nuclear Information System (INIS)

Mee, L.D.; Oregioni, B.

1991-09-01

The accurate and precise determination of trace elements in marine sediments is an important aspect of geochemical studies of the marine environment and for assessing the levels and pathways of marine pollutants. Past intercomparison studies conducted by the Marine Environment Laboratory of IAEA (formerly the International Laboratory of Marine Radioactivity) have focussed upon near-shore marine sediments where trace metal contamination is frequently observed. The present exercise was designed to study a typical oxidised deep-sea sediment characterized by a preponderance of fine particle clays. Analysis of such material is a routine matter for most geochemists but represents a ''baseline sample'' for marine pollution chemists. The present exercise represented a unique opportunity for chemists worldwide to intercompare their analytical methodologies for deep-sea sediments. By statistically examining the data from this study, the material can be certified for future use as a reference material - apparently the only one of its kind available throughout the world. 6 refs, figs and tabs

Sediment and contaminant transport in a marine environment

International Nuclear Information System (INIS)

Onishi, Y.; Thompson, F.L.

1986-01-01

The finite-element model FETRA is an unsteady, verically averaged two-dimensional model to simulate the transport of sediment and contaminants (radionuclides, heavy metals, pesticides, etc.) in coastal and estuarine water. The model, together with the hydrodynamic model CAFE-I, was applied to the Irish Sea to predict the migration and accumulation of sediment (both cohesive and noncohesive) and of a radionuclide (dissolved and sediment-sorbed) in a tide- and wind-driven system. The study demonstrated that FETRA is a useful tool for assessing sediment and toxic contaminant transport in a marine environment

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

2017-11-01

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

Global diffusive fluxes of methane in marine sediments

Science.gov (United States)

Egger, Matthias; Riedinger, Natascha; Mogollón, José M.; Jørgensen, Bo Barker

2018-06-01

Anaerobic oxidation of methane provides a globally important, yet poorly constrained barrier for the vast amounts of methane produced in the subseafloor. Here we provide a global map and budget of the methane flux and degradation in diffusion-controlled marine sediments in relation to the depth of the methane oxidation barrier. Our new budget suggests that 45-61 Tg of methane are oxidized with sulfate annually, with approximately 80% of this oxidation occurring in continental shelf sediments (methane in steady-state diffusive sediments, we calculate that 3-4% of the global organic carbon flux to the seafloor is converted to methane. We further report a global imbalance of diffusive methane and sulfate fluxes into the sulfate-methane transition with no clear trend with respect to the corresponding depth of the methane oxidation barrier. The observed global mean net flux ratio between sulfate and methane of 1.4:1 indicates that, on average, the methane flux to the sulfate-methane transition accounts for only 70% of the sulfate consumption in the sulfate-methane transition zone of marine sediments.

Certification of Trace Element Mass Fractions in IAEA-457 Marine Sediment Sample

International Nuclear Information System (INIS)

2013-01-01

The primary goal of the IAEA Environment Laboratories in Monaco (NAEL) is to help Member States understand, monitor and protect the marine environment. The major impact exerted by large coastal cities on marine ecosystems is therefore of great concern to the IAEA and its Environment Laboratories. Given that marine pollution assessments of such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments, the NAEL has assisted national laboratories and regional laboratory networks through its Reference Products for Environment and Trade programme since the early 1970s. Quality assurance (QA), quality control (QC) and associated good laboratory practice are essential components of all marine environmental monitoring studies. QC procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess reliability and comparability of measurement data. QA can be realized by participation in externally organized laboratory performance studies, also known as interlaboratory comparisons, which compare and evaluate analytical performance and measurement capabilities of participating laboratories. Data that are not based on adequate QA/QC can be erroneous and their misuse can lead to incorrect environmental management decisions. A marine sediment sample with certified mass fractions for Ag, Al, As, Cd, Cr, Co, Cu, Fe, Hg, Li, Mn, Ni, Pb, Sn, Sr, V and Zn was recently produced by the NAEL in the frame of a project between the IAEA and the Korea Institute of Ocean Science and Technology. This report describes the sample preparation methodology, the material homogeneity and stability study, the selection of laboratories, the evaluation of results from the certification campaign and the assignment of property values and their associated uncertainty. As a result, reference values for mass fractions and associated expanded

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.

Salinity shifts in marine sediment: Importance of number of fluctuation rather than their intensities on bacterial denitrifying community.

Science.gov (United States)

Zaghmouri, Imen; Michotey, Valerie D; Armougom, Fabrice; Guasco, Sophie; Bonin, Patricia C

2018-05-01

The sensitivity of denitrifying community to salinity fluctuations was studied in microcosms filled with marine coastal sediments subjected to different salinity disturbances over time (sediment under frequent salinity changes vs sediment with "stable" salinity pattern). Upon short-term salinity shift, denitrification rate and denitrifiers abundance showed high resistance whatever the sediment origin is. Denitrifying community adapted to frequent salinity changes showed high resistance when salinity increases, with a dynamic nosZ relative expression level. Marine sediment denitrifying community, characterized by more stable pattern, was less resistant when salinity decreases. However, after two successive variations of salinity, it shifted toward the characteristic community of fluctuating conditions, with larger proportion of Pseudomonas-nosZ, exhibiting an increase of nosZ relative expression level. The impact of long-term salinity variation upon bacterial community was confirmed at ribosomal level with a higher percentage of Pseudomonas and lower proportion of nosZII clade genera. Copyright © 2018 Elsevier Ltd. All rights reserved.

Presence of uranium and plutonium in marine sediments from gulf of Tehuantepec, Mexico

International Nuclear Information System (INIS)

Ordonez-Regil, E.; Almazan-Torres, M.G.; Sanchez-Cabeza, J.A.; Ruiz-Fernandez, A.C.

2013-01-01

Uranium and plutonium were determined in the Tehua II-21 sediment core collected from the Gulf of Tehuantepec, Mexico. The analyses were performed using radiochemical separation and alpha spectroscopy. Activity concentrations of alpha emitters in the sediment samples were from 2.56 to 43.1 Bq/kg for 238 U, from 3.15 to 43.1 Bq/kg for 234 U and from 0.69 to 2.95 Bq/Kg for 239+240 Pu. Uranium activity concentration in marine sediment studied is generally high compared with those found in sediments from other marine coastal areas in the world. The presence of relatively high concentrations of anthropogenic plutonium in the sediments from the Gulf of Tehuantepec suggests that anthropogenic radionuclides have been incorporated and dispersed into the global marine environment. (author)

Assessment of the potential impact of the phosphate industry along the Syrian Coast by evaluating 210Po and 210Pb levels in sediment, seawater and selected marine organisms

International Nuclear Information System (INIS)

Al-Masri, S.; Mamish, S.

2000-12-01

Phosphate industry is considered to be one of the potential sources of natural radionuclides in Syrian environment. Most of the phosphate ore is exported in large quantities via one of the main Syrian ports (Tartous) situated on the east coast of the Mediterranean Sea (34 54 North , 35 52 East). The impact of the loading cargoes on the marine environment has been evaluated. 210 Po and 210 Pb in seawater, sediment and marine organisms have been determined. Results have shown a significant enhancement of these two radionuclides in sediment and surface water inside the port area. The highest 210 Po and 210 Pb concentrations observed in sediment were found to be 170 Bq.kg -1 and 64 Bq.kg -1 respectively. While, 210 Pb and 210 Po concentrations in surface water ranged from 5 to 20 m Bq.l -1 and 0.93 to 3.23 m Bq.l -1 . In addition, other naturally occurring radionuclides were also determined in the collected sediment samples and relatively higher values ( 226 Ra = 33.2 Bq.kg -1 and 234 Th = 88 Bq.kg -1 ) were observed for those samples collected from inside the port. However, the effect of loading cargoes on the near marine environment was found to be mainly related to wind direction where air particulate carrying radioactivity either being blown to lands or sea. Moreover, comparable values of 210 Po and 210 Pb for all marine organisms (algae, crab and fish) have been observed and it is not recommended to use these organisms for evaluating the effect of phosphate industry on marine environment. This is due to the fact that marine organisms accumulate 210 Po and 210 Pb in their body. Two core samples were also collected in order to investigate the history of pollution in the port. Results have shown a complex relation for unsupported 210 Pb with depth, where the constant supply dating method can not be applied. This is due to the fact that two sources for unsupported 210 Pb being observed in the port area; viz. radon gas and phosphate dust carrying radioactivity

Experimental investigation on consistency limits of cement and lime-stabilized marine sediments.

Science.gov (United States)

Wang, DongXing; Zentar, Rachid; Abriak, Nor Edine; Xu, WeiYa

2012-06-01

This paper presents the effects of treatments with cement and lime on the consistency limits of marine sediments dredged from Dunkirk port. The Casagrande percussion test and the fall cone test were used to determine the liquid limits of raw sediments and treated marine sediments. For the evaluation of the plastic limits, the results of the fall cone test were compared with those obtained by the rolling test method. The relationship between the water contents and the penetration depths for the determination of the liquid limit and the plastic limit was explored. Liquid limits at 15.5 mm and plastic limits at 1.55 mm seem to be a more appropriate choice for the studied marine sediments compared with the limits determined by other used prediction methods. Finally, the effect of cement treatment and lime treatment on the Casagrande classification of the studied sediments was investigated according to the different prediction results.

Measurement of uranium and thorium in marine sediments

International Nuclear Information System (INIS)

Denden, Ibtihel

2009-01-01

Lakes, oceans and seas accumulate sediments. These sediments constitute a file of the last environmental conditions going up in some cases to thousands of years. In our study, we consulted this file by analyzing radioisotopes of Uranium and Thorium that are included in a carrot of marine sediment taken from the south of Mediterranean Sea. When we applied the technique developed by the maritime environment's laboratory of Monaco, we found spectra with bad resolutions. For this reason, the optimization of this protocol appeared necessary. (Author).

Neutron activation analysis studies of marine biological species and related marine sediments

International Nuclear Information System (INIS)

Guinn, V.P.; Di Casa, M.; de Goeij, J.J.M.; Young, D.R.

1974-01-01

To assess the effects, if any, of elemental pollution of the Pacific Ocean from the major Southern California sewage outfalls, samples of ocean sediments were obtained and specimens of Dover Sole were caught in a number of locations. Liver tissue samples from Dover Sole specimens were analyzed for 12 elements and sediment samples for 4 elements. Although a number of the elements were highly concentrated in the surface sediments in the heavily-polluted areas, the Dover Sole showed no evidence of picking up any of the 12 elements from these polluted sediments. Sediment profiles, versus depth, (0-34 cm) were also determined for As, Sb, Se, and Hg. Stemming partly from the results of the NSF Baseline Study, the Southern California Coastal Water Research Project (SCCWRP) became interested in a more intensive multi-element study of marine biological species and ocean sediments off the coast of Southern California. The purpose of this study was to assess the effects, if any, of a number of selected elements of interest being discharged into the Pacific Ocean from the principal sewage outfalls in the Southern California (Los Angeles) area upon marine biological species. The 12 elements selected for study were Cr, Fe, Co, Cu, Zn, As, Se, Mo, Ag, Cd, Sb, and Hg. Since a number of these elements were not amenable to purely instrumental NAA measurements, a suitable post-irradiation radiochemical separation procedure was devised, thoroughly tested, and then applied to 39 samples of liver tissue from specimens of Dover Sole caught in non-polluted, slightly-polluted, fairly-polluted, and heavily-polluted areas along the coast. A number of surface sediment samples from these same locations were also analyzed, by both instrumental and radiochemical NAA. In the following sections, the samples analyzed are cited, the procedures developed and employed are described, the results obtained are presented, and the conclusions reached are discussed

Occurrence and sorption properties of arsenicals in marine sediments

DEFF Research Database (Denmark)

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

2013-01-01

in 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......The content of total arsenic, the inorganic forms: arsenite (As(III)) and arsenate (As(V)), the methylated forms: monomethylarsonic acid and dimethylarsinic acid (DMA), trimethylarsenic oxide, tetramethylarsenonium ion and arsenobetaine was measured in 95 sediment samples and 11 pore water samples...... in the Baltic Sea and other parts of the world. Existing data for on-site measurements of sorption coefficients (Kd) of arsenicals in marine and freshwater sediments show large variability from 1,000 L/kg. In this work, calculated sorption coefficients (Kd and Koc) for As(III+V) showed significant correlation...

Environmental Impact of Tributyltin-Resistant Marine Bacteria in the Indigenous Microbial Population of Tributyltin-Polluted Surface Sediments.

Science.gov (United States)

Mimura, Haruo; Yagi, Masahiro; Yoshida, Kazutoshi

2017-01-01

　We compared the TBT-resistant ability of resting cells prepared from isolates that formed colonies on nutrient agar plates containing 100 µM tributyltin (TBT) chloride, such as Photobacterium sp. TKY1, Halomonas sp. TKY2, and Photobacterium sp. NGY1, with those from taxonomically similar type strains. Photobacterium sp. TKY1 showed the highest ability among those three isolates. The number of surviving Photobacterium sp. TKY1 cells was hardly decreased after 1 h of exposure to 100 µM TBTCl, regardless of the number of resting cells in the range from 10 9.4 to 10 4.2 CFU mL -1 . In such an experimental condition, the maximum number of TBT molecules available to associate with a single cell was estimated to be approximately 6.0 x 10 11.8 . Resting cells prepared from type strains Photobacterium ganghwense JCM 12487 T and P. halotolerans LMG 22194 T , which have 16S rDNA sequences highly homologous with those of Photobacterium sp. TKY1, showed sensitivity to TBT, indicating that TBT-resistant marine bacterial species are not closely related in spite of their taxonomic similarity. We also estimated the impact of TBT-resistant bacterial species to indigenous microbial populations of TBT-polluted surface sediments. The number of surviving TBT-sensitive Vibrio natriegens ATCC 14048 T cells, 10 6.2±0.3 CFU mL -1 , was reduced to 10 4.4±0.4 CFU mL -1 when TBT-resistant Photobacterium sp. TKY1 cells, 10 9.1±0.2 CFU mL -1 , coexisted with 10 9.4±0.2 CFU mL -1 of V. natriegens ATCC 14048 T cells in the presence of 100 µM TBTCl. These results indicate that the toxicity of TBT to TBT-sensitive marine bacterial populations might be enhanced when a TBT-resistant marine bacterial species inhabits TBT-polluted surface sediments.

Necromass as a source of energy to microorganisms in marine sediments.

Science.gov (United States)

Bradley, J.; Amend, J.; LaRowe, D.

2017-12-01

Marine sediments constitute one of the largest, most energy-limited biospheres on Earth. Despite increasing exploration and interest characterizing microbial communities in marine sediments, the production and role of microbial dead-matter (necromass) has largely been overlooked. Necromass is produced on a global scale, yet its significance as a power source to heterotrophic microorganisms remains unknown. We developed a physical, bio-energetic and geochemical model to quantify the total power supply from necromass oxidation and the total power demand of living microorganisms in marine sediments. This model is first applied to sediments from the oligotrophic South Pacific Gyre (SPG), where organic carbon and biomass concentrations are extremely low, yet microorganisms persist for millions of years in some of the lowest energy states on Earth. We show that necromass does not supply sufficient power to support the total demands of the living community (maintenance demands of microorganisms in marine sediments for up to 60,000 years following burial. Our model assumes that all counted cells are viable. Yet, if only a fraction of counted cells are alive, the role of necromass as an electron donor in fueling microbial metabolisms is even greater. This new insight requires a reassessment of carbon fluxes in the deep biosphere. By extension, we also demonstrate a mechanism for microbial communities to persist by oxidizing necromass over geological timescales, and thereby endure unfavorable, low-energy settings that might be analogous to conditions on early Earth and on other planetary bodies.

Phosphorus sorption on marine carbonate sediment: phosphonate as model organic compounds.

Science.gov (United States)

Huang, Xiao-Lan; Zhang, Jia-Zhong

2011-11-01

Organophosphonate, characterized by the presence of a stable, covalent, carbon to phosphorus (C-P) bond, is a group of synthetic or biogenic organophosphorus compounds. The fate of these organic phosphorus compounds in the environment is not well studied. This study presents the first investigation on the sorption of phosphorus (P) in the presence of two model phosphonate compounds, 2-aminothylphosphonoic acid (2-AEP) and phosphonoformic acid (PFA), on marine carbonate sediments. In contrast to other organic P compounds, no significant inorganic phosphate exchange was observed in seawater. P was found to adsorb on the sediment only in the presence of PFA, not 2-AEP. This indicated that sorption of P from phosphonate on marine sediment was compound specific. Compared with inorganic phosphate sorption on the same sediments, P sorption from organic phosphorus is much less in the marine environment. Further study is needed to understand the potential role of the organophosphonate compounds in biogeochemical cycle of phosphorus in the environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

Biogeochemistry of pyrite and iron sulfide oxidation in marine sediments

DEFF Research Database (Denmark)

Schippers, A.; Jørgensen, BB

2002-01-01

as substrates and NO3- as electron acceptor, in the presence of (FeS2)-Fe-55, to test for co-oxidation of FeS2, but an anaerobic microbial dissolution of (FeS2)-Fe-55, could not been detected. FeS2 and FeS were not oxidized by amorphous Fe(III) oxide in the presence of Fe-complexing organic compounds......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...... marine sediments and incubated at different temperatures for > 1 yr. Bacteria could not be enriched with FeS2 as substrate or with FeS and amorphous Fe(III) oxide. With FeS and NO3-, 14 enrichments were obtained. One of these enrichments was further cultivated anaerobically with Fe2+ and S-0...

Certification of Trace Elements and Methyl Mercury Mass Fractions in IAEA-456 Marine Sediment Samples

International Nuclear Information System (INIS)

2016-01-01

The primary goal of the IAEA Environment Laboratories is to assist Member States in the use of both stable and radioisotope analytical techniques to understand, monitor and protect the environment. In this context, the major impact of large coastal cities on marine ecosystems is an issue of prime concern for the IAEA and the IAEA Environment Laboratories. The marine pollution assessments required to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. The IAEA Environment Laboratories has been assisting national laboratories and regional laboratory networks since the early 1970s through the provision of a reference material programme for the analysis of radionuclides, trace elements and organic compounds in marine samples. Quality assurance, quality control and associated good laboratory practice are essential components of all marine environmental monitoring studies. Quality control procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess t h e reliability and comparability of measurement data. Data that are not based on adequate quality assurance and quality control can be erroneous, and their misuse can lead to poor environmental management decisions. A marine sediment sample with certified mass amount contents for aluminium, arsenic, cadmium chromium, cobalt, copper, iron, lead, mercury, methyl mercury, manganese, nickel, vanadium and zinc was recently produced by the IAEA Environment Laboratories. This publication presents the sample preparation methodology, including material homogeneity and the stability study, the selection of laboratories, the evaluation of results from the certification campaign, and the assignment of property values and their associated uncertainty. As a result, certified values for mass fractions and associated expanded uncertainty were

Avalanches of sediment form deep-marine depositions

NARCIS (Netherlands)

Pohl, Florian|info:eu-repo/dai/nl/34309424X

2017-01-01

The deep ocean is the largest sedimentary system basin on the planet. It serves as the primary storage point for all terrestrially weathered sediment that makes it beyond the near-shore environment. These deep-marine offshore deposits have become a focus of attention in exploration due to the

Tsunami induced transportation of the coastal marine sediments to distant onshore regions: Some indications from foraminiferal and microbenthic studies of new Wandoor region (Andaman & Nicobar)

Digital Repository Service at National Institute of Oceanography (India)

Khare, N.; Chaturvedi, S.K.; Ingole, B.S.

regions near New Wandoor (Andaman and Nicobar) suggested the areal extent of marine transgression due to tsunami waves on December 26, 2004. There is a need to investigate coastal marine sediments with multi-disciplinary approach to understnd impact...

Effect of sediment properties on the sorption of C12-2-LAS in marine and estuarine sediments

NARCIS (Netherlands)

Rico Rico, A.; Temara, A.; Behrends, T.; Hermens, J.L.M.

2009-01-01

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

Contamination of port zone sediments by metals from Large Marine Ecosystems of Brazil.

Science.gov (United States)

Buruaem, Lucas M; Hortellani, Marcos A; Sarkis, Jorge E; Costa-Lotufo, Leticia V; Abessa, Denis M S

2012-03-01

Sediment contamination by metals poses risks to coastal ecosystems and is considered to be problematic to dredging operations. In Brazil, there are differences in sedimentology along the Large Marine Ecosystems in relation to the metal distributions. We aimed to assess the extent of Al, Fe, Hg, Cd, Cr, Cu, Ni, Pb and Zn contamination in sediments from port zones in northeast (Mucuripe and Pecém) and southeast (Santos) Brazil through geochemical analyses and sediment quality ratings. The metal concentrations found in these port zones were higher than those observed in the continental shelf or the background values in both regions. In the northeast, metals were associated with carbonate, while in Santos, they were associated with mud. Geochemical analyses showed enrichments in Hg, Cd, Cu, Ni and Zn, and a simple application of international sediment quality guidelines failed to predict their impacts, whereas the use of site-specific values that were derived by geochemical and ecotoxicological approaches seemed to be more appropriate in the management of the dredged sediments. Copyright © 2012 Elsevier Ltd. All rights reserved.

The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study

DEFF Research Database (Denmark)

Bonaglia, Stefano; Hylén, Astrid; Rattray, Jane E.

2017-01-01

Given the increasing impacts of human activities on global nitrogen (N) cycle, investigations on N transformation processes in the marine environment have drastically increased in the last years. Benthic N cycling has mainly been studied in anthropogenically impacted estuaries and coasts, while its...... sediments worldwide (range 34–344 µmol N m−2 d−1). Anammox accounted for 18–26 % of the total N2 production. Absence of free hydrogen sulfide and low concentrations of dissolved iron in sediment pore waters suggested that denitrification and DNRA were driven by organic matter oxidation rather than...... chemolithotrophy. DNRA was as important as denitrification at a shallow, coastal station situated in the northern Bothnian Bay. At this pristine and fully oxygenated site, ammonium regeneration through DNRA contributed more than one third to the total dissolved nitrogen (TDN) diffusing from the sediment...

Impacts of metal and metal oxide nanoparticles on marine organisms

International Nuclear Information System (INIS)

Baker, Tony J.; Tyler, Charles R.; Galloway, Tamara S.

2014-01-01

Increasing use of metal and metal oxide nanoparticles [Me(O)NPs] in products means many will inevitably find their way into marine systems. Their likely fate here is sedimentation following hetero-aggregation with natural organic matter and/or free anions, putting benthic, sediment-dwelling and filter feeding organisms most at risk. In marine systems, Me(O)NPs can absorb to micro-organisms with potential for trophic transfer following consumption. Filter feeders, especially bivalves, accumulate Me(O)NPs through trapping them in mucus prior to ingestion. Benthic in-fauna may directly ingest sedimented Me(O)NPs. In fish, uptake is principally via the gut following drinking, whilst Me(O)NPs caught in gill mucus may affect respiratory processes and ion transport. Currently, environmentally-realistic Me(O)NP concentrations are unlikely to cause significant adverse acute health problems, however sub-lethal effects e.g. oxidative stresses have been noted in many organisms, often deriving from dissolution of Ag, Cu or Zn ions, and this could result in chronic health impacts. -- Highlights: • Nanoparticle (NP) use increasing, and NPs ultimately discharged to marine systems. • Metal ion dissolution from NPs causes oxidative stress at relevant concentrations. • Bioaccumulation and trophic transfer of NPs likely at all levels of marine food webs. • Biofilms and filter feeders are major NP accumulators, but many Classes lack study. • Current release levels unlikely to cause chronic damage, but may be a future issue. -- Exposure to metal (oxide) nanoparticles causes sub-lethal effects in marine organisms, the extent of which is related principally to the organisms' feeding regime, habitat and lifestyle

Increased carbon uptake in marine sediment enabled by naturally occurring electrical conductors

Science.gov (United States)

Nielsen, M. E.; Cahoon, D. P.; Girguis, P. R.

2011-12-01

Reduction-oxidation (redox) gradients are common across marine sediment-water interfaces and result from microbially-mediated reactions such as the oxidation of organic matter coupled to reduction of electron acceptors. Most microbes living in sediments do not have direct access to oxygen in their immediate environment, however it has recently been shown that sulfide-oxidizing microbes may employ extracellular electron transfer (EET) to couple the oxidation of sulfide in the anoxic zone to reduction of oxygen at the sediment-water interface located several centimeters away. However, no mechanisms for this observed phenomenon have been validated. Accordingly, we tested the hypothesis that conductive minerals in marine sediment (specifically pyrite) can couple spatially separated redox reactions such as anaerobic respiration and oxygen reduction. Marine sediment was amended with naturally occurring pyrite in varying concentrations (0, 2, 10 and 50 weight-percent) and then incubated with 10 μM 13C-labeled acetate. After six hours, the treatments with the greatest amount of added pyrite showed the greatest incorporation of acetate from the labeled pool. The fraction of labeled acetate incorporation more than doubled in the 10 and 50 weight-percent treatments compared to the control sediment. We also designed a circuit to investigate the electrical conductivity of the sediment treatments as a function of added pyrite. A potentiostat was used to establish a known voltage across a sediment column and current was measured. Resistance (the inverse of conductance) was calculated from a linear fit of current data over a range of voltages ranging from 0.5 to 1.0 V. The treatments with added pyrite had lower resistance than background sediment, with the lowest resistance corresponding to the 50% pyrite treatment. We also examined the effect of varying pyrite content on microbial community composition using massively parallel 16S rRNA sequencing. Microbial community analyses

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-11-15

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

Temporal variation on environmental variables and pollution indicators in marine sediments under sea Salmon farming cages in protected and exposed zones in the Chilean inland Southern Sea.

Science.gov (United States)

Urbina, Mauricio A

2016-12-15

The impacts of any activity on marine ecosystems will depend on the characteristics of the receptor medium and its resilience to external pressures. Salmon farming industry develops along a constant gradient of hydrodynamic conditions in the south of Chile. However, the influence of the hydrodynamic characteristics (weak or strong) on the impacts of intensive salmon farming is still poorly understood. This one year study evaluates the impacts of salmon farming on the marine sediments of both protected and exposed marine zones differing in their hydrodynamic characteristics. Six physico-chemical, five biological variables and seven indexes of marine sediments status were evaluated under the salmon farming cages and control sites. Our results identified a few key variables and indexes necessary to accurately evaluate the salmon farming impacts on both protected and exposed zones. Interestingly, the ranking of importance of the variables and the temporality of the observed changes, varied depending on the hydrodynamic characteristics. Biological variables (nematodes abundance) and environmental indexes (Simpson's dominance, Shannon's diversity and Pielou evenness) are the first to reflect detrimental impacts under the salmon farming cages. Then the physico-chemical variables such as redox, sulphurs and phosphorus in both zones also show detrimental impacts. Based on the present results we propose that the hydrodynamic regime is an important driver of the magnitude and temporality of the effects of salmon farming on marine sediments. The variables and indexes that best reflect the effects of salmon farming, in both protected and exposed zones, are also described. Copyright © 2016. Published by Elsevier B.V.

V isotope composition in modern marine hydrothermal sediments

Science.gov (United States)

Wu, F.; Owens, J. D.; Nielsen, S.; German, C. R.; Rachel, M.

2017-12-01

Vanadium is multivalence transition metal with two isotopes (51V and 50V). Recent work has shown that large V isotope variations occur with oxygen variations in modern sediments (Wu et al., 2016 and 2017 Goldschmidt Abstracts), providing its potential as a promising proxy for determining low oxygen conditions. However, the development of V isotopes as a proxy to probe past redox conditions requires a comprehensive understanding of the modern oceanic isotopic mass balance. Therein, the scavenging of V from the hydrous iron oxides in hydrothermal fluid has been shown to be an important removal process from seawater (Rudnicki and Elderfield, 1993 GCA) but remains unquantified. In this study, we analyzed V isotopic compositions of metalliferous sediments around the active TAG hydrothermal mound from the mid-Atlantic Ridge (26° degrees North) and the Eastern Pacific Zonal Transect (GEOTRACES EPZT cruise GP16). The TAG sediments deposited as Fe oxyhydroxides from plume fall-out, and have δ51V values between -0.3 to 0‰. The good correlation between Fe and V for these metalliferous sediments indicate that the accumulation of V in these samples is directly related to the deposition of Fe oxyhydroxides, which also control their V isotope signature. The EPZT samples cover 8,000 km in the South Pacific Ocean with sedimentary areas that underlie the Peru upwelling region and the well-oxygenated deep South Pacific Ocean influenced by hydtorthermal plume material from southern East Pacific Rise (EPR). The sediments collected at the east of the EPR have δ51V values between -1.2 to -0.7‰, similar to previous δ51V of oxic sediments. In contrast, the sediments from the west of the EPR have δ51V values (-0.4 to 0‰) similar to hydrothermal sediments from the mid-Atlantic Ridge, indicating the long transportation (more than 4,000 km, Fitzsimmons et al., 2017 NG) of Fe and Mn from hydrothermal plume and their incorporation into sediments have a major impact on the cycle of V

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

International Nuclear Information System (INIS)

Nazaratul Ashifa Abdullah Salim; Mohd Suhaimi Hamzah; Mohd Suhaimi Elias; Siong, W.B.; Shamsiah Abdul Rahman; Azian Hashim; Shakirah Abdul Shukor

2013-01-01

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

Microbial Diversity in Sulfate-Reducing Marine Sediment Enrichment Cultures Associated with Anaerobic Biotransformation of Coastal Stockpiled Phosphogypsum (Sfax, Tunisia

Directory of Open Access Journals (Sweden)

Hana Zouch

2017-08-01

Full Text Available Anaerobic biotechnology using sulfate-reducing bacteria (SRB is a promising alternative for reducing long-term stockpiling of phosphogypsum (PG, an acidic (pH ~3 by-product of the phosphate fertilizer industries containing high amounts of sulfate. The main objective of this study was to evaluate, for the first time, the diversity and ability of anaerobic marine microorganisms to convert sulfate from PG into sulfide, in order to look for marine SRB of biotechnological interest. A series of sulfate-reducing enrichment cultures were performed using different electron donors (i.e., acetate, formate, or lactate and sulfate sources (i.e., sodium sulfate or PG as electron acceptors. Significant sulfide production was observed from enrichment cultures inoculated with marine sediments, collected near the effluent discharge point of a Tunisian fertilizer industry (Sfax, Tunisia. Sulfate sources impacted sulfide production rates from marine sediments as well as the diversity of SRB species belonging to Deltaproteobacteria. When PG was used as sulfate source, Desulfovibrio species dominated microbial communities of marine sediments, while Desulfobacter species were mainly detected using sodium sulfate. Sulfide production was also affected depending on the electron donor used, with the highest production obtained using formate. In contrast, low sulfide production (acetate-containing cultures was associated with an increase in the population of Firmicutes. These results suggested that marine Desulfovibrio species, to be further isolated, are potential candidates for bioremediation of PG by immobilizing metals and metalloids thanks to sulfide production by these SRB.

Bioturbation: impact on the marine nitrogen cycle.

Science.gov (United States)

Laverock, Bonnie; Gilbert, Jack A; Tait, Karen; Osborn, A Mark; Widdicombe, Steve

2011-01-01

Sediments play a key role in the marine nitrogen cycle and can act either as a source or a sink of biologically available (fixed) nitrogen. This cycling is driven by a number of microbial remineralization reactions, many of which occur across the oxic/anoxic interface near the sediment surface. The presence and activity of large burrowing macrofauna (bioturbators) in the sediment can significantly affect these microbial processes by altering the physicochemical properties of the sediment. For example, the building and irrigation of burrows by bioturbators introduces fresh oxygenated water into deeper sediment layers and allows the exchange of solutes between the sediment and water column. Burrows can effectively extend the oxic/anoxic interface into deeper sediment layers, thus providing a unique environment for nitrogen-cycling microbial communities. Recent studies have shown that the abundance and diversity of micro-organisms can be far greater in burrow wall sediment than in the surrounding surface or subsurface sediment; meanwhile, bioturbated sediment supports higher rates of coupled nitrification-denitrification reactions and increased fluxes of ammonium to the water column. In the present paper we discuss the potential for bioturbation to significantly affect marine nitrogen cycling, as well as the molecular techniques used to study microbial nitrogen cycling communities and directions for future study.

Certification of Trace Element Mass Fractions in IAEA-458 Marine Sediment Sample

International Nuclear Information System (INIS)

2013-01-01

The primary goal of the IAEA Environment Laboratories (NAEL) is to help Member States understand, monitor and protect the marine environment. The major impact exerted by large coastal cities on marine ecosystems is therefore of great concern to the IAEA and its Environment Laboratories. Given that marine pollution assessments of such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments, the NAEL has assisted national laboratories and regional laboratory networks through its Reference Products for Environment and Trade programme since the early 1970s. Quality assurance (QA), quality control (QC) and associated good laboratory practice are essential components of all marine environmental monitoring studies. QC procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess reliability and comparability of measurement data. QA can be realized by participation in externally organized laboratory performance studies, also known as interlaboratory comparisons, which compare and evaluate the analytical performance and measurement capabilities of participating laboratories. Data that are not based on adequate QA/QC can be erroneous, and their misuse can lead to incorrect environmental management decisions. This report describes the sample preparation methodology, material homogeneity and stability study, selection of laboratories, evaluation of results from the certification campaign and assignment of property values and their associated uncertainty. As a result, reference values for mass fractions and associated expanded uncertainty for 16 trace elements (Al, As, Cd, Cr, Co, Cu, Fe, Hg, Li, Mn, Ni, Pb, Sr, Sn, V and Zn) in marine sediment were established

The physical impacts of microplastics on marine organisms: A review

International Nuclear Information System (INIS)

Wright, Stephanie L.; Thompson, Richard C.; Galloway, Tamara S.

2013-01-01

Plastic debris at the micro-, and potentially also the nano-scale, are widespread in the environment. Microplastics have accumulated in oceans and sediments worldwide in recent years, with maximum concentrations reaching 100 000 particles m 3 . Due to their small size, microplastics may be ingested by low trophic fauna, with uncertain consequences for the health of the organism. This review focuses on marine invertebrates and their susceptibility to the physical impacts of microplastic uptake. Some of the main points discussed are (1) an evaluation of the factors contributing to the bioavailability of microplastics including size and density; (2) an assessment of the relative susceptibility of different feeding guilds; (3) an overview of the factors most likely to influence the physical impacts of microplastics such as accumulation and translocation; and (4) the trophic transfer of microplastics. These findings are important in guiding future marine litter research and management strategies. -- Highlights: •Accumulation of plastic waste in the oceans has become a pressing issue. •Here we review the susceptibility of marine invertebrates to microplastic uptake. •Size, shape and abundance influence uptake; microfibres are considered most harmful. •Colonisation of microplastics could have population-level impacts. •Results will inform future marine litter research and management strategies. -- Here we review microplastic uptake in marine organisms and assess individual, population and community level effects, highlighting the most susceptible species

Effects of dredged sediment disposal on the coastal marine macrobenthic assemblage in Southern Brazil

Directory of Open Access Journals (Sweden)

L. G. Angonesi

Full Text Available The aim of this study was to evaluate the deposition impact of dredged material from Patos lagoon estuary on a benthic macroinvertebrate assemblage structure in an adjacent coastal marine area. Nine sampling stations were chosen at random in the disposal area, and nine others in the same way in an adjacent control area. Samples were collected at a 19 m depth before sediment disposal (11 July 2000, during dredging and disposal operations (25 Oct. 2000, and three months thereafter (24 Aug. 2001. Statistical analysis indicated that sampling periods presented similar characteristics in both the control and disposal sites. Disposal of dredged sediment from Patos lagoon had no detectable detrimental effects upon macrobenthic faunal assemblage at the dumping site. This result is attributed both to adaptation of resident biota to dynamic sedimentary conditions and to the fine estuarine sediment dredged, the dispersion of which in the water column might have minimized sediment deposition and consequent damage to the benthic fauna.

The impact of phosphate loading activities on near marine environment: The Syrian coast

International Nuclear Information System (INIS)

Al-Masri, M. S.; Mamish, S.; Budeir, Y.

2002-01-01

The impact of loading cargoes of phosphate ore into ships on the near marine environment at the Syrian coast has been evaluated. Results have shown a significant enhancement of 210 Po, 210 Pb and other natural radionuclides in sediment and surface water inside the port area. The highest 210 Po and 210 Pb concentrations observed in sediment were found to be 170 Bq kg -1 respectively, while 210 Po concentrations in surface water ranged from 5 to 20 mBql -1 . In addition, comparable values of 210 Po and 210 Pb for all marine organisms (algae, crab and fish) suggest that their use as indicators for phosphate pollution is not recommended. However, the effect of loading cargoes on Tartous port marine environment of Tartous was found to be mainly related to wind direction where radioactive air particulate are either being dispersed to land or sea. (author)

Global diffusive fluxes of methane in marine sediments

NARCIS (Netherlands)

Egger, M.; Riedinger, N.; Mogollón, J.M.; Jørgensen, B.B.

2018-01-01

Anaerobic oxidation of methane provides a globally important, yet poorly constrained barrier for the vast amounts of methane produced in the subseafloor. Here we provide a global map and budget of the methane flux and degradation in diffusion-controlled marine sediments in relation to the depth of

Diversity, Persistence and Evolution in Marine Sediments

DEFF Research Database (Denmark)

Starnawski, Piotr

2016-01-01

on the marine sediments communities was reviewed, it became apparent that there are some global trends in these populations ob- served in deep and shallow, organic rich and poor sediments. We have observed the same, often uncultured, organisms with very similar relative abundance profiles in reviewed sites...... communities as they transition from actively growing surface populations to barely dividing subsurface ones; (ii) evolutionary consequences of the prolonged residence in such environments and (iii) inferring function of the dominant groups found in deep sediments. When the current state of our knowledge....... In order to better understand this pattern we’ve reviewed the assembly processes that may lead to such situations, keeping in mind the limitations imposed by the environment.We’ve concluded, that due to low energy fluxes, and consequently low number of pos- sible cell divisions, selective survival of pre...

Absorption of sediment-bound radionuclides through the digestive tract of marine demersal fishes

International Nuclear Information System (INIS)

Koyanagi, Taku; Nakahara, Motokazu; Iimura, Mitsue

1978-01-01

Retention of 54 Mn, 59 Fe, 60 Co and 65 Zn by marine demersal fish, Ishigarei (Kareius bicoloratus) was observed by administering sediment-bound radioisotopes orally to the fishes to elucidate the contribution of sediment to the accumulation of radionuclides by marine benthic organisms. The sediment had high distribution coefficients for these radionuclides and from the result of leaching experiments with acidified seawater, considerable fractions of radioactive Mn, Co and Zn in the sediment were assumed to be leached in the stomach of the fishes. Retention patterns of the nuclides in the whole-body of the fishes were analyzed by peeling off method and two components were obtained for all the nuclides. The parameters which characterized the retention patterns suggested relatively high absorption efficiencies of the radionuclides except 59 Fe through the digestive tract of the fishes and the retention patterns of the slower component were supposed to be similar to those observed for the nuclides taken up from seawater or food by the dishes. Rapid and higher transfer of the absorbed radionuclides to the particular organs of the fishes suggested the important role of the sediment in the radioactive contamination of marine demersal fishes. (author)

Including impacts of particulate emissions on marine ecosystems in life cycle assessment: the case of offshore oil and gas production.

Science.gov (United States)

Veltman, Karin; Huijbregts, Mark A J; Rye, Henrik; Hertwich, Edgar G

2011-10-01

Life cycle assessment is increasingly used to assess the environmental performance of fossil energy systems. Two of the dominant emissions of offshore oil and gas production to the marine environment are the discharge of produced water and drilling waste. Although environmental impacts of produced water are predominantly due to chemical stressors, a major concern regarding drilling waste discharge is the potential physical impact due to particles. At present, impact indicators for particulate emissions are not yet available in life cycle assessment. Here, we develop characterization factors for 2 distinct impacts of particulate emissions: an increased turbidity zone in the water column and physical burial of benthic communities. The characterization factor for turbidity is developed analogous to characterization factors for toxic impacts, and ranges from 1.4 PAF (potentially affected fraction) · m(3) /d/kg(p) (kilogram particulate) to 7.0 x 10³ [corrected] for drilling mud particles discharged from the rig. The characterization factor for burial describes the volume of sediment that is impacted by particle deposition on the seafloor and equals 2.0 × 10(-1) PAF · m(3) /d/kg(p) for cutting particles. This characterization factor is quantified on the basis of initial deposition layer characteristics, such as height and surface area, the initial benthic response, and the recovery rate. We assessed the relevance of including particulate emissions in an impact assessment of offshore oil and gas production. Accordingly, the total impact on the water column and on the sediment was quantified based on emission data of produced water and drilling waste for all oil and gas fields on the Norwegian continental shelf in 2008. Our results show that cutting particles contribute substantially to the total impact of offshore oil and gas production on marine sediments, with a relative contribution of 55% and 31% on the regional and global scale, respectively. In contrast, the

Global distribution of radiolytic H2 production in marine sediment and implications for subsurface life

Science.gov (United States)

Sauvage, J.; Flinders, A. F.; Spivack, A. J.; D'Hondt, S.

2017-12-01

We present the first global estimate of radiolytic H2production in marine sediment. Knowledge of microbial electron donor production rates is critical to understand the bioenergetics of Earth's subsurface ecosystems In marine sediment, radiolysis of water by radiation from naturally occurring radionuclides leads to production of reduced (H2) and oxidized (H2O2, O2) species. Water radiolysis is catalyzed by marine sediment. The magnitude of catalysis depends on sediment composition and radiation type. Deep-sea clay is especially effective at enhancing H2 yields, increasing yield by more than an order of magnitude relative to pure water. This previously unrecognized catalytic effect of geological materials on radiolytic H2 production is important for fueling microbial life in the subseafloor, especially in sediment with high catalytic power. Our estimate of radiolytic H2 production is based on spatially integrating a previously published model and uses (i) experimentally constrained radiolytic H2 yields for the principal marine sediment types, (ii) bulk sediment radioactive element content of sediment cores in three ocean basins (N. Atlantic, N. and S. Pacific), and global distributions of (iii) seafloor lithology, (iv) sediment porosity, and (v) sediment thickness. We calculate that global radiolytic H2 production in marine sediment is 1.6E+12 mol H2 yr-1. This production rate is small relative to the annual rate of photosynthetic organic-matter production in the surface ocean. The globally integrated ratio of radiolytic H2 production relative to photosynthetic primary production is 4.1E-4, based on electron equivalences. Although small relative to global photosynthetic biomass production, sediment-catalyzed production of radiolytic products is significant in the subseafloor. Our analysis of 9 sites in the N. Atlantic, N. and S. Pacific suggests that H2 is the primary microbial fuel in organic-poor sediment older than a few million years; at these sites, calculated

Energy Gradients Structure Microbial Communities Across Sediment Horizons in Deep Marine Sediments of the South China Sea

Science.gov (United States)

Graw, Michael F.; D'Angelo, Grace; Borchers, Matthew; Thurber, Andrew R.; Johnson, Joel E.; Zhang, Chuanlun; Liu, Haodong; Colwell, Frederick S.

2018-01-01

The deep marine subsurface is a heterogeneous environment in which the assembly of microbial communities is thought to be controlled by a combination of organic matter deposition, electron acceptor availability, and sedimentology. However, the relative importance of these factors in structuring microbial communities in marine sediments remains unclear. The South China Sea (SCS) experiences significant variability in sedimentation across the basin and features discrete changes in sedimentology as a result of episodic deposition of turbidites and volcanic ashes within lithogenic clays and siliceous or calcareous ooze deposits throughout the basin's history. Deep subsurface microbial communities were recently sampled by the International Ocean Discovery Program (IODP) at three locations in the SCS with sedimentation rates of 5, 12, and 20 cm per thousand years. Here, we used Illumina sequencing of the 16S ribosomal RNA gene to characterize deep subsurface microbial communities from distinct sediment types at these sites. Communities across all sites were dominated by several poorly characterized taxa implicated in organic matter degradation, including Atribacteria, Dehalococcoidia, and Aerophobetes. Sulfate-reducing bacteria comprised only 4% of the community across sulfate-bearing sediments from multiple cores and did not change in abundance in sediments from the methanogenic zone at the site with the lowest sedimentation rate. Microbial communities were significantly structured by sediment age and the availability of sulfate as an electron acceptor in pore waters. However, microbial communities demonstrated no partitioning based on the sediment type they inhabited. These results indicate that microbial communities in the SCS are structured by the availability of electron donors and acceptors rather than sedimentological characteristics. PMID:29696012

Linking metatranscriptomic to bioremediation processes of oil contaminated marine sediments

Science.gov (United States)

Cuny, P.; Atkinson, A.; Léa, S.; Guasco, S.; Jezequel, R.; Armougom, F.; Michotey, V.; Bonin, P.; Militon, C.

2016-02-01

Oil-derived hydrocarbons are one major source of pollution of marine ecosystems. In coastal marine areas they tend to accumulate in the sediment where they can impact the benthic communities. Oil hydrocarbons biodegradation by microorganisms is known to be one of the prevalent processes acting in the removal of these contaminants from sediments. The redox oscillation regimes generated by bioturbation, and the efficiency of metabolic coupling between functional groups associated to these specific redox regimes, are probably determinant factors controlling hydrocarbon biodegradation. Metatranscriptomic analysis appears like a promising approach to shed new light on the metabolic processes involved in the response of microbial communities to oil contamination in such oxic/anoxic oscillating environments. In the framework of the DECAPAGE project (ANR CESA-2011-006 01), funded by the French National Agency for Research, the metatranscriptomes (RNA-seq) of oil contaminated or not (Ural blend crude oil, 5 000 ppm) and bioturbated or not (addition of the common burrowing organism Hediste diversicolor, 1000 ind/m2) mudflat sediments, incubated in microcosms during 4 months at 19±1°C, were compared. The analysis of active microbial communities by SSU rRNA barcoding shows that the main observable changes are due to the presence of H. diversicolor. On the contrary, oil addition is the main factor explaining the observed changes in the genes expression patterns with 1949 genes specifically up or down-regulated (which is the case of only 245 genes when only H. diversicolor worms are added). In particular, the oil contamination leads to a marked overexpression (i) of benzyl- and alkylsuccinate synthase genes (ass and bss) that are involved in the anaerobic metabolism of aromatics (toluene) and alkanes, respectively and, (ii) of genes coding for nucleotide excision repair exonucleases indicating that DNA repair processes are also activated.

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...

Solidification/stabilization of dredged marine sediments for road construction.

Science.gov (United States)

Wang, Dong Xing; Abriak, Nor Edine; Zentar, Rachid; Xu, WeiYa

2012-01-01

Cement/lime-based solidification is an environmentally sound solution for the management of dredged marine sediments, instead of traditional solutions such as immersion. Based on the mineralogical composition and physical characteristics of Dunkirk sediments, the effects of cement and lime are assessed through Atterberg limits, modified Proctor compaction, unconfined compressive strength and indirect tensile strength tests. The variation of Atterberg limits and the improvement in strength are discussed at different binder contents. The potential of sediments solidified with cement or lime for road construction is evaluated through a proposed methodology from two aspects: I-CBR value and material classification. The test results show the feasibility of solidified dredged sediments for beneficial use as a material in road construction. Cement is superior to lime in terms of strength improvement, and adding 6% cement is an economic and reasonable method to stabilize fine sediments.

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

DEFF Research Database (Denmark)

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

and promotes the formation of Mg-calcite and iron oxides in the oxic zone. Oxygen seems to be the major electron acceptor, and more than 40% of the oxygen consumption in sediments can be driven by long distance electron transfer from distant electron donors. The major e-donor is sulfide, which is oxidized......Anaerobic oxidation of organic matter in marine sediment is traditionally considered to be coupled to oxygen reduction via a cascade of redox processes and transport of intermittent electron donors and acceptors. Electric currents have been found to shortcut this cascade and directly couple...... 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...

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.

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...

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.

Sediment Contaminants and Infauna Associated with Recreational Boating Structures in a Multi-Use Marine Park

Science.gov (United States)

Sim, Vivian X. Y.; Dafforn, Katherine A.; Simpson, Stuart L.; Kelaher, Brendan P.; Johnston, Emma L.

2015-01-01

Multi-use marine parks achieve conservation through spatial management of activities. Zoning of marine parks in New South Wales, Australia, includes high conservation areas and special purpose zones (SPZ) where maritime activities are concentrated. Although such measures geographically constrain anthropogenic impacts, we have limited understanding of potential ecological effects. We assessed sediment communities and contaminants adjacent to boating infrastructure (boat ramps, jetties and a marina) in a SPZ from the Clyde Estuary in Batemans Marine Park. Metal concentrations and fines content were elevated at boating structures compared to reference sites. Species richness was higher at sites with boating structures, where capitellid polychaetes and nematodes dominated the communities. Changes associated with boating structures were localised and did not extend beyond breakwalls or to reference sites outside the SPZ. The study highlights the benefits of appropriate zoning in a multi-use marine park and the potential to minimise stress on pristine areas through the application of spatial management. PMID:26086427

Sediment Contaminants and Infauna Associated with Recreational Boating Structures in a Multi-Use Marine Park.

Science.gov (United States)

Sim, Vivian X Y; Dafforn, Katherine A; Simpson, Stuart L; Kelaher, Brendan P; Johnston, Emma L

2015-01-01

Multi-use marine parks achieve conservation through spatial management of activities. Zoning of marine parks in New South Wales, Australia, includes high conservation areas and special purpose zones (SPZ) where maritime activities are concentrated. Although such measures geographically constrain anthropogenic impacts, we have limited understanding of potential ecological effects. We assessed sediment communities and contaminants adjacent to boating infrastructure (boat ramps, jetties and a marina) in a SPZ from the Clyde Estuary in Batemans Marine Park. Metal concentrations and fines content were elevated at boating structures compared to reference sites. Species richness was higher at sites with boating structures, where capitellid polychaetes and nematodes dominated the communities. Changes associated with boating structures were localised and did not extend beyond breakwalls or to reference sites outside the SPZ. The study highlights the benefits of appropriate zoning in a multi-use marine park and the potential to minimise stress on pristine areas through the application of spatial management.

Sediment Contaminants and Infauna Associated with Recreational Boating Structures in a Multi-Use Marine Park.

Directory of Open Access Journals (Sweden)

Vivian X Y Sim

Full Text Available Multi-use marine parks achieve conservation through spatial management of activities. Zoning of marine parks in New South Wales, Australia, includes high conservation areas and special purpose zones (SPZ where maritime activities are concentrated. Although such measures geographically constrain anthropogenic impacts, we have limited understanding of potential ecological effects. We assessed sediment communities and contaminants adjacent to boating infrastructure (boat ramps, jetties and a marina in a SPZ from the Clyde Estuary in Batemans Marine Park. Metal concentrations and fines content were elevated at boating structures compared to reference sites. Species richness was higher at sites with boating structures, where capitellid polychaetes and nematodes dominated the communities. Changes associated with boating structures were localised and did not extend beyond breakwalls or to reference sites outside the SPZ. The study highlights the benefits of appropriate zoning in a multi-use marine park and the potential to minimise stress on pristine areas through the application of spatial management.

Marinicella sediminis sp. nov., isolated from marine sediment

Science.gov (United States)

A novel heterotrophic, Gram-stain-negative, aerobic, rod-shaped, pale yellow, non-motile and non-spore-forming bacterium, designated as strain F2**T, was isolated from the marine sediment collected from Weihai coastal, Shandong Province, PR China. Optimal growth occurred at 33 °C (range 10–37 °C), w...

A COMPARISON OF MAJOR ELEMENTS BETWEEN MARINE SEDIMENTS AND IGNEOUS ROCKS: AS A BASIC DETERMINATION OF THE SEDIMENT SOURCE AT UJUNG PENYUSUK WATERS, NORTH BANGKA,BANGKA BELITUNG PROVINCE

Directory of Open Access Journals (Sweden)

Ediar Usman

2017-07-01

Full Text Available Three igneous rock samples from the coast and five sediments from the marine of Ujung Penyusuk Waters have been used for chemistry analysis as the basic determination of sediment source. The result of chemistry analysis shows that the major element with relatively same pattern. In the igneous rock samples, the result of chemistry analysis shows the SiO2 ranges between 72.3 - 76.8%, Al2O3 (9.64 - 11.64%, and Fe2O3 ( 2.08 - 2.18%. In the marine sediment, the content of SiO2 is between 62.2 and 66.5%, Al2O3 (2.93 - 3.63% and Fe2O3 (21.19 - 24.40%. Other elements such as CaO, MgO, K2O, Na2O and TiO2 are relatively similar values in all samples. The difference of element content in marine sediment and coastal igneous rock occurs in Al2O3 and Fe2O3. The Al2O3 is small in marine sediment while the Fe2O3 is higher compared to igneous rocks. Decreasing of the Al2O3 (kaolinite in the marine sediment is caused by the character of the Al2O3 that was derived from quartz rich of igneous rocks forming kaolinite. It was than deposited in the sea floor. Increasing of the Fe2O3 in marine sediment is caused by addition reaction of the Fe from the sea. Generally, the content of the SiO2 (quartz in igneous rock and marine sediment belongs to the same group source that is acid igneous rock. The SiO2 in the sediment belongs to a group of granitoid.

Energy Gradients Structure Microbial Communities Across Sediment Horizons in Deep Marine Sediments of the South China Sea

Directory of Open Access Journals (Sweden)

Michael F. Graw

2018-04-01

Full Text Available The deep marine subsurface is a heterogeneous environment in which the assembly of microbial communities is thought to be controlled by a combination of organic matter deposition, electron acceptor availability, and sedimentology. However, the relative importance of these factors in structuring microbial communities in marine sediments remains unclear. The South China Sea (SCS experiences significant variability in sedimentation across the basin and features discrete changes in sedimentology as a result of episodic deposition of turbidites and volcanic ashes within lithogenic clays and siliceous or calcareous ooze deposits throughout the basin's history. Deep subsurface microbial communities were recently sampled by the International Ocean Discovery Program (IODP at three locations in the SCS with sedimentation rates of 5, 12, and 20 cm per thousand years. Here, we used Illumina sequencing of the 16S ribosomal RNA gene to characterize deep subsurface microbial communities from distinct sediment types at these sites. Communities across all sites were dominated by several poorly characterized taxa implicated in organic matter degradation, including Atribacteria, Dehalococcoidia, and Aerophobetes. Sulfate-reducing bacteria comprised only 4% of the community across sulfate-bearing sediments from multiple cores and did not change in abundance in sediments from the methanogenic zone at the site with the lowest sedimentation rate. Microbial communities were significantly structured by sediment age and the availability of sulfate as an electron acceptor in pore waters. However, microbial communities demonstrated no partitioning based on the sediment type they inhabited. These results indicate that microbial communities in the SCS are structured by the availability of electron donors and acceptors rather than sedimentological characteristics.

Phosphorus cycling and burial in sediments of a seasonally hypoxic marine basin

NARCIS (Netherlands)

Sulu-Gambari, F; Hagens, M.; Behrends, T; Seitaj, D.; Meysman, F.J.R.; Middelburg, J.; Slomp, C.P.

2018-01-01

Recycling of phosphorus (P) from sediments contributes to the development of bottom-water hypoxia in many coastal systems. Here, we present results of a year-long assessment of P dynamics in sediments of a seasonally hypoxic coastal marine basin (Lake Grevelingen, the Netherlands) in 2012.

Biomarkers and their stable isotopes in Cenozoic sediments above the Chicxulub impact crater

Science.gov (United States)

Grice, K.; Schaefer, B.; Coolen, M.; Greenwood, P. F.; Scarlett, A. G.; Freeman, K.; Lyons, S. L.

2017-12-01

The most widely accepted hypothesis for the cause of the End-Cretaceous mass extinction (K/Pg event) 66 Ma ago is the impact of an extra-terrestrial body, which produced the 200 km wide Chicxulub impact structure. This event led to an extinction of 75% of all species on Earth. The massive extinction in the terrestrial realm is partly attributed to the intense heat pulse, the widespread wild fires caused by the impact and the ensuing darkness, as dust and sulfate aerosols blocked out the sun leading to photosynthesis shut off and productivity collapse in both the terrestrial and marine realms. The marine realm may additionally have experienced ocean acidification resulting in mass extinction of plankton (foraminifera and coccolithophorids) and marine reptiles. Samples from the Cenozoic marine sediments including the Paleocene-Eocene Thermal Maximum (PETM) have been extracted for hydrocarbons and analysed to investigate the molecular and isotopic organic record of biotic and environmental change after the K/Pg boundary event. Specific biomarker-precursor relationship has been established by the direct correlation of sedimentary biomarkers with the biochemicals (e.g. lipids) of extant biological systems. The structural characterisation of biomarkers as well as their stable isotopic compositions (C, H and N) are used to evaluate the source(s) of organic matter (OM) and to reconstruct paleoenvironmental depositional conditions. Throughout the Cenozoic sediments (including the PETM) the biomarker distribution suggests a variation in the source of organic matter from terrestrial to marine. Furthermore, the presence of sulfurised biomarkers indicates euxinic environmental conditions at the time of deposition. Biomarker distributions indicative of green sulfur bacteria reveal persistent photic zone euxinic conditions at several intervals in the Cenozoic. Further compound specific isotope analyses will provide insights into the long-term biogeochemical cycling of C, H and S

Radiological assessment of coastal marine sediment and water samples, Karachi coast, Pakistan

International Nuclear Information System (INIS)

Qureshi, R.M.; Mashiatullah, A.; Akram, M.; Sajjad, M.I.; Shafiq, M.; Javed, T.; Aslam, M.

1999-04-01

Concentrations of selective natural radionuclides (/sup 226/Ra, /sup 228/Ra, /sup 40/K) in shallow marine coastal sediments and sea water off Karachi coast, Pakistan, were measured with a hyper pure germanium (HPGe) gamma spectrometer. Sediment and water samples were collected from polluted Layari and Malire River downstream (pre-out fall), Gizri Creek, Layari River out fall in Karachi harbor, Karachi Harbor/ Manora Channel Mains, as well as from open sea (South-East Coast and North-West Coast) within the 10m depth contour. No artificial radionuclides (e.g. /sup 60/Co, /sup 137/Cs and /sup 134/Cs were detected in both water and sediment samples at any of these locations. The activity of /sup 226/Ra in coastal river sediments is found below its limit of detection (<18.35 Bqkg/sup -1/). Activity of /sup 228/Ra in sediments off Karachi Coast ranges between 11.80 +- 3.60 to 37.27+- 4.31 Bqkg/sup -1/. The highest activity was found south of Nuclear Power Station (KANUPP) and the lowest activity was found in the vicinity of Oyster Rocks (open sea). The /sup 226/Ra activity ranges from 19.40+- 5.88 to 67.14 +- 10.02 Bqkg/sup -1/. The activity of /sup 228/Ra in sediments of Manora Channel, South-east Coast of Karachi and the North west coast of Karachi are also in agreement with the IAEA marine sediment standard namely: IAEA-135 (/sup 228/Ra = 36.7 +- 3 Bqkg/sup -1/). The activity of /sup 226/Ra for the South East Coast of Karachi and the North west coast of Karachi are also in agreement with the IAEA marine sediment standard namely: IAEA 135(/sup 226/Ra=23.9 +- 1.1 Bqkg/sup -1/) and Pacific Ocean sediment standard namely: IAEA-368 (/sup 226/Ra=21.4+- 1.1 Bqkg/sup -1/). The /sup 40/K activity in sea sediments varies from 197.7+- 44.24 to 941.90 +- 39.00 Bqkg-1). The highest activity is observed in the vicinity of Oyster Rocks (open sea) along the Clifton coast (South-East Cost of Karachi) and the lowest activity is found south of Nuclear Power Station (KANUPP) along the

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

International Nuclear Information System (INIS)

Organo, Catherine

1997-01-01

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 234 U/2 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 234 U/ 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

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

International Nuclear Information System (INIS)

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

2006-01-01

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

Plutonium behavior during the early diagenesis of marine sediments: applications to two marine environments labelled by radionuclides released from reprocessing plants

International Nuclear Information System (INIS)

Gouzy, A.

2004-12-01

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)

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

A statistical approach to the interpretation of aliphatic hydrocarbon distributions in marine sediments

Science.gov (United States)

Rapp, J.B.

1991-01-01

Q-mode factor analysis was used to quantitate the distribution of the major aliphatic hydrocarbon (n-alkanes, pristane, phytane) systems in sediments from a variety of marine environments. The compositions of the pure end members of the systems were obtained from factor scores and the distribution of the systems within each sample was obtained from factor loadings. All the data, from the diverse environments sampled (estuarine (San Francisco Bay), fresh-water (San Francisco Peninsula), polar-marine (Antarctica) and geothermal-marine (Gorda Ridge) sediments), were reduced to three major systems: a terrestrial system (mostly high molecular weight aliphatics with odd-numbered-carbon predominance), a mature system (mostly low molecular weight aliphatics without predominance) and a system containing mostly high molecular weight aliphatics with even-numbered-carbon predominance. With this statistical approach, it is possible to assign the percentage contribution from various sources to the observed distribution of aliphatic hydrocarbons in each sediment sample. ?? 1991.

The onset of fabric development in deep marine sediments

NARCIS (Netherlands)

Maffione, Marco; Morris, Antony

2017-01-01

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

Effect of Suez Canal Marine Sediment on Sorption of Cesium

International Nuclear Information System (INIS)

Hassan, H.B.

2016-01-01

Suez Canal is surrounded by navigation, industrial, agricultural activities and suffers from high rate of population growth that discharging waste into Suez Canal. The Suez Canal coastal waters are influenced by a complex variety of physical, geochemical and biological processes, which influence the behavior, transport and fate of containments released into the marine environment. Sorption of releasing containment such as cesium in Suez Canal water is investigated because of its toxic effect on the marine environment. The object of present study is to determine the effects some of physical and chemical characteristics of collected sediment samples from the three important locations on Suez Canal (Suez Bay, Bitter Lakes and El- Temsah Lake beaches) on sorption behavior of cesium by using batch experiment. Batch experiment was used to study the sorption of the cesium ion. The sorption process is dependent on mineral constituents of Suez Canal sediment and their characteristics. Analytical methods which included particle size and X-ray diffraction (XRD) analyses found that particle size of Suez Canal sediment samples is characterized by sand to fine sand and quartz is the main mineralogical species. Distribution coefficient (K d ) which represent geochemical processes and particle size of these sediment samples effect on the degree of cesium sorption to the sediment. Also (K d ) increase with increase cation exchangeable capacity (CEC). The Suez Canal sediment samples have low (K d ) values which effected by their physical and chemical properties. Sample (2) has highest distribution coefficient (K d ) between measured samples due to containing ratio 30% of fine sand and high ratio of organic matter.

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

International Nuclear Information System (INIS)

2016-01-01

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

Hydrocarbon-degrading sulfate-reducing bacteria in marine hydrocarbon seep sediments

OpenAIRE

Kleindienst, Sara

2012-01-01

Microorganisms are key players in our biosphere because of their ability to degrade various organic compounds including a wide range of hydrocarbons. At marine hydrocarbon seeps, more than 90% of sulfate reduction (SR) is potentially coupled to non-methane hydrocarbon oxidation. Several hydrocarbon-degrading sulfate-reducing bacteria (SRB) were enriched or isolated from marine sediments. However, in situ active SRB remained largely unknown. In the present thesis, the global distribution and a...

Determination of multi-element in marine sediment samples collected in Angola by the k0-NAA technique

International Nuclear Information System (INIS)

Teixeira, M.C.P.; Ho Manh Dung; Cao Dong Vu; Nguyen Thi Sy; Nguyen Thanh Binh; Vuong Huu Tan

2006-01-01

The marine sediment samples were designed to collect in Angola for marine environmental pollution study. The k 0 -standardization method of neutron activation analysis (k 0 -NAA) on Dalat research reactor has been developed to determine of multi-element in the Angola marine sediment samples. The samples were irradiated in cell 7-1 for short- and middle-lived nuclides and rotary specimen rack for long-lived nuclides. The irradiation facilities were characterized for neutron spectrum parameters and post-activated samples were measured on the calibrated gamma-ray spectrometers using HPGe detectors. The analytical results for 9 marine sediment samples with 27 elements: Al, As, Br, Ca, Ce,Cl, Co, Cs, Dy, Fe, Hf, I, K, Mg, Mn, Na, Rb, Sb, Sc, Se, Sm, Th, Ti, U, V and Zn in term of mean concentration, standard deviation and their content range are shown in the report. The analytical quality assurance was done by analysis of a Japan's certified reference material namely marine sediment NMIJ-CRM-7302a. These preliminary results revealed that the k 0 -NAA technique on the Dalat research reactor is a good analytical technique for determination of multi-element in the marine sediment samples. Some heavy metals and trace elements determined in this work possibly connected to the human activities at the sampling region. (author)

Mechanical response of marine sediments resulting from isolation of radioactive wastes

International Nuclear Information System (INIS)

Dawson, P.R.

1979-01-01

Preliminary analyses of canister movement rsulting from thermally induced density gradients have been performed using a creeping viscoplastic flow model in conjunction with a creep equation evaluated from literature data for fine-grained clay. The stress levels predicted are quite low relative to the sediment quasi-static strength indicating that creep testing of marine sediments at very low stress is necessary. 4 figures

Distribution of uranium in marine sediments

International Nuclear Information System (INIS)

Ordonez R, E.; Ramirez T, J.J.; Lopez M, J.; Aspiazu, J.; Ruiz F, A.C.; Valero C, N.

2008-01-01

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 234 U/ 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)

Algal and archaeal polyisoprenoids in a recent marine sediment

DEFF Research Database (Denmark)

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

2001-01-01

Analyses of C-13 contents of individual organic molecules in a marine sediment show that crocetane, 2,6,11,15-tetramethylhexadecane, an isomer of phytane, is produced by microorganisms that use methane as their main source of carbon. The sediments lie at a water depth of 68 m in the Kattegat......, the strait between Denmark and Sweden. Crocetane appears first 185 cm below the sediment-water interface, in the zone marking the transition from sulfate reduction to methanogenesis. Its delta C-13 value is -90 +/- 10 parts per thousand versus Vienna Pee Dee Belemnite (VPDB). Its structure, which includes......-consuming member of the microbial consortium responsible for the anaerobic oxidation of methane [Hoehler et al., 1994], in which, as first demonstrated quantitatively in these sediments [Iversen and Jorgensen, 1985], electrons are transferred from methane to sulfate. The presence of archaeal biomass throughout...

Degradation of Herbicides in the Tropical Marine Environment: Influence of Light and Sediment.

Science.gov (United States)

Mercurio, Philip; Mueller, Jochen F; Eaglesham, Geoff; O'Brien, Jake; Flores, Florita; Negri, Andrew P

2016-01-01

Widespread contamination of nearshore marine systems, including the Great Barrier Reef (GBR) lagoon, with agricultural herbicides has long been recognised. The fate of these contaminants in the marine environment is poorly understood but the detection of photosystem II (PSII) herbicides in the GBR year-round suggests very slow degradation rates. Here, we evaluated the persistence of a range of commonly detected herbicides in marine water under field-relevant concentrations and conditions. Twelve-month degradation experiments were conducted in large open tanks, under different light scenarios and in the presence and absence of natural sediments. All PSII herbicides were persistent under control conditions (dark, no sediments) with half-lives of 300 d for atrazine, 499 d diuron, 1994 d hexazinone, 1766 d tebuthiuron, while the non-PSII herbicides were less persistent at 147 d for metolachlor and 59 d for 2,4-D. The degradation of herbicides was 2-10 fold more rapid in the presence of a diurnal light cycle and coastal sediments; apart from 2,4-D which degraded more slowly in the presence of light. Despite the more rapid degradation observed for most herbicides in the presence of light and sediments, the half-lives remained > 100 d for the PS II herbicides. The effects of light and sediments on herbicide persistence were likely due to their influence on microbial community composition and its ability to utilise the herbicides as a carbon source. These results help explain the year-round presence of PSII herbicides in marine systems, including the GBR, but more research on the transport, degradation and toxicity on a wider range of pesticides and their transformation products is needed to improve their regulation in sensitive environments.

Transformation of PBDE mixtures during sediment transport and resuspension in marine environments (Gulf of Lion, NW Mediterranean Sea)

International Nuclear Information System (INIS)

Salvadó, Joan A.; Grimalt, Joan O.; López, Jordi F.; Durrieu de Madron, Xavier; Heussner, Serge; Canals, Miquel

2012-01-01

Polybromodiphenyl ethers (PBDEs) in superficial sediments from the Gulf of Lion were studied. They were largely predominated by BDE 209 (98.7% of all PBDEs) indicating that the main source of these pollutants was the commercial mixture deca-BDE. This compound and the less brominated BDE exhibited a southwestward decreasing concentration gradient following the dominant marine currents and bottom relief, e.g. the Mud Belt, the submarine canyons and the Open Continental Slope. All PBDEs exhibited statistically significant correlations confirming the common origin. However, a progressive transformation of the dumped BDE 209 was identified showing a depletion paralleled by increases of the less brominated BDEs (from 8.6% to 22%). These less brominated compounds were accumulated at about 100–140 km away from the Rhone prodelta, e.g. at the end of the submarine canyons, evidencing that these transformation compounds can be accumulated at long distances from the dumping sites in the marine system. Highlights: ► Polybromodiphenyl ethers are associated to organic carbon in marine sediments. ► PBDEs in marine sediments can accumulate further away than 140 km from the spill site. ► BDE-209 in marine sediments generate congeners found in banned commercial mixtures. ► BDE-209 in marine sediments generates new congeners not found in commercial mixtures. ► Submarine canyons channel PBDEs from the continental platform to the deep shelf. - Decomposition of decabromodiphenyl ether in marine sediments generates congeners found in banned mixtures in areas located far away from the discharge sites.

Constraints on the sources of branched tetraether membrane lipids in distal marine sediments

NARCIS (Netherlands)

Weijers, J.W.H.; Schefuß, E.; Kim, J.-H.; Sinninghe Damsté, J.; Schouten, S.

2014-01-01

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are membrane lipids produced by soil bacteria and occur in near coastal marine sediments as a result of soil organic matter input. Their abundance relative to marine-derived crenarchaeol, quantified in the BIT index, generally decreases

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)

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.

Investigation into spore coat properties for the rapid identification of endospores in marine sediments

Science.gov (United States)

Rattray, J. E.; Chakraborty, A.; Bernard, B. B.; Brooks, J.; Hubert, C. R.

2017-12-01

Understanding the sediment biogeography of dormant marine thermophilic bacterial endospores (thermospores) has the potential to assist locating and characterising working petroleum systems. The presence of thermospores in cold ocean environments suggests that distribution occurs via hydrocarbon seepage from thermally active reservoirs. Low abundance and endospore coat physiology mean nucleic acid based techniques have limited success for in situ detection of thermospores. Alternative rapid analytical methods are needed so we investigated using the Schaeffer-Fulton (malachite green and safranin) and DAPI (4',6-diamidino-2-phenylindole) staining techniques on thermospores from cultures and marine sediments. Sediment samples from 111 locations in the Eastern Gulf of Mexico (100 to 3300 m water depth; 6 to 600 km apart) were incubated at high temperature, followed by construction of 16S rRNA gene amplicon libraries (V3-V4 region; Illumina MiSeq) revealing enrichment of species-level thermospore OTUs. A sulfate reducing bacterium from site EGM080 was purified and classified based on its rRNA gene sequence as Desulfotomaculum geothermicum. Prior to thermospore staining the culture was kept in the death/ decline phase for 16 weeks to promote sporulation. Samples of D. geothermicum and the source marine sediment were fixed, stained then analysed using brightfield, phase contrast or fluorescence microscopy. Thermospores in pure culture were identified using phase contrast but were difficult to observe in the sediment sample due to particle aggregation. The Schaeffer-Fulton technique aided thermospore identification in a complex sediment sample matrix as thermospores were stained bright green, and also revealed that there were only spores and no (red stained) vegetative cells in the culture. Treatment with DAPI gave dull fluorescing cells but also provided insight into the behaviour of thermospores in sediment suspensions. Spores in the culture medium were free floating but

Assessment of Measurement Uncertainty Values of the Scandium Determination in Marine Sediment

International Nuclear Information System (INIS)

Rina-Mulyaningsih, Th.

2005-01-01

The result value of testing is meaningless if it isn't completed with uncertainty value. So that with the analysis result Sc in the marine sediment sample. It was assessed the uncertainty measurement of Sc analysis in marine sediment. The experiment was done in AAN Serpong laboratory. The result of calculation uncertainty on Sc analysis showed that the uncertainty components come from: preparation of sample and standard/comparator, purity of standard, counting statistics (sample and standard), repeatability, nuclear data and decay correction. The assessment on uncertainty must be done for the analysis of others elements, because each elements has difference nuclear and physical properties. (author)

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

International Nuclear Information System (INIS)

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

2012-01-01

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. - Highlights: ► Bioremediation performance was investigated on hydrocarbon contaminated sediments. ► Major changes in bacterial diversity and assemblage composition were observed. ► Temperature exerted the major effect on bacterial assemblages. ► High bacterial diversity increased significantly biodegradation performance. ► This should be considered for sediment remediation by bio-treatments. - Bioremediation strategies which can sustain high levels of bacterial diversity may significantly increase the biodegradation of hydrocarbons in contaminated marine sediments.

Petroleum hydrocarbon concentrations in marine sediments along Chennai Coast, Bay of Bengal, India.

Science.gov (United States)

Venkatachalapathy, R; Veerasingam, S; Ramkumar, T

2010-10-01

The spatial and temporal distribution of petroleum hydrocarbons (PHC) in marine sediments along the Chennai coast, Bay of Bengal was quantified by Ultra-Violet Fluorescence (UVF) Spectroscopy. The concentration of PHC in surface sediments varied from 1.88 to 39.76 ppm. The highest values obtained in the northern part of the study area, where shipping activities and land-based waste waters disposed into sea through the rivers like Kuvam and Adayar. The Adayar (7.26-16.83 ppm) and Kuvam (5.5-39.72 ppm) cores reveal a clear horizon of increase in PHC above 50 and 35 cm respectively. PHC values showed a decreasing pattern with depth in all sediment cores suggesting the excess anthropogenic loading occurring in the recent past. The present study revealed that the PHC values of Chennai coastal sediments are lower than the values reported from selected costal areas including the sediment of the Mumbai coast (7.6-42.8 ppm), Arabian Sea. The results will be useful for pollution monitoring program along the coastal region and also to check the level of petroleum hydrocarbons in marine sediments.

Trace Elements in Marine Sediment and Organisms in the Gulf of Thailand

Science.gov (United States)

Worakhunpiset, Suwalee

2018-01-01

This review summarizes the findings from studies of trace element levels in marine sediment and organisms in the Gulf of Thailand. Spatial and temporal variations in trace element concentrations were observed. Although trace element contamination levels were low, the increased urbanization and agricultural and industrial activities may adversely affect ecosystems and human health. The periodic monitoring of marine environments is recommended in order to minimize human health risks from the consumption of contaminated marine organisms. PMID:29677146

Redox-dependent phosphorus burial in modern and ancient marine sediments. Geologica Ultraiectina (334)

NARCIS (Netherlands)

Kraal, P.

2011-01-01

Phosphorus (P) is an essential nutrient in Earth’s biosphere that helps regulate marine primary productivity. Burial in sediments is the only pathway for long-term removal of P from the marine reservoir, the efficiency of which depends strongly on the redox state of the bottom waters;

Sediment-worm interaction: transfer of 65Zn from marine silt by the polychaete, Nereis diversicolor

International Nuclear Information System (INIS)

Renfro, W.C.; Benayoun, G.

1976-01-01

Marine polychaete worms (Nereis diversicolor) accumulated 65 Zn sorbed to silty marine sediment for 5 days and were then transferred to nonradioactive sediment in the laboratory and in the sea. The mean biological half-life (T/sub B//2/) for the laboratory worms did not differ greatly from that for worms in the sea. Worms living in small flowing seawater systems containing 16 cm 3 of sediment accumulated 65 Zn added to each system in the form of radioactive organic detritus. Higher percentage uptake of 65 Zn was from radioactive detritus particles 0.2 to 2 mm in diameter resting on the sediment surface or mixed with sediment than from finely-ground ( 65 Zn coprecipitated from fresh water with Fe(OH) 3 was accumulated by N. diversicolor when the precipitate was on the sediment surface than when the precipitate was well mixed with the sediment. These experimental results indicate that benthic organisms may take up limited amounts of heavy metals associated with bottom sediments and recycle them to benthic and pelagic food webs

Impact of redox-stratification on the diversity and distribution of bacterial communities in sandy reef sediments in a microcosm

Institute of Scientific and Technical Information of China (English)

GAO Zheng; WANG Xin; Angelos K. HANNIDES; Francis J. SANSONE; WANG Guangyi

2011-01-01

Relationships between microbial communities and geochemical environments are important in marine microbial ecology and biogeochemistry.Although biogeochemical redox stratification has been well documented in marine sediments,its impact on microbial communities remains largely unknown.In this study,we applied denaturing gradient gel electrophoresis (DGGE) and clone library construction to investigate the diversity and stratification of bacterial communities in redox-stratified sandy reef sediments in a microcosm.A total of 88 Operational Taxonomic Units (OTU) were identified from 16S rRNA clone libraries constructed from sandy reef sediments in a laboratory microcosm.They were members of nine phyla and three candidate divisions,including Proteobacteria (Alpha-,Beta-,Gamma-,Delta-,and Epsilonproteobacteria),Actinobacteria,Acidobacteria,Bacteroidetes,Chloroflexi,Cyanobacteria,Firmicutes,Verrucomicrobia,Spirochaetes,and the candidate divisions WS3,SO31 and AO19.The vast majority of these phylotypes are related to clone sequences from other marine sediments,but OTUs of Epsilonproteobacteria and WS3 are reported for the first time from permeable marine sediments.Several other OTUs are potential new bacterial phylotypes because of their low similarity with reference sequences.Results from the 16S rRNA,gene clone sequence analyses suggested that bacterial communities exhibit clear stratification across large redox gradients in these sediments,with the highest diversity found in the anoxic layer (15-25 mm) and the least diversity in the suboxic layer (3-5 mm).Analysis of the nosZ,and amoA gene libraries also indicated the stratification of denitrifiers and nitrifiers,with their highest diversity being in the anoxic and oxic sediment layers,respectively.These results indicated that redox-stratification can affect the distribution of bacterial communities in sandy reef sediments.

The geochemistry and mobility of the lanthanides in marine sediments

International Nuclear Information System (INIS)

Elderfield, H.

1988-07-01

A study has been made to evaluate lanthanide mobility in sediments directly by measuring concentrations of 10 lanthanide elements in sediments and pore waters. Due to the very low concentrations of the lanthanides in sea water relative to marine sediments, evidence of lanthanide mobilization is usually difficult to detect from studies of solid-phase geochemistry. Results show that the lanthanides can be extremely mobile. Concentrations in pore waters up to 100 times sea water concentrations have been measured. The conclusions are tentative but the present data suggest that the lanthanides are mobilized during oxidation of organic-rich sediments and are relocated in part in association with secondary Fe-rich phases. The behaviour of Ce is, predictably, somewhat different from the other lanthanides and may be more mobile as a consequence of its redox chemistry. (author)

Comparison of influences of sediments and sea water on accumulation of radionuclides by marine organisms

International Nuclear Information System (INIS)

Ueda, Taiji; Nakamura, Ryoichi; Suzuki, Yuzuru

1978-01-01

The concentration factors of 106 Ru- 106 Rh and 137 Cs for a marine bivalve and a alga were investigated. Furthermore, the transfer ratio ([cpm/g of organism]/[cpm/g of sediment]) of these nuclides from contaminated sediments to organisms was examined. Then the concentration factors were compared with the transfer ratio to know the relative influence of sea water and sediments on the contamination of marine organisms. The obtained figures, we call the biological factor of the sediments (BFS), were 70 and 160 for red alga and bivalve on 137 Cs, and 5400 and 2900 for them in case of 106 Ru- 106 Rh, respectively. These figures were comparable to those for annelid worm, 40 on 137 Cs and 1000 on 106 Ru- 106 Rh. (auth.)

The physical impacts of microplastics on marine organisms: a review.

Science.gov (United States)

Wright, Stephanie L; Thompson, Richard C; Galloway, Tamara S

2013-07-01

Plastic debris at the micro-, and potentially also the nano-scale, are widespread in the environment. Microplastics have accumulated in oceans and sediments worldwide in recent years, with maximum concentrations reaching 100 000 particles m(3). Due to their small size, microplastics may be ingested by low trophic fauna, with uncertain consequences for the health of the organism. This review focuses on marine invertebrates and their susceptibility to the physical impacts of microplastic uptake. Some of the main points discussed are (1) an evaluation of the factors contributing to the bioavailability of microplastics including size and density; (2) an assessment of the relative susceptibility of different feeding guilds; (3) an overview of the factors most likely to influence the physical impacts of microplastics such as accumulation and translocation; and (4) the trophic transfer of microplastics. These findings are important in guiding future marine litter research and management strategies. Copyright © 2013 Elsevier Ltd. All rights reserved.

Heavy metals in marine coastal sediments: assessing sources, fluxes, history and trends.

Science.gov (United States)

Frignani, Mauro; Bellucci, Luca Giorgio

2004-01-01

Examples are presented from the Adriatic Sea, the Ligurian Sea and the Venice Lagoon to illustrate different approaches to the study of anthropogenic metals in marine coastal sediments. These examples refer to studies of areal distribution and transport mechanisms, individuation of the sources, sediment dating, chronology of the fluxes, present and past trends. In particular, some of the findings achieved in studying the Venice Lagoon are discussed from the point of view of anthropogenic changes both in sediment composition and contaminant fluxes.

226Ra chronology of a coastal marine sediment

International Nuclear Information System (INIS)

Koide, M.; Bruland, K.; Goldberg, E.D.

1976-01-01

Unsupported 226 Ra (tsub (1/2) = 1620 years) in marine sediments can provide a basis for measuring rates of accumulation of the order of centimeters per thousand years. The excess radium apparently enters the sediments incorporated in phytoplankton. The sensitivity of the method depends upon the initial value of the unsupported 226 Ra and of the value of 230 Th, a parent of 226 Ra, in the sedimentary components. 226 Ra dating was applied to a sediment taken from the slope of the San Clemente Basin in the Southern California coastal region. Rates of sedimentation over two half-lives of the nuclide were found to be either 5.2 or 5.3 cm/1000 years depending upon which of two models for the geochronology is used. One model assumes that the 230 Th brings to the deposit an amount of 226 Ra in equilibrium with it. The other is based upon the growth of the 226 Ra from the 230 Th in the sedimentary components. 238+239 Pu and 210 Pb levels in the upper strata indicated sedimentation rates of the order of 100-500 cm/1000 years, i.e. much faster accumulations. It is suggested that these derived rates are spurious and reflect bioturbative activities of surface-living organisms. (Auth.)

Bacterial corrosion in marine sediments: influence of cathodic protection

International Nuclear Information System (INIS)

Therene, Martine

1988-01-01

In order to protect offshore structures from marine corrosion, cathodic protection is widely applied via sacrificial anodes (for example zinc or aluminium) or impressed current. In aerated seawater, steel is considered to be protected when a potential of -8050 mV/Cu.CuSO 4 is achieved. In many cases, however this potential must be lowered, due to the activity of microorganisms and more specially sulfate-reducing bacteria (SRB). SRB are obligate anaerobes using sulphate as electron acceptor with resultant production of sulphide. Some of them are also able to use hydrogen as energy source, causing cathodic depolarization of steel surfaces. An experiment was performed to analyze the relation between SRB activity and use of different cathodic potentials applied to mild steel samples in marine sediments. Analytical techniques employed included lipid bio-markers and electrochemical methods. Results indicated an evolution of the bacterial community structure both on the steel and in the sediment, as a function of time and potential. The results also show that cathodically produced hydrogen promotes the growth of SRB (author) [fr

Determination of distribution coefficient (Kd's) of some artificial and naturally occurring radionuclide in fresh and marine coastal water sediment

International Nuclear Information System (INIS)

Al-Masri, M. S.; Mamish, S; Haleem, M. A.

2004-12-01

Distribution coefficients of artificial and natural radionuclides in fresh and marine water sediment are used in modeling radionuclide dispersion in water system, and the radiation risk and environmental investigating of impact of radioactive emissions, due to routine operations of nuclear plants or disposal and burial of radioactive waste in the environment. In the present work, distribution coefficient of uranium, lead, polonium, radium (naturally occurring radionuclides that may be emitted into the Syrian environment by the phosphate and oil industry with relatively high concentrations) and caesium 137 and strontium 85, in fresh water sediment (Euphrates River, Orantos River and Mzzerib Lake) and marine coastal water (Lattakia, Tartous and Banias). Distribution coefficients were found to vary between (5.8-17.18)*10 3 , (2.2-8.11)*10 3 , (0.22-2.08)*10 3 , (0.16-0.19)*10 3 , (0.38-0.69)*10 3 and 49-312 for polonium, lead, uranium, radium, cesium and strontium respectively. Results have indicated that most measurement distribution coefficients in the present study were lower than those values reported in IAEA documents for marine coastal sediment. In addition, variations of Kd's with aqueous phase composition and sediment elemental and mineralogical composition and its total organic materials content have been studied, where liner correlation coefficients for each isotope with different parameters have been determined. The obtained data reported in this study can be used for radioactive contaminants dispersion and transfer in Syrian river, lake and coast to assess risks to public due to discharges of the phosphate and oil industry into the Syrian environment. (Authors)

Distribution of the dominant microbial communities in marine sediments containing high concentrations of gas hydrates

Energy Technology Data Exchange (ETDEWEB)

Briggs, B.; Colwell, F.; Carini, P.; Torres, M. [Oregon State Univ., Corvallis, OR (United States); Hangsterfer, A.; Kastner, M. [California Univ., San Diego, CA (United States). Scripps Inst. of Oceanography; Brodie, E. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Center for Environmental Biotechnology; Daly, R. [California Univ., Berkeley, CA (United States); Holland, M. [GeoTek, Daventry, Northants (United Kingdom); Long, P.; Schaef, H. [Pacific Northwest National Laboratory, Richland, WA (United States). Environmental Technology; Delwiche, M. [Idaho National Laboratory, Idaho Falls, ID (United States). Biotechnology; Winters, W. [United States Geological Survey, Woods Hole, MA (United States). Woods Hole Science Center; Riedel, M. [McGill Univ., Montreal, PQ (Canada). Dept. of Earth and Planetary Sciences

2008-07-01

Methane produced by microorganisms represents a large portion of the methane that occurs in marine sediments where gas hydrates are present. The diverse communities that populate these formations have been documented by cultures or through molecular traces. Previous studies have explored the biogeography of hydrate-bearing systems by comparing clone libraries developed from sediments where hydrates are abundant with those developed from sediments that lack hydrates. There is a distinct microbial community present in sediments that have methane hydrates. This paper presented an investigation into finer-scale biogeography, in order to determine how factors such as the presence or absence of hydrates, grain size, and the depositional environment in marine sediments may control the number, type and distribution of microbial communities in sediments. The purpose of the study was to understand the controls on the distribution and activity of all microbes that contribute to the conversion of organic matter to methane. To this aim, DNA was extracted from deep marine sediments cored from continental slope locations including offshore India and the Cascadia Margin. The data from the study was used to refine computational models that require biological rate terms that are consistent with sediment conditions in order to accurately describe the dynamics of this large methane reservoir. The paper discussed the materials and methods used for the study, including the sample site, sample collection and microbiological analysis. Results were presented in terms of DNA extractions; microbial diversity; and biofilm analyses. It was concluded that the findings from the study complemented previously reported studies which indicated the presence of diverse microbial communities in sediments containing methane hydrates. 9 refs., 5 figs.

Levels of Cd, Cu, Pb and V in marine sediments in the vicinity of the Single Buoy Moorings (SBM3) at Mina Al Fahal in the Sultanate of Oman.

Science.gov (United States)

Al-Husaini, Issa; Abdul-Wahab, Sabah; Ahamad, Rahmalan; Chan, Keziah

2014-06-15

Recently in the Sultanate of Oman, there has been a rapid surge of coastal developments. These developments cause metal contamination, which may affect the habitats and communities at and near the coastal region. As a result, a study was conducted to assess the level of metal contamination and its impact on the marine sediments in the vicinity of the Single Buoy Moorings 3 (SBM3) at Mina Al Fahal in the Sultanate of Oman. Marine subtidal sediment samples were collected from six different stations of the SBM3 for the period ranging from June 2009 to April 2010. These samples were then analyzed for their level and distribution of the heavy metals of cadmium (Cd), copper (Cu), lead (Pb) and vanadium (V). Overall, low concentrations of all four heavy metals were measured from the marine sediments, indicating that the marine at SBM3 is of good quality. Copyright © 2014 Elsevier Ltd. All rights reserved.

Levels of Cd, Cu, Pb and V in marine sediments in the vicinity of the Single Buoy Moorings (SBM3) at Mina Al Fahal in the Sultanate of Oman

International Nuclear Information System (INIS)

Al-Husaini, Issa; Abdul-Wahab, Sabah; Ahamad, Rahmalan; Chan, Keziah

2014-01-01

Highlights: • Assessed metal contamination in the SBM3 marine sediments of Mina Al Fahal, Oman. • Examined heavy metal concentration levels of Cd, Cu, Pb and V. • Mean concentration in the sediments, from highest to lowest, is V > Cu > Pb > Cd. • Highest concentration of V due to waste discharges from nearby heavy tanker traffic. • ICP-OES found low concentrations of all four heavy metals; SMB3 region in good quality. - Abstract: Recently in the Sultanate of Oman, there has been a rapid surge of coastal developments. These developments cause metal contamination, which may affect the habitats and communities at and near the coastal region. As a result, a study was conducted to assess the level of metal contamination and its impact on the marine sediments in the vicinity of the Single Buoy Moorings 3 (SBM3) at Mina Al Fahal in the Sultanate of Oman. Marine subtidal sediment samples were collected from six different stations of the SBM3 for the period ranging from June 2009 to April 2010. These samples were then analyzed for their level and distribution of the heavy metals of cadmium (Cd), copper (Cu), lead (Pb) and vanadium (V). Overall, low concentrations of all four heavy metals were measured from the marine sediments, indicating that the marine at SBM3 is of good quality

Dynamic transition of chemolithotrophic sulfur-oxidizing bacteria in response to amendment with nitrate in deposited marine sediments

Directory of Open Access Journals (Sweden)

Tomo eAoyagi

2015-05-01

Full Text Available Although environmental stimuli are known to affect the structure and function of microbial communities, their impact on the metabolic network of microorganisms has not been well investigated. Here, geochemical analyses, high-throughput sequencing of 16S rRNA genes and transcripts, and isolation of potentially relevant bacteria were carried out to elucidate the anaerobic respiration processes stimulated by nitrate (20 mM amendment of marine sediments. Marine sediments deposited by the Great East Japan Earthquake in 2011 were incubated anaerobically in the dark at 25°C for 5 days. Nitrate in slurry water decreased gradually for 2 days, then more rapidly until its complete depletion at day 5; production of N2O followed the same pattern. From day 2 to 5, the sulfate concentration increased and the sulfur content in solid-phase sediments significantly decreased. These results indicated that denitrification and sulfur oxidation occurred simultaneously. Illumina sequencing revealed the proliferation of known sulfur oxidizers, i.e., Sulfurimonas spp. and Chromatiales bacteria, which accounted for approximately 43.5% and 14.8% of the total population at day 5, respectively. They also expressed 16S rRNA to a considerable extent, whereas the other microorganisms, e.g., iron(III reducers and methanogens, became metabolically active at the end of the incubation. Extinction dilution culture in a basal-salts medium supplemented with sulfur compounds and nitrate successfully isolated the predominant sulfur oxidizers: Sulfurimonas sp. strain HDS01 and Thioalkalispira sp. strain HDS22. Their 16S rRNA genes showed 95.2−96.7% sequence similarity to the closest cultured relatives and they grew chemolithotrophically on nitrate and sulfur. Novel sulfur-oxidizing bacteria were thus directly involved in carbon fixation under nitrate-reducing conditions, activating anaerobic respiration processes and the reorganization of microbial communities in the deposited marine

Cumulative human impacts on marine predators.

Science.gov (United States)

Maxwell, Sara M; Hazen, Elliott L; Bograd, Steven J; Halpern, Benjamin S; Breed, Greg A; Nickel, Barry; Teutschel, Nicole M; Crowder, Larry B; Benson, Scott; Dutton, Peter H; Bailey, Helen; Kappes, Michelle A; Kuhn, Carey E; Weise, Michael J; Mate, Bruce; Shaffer, Scott A; Hassrick, Jason L; Henry, Robert W; Irvine, Ladd; McDonald, Birgitte I; Robinson, Patrick W; Block, Barbara A; Costa, Daniel P

2013-01-01

Stressors associated with human activities interact in complex ways to affect marine ecosystems, yet we lack spatially explicit assessments of cumulative impacts on ecologically and economically key components such as marine predators. Here we develop a metric of cumulative utilization and impact (CUI) on marine predators by combining electronic tracking data of eight protected predator species (n=685 individuals) in the California Current Ecosystem with data on 24 anthropogenic stressors. We show significant variation in CUI with some of the highest impacts within US National Marine Sanctuaries. High variation in underlying species and cumulative impact distributions means that neither alone is sufficient for effective spatial management. Instead, comprehensive management approaches accounting for both cumulative human impacts and trade-offs among multiple stressors must be applied in planning the use of marine resources.

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)

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)

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

Science.gov (United States)

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

2013-12-01

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

Effects of terrestrial and marine organic matters on deposition of dechlorane plus (DP) in marine sediments from the Southern Yellow Sea, China: Evidence from multiple biomarkers

International Nuclear Information System (INIS)

Wang, Guoguang; Peng, Jialin; Hao, Ting; Feng, Lijuan; Liu, Qiaoling; Li, Xianguo

2017-01-01

As an emerging halogenated organic contaminant, Dechlorane Plus (DP) was scarcely reported in marine environments, especially in China. In this work, 35 surface sediments and a sediment core were collected across the Southern Yellow Sea (SYS) to comprehensively explore the spatio-temporal distribution and possible migration pathway of DP. DP concentrations ranged from 14.3 to 245.5 pg/g dry weight in the surface sediments, displaying a seaward increasing trend with the high levels in the central mud zone. This spatial distribution pattern was ascribed to that fine particles with the elevated DP levels were preferentially transported to the central mud zone under hydrodynamic forcing and/or via long-range atmospheric transportation and deposition. DP concentrations in sediment core gradually increased from the mid-1950s to present, which corresponded well with the historical production and usage of DP, as well as the economic development in China. Significantly positive correlation between DP and total organic carbon (TOC) in both surface sediments and sediment core indicated TOC-dependent natural deposition of DP in the SYS. We used multiple biomarkers, for the first time, to explore the potential effects of terrestrial and marine organic matters (TOM and MOM) on DP deposition. The results showed that competition may occur between TOM and MOM for DP adsorption, and MOM was the predominant contributor in controlling DP deposition in the marine sediments from the SYS. - Highlights: • Effects of TOM and MOM on DP deposition were first explored by multi-biomarkers. • Hydrodynamic forcing and atmospheric deposition were responsible for DP in the SYS. • MOM was the predominant contributor in controlling DP deposition to sediments in the SYS. • Competition may occur between TOM and MOM for DP adsorption. - This study was the first attempt to comprehensively explore the effects of TOM and MOM on DP deposition in marine sediments from the SYS.

USE OF ULVA LACTUCA TO DISTINGUISH PH DEPENDENT TOXICANTS IN MARINE WATERS AND SEDIMENTS

Science.gov (United States)

Ulva lactuca (sea lettuce) is a cosmopolitan marine attached green seaweed capable of sequestering high environmental levels of ammonia. Ammonia can be acutely toxic to marine organisms and is often found in dredged sediments from highly industrial areas or from areas with high c...

Elucidating Microbial Species-Specific Effects on Organic Matter Transformation in Marine Sediments

Science.gov (United States)

Mahmoudi, N.; Enke, T. N.; Beaupre, S. R.; Teske, A.; Cordero, O. X.; Pearson, A.

2017-12-01

Microbial transformation and decomposition of organic matter in sediments constitutes one of the largest fluxes of carbon in marine environments. Mineralization of sedimentary organic matter by microorganisms results in selective degradation such that bioavailable or accessible compounds are rapidly metabolized while more recalcitrant, complex compounds are preserved and buried in sediment. Recent studies have found that the ability to use different carbon sources appears to vary among microorganisms, suggesting that the availability of certain pools of carbon can be specific to the taxa that utilize the pool. This implies that organic matter mineralization in marine environments may depend on the metabolic potential of the microbial populations that are present and active. The goal of our study was to investigate the extent to which organic matter availability and transformation may be species-specific using sediment from Guaymas Basin (Gulf of California). We carried out time-series incubations using bacterial isolates and sterilized sediment in the IsoCaRB system which allowed us to measure the production rates and natural isotopic signatures (δ13C and Δ14C) of microbially-respired CO2. Separate incubations using two different marine bacterial isolates (Vibrio sp. and Pseudoalteromonas sp.) and sterilized Guaymas Basin sediment under oxic conditions showed that the rate and total quantity of organic matter metabolized by these two species differs. Approximately twice as much CO2 was collected during the Vibrio sp. incubation compared to the Pseudoalteromonas sp. incubation. Moreover, the rate at which organic matter was metabolized by the Vibrio sp. was much higher than the Pseudoalteromonas sp. indicating the intrinsic availability of organic matter in sediments may depend on the species that is present and active. Isotopic analyses of microbially respired CO2 will be used to constrain the type and age of organic matter that is accessible to each species

Thermally induced motion of marine sediments resulting from disposal of radioactive wastes

International Nuclear Information System (INIS)

Chavez, P.F.; Dawson, P.R.

1981-01-01

Coupled creep and heat transfer calculations have been performed to assess the sensitivity of heat load, viscosity, and canister density on the motion of waste canisters buried in marine sediments. Results indicate that no upward movement is predicted for heat loads remaining within the metallurgical and geochemical constraints placed on the temperature of sediments near the canister for the times analyzed. Upward movement of the canister is again not observed in calculations involving reasonable variations of the sediment viscosity and canister density. Maximum effective deviatoric stress levels due to thermally induced differential body forces are significantly less than the sediment's short term peak strength

Optically stimulated luminescence (OSL) dating of shallow marine sediments to develop an analysis method of late Quaternary geodynamics

International Nuclear Information System (INIS)

Hataya, Ryuta; Shirai, Masaaki

2003-01-01

To develop an analysis method of geodynamics, we have examined the applicability of the OSL dating of marine terrace deposits. We have done the OSL dating, using the multiple-aliquot additive-dose technique, of shallow marine sediments from the upper part the Kioroshi Formation in Ibaraki Prefecture, which are correlated to Marine Oxygen Isotope Stage (MIS) 5e-5c. Marine terrace deposit consists mainly of shallow marine sediment. OSL ages of foreshore and foreshore-shoreface beds are 88-112 Ka, and are in good agreement with the geological/geomorphological data. On the other hand, OSL ages of the backshore bed are younger, and ones of the shoreface bed are older than geologically estimated ages. These results show that OPSL dating method can date shallow marine sediment using samples from foreshore and foreshore-shoreface beds, and that this method can distinguish terrace deposits formed in MIS5 and that in MIS7 by taking geomorphologic information into account. These results contribute to the characterization of long-term geological movement in coastal areas. (author)

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

Science.gov (United States)

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

2014-12-01

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

[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.

Comparison of test specific sediment effect concentrations with marine sediment quality assessment guidelines

International Nuclear Information System (INIS)

Carr, R.S.; Biedenbach, J.M.; MacDonald, D.D.

1995-01-01

As part of NOAA's National Status and Trends (NS and T) Bioeffects Assessment program and studies conducted by the National Biological Service, numerous sediment quality assessment surveys have recently been conducted along the Atlantic and Gulf coasts of the US using the sea urchin (Arbacia punctulata) fertilization and embryological development tests with pore water. Additional toxicity tests were also conducted in conjunction with most of these studies. The areas that have been sampled include Boston harbor, Massachusetts; Charleston Harbor, Winyah Bay, and Savannah River, South Carolina; St. Simon Sound, Georgia; Biscayne Bay, Tampa Bay, Choctawhatchee Bay, Apalachicola Bay, St. Andrew Bay, and Pensacola Bay, Florida; Galveston Bay, Lavaca Bay, and Sabine Lake, Texas, and 200 stations in the vicinity of offshore oil and gas production platforms in the Gulf of Mexico. Sufficient data are now available from this series of surveys to calculate test specific sediment effect concentrations (SECs). Based on these recent studies, SECs were developed for the sea urchin porewater and amphipod tests and compared with existing marine sediment quality assessment guidelines

Lead isotopic signatures in Antarctic marine sediment cores: A comparison between 1 M HCl partial extraction and HF total digestion pre-treatments for discerning anthropogenic inputs

International Nuclear Information System (INIS)

Townsend, A.T.; Snape, I.; Palmer, A.S.; Seen, A.J.

2009-01-01

Sensitive analytical techniques are typically required when dealing with samples from Antarctica as even low concentrations of contaminants can have detrimental environmental effects. Magnetic Sector ICP-MS is an ideal technique for environmental assessment as it offers high sensitivity, multi-element capability and the opportunity to determine isotope ratios. Here we consider the Pb isotope record of five marine sediment cores collected from three sites in the Windmill Islands area of East Antarctica: Brown Bay adjacent to the current Australian station Casey, Wilkes near the abandoned US/Australian Station and McGrady Cove lying midway between the two. Two sediment pre-treatment approaches were considered, namely partial extraction with 1 M HCl and total dissolution involving HF. Lead isotope ratio measurements made following sediment partial extraction provided a more sensitive indication of Pb contamination than either Pb concentrations alone (irrespective of sample pre-treatment method) or isotope ratios made after HF digestion, offering greater opportunity for discrimination between impacted and natural/geogenic samples and sites. Over 90% of the easily extractable Pb from sediments near Casey was anthropogenic in origin, consisting of Pb from major Australian deposits. At Wilkes impact from discarded batteries with a unique isotopic signature was found to be a key source of Pb contamination to the marine environment with ∼ 70-80% of Pb being anthropogenic in origin. The country and source of origin of these batteries remain unknown. Little evidence was found suggesting contamination at Wilkes by Pb originating from the major US source, Missouri. No definitive assessment could be made regarding Pb impact at McGrady Cove as the collected sediment core was of insufficient depth. Although Pb isotope ratio signatures may indicate anthropogenic input, spatial concentration gradients at nearby Brown Bay suggest contamination at McGrady Cove is unlikely. We

Impact of Bacterial NO>3- Transport on Sediment Biogeochemistry

DEFF Research Database (Denmark)

Nielsen, Lars Peter

2005-01-01

Experiments demonstrated that Beggiatoa could induce a H2S-depleted suboxic zone of more than 10 mm in marine sediments and cause a divergence in sediment NO3- reduction from denitrification to dissimilatory NO3- reduction to ammonium. pH, O2, and H2S profiles indicated that the bacteria oxidized H......2S with NO3- and transported S0 to the sediment surface for aerobic oxidation....

Radioactivity, radiological risk and metal pollution assessment in marine sediments from Calabrian selected areas, southern Italy

Science.gov (United States)

Caridi, F.; Messina, M.; Faggio, G.; Santangelo, S.; Messina, G.; Belmusto, G.

2018-02-01

The two most significant categories of physical and chemical pollutants in sediments (radionuclides and metals) were investigated in this article, in order to evaluate pollution levels in marine sediments from eight different selected sites of the Calabria region, south of Italy. In particular samples were analyzed to determine natural and anthropic radioactivity and metal concentrations, in order to assess any possible radiological hazard, the level of contamination and the possible anthropogenic impact in the investigated area. Activity concentrations of 226Ra, 232Th, 40K and 137Cs were measured by High Purity Germanium (HPGe) gamma spectrometry. The obtained results show that, for radium (in secular equilibrium with uranium), the specific activity ranges from ( 14 ± 1) Bq/kg dry weight (d.w.) to ( 54 ± 9) Bq/kg d.w.; for thorium, from ( 12 ± 1) Bq/kg d.w. to ( 83 ± 8) Bq/kg d.w.; for potassium, from ( 470 ± 20) Bq/kg d.w. to ( 1000 ± 70) Bq/kg d.w. and for cesium it is lower than the minimum detectable activity value. The absorbed gamma dose rate in air (D), the annual effective dose equivalent (AEDE) outdoor and the external hazard index ( H_ex) were calculated to evaluate any possible radiological risk, mainly due to the use of marine sediments for the beach nourishment. The results show low levels of radioactivity, thus discarding any significant radiological risk. Some metals (As, Cd, Cr tot, Hg, Ni, Pb, Cu, Zn, Mn and Fe), that could be released into the environment by both natural and anthropogenic sources, were investigated through inductively coupled plasma mass spectrometry (ICP-MS) measurements and compared with the limits set by the Italian Legislation, to assess any possible contamination. Experimental results show that they are much lower than the contamination threshold value, thus excluding their presence as pollutants. The degree of sediment contaminations were quantified using enrichment factor ( EF) and geoaccumulation index ( I geo) for

137Cs in marine sediments of Admiralty Bay, King George Island, Antarctica

International Nuclear Information System (INIS)

Ferreira, Paulo Alves de Lima; Ribeiro, Andreza Portella; Nascimento, Mylene Giseli do; Martins, Cesar de Castro; Mahiques, Michel Michaelovitch de; Montone, Rosalinda Carmelo; Figueira, Rubens Cesar Lopes

2013-01-01

The radionuclide cesium-137 ( 137 Cs) is produced exclusively by anthropogenic processes and primarily by nuclear explosions. This study determined the reference inventory that is 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. 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 −2 , and within the ambient 137 Cs activity range. A model of 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 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 137 Cs in marine sediments when used as a tracer for environmental processes and for assessing potential bioavailability. - Highlights: ► Cesium-137 ( 137 Cs) is produced exclusively by anthropogenic processes. ► A model of diffusion–convection simulated 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

Development of a chronic sediment toxicity test for marine benthic amphipods

International Nuclear Information System (INIS)

DeWitt, T.H.; Redmond, M.S.; Sewall, J.E.; Swartz, R.C.

1992-12-01

The results of the research effort culminated in the development of a research method for assessing the chronic toxicity of contaminated marine and estuarine sediments using the benthic amphipod, Leptocheirus plumulosus. The first chapter describes the efforts at collecting, handling, and culturing four estuarine amphipods from Chesapeake Bay, including L. plumulosus. This chapter includes maps of the distribution and abundance of these amphipods within Chesapeake Bay and methodologies for establishing cultures of amphipods which could be readily adopted by other laboratories. The second chapter reports the development of acute and chronic sediment toxicity test methods for L. plumulosus, its sensitivity to non-contaminant environmental variables, cadmium, two polynuclear aromatic hydrocarbons, and contaminated sediment from Baltimore Harbor, MD. The third chapter reports the authors attempts to develop a chronic sediment toxicity test with Ampelisca abdita

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.

Analytical methods for measuring 10Be in marine sediments

International Nuclear Information System (INIS)

Graham, I.J.; Ditchburn, R.G.; Sparks, R.J.; Whitehead, N.E.

1995-01-01

A suite of marine sediments from the Wanganui Basin (Graham et al. 1995) has provided excellent material to further develop methods for 10 Be analysis at the Institute of Geological and Nuclear Sciences AMS facility. Chemical methods for Be extraction have been streamlined and there has been some reduction of backgrounds and contamination peaks for 1 0Be isotopic analysis. (authors) 12 refs., 5 figs., 1 tab

Time Matters: Increasing the Efficiency of Antarctic Marine Geology and Paleoceanography Expeditions by Providing Improved Sediment Chronology

Science.gov (United States)

Rosenheim, B. E.; Domack, E. W.; Shevenell, A.; Subt, C.

2015-12-01

To maximize the areal extent of Antarctic sedimentary records of past deglaciation, it is necessary to ensure more sediment cores can be adequately dated. Antarctic margin sediment is challenging to date due to the lack of preserved calcium carbonate, but the records contained in these sediments readily recount the history of deglaciation. Recent and continued development of new chronological methods for Antarctic margin sediments have allowed better use of the efforts of marine geological coring expeditions to the region. The development of Ramped PyrOx radiocarbon dating has allowed us to 1. improve dates in deglacial sediments where no carbonate is preserved, 2. date glacial sediments lying below the tills marking the last glaciation, and 3. compile core chronologies into a regional framework of ice shelf collapse that has eluded many marine geology campaigns over the last few decades. These advances in a fundamental aspect of geological sciences will put the U.S. and international community on a better foothold to interpret the past as it relates to our warming future. We will present these advances in chronology as well as the science that is enabled by them, while arguing that the future of Antarctic marine science also depends on investments in shore-based technologies that come at a relatively low cost.

Spatial and seasonal variations of Acid Volatile Sulfide (AVS) and Simultaneously Extracted Metals (SEM) in Dutch marine and freshwater sediments

NARCIS (Netherlands)

Hoop MAGT van den; Hollander HA den; Kerdijk HN; LAC; ECO; Delft Hydraulics

1995-01-01

Within the framework of the project Exposure Assessment, Acid Volatile Sulfide (AVS) and Simultaneously Extracted Metal (SEM) contents of Dutch marine and freshwater sediments were determined. For the present set of fifteen marine and six freshwater sediments AVS levels vary between non-detectable

REMOVAL OF AMMONIA TOXCITY IN MARINE SEDIMENT TIES: A COMPARISON OF ULVA LACTUCA, ZEOLITE AND AREATION METHODS

Science.gov (United States)

Ammonia is suspected of causing some of the toxicity observed in marine sediment toxicity tests because it is sometimes found at elevated concentrations in marine interstitial waters. In marine waters, ammonia exists as un-ionized ammonia (NH3) and ammonium (NH4+) which combine ...

Radioactivity of some alpha, beta and gamma emitting radionuclides in surface marine sediments of different bays in Algeria

International Nuclear Information System (INIS)

Noureddine, A.; Baggoura, B.

1999-01-01

Samples of surface (0-15) cm marine sediments of different grain sizes, namely sand, muddy and fine sand, were collected in the western, central and east coast of Algeria, to measure concentrations of natural and artificial radioactivity. The aim of this study is to detect any radioactive contamination, its origin and also to determine the uptake of radioactivity by marine surface sediments

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

Science.gov (United States)

Yang, Na; Song, Fuhang

2018-02-01

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.

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

Evaluation of the presence of major anionic surfactants in marine sediments.

Science.gov (United States)

Cantarero, S; Camino-Sánchez, F J; Zafra-Gómez, A; Ballesteros, O; Navalón, A; Vílchez, J L; Verge, C; Reis, M S; Saraiva, P M

2012-03-01

The contamination of aquatic environments has become the focus of increasing regulation and public concern due to their potential and unknown negative effects on the ecosystems. The present work develops a monitoring and statistical study, based on the analysis of variance test (ANOVA) and the multivariable analysis, both for insoluble soap and LAS in order to compare the behavior of different anionic surfactants in this environmental compartment. First, a novel and successfully validated methodology to analyze insoluble soap in these samples is developed. The matrix effect and the comparison of different extraction techniques were also performed. The optimized analytical methodologies were applied to 48 representative samples collected from the Almeria Coast (Spain) and then a statistical analysis to correlate anionic surfactant concentration and several variables associated with marine sediment samples was also developed. The results obtained showed relevant conclusions related to the environmental behavior of anionic surfactants in marine sediments. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

Digital Repository Service at National Institute of Oceanography (India)

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

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

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...

Relevance of carbon stocks of marine sediments for national greenhouse gas inventories of maritime nations.

Science.gov (United States)

Avelar, Silvania; van der Voort, Tessa S; Eglinton, Timothy I

2017-12-01

Determining national carbon stocks is essential in the framework of ongoing climate change mitigation actions. Presently, assessment of carbon stocks in the context of greenhouse gas (GHG)-reporting on a nation-by-nation basis focuses on the terrestrial realm, i.e., carbon held in living plant biomass and soils, and on potential changes in these stocks in response to anthropogenic activities. However, while the ocean and underlying sediments store substantial quantities of carbon, this pool is presently not considered in the context of national inventories. The ongoing disturbances to both terrestrial and marine ecosystems as a consequence of food production, pollution, climate change and other factors, as well as alteration of linkages and C-exchange between continental and oceanic realms, highlight the need for a better understanding of the quantity and vulnerability of carbon stocks in both systems. We present a preliminary comparison of the stocks of organic carbon held in continental margin sediments within the Exclusive Economic Zone of maritime nations with those in their soils. Our study focuses on Namibia, where there is a wealth of marine sediment data, and draws comparisons with sediment data from two other countries with different characteristics, which are Pakistan and the United Kingdom. Results indicate that marine sediment carbon stocks in maritime nations can be similar in magnitude to those of soils. Therefore, if human activities in these areas are managed, carbon stocks in the oceanic realm-particularly over continental margins-could be considered as part of national GHG inventories. This study shows that marine sediment organic carbon stocks can be equal in size or exceed terrestrial carbon stocks of maritime nations. This provides motivation both for improved assessment of sedimentary carbon inventories and for reevaluation of the way that carbon stocks are assessed and valued. The latter carries potential implications for the management of

Relevance of carbon stocks of marine sediments for national greenhouse gas inventories of maritime nations

Directory of Open Access Journals (Sweden)

Silvania Avelar

2017-05-01

Full Text Available Abstract Background Determining national carbon stocks is essential in the framework of ongoing climate change mitigation actions. Presently, assessment of carbon stocks in the context of greenhouse gas (GHG-reporting on a nation-by-nation basis focuses on the terrestrial realm, i.e., carbon held in living plant biomass and soils, and on potential changes in these stocks in response to anthropogenic activities. However, while the ocean and underlying sediments store substantial quantities of carbon, this pool is presently not considered in the context of national inventories. The ongoing disturbances to both terrestrial and marine ecosystems as a consequence of food production, pollution, climate change and other factors, as well as alteration of linkages and C-exchange between continental and oceanic realms, highlight the need for a better understanding of the quantity and vulnerability of carbon stocks in both systems. We present a preliminary comparison of the stocks of organic carbon held in continental margin sediments within the Exclusive Economic Zone of maritime nations with those in their soils. Our study focuses on Namibia, where there is a wealth of marine sediment data, and draws comparisons with sediment data from two other countries with different characteristics, which are Pakistan and the United Kingdom. Results Results indicate that marine sediment carbon stocks in maritime nations can be similar in magnitude to those of soils. Therefore, if human activities in these areas are managed, carbon stocks in the oceanic realm—particularly over continental margins—could be considered as part of national GHG inventories. Conclusions This study shows that marine sediment organic carbon stocks can be equal in size or exceed terrestrial carbon stocks of maritime nations. This provides motivation both for improved assessment of sedimentary carbon inventories and for reevaluation of the way that carbon stocks are assessed and valued. The

Tracking riverborne sediment and contaminants in Commencement Bay, Washington, using geochemical signatures

Science.gov (United States)

Takesue, Renee K.; Conn, Kathleen E.; Dinicola, Richard S.

2017-09-29

Large rivers carry terrestrial sediment, contaminants, and other materials to the coastal zone where they can affect marine biogeochemical cycles and ecosystems. This U.S. Geological Survey study combined river and marine sediment geochemistry and organic contaminant analyses to identify riverborne sediment and associated contaminants at shoreline sites in Commencement Bay, Puget Sound, Washington, that could be used by adult forage fish and other marine organisms. Geochemical signatures distinguished the fine fraction (contaminants were measured in surface sediment did not have measurable 7Be activities in that layer, so their contaminant assemblages were attributed to sources from previous years. Concentrations of organic contaminants (the most common of which were polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and fecal sterols) were higher in the contaminants in marine rather than river sediment, indicates that riverborne sediment-bound contaminants are retained in shallow marine habitats of Commencement Bay. The retention of earlier inputs complicates efforts to identify recent inputs and sources. Understanding modern sources and fates of riverborne sediment and contaminants and their potential ecological impacts will therefore require a suite of targeted geochemical studies in such marine depositional environments.

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.J.; 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

Concentration of 60Co by marine organisms through sediments

International Nuclear Information System (INIS)

Nakahara, Motokazu; Koyanagi, Taku; Saiki, Masamichi

1976-01-01

Uptake of 60 Co absorbed on sea sands by benthic marine organisms was observed in laboratory experiments, since the radioactive cobalt released from nuclear power plants or other establishments into coastal seawater trends to be absorbed on sea sediments and also various kinds of marine organisms live in bottom sediments. Few kinds of flatfishes (Limanda spp.) and shrimp (Trachypenaeus curvirostris) were reared in aquariums contained seawater and sea sands which were highly contaminated with 60 Co previously, and whole body retention and distribution of radioactivity were measured on the organisms taken up from the aquariums occasionally by a scintillation counter. Uptake of 60 Co from ingested sea sands was also observed on the flatfishes administrating the contaminated sands orally. Concentration of 60 Co by the flatfishes reared in the sands was not significant while the shrimp showed high retention of the radioactivity. The food habit of shrimp which usually feeds on organic detritus with other small benthic organisms is different from that of flatfishes, one of the carnivorous, and considered to bring the difference on the pathway of radionuclides concentration. Assimilation of 60 Co via the digestive tract of flatfishes through the sands was estimated as about 10 per cent of the administrated radioactivity. (auth.)

Cs-137 in Marine Sediments of the Eastern Mediterranean from the Pre-Chernobyl Age to the Present

Energy Technology Data Exchange (ETDEWEB)

Florou, H.; Evangeliou, N.; Kritidis, P. [Demokritos National Center for Scientific Research, Institute of Nuclear Technology-Radiation Protection, Environmental Radioactivity Laboratory (ERL), Athens (Greece)

2013-07-15

A survey of the {sup 137}Cs inventory in sediments from the Greek marine environment is presented for the period 1984 to 2007, based on published and unpublished data of ERL. A retrospective summary of the {sup 137}Cs impact assessment is also attempted, based on data covering the period prior to and after Chernobyl up to 2007. Therefore, the sinking time and the ecological half-life of {sup 137}Cs are also estimated in some specific areas of the Eastern Mediterranean and the findings are compared to the deposition data of the first days of the Chernobyl impact. By evaluating all these findings and estimations, a {sup 137}Cs distribution pattern is proposed considering the Chernobyl impact as a case study in this area. (author)

Optimizing sample pretreatment for compound-specific stable carbon isotopic analysis of amino sugars in marine sediment

Science.gov (United States)

Zhu, R.; Lin, Y.-S.; Lipp, J. S.; Meador, T. B.; Hinrichs, K.-U.

2014-09-01

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. Compound-specific stable carbon isotopic analysis of amino sugars obtained from marine sediment extracts indicated that glucosamine and galactosamine were mainly derived from organic detritus, whereas muramic acid showed isotopic imprints from indigenous bacterial activities. The δ13C analysis of amino sugars provides a valuable addition to the biomarker-based characterization of microbial metabolism in the deep marine biosphere, which so far has been lipid oriented and biased towards the detection of archaeal signals.

Radioactivity and metal concentrations in marine sediments associated with mining activities in Ierissos Gulf, North Aegean Sea, Greece

International Nuclear Information System (INIS)

Pappa, F.K.; Tsabaris, C.; Ioannidou, A.; Patiris, D.L.; Kaberi, H.; Pashalidis, I.; Eleftheriou, G.; Androulakaki, E.G.; Vlastou, R.

2016-01-01

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 "2"2"6Ra, "2"3"5U 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. - Highlights: • Baseline information of radionuclides in a coastal area near a mining site. • Trace metals measurements in marine sediment. • Dose rates assessment for marine biota using ERICA Assessment Tool.

Gold-bearing fluvial and associated tidal marine sediments of Proterozoic age in the Mporokoso Basin, northern Zambia

Science.gov (United States)

Andrews-Speed, C. P.

1986-07-01

The structurally defined Mporokoso Basin contains up to 5000 m of continental and marine clastic sediments and minor silicic volcanics which together form the Mporokoso Group. These rocks overlie unconformably a basement of silicic-intermediate igneous rocks and accumulated within the interval 1830-1130 Ma. This sedimentological study was restricted to the eastern end of the basin and was part of an assessment of the potential for palaeoplacer gold in the Mporokoso Group. At the base of the Mporokoso Group, the Mbala Formation consists of 1000-1500 m of purple sandstones and conglomerates deposited in a braided-stream system overlain by 500-1000 m of mature quartz arenites deposited in a tidal marine setting. A general coarsening-upward trend exists within the fluvial sediments. Sandy, distal braided-stream facies passes upwards into more proximal conglomeratic facies. In proximal sections, poorly sorted conglomerates form the top of the coarsening-up sequence which is 500-700 m thick. The overlying fluvial sediments fine upwards. The tidal marine sandstones at the top of the Mbala Formation resulted from reworking of fluvial sediments during a marine transgression. Well-exposed sections with fluvial conglomerates were studied in detail. Individual conglomerate bodies form sheets extending for hundreds of metres downstream and at least one hundred metres across stream, with little sign of deep scouring or channelling. They are generally matrix-supported. The whole fluvial sequence is characterised by a paucity of mud or silt. These conglomerates were deposited by large velocity, sheet flows of water which transported a bed-load of pebbles and sand. Most fine material settling out from suspension was eroded by the next flow. The great lateral and vertical extent and the uniformity of the fluvial sediments suggest that the sediments accumulated over an unconfined alluvial plain and that the tectonic evolution of the source area was relatively continuous and not

Impacts of discarded plastic bags on marine assemblages and ecosystem functioning.

Science.gov (United States)

Green, Dannielle Senga; Boots, Bas; Blockley, David James; Rocha, Carlos; Thompson, Richard

2015-05-05

The accumulation of plastic debris is a global environmental problem due to its durability, persistence, and abundance. Although effects of plastic debris on individual marine organisms, particularly mammals and birds, have been extensively documented (e.g., entanglement and choking), very little is known about effects on assemblages and consequences for ecosystem functioning. In Europe, around 40% of the plastic items produced are utilized as single-use packaging, which rapidly accumulate in waste management facilities and as litter in the environment. A range of biodegradable plastics have been developed with the aspiration of reducing the persistence of litter; however, their impacts on marine assemblages or ecosystem functioning have never been evaluated. A field experiment was conducted to assess the impact of conventional and biodegradable plastic carrier bags as litter on benthic macro- and meio-faunal assemblages and biogeochemical processes (primary productivity, redox condition, organic matter content, and pore-water nutrients) on an intertidal shore near Dublin, Ireland. After 9 weeks, the presence of either type of bag created anoxic conditions within the sediment along with reduced primary productivity and organic matter and significantly lower abundances of infaunal invertebrates. This indicates that both conventional and biodegradable bags can rapidly alter marine assemblages and the ecosystem services they provide.

Chronic Exposure of Corals to Fine Sediments: Lethal and Sub-Lethal Impacts

Science.gov (United States)

Flores, Florita; Hoogenboom, Mia O.; Smith, Luke D.; Cooper, Timothy F.; Abrego, David; Negri, Andrew P.

2012-01-01

Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS) for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata) more than the upright branching species (Acropora millepora). The lowest sediment treatments that caused full colony mortality were 30 mg l−1 TSS (25 mg cm−2 day−1) for M. aequituberculata and 100 mg l−1 TSS (83 mg cm−2 day−1) for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue. PMID:22662225

Chronic exposure of corals to fine sediments: lethal and sub-lethal impacts.

Directory of Open Access Journals (Sweden)

Florita Flores

Full Text Available Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata more than the upright branching species (Acropora millepora. The lowest sediment treatments that caused full colony mortality were 30 mg l(-1 TSS (25 mg cm(-2 day(-1 for M. aequituberculata and 100 mg l(-1 TSS (83 mg cm(-2 day(-1 for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue.

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

DEFF Research Database (Denmark)

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

2009-01-01

Arctic regions may be particularly sensitive to climate warming and, consequently, rates of carbon mineralization in warming marine sediment may also be affected. Using long-term (24 months) incubation experiments at 0°C, 10°C and 20°C, the temperature response of metabolic activity and community...... composition of sulfate-reducing bacteria were studied in the permanently cold sediment of north-western Svalbard (Arctic Ocean) and compared with a temperate habitat with seasonally varying temperature (German Bight, North Sea). Short-term 35S-sulfate tracer incubations in a temperature-gradient block...... (between -3.5°C and +40°C) were used to assess variations in sulfate reduction rates during the course of the experiment. Warming of arctic sediment resulted in a gradual increase of the temperature optima (Topt) for sulfate reduction suggesting a positive selection of psychrotolerant/mesophilic sulfate...

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

DEFF Research Database (Denmark)

Na, Hyunsoo

. While we did not find methanogens to be involved in acetate consumption with sediment incubations, the results from co-culture experiments show that syntrophic growth may allow aceticlastic methanogens to co-exist with sulfate-reducing bacteria in anoxic, sulfate-rich marine environments....... are largely unknown. The main goal of my PhD project was to identify acetate consumers in sulfate-reducing sediments of Aarhus Bay, Denmark. More specifically, we addressed the hypothesis if sulfate-reducing bacteria and methanogenic archaea can oxidize acetate in syntrophy. First, we examined the changes...... sulfate for a year were comparable to those of sediment incubated with high sulfate, on phylum/class levels, but within Deltaproteobacteria, certain sulfate reducers such as Desulfobacterium anilini was found only with low sulfate. In continuous flow-through reactors, bacteria mainly involved in sulfur...

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

Science.gov (United States)

Keil, Richard

2017-01-03

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.

Accumulation of heavy metals in sediments of marine environments along the southwest coast of India

International Nuclear Information System (INIS)

Manjunatha, B.R.; Yeats, P.A.; Smith, J.N.; Shankar, R.; Narayana, A.C.; Prakash, T.N.

1999-01-01

In order to estimate the rate of excessive sediment accumulation that causes navigational problems and the impacts of urban and industrial development on sediment quality, concentrations of Cu, Ni, Zn, Cr, Mn, Fe and Ca, and radioactivity levels of 210 Pb and 137 Cs have been measured in nineteen sediment cores from estuarine, lagoonal, marsh, backwater and inner shelf areas along the southwest coast of India. Sediment accumulation rates in estuarine, lagoonal, marshy areas of the Karnataka coast (ELMKC) and Cochin Backwaters (CBw) are three to six times higher than those in the adjacent inner shelf areas, consistent with the deposition of terrigenous sediments in the river-sea interaction zones. Hydrogen sulphide was detected in most of the samples; sediment colour varied from shades of gray to dark green. Sediments have lower elemental concentrations and element enrichment factors (EFs) particularly for redox sensitive elements such as Mn due to prevalence of reducing conditions in the sedimentary column. Sediments of ELMKC and CBw have a predominantly terrigenous source. They contain low Ca contents, characteristic of tropical river sediments. In contrast, a higher Ca content of inner shelf sediments off both Karnataka State (ISKS-1) and Kerala State (ISKS-2) implies the importance of additional sediment (CaCO 3 ) flux from the marine biota. Measured Cu, Ni and Zn concentrations are generally low, perhaps reflecting the pristine nature of sediments. However, higher concentrations of Cr at all stations and of Zn at CBw indicate the input of Cr enriched minerals like amphibole and pyroxene from the catchment as well as Zn from anthropogenic sources. Heavy metal accumulation rates are high in estuarine, lagoonal, marsh and backwater areas along the southwest coast of India. This is not only due to the proximity of sources, but also due to high sediment accumulation rates because of the reduction of river flow in river-sea interaction zones owing to particle

Speedy instrumental decoding of the marine-sediment as an indicator of environment pollution (abstract)

International Nuclear Information System (INIS)

Rehana, I.; Ishfaq, M.M.

1999-01-01

Pedogenesis and drainage determine quantity and quality of material to be transported from the terrestrial ecosystem to aquatic ecosystem. Thus identification of controlling factors for the accumulation of certain elemental burden is important while, studying recent anthropogenic sources on soil and ground water elemental geochemistry. The continuous supply of organic and inorganic material in aquatic system such as lake, rivers and estuaries renders the sediment-water interface by marked chemical changes, resulting in steep gradients in physical, chemical and biological properties. Biogenic, authigenic and mineral particle which settle at the sediment surface accumulate to relatively high concentration and compared to their time in water column, have an appreciably long time in which to react mutually henceforth to the surrounding interacting forces. The particle flux in the ocean response to wind speed, aerosol deposition, nutrient level, carbon dioxide levels in the mixed layer, availability of the trace element such as Fe and volcanic emissions. Biochemical processes taking place in the deep ocean are coupled to the atmospheric processes via the particle flux in the ocean. As the oceanic flux, responds to the climatic and environmental forces, it has also a potential to detect and monitor, thus permitting the reconstruction of the global changes in the past. Thus, in spite of the fact that are distinct correlation between concentration and the distance of the sampling point from potential source such as industry, highway or municipal can not be established sediments from sea, lake, estuaries or river could be valuable tool to show spatial and temporal trends of metal contamination. Studies have been undertaken to construct a comprehensive scenario of environmental impact from marine pollution. Hence present work attempts to evaluate enrichment of various metals and cations in marine sediments from Japanese and Pakistan coastal areas. Concentration of Cr, Cu, Cd

Diversity and characterization of culturable fungi from marine sediment collected from St. Helena Bay, South Africa

CSIR Research Space (South Africa)

Mouton, M

2012-08-01

Full Text Available origins. It has not been proven whether these fungi merely survive the harsh environmental conditions presented by the ocean sediment, as opposed to playing an active role in this ecological niche. During this study, marine sediment was collected from St...

Analysis of marine sediment and lobster hepatopancreas reference materials by instrumental photon activation

International Nuclear Information System (INIS)

Landsberger, S.; Davidson, W.F.

1985-01-01

By use of instrumental photon activation analysis, twelve trace (As, Ba, Cr, Co, Mn, Ni, Pb, Sb, Sr, U, Zn, and Zr) and eight minor (C, Na, Mg, Co, K, Ca, Tl, and Fe) elements were determined in a certified marine sediment standard reference material as well as eight trace (Mn, Ni, Cu, Zn, As, Sr, Cd, and Pb) and four minor (Na, Mg, Cl, and Ca) elements in a certified marine tissue (lobster hepatopancreas) standard reference material. The precision and accuracy of the present results when compared to the accepted values clearly demonstrate the reliability of this nondestructive technique and its applicability to marine environmental or marine geochemical studies. 24 references, 4 figures, 3 tables

A global survey of the distribution of free gas in marine sediments

Science.gov (United States)

Fleischer, Peter; Orsi, Tim; Richardson, Michael

2003-10-01

Following the work of Aubrey Anderson in the Gulf of Mexico, we have attempted to quantify the global distribution of free gas in shallow marine sediments, and have identified and indexed over one hundred documented cases in the scientific and engineering literature. Our survey confirms previous assumptions, primarily that gas bubbles are ubiquitous in the organic-rich muds of coastal waters and shallow adjacent seas. Acoustic turbidity as recorded during seismo-acoustic surveys is the most frequently cited evidence used to infer the presence of seafloor gas. Biogenic methane predominates within these shallow subbottom deposits. The survey also reveals significant imbalances in the geographic distribution of studies, which might be addressed in the future by accessing proprietary data or local studies with limited distribution. Because of their global prevalence, growing interest in gassy marine sediments is understandable as their presence has profound scientific, engineering and environmental implications.

Are Sediments a Source of Fukushima Radiocesium for Marine Fauna in Coastal Japan?

Science.gov (United States)

Wang, C.; Fisher, N. S.; Baumann, Z.

2016-02-01

The Fukushima nuclear power plant accident in 2011 resulted in the largest accidental release of artificial radionuclides into the world's oceans. Among the fission products released in large quantities, 137Cs has the greatest potential for long-term impacts on marine biota and human consumers of seafood. In particular, some species of bottom fish near Fukushima were very contaminated and had higher radiocesium (134Cs and 137Cs) levels than pelagic fish in the same area, sometimes exceeding Japanese safety limits >4 years after the accident. Benthic invertebrates, many being prey items for bottom fish, show the same slow decrease in radiocesium as sediments, suggesting that contaminated sediment could be a source of radiocesium for benthic fauna. We evaluated the binding of 137Cs to sediments (Kd found to be 44-60 ml g-1) and found that bioturbation by the polychaete Nereis succinea greatly increased the initial release rate of Cs to overlying seawater. We also assessed the bioavailability of dissolved and sediment-bound Cs for deposit-feeding polychaetes, and its subsequent transfer to crabs and fish, and measured the influence of water temperature on Cs accumulation in fish. Assimilation efficiency (AE) of ingested 137Cs ranged from 16% in polychaetes ingesting sediments to 79% in fish ingesting worms. Efflux rate constants ranged from 5% d-1 for killifish to 40% d-1 for polychaetes. Animal absorption and retention of dissolved 137Cs were also measured. These parameters are used to model radiocesium bioaccumulation and trophic transfer in benthic food chains. Our results are consistent with the idea that sediments can be an important source of Cs for benthic food chains and help explain why some species of bottom fish remained more contaminated than pelagic fish in Japanese coastal waters.

The distribution of triclosan and methyl-triclosan in marine sediments of Barker Inlet, South Australia.

Science.gov (United States)

Fernandes, Milena; Shareef, Ali; Kookana, Rai; Gaylard, Sam; Hoare, Sonja; Kildea, Tim

2011-04-01

In this work, we investigated the transport and burial of triclosan and its methylated derivative, in surface sediments near the mouth of Barker Inlet in South Australia. The most likely source of this commonly used bactericide to the area is a wastewater outfall discharging at the confluence of the inlet with marine waters. Triclosan was detected in all samples, at concentrations (5-27 μg kg(-1)) comparable to values found in other surface sediments under the influence of marine wastewater outfalls. Its dispersal was closely associated with fine and organic-rich fractions of the sediments. Methyl-triclosan was detected in approximately half of the samples at concentrations compound was linked to both wastewater discharges and biological methylation of the parent compound. Wastewater-borne methyl-triclosan had a smaller spatial footprint than triclosan and was mostly deposited in close proximity to the outfall. In situ methylation of triclosan likely occurs at deeper depositional sites, whereas the absence of methyl-triclosan from shallower sediments was potentially explained by photodegradation of the parent compound. Based on partition equilibrium, a concentration of triclosan in the order of 1 μg L(-1) was estimated in sediment porewaters, a value lower than the threshold reported for harmful effects to occur in the couple of species of marine phytoplankton investigated to date. Methyl-triclosan presents a greater potential for bioaccumulation than triclosan, but the implications of its occurrence to aquatic ecosystem health are difficult to predict given the lack of ecotoxicological data in the current literature.

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...

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

Cumulative human impacts on marine predators

DEFF Research Database (Denmark)

Maxwell, Sara M; Hazen, Elliott L; Bograd, Steven J

2013-01-01

Stressors associated with human activities interact in complex ways to affect marine ecosystems, yet we lack spatially explicit assessments of cumulative impacts on ecologically and economically key components such as marine predators. Here we develop a metric of cumulative utilization and impact...

Wave Glider Monitoring of Sediment Transport and Dredge Plumes in a Shallow Marine Sandbank Environment.

Science.gov (United States)

Van Lancker, Vera; Baeye, Matthias

2015-01-01

As human pressure on the marine environment increases, safeguarding healthy and productive seas increasingly necessitates integrated, time- and cost-effective environmental monitoring. Employment of a Wave Glider proved very useful for the study of sediment transport in a shallow sandbank area in the Belgian part of the North Sea. During 22 days, data on surface and water-column currents and turbidity were recorded along 39 loops around an aggregate-extraction site. Correlation with wave and tidal-amplitude data allowed the quantification of current- and wave-induced advection and resuspension, important background information to assess dredging impacts. Important anomalies in suspended particulate matter concentrations in the water column suggested dredging-induced overflow of sediments in the near field (i.e., dynamic plume), and settling of finer-grained material in the far field (i.e., passive plume). Capturing the latter is a successful outcome to this experiment, since the location of dispersion and settling of a passive plume is highly dependent on the ruling hydro-meteorological conditions and thus difficult to predict. Deposition of the observed sediment plumes may cause habitat changes in the long-term.

Wave Glider Monitoring of Sediment Transport and Dredge Plumes in a Shallow Marine Sandbank Environment.

Directory of Open Access Journals (Sweden)

Vera Van Lancker

Full Text Available As human pressure on the marine environment increases, safeguarding healthy and productive seas increasingly necessitates integrated, time- and cost-effective environmental monitoring. Employment of a Wave Glider proved very useful for the study of sediment transport in a shallow sandbank area in the Belgian part of the North Sea. During 22 days, data on surface and water-column currents and turbidity were recorded along 39 loops around an aggregate-extraction site. Correlation with wave and tidal-amplitude data allowed the quantification of current- and wave-induced advection and resuspension, important background information to assess dredging impacts. Important anomalies in suspended particulate matter concentrations in the water column suggested dredging-induced overflow of sediments in the near field (i.e., dynamic plume, and settling of finer-grained material in the far field (i.e., passive plume. Capturing the latter is a successful outcome to this experiment, since the location of dispersion and settling of a passive plume is highly dependent on the ruling hydro-meteorological conditions and thus difficult to predict. Deposition of the observed sediment plumes may cause habitat changes in the long-term.

Can sediments at hydrocarbon seep sites represent a source for marine bioavailable iron? — A case study from the South China Sea

Science.gov (United States)

Li, N.; Feng, D.; Chen, D.

2017-12-01

Niu Li1, Dong Feng1,2, and Duofu Chen2,31CAS Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China. 2Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China. 3Hadal Science and Technology Research Center, College of Marine Sciences, Shanghai Ocean University, Shanghai 201306, China. Iron is an essential micronutrient and commonly considered to be one of the key-limiting factors for biological productivity in many ocean regions. Seafloor Fe supply should be most efficient in suboxic conditions. Recent studies shown that widely spread anoxic environments can develop in hydrocarbon seep sediment and local bottom water, owing to the occurrence of aerobic and/or anaerobic methane oxidation. Under this condition, the iron in sediment can be reduced to dissolved Fe2+ in the ocean. However, questions remain about whether the hydrocarbon seep sediment can represent a source for bioavailable iron to the ocean, and the control factor for the transformation of iron in the sediment remains largely unexplored. For a number of hydrocarbon seeps from the northern and southern South China Sea, the iron speciation, pyrite sulfur isotope, and iron isotope, as well as the major and trace elements are used to constrain the intensity of cold seep, and its impact on transformation of iron in sediment. Samples from both areas show sediment iron lost during the high methane flux conditions, owing to the suboxic conditions cause by aerobic methane oxidation. On the other hand, high sediment iron content accompanied by high sulfur content can be seen during the conditions of high methane flux without the occurrence of aerobic methane oxidation, which is possible ascribed to the anaerobic methane oxidation and the release of iron through seep activity. This study reveals the transformation of iron in the sediment is closely related to the

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

Science.gov (United States)

Yazdani Foshtomi, Maryam; Braeckman, Ulrike; Derycke, Sofie; Sapp, Melanie; Van Gansbeke, Dirk; Sabbe, Koen; Willems, Anne; Vincx, Magda; Vanaverbeke, Jan

2015-01-01

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 activity. We

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

Mineralogy, early marine diagenesis, and the chemistry of shallow-water carbonate sediments

Science.gov (United States)

Higgins, J. A.; Blättler, C. L.; Lundstrom, E. A.; Santiago-Ramos, D. P.; Akhtar, A. A.; Crüger Ahm, A.-S.; Bialik, O.; Holmden, C.; Bradbury, H.; Murray, S. T.; Swart, P. K.

2018-01-01

Shallow-water carbonate sediments constitute the bulk of sedimentary carbonates in the geologic record and are widely used archives of Earth's chemical and climatic history. One of the main limitations in interpreting the geochemistry of ancient carbonate sediments is the potential for post-depositional diagenetic alteration. In this study, we use paired measurements of calcium (44Ca/40Ca or δ44Ca) and magnesium (26Mg/24Mg or δ26Mg) isotope ratios in sedimentary carbonates and associated pore-fluids as a tool to understand the mineralogical and diagenetic history of Neogene shallow-water carbonate sediments from the Bahamas and southwest Australia. We find that the Ca and Mg isotopic composition of bulk carbonate sediments at these sites exhibits systematic stratigraphic variability that is related to both mineralogy and early marine diagenesis. The observed variability in bulk sediment Ca isotopes is best explained by changes in the extent and style of early marine diagenesis from one where the composition of the diagenetic carbonate mineral is determined by the chemistry of the fluid (fluid-buffered) to one where the composition of the diagenetic carbonate mineral is determined by the chemistry of the precursor sediment (sediment-buffered). Our results indicate that this process, together with variations in carbonate mineralogy (aragonite, calcite, and dolomite), plays a fundamental and underappreciated role in determining the regional and global stratigraphic expressions of geochemical tracers (δ13C, δ18O, major, minor, and trace elements) in shallow-water carbonate sediments in the geologic record. Our results also provide evidence that a large shallow-water carbonate sink that is enriched in 44Ca can explain the mismatch between the δ44/40Ca value of rivers and deep-sea carbonate sediments and call into question the hypothesis that the δ44/40Ca value of seawater depends on the mineralogy of primary carbonate precipitations (e.g. 'aragonite seas' and

Environmental risk assessment of triclosan and ibuprofen in marine sediments using individual and sub-individual endpoints.

Science.gov (United States)

Pusceddu, F H; Choueri, R B; Pereira, C D S; Cortez, F S; Santos, D R A; Moreno, B B; Santos, A R; Rogero, J R; Cesar, A

2018-01-01

The guidelines for the Environmental Risk Assessment (ERA) of pharmaceuticals and personal care products (PPCP) recommend the use of standard ecotoxicity assays and the assessment of endpoints at the individual level to evaluate potential effects of PPCP on biota. However, effects at the sub-individual level can also affect the ecological fitness of marine organisms chronically exposed to PPCP. The aim of the current study was to evaluate the environmental risk of two PPCP in marine sediments: triclosan (TCS) and ibuprofen (IBU), using sub-individual and developmental endpoints. The environmental levels of TCS and IBU were quantified in marine sediments from the vicinities of the Santos submarine sewage outfall (Santos Bay, São Paulo, Brazil) at 15.14 and 49.0 ng g -1 , respectively. A battery (n = 3) of chronic bioassays (embryo-larval development) with a sea urchin (Lytechinus variegatus) and a bivalve (Perna perna) were performed using two exposure conditions: sediment-water interface and elutriates. Moreover, physiological stress through the Neutral Red Retention Time Assay (NRRT) was assessed in the estuarine bivalve Mytella charruana exposed to TCS and IBU spiked sediments. These compounds affected the development of L. variegatus and P. perna (75 ng g -1 for TCS and 15 ng g -1 for IBU), and caused a significant decrease in M. charruana lysosomal membrane stability at environmentally relevant concentrations (0.08 ng g -1 for TCS and 0.15 ng g -1 for IBU). Chemical and ecotoxicological data were integrated and the risk quotient estimated for TCS and IBU were higher than 1.0, indicating a high environmental risk of these compounds in sediments. These are the first data of sediment risk assessment of pharmaceuticals and personal care products of Latin America. In addition, the results suggest that the ERA based only on individual-level and standard toxicity tests may overlook other biological effects that can affect the health of marine organisms

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.

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

Viability of microcomputed tomography to study tropical marine worm galleries in humid muddy sediments

International Nuclear Information System (INIS)

Pennafirme, Simone F.; Machado, Alessandra S.; Lima, Inaya; Suzuki, Katia N.; Lopes, Ricardo T.

2013-01-01

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 within the

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.

{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.

Fate of dispersed marine fuel oil in sediment under pre-spill application strategy

International Nuclear Information System (INIS)

Jian Hua

2004-01-01

A comparison of the movement of dispersed oil in marine sediment under two dispersant application scenarios, applied prior to and after oil being spilled overboard, was examined. The pre-spill application scenario caused much less oil to be retained in the top sediment than post-spill scenario. The difference in oil retention in the top sediment between pre- and post-spill application scenario increased with increase in fuel oil temperature. For fuel oil above 40 o C, the difference in the effect of pre-spill application strategy under various water temperatures was negligible. When soap water was used as replacement for chemical dispersant, almost one-half as much oil was retained in the top sediment as that when using chemical dispersant. The adsorption of dispersed oil to the top sediment was almost proportionally decreased with doubling of soap dosage. (Author)

Evaluation of experimental studies on technetium transfers to sediments and benthic marine species, and comparison with in situ data

Energy Technology Data Exchange (ETDEWEB)

Aprosi, G [Electricite de France, 78 - Chatou; Masson, M [Commisariat a l' Energie Atomique, Institut de Protection et de Surete Nucleaire, 50 - Cherbourg (France)

1984-01-01

To obtain basic information for the evaluation of the radiological impact of technetium (Tc) on the marine environment, investigations are performed by different laboratories. Technetium is not a natural element and the main source of production is the nuclear fuel cycle. Under anoxic conditions, in presence of reducing sediments, the distribution coefficients are very high (Ksub(D)=10/sup 3/). Concentration factors from water to species are mostly very low (FC 1 to 10); however, concentration factors up to 1000 have been observed for a few species such as macrophytic brown algae, worms and lobster. Biochemical analysis shows that Tc is bound with protein. The transfer factors between sediment and species are very low (FT<0,5). The biological half-life (Tb) was determined in some marine organisms which had accumulated the radionuclide from water-contamined food or from sediments. The loss is biphasic in storage organs (liver and kidney); uptake in the edible parts is low. Among the parameters studied (light for algae, physico-chemical form of Tc, salinity and temperature) only light and the physico-chemical forms have an effect on the accumulation of technetium. Analyses of /sup 99/Tc concentrations in species collected near the La Hague and Windscale (Sellafield) reprocessing plants confirm the experimental studies. Since sea water is likely to be an oxidant environment, technetium appears as a conservative element.

A carbon isotope budget for an anoxic marine sediment

International Nuclear Information System (INIS)

Boehme, S.E.; Blair, N.E.

1991-01-01

A carbon isotope budget has been determined for the coastal marine site, Cape Lookout Bight, NC. Isotope measurements of methane and σCO 2 fluxing out and buried in these sediments were applied to previously measured flux data (Martens et al., in press) to predict the isotopic composition of the incoming metabolizable organic matter. Methane leaves the sediment predominantly via ebullition with an isotopic composition of -60 per mil. Less than 2% of the methane produced is buried with an average diffusional flux value of -17 per mil and a burial value of +11 per mil. The isotope budget predicts a metabolizable organic carbon isotope signature of -19.3 per mil which is in excellent agreement with the measured total organic carbon value of -19.2 ± 0.3 per mil implying that the dominant remineralization processes have been identified

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.

Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria.

Science.gov (United States)

Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

2012-11-01

Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the prevailing terminal electron-accepting process in anoxic incubations of surface sediments, and even the addition of acetate stimulated neither iron nor sulfate reduction. The three geographically distinct sediments harbored surprisingly similar communities of acetate-utilizing manganese-reducing bacteria: 16S rRNA of members of the genera Colwellia and Arcobacter and of novel genera within the Oceanospirillaceae and Alteromonadales were detected in heavy RNA-SIP fractions from these three sediments. Most probable number (MPN) analysis yielded up to 10(6) acetate-utilizing manganese-reducing cells cm(-3) in Gullmar Fjord sediment. A 16S rRNA gene clone library that was established from the highest MPN dilutions was dominated by sequences of Colwellia and Arcobacter species and members of the Oceanospirillaceae, supporting the obtained RNA-SIP results. In conclusion, these findings strongly suggest that (i) acetate-dependent manganese reduction in manganese oxide-rich sediments is catalyzed by members of taxa (Arcobacter, Colwellia and Oceanospirillaceae) previously not known to possess this physiological function, (ii) similar acetate-utilizing manganese reducers thrive in geographically distinct regions and (iii) the identified manganese reducers differ greatly from the extensively explored iron reducers in marine sediments.

High abundance of JS-1- and Chloroflexi-related Bacteria in deeply buried marine sediments revealed by quantitative, real-time PCR.

Science.gov (United States)

Blazejak, Anna; Schippers, Axel

2010-05-01

Sequences of members of the bacterial candidate division JS-1 and the classes Anaerolineae and Caldilineae of the phylum Chloroflexi are frequently found in 16S rRNA gene clone libraries obtained from marine sediments. Using a newly designed quantitative, real-time PCR assay, these bacterial groups were jointly quantified in samples from near-surface and deeply buried marine sediments from the Peru margin, the Black Sea, and a forearc basin off the island of Sumatra. In near-surface sediments, sequences of the JS-1 as well as Anaerolineae- and Caldilineae-related Bacteria were quantified with significantly lower 16S rRNA gene copy numbers than the sequences of total Bacteria. In contrast, in deeply buried sediments below approximately 1 m depth, similar quantities of the 16S rRNA gene copies of these specific groups and Bacteria were found. This finding indicates that JS-1 and Anaerolineae- and Caldilineae-related Bacteria might dominate the bacterial community in deeply buried marine sediments and thus seem to play an important ecological role in the deep biosphere.

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...... was detected accounting for 37-77% of the total NO3- reduced. These contradictory results might be explained by enhanced NO3- availability for DNRA bacteria in the sediment slurries compared to the core-incubated sediments in which diffusion of NO3- from the water column may only reach DEN bacteria...

In Situ Enhancement of Anaerobic Microbial Dechlorination of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Marine and Estuarine Sediments

National Research Council Canada - National Science Library

Haeggblom, Max M; Fennell, Donna E; Kerkhof, Lee J

2006-01-01

... that is associated with dredging, and decrease the cost of sediment management. Reductive dehalogenation is a promising mechanism for the removal of toxic organohalides from estuarine and marine sediments...

Environmental impacts of heavy metals, rare earth elements and natural radionuclides in marine sediment from Ras Tanura, Saudi Arabia along the Arabian Gulf.

Science.gov (United States)

El-Taher, Atef; Alshahri, Fatimh; Elsaman, Reda

2018-02-01

Ras Tanura city is one of the most important cities in Saudi Arabia because of the presence of the largest and oldest oil refinery in the Middle East which was began operations in September 1945. Also its contains gas plant and two ports. The concentration of natural radionuclides, heavy metals and rare earth elements were measured in marine sediment samples collected from Ras Tanura. The specific activities of 238 U, 226 Ra, 232 Th, 40 K and 137 Cs (Bq/kg) were measured using A hyper-pure Germanium detector (HPGe), and ranged from (20.4 ± 4.0-55.1 ± 9.9), (6.71 ± 0.7-46.1 ± 4.5), (3.51 ± 0.5-18.2 ± 1.5), (105 ± 4.4-492 ± 13) and from (0.33 ± 0.04-2.10 ± 0.4) for 238 U, 226 Ra, 232 Th, 40 K and 137 Cs respectively. Heavy metals and rare earth elements were measured using ICPE-9820 Plasma Atomic Emission Spectrometer. Also the frequency distributions for all radioactive variables in sediment samples were analyzed. Finally the radiological hazards due to natural radionuclides in marine sediment were calculated to the public and it's diagramed by Surfer program in maps. Comparing with the international recommended values, its values found to be within the international level. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigating plutonium contamination in marine sediments off Fukushima coast following the Fukushima Dai-ichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

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

2013-01-01

The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident has caused large amounts of anthropogenic radionuclides to be released into the atmosphere as well as directly discharged into the sea. To obtain the vertical distribution of Pu isotopes in marine sediments and to better assess the possible contamination from the FDNPP accident in the marine environment, activities of "2"3"9"+"2"4"0Pu and "2"4"1Pu, as well as the atom ratios of "2"4"0Pu/"2"3"9Pu and "2"4"1Pu/"2"3"9Pu, were investigated in a sediment core collected from the western North Pacific in July 2011. The observed vertical profile of "2"3"9"+"2"4"0Pu activities and "2"4"0Pu/"2"3"9Pu atom ratios showed no extra injection of Pu from the accident, indicating no immediate Pu contamination from the FDNPP accident in the marine sediments in the region investigated. (author)

Metal concentrations and mobility in marine sediment and groundwater in coastal reclamation areas: A case study in Shenzhen, China

International Nuclear Information System (INIS)

Chen Kouping; Jiao, Jiu J.

2008-01-01

The concentrations of metals in the buried marine sediment and groundwater were differently affected by land reclamation. Nine metals (V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb) in sediment and coastal groundwater from reclamation areas in Shenzhen were examined. The gradually decreased concentrations (V, Cr, Mn, Ni, Cu, Zn) in sediment and relatively higher concentrations (V, Cr, Mn, Co, Ni, Cu and Cd) in groundwater within reclamation areas were observed. The increase of V, Cr, Mn, Ni, Cu and Cd concentrations in groundwater within reclamation areas subsequently after land reclamation should be resulted from the mobilization of these metals accumulated in the sediment. These metals appear to be easily mobilized from solid phase to solution phase after reclamation. The physico-chemical changes such as reduction in pH and salinity in water environment induced by land reclamation appear to be responsible for metal mobility in the sediment-groundwater system. - Metals in coastal groundwater and marine sediment are affected by land reclamation

Anthropogenic infilling of a Bermudian sinkhole and its impact on sedimentation and benthic foraminifera in the adjacent anchialine cave environment

Directory of Open Access Journals (Sweden)

Jacquelyn N. Cresswell

2017-09-01

Full Text Available In the mid-20th century, an inland brackish pond from Bermuda, known as Eve’s Pond, was filled with marine sediment from an adjacent coastal lagoon. At this time, an eyewitness reported “…sediment billowing out of the Green Bay Cave for days…”, which is a marine-dominated anchialine cave located proximal to the former location of Eve’s Pond (~200 m. The purpose of this study was to evaluate the potential impact of this infilling event on cave sedimentation and benthic meiofaunal communities, as proxied by the unicellular protists foraminifera that remain preserved in the sediment record. Eight sediment cores were collected from an underwater passage in Green Bay Cave in a transect towards the location where Eve’s Pond was surveyed in 1901 CE. The sediment cores were analyzed for visual and density changes (photography, X-radiography, textural variability, benthic foraminifera fauna and diversity, and radiocarbon dating. The recovered sediment cores mostly sampled a late Holocene carbonate mud facies that had been described during previous research in the cave, with benthic foraminiferal assemblages post-dating the onset of seawater circulating between the saline groundwater flooding the cave and the adjacent Harrington Sound ~1,900 years ago. However, two cores located further into the cave (cores 13 and 17 contain a carbonate sand layer with lagoon foraminifera that is anomalous with respect to the Holocene depositional history of the cave and is most likely related to the mid-20th century infilling of Eve’s Pond. Examination of these two cores showed that after the infilling event, the community of benthic foraminifera rapidly reverted to pre-impact assemblages with foraminiferal stygophiles (e.g., Spirophthalmidium emaciatum, Sigmoilina tenuis, which were not displaced by new colonizers introduced into the cave by the dredge spoils. We caution that the results cannot be extrapolated to the pelagic crustacean community, but the

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

Electrolysis-driven bioremediation of crude oil-contaminated marine sediments.

Science.gov (United States)

Bellagamba, Marco; Cruz Viggi, Carolina; Ademollo, Nicoletta; Rossetti, Simona; Aulenta, Federico

2017-09-25

Bioremediation is an effective technology to tackle crude oil spill disasters, which takes advantage of the capacity of naturally occurring microorganisms to degrade petroleum hydrocarbons under a range of environmental conditions. The enzymatic process of breaking down oil is usually more rapid in the presence of oxygen. However, in contaminated sediments, oxygen levels are typically too low to sustain the rapid and complete biodegradation of buried hydrocarbons. Here, we explored the possibility to electrochemically manipulate the redox potential of a crude oil-contaminated marine sediment in order to establish, in situ, conditions that are conducive to contaminants biodegradation by autochthonous microbial communities. The proposed approach is based on the exploitation of low-voltage (2V) seawater electrolysis to drive oxygen generation (while minimizing chlorine evolution) on Dimensionally Stable Anodes (DSA) placed within the contaminated sediment. Results, based on a laboratory scale setup with chronically polluted sediments spiked with crude oil, showed an increased redox potential and a decreased pH in the vicinity of the anode of 'electrified' treatments, consistent with the occurrence of oxygen generation. Accordingly, hydrocarbons biodegradation was substantially accelerated (up to 3-times) compared to 'non-electrified' controls, while sulfate reduction was severely inhibited. Intermittent application of electrolysis proved to be an effective strategy to minimize the energy requirements of the process, without adversely affecting degradation performance. Taken as a whole, this study suggests that electrolysis-driven bioremediation could be a sustainable technology for the management of contaminated sediments. Copyright © 2016 Elsevier B.V. All rights reserved.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Instrumental neutron activation analysis of proposed marine sediment reference material (IAEA-158)

International Nuclear Information System (INIS)

Siddique, N.; Waheed, S.

2009-01-01

IAEA-158, sediment prepared by the International Atomic Energy Agency -Marine Environmental Laboratory (IAEA-MEL), Monaco was received under the IAEA Analytical Quality Control Services (AQCS) Intercomparison Programme. Instrumental Neutron Activation Analysis (INAA) was used to determine AI, As, Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Se, Sm, Ta, Tb, Th, V, Vb and Zn in this proposed reference material (RM). Four different irradiation protocols were adopted using a miniature neutron source reactor (MNSR) by varying the irradiation, cooling and counting times. IAEA-405 (Estuarine Sediment) and IAEA-SLI (Lake Sediment) were used as compatible matrix reference materials for quality assurance (QA) purposes. Good agreement between our data and lAEA certified values was obtained providing confidence in the reported data. (author)

Validation of a method to measure plutonium levels in marine sediments in Cuba

International Nuclear Information System (INIS)

Sibello Hernández, Rita Y.; Cartas Aguila, Héctor A.; Cozzella, María Letizia

2008-01-01

The main objective of this research was to develop and to validate a method of radiochemical separation of plutonium, suitable from the economic and practical point of view, in Cuba conditions. This method allowed to determine plutonium activity levels in the marine sediments from Cienfuegos Bay. The selected method of radiochemical separation was that of anionic chromatography and the measure technique was the quadrupole inductively coupled plasma mass spectrometry. The method was applied to a certified reference material, six repetitions were carried out and a good correspondence between the average measured value and the average certified value of plutonium was achieved, so the trueness of the method was demonstrated. It was also proven the precision of the method, since it was obtained a variation coefficient of 11% at 95% confidence level. The obtained results show that the presence of plutonium in the analyzed marine sediment samples is only due to the global radioactive fallout. (author)

Marine ecology

International Nuclear Information System (INIS)

Anon.

1977-01-01

Studies on marine ecology included marine pollution; distribution patterns of Pu and Am in the marine waters, sediments, and organisms of Bikini Atoll and the influence of physical, chemical, and biological factors on their movements through marine biogeochemical systems; transfer and dispersion of organic pollutants from an oil refinery through coastal waters; transfer of particulate pollutants, including sediments dispersed during construction of offshore power plants; and raft culture of the mangrove oysters

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.

Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria

OpenAIRE

Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

2012-01-01

Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the p...

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

World-wide and regional intercomparison for the determination of trace elements in polluted marine sediment IAEA-356. Report no.56

Energy Technology Data Exchange (ETDEWEB)

Horvat, M; Mee, L D; Oregioni, B [International Atomic Energy Agency, Marine Environment Laboratory, Monaco (Monaco)

1994-09-01

The accurate and precise determination of trace elements in marine sediment samples is an important aspect of geochemical marine pollution studies and for assessing the levels and pathways of marine pollutants. Past intercomparison exercise conducted by the Marine Environment Laboratory of IAEA (formerly the International Laboratory of Marine Radioactivity) has focused upon the near shore sediment (1) and deep sea marine sediment (2) where trace levels of elements was rather low. The present intercomparison exercise on sediment taken from a polluted coastal lagoon was designed in order to fulfill the increased demand for certified reference materials of various origin and the number of parameters that should be studied. Additionally, different instrumental techniques, both nuclear and non-nuclear, were compared, and evaluated. By statistically examining the data from this study, the material can be certified for future use as a reference material. The current exercise was designed not only to test the intercomparability of different instrumental techniques, but also to evaluate the effectiveness of different procedures for sample digestion. Participants were invited to perform 'total' analyses involving, except in the case of neutron activation analysis, a simple partial extraction with 1M hydrochloric acid (2 hours, room temperature). This partial dissolution had a twofold purpose: (i) to differentiate between instrumental (plus contamination during work-up) errors and those resulting from method-specific (matrix) effects; and (ii) to evaluate a simple screening test for the more labile ('easily leached') fraction of trace elements of particular interest to environmental chemists. The present report presents the entire experimental data set and a statistical evaluation of the results for each parameter.

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

Estimation of carbonate concentration and characterization of marine sediments by Fourier transform infrared spectroscopy.

Digital Repository Service at National Institute of Oceanography (India)

Veerasingam, S.; Venkatachalapathy, R.

its saturation horizon is shallower than that calcite [1]. Elements such as Ca2+ and Mg2+, in addition to their substantial contribution to marine sediments, are used biologically in vital cellular processes and in the mineralization of skeletons... such as ocean acidification on ecosystems. Thus, a rapid, cheap and non-destructive tool is required to investigate the distribution of CaCO3 in sediments for the understanding of the fate of biologically produced carbonate. 3    FTIR spectroscopy is one...

Genotoxic and teratogenic potential of marine sediment extracts investigated with comet assay and zebrafish test

International Nuclear Information System (INIS)

Kammann, Ulrike; Biselli, Scarlett; Huehnerfuss, Heinrich; Reineke, Ninja; Theobald, Norbert; Vobach, Michael; Wosniok, Werner

2004-01-01

Organic extracts of marine sediments from the North Sea and the Baltic Sea were investigated with two toxicity assays. The comet assay based on the fish cell line Epithelioma papulosum cyprini (EPC) was applied to determine the genotoxic potential; zebrafish embryos (Danio rerio) were used to quantify the teratogenic potential of the samples. EC 50 values were calculated from dose-response curves for both test systems. Highest teratogenic and genotoxic effects normalised to total organic carbon (TOC) content were detected in sediment samples of different origins. Polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) are not likely to be the causes of the observed effects, as demonstrated by a two-step fractionation procedure of selected extracts. The toxic potential was more pronounced in fractions having polarity higher than those possessed by PAHs and PCBs. The suitability of the two in vitro test systems for assessing genotoxic and teratogenic effects of marine sediment extracts could be demonstrated. - Capsule: In vitro toxicity assays are used to assess genotoxic and teratogenic effects of environmental extracts

Petroleum hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) in Hong Kong marine sediments

International Nuclear Information System (INIS)

Zheng, G.J.; Richardson, B.J.

1999-01-01

A total of 20 surficial sediment samples, obtained from Hong Kong coastal waters, were analysed for petroleum hydrocarbons (PHCs) and a suite of 15 polycyclic aromatic hydrocarbons (PAHs). The results indicate that Hong Kong coastal sediments are often seriously polluted with petroleum related hydrocarbons. This is especially so in heavily urbanised or industrialized localities, such as Kowloon Bay (Victoria Harbour), Tsing Yi North and Tolo Harbour. Petroleum hydrocarbon pollutants in marine sediments are believed to be mainly derived from the transportation of oil, shipping activities, spillages, and industrial, stormwater and waste wastewater discharge. The ratio of unresolved complex mixture (UCM) to n-alkanes, carbon preference index (CPI), and n-C 16 values indicate that the main contribution to petroleum hydrocarbon contamination is via oil and its products. Pollutant sources appear to be stable and continuing when compared with previous data. (author)

CO2 leakage from carbon dioxide capture and storage (CCS) systems affects organic matter cycling in surface marine sediments.

Science.gov (United States)

Rastelli, Eugenio; Corinaldesi, Cinzia; Dell'Anno, Antonio; Amaro, Teresa; Greco, Silvestro; Lo Martire, Marco; Carugati, Laura; Queirós, Ana M; Widdicombe, Stephen; Danovaro, Roberto

2016-12-01

Carbon dioxide capture and storage (CCS), involving the injection of CO 2 into the sub-seabed, is being promoted worldwide as a feasible option for reducing the anthropogenic CO 2 emissions into the atmosphere. However, the effects on the marine ecosystems of potential CO 2 leakages originating from these storage sites have only recently received scientific attention, and little information is available on the possible impacts of the resulting CO 2 -enriched seawater plumes on the surrounding benthic ecosystem. In the present study, we conducted a 20-weeks mesocosm experiment exposing coastal sediments to CO 2 -enriched seawater (at 5000 or 20,000 ppm), to test the effects on the microbial enzymatic activities responsible for the decomposition and turnover of the sedimentary organic matter in surface sediments down to 15 cm depth. Our results indicate that the exposure to high-CO 2 concentrations reduced significantly the enzymatic activities in the top 5 cm of sediments, but had no effects on subsurface sediment horizons (from 5 to 15 cm depth). In the surface sediments, both 5000 and 20,000 ppm CO 2 treatments determined a progressive decrease over time in the protein degradation (up to 80%). Conversely, the degradation rates of carbohydrates and organic phosphorous remained unaltered in the first 2 weeks, but decreased significantly (up to 50%) in the longer term when exposed at 20,000 ppm of CO 2 . Such effects were associated with a significant change in the composition of the biopolymeric carbon (due to the accumulation of proteins over time in sediments exposed to high-pCO 2 treatments), and a significant decrease (∼20-50% at 5000 and 20,000 ppm respectively) in nitrogen regeneration. We conclude that in areas immediately surrounding an active and long-lasting leak of CO 2 from CCS reservoirs, organic matter cycling would be significantly impacted in the surface sediment layers. The evidence of negligible impacts on the deeper sediments should be

Salmon Aquaculture and Antimicrobial Resistance in the Marine Environment

Science.gov (United States)

Buschmann, Alejandro H.; Tomova, Alexandra; López, Alejandra; Maldonado, Miguel A.; Henríquez, Luis A.; Ivanova, Larisa; Moy, Fred; Godfrey, Henry P.; Cabello, Felipe C.

2012-01-01

Antimicrobials used in salmon aquaculture pass into the marine environment. This could have negative impacts on marine environmental biodiversity, and on terrestrial animal and human health as a result of selection for bacteria containing antimicrobial resistance genes. We therefore measured the numbers of culturable bacteria and antimicrobial-resistant bacteria in marine sediments in the Calbuco Archipelago, Chile, over 12-month period at a salmon aquaculture site approximately 20 m from a salmon farm and at a control site 8 km distant without observable aquaculture activities. Three antimicrobials extensively used in Chilean salmon aquaculture (oxytetracycline, oxolinic acid, and florfenicol) were studied. Although none of these antimicrobials was detected in sediments from either site, traces of flumequine, a fluoroquinolone antimicrobial also widely used in Chile, were present in sediments from both sites during this period. There were significant increases in bacterial numbers and antimicrobial-resistant fractions to oxytetracycline, oxolinic acid, and florfenicol in sediments from the aquaculture site compared to those from the control site. Interestingly, there were similar numbers of presumably plasmid-mediated resistance genes for oxytetracycline, oxolinic acid and florfenicol in unselected marine bacteria isolated from both aquaculture and control sites. These preliminary findings in one location may suggest that the current use of large amounts of antimicrobials in Chilean aquaculture has the potential to select for antimicrobial-resistant bacteria in marine sediments. PMID:22905164

Salmon aquaculture and antimicrobial resistance in the marine environment.

Directory of Open Access Journals (Sweden)

Alejandro H Buschmann

Full Text Available Antimicrobials used in salmon aquaculture pass into the marine environment. This could have negative impacts on marine environmental biodiversity, and on terrestrial animal and human health as a result of selection for bacteria containing antimicrobial resistance genes. We therefore measured the numbers of culturable bacteria and antimicrobial-resistant bacteria in marine sediments in the Calbuco Archipelago, Chile, over 12-month period at a salmon aquaculture site approximately 20 m from a salmon farm and at a control site 8 km distant without observable aquaculture activities. Three antimicrobials extensively used in Chilean salmon aquaculture (oxytetracycline, oxolinic acid, and florfenicol were studied. Although none of these antimicrobials was detected in sediments from either site, traces of flumequine, a fluoroquinolone antimicrobial also widely used in Chile, were present in sediments from both sites during this period. There were significant increases in bacterial numbers and antimicrobial-resistant fractions to oxytetracycline, oxolinic acid, and florfenicol in sediments from the aquaculture site compared to those from the control site. Interestingly, there were similar numbers of presumably plasmid-mediated resistance genes for oxytetracycline, oxolinic acid and florfenicol in unselected marine bacteria isolated from both aquaculture and control sites. These preliminary findings in one location may suggest that the current use of large amounts of antimicrobials in Chilean aquaculture has the potential to select for antimicrobial-resistant bacteria in marine sediments.

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

DEFF Research Database (Denmark)

Hubert, Casey; Arnosti, Carol; Brüchert, Volker

2010-01-01

Marine sediments harbour diverse populations of dormant thermophilic bacterial spores that become active in sediment incubation experiments at much higher than in situ temperature. This response was investigated in the presence of natural complex organic matter in sediments of two Arctic fjords......, as well as with the addition of freeze-dried Spirulina or individual high-molecular-weight polysaccharides. During 50°C incubation experiments, Arctic thermophiles catalysed extensive mineralization of the organic matter via extracellular enzymatic hydrolysis, fermentation and sulfate reduction. This high...... reactivity determined the extent of the thermophilic response. Fjord sediments with higher in situ SRR also supported higher SRR at 50°C. Amendment with Spirulina significantly increased volatile fatty acids production and SRR relative to unamended sediment in 50°C incubations. Spirulina amendment also...

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.

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.

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

International Nuclear Information System (INIS)

Furdek, Martina; Mikac, Nevenka; Bueno, Maite; Tessier, Emmanuel; Cavalheiro, Joana; Monperrus, Mathilde

2016-01-01

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.

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

Assessment of 210Po in agricultural soils and marine sediments of the Atlantic and Pacific oceans of Guatemala

International Nuclear Information System (INIS)

Garcia Vela, A.G.

1999-01-01

A radiochemical method consisting of 210 Polonium extraction was made to measure radioactivity in samples of soil and marine sediments of Atlantic and Pacific Ocean. The solution of polonium it was treated to obtain the deposition of the metal over a zinc disc and was measured by alpha espectrometry system based on Planar Ion Planted Silice (PIPS) system. The concern about cultivated soils its consuption products from sea and soil come from these sources. The results shows that activity of 210 Polonium in agricultural soils and marine sediments are below of ALI recommended by international standards

Comparative study of plutonium and americium bioaccumulation from two marine sediments contaminated in the natural environment

International Nuclear Information System (INIS)

Hamilton, T.F.; Smith, J.D.

1991-01-01

Plutonium and americium sediment-animal transfer was studied under controlled laboratory conditions by exposure of the benthic polychaete Nereis diversicolor (O. F. Mueller) to marine sediments contaminated by a nuclear bomb accident (near Thule, Greenland) and nuclear weapons testing (Enewetak Atoll). In both sediment regimes, the bioavailability of plutonium and 241 Am was low, with specific activity in the tissues 241 Am occurred and 241 Am uptake from the Thule sediment was enhanced compared to that from lagoon sediments of Enewetak Atoll. Autoradiography studies indicated the presence of hot particles of plutonium in the sediments. The results highlight the importance of purging animals of their gut contents in order to obtain accurate estimates of transuranic transfer from ingested sediments into tissue. It is further suggested that enhanced transuranic uptake by some benthic species could arise from ingestion of highly activity particles and organic-rich detritus present in the sediments. (author)

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,

Sediment Ksub(d)s and concentration factors for radionuclides in the marine environment

International Nuclear Information System (INIS)

1985-01-01

Both the biological and geochemical processes, which are dependent on the chemical form of the element in question, and the radioactive decay of the nuclide are important parameters in the models used for the calculation of dumping limits for radioactive wastes disposed of in the deep sea. The geochemical processes were not adequately represented in earlier models and only rough approximations of parameters were used in the calculations. This report provides an approach for the calculation of deep-sea sediment distribution coefficients and coastal sediment concentration factors for radionuclides in marine biological materials based, whenever possible, on field data

Anthropogenic impacts on marine ecosystems in Antarctica.

Science.gov (United States)

Aronson, Richard B; Thatje, Sven; McClintock, James B; Hughes, Kevin A

2011-03-01

Antarctica is the most isolated continent on Earth, but it has not escaped the negative impacts of human activity. The unique marine ecosystems of Antarctica and their endemic faunas are affected on local and regional scales by overharvesting, pollution, and the introduction of alien species. Global climate change is also having deleterious impacts: rising sea temperatures and ocean acidification already threaten benthic and pelagic food webs. The Antarctic Treaty System can address local- to regional-scale impacts, but it does not have purview over the global problems that impinge on Antarctica, such as emissions of greenhouse gases. Failure to address human impacts simultaneously at all scales will lead to the degradation of Antarctic marine ecosystems and the homogenization of their composition, structure, and processes with marine ecosystems elsewhere. © 2011 New York Academy of Sciences.

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.

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

Science.gov (United States)

Gontikaki, Evangelia; Thornton, Barry; Cornulier, Thomas; Witte, Ursula

2015-01-01

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.

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......–60% of the total 129I are associated with organic matter in soil and sediment samples. At a soil/sediment pH below 5.0–5.5, 127I and 129I in the organic fraction associate primarily with the humic acid while at soil/sediment pH > 6 129I was mostly found to be bound to fulvic acid. Anoxic conditions seem...... 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...

Assessment of Marine Pollution in İzmir Bay: Heavy Metal and Organic Compound Concentrations in Surficial Sediments

OpenAIRE

AKSU, Ali Engin

2014-01-01

The extent of marine pollution in İzmir Bay is investigated using inorganic and organic geochemical data from surface sediments. The concentrations of 42 elements in 84 samples established that surface sediments in Inner İzmir Bay display significant enrichments in Ag, As, Cd, Cr, Cu, Hg, Mo, P, Pb, Sb, Sn, V, and Zn, associated with notably high concentrations of total organic carbon and sulphur. Organic geochemical data in 14 samples from Inner İzmir Bay showed that these sediments...

The accumulation of radiocesium in coarse marine sediment: Effects of mineralogy and organic matter

International Nuclear Information System (INIS)

Kim, Yeongkyoo; Kim, Kangjoo; Kang, Hee-Dong; Kim, Wan; Doh, Si-Hong; Kim, Do-Sung; Kim, Byoung-Ki

2007-01-01

The controlling factors affecting the accumulation of 137 Cs in marine sediment have not been investigated in detail, especially in coarse grained sediment. Eighty eight coarse marine sediment samples near Wuljin, Korea, were characterized by quantitative X-ray-diffraction (XRD), gamma-ray, and total organic carbon (TOC) analysis. Those factors were then compared. The grain size was in the range of -0.48 to 3.6 Mdφ corresponding to sand grains. TOC content was in the range of 0.06-1.75%, and the concentration of 137 Cs was 137 Cs activity, which was first reported here, probably due to the weathered frayed edge site of biotite produced by a release of K. The samples with low TOC contents showed even better correlation between biotite content and 137 Cs activity. For the entire samples, however, the TOC content showed better correlation with 137 Cs activity than other single factors, indicating that biotite and organic carbon are the most important factors controlling 137 Cs fixation. The combined effect of biotite and TOC for 137 Cs fixation was also confirmed by multiple regression analysis ( 137 Cs activity = 1.712 . TOC (wt%) + 0.202 . biotite (wt%) - 0.097; R 2 = 0.819). The regressed slopes indicated that the 137 Cs-adsorption capacity of TOC was about 8.5 times higher than that of biotite. However, the amount of 137 Cs adsorbed onto biotite was 30% more than that adsorbed onto TOC due to much greater biotite content in the sediment. The role of biotite in fixing 137 Cs becomes more important in sediment with coarser grains, containing little TOC

Economic impacts of marine ecological change

NARCIS (Netherlands)

Groeneveld, Rolf A.; Bartelings, Heleen; Börger, Tobias; Bosello, Francesco; Buisman, Erik; Delpiazzo, Elisa; Eboli, Fabio; Fernandes, Jose A.; Hamon, Katell G.; Hattam, Caroline; Loureiro, Maria; Nunes, Paulo A.L.D.; Piwowarczyk, Joanna; Schasfoort, Femke E.; Simons, Sarah L.; Walker, Adam N.

2018-01-01

Marine ecological change is likely to have serious potential economic consequences for coastal economies all over the world. This article reviews the current literature on the economic impacts of marine ecological change, as well as a number of recent contributions to this literature carried out

Polycyclic aromatic hydrocarbons (PAHs) in continental shelf sediment of China: Implications for anthropogenic influences on coastal marine environment

International Nuclear Information System (INIS)

Liu Liangying; Wang Jizhong; Wei Gaoling; Guan Yufeng; Zeng, Eddy Y.

2012-01-01

Sediments collected from the continental shelf of China, embracing Yellow Sea, inner shelf of the East China Sea (ECS), and the South China Sea (SCS), were analyzed for polycyclic aromatic hydrocarbons (PAHs). The concentrations of anthropogenic PAHs (Σ 18 PAH) were 27–224 ng/g dry weight, with an average of 82 ng/g. Sedimentary PAHs in the continental shelf off China were mainly derived from mixed residues of biomass, coal, and petroleum combustion. Fluvial transport and atmospheric deposition mainly accounted for sediment PAHs in the ECS inner shelf and Yellow Sea (and the SCS), respectively. Furthermore, statistically higher levels of Σ 18 PAH (28–224 ng/g; mean 110 ng/g) in the Yellow Sea sediment than in the SCS sediment (28–109 ng/g; mean 58 ng/g) were probably resulted from higher PAH emissions from coke industry and domestic coal combustion in North China than in South China. - Highlights: ► Coal and biomass combustion was the main origin of PAHs in coastal marine sediment of China. ► Fluvial transport was the main mode for transporting PAHs to the East China Sea inner shelf. ► Atmospheric deposition largely accounted for sediment PAHs in Yellow Sea and the South China Sea. ► Regional energy use pattern in China was responsible for the spatial distribution of PAHs in coastal marine sediment. - Sources, compositions and spatial distributions of PAHs in continental shelf sediments off China are analyzed to estimate anthropogenic influences.

Transfer parameters of radionuclides in the marine environment

International Nuclear Information System (INIS)

1996-03-01

To increase the accuracy of estimation of exposure dose by radionuclides in the marine, the informations of environmental parameter data in the marine were collected, arranged and discussed. The informations were discussed by 'a sectional committee of marine suspended solids and sediment'. The following problems were investigated and the studies were recorded in this report, clear explanation about the distribution factor (kd), the estimation method of kd, the fluctuating factor of kd data (properties of suspension and sediment, differences among the experimental methods), the physical and chemical behavior of radionuclides, sediment of radionuclides by means of sorption to the suspended particles in the marine, sorption of radionuclides into the marine soil (sediment), re-eluent of radionuclides sorpted in the marine soil (sediment), and relation between marine organism and marine suspended materials and sediment. (S.Y.)

Supervised classification of continental shelf sediment off western Donegal, Ireland

Science.gov (United States)

Monteys, X.; Craven, K.; McCarron, S. G.

2017-12-01

Managing human impacts on marine ecosystems requires natural regions to be identified and mapped over a range of hierarchically nested scales. In recent years (2000-present) the Irish National Seabed Survey (INSS) and Integrated Mapping for the Sustainable Development of Ireland's Marine Resources programme (INFOMAR) (Geological Survey Ireland and Marine Institute collaborations) has provided unprecedented quantities of high quality data on Ireland's offshore territories. The increasing availability of large, detailed digital representations of these environments requires the application of objective and quantitative analyses. This study presents results of a new approach for sea floor sediment mapping based on an integrated analysis of INFOMAR multibeam bathymetric data (including the derivatives of slope and relative position), backscatter data (including derivatives of angular response analysis) and sediment groundtruthing over the continental shelf, west of Donegal. It applies a Geographic-Object-Based Image Analysis software package to provide a supervised classification of the surface sediment. This approach can provide a statistically robust, high resolution classification of the seafloor. Initial results display a differentiation of sediment classes and a reduction in artefacts from previously applied methodologies. These results indicate a methodology that could be used during physical habitat mapping and classification of marine environments.

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.

Comparative study of plutonium and americium bioaccumulation from two marine sediments contaminated in the natural environment

Energy Technology Data Exchange (ETDEWEB)

Hamilton, T.F.; Smith, J.D. (Melbourne Univ., Parkville (Australia). Dept. of Inorganic Chemistry); Fowler, S.W.; LaRosa, J.; Holm, E. (International Atomic Energy Agency, Monaco-Ville (Monaco). Lab. of Marine Radioactivity); Aarkrog, A.; Dahlgaard, H. (Risoe National Lab., Roskilde (Denmark))

1991-01-01

Plutonium and americium sediment-animal transfer was studied under controlled laboratory conditions by exposure of the benthic polychaete Nereis diversicolor (O. F. Mueller) to marine sediments contaminated by a nuclear bomb accident (near Thule, Greenland) and nuclear weapons testing (Enewetak Atoll). In both sediment regimes, the bioavailability of plutonium and {sup 241}Am was low, with specific activity in the tissues <1% (dry wt) than in the sediments. Over the first three months, a slight preference in transfer of plutonium over {sup 241}Am occurred and {sup 241}Am uptake from the Thule sediment was enhanced compared to that from lagoon sediments of Enewetak Atoll. Autoradiography studies indicated the presence of hot particles of plutonium in the sediments. The results highlight the importance of purging animals of their gut contents in order to obtain accurate estimates of transuranic transfer from ingested sediments into tissue. It is further suggested that enhanced transuranic uptake by some benthic species could arise from ingestion of highly activity particles and organic-rich detritus present in the sediments. (author).

Effects of the antibiotic ciprofloxacin on the bacterial community structure and degradation of pyrene in marine sediment

International Nuclear Information System (INIS)

Naeslund, Johan; Hedman, Jenny E.; Agestrand, Cecilia

2008-01-01

The ecological consequences of antibiotics in the aquatic environment have been an issue of concern over the past years due to the potential risk for negative effects on indigenous microorganisms. Microorganisms provide important ecosystem services, such as nutrient recycling, organic matter mineralization and degradation of pollutants. In this study, effects of exposure to the antibiotic ciprofloxacin on the bacterial diversity and pollutant degradation in natural marine sediments were studied using molecular methods (T-RFLP) in combination with radiorespirometry. In a microcosm experiment, sediment spiked with 14 C-labelled pyrene was exposed to five concentrations of ciprofloxacin (0, 20, 200, 1000 and 2000 μg L -1 ) in a single dose to the overlying water. The production of 14 CO 2 (i.e. complete mineralization of pyrene) was measured during 11 weeks. Sediment samples for bacterial community structure analysis were taken after 7 weeks. Results showed a significant dose-dependent inhibition of pyrene mineralization measured as the total 14 CO 2 production. The nominal EC 50 was calculated to 560 μg L -1 , corresponding to 0.4 μg/kg d.w. sediment. The lowest effect concentration on the bacterial community structure was 200 μg L -1 , which corresponds to 0.1 μg/kg d.w. sediment. Our results show that antibiotic pollution can be a potential threat to both bacterial diversity and an essential ecosystem service they perform in marine sediment

Sediment transport drives tidewater glacier periodicity.

Science.gov (United States)

Brinkerhoff, Douglas; Truffer, Martin; Aschwanden, Andy

2017-07-21

Most of Earth's glaciers are retreating, but some tidewater glaciers are advancing despite increasing temperatures and contrary to their neighbors. This can be explained by the coupling of ice and sediment dynamics: a shoal forms at the glacier terminus, reducing ice discharge and causing advance towards an unstable configuration followed by abrupt retreat, in a process known as the tidewater glacier cycle. Here we use a numerical model calibrated with observations to show that interactions between ice flow, glacial erosion, and sediment transport drive these cycles, which occur independent of climate variations. Water availability controls cycle period and amplitude, and enhanced melt from future warming could trigger advance even in glaciers that are steady or retreating, complicating interpretations of glacier response to climate change. The resulting shifts in sediment and meltwater delivery from changes in glacier configuration may impact interpretations of marine sediments, fjord geochemistry, and marine ecosystems.The reason some of the Earth's tidewater glaciers are advancing despite increasing temperatures is not entirely clear. Here, using a numerical model that simulates both ice and sediment dynamics, the authors show that internal dynamics drive glacier variability independent of climate.

Anaerobic Methane-Oxidizing Microbial Community in a Coastal Marine Sediment: Anaerobic Methanotrophy Dominated by ANME-3.

Science.gov (United States)

Bhattarai, Susma; Cassarini, Chiara; Gonzalez-Gil, Graciela; Egger, Matthias; Slomp, Caroline P; Zhang, Yu; Esposito, Giovanni; Lens, Piet N L

2017-10-01

The microbial community inhabiting the shallow sulfate-methane transition zone in coastal sediments from marine Lake Grevelingen (The Netherlands) was characterized, and the ability of the microorganisms to carry out anaerobic oxidation of methane coupled to sulfate reduction was assessed in activity tests. In vitro activity tests of the sediment with methane and sulfate demonstrated sulfide production coupled to the simultaneous consumption of sulfate and methane at approximately equimolar ratios over a period of 150 days. The maximum sulfate reduction rate was 5 μmol sulfate per gram dry weight per day during the incubation period. Diverse archaeal and bacterial clades were retrieved from the sediment with the majority of them clustered with Euryarchaeota, Thaumarcheota, Bacteroidetes, and Proteobacteria. The 16S rRNA gene sequence analysis showed that the sediment from marine Lake Grevelingen contained anaerobic methanotrophic Archaea (ANME) and methanogens as archaeal clades with a role in the methane cycling. ANME at the studied site mainly belong to the ANME-3 clade. This study provides one of the few reports for the presence of ANME-3 in a shallow coastal sediment. Sulfate-reducing bacteria from Desulfobulbus clades were found among the sulfate reducers, however, with very low relative abundance. Desulfobulbus has previously been commonly found associated with ANME, whereas in our study, ANME-3 and Desulfobulbus were not observed simultaneously in clusters, suggesting the possibility of independent AOM by ANME-3.

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.

The remobilisation of radionuclides from marine sediments: implications for collective dose assessments

International Nuclear Information System (INIS)

Nicholson, S.; MacKenzie, J.

1988-09-01

A model of the transfer (in either direction) of radioactivity between seawater and the seabed is described. It was developed, in the first instance, for inclusion in marine collective dose assessment codes. A review of radionuclide-sediment interactions with particular emphasis on the remobilisation process is followed by a description of the seabed model, an investigation of the effect of the model on estimates of collective dose, and a discussion of sedimentation in the Irish Sea in the context of radioactive discharges. The inclusion of the seabed model may lead to marked decreases in the collective dose at short integration times for nuclides with a high affinity for sediments. For discharges of such radionuclides into the Irish Sea, remobilisation may lead to a significant increase in collective dose compared with estimates obtained ignoring this phenomenon; and thirdly, remobilisation appears to have little effect on collective doses integrated to infinite time for discharges from three other locations in the UK. It is also shown that inclusion of the seabed model leads to predictions of a high uptake of plutonium by the seabed for Irish Sea discharges without the need for anomalously high sedimentation rates. (author)

Culture-Dependent and Independent Studies of Microbial Diversity in Highly Copper-Contaminated Chilean Marine Sediments

NARCIS (Netherlands)

Besaury, L.; Marty, F.; Buquet, S.; Mesnage, V.; Muijzer, G.; Quillet, L.

2013-01-01

Cultivation and molecular-based approaches were used to study microbial diversity in two Chilean marine sediments contaminated with high (835 ppm) and very high concentrations of copper (1,533 ppm). The diversity of cultivable bacteria resistant to copper was studied at oxic and anoxic conditions,

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 NH 3 -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 SCOD Cr /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 SCOD Cr ; specific growth rate (µ), 0.06 d -1 ; specific nitrification rate (SNR), 0.49 mg NH 3 -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

Impact of mussel bioengineering on fine-grained sediment dynamics in a coastal lagoon: a numerical modelling investigation

DEFF Research Database (Denmark)

Forsberg, Pernille Louise; Lumborg, Ulrik; Bundgaard, Klavs

2017-01-01

Rødsand lagoon in southeast Denmark is a non-tidal coastal lagoon. It is home to a wide range of marine flora and fauna and part of the Natura 2000 network. An increase in turbidity through elevated levels of suspended sediment concentration (SSC) within the lagoon may affect the ecosystem health...... due to reduced light penetration. Increasing SSC levels within Rødsand lagoon could be caused by increasing storm intensity or by a sediment spill from dredging activities west of the lagoon in relation to the planned construction of the Fehmarnbelt fixed link between Denmark and Germany. The aim...... of the study was to investigate the impact of a mussel reef on sediment import and SSC in a semi-enclosed lagoon through the development of a bioengineering modelling application that makes it possible to include the filtrating effect of mussels in a numerical model of the lagoonal system. The numerical...

Application of microwave energy to speed up the alkaline extraction of humic and fulvic acids from marine sediments

International Nuclear Information System (INIS)

Romaris-Hortas, Vanessa; Moreda-Pineiro, Antonio; Bermejo-Barrera, Pilar

2007-01-01

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 deg. 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 Ria de Arousa estuary

Dissolved inorganic carbon and alkalinity fluxes from coastal marine sediments: Model estimates for different shelf environments and sensitivity to global change

NARCIS (Netherlands)

Krumins, V.; Gehlen, M.; Arndt, S.; Van Cappellen, P.; Regnier, P.

2013-01-01

We present a one-dimensional reactive transport model to estimate benthic fluxes of dissolved inorganic carbon (DIC) and alkalinity (AT) from coastal marine sediments. The model incorporates the transport processes of sediment accumulation, molecular diffusion, bioturbation and bioirrigation,

In-situ geophysical measurements in marine sediments: Applications in seafloor acoustics and paleoceanography

Science.gov (United States)

Gorgas, Thomas Joerg

Acoustic in-situ sound speeds and attenuation were measured on the Eel River shelf, CA, with the Acoustic Lance between 5 and 15 kHz to 2.0 meters below seafloor (mbsf). A comparison with laboratory ultrasonic geoacoustic data obtained at 400 kHz on cored sediments showed faster in-situ and ultrasonic sound speeds in coarse-grained deposits in water depths to 60 m than in fine-grained deposits below that contour line. Ultrasonic attenuation was often greater than in-situ values and remained almost constant below 0.4 mbsf in these heterogeneous deposits. In-situ attenuation decreased with depth. These observations partly agree with results from other field studies, and with theoretical models that incorporate intergranular friction and dispersion from viscosity as main controls on acoustic wave propagation in marine sediments. Deviations among in-situ and laboratory acoustic data from the Eel Margin with theoretical studies were linked to scattering effects. Acoustic Lance was also deployed in homogeneous, fine-grained sediments on the inner shelf of SE Korea, where free gas was identified in late-September, but not in mid-September 1999. Free gas was evidenced by an abrupt decrease of in-situ sound speed and by characteristic changes in acoustic waveforms. These results suggest the presence of a gassy sediment layer as shallow as 2 mbsf along the 70 m bathymetry line, and was attributed to a variable abundance of free gas on short-term and/or small-regional scales on the SE Korea shelf. Bulk density variations in marine sediments obtained along the Walvis Ridge/Basin, SW Africa, at Ocean Drilling Program (ODP) Sites 1081 to 1084 were spectral-analyzed to compute high-resolution sedimentation rates (SRs) in both the time- and age domains by correctly identifying Milankovitch cycles (MCs). SRs for the ODP sites yielded age-depth models that often correlate positively with biostratigraphic data and with organic mass accumulation rates (MAR Corg), a proxy for

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

Energy Technology Data Exchange (ETDEWEB)

Kusakabe, M.; Oikawa, S.; Takata, H.; Misonoo, J. [Marine Ecology Research Institute, Tokyo (Japan)

2013-07-01

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 {sup 137}Cs in the surface sediments varied spatially by two orders of magnitude, from 1.7 to 580 Bq kg-dry{sup -1}, and there was no obvious correlation between {sup 137}Cs concentration and the proximity of the sampling location to the accident site. The total inventory of {sup 137}Cs accumulated in the upper 3 cm of surface sediments in the monitoring area was estimated to be 3.78 x 10{sup 13} Bq, that is, 0.1-2% of the total {sup 137}Cs 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 {sup 137}Cs concentration and inventory depended on two main factors: the {sup 137}Cs 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 ({sup 90}Sr, {sup 95}Nb, {sup 110} {sup m}Ag, {sup 125}Sb, {sup 129}Te, and {sup 129} {sup m}Te) in the sediments were also investigated. Activity ratios of these nuclides to {sup 137}Cs suggest that the nuclides themselves were not homogenized before they were removed from seawater to the sediments.

Determination of multi-element composition of Vietnamese marine sediment and tuna fish by k0-standardized neutron activation analysis

International Nuclear Information System (INIS)

Manh-Dung Ho; Quang-Thien Tran; Van-Doanh Ho; Thi-Sy Nguyen

2016-01-01

The k 0 -standardized neutron activation analysis (k 0 -NAA) has been applied for determination of multiple elements (25 elements: Al, As, Ba, Br, Ca, Cl, Co, Cr, Cs, Cu, Eu, Fe, Hg, K, La, Mg, Na, Rb, Sc, Se, Sm, Th, Ti, V and Zn) in marine sediment and tuna fish. About 50 marine sediment and 9 tuna fish samples were collected in two coastal areas of Vietnam. The health risk index (HRI) values of As and Br were higher than 1.0 for the tuna fish. Also, HRI value of Hg was 8.92 × 10 -1 indicating a relatively high potential health risk, whiles Co and Mn with HRIs = 1.56 × 10 -4 and 8.56 × 10 -4 , respectively, have the lowest potential health risks. Average enrichment factors using Al as a reference element (EF Al ) were higher than 1.5 for Eu, La, Zn, Th, Cs and As in which the highest EF Al value for As was higher than 10. This study showed that the HRI value of As in the tuna fish correlated positively with the EF Al value for the element in the marine sediment. (author)

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.

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

International Nuclear Information System (INIS)

Anton, M.P.; Gasco, C.; Sanchez-Cabeza, J.A.; Pujol, L.

1994-01-01

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.)

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Carbon dioxide storage in marine sediments - dissolution, transport and hydrate formation kinetics from high-pressure experiments

Science.gov (United States)

Bigalke, N. K.; Savy, J. P.; Pansegrau, M.; Aloisi, G.; Kossel, E.; Haeckel, M.

2009-12-01

By satisfying thermodynamic framework conditions for CO2 hydrate formation, pressures and temperatures of the deep marine environment are unique assets for sequestering CO2 in clathrates below the seabed. However, feasibility and safety of this storage option require an accurate knowledge of the rate constants governing the speed of physicochemical reactions following the injection of the liquefied gas into the sediments. High-pressure experiments designed to simulate the deep marine environment open the possibility to obtain the required parameters for a wide range of oceanic conditions. In an effort to constrain mass transfer coefficients and transport rates of CO2 in(to) the pore water of marine sediments first experiments were targeted at quantifying the rate of CO2 uptake by de-ionized water and seawater across a two-phase interface. The nature of the interface was controlled by selecting p and T to conditions within and outside the hydrate stability field (HSF) while considering both liquid and gaseous CO2. Concentration increase and hydrate growth were monitored by Raman spectroscopy. The experiments revealed anomalously fast transport rates of dissolved CO2 at conditions both inside and outside the HSF. While future experiments will further elucidate kinetics of CO2 transport and hydrate formation, these first results could have major significance to safety-related issues in the discussion of carbon storage in the marine environment.

Assessing bioavailability of DDT and metabolites in marine sediments using solid-phase microextraction with performance reference compounds.

Science.gov (United States)

Bao, Lian-Jun; Jia, Fang; Crago, J; Zeng, Eddy Y; Schlenk, D; Gan, Jay

2013-09-01

Solid-phase microextraction (SPME) has often been used to estimate the freely dissolved concentration (Cfree ) of organic contaminants in sediments. A significant limitation in the application of SPME for Cfree measurement is the requirement for attaining equilibrium partition, which is often difficult for strongly hydrophobic compounds such as DDT. A method was developed using SPME with stable isotope-labeled analogues as performance reference compounds (PRCs) to measure Cfree of DDT and metabolites (DDTs) in marine sediments. Six (13) C-labeled or deuterated PRCs were impregnated into polydimethylsiloxane (PDMS) fiber before use. Desorption of PRCs from PDMS fibers and absorption of DDTs from sediment were isotropic in a range of sediments evaluated ex situ under well-mixed conditions. When applied to a historically contaminated marine sediment from a Superfund site, the PRC-SPME method yielded Cfree values identical to those found by using a conventional equilibrium SPME approach (Eq-SPME), whereas the time for mixing was reduced from 9 d to only 9 h. The PRC-SPME method was further evaluated against bioaccumulation of DDTs by Neanthes arenaceodentata in the contaminated sediment with or without amendment of activated carbon or sand. Strong correlations were consistently found between the derived equilibrium concentrations on the fiber and lipid-normalized tissue residues for DDTs in the worms. Results from the present study clearly demonstrated the feasibility of coupling PRCs with SPME sampling to greatly shorten sampling time, thus affording much improved flexibility in the use of SPME for bioavailability evaluation. Copyright © 2013 SETAC.

Draft Genome Sequence of Antimicrobial-Producing Clostridium sp. JC272, Isolated from Marine Sediment

OpenAIRE

Tushar, L.; Sasi Jyothsna, T. S.; Sasikala, C.; Ramana, C. V.

2015-01-01

We announce the draft genome sequence of Clostridium sp. JC272, isolated from a sediment sample collected from marine habitats of Gujarat, India. Clostridium sp. JC272 is an obligate anaerobe and has the ability to produce antimicrobial compounds. The genome sequence indicates the strain?s capability of producing small peptides (microcins), which are potential novel antibiotics.

The ecological impacts of marine debris

NARCIS (Netherlands)

Rochman, Chelsea M.; Browne, Mark Anthony; Underwood, A.J.; Franeker, Van Jan A.; Thompson, Richard C.; Amaral-Zettler, Linda A.

2016-01-01

Anthropogenic debris contaminates marine habitats globally, leading to several perceived ecological impacts. Here, we critically and systematically review the literature regarding impacts of debris from several scientific fields to understand the weight of evidence regarding the ecological

Alternative procedure to determine radionuclide concentrations for marine sediment dating

International Nuclear Information System (INIS)

Palacios, D; Sajo-Bohus, L.; Alfonso, J.; Perez, K.; Trujillo, M.

2006-01-01

The development of an alternative method to prepare and to measure marine sediment samples for dating purpose using high resolution gamma spectrometry is given. To calculate the 137 Cs and the supported and unsupported 210 Pb concentrations, cylindrical tablets subjected to different pressures were analyzed. Mass attenuation coefficients (MAC) were determined by our variant of the transmission method, the Bragg law (using MACs provided by the web program XCOM) and the method of average composition of the analyzed sediment samples. The differences between obtained results are smaller than the experimental error (10%). The influence of pressure and sediment mass on the MAC, mechanical stability of the sample, and self-absorption corrections for different gamma energies is studied. Optimal dimensions of the tablets were determined from considerations on the infinite thickness, minimum detectable activity, precision of results, radiation self-absorption and geometric efficiency. Based on the differential peak absorption analysis, through a relative efficiency curve, a new method to evaluate the existence of radioactive equilibrium between 226 Ra, 222 Rn and its progeny is given. Experimental error of the proposed methodology is evaluated, as well as accuracy, precision and detection limit. With the use of developed methodology, the 210 Pb, 226 Ra and 137 Cs activities in recent sediment samples from near shore of the Orinoco River Delta were determined. The results were comparable with the obtained by two of the most used methods, while precision is improved and radiation self-absorption in sample container is avoided since sample encapsulation is not required. (Full Text)

Exploring the Impacts of Anthropogenic Disturbance on Seawater and Sediment Microbial Communities in Korean Coastal Waters Using Metagenomics Analysis

Directory of Open Access Journals (Sweden)

Nam-Il Won

2017-01-01

Full Text Available The coastal ecosystems are considered as one of the most dynamic and vulnerable environments under various anthropogenic developments and the effects of climate change. Variations in the composition and diversity of microbial communities may be a good indicator for determining whether the marine ecosystems are affected by complex forcing stressors. DNA sequence-based metagenomics has recently emerged as a promising tool for analyzing the structure and diversity of microbial communities based on environmental DNA (eDNA. However, few studies have so far been performed using this approach to assess the impacts of human activities on the microbial communities in marine systems. In this study, using metagenomic DNA sequencing (16S ribosomal RNA gene, we analyzed and compared seawater and sediment communities between sand mining and control (natural sites in southern coastal waters of Korea to assess whether anthropogenic activities have significantly affected the microbial communities. The sand mining sites harbored considerably lower levels of microbial diversities in the surface seawater community during spring compared with control sites. Moreover, the sand mining areas had distinct microbial taxonomic group compositions, particularly during spring season. The microbial groups detected solely in the sediment load/dredging areas (e.g., Marinobacter, Alcanivorax, Novosphingobium are known to be involved in degradation of toxic chemicals such as hydrocarbon, oil, and aromatic compounds, and they also contain potential pathogens. This study highlights the versatility of metagenomics in monitoring and diagnosing the impacts of human disturbance on the environmental health of marine ecosystems from eDNA.

The impact of electrogenic sulfide oxidation on elemental cycling and solute fluxes in coastal sediment

NARCIS (Netherlands)

Rao, A.M.F.; Malkin, S.Y.; Hidalgo-Martinez, S.; Meysman, Filip

2016-01-01

Filamentous sulfide oxidizing cable bacteria are capable of linking the oxidation of free sulfide in deep anoxic layers of marine sediments to the reduction of oxygen or nitrate in surface sediments by conducting electrons over centimeter-scale distances. Previous studies have shown that this newly

Biodegradation of dispersed marine fuel oil in sediment under engineered pre-spill application strategy

International Nuclear Information System (INIS)

Hua, J.

2006-01-01

Biodegradation of marine fuel oil was studied by monitoring changes in residual oil and populations of microorganisms in marine sediments. Biodegradation rates for dispersant and soap water were 2.09 and 2.27 g/kg per day, respectively, under pre-application strategy, suggesting that the strategy may promote MFO dispersion and provide with sufficient source of food. The effect of temperature on the effectiveness of pre-application strategy is particularly obvious for the growth of fungi and Pseudomonas maltophilia. The effect of pre-application of soap water on the tolerance of aerobic bacteria, Escherichia coli, and P. maltophilia, was gradually diminished within 25-33 days. (author)

Implications of S1 tephra findings in Dead Sea and Tayma palaeolake sediments for marine reservoir age estimation and palaeoclimate synchronisation

Science.gov (United States)

Neugebauer, Ina; Wulf, Sabine; Schwab, Markus J.; Serb, Johanna; Plessen, Birgit; Appelt, Oona; Brauer, Achim

2017-08-01

Here we report on the first findings of a cryptotephra in the Holocene lacustrine sediment records of the Dead Sea and Tayma palaeolake (NW Arabian Peninsula). The major element glass composition of this rhyolitic tephra is identical to the distal 'S1' tephra layer identified in the Yammoûneh palaeolake (Lebanon), in a marine sediment record from the SE Levantine basin and in the Sodmein Cave archaeological site in Egypt. The S1 tephra corresponds to the early Holocene 'Dikkartın' dome eruption of the Erciyes Dağ volcano in central Anatolia (Turkey) and has been dated in the marine record at 8830 ± 140 cal yr BP. We present new age estimates of the S1 tephra based on radiocarbon dating of terrestrial plant remains and pollen concentrates revealing ages of 8939 ± 83 cal yr BP in the Dead Sea sediments and 9041 ± 254 cal yr BP in Tayma. The precise date from the Dead Sea allows refining the early Holocene marine reservoir age in the SE Levantine Sea to ca. 320 ± 50 years. Synchronisation of marine and terrestrial palaeoclimate records in the eastern Mediterranean region using the S1 tephra further suggests a time-transgressive expansion of the early Holocene humid period.

Measurement and modeling of polychlorinated biphenyl bioaccumulation from sediment for the marine polychaete neanthes arenaceodentata and response to sorbent amendment

Science.gov (United States)

Janssen, E.M.-L.; Croteau, M.-N.; Luoma, S.N.; Luthy, R.G.

2010-01-01

Bioaccumulation rates of polychlorinated biphenyls (PCBs) for the marine polychaete Neanthes arenaceodentata were characterized, including PCB uptake rates from water and sediment, and the effect of sorbent amendment to the sediment on PCB bioavailability, organism growth, and lipid content. Physiological parameters were incorporated into a biodynamic model to predict contaminant uptake. The results indicate rapid PCB uptake from contaminated sediment and significant organism growth dilution during time-series exposure studies. PCB uptake from the aqueous phase accounted for less than 3% of the total uptake for this deposit-feeder. Proportional increase of gut residence time and assimilation efficiency as a consequence of the organism's growth was assessed by PCB uptake and a reactor theory model of gut architecture. Pulse-chase feeding and multilabeled stable isotope tracing techniques proved high sediment ingestion rates (i.e., 6?10 times of dry body weight per day) indicating that such deposit-feeders are promising biological indicators for sediment risk assessment. Activated carbon amendment reduced PCB uptake by 95% in laboratory experiments with no observed adverse growth effects on the marine polychaete. Biodynamic modeling explained the observed PCB body burdens for N. arenaceodentata, with and without sorbent amendment. ?? 2009 American Chemical Society.

A new marine sediment certified reference material (CRM) for the determination of persistent organic contaminants: IAEA-459.

Science.gov (United States)

Tolosa, Imma; Cassi, Roberto; Huertas, David

2018-04-11

A new marine sediment certified reference material (IAEA 459) with very low concentrations (μg kg -1 ) for a variety of persistent organic contaminants (POPs) listed by the Stockholm Convention, as well as other POPs and priority substances (PSs) listed in many environmental monitoring programs was developed by the IAEA. The sediment material was collected from the Ham River estuary in South Korea, and the assigned final values were derived from robust statistics on the results provided by selected laboratories which demonstrated technical and quality competence, following the guidance given in ISO Guide 35. The robust mean of the laboratory means was assigned as certified values, for those compounds where the assigned value was derived from at least five datasets and its relative expanded uncertainty was less than 40% of the assigned value (most of the values ranging from 8 to 20%). All the datasets were derived from at least two different analytical techniques which have allowed the assignment of certified concentrations for 22 polychlorinated biphenyl (PCB) congeners, 6 organochlorinated (OC) pesticides, 5 polybrominated diphenyl ethers (PBDEs), and 18 polycyclic aromatic hydrocarbon (PAHs). Mass fractions of compounds that did not fulfill the criteria of certification are considered information values, which include 29 PAHs, 11 PCBs, 16 OC pesticides, and 5 PBDEs. The extensive characterization and associated uncertainties at concentration levels close to the marine sediment quality guidelines will make CRM 459 a valuable matrix reference material for use in marine environmental monitoring programs.

Formation of Calcium Silicates during Ignition of Marine Sediments and its Implication on the State of Silica on the Sea Floor

International Nuclear Information System (INIS)

Duursma, E.K.; Bosch, C.J.; Eisma, D.

1976-01-01

Anomalies in the formation of calcium silicates in various marine sediment samples were observed on ignition at 800°C. The hypothesis is put forward that silica, originating from the land and from marine diatoms, undergoes a slow hydrolysis in the seabed and becomes more reactive. (author)

Properties of bricks produced from Greenlandic marine sediments

DEFF Research Database (Denmark)

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

2015-01-01

miniature bricks (54×54×60 mm3) of MS from Sisimiut. Brick pellets were prepared in order to determine an optimal composition and production method, based on investigations of the firing temperature and time,forming pressure, initial forming water content, and content of granite waste (CR). Miniature bricks......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...... were then prepared according to the optimal conditions and formed at a pressure of 20 MPa, fired at 1020 ºC for 3.5 days at the brickwork Wienerberger Tegl in Helsinge, Denmark. The durability properties such as porosity, water absorption, bulk density, linear shrinkage, and compressive strength (only...

Environmental impact assessment of oilfield upgrades in Bohai Sea

Science.gov (United States)

Chen, Ruihui; Xiong, Yanna; Li, Jiao; Li, Xianbo

2018-02-01

This paper designed 65 environmental monitoring sites to collect samples and analyze for better evaluating the environmental impact generated by cuttings, mud, produced water with oil and oil pollutions that produced during the upgrading in the Bohai Sea where the oil field 34-1 upgraded. Collecting samples include ocean water, marine life and sediments and test items involve PH, dissolved oxygen (DO), salinity, chemical oxygen demand (COD), phosphate, organic carbon, sulfide, inorganic nitrogen, petroleum, copper (Cu), lead (Pb), zinc (Zn), cadmium (Cd), total chromium (Cr), total mercury (Hg) and arsenic (As). Meanwhile sample sites collect and analyze the abundance and diversity of marine plants and elaborated the environmental impact caused by upgrading renovation project from the aspects of sea water, marine life and marine sediments. Through analysis and comparison we found that seawater quality conform the Ш seawater quality standards, the excessive rate of Cu is 10%, the average diversity index of marine life is 2.34 and evenness is 0.68. Influence range of marine sediments and pollutants of production is within 2.68km and basically has no serious impact in the surrounding sea area. It’s worth nothing that reconstruction project has the risk of oil spilling and protective measures must be prepared.

Early Cretaceous marine sediments of the Lower Saxony Basin. The Gildehaus Sandstone

Energy Technology Data Exchange (ETDEWEB)

Dellepiane, S.; Weiel, D. [Wintershall Holding GmbH, Barnstorf (Germany); Gerwert, D.; Mutterlose, J. [Bochum Univ. (Germany). Inst. fuer Geologie, Mineralogie und Geophysik

2013-08-01

During the Early Cretaceous (Berriasian - Aptian) the Lower Saxony Basin (LSB) formed the southernmost extension of the North Sea Basin. Sedimentation patterns of the LSB were controlled by divergent dextral shear movement causing differential subsidence related to early rifting in the North Sea. Up to 2000m of fine grained mudstones accumulated in the basin centre, while marginal marine, coarser grained siliciclastics were deposited along the western and southern margins of the LSB. The western marginal facies, outcropping along the Dutch-German border, is characterised by shallow marine sandstones of Valanginian - Hauterivian age. These units, which are separated by clay rich intervals, include the Bentheim Sdst., the Dichotomites Sdst., the Grenz Sdst., the Noricum Sdst. and the Gildehaus Sdst. These sandstones form a series of overall backstepping units, controlled by a main transgressive trend. Economically important are the Bentheim Sdst. and the Gildehaus Sdst., with a long oil producing history. The Bentheim Sdst. (early Valanginian) has been interpreted as an overall retrograding unit related to an incised valley infill with material mainly coming from the South. Tidal processes dominated the deposition of the Bentheim Sdst. The origin and genesis of the Gildehaus Sdst. (mid Hauterivian) is, however, less well understood. Here we present data from two wells drilled to the Gildehaus Sdst. (Emlichheim oil field) which provide evidence for a two fold subdivision of the unit. A well sorted massive quartz sandstone is followed by an interval composed of reworked coarse clastics of massflow origin. Micropalaeontological evidence suggests a fully marine, hemi-pelagic origin of the mud dominated matrix throughout the Gildehaus Sdst. These findings indicate a depositional environment quite different from that of the Bentheim Sdst. Short termed pulses of substantial input of clastic material from two different sources in the West to Southwest punctuated the overall

Microplastic pollution in the marine waters and sediments of Hong Kong.

Science.gov (United States)

Tsang, Y Y; Mak, C W; Liebich, C; Lam, S W; Sze, E T-P; Chan, K M

2017-02-15

The presence of plastic waste with a diameter of less than 5mm ("microplastics") in marine environments has prompted increasing concern in recent years, both locally and globally. We conducted seasonal surveys of microplastic pollution in the surface waters and sediments from Deep Bay, Tolo Harbor, Tsing Yi, and Victoria Harbor in Hong Kong between June 2015 and March 2016. The average concentrations of microplastics in local coastal waters and sediments respectively ranged from 51 to 27,909particles per 100m 3 and 49 to 279particles per kilogram. Microplastics of different shapes (mainly fragments, lines, fibers, and pellets) were identified as polypropylene, low-density polyethylene, high-density polyethylene, a blend of polypropylene and ethylene propylene, and styrene acrylonitrile by means of Attenuated Total Reflectance - Fourier Transform Infrared Spectroscopy. This is the first comprehensive study to assess the spatial and temporal variations of microplastic pollution in Hong Kong coastal regions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biogeochemical Insights into B-Vitamins in the Coastal Marine Sediments of San Pedro Basin, CA

Science.gov (United States)

Monteverde, D.; Berelson, W.; Baronas, J. J.; Sanudo-Wilhelmy, S. A.

2015-12-01

Coastal marine sediments support a high abundance of mircoorganisms which play key roles in the cycling of nutrients, trace metals, and carbon, yet little is known about many of the cofactors essential for their growth, such as the B-vitamins. The suite of B-vitamins (B1, B2, B6, B7, B12) are essential across all domains of life for both primary and secondary metabolism. Therefore, studying sediment concentrations of B-vitamins can provide a biochemical link between microbial processes and sediment geochemistry. Here we present B-vitamin pore water concentrations from suboxic sediment cores collected in September 2014 from San Pedro Basin, a silled, low oxygen, ~900 m deep coastal basin in the California Borderlands. We compare the B-vitamin concentrations (measured via LCMS) to a set of geochemical profiles including dissolved Fe (65-160 μM), dissolved Mn (30-300 nM), TCO2, solid phase organic carbon, and δ13C. Our results show high concentrations (0.8-3nM) of biotin (B7), commonly used for CO2 fixation as a cofactor in carboxylase enzymes. Thiamin (B1) concentrations were elevated (20-700nM), consistent with previous pore water measurements showing sediments could be a source of B1 to the ocean. Cobalamin (B12), a cofactor required for methyl transfers in methanogens, was also detected in pore waters (~4-40pM). The flavins (riboflavin [B2] and flavin mononucleotide[FMN]), molecules utilized in external electron transfer, showed a distinct increase with depth (10-90nM). Interestingly, the flavin profiles showed an inverse trend to dissolved Fe (Fe decreases with depth) providing a potential link to culture experiments which have shown extracellular flavin release to be a common trait in some metal reducers. As some of the first B-vitamin measurements made in marine sediments, these results illustrate the complex interaction between the microbial community and surrounding geochemical environment and provide exciting avenues for future research.

The Late Pliocene Eltanin Impact - Documentation From Sediment Core Analyses

Science.gov (United States)

Gersonde, R.; Kuhn, G.; Kyte, F. T.; Flores, J.; Becquey, S.

2002-12-01

The expeditions ANT-XII/4 (1995) and ANT-XVIII/5a (2001) of the RV POLARSTERN collected extensive bathymetric and seismic data sets as well as sediment cores from an area in the Bellingshausen Sea (eastern Pacific Southern Ocean) that allow the first comprehensive geoscientific documentation of an asteroid impact into a deep ocean (~ 5 km) basin, named the Eltanin impact. Impact deposits have now been recovered from a total of more than 20 sediment cores collected in an area covering about 80,000 km2. Combined biomagnetostratigraphic dating places the impact event into the earliest Matuyama Chron, a period of enhanced climate variability. Sediment texture analyses and studies of sediment composition including grain size and microfossil distribution reveal the pattern of impact-related sediment disturbance and the sedimentary processes immediately following the impact event. The pattern is complicated by the San Martin Seamounts (~57.5 S, 91 W), a large topographic elevation that rises up to 3000 m above the surrounding abyssal plain in the area affected by the Eltanin impact. The impact ripped up sediments as old as Eocene and probably Paleocene that have been redeposited in a chaotic assemblage. This is followed by a sequence sedimented from a turbulent flow at the sea floor, overprinted by fall-out of airborne meteoritic ejecta that settled trough the water column. Grain size distribution reveals the timing and interaction of the different sedimentary processes. The gathered estimate of ejecta mass deposited over the studied area, composed of shock-melted asteroidal matrial and unmelted meteorites including fragments up to 2.5 cm in diameter, point to an Eltanin asteroid larger than the 1 km in diameter size originally suggested as a minimum based on the ANT-XII/4 results. This places the energy released by the impact at the threshold of those considered to cause environmental disturbance at a global scale and it makes the impact a likely transport mechanism

Distributions of radionuclides among green alga (Ulva pertusa), sea water and marine sediment

International Nuclear Information System (INIS)

Nakamura, Ryoichi; Suzuki, Yuzuru; Ueda, Taishi

1976-01-01

Distributions of radionuclides ( 60 Co, 137 Cs, 95 Zr- 95 Nb and 106 Ru- 106 Rh) among green alga (Ulva pertusa), sea water and marine sediment were examined by radioisotope tracer experiment in order to estimate the influence of sediment on the accumulation of radionuclides by the alga. By the application of the compartment model to the experimental results, exponential formulas of distributions were obtained. Through comparison of the transfer coefficients of radionuclides calculated from the exponential formulas, the influence of the sediment on the accumulation of the radionuclides by the green alga was determined to be the largest for 60 Co, followed by 95 Zr,- 95 Nb, 106 Ru- 106 Rh and 137 Cs in this order. The activity ratios of 95 Zr- 95 Nb and 106 Ru- 106 Rh calculated from the transfer coefficients are larger for the alga than for the sediment, inversely those of 60 Co and 137 Cs show higher values for the sediment than for the alga. Especially, in the case of 60 Co, the activity ratio for the sediment is approximately 20 times greater than that for the alga. Biological half lives in green alga estimated from the transfer coefficients were 10 days for 60 Co, 7 days for 137 Cs, 26 days for 95 Zr- 95 Nb and 24 days for 95 Zr- 95 Nb and 24 days for 106 Ru- 106 Rh. (auth.)

The impact of the Fukushima nuclear accident on marine biota: Retrospective assessment of the first year and perspectives

International Nuclear Information System (INIS)

Vives i Batlle, Jordi; Aono, Tatsuo; Brown, Justin E.; Hosseini, Ali; Garnier-Laplace, Jacqueline; Sazykina, Tatiana; Steenhuisen, Frits; Strand, Per

2014-01-01

An international study under the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) was performed to assess radiological impact of the nuclear accident at the Fukushima-Daiichi Nuclear Power Station (FDNPS) on the marine environment. This work constitutes the first international assessment of this type, drawing upon methodologies that incorporate the most up-to-date radioecological models and knowledge. To quantify the radiological impact on marine wildlife, a suite of state-of-the-art approaches to assess exposures to Fukushima derived radionuclides of marine biota, including predictive dynamic transfer modelling, was applied to a comprehensive dataset consisting of over 500 sediment, 6000 seawater and 5000 biota data points representative of the geographically relevant area during the first year after the accident. The dataset covers the period from May 2011 to August 2012. The method used to evaluate the ecological impact consists of comparing dose (rates) to which living species of interest are exposed during a defined period to critical effects values arising from the literature. The assessed doses follow a highly variable pattern and generally do not seem to indicate the potential for effects. A possible exception of a transient nature is the relatively contaminated area in the vicinity of the discharge point, where effects on sensitive endpoints in individual plants and animals might have occurred in the weeks directly following the accident. However, impacts on population integrity would have been unlikely due to the short duration and the limited space area of the initially high exposures. Our understanding of the biological impact of radiation on chronically exposed plants and animals continues to evolve, and still needs to be improved through future studies in the FDNPS marine environment. - Highlights: • UNSCEAR assessment of the Fukushima accident impact on the marine environment. • The study covers the period from

The impact of the Fukushima nuclear accident on marine biota: Retrospective assessment of the first year and perspectives

Energy Technology Data Exchange (ETDEWEB)

Vives i Batlle, Jordi, E-mail: jordi.vives.i.batlle@sckcen.be [Biosphere Impact Studies Unit, Belgian Nuclear Research Centre SCK-CEN, Boeretang 200, 2400 Mol (Belgium); Aono, Tatsuo [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Brown, Justin E.; Hosseini, Ali [Norwegian Radiation Protection Authority, Grini næringspark 13, 1332 Østerås (Norway); CERAD Centre of Excellence, Grini næringspark 13, 1332 Østerås (Norway); Garnier-Laplace, Jacqueline [Institute for Radioprotection and Nuclear Safety, Department for research and expertise in environmental risks, PRP-ENV/SERIS, Cadarache, Building 159, 13115 Saint-Paul-Lez-Durance Cedex (France); Sazykina, Tatiana [State Institution Research and Production Association Typhoon, 4 Pobedy Str., Obninsk, Kaluga Region 249038 (Russian Federation); Steenhuisen, Frits [Arctic Centre, University of Groningen, Groningen (Netherlands); Strand, Per [Norwegian Radiation Protection Authority, Grini næringspark 13, 1332 Østerås (Norway); CERAD Centre of Excellence, Grini næringspark 13, 1332 Østerås (Norway)

2014-07-01

An international study under the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) was performed to assess radiological impact of the nuclear accident at the Fukushima-Daiichi Nuclear Power Station (FDNPS) on the marine environment. This work constitutes the first international assessment of this type, drawing upon methodologies that incorporate the most up-to-date radioecological models and knowledge. To quantify the radiological impact on marine wildlife, a suite of state-of-the-art approaches to assess exposures to Fukushima derived radionuclides of marine biota, including predictive dynamic transfer modelling, was applied to a comprehensive dataset consisting of over 500 sediment, 6000 seawater and 5000 biota data points representative of the geographically relevant area during the first year after the accident. The dataset covers the period from May 2011 to August 2012. The method used to evaluate the ecological impact consists of comparing dose (rates) to which living species of interest are exposed during a defined period to critical effects values arising from the literature. The assessed doses follow a highly variable pattern and generally do not seem to indicate the potential for effects. A possible exception of a transient nature is the relatively contaminated area in the vicinity of the discharge point, where effects on sensitive endpoints in individual plants and animals might have occurred in the weeks directly following the accident. However, impacts on population integrity would have been unlikely due to the short duration and the limited space area of the initially high exposures. Our understanding of the biological impact of radiation on chronically exposed plants and animals continues to evolve, and still needs to be improved through future studies in the FDNPS marine environment. - Highlights: • UNSCEAR assessment of the Fukushima accident impact on the marine environment. • The study covers the period from

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

2018-01-01

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 microporecontrolled 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

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

Rhodotorula portillonensis sp. nov., a basidiomycetous yeast isolated from Antarctic shallow-water marine sediment.

Science.gov (United States)

Laich, Federico; Vaca, Inmaculada; Chávez, Renato

2013-10-01

During the characterization of the mycobiota associated with shallow-water marine environments from Antarctic sea, a novel pink yeast species was isolated. Sequence analysis of the D1/D2 domain of the LSU rDNA gene and 5.8S-ITS regions revealed that the isolated yeast was closely related to Rhodotorula pallida CBS 320(T) and Rhodotorula benthica CBS 9124(T). On the basis of morphological, biochemical and physiological characterization and phylogenetic analyses, a novel basidiomycetous yeast species, Rhodotorula portillonensis sp. nov., is proposed. The type strain is Pi2(T) ( = CBS 12733(T)  = CECT 13081(T)) which was isolated from shallow-water marine sediment in Fildes Bay, King George Island, Antarctica.

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...

Estimating the in situ sediment-porewater distribution of PAHs and chlorinated aromatic hydrocarbons in anthropogenic impacted sediments

Energy Technology Data Exchange (ETDEWEB)

Hans Peter H. Arp; Gijs D. Breedveld; Gerard Cornelissen [Norwegian Geotechnical Institute (NGI), Oslo (Norway). Department of Environmental Engineering

2009-08-15

It has become increasingly apparent that the in situ sediment-porewater distribution behavior of organic compounds within anthropogenic impacted sediments is quite diverse, and challenging to generalize. Traditional models based on octanol-water partitioning generally overestimate native porewater concentrations, and modern approaches accounting for multiple carbon fractions, including black carbon, appear sediment specific. To assess the diversity of this sorption behavior, we collected all peer-reviewed total organic carbon (TOC)-normalized in situ sediment-porewater distribution coefficients, K{sub TOC}, for impacted sediments. This entailed several hundreds of data for PAHs, PCBs, PCDD/Fs, and chlorinated benzenes, covering a large variety of sediments, locations, and experimental methods. Compound-specific KTOC could range up to over 3 orders of magnitude. Output from various predictive models for individual carbonaceous phases found in impacted sediments, based on peer-reviewed polyparameter linear free energy relationships (PP-LFERs), Raoult's Law, and the SPARC online-calculator, were tested to see if any of the models could consistently predict literature K{sub TOC} values within a factor of 30 (i.e. about 1.5 orders of magnitude, or half the range of K{sub TOC} values). The Raoult's Law model and coal tar PP-LFER achieved the sought-after accuracy for all tested compound classes, and are recommended for general, regional-scale modeling purposes. As impacted sediment-porewater distribution models are unlikely to get more accurate than this, this review underpins that the only way to accurately obtain accurate porewater concentrations is to measure them directly, and not infer them from sediment concentrations. 86 refs., 2 figs., 3 tabs.

Climate change impacts on U.S. coastal and marine ecosystems

Science.gov (United States)

Scavia, Donald; Field, John C.; Boesch, Donald F.; Buddemeier, Robert W.; Burkett, Virginia; Cayan, Daniel R.; Fogarty, Michael; Harwell, Mark A.; Howarth, Robert W.; Mason, Curt; Reed, Denise J.; Royer, Thomas C.; Sallenger, Asbury H.; Titus, James G.

2002-01-01

Increases in concentrations of greenhouse gases projected for the 21st century are expected to lead to increased mean global air and ocean temperatures. The National Assessment of Potential Consequences of Climate Variability and Change (NAST 2001) was based on a series of regional and sector assessments. This paper is a summary of the coastal and marine resources sector review of potential impacts on shorelines, estuaries, coastal wetlands, coral reefs, and ocean margin ecosystems. The assessment considered the impacts of several key drivers of climate change: sea level change; alterations in precipitation patterns and subsequent delivery of freshwater, nutrients, and sediment; increased ocean temperature; alterations in circulation patterns; changes in frequency and intensity of coastal storms; and increased levels of atmospheric CO2. Increasing rates of sea-level rise and intensity and frequency of coastal storms and hurricanes over the next decades will increase threats to shorelines, wetlands, and coastal development. Estuarine productivity will change in response to alteration in the timing and amount of freshwater, nutrients, and sediment delivery. Higher water temperatures and changes in freshwater delivery will alter estuarine stratification, residence time, and eutrophication. Increased ocean temperatures are expected to increase coral bleaching and higher CO2 levels may reduce coral calcification, making it more difficult for corals to recover from other disturbances, and inhibiting poleward shifts. Ocean warming is expected to cause poleward shifts in the ranges of many other organisms, including commercial species, and these shifts may have secondary effects on their predators and prey. Although these potential impacts of climate change and variability will vary from system to system, it is important to recognize that they will be superimposed upon, and in many cases intensify, other ecosystem stresses (pollution, harvesting, habitat destruction

Estimation of sediment properties during benthic impact experiments

Digital Repository Service at National Institute of Oceanography (India)

Yamazaki, T.; Sharma, R

Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans...

Plastic litter in sediments from a marine area likely to become protected (Aeolian Archipelago's islands, Tyrrhenian sea).

Science.gov (United States)

Fastelli, Paolo; Blašković, Andrea; Bernardi, Giulia; Romeo, Teresa; Čižmek, Hrvoje; Andaloro, Franco; Russo, Giovanni F; Guerranti, Cristiana; Renzi, Monia

2016-12-15

This research aims to define for the first time levels and patterns of different litter groups (macro, meso and microplastics) in sediments from a marine area designed for the institution of a new marine protected area (Aeolian Archipelago, Italy). Microplastics resulted the principal group and found in all samples analyzed, with shape and colours variable between different sampling sites. MPs levels measured in this study are similar to values recorded in harbour sites and lower than reported in Adriatic Sea, while macroplastics levels are notably lower than in harbor sites. Sediment grain-size and island extent resulted not significant in determining levels and distribution of plastic debris among islands. In the future, following the establishment of the MPA in the study area, these basic data will be useful to check for potential protective effects on the levels and distribution of plastic debris. Copyright © 2016 Elsevier Ltd. All rights reserved.

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 (I geo ), 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.

Influences of marine sediment on the accumulation of radionuclides by green alga (Ulva pertusa)

International Nuclear Information System (INIS)

Nakamura, Ryoichi; Suzuki, Yuzuru; Ueda, Taiji

1975-01-01

Distribution of radionuclides ( 60 Co, 137 Cs, 95 Zr- 95 Nb and 106 Ru- 106 Rh) among green alga (Ulva pertusa), sea water and marine sediment were examined by radioisotope tracer experiment in order to estimate the influence of sediment on the accumulation of radionuclides by the alga. By the application of the compartment model to the experimental results, exponential formulas of distributions were obtained. Through comparison of the transfer coefficients of radionuclides calculated from the exponential formulas, the influence of the sediment on the accumulation of the radionuclides by the green alga was determined to be the largest for 60 Co, followed by 95 Zr- 95 Nb, 106 Ru- 106 Rh and 137 Cs in this order. The activity ratios of 95 Zr- 95 Nb and 106 Ru- 106 Rh calculated from the transfer coefficients are larger for the alga than for the sediment, inversely those of 60 Co and 137 Cs show higher values for the sediment than for the alga. Especially, in the case of 60 Co, the activity ratio for the sediment is approximately 20 times greater than that for the alga. Biological half lives in green alga estimated from the transfer coefficients were 10 days for 60 Co, 7 days for 137 Cs, 26 days for 95 Zr- 95 Nb and 24 days for 106 Ru- 106 Rh. (auth.)

Investigation of evaluation method for marine radiological impact during an accident

International Nuclear Information System (INIS)

2013-01-01

In 2012, JNES investigated the evaluation method, long-term seawater and marine deposition for release and diffusion to the ocean at the accident, and marine impact assessment code, in Japan and overseas. Also, the foreign regulations for marine radiological impact (direct release to ocean from the facilities and fallout on marine, etc.) were investigated. Furthermore, the index (e.g., intervention level) at emergency control in USA and Europe were investigated. (author)

Investigation of evaluation method for marine radiological impact during an accident

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-08-15

In 2012, JNES investigated the evaluation method, long-term seawater and marine deposition for release and diffusion to the ocean at the accident, and marine impact assessment code, in Japan and overseas. Also, the foreign regulations for marine radiological impact (direct release to ocean from the facilities and fallout on marine, etc.) were investigated. Furthermore, the index (e.g., intervention level) at emergency control in USA and Europe were investigated. (author)

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

Estimating suspended sediment yield, sedimentation controls and impacts in the Mellah Catchment of Northern Algeria

International Nuclear Information System (INIS)

Khanchoul, Kamel; Assassi Fella; Altschul, Robert

2009-01-01

This paper is an assessment of the suspended sediment yield in the Mellah Catchment of northern Algeria. We use discharge-sediment load relationships to explore the variability of water discharge and sediment load, and to investigate the impact of geomorphic factors disturbance on erosion and sedimentation. Suspended sediment load was analyzed in the Mellah Catchment (550 squre kms ) which was controlled by a gauging station to measure discharge and sediment transport. The relations between daily mean sediment concentration and daily mean water discharge were analyzed to develop sediment rating curves. For storms with no water samples, a sediment rating curve was developed. The technique involves stratification of data into discharge-based classes, the mean of which are used to fit a rating curve according to single flow data and season to provide various rating relationships. The mean annual sediment yield during the 24 years of the study period was 562 T km -2 in the Mellah Catchment. This drainage basin had high rainfall and runoff, the erosion was high. The high sediment yield in the Mellah basin could be explained by a high percentage of sparse grassland and cultivation developed on shallow marly silty-clayey soils with steep slopes often exceeding 12%. Almost all suspended sediment loads are transported during storm events that mainly occur in the winter and spring heavy and medium downpours. The scarceness of these events leads to a very large interseasonal variability of the wadi sediment fluxes. The negative impacts of this enhanced sediment mobility are directly felt in the western part of the basin which shows many mass movements, bank and gully erosion because cultivated areas are often bared during autumnal brief flash floods and furrowed downslope during the winter season. (author)

Multi-timescale sediment responses across a human impacted river-estuary system

Science.gov (United States)

Chen, Yining; Chen, Nengwang; Li, Yan; Hong, Huasheng

2018-05-01

Hydrological processes regulating sediment transport from land to sea have been widely studied. However, anthropogenic factors controlling the river flow-sediment regime and subsequent response of the estuary are still poorly understood. Here we conducted a multi-timescale analysis on flow and sediment discharges during the period 1967-2014 for the two tributaries of the Jiulong River in Southeast China. The long-term flow-sediment relationship remained linear in the North River throughout the period, while the linearity showed a remarkable change after 1995 in the West River, largely due to construction of dams and reservoirs in the upland watershed. Over short timescales, rainstorm events caused the changes of suspended sediment concentration (SSC) in the rivers. Regression analysis using synchronous SSC data in a wet season (2009) revealed a delayed response (average 5 days) of the estuary to river input, and a box-model analysis established a quantitative relationship to further describe the response of the estuary to the river sediment input over multiple timescales. The short-term response is determined by both the vertical SSC-salinity changes and the sediment trapping rate in the estuary. However, over the long term, the reduction of riverine sediment yield increased marine sediments trapped into the estuary. The results of this study indicate that human activities (e.g., dams) have substantially altered sediment delivery patterns and river-estuary interactions at multiple timescales.

Diversity of Microbial Communities and Quantitative Chemodiversity in Layers of Marine Sediment Cores from a Causeway (Kaichu-Doro) in Okinawa Island, Japan.

Science.gov (United States)

Soliman, Taha; Reimer, James D; Yang, Sung-Yin; Villar-Briones, Alejandro; Roy, Michael C; Jenke-Kodama, Holger

2017-01-01

Microbial community diversity and chemodiversity were investigated in marine sediments adjacent to the Okinawan "Kaichu-Doro" Causeway, which was constructed 46 years ago to connect a group of four islands (Henza-jima, Miyagi-jima, Ikei-jima, Hamahiga-jima) to the Okinawan main island. This causeway was not built on pilings, but by land reclamation; hence, it now acts as a long, thin peninsula. The construction of this causeway was previously shown to have influenced the surrounding marine ecosystem, causing ecosystem fragmentation and loss of water circulation. In this study, we collected sediment cores ( n = 10) from five paired sites in 1 m water depths. Each pair of sites consisted of one site each on the immediate north and south sides of the causeway. Originally the members of each pair were much closer to each other (microbial communities and chemical compounds to determine the correlation between chemodiversity and microbial communities among marine sediment cores and layers. Principal coordinate analyses (PCoA) of detected compounds and of bacterial and archaeal operational taxonomic units (OTUs) revealed that the north and south sides of the causeway are relatively isolated, with each side having unique microbial OTUs. Additionally, some bacterial families (e.g., Acidaminobacteraceae, Rhizobiaceae, and Xanthomonadaceae) were found only on the south side of Kaichu-Doro. Interestingly, we found that the relative abundance of OTUs for some microbial families increased from top to bottom, but this was reversed in some other families. We conclude that the causeway has altered microbial community composition and metabolite profiles in marine sediments.

Specific acyclic isoprenoids as biological markers of methanogenic bacteria in marine sediments.

Science.gov (United States)

Brassell, S C; Wardroper, A M; Thomson, I D; Maxwell, J R; Eglinton, G

1981-04-23

The widespread occurrence of extended hopanoids in sediments and petroleums illustrates the importance of bacterial lipid contributions to geological materials. In archaebacteria, however, hopanoids are absent; their role as structural components of biomembranes is fulfilled by acyclic isoprenoids. Recent studies of the lipid constituents of archaebacteria have greatly extended the range of acyclic isoprenoid skeletons known in organisms (Fig. 1). In particularly, isoprenoids with head-to-head linkages have been identified, and such compounds (for example, 3,7,11,15,18,22,26,30-octamethyldotriacontane, I) have been recognized in petroleum and as degradation products of Messel shale kerogen. Here we report the first recognition of 2,6,10,15,19-pentamethyleicosane (II), a known component of methanogens, in marine sediments of Recent to Cretaceous age (Table 1) and suggest that it and certain other acyclic isoprenoids may be used as biological markers for methanogens.

Intercomparison of radionuclide measurements in marine sediment sample IAEA-135

International Nuclear Information System (INIS)

Ballestra, S.; Gastaud, J.; Lopez, J.J.; Parsi, P.; Vas, D.

1993-08-01

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

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)

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.

Laboratory experiments on the transfer dynamics of plutonium from marine sediments to sea water and to marine organisms

International Nuclear Information System (INIS)

Mo, T.; Lowman, F.G.

1975-01-01

The leachability of 239 240 Pu from a fine contaminated calcareous sediment to aerated open sea water and to anoxic sea water was measured. The distribution coefficient for 239 240 Pu from sediment to sea water was 6.1 x 10 -5 for aerated water and 2.6 x 10 -6 for anoxic water. Experiments on the uptake of 239 240 Pu by the clams Donax denticulatus, and Lucina pectinata, were done in aquaria containing kilogram quantities of sediment from the Bravo Crater at Bikini Atoll. The concentration factor for 239 240 Pu by the soft parts of these clams was about 200. All the plutonium taken up in the soft parts was associated with the gill, mantle and siphon. No plutonium was detected in the adductor muscles or hepatopancreas. The smooth surfaces of the shells of the Donax did not show any detectable plutonium, but the rough shell surfaces of the Lucina concentrated plutonium by a factor of 1.10 x 10 4 over that in the sea water. Marine periphyton cultured on glass plates in an aquarium concentrated 239 240 Pu by a factor of about 7 x 10 3 over that in the sea water. (U.S.)

The geochemistry of marine sediments, island arc magma genesis, and crust-mantle recycling

International Nuclear Information System (INIS)

Ben Othman, D.; Paris-6 Univ., 75; White, W.M.; Cornell Univ., Ithaca, NY; Patchett, J.; Arizona Univ., Tucson

1989-01-01

To assess the role of sediment subduction and recycling in island arc magma genesis and mantle evolution, we have determined Sr, Nd, and Pb isotope ratios and the concentrations of K, Rb, Cs, Ba, Sr, U, Th, Pb and rare earth elements in 36 modern marine sediments, including Mn nodules, biogenic oozes, and pelagic and hemipelagic clays from the Pacific, Antlantic and Indian Oceans. Sr and Nd isotope ratios and the Sr/Nd concentration ratios in sediments are such that mixing between subducted sediment on the one hand and depleted mantle or subducted oceanic crust on the other can produce mixing arrays which may pass either through or outside of the oceanic basalt Sr-Nd isotope 'mantle array'. Thus whether isotope compositions of island arc volcanics (IAV) plot inside our outside of the mantle array is not a good indication of whether or not their sources contain a subducted sediment component. The presence of subducted sediment in the sources of IAV should lead to Cs/Rb and Pb/Ce ratios which are higher than those in oceanic basalts, and Ba/Rb ratios which may be either higher or lower than oceanic basalts. Simple mixing calculations suggest that as little as a percent or so sediment in island arc magma sources can account for the observed Cs/Rb, Pb/Ce, and Ba/Rb ratios in IAV. However, it does not appear that high Ba/La ratios and negative Ce anomalies in IAV are inherited from sediment in IAV magma sources. It is more likely these features reflect fractionation of alkalis and alkaline earths from rare earths during slab dehydration and metasomatism. Pb isotope ratios in sediments from the Warton Basin south of the Sunda Arc are collinear in 208 Pb/ 204 Pb- 207 Pb/ 204 Pb- 206 Bp/ 204 Pb space with volcanics from West Sunda, but not with volcanics from the East Sunda. This collinearity is consistent with the hypothesis that sediments similar to these are being subducted to the magma genesis zone of the West Sunda Arc. (orig./WB)

Uptake of PCBs contained in marine sediments by the green macroalga Ulva rigida.

Science.gov (United States)

Cheney, Donald; Rajic, Ljiljana; Sly, Elizabeth; Meric, Dogus; Sheahan, Thomas

2014-11-15

The uptake of PCBs contained in marine sediments by the green macroalga Ulva rigida was investigated in both laboratory and field experiments. Under laboratory conditions, total PCBs (tPCBs) uptake was significantly greater in live vs dead plants. The concentration of tPCB taken up in live plants was greatest in the first 24h (1580 μg kg(-1) dry weight), and then increased at a lower rate from day 2 to 14. Dead plants had a significantly lower tPCB concentration after 24h (609 μg kg(-1) dry weight) and lower uptake rate through day 14. Lesser chlorinated PCB congeners (below 123) made up the majority of PCBs taken up. Congener composition in both laboratory and field experiments was correlated to congener logKow value and sediment content. Field experiments showed that Ulva plants could concentrate PCBs to 3.9 mg kg(-1) in 24h. Thus, U. rigida is capable of removing PCBs in sediments at a rapid rate. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multi-elemental analysis of marine sediments of Manila Bay using x-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Rosales, Colleen Marciel Fontelera

2011-04-01

An analysis of the marine sediments of Manila Bay was done by employing X-ray fluorescence spectrometry. The general trends observed in sediments are increasing (Ca and Sr), decreasing (Zr), or constant (Cl, Na, S, K) with respect to depth, sometimes, no trend can be observed. These trends are further explained by correlations present among these elements, plus all the other elements. The two X RF data analysis methods Auto Quantify and AXIL were also compared on the basis of the correlation plot obtained. AutoQuantify gave clearer correlations; thus, results from this method were used for constructing correlation plots. Correlations using Microsoft Excel and Stat graphics Centurion X V show that there are naturally occurring [lithogenic (Si, Ti, Al, Mg, Rb, Zn and Fe), biogenic (Ca, Mg), and conservative (Na, Cl)] and non-naturally occurring [mostly anthropogenic, brought to the bodies of water by aeolian or fluvial input (heavy metals Pb-Cu-Zn and Ni-Cr)] correlation present in the sediments. Moreover, pairs of elements that may coexist in a source and not coexist in another (Cr and Mg, Cr and Ni) have also been observed. The heavy metal enrichment was attributed to the burning of fossil fuels, iron and steel manufacturing (present in Valenzuela-Bulacan area), ferry and fishing services and other industrialization activities present in Manila Bay. Marine organisms are affected by the presence of these heavy metals by means of bioaccumulations, and may later on affect humans because of trophic transfer and bio magnification. (author)

Concentration of Beryllium (Be) and Depleted Uranium (DU) in Marine Fauna and Sediment Samples from Illeginni and Boggerik Islands at Kwajalein Atoll

International Nuclear Information System (INIS)

Robison, W L; Hamilton, T F; Martinelli, R E; Kehl, S R; Lindman, T R

2005-01-01

Lawrence Livermore National Laboratory (LLNL) personnel have supported US Air Force (USAF) ballistic missile flight tests for about 15 years for Peacekeeper and Minuteman missiles launched at Vandenberg Air Force Base (VAFB). Associated re-entry vehicles (RV's) re-enter at Regan Test Site (RTS) at the US Army base at Kwajalein Atoll (USAKA) where LLNL has supported scoring, recovery operations for RV materials, and environmental assessments. As part of ongoing USAF ballistic missile flight test programs, LLNL is participating in an updated EA being written for flights originating at VFAB. Marine fauna and sediments (beach-sand samples) were collected by US Fish and Wildlife Service (USFWS), National Marine Fisheries Service (NMFS), and LLNL at Illeginni Island and Boggerik Island (serving as a control site) at Kwajalein Atoll. Data on the concentration of DU (hereafter, U) and Be in collected samples was requested by USFWS and NMFS to determine whether or not U and Be in RV's entering the Illeginni area are increasing U and Be concentrations in marine fauna and sediments. LLNL agreed to do the analyses for U and Be in support of the EA process and provide a report of the results. There is no statistically significant difference in the concentration of U and Be in six species of marine fauna from Illeginni and Boggerik Islands (p - 0.14 for U and p = 0.34 for Be). Thus, there is no evidence that there has been any increase in U and Be concentrations in marine fauna as a result of the missile flight test program. Concentration of U in beach sand at Illeginni is the same as soil and beach sand in the rest of the Marshall Islands and again reflects an insignificant impact from the flight test program. Beach sand from Illeginni has a mean concentration of Be higher than that from the control site, Boggeik Island. Seven of 21 samples from Ileginni had detectable Be. Four samples had a concentration of Be ranging from 4 to 7 ng g -1 (4 to 7 parts per billion (ppb)), one

Estimating sediment accumulation rates in Manila Bay, a marine pollution hot spot in the Seas of East Asia.

Science.gov (United States)

Sta Maria, E J; Siringan, F P; Bulos, A dM; Sombrito, E Z

2009-01-01

The GEF/UNDP/IMO/PEMSEA project identifies Manila Bay as among the marine pollution hot spots in the Seas of East Asia. (210)Pb dating of its sediment can provide a historical perspective of its pollution loading. However, the validity of (210)Pb dating in a complex dynamic coastal system of Manila Bay may come into question. Land-based sediment input can be high and physical and biological processes can possibly disturb the sediment layers. In this report, the (210)Pb profiles of sediment cores from different parts of the bay are presented. The linear sedimentation rates are shown to be higher in the recent past and are also variable across the bay. The largest change in sedimentation rate, coincided with the occurrence of a volcanic eruption in 1991 and is shown by applying a variant of the CIC model in sedimentation rate calculations. The data suggest that (210)Pb dating can be useful in estimating relative magnitudes of sedimentation rates, even in a complex dynamic coastal system like Manila Bay.

Environmental impact of the minero-metallurgic industry on the marine ecosystem in Moa, Cuba

International Nuclear Information System (INIS)

Martinez Canals, M.; Pedro Garcia, L.

1999-01-01

One of the biggest nickel mineral deposits of the world is located in Moa; therefore two plants are installed for the extraction of this metal in the region, and another is in its construction phase. During the technological processes, residuals that contain great quantity of metallic elements, and high acidity level are discharged into the environment. The objectives of this research were to establish the levels of pollution of eleven metals, Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn in the superficial bottom sediments, sea water and organisms of the marine aquatorium (green and white sea urchins, blue crabs, oysters and mangrove leaves). The dynamics of pollution in superficial sediments was also determined in the course of a 9-year study. As complementary analyses, pH and salinity were determined for the supradjacent water to the marine bottom, as well as the content of organic carbon, and granulometry of the sediment

Comparison of estuarine sediment record with modelled rates of sediment supply from a western European catchment since 1500

Science.gov (United States)

Poirier, Clément; Poitevin, Cyril; Chaumillon, Éric

2016-09-01

Marine and estuarine sediment records reporting impacts of historical land use changes exist worldwide, but they are rarely supported by direct quantified evidence of changes in denudation rates on the related catchments. Here we implement a spatially-resolved RUSLE soil erosion model on the 10 000 km2 Charente catchment (France), supplied with realistic scenarios of land-cover and climate changes since 1500, and compare the results to a 14C-dated estuarine sediment record. Despite approximations, the model correctly predicts present-day Charente river sediment load. Back-cast modelling suggests that the Charente catchment is an interesting case where the sediment supply did not change despite increase in soil erosion resulting from 18th-century deforestation because it was mitigated by drier climate during the same period. Silt-sand alternations evidenced in the sediment record were correlated with sub-decadal rainfall variability.

Biogeochemical and molecular signatures of anaerobic methane oxidation in a marine sediment.

Science.gov (United States)

Thomsen, T R; Finster, K; Ramsing, N B

2001-04-01

Anaerobic methane oxidation was investigated in 6-m-long cores of marine sediment from Aarhus Bay, Denmark. Measured concentration profiles for methane and sulfate, as well as in situ rates determined with isotope tracers, indicated that there was a narrow zone of anaerobic methane oxidation about 150 cm below the sediment surface. Methane could account for 52% of the electron donor requirement for the peak sulfate reduction rate detected in the sulfate-methane transition zone. Molecular signatures of organisms present in the transition zone were detected by using selective PCR primers for sulfate-reducing bacteria and for Archaea. One primer pair amplified the dissimilatory sulfite reductase (DSR) gene of sulfate-reducing bacteria, whereas another primer (ANME) was designed to amplify archaeal sequences found in a recent study of sediments from the Eel River Basin, as these bacteria have been suggested to be anaerobic methane oxidizers (K. U. Hinrichs, J. M. Hayes, S. P. Sylva, P. G. Brewer, and E. F. DeLong, Nature 398:802-805, 1999). Amplification with the primer pairs produced more amplificate of both target genes with samples from the sulfate-methane transition zone than with samples from the surrounding sediment. Phylogenetic analysis of the DSR gene sequences retrieved from the transition zone revealed that they all belonged to a novel deeply branching lineage of diverse DSR gene sequences not related to any previously described DSR gene sequence. In contrast, DSR gene sequences found in the top sediment were related to environmental sequences from other estuarine sediments and to sequences of members of the genera Desulfonema, Desulfococcus, and Desulfosarcina. Phylogenetic analysis of 16S rRNA sequences obtained with the primers targeting the archaeal group of possible anaerobic methane oxidizers revealed two clusters of ANME sequences, both of which were affiliated with sequences from the Eel River Basin.

Microbial diversity in methane hydrate-bearing deep marine sediments core preserved in the original pressure.

Science.gov (United States)

Takahashi, Y.; Hata, T.; Nishida, H.

2017-12-01

In normal coring of deep marine sediments, the sampled cores are exposed to the pressure of the atmosphere, which results in dissociation of gas-hydrates and might change microbial diversity. In this study, we analyzed microbial composition in methane hydrate-bearing sediment core sampled and preserved by Hybrid-PCS (Pressure Coring System). We sliced core into three layers; (i) outside layer, which were most affected by drilling fluids, (ii) middle layer, and (iii) inner layer, which were expected to be most preserved as the original state. From each layer, we directly extracted DNA, and amplified V3-V4 region of 16S rRNA gene. We determined at least 5000 of nucleotide sequences of the partial 16S rDNA from each layer by Miseq (Illumina). In the all layers, facultative anaerobes, which can grow with or without oxygen because they can metabolize energy aerobically or anaerobically, were detected as majority. However, the genera which are often detected anaerobic environment is abundant in the inner layer compared to the outside layer, indicating that condition of drilling and preservation affect the microbial composition in the deep marine sediment core. This study was conducted as a part of the activity of the Research Consortium for Methane Hydrate Resources in Japan [MH21 consortium], and supported by JOGMEC (Japan Oil, Gas and Metals National Corporation). The sample was provided by AIST (National Institute of Advanced Industrial Science and Technology).

226Ra-210Pb-210Po Levels in Marine Biota and Surface Coastal Sediments from the Red Sea, Sudan

International Nuclear Information System (INIS)

Sirelkhatim, D.A.; Sam, A.K.; Hassona, R.K.

2003-01-01

This paper presents data on 226 Ra, 210 Pb and 210 Po activity concentration levels in multicellular marine algae, molluscs, coral as well as in surface marine sediments collected from the shallower waters of the fringing reefs area extending towards north and south (Flamingo bay) of Port sudan harbour. The analyses were performed adopting a simple time efficient method combining alpha-spectrometry, liquid scintillation and Cerenkov counting technique. Generally speaking, surface sediments from this coastal region are poor in their radioactivity content in contrast to similar data reported from different coastal areas around the globe. There is surface enrichment of 210 Pb and 210 Po with respect to their progenitor 226 Ra as it is evident from the activity ratios of 210 Pb/ 226 Ra (3.03±1.79) and 210 Po/ 226 Ra (2.23±1.56). Among marine plants and animals investigated, the green algae species, Halimeda, and coral species, Favites, show substantial concentration of radium at 8.2 Bq/KXg and 21.9 Bq/KXg dry weight, respectively

Some trace elements in the waters, marine organisms and sediments of the Adriatic by neutron activation analysis

International Nuclear Information System (INIS)

Kosta, L.; Ravnik, V.; Byrne, A.R.; Dermelj, M.; Stirn, J.

1978-01-01

A number of investigations of trace elements in the waters, organisms and sediments of the Adriatic, using neutron activation analysis with radiochemical separations are reported. These include studies of Hg in mussels from the Northern Adriatic, of Hg and Se in edible animals from the Rijeka region, and of seven elements (As, Cd, Cu, Hg, Mn, Se and Zn) in marine invertebrates from the Slovene coast. Additionally, plankton, sediment cores and water samples were taken from a grid of stations covering the whole Adriatic and analyzed for 6 to 11 of the trace elements As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Sb and Zn (Hg only in water). Generally, levels found were not indicative of pollution as compared with oceanic samples, but some evidence of locally increased levels was found, especially for Hg. The levels of eleven trace elements in three marine Intercomparison samples prepared by the IAEA Monaco Laboratory are also presented. (T.G.)

Aspects regarding environmental impact of oil marine platforms from Black sea coast - Romanian area

International Nuclear Information System (INIS)

Szabo, N.

2005-01-01

Full text : As a result of investigations conducted by R.A.PETROM - PETROMAR Constanta subsidiary, reserves of oil and gas in geological structures LEBADA, EOCEN - LEBADA and SINOE from romanian sector of Black Sea Continental Platform, have been discovered. These reserves are exploited by marine platforms and ways of oil transportation to the shore are submarine pipe-lines and ships. To assess environmental impact of oil transportation, studies covered following steps; Characterization of the present status of environmental factors, in the range of pipe-lines and ships; Marine water characterization: salinity, ionic composition, dissolved gases, organic depositions on metallic bodies; Marine bicenosys: phytoplankton and zooplankton characteristics, phytobenthos and zoobenthos communities, marine ichtyofauna, marine mammals. Marine resources available for exploitation; Total radioactivity analysis results; Marine water hydrocarbons analysis results; Present pollution sources in the area; Air quality in oil marine platforms area and shore area; Potential pollution sources and pollutants resulted from oil products transport between marine platforms and shore; Sources and emissions in air; Sources and emissions in marine environment; Aspects regarding waste management; Environmental impact of oil products transport between marine platforms and shore; Impact on the air quality and marine environment of oil marine platforms activities; Assessment of environmental impact on atmosphere generated by the oil products transport between marine platforms and shore; Impact on the marine environment of oil transport ships; Effects of oil fractions on marine organisms; Acute effects of oil pollution on marine communities; Risks of causing major environmental impact accidents/failures on marine platforms PETROMAR; Chronic effects of low oil concentrations;Marine environment recovery potential after discharges accidents

Tracing time in the ocean: Unraveling depositional and preservational timescales using compound-specific radiocarbon analysis of biomarkers from marine sediments

OpenAIRE

Kusch, Stephanie

2010-01-01

Carbon cycle dynamics between the different inorganic and organic carbon pools play an important role in controlling the atmospheric chemical composition, thus, regulating the Earth’s climate. Atmospheric CO2 is fixed into biomass by photosynthesis of terrestrial and marine primary producers. Until final burial in marine sediments, the biologically fixed carbon that escapes remineralisation undergoes exchange between various active carbon reservoirs. Until now, the timescales o...

Recreational impacts on the fauna of Australian coastal marine ecosystems.

Science.gov (United States)

Hardiman, Nigel; Burgin, Shelley

2010-11-01

This paper reviews recent research into the ecological impacts of recreation and tourism on coastal marine fauna in Australia. Despite the high and growing importance of water-based recreation to the Australian economy, and the known fragility of many Australian ecosystems, there has been relatively limited research into the effects of marine tourism and recreation, infrastructure and activities, on aquatic resources. In this paper we have reviewed the ecological impacts on fauna that are caused by outdoor recreation (including tourism) in Australian coastal marine ecosystems. We predict that the single most potentially severe impact of recreation may be the introduction and/or dispersal of non-indigenous species of marine organisms by recreational vessels. Such introductions, together with other impacts due to human activities have the potential to increasingly degrade recreation destinations. In response, governments have introduced a wide range of legislative tools (e.g., impact assessment, protected area reservation) to manage the recreational industry. It would appear, however, that these instruments are not always appropriately applied. Copyright 2010 Elsevier Ltd. All rights reserved.

A New Sensitive GC-MS-based Method for Analysis of Dipicolinic Acid and Quantifying Bacterial Endospores in Deep Marine Subsurface Sediment

Science.gov (United States)

Fang, J.

2015-12-01

Marine sediments cover more than two-thirds of the Earth's surface and represent a major part of the deep biosphere. Microbial cells and microbial activity appear to be widespread in these sediments. Recently, we reported the isolation of gram-positive anaerobic spore-forming piezophilic bacteria and detection of bacterial endospores in marine subsurface sediment from the Shimokita coalbed, Japan. However, the modern molecular microbiological methods (e.g., DNA-based microbial detection techniques) cannot detect bacterial endospore, because endospores are impermeable and are not stained by fluorescence DNA dyes or by ribosomal RNA staining techniques such as catalysed reporter deposition fluorescence in situ hybridization. Thus, the total microbial cell abundance in the deep biosphere may has been globally underestimated. This emphasizes the need for a new cultivation independent approach for the quantification of bacterial endospores in the deep subsurface. Dipicolinic acid (DPA, pyridine-2,6-dicarboxylic acid) is a universal and specific component of bacterial endospores, representing 5-15wt% of the dry spore, and therefore is a useful indicator and quantifier of bacterial endospores and permits to estimate total spore numbers in the subsurface biosphere. We developed a sensitive analytical method to quantify DPA content in environmental samples using gas chromatography-mass spectrometry. The method is sensitive and more convenient in use than other traditional methods. We applied this method to analyzing sediment samples from the South China Sea (obtained from IODP Exp. 349) to determine the abundance of spore-forming bacteria in the deep marine subsurface sediment. Our results suggest that gram-positive, endospore-forming bacteria may be the "unseen majority" in the deep biosphere.

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

(bacteriochlorophyll a). Infrared scalar irradiance reached 200% of incident light intensity at 0.0-0.3-mm depth and IR penetration was independent of the development of a cyanobacterial surface film. At high incident light intensity, 740 muEinst m-2 s-1, the photosynthetic efficiency at 1.0-mm depth was 10-fold...... higher than in the uppermost 0.0-0.6 mm of the sediment. The lower boundary of the euphotic zone (detectable gross photosynthesis) was at a mean light level of greater-than-or-equal-to 7.5 muEinst m-2 s-1.......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...

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.

Isolation of naphthalene-degrading bacteria from tropical marine sediments

International Nuclear Information System (INIS)

Zhuang, W.-Q.; Tay, J.-H.; Maszenan, A.M.; Tay, S.T.-L.

2003-01-01

Oil pollution is a major environmental concern in many countries, and this has led to a concerted effort in studying the feasibility of using oil-degrading bacteria for bioremediation. Although many oil-degrading bacteria have been isolated from different environments, environmental conditions can impose a selection pressure on the types of bacteria that can reside in a particular environment. This study reports the successful isolation of two indigenous naphthalene-degrading bacteria from oil-contaminated tropical marine sediments by enrichment culture. Strains MN-005 and MN-006 were characterized using an extensive range of biochemical tests. The 16S ribosomal deoxyribonucleic acid (rDNA) sequence analysis was also performed for the two strains. Their naphthalene degradation capabilities were determined using gas chromatography and DAPI counting of bacterial cells. Strains MN-005 and MN-006 are phenotypically and phylogenetically different from each other, and belong to the genera Staphylococcus and Micrococcus, respectively. Strains MN-005 and MN-006 has maximal specific growth rates (μ max ) of 0.082±0.008 and 0.30±0.02 per hour, respectively, and half-saturation constants (K s ) of 0.79±0.10 and 2.52±0.32 mg per litre, respectively. These physiological and growth studies are useful in assessing the potential of these indigenous isolates for in situ or ex situ naphthalene pollutant bioremediation in tropical marine environments. (author)

8. Danish meeting for marine researchers

International Nuclear Information System (INIS)

1994-01-01

The publication comprises the programme for the 8th Danish meeting for marine researchers held in Odense (Denmark) on January 25th - 27th, 1994, and the abstracts of the papers that were presented at that meeting. Subjects covered are marine biology, sediments and sedimentation, fish, fishing and fishing regulation, marine processes and the monitoring of Danish straits. (AB)

The 10. Danish marine research meeting

International Nuclear Information System (INIS)

1998-01-01

The publication comprises the programme for the 10th Danish meeting for marine researchers held in Hirtshals (Denmark) on January 21 - 27, 1998, and the abstracts of the papers that were presented at that meeting. Subjects covered are marine biology, sediments and sedimentation, fish, fishing and fishing regulations, marine processes and the monitoring of Danish straits. (EG)

Cable Bacteria in Freshwater Sediments

DEFF Research Database (Denmark)

Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus

2015-01-01

In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

Contamination in sediments, bivalves and sponges of McMurdo Sound, Antarctica

Energy Technology Data Exchange (ETDEWEB)

Negri, Andrew [Australian Institute of Marine Science, PMB 3, Townsville, Qld (Australia)]. E-mail: a.negri@aims.gov.au; Burns, Kathryn [Australian Institute of Marine Science, PMB 3, Townsville, Qld (Australia); Boyle, Steve [Australian Institute of Marine Science, PMB 3, Townsville, Qld (Australia); Brinkman, Diane [Australian Institute of Marine Science, PMB 3, Townsville, Qld (Australia); Webster, Nicole [Australian Institute of Marine Science, PMB 3, Townsville, Qld (Australia); Biological Sciences, University of Canterbury, Christchurch (New Zealand)

2006-10-15

This study examined the concentrations of total hydrocarbons (THC), polychlorinated biphenyls (PCB), polyaromatic hydrocarbons (PAH), and trace metals (Cu, Zn, Cd, Pb, Hg and As) in marine sediments off Scott Base (NZ) and compared them with sediments near the highly polluted McMurdo Station (US) as well as less impacted sites including Turtle Rock and Cape Evans. The Antarctic mollusc, Laternula elliptica and three common sponge species were also analysed for trace metals. The mean THC concentration in sediments from Scott Base was 3 fold higher than the pristine site, Turtle Rock, but 10 fold lower than samples from McMurdo Station. McMurdo Station sediments also contained the highest concentrations of PAHs, PCBs and the trace metals, Cu, Zn, Pb, Cd and Hg. Copper was significantly higher in bivalves from McMurdo Station than other sites. Trace metal concentrations in sponges were generally consistent within sites but no spatial patterns were apparent. - Analyses of Antarctic marine sediments, bivalves and sponges revealed strong PAH, PCB and trace metal gradients in McMurdo Sound.

Contamination in sediments, bivalves and sponges of McMurdo Sound, Antarctica

International Nuclear Information System (INIS)

Negri, Andrew; Burns, Kathryn; Boyle, Steve; Brinkman, Diane; Webster, Nicole

2006-01-01

This study examined the concentrations of total hydrocarbons (THC), polychlorinated biphenyls (PCB), polyaromatic hydrocarbons (PAH), and trace metals (Cu, Zn, Cd, Pb, Hg and As) in marine sediments off Scott Base (NZ) and compared them with sediments near the highly polluted McMurdo Station (US) as well as less impacted sites including Turtle Rock and Cape Evans. The Antarctic mollusc, Laternula elliptica and three common sponge species were also analysed for trace metals. The mean THC concentration in sediments from Scott Base was 3 fold higher than the pristine site, Turtle Rock, but 10 fold lower than samples from McMurdo Station. McMurdo Station sediments also contained the highest concentrations of PAHs, PCBs and the trace metals, Cu, Zn, Pb, Cd and Hg. Copper was significantly higher in bivalves from McMurdo Station than other sites. Trace metal concentrations in sponges were generally consistent within sites but no spatial patterns were apparent. - Analyses of Antarctic marine sediments, bivalves and sponges revealed strong PAH, PCB and trace metal gradients in McMurdo Sound

Study of radionuclide and element characterization of Angola marine sediment using low background gamma spectrometry and instrumental neutron activation analysis techniques

International Nuclear Information System (INIS)

Teixeira, M.C.P.; Vuong Huu Tan; Truong Y; Ho Manh Dung; Le Nhu Sieu; Cao Dong Vu; Nguyen Thanh Binh

2007-01-01

The concentrations of radionuclides and chemical elements in Angola marine sediment samples were determined by using low background gamma (LBG) spectrometry and instrumental neutron activation analysis (INAA). The combination of radionuclide and elemental concentration values yielded synergy in the validation of analytical data and identification of sediment sources modeled by multivariate factor analysis. Varimax rotation factor analysis based on the elemental concentrations revealed five sources contributed to the sediment composition, i.e. crustal, sea-salt, industrial, coal-related and Se-related sources. (author)

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

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

Impact of mussel bioengineering on fine-grained sediment dynamics in a coastal lagoon: A numerical modelling investigation

Science.gov (United States)

Forsberg, Pernille L.; Lumborg, Ulrik; Bundgaard, Klavs; Ernstsen, Verner B.

2017-12-01

Rødsand lagoon in southeast Denmark is a non-tidal coastal lagoon. It is home to a wide range of marine flora and fauna and part of the Natura 2000 network. An increase in turbidity through elevated levels of suspended sediment concentration (SSC) within the lagoon may affect the ecosystem health due to reduced light penetration. Increasing SSC levels within Rødsand lagoon could be caused by increasing storm intensity or by a sediment spill from dredging activities west of the lagoon in relation to the planned construction of the Fehmarnbelt fixed link between Denmark and Germany. The aim of the study was to investigate the impact of a mussel reef on sediment import and SSC in a semi-enclosed lagoon through the development of a bioengineering modelling application that makes it possible to include the filtrating effect of mussels in a numerical model of the lagoonal system. The numerical implementation of an exterior mussel reef generated a reduction in the SSC in the vicinity of the reef, through the adjacent inlet and in the western part of the lagoon. The mussel reef reduced the sediment import to Rødsand lagoon by 13-22% and reduced the SSC within Rødsand lagoon by 5-9% depending on the filtration rate and the reef length. The results suggest that the implementation of a mussel reef has the potential to relieve the pressure of increasing turbidity levels within a semi-enclosed lagoonal system. However, further assessment and development of the bioengineering application and resulting ecosystem impacts are necessary prior to actual implementation.

Larval development ratio test with the calanoid copepod Acartia tonsa as a new bioassay to assess marine sediment quality.

Science.gov (United States)

Buttino, Isabella; Vitiello, Valentina; Macchia, Simona; Scuderi, Alice; Pellegrini, David

2018-03-01

The copepod Acartia tonsa was used as a model species to assess marine sediment quality. Acute and chronic bioassays, such as larval development ratio (LDR) and different end-points were evaluated. As a pelagic species, A. tonsa is mainly exposed to water-soluble toxicants and bioassays are commonly performed in seawater. However, an interaction among A. tonsa eggs and the first larval stages with marine sediments might occur in shallow water environments. Here we tested two different LDR protocols by incubating A. tonsa eggs in elutriates and sediments coming from two areas located in Tuscany Region (Central Italy): Livorno harbour and Viareggio coast. The end-points analyzed were larval mortality (LM) and development inhibition (DI) expressed as the percentage of copepods that completed the metamorphosis from nauplius to copepodite. Aims of this study were: i) to verify the suitability of A. tonsa copepod for the bioassay with sediment and ii) to compare the sensitivity of A. tonsa exposed to different matrices, such as water and sediment. A preliminary acute test was also performed. Acute tests showed the highest toxicity of Livorno's samples (two out of three) compared to Viareggio samples, for which no effect was observed. On the contrary, LDR tests with sediments and elutriates revealed some toxic effects also for Viareggio's samples. Results were discussed with regards to the chemical characterization of the samples. Our results indicated that different end-points were affected in A. tonsa, depending on the matrices to which the copepods were exposed and on the test used. Bioassays with elutriates and sediments are suggested and LDR test could help decision-makers to identify a more appropriate management of dredging materials. Copyright © 2017 Elsevier Inc. All rights reserved.

Rare earth elements determination and distribution patterns in sediments of a polluted marine environment by instrumental neutron activation analysis

International Nuclear Information System (INIS)

Yusof, A.M.

2001-01-01

Results obtained from the analysis of sediment core samples taken from a fairly polluted marine environment were analyzed for the REE contents to determine the concentrations of La, Ce, Sm, Eu, Tb, Dy and Yb using instrumental neutron activation analysis. Core samples were divided into strata of between 2 to 3 cm intervals and prepared in the powdered form before irradiating them in a neutron flux of about 5.0 x 10 12 n x cm -2 x s -1 in a Triga Mark II reactor. Down-core concentration profiles of La, Ce, Sm, Eu, Tb, Dy and Yb in 3 core sediments from three sites are obtained. The shale-normalized REE pattern from each site was examined and later used to explain the history of sedimentation by natural processes such as shoreline erosion and weathering products deposited on the seabed and furnishing some baseline data and/or pollution trend occurring within the study area. The shale-normalized REE patterns also showed that LREE in the sediment samples exhibit enrichment relative to HREE particularly, La and Sm showing enrichment compared to the ratios in shale. REE concentrations of 124 μg/g at the surface of sediment collected at two of the three sites were found to decrease to 58 and 95 μg/g, respectively. This was of particular interest when it is used to explain the anomalies occurring in the marine sediment as a result of geochemical processes over a long period of time. Changes in concentrations from surface to bottom of the sediments ratioed to Sm concentrations and the correlation between concentrations of Sm and these elements were also investigated and correlation coefficients were calculated for all REEs and sites. Validation of the method used was done using a Soil-7 SRM. (author)

Modeling sediment transport in Qatar: Application for coastal development planning.

Science.gov (United States)

Yousif, Ruqaiya; Warren, Christopher; Ben-Hamadou, Radhouan; Husrevoglu, Sinan

2018-03-01

Hydrodynamics and sediment transport are key physical processes contributing to habitat structure within the marine environment. Coastal development that results in the alteration of these processes (e.g., changing water flushing and/or sedimentation rates) can have detrimental impacts on sensitive systems. This is a current, relevant issue in Qatar as its coastal regions continue to be developed, not only around the capital of Doha, but in many areas around this Arabian Gulf peninsula. The northeastern Qatari coast is comprised of diverse and sensitive flora and fauna such as seagrass and macroalgae meadows, coral reefs and patches, turtles, and dugongs that tolerate harsh environmental conditions. In the near future, this area may see a rise in anthropogenic activity in the form of coastal development projects. These projects will add to existing natural stresses, such as high temperature, high salinity, and low rates of precipitation. Consequently, there is a need to characterize this area and assess the potential impacts that these anthropogenic activities may have on the region. In the present study, a novel sediment transport model is described and used to demonstrate the potential impact of altering hydrodynamics and subsequent sediment transport along the northeastern Qatar nearshore marine environment. The developed models will be tested using potential scenarios of future anthropogenic activities forecasted to take place in the area. The results will show the effects on water and sediment behavior and provide a scientific approach for key stakeholders to make decisions with respect to the management of the considered coastal zone. Furthermore, it provides a tool and framework that can be utilized in environmental impact assessment and associated hydrodynamic studies along other areas of the Qatari coastal zone. Integr Environ Assess Manag 2018;14:240-251. © 2017 SETAC. © 2017 SETAC.

Uptake of radioactivity by marine surface sediments collected in Ghazaouet, west coast of Algeria

International Nuclear Information System (INIS)

Noureddine, A.; Baggoura, B.; Hocini, N.; Boulahdid, M.

1998-01-01

Samples of surface marine sediments of different grain sizes collected in Ghazaouet, a small bay on the western coast of Algeria, have been examined to measure concentrations of natural and artificial gamma-emitting radionuclides. The aim of this study is to determine the level of radioactivity and its repartition in the sedimentary area. The samples analyzed by direct counting gamma spectrometry, showed relatively high activities for natural radioactivity and revealed measurable quantities of 137 Cs, ranging from 0.66-8.47 Bq kg -1 dry weight. In addition, some of the samples of different nature were sieved in different grain-sizes, to study the uptake of radioactivity. It is found that the sediments of less than 100 μm grain-size have the highest level of uptake of radioactivity

Uptake of radioactivity by marine surface sediments collected in Ghazaouet, west coast of Algeria

Energy Technology Data Exchange (ETDEWEB)

Noureddine, A.; Baggoura, B. [Laboratoire d' Environnement, Centre de Radioprotection et de Surete (C.R.S.), Algiers (Algeria); Hocini, N. [Laboratoire de Sedimentologie, Centre de Developpement des Techniques Nucleaires (C.D.T.N.), Algiers (Algeria); Boulahdid, M. [Departement de la Pollution Chimique, Institut des Sciences de la Mer et de l' Amenagement du Littoral, Tipaza (Algeria)

1998-12-01

Samples of surface marine sediments of different grain sizes collected in Ghazaouet, a small bay on the western coast of Algeria, have been examined to measure concentrations of natural and artificial gamma-emitting radionuclides. The aim of this study is to determine the level of radioactivity and its repartition in the sedimentary area. The samples analyzed by direct counting gamma spectrometry, showed relatively high activities for natural radioactivity and revealed measurable quantities of {sup 137}Cs, ranging from 0.66-8.47 Bq kg{sup -1} dry weight. In addition, some of the samples of different nature were sieved in different grain-sizes, to study the uptake of radioactivity. It is found that the sediments of less than 100 {mu}m grain-size have the highest level of uptake of radioactivity.

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.

Marine gamma spectrometric survey

International Nuclear Information System (INIS)

Kostoglodov, V.V.

1979-01-01

Presented are theoretical problems physical and geochemical prerequisites and possibilities of practical application of the method of continuous submarine gamma-spectrometric survey and radiometric survey destined for rapid study of the surface layer of marine sediments. Shown is high efficiency and advantages of this method in comparison with traditional and widely spread in marine geology methods of bottom sediments investigation

Distribution of naturally occurring radioactivity and 137Cs in the marine sediment of Farasan island, southern red sea, Saudi Arabia

International Nuclear Information System (INIS)

Al-zahrany, A. A.; Farouk, M. A.; Al-yousef, A. A.

2012-01-01

The present work is a part of a project dedicated to measure the marine radioactivity near the Saudi Arabian coast of the Red Sea and Arabian Gulf for establishing a marine radioactivity database, which includes necessary information on the background levels of both naturally occurring and man-made radionuclides in the marine environment. Farasan Islands is a group of 84 islands (archipelago), under the administration of the Kingdom of Saudi Arabia, in the Red Sea with its main island of Farasan, which is 50 km off the coast of Jazan City. The levels of natural radioactivity of 238 U, 235 U, 226 Ra, 232 Thand 40 K and man-made radionuclides such as 137 Cs in the grab sediment and water samples around Farasan Island have been measured using gamma-ray spectroscopy. The average activity concentrations of 238 U, 235 U, 226 Ra, 232 Th, 40 K and 137C s in the sediment samples were found to be 35.46, 1.75, 3.31, 0.92, 34.34 and 0.14 Bq kg -1 , respectively. (authors)

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.

HEAVY METAL AND ANTIBIOTIC RESISTANCE BACTERIA IN MARINE SEDIMENT OF PAHANG COASTAL WATER

Directory of Open Access Journals (Sweden)

Zaima Azira

2018-01-01

Full Text Available The presence of heavy metal and antibiotic resistance bacteria in the marine sediment may indicate heavy metal pollution and antibiotic abuse present in the environment. In this study, a total of 89 bacteria isolated from sediment collected in Teluk Chempedak and Pantai Batu Hitam of Pahang coastal water underwent heavy metal resistance test against Chromium, Cadmium, Nickel, Copper and Cobalt. Previously, these isolates were found to exhibit antibiotic resistance capabilities to at least 5 antibiotics tested. Heavy metal resistance pattern for isolates from Teluk Chempedak was in the form of Cr > Ni >Co >Cd = Cu while for isolates from Pantai Batu Hitam showed a pattern of Cr = Ni >Co >Cu >Cd. Further investigation on the identity of selected isolates that exhibited both antibiotic and heavy metals resistance capabilities using 16S rRNA gene sequences revealed isolates with closest similarities to Staphylococcus saprophyticus and Brevundimonas vesicularis..

New aspects on the transuranics transfer in the Palomares marine environment

International Nuclear Information System (INIS)

Romero, L.; Lobo, A.M.; Holm, E.

1992-01-01

The environmental contamination of transuranics following the Palomares accident in 1966 (Southern Spain) has been continuous monitored on land and scientific programs are still running. The study of the land to sea transfer of the contamination started in 1986, focussed on the depositional history recorded in marine sediments. At the continental shelf, south of the mouth of the Almanzora river, enhanced levels of plutonium and americium were found which could be related to the accident. Additional analysis of marine sediments, collected far from the impact point, showed the presence of a hot particle. The study of the chronology of this sediment core and the isotopic ratios are given in this paper to assess the origin and pathway of the particle. The route of this particle was found to be the aerial transfer at the time of the accident. (author) 8 refs.; 3 figs

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.

Effects of specific inhibitors on anammox and denitrification in marine sediments.

Science.gov (United States)

Jensen, Marlene Mark; Thamdrup, Bo; Dalsgaard, Tage

2007-05-01

The effects of three metabolic inhibitors (acetylene, methanol, and allylthiourea [ATU]) on the pathways of N2 production were investigated by using short anoxic incubations of marine sediment with a 15N isotope technique. Acetylene inhibited ammonium oxidation through the anammox pathway as the oxidation rate decreased exponentially with increasing acetylene concentration; the rate decay constant was 0.10+/-0.02 microM-1, and there was 95% inhibition at approximately 30 microM. Nitrous oxide reduction, the final step of denitrification, was not sensitive to acetylene concentrations below 10 microM. However, nitrous oxide reduction was inhibited by higher concentrations, and the sensitivity was approximately one-half the sensitivity of anammox (decay constant, 0.049+/-0.004 microM-1; 95% inhibition at approximately 70 microM). Methanol specifically inhibited anammox with a decay constant of 0.79+/-0.12 mM-1, and thus 3 to 4 mM methanol was required for nearly complete inhibition. This level of methanol stimulated denitrification by approximately 50%. ATU did not have marked effects on the rates of anammox and denitrification. The profile of inhibitor effects on anammox agreed with the results of studies of the process in wastewater bioreactors, which confirmed the similarity between the anammox bacteria in bioreactors and natural environments. Acetylene and methanol can be used to separate anammox and denitrification, but the effects of these compounds on nitrification limits their use in studies of these processes in systems where nitrification is an important source of nitrate. The observed differential effects of acetylene and methanol on anammox and denitrification support our current understanding of the two main pathways of N2 production in marine sediments and the use of 15N isotope methods for their quantification.

Geochemistry of sediments

Digital Repository Service at National Institute of Oceanography (India)

Nath, B.N.

Considering the potential of elemental data in marine sediments as diagnostic tools of various geological and oceanographic processes, sediment geochemical data from the Indian Ocean region has been reviewed in this article. Emphasis is laid...

Distinct bacterial communities in surficial seafloor sediments following the 2010 Deepwater Horizon blowout

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Tingting Yang

2016-09-01

Full Text Available A major fraction of the petroleum hydrocarbons discharged during the 2010 Macondo oil spill became associated with and sank to the seafloor as marine snow flocs. This sedimentation pulse induced the development of distinct bacterial communities. Between May 2010 and July 2011, full-length 16S rRNA gene clone libraries demonstrated bacterial community succession in oil-polluted sediment samples near the wellhead area. Libraries from early May 2010, before the sedimentation event, served as the baseline control. Freshly deposited oil-derived marine snow was collected on the surface of sediment cores in September 2010, and was characterized by abundantly detected members of the marine Roseobacter cluster within the Alphaproteobacteria. Samples collected in mid-October 2010 closest to the wellhead contained members of the sulfate-reducing, anaerobic bacterial families Desulfobacteraceae and Desulfobulbaceae within the Deltaproteobacteria, suggesting that the oil-derived sedimentation pulse triggered bacterial oxygen consumption and created patchy anaerobic microniches that favored sulfate-reducing bacteria. Phylotypes of the polycyclic aromatic hydrocarbon-degrading genus Cycloclasticus, previously found both in surface oil slicks and the deep hydrocarbon plume, were also found in oil-derived marine snow flocs sedimenting on the seafloor in September 2010, and in surficial sediments collected in October and November 2010, but not in any of the control samples. Due to the relative recalcitrance and stability of polycyclic aromatic compounds, Cycloclasticus represents the most persistent microbial marker of seafloor hydrocarbon deposition that we could identify in this dataset. The bacterial imprint of the DWH oil spill had diminished in late November 2010, when the bacterial communities in oil-impacted sediment samples collected near the Macondo wellhead began to resemble their pre-spill counterparts and spatial controls. Samples collected in summer

Depth-related influences on biodegradation rates of phenanthrene in polluted marine sediments of Puget Sound, WA

International Nuclear Information System (INIS)

Tang, Yinjie J. . E-mail yjtang@lbl.gov; Carpenter, Shelly D.; Deming, Jody W.; Krieger-Brockett, Barbara

2006-01-01

A whole-core injection method was used to determine depth-related rates of microbial mineralization of 14 C-phenanthrene added to both contaminated and clean marine sediments of Puget Sound, WA. For 26-day incubations under micro-aerobic conditions, conversions of 14 C-phenanthrene to 14 CO 2 in heavily PAH-contaminated sediments from two sites in Eagle Harbor were much higher (up to 30%) than those in clean sediments from nearby Blakely Harbor ( 14 C-phenanthrene degradation rates in the surface sediment horizons (0-3 cm) were more rapid (2-3 times) than in the deeper sediment horizons examined (>6 cm), especially in the most PAH polluted EH9 site. Differences in mineralization were associated with properties of the sediments as a function of sediment depth, including grain-size distribution, PAH concentration, total organic matter and total bacterial abundance. When strictly anaerobic incubations (in N 2 /H 2 /CO 2 atmosphere) were used, the phenanthrene biodegradation rates at all sediment depths were two times slower than under micro-aerobic conditions, with methanogenesis observed after 24 days. The main rate-limiting factor for phenanthrene degradation under anaerobic conditions appeared to be the availability of suitable electron acceptors. Addition of calcium sulfate enhanced the first order rate coefficient (k 1 increased from 0.003 to 0.006 day -1 ), whereas addition of soluble nitrate, even at very low concentration ( 1 up to 0.11 day -1 )

Determination and environmental estimation of NORMs in marine sediment environment of offshore platforms

International Nuclear Information System (INIS)

Vegueria, Sergio F. Jerez

2013-01-01

The natural radioactive materials (NORM known as) are found in the earth's crust, and during the process of production of oil and gas are concentrated in the produced water and the fouling (scale) pipes used for extraction. The production of oil and gas from produced water comes, comprising: forming water (water naturally present in the well ); injection water , usually sea water previously injected into the well to maintaining the pressure while the oil is removed; and water condensed in some cases of gas production. A high radioactivity of 226 Ra (natural grade of 238 U) and 228 Ra (from the natural series of 232 Th) is detected in produced water due to the high solubility of radio in formation water as uranium and thorium, which are insoluble in this medium, remain the rock matrix. The study was conducted in the area of offshore oil production in the state of Rio de January and included the determination of uranium, 226 Ra, 210 Pb and 228 Ra in marine sediment near the points of discharge of produced water from oil platforms. After the pre-treatment and digestion of samples, the determination of the natural uranium was performed on a mass spectrometer with inductively coupled plasma (ICP -MS). The activities of 226 Ra and 228 Ra were determined by high resolution gamma spectrometry through 214 Bi and 228 Ac , respectively. And in the case of 210 Pb, a correction was made for self-absorption employing an external source of this radionuclide. The results showed that there is no impact in sediments in the vicinity of the studied platforms

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Diversity of Microbial Communities and Quantitative Chemodiversity in Layers of Marine Sediment Cores from a Causeway (Kaichu-Doro in Okinawa Island, Japan

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Taha Soliman

2017-12-01

Full Text Available Microbial community diversity and chemodiversity were investigated in marine sediments adjacent to the Okinawan “Kaichu-Doro” Causeway, which was constructed 46 years ago to connect a group of four islands (Henza-jima, Miyagi-jima, Ikei-jima, Hamahiga-jima to the Okinawan main island. This causeway was not built on pilings, but by land reclamation; hence, it now acts as a long, thin peninsula. The construction of this causeway was previously shown to have influenced the surrounding marine ecosystem, causing ecosystem fragmentation and loss of water circulation. In this study, we collected sediment cores (n = 10 from five paired sites in 1 m water depths. Each pair of sites consisted of one site each on the immediate north and south sides of the causeway. Originally the members of each pair were much closer to each other (<150 m than to other pairs, but now the members of each pair are isolated by the causeway. Each core was 60–80 cm long and was divided into 15-cm layers. We examined the vertical diversity of microbial communities and chemical compounds to determine the correlation between chemodiversity and microbial communities among marine sediment cores and layers. Principal coordinate analyses (PCoA of detected compounds and of bacterial and archaeal operational taxonomic units (OTUs revealed that the north and south sides of the causeway are relatively isolated, with each side having unique microbial OTUs. Additionally, some bacterial families (e.g., Acidaminobacteraceae, Rhizobiaceae, and Xanthomonadaceae were found only on the south side of Kaichu-Doro. Interestingly, we found that the relative abundance of OTUs for some microbial families increased from top to bottom, but this was reversed in some other families. We conclude that the causeway has altered microbial community composition and metabolite profiles in marine sediments.

Marine sediments as a radioactive pollution repository in the world

International Nuclear Information System (INIS)

Navarrete, J.M.; Mueller, G.; Zuniga, M.A.; Camacho, M.; Espinosa, G.; Golzarri, J.I.

2014-01-01

During a time period little longer than 60 years, it has been created a radioactive pollution background over the natural one, which started in 1945 and it has been growing up since then, due to several nuclear tests, minor nuclear reactors failure and four major accidents: Wind Scale, Three Mile Island, Chernobyl and Fukushima. This radioactive polluting background can be easily detected through 137 Cs fission product, which by the effect of wind, river currents and rain has been accumulated in marine sediments, mainly because sea represents about 80 % of earth's surface. Since energy demand has been growing up with no interruption during last two centuries, and nuclear energy seems to be the largest available source, it is very likely a great expansion of nuclear energy during twenty-first century. So, this paper presents results obtained in strategic points of the two large littorals in Mexico: Gulf and Pacific Ocean, as an attempt to establish there some figure to evaluate the present radioactive pollution. An adequate figure to do it, seems to be the quotient of activity per gram of 137 Cs in marine sediments (Bq 137 Cs/g), divided by activity per gram of 40 K natural radioactivity (Bq 40 K/g). When this result is multiplied by 100 the percentage of polluting radioactivity ( 137 Cs) related to natural radioactivity ( 40 K) is obtained. This percentage seems to be useful to evaluate the importance of radioactive pollution from 4 points of view: a) calculate the extent of already radioactive pollution present in the seas of world; b) avoid the panic in case of nuclear accidents, c) what will be the growing up rate in the future; d) if it is possible to keep one decreasing rate at same decaying rate of 137 Cs (t 1/2 = 30.07 years), since from 1945, starting time of radioactive pollution, it has decayed only about 2.2 half lives. (author)

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

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

OpenAIRE

S. G. Wakeham; A. P. McNichol

2014-01-01

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

Acute and chronic toxicity of sediment samples from Guanabara Bay (RJ) during the rainy period

OpenAIRE

Maranho,Luciane Alves; Abreu,Ilene Matanó; Santelli,Ricardo Erthal; Cordeiro,Renato Campelo; Soares-Gomes,Abílio; Moreira,Lucas Buruaem; Morais,Rodofley Davino; Abessa,Denis Moledo de Sousa

2010-01-01

Guanabara Bay is a marine-estuarine environment of high ecological and socio-economic importance, subject to a variety of environmental impacts. Sediment is the eventual repository for most substances introduced into water bodies and may, therefore, provide an integrated measure of the environmental quality, which can be assessed by many different approaches. In this project, the quality of sediments from Guanabara Bay was evaluated by the ecotoxicological approach: whole-sediment toxicity te...

La Sedimentation Argileuse dans le Bassin Côtier du Togo, Reflet ...

African Journals Online (AJOL)

During the marine sedimentation within the Togo coastal basin, the impact of input continental origin was very important despite their various nature and the sedimentary or diagenetic modifications demanded by active or passive receptive depositional environment. Sedimentary clays in the basin reflect climatic, tectonic ...

Isolating the impact of sediment toxicity in urban streams

International Nuclear Information System (INIS)

Marshall, Stephen; Pettigrove, Vincent; Carew, Melissa; Hoffmann, Ary

2010-01-01

Several factors can contribute to the ecological degradation of stream catchments following urbanization, but it is often difficult to separate their relative importance. We isolated the impact of polluted sediment on the condition of an urban stream in Melbourne, Australia, using two complementary approaches. Using a rapid bioassessment approach, indices of stream condition were calculated based on macroinvertebrate field surveys. Urban stream reaches supported impoverished macroinvertebrate communities, and contained potentially toxic concentrations of heavy metals and hydrocarbons. Using a field microcosm approach, a bioassay was carried out to assess sediment pollution effects on native macroinvertebrates. Sediment from urban sites substantially altered the microcosm macroinvertebrate community, most likely due to elevated heavy metal and hydrocarbon concentrations. Macroinvertebrate surveys combined with a bioassay approach based on field microcosms can help isolate the effect of stream pollutants in degraded ecosystems. - Field microcosms isolate the ecological impact of polluted sediment in an urban stream.

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

DEFF Research Database (Denmark)

Arnosti, C.; Jørgensen, BB

2006-01-01

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

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

Microplastics Monitoring in Marine Environment

Directory of Open Access Journals (Sweden)

Agung Dhamar Syakti

2017-11-01

Full Text Available This review summarizes the need for future spatiotemporal comparisons of microplastic abundance across marine environment, through standardized methods for microplastic sampling and analysis in sea water, beach and seabed sediment and marine organism. Pretreatment of the sample prior to the elimination of organic matter should be done using appropriate reagents was also described. Extraction of microplastics from environmental matrices is based on the different density of targeted microplastics with saturated salt solutions (NaCl, NaI, CaCl2, ZnCl2 and lithium metatungstate. Quantification can be achieved by microscopic techniques (binocular, stereomicroscope, fluorescence microscope and scanning electron microscope and discussion on identification methods including FTIR, Pyr-GC/MS and Raman spectroscopy will be provided. This review also endorses the importance of further study regarding the fate and impact of microplastics on marine biota and human health, especially when we acknowledge that co-pollution may occur during the transport on microplastic in marine environment.

Mapping Cumulative Impacts of Human Activities on Marine Ecosystems

OpenAIRE

, Seaplan

2018-01-01

Given the diversity of human uses and natural resources that converge in coastal waters, the potential independent and cumulative impacts of those uses on marine ecosystems are important to consider during ocean planning. This study was designed to support the development and implementation of the 2009 Massachusetts Ocean Management Plan. Its goal was to estimate and visualize the cumulative impacts of human activities on coastal and marine ecosystems in the state and federal waters off of Ma...

Possible impacts of CO2 storage on the marine environment

International Nuclear Information System (INIS)

Poremski, H.J.

2005-01-01

This study examined the potential impacts of deep-sea carbon dioxide (CO 2 ) sequestration on the marine environment. The upper layers of oceans are currently saturated with CO 2 , while deeper ocean waters remain undersaturated. Arctic and Antarctic waters have higher uptake rates of CO 2 due to their lower temperatures. CO 2 deposited in Arctic and Antarctic waters sinks to the bottom of the ocean, and is then transported to equatorial latitudes, where stored amounts of CO 2 that are not fixed by biochemical processes will be released and enter the atmosphere again after a period of approximately 1000 years. Nearly 50 per cent of CO 2 fixation occurs as a result of phytoplankton growth, which is dependent on the availability of a range of nutrients, essential trace metals, and optimal physical conditions. Fertilization-induced CO 2 fixation in the sediments of southern oceans will result in nutrient depletion of bottom layers, which will in turn result in lower primary production levels at equatorial latitudes. Current modelling approaches to CO 2 injection assume that the injected CO 2 will dissolve in a plume extending 100 m around a riser. Retention times of several hundred years are anticipated. However, further research is needed to investigate the efficacy of CO 2 deep ocean storage technologies. Increased CO 2 uptake can also increase the formation of bicarbonate (HCO 3 ) acidification, decrease pH values, and inhibit the formation of biomass in addition to impacting on the calcification of many organisms. It was concluded that ocean storage by injection or deep storage is an untenable option at present due to the fact that the effects of excessive CO 2 in marine environments are not fully understood. 22 refs., 2 tabs

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

DEFF Research Database (Denmark)

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

2000-01-01

The community structure of sulfate-reducing bacteria (SRB) of a marine Arctic sediment (Smeerenburg-fjorden, Svalbard) a-as characterized by both fluorescence in situ hybridization (FISH) and rRNA slot blot hybridization by using group- and genus-specific 16S rRNA-targeted oligonucleotide probes...... that FISH and rRNA slot blot hybridization gave comparable results. Furthermore, a combination of the two methods allowed us to calculate specific cellular rRNA contents with respect to localization in the sediment profile. The rRNA contents of Desulfosarcina-Desulfococcus cells were highest in the first 5...... mm of the sediment (0.9 and 1.4 fg, respectively) and decreased steeply with depth, indicating that maximal metabolic activity occurred close to the surface, Based on SRB cell numbers, cellular sulfate reduction rates were calculated. The rates were highest in the surface layer (0.14 fmol cell(-1...

Effects of offshore wind farms on marine wildlife—a generalized impact assessment

Science.gov (United States)

Bergström, Lena; Kautsky, Lena; Malm, Torleif; Rosenberg, Rutger; Wahlberg, Magnus; Åstrand Capetillo, Nastassja; Wilhelmsson, Dan

2014-03-01

Marine management plans over the world express high expectations to the development of offshore wind energy. This would obviously contribute to renewable energy production, but potential conflicts with other usages of the marine landscape, as well as conservation interests, are evident. The present study synthesizes the current state of understanding on the effects of offshore wind farms on marine wildlife, in order to identify general versus local conclusions in published studies. The results were translated into a generalized impact assessment for coastal waters in Sweden, which covers a range of salinity conditions from marine to nearly fresh waters. Hence, the conclusions are potentially applicable to marine planning situations in various aquatic ecosystems. The assessment considered impact with respect to temporal and spatial extent of the pressure, effect within each ecosystem component, and level of certainty. Research on the environmental effects of offshore wind farms has gone through a rapid maturation and learning process, with the bulk of knowledge being developed within the past ten years. The studies showed a high level of consensus with respect to the construction phase, indicating that potential impacts on marine life should be carefully considered in marine spatial planning. Potential impacts during the operational phase were more locally variable, and could be either negative or positive depending on biological conditions as well as prevailing management goals. There was paucity in studies on cumulative impacts and long-term effects on the food web, as well as on combined effects with other human activities, such as the fisheries. These aspects remain key open issues for a sustainable marine spatial planning.

Reciprocal sedimentation and noncorrelative hiatuses in marine-paralic siliciclastics: Miocene outcrop evidence

Energy Technology Data Exchange (ETDEWEB)

Kidwell, S.M.

1988-07-01

Deepening-upward paralic sequences present within a thicker record of shallowing-upward shelf and nonmarine sequences in Miocene siliciclastics of Maryland provide rare stratigraphic evidence for (1) coastal trapping of sediment during marine transgression, with simultaneous starvation on the open shelf (recorded by condensed skeletal lags), and (2) reciprocal switching of depositional and nondepositional conditions during regression. It follows that the regressive disconformities that define hemicyclic coastal sequences are not laterally continuous with the transgressive disconformities and condensed lags that define open-shelf hemicyclic sequences, although they are commonly depicted or assumed as such. Nor are these disconformities age correlative: marine-to-nonmarine correlations that assume lateral continuity of small-scale sequences (1 to 10 m thick; seismic parasequences) will err by as much as one-half cycle, restricting the applicability of models of punctuated aggradational cycles. The stratigraphic anatomy of parasequences is most comparable to reciprocal patterns inherent in hierarchically larger scale sequences in passive margins, where subaerial unconformities and submarine condensed intervals have recently been biostratigraphically verified as offset in age.

Ca Isotope Geochemistry in Marine Deep Sea Sediments of the Eastern Pacific

Science.gov (United States)

Wittke, A.; Gussone, N. C.; Derigs, D.; Schälling, M.; Teichert, B. M.

2017-12-01

Ca isotope ratio analysis (δ44/40Ca) is a powerful tool to investigate diagenetic reactions in marine sedimentary porewater systems, as it is sensitive to processes such as carbonate dissolution, precipitation, recrystallization, ion exchange and deep fluid sources, due to the isotopic difference between dissolved Ca and solid carbonate minerals (e.g. [1];[2]). We analyzed eight sediment cores of the (paleo-) Pacific equatorial age transect. Two sediment cores show decreasing Ca isotope profiles starting at the sediment/water interface with seawater-like values down to sediment-like values due to recrystallization and an increasing in the bottom part again to seawater-like values. The other studied cores show different degrees of flattening of this middle bulge. We interpret this pattern either as an effect of sediment composition and thickness, decreasing recrystallization rates and/or fluid flux or a combination of all of these factors at the respective sampling sites. Element concentration profiles and Sr-isotope variations on some of these sediment cores show a similar behavior, supporting our findings ([3]; [4]). Seawater influx at (inactive) seamounts is supposed to cause seawater-like values at the bottom of the sediment cores by fluids migrating through the oceanic basement (e.g. [5]). While [6] hypothesizes that two seamounts or bathymetric pits are connected, with a recharge and a discharge site [7] say that uptaken fluids could be released through the surrounding seafloor as well due to diffusive exchange with the underlying oceanic crust. Our Ca isotope results combined with a transport reaction model approach support the latter hypothesis. References: [1] Teichert B. M., Gussone N. and Torres M. E. (2009) [2] Ockert C., Gussone N., Kaufhold S. and Teichert B. (2013) [3] Pälike H., Lyle M., Nishi H., Raffi I., Gamage K. and Klaus A. (eds.) (2010) [4] Voigt J., Hathorne E. C., Frank M., Vollstaedt H. and Eisenhauer A. (2015) [5] Villinger H. W

Multi-isotopic determination of plutonium (239Pu, 240Pu, 241Pu and 242Pu) in marine sediments using sector-field inductively coupled plasma mass spectrometry.

Science.gov (United States)

Donard, O F X; Bruneau, F; Moldovan, M; Garraud, H; Epov, V N; Boust, D

2007-03-28

Among the transuranic elements present in the environment, plutonium isotopes are mainly attached to particles, and therefore they present a great interest for the study and modelling of particle transport in the marine environment. Except in the close vicinity of industrial sources, plutonium concentration in marine sediments is very low (from 10(-4) ng kg(-1) for (241)Pu to 10 ng kg(-1) for (239)Pu), and therefore the measurement of (238)Pu, (239)Pu, (240)Pu, (241)Pu and (242)Pu in sediments at such concentration level requires the use of very sensitive techniques. Moreover, sediment matrix contains huge amounts of mineral species, uranium and organic substances that must be removed before the determination of plutonium isotopes. Hence, an efficient sample preparation step is necessary prior to analysis. Within this work, a chemical procedure for the extraction, purification and pre-concentration of plutonium from marine sediments prior to sector-field inductively coupled plasma mass spectrometry (SF-ICP-MS) analysis has been optimized. The analytical method developed yields a pre-concentrated solution of plutonium from which (238)U and (241)Am have been removed, and which is suitable for the direct and simultaneous measurement of (239)Pu, (240)Pu, (241)Pu and (242)Pu by SF-ICP-MS.

Evidence That Marine Reserves Enhance Resilience to Climatic Impacts

Science.gov (United States)

Micheli, Fiorenza; Saenz-Arroyo, Andrea; Greenley, Ashley; Vazquez, Leonardo; Espinoza Montes, Jose Antonio; Rossetto, Marisa; De Leo, Giulio A.

2012-01-01

Establishment of marine protected areas, including fully protected marine reserves, is one of the few management tools available for local communities to combat the deleterious effect of large scale environmental impacts, including global climate change, on ocean ecosystems. Despite the common hope that reserves play this role, empirical evidence of the effectiveness of local protection against global problems is lacking. Here we show that marine reserves increase the resilience of marine populations to a mass mortality event possibly caused by climate-driven hypoxia. Despite high and widespread adult mortality of benthic invertebrates in Baja California, Mexico, that affected populations both within and outside marine reserves, juvenile replenishment of the species that supports local economies, the pink abalone Haliotis corrugata, remained stable within reserves because of large body size and high egg production of the protected adults. Thus, local protection provided resilience through greater resistance and faster recovery of protected populations. Moreover, this benefit extended to adjacent unprotected areas through larval spillover across the edges of the reserves. While climate change mitigation is being debated, coastal communities have few tools to slow down negative impacts of global environmental shifts. These results show that marine protected areas can provide such protection. PMID:22855690

Evidence that marine reserves enhance resilience to climatic impacts.

Directory of Open Access Journals (Sweden)

Fiorenza Micheli

Full Text Available Establishment of marine protected areas, including fully protected marine reserves, is one of the few management tools available for local communities to combat the deleterious effect of large scale environmental impacts, including global climate change, on ocean ecosystems. Despite the common hope that reserves play this role, empirical evidence of the effectiveness of local protection against global problems is lacking. Here we show that marine reserves increase the resilience of marine populations to a mass mortality event possibly caused by climate-driven hypoxia. Despite high and widespread adult mortality of benthic invertebrates in Baja California, Mexico, that affected populations both within and outside marine reserves, juvenile replenishment of the species that supports local economies, the pink abalone Haliotis corrugata, remained stable within reserves because of large body size and high egg production of the protected adults. Thus, local protection provided resilience through greater resistance and faster recovery of protected populations. Moreover, this benefit extended to adjacent unprotected areas through larval spillover across the edges of the reserves. While climate change mitigation is being debated, coastal communities have few tools to slow down negative impacts of global environmental shifts. These results show that marine protected areas can provide such protection.

Assessing Sub-Lethal Impacts of Petroleum Compounds on Marine Benthic Systems

Energy Technology Data Exchange (ETDEWEB)

Lindgren, J. Fredrik

2012-07-01

Petroleum and its different distillates commonly end up in the marine environment. One source of these additions is discharges originating from shipping activities; accidents, ship wrecks, operational spills etc. Depending on several different factors that govern the fate of petroleum released into the marine environment the effects of the discharge will differ, from acute toxic to long term sub-lethal effects. While effects on biota from large spills have thoroughly been investigated in the past long term sub-lethal effects are somewhat less examined. Therefore the objective of this thesis has been to develop and apply a method to analyze what effects low concentrations of petroleum, which often ends up in marine sediments, have on benthic sediment biota. Ecotoxicological endpoints that were evaluated were density changes of meiofauna and variations in the microbial community function, measured as inorganic nutrient fluxes over the sediment-water interface the potential to perform a metabolic process. These types of organisms are two important key players in marine benthic sedimentary habitats, performing ecosystem services such as degradation of organic matter, recycling of nutrients and various pollutants and they constitute a carbon link to higher trophic levels. As manual classification of meiofauna is very time-consuming process including an extended learning process for the taxonomist, this thesis is in its first part focused at the field of automatic classification. To classify meiofaunal communities a novel technique was developed where the image analysis software ZooImage was adapted to automatically classify higher taxonomic taxa of meiofauna, with successful results. The technique was evaluated by classifying meiofaunal communities from five different depths in the Gullmar Fjord, Sweden. The accuracy of the analyses was tested using ZooImage's internal 10-fold cross-validation method, and by comparing digitalized samples from the different sites

Impacts of Suspended Sediment and Estuarine - Shelf Exchange Pathways on Shelf Ecosystem Dynamics in the Northern Gulf of Mexico

Science.gov (United States)

Wiggert, J. D.; Pan, C.; Dinniman, M. S.; Lau, Y.; Fitzpatrick, P. J.; O'Brien, S. J.; Bouchard, C.; Quas, L. M.; Miles, T. N.; Cambazoglu, M. K.; Dykstra, S. L.; Dzwonkowski, B.; Jacobs, G. A.; Church, I.; Hofmann, E. E.

2017-12-01

A circulation model based on the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System, with coupled biogeochemical and sediment transport modules, has been implemented for Mississippi Sound and the adjacent continental shelf region. The model has 400-m horizontal resolution, 24 vertical layers, and includes wetting/drying capability to resolve shallow inshore regions. The circulation model was spun-up using oceanographic initial and lateral boundary conditions provided by a 1-km resolution regional implementation of the Navy Coastal Ocean Model (NCOM) in the Gulf of Mexico. The biogeochemical module includes multiple size classes of phytoplankton, zooplankton and detritus, a fish larvae compartment, and explicitly tracks dissolved oxygen with benthic cycling interaction. The sediment transport model is implemented based on benthic mapping data that provides bottom sediment type distributions and spatio-temporal validation. A regionally specific atmospheric forcing product that provides improved spatial and temporal resolution, including diurnal sea breeze impacts, has been developed and applied. Model experiments focus on periods when comprehensive ship-based sampling was deployed by the CONCORDE (Consortium for Coastal River-Dominated Ecosystems) research program, which was established to investigate the complex fine-scale biological, chemical and physical interactions in a marine system controlled by pulsed-river plume dynamics. Biophysical interactions and biogeochemical variability associated with estuarine - shelf exchanges between nearshore lagoonal estuarine waters and the continental shelf revealed by the model provide new insight into how seasonal variation of hydrological forcing conditions influence ecological and biogeochemical processes in the highly productive Northern Gulf region. Application of the COAWST-based model system with and without inclusion of the sediment transport module demonstrates how suspended sediment in the

The IAEA worldwide intercomparison exercises (1990-1997). Determination of trace elements in marine sediments and biological samples

International Nuclear Information System (INIS)

Coquery, M.; Carvalho, F.P.; Azemard, S.; Horvat, M.

1999-01-01

Four major worldwide intercomparison exercises for the determination of trace elements in various environmental matrices were completed by the IAEA Marine Environment Laboratory since 1990: SD-M-2/TM, deep sea marine sediment; IAEA-350, tuna fish homogenate; IAEA-356, contaminated coastal sediment and IAEA-140, sea plant (Fucus sp.). These intercomparison exercises aim at enabling individual laboratories to monitor their performance. The results of these exercises allowed us to make an overall evaluation of the quality of data provided for environmental assessment and to identify the trends of analytical performance in the determination of trace elements over the years. The number of participants in each exercise varied between 68 and 130, and permits statistical evaluation of the performance for a number of elements. For each intercomparison exercise, the performance of the participant laboratories was assessed by comparing reported results with established reference values calculating 'Z-scores'. The results show that for each sample matrix, the values reported by some laboratories were far from satisfactory in the earlier exercises, in particular for Cd, Cr and Pb. Nevertheless, over time, a general improvement of performance can clearly be seen for all elements. Moreover, there was a noticeable increase in the number of laboratories with good performance in the two most recent exercises, observed both for biological and for sediment matrices. However, the determination of trace elements such as Cd, Cr, Pb and Hg in low level environmental samples still remains a major challenge to the analysts. For this reason and in order to assess the current performance of laboratories for low environmental levels of contaminants, the future intercomparison exercises will concentrate on low level sediment and fish samples

Assessment of 238Pu and 239+240Pu, in marine sediments of the oceans Atlantic and Pacific of Guatemala

International Nuclear Information System (INIS)

Mendez Ochaita, L.

2000-01-01

In this investigation samples of marine sediments were taken from 14 places representatives of the oceans coast of Guatemala. For the assesment of 238 Pu and 239+240 Pu in sediments a radiochemical method was used to mineralize sediments and by ionic interchange it was separated from other elements, after that an electrodeposition of plutonium was made in metallic discs. The radioactivity of plutonium was measured by alpha spectrometry system and the alpha spectrums were obtained. The levels of plutonium are not higher than other countries that shown contamination. The contamination of isotope of 239+240 Pu is higher than 238 Pu and the contamination by two isotopes of plutonium is higher in the Atlantic than the Pacific ocean

Impacts of Declining Mississippi River Sediment Load on Subaqueous Delta Front Sedimentation and Geomorphology

Science.gov (United States)

Maloney, J. M.; Bentley, S. J.; Xu, K.; Georgiou, I. Y.; Miner, M. D.

2016-02-01

The Mississippi River delta system is undergoing unprecedented changes due to the effects of climate change and anthropogenic alterations to the river and its delta. Since the 1950s, the suspended sediment load of the Mississippi River has decreased by approximately 50% due to the construction of >50,000 dams in the Mississippi basin. The impact of this decreased sediment load has been observed in subaerial environments, but the impact on sedimentation and geomorphology of the subaqueous delta front has yet to be examined. To identify historic trends in sedimentation patterns, we compiled bathymetric datasets, including historical charts, industry and academic surveys, and NOAA data, collected between 1764 and 2009. Sedimentation rates are variable across the delta front, but are highest near the mouth of Southwest Pass, which carries the largest percentage of Mississippi River flow and sediment into the Gulf of Mexico. The progradation rate of Southwest Pass (measured at the 10 m depth contour) has slowed from 67 m/yr between 1764 and 1940 to 26 m/yr between 1940 and 1979, with evidence of further deceleration from 1979-2009. Decreased rates of progradation are also observed at South Pass and Pass A Loutre, with the 10 m contour retreating at rates >20 m/yr at both passes. Advancement of the delta front also decelerated in deeper water (15-90 m) offshore from Southwest Pass. In this area, from 1940-1979, depth contours advanced seaward 30 m/yr, but rates declined from 1979-2005. Furthermore, over the same area, the sediment accumulation rate decreased by 81% for the same period. The Mississippi River delta front appears to be entering a phase of decline, which will likely be accelerated by future upstream management practices. This decline has implications for offshore ecosystems, biogeochemical cycling, pollutant dispersal, mudflow hazard, and the continued use of the delta as an economic and population center.

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

Towards a meaningful assessment of marine ecological impacts in life cycle assessment (LCA).

Science.gov (United States)

Woods, John S; Veltman, Karin; Huijbregts, Mark A J; Verones, Francesca; Hertwich, Edgar G

2016-01-01

Human demands on marine resources and space are currently unprecedented and concerns are rising over observed declines in marine biodiversity. A quantitative understanding of the impact of industrial activities on the marine environment is thus essential. Life cycle assessment (LCA) is a widely applied method for quantifying the environmental impact of products and processes. LCA was originally developed to assess the impacts of land-based industries on mainly terrestrial and freshwater ecosystems. As such, impact indicators for major drivers of marine biodiversity loss are currently lacking. We review quantitative approaches for cause-effect assessment of seven major drivers of marine biodiversity loss: climate change, ocean acidification, eutrophication-induced hypoxia, seabed damage, overexploitation of biotic resources, invasive species and marine plastic debris. Our review shows that impact indicators can be developed for all identified drivers, albeit at different levels of coverage of cause-effect pathways and variable levels of uncertainty and spatial coverage. Modeling approaches to predict the spatial distribution and intensity of human-driven interventions in the marine environment are relatively well-established and can be employed to develop spatially-explicit LCA fate factors. Modeling approaches to quantify the effects of these interventions on marine biodiversity are less well-developed. We highlight specific research challenges to facilitate a coherent incorporation of marine biodiversity loss in LCA, thereby making LCA a more comprehensive and robust environmental impact assessment tool. Research challenges of particular importance include i) incorporation of the non-linear behavior of global circulation models (GCMs) within an LCA framework and ii) improving spatial differentiation, especially the representation of coastal regions in GCMs and ocean-carbon cycle models. Copyright © 2016 Elsevier Ltd. All rights reserved.

Supercritical-flow structures (backset-bedded sets and sediment waves) on high-gradient clinoform systems influenced by shallow-marine hydrodynamics

Science.gov (United States)

Massari, F.

2017-10-01

Inferred supercritical structures and bedforms, including sediment waves and backset-bedded sets, are identified as components of coarse-grained siliciclastic and bioclastic, high-gradient clinoform wedges (Plio-Pleistocene of southern Italy) and canyon head infills (Tortonian of Venetian pre-Alps), showing evidence of having been built out in a setting influenced by shallow-marine hydrodynamics. The facies identified are dominated by a range of traction carpets, formed after segregation of coarser particles in the lower part of bipartite density underflows. The generation of backset-bedded sets is thought to imply scouring due to impact of a submerged hydraulic jump on the bed, and upstream migration of the jump, concomitant with the deposition of backset beds on the stoss side of the developing bedform. Submerged hydraulic jumps apparently formed spontaneously and in any position on the foreset and toeset, without requiring any precursor bed defect. The mostly solitary, non-cyclical character of the bedforms prevents their attribution to cyclic steps. The sets of backset beds are locally underlain by chaotic infills of deep, steep-sided scours attributed to vigorous erosion at the hydraulic jump, accompanied by instantaneous loss in transport capacity which results in rapid plugging of the scour (hydraulic jump facies of Postma et al., 2014). Gravel waves have a distinct internal stratigraphy, and their length to amplitude ratios show lower mean values and higher variability when compared to sediment waves consisting of sand. The presence of supercritical bedforms on steep foreset slopes of the studied clinoform systems, even in proximity to the topset-foreset rollover, is believed to reflect high inefficiency of mud-poor and short run-out bipartite underflows episodically transporting relatively small volumes of coarse-grained sediment. This may also account for common solitary, non-cyclical bedforms. It is proposed that during intense oceanographic events, such

Metabolism of polychlorinated biphenyls by marine bacteria

International Nuclear Information System (INIS)

Carey, A.E.; Harvey, G.R.

1978-01-01

There have been no reports of laboratory studies of PCB metabolism by marine organisms. A few workers have analyzed marine animals for products of PCB metabolism. A search for hydroxylated PCBs in marine fish proved inconclusive. Phenolic metabolites of PCBs have been identified in seals and guillemot. PCBs that had been hydroxylated and excreted by marine organisms would most likely be found in the sediments, so in our laboratory we conducted a search for these compounds in marine sediments. Two kilograms of organic-rich surface sediment from Buzzards Bay, Massachusetts, were extracted. The phenolic fraction was isolated and analyzed by gas chromatography-mass spectrometry (GC-MS). Neither wide mass scans nor selected mass searches produced any evidence of hydroxylated PCB derivatives. It was felt that if any marine organisms were capable of metabolism of PCBs, some marine bacteria should have that capability. Thus a series of laboratory experiments was conducted to test this possibility. Reported here is the finding of PCB metabolism by marine bacteria in batch culture

Assessing the potential of amino acid δ13C patterns as a carbon source tracer in marine sediments: effects of algal growth conditions and sedimentary diagenesis

Science.gov (United States)

Larsen, T.; Bach, L. T.; Salvatteci, R.; Wang, Y. V.; Andersen, N.; Ventura, M.; McCarthy, M. D.

2015-01-01

Burial of organic carbon in marine sediments has a profound influence in marine biogeochemical cycles, and provides a sink for greenhouse gases such as CO2 and CH4. However, tracing organic carbon from primary production sources as well as its transformations in the sediment record remains challenging. Here we examine a novel but growing tool for tracing biosynthetic origin of amino acid carbon skeletons, based on natural occurring stable carbon isotope patterns in individual amino acids (δ13CAA). We focus on two important aspects for δ13CAA utility in sedimentary paleoarchives: first, the fidelity of source diagnostic of algal δ13CAA patterns across different oceanographic growth conditions; and second, the ability of δ13CAA patterns to record the degree of subsequent microbial amino acid synthesis after sedimentary burial. Using the marine diatom Thalassiosira weissflogii, we tested under controlled conditions how δ13CAA patterns respond to changing environmental conditions, including light, salinity, temperature, and pH. Our findings show that while differing oceanic growth conditions can change macromolecular cellular composition, δ13CAA isotopic patterns remain largely invariant. These results underscore that δ13CAA patterns should accurately record biosynthetic sources across widely disparate oceanographic conditions. We also explored how δ13CAA patterns change as a function of age, total nitrogen and organic carbon content after burial, in a marine sediment core from a coastal upwelling area off Peru. Based on the four most informative amino acids for distinguishing between diatom and bacterial sources (i.e. isoleucine, lysine, leucine and tyrosine), bacterial derived amino acids ranged from 10-15% in the sediment layers from the last 5000 years to 35% during the last glacial period. The larger bacterial fractions in older sediments indicate that bacterial activity and amino acid resynthesis progressed, approximately as a function of sediment age, to

Effects of offshore wind farms on marine wildlife—a generalized impact assessment

International Nuclear Information System (INIS)

Bergström, Lena; Kautsky, Lena; Malm, Torleif; Åstrand Capetillo, Nastassja; Rosenberg, Rutger; Wahlberg, Magnus; Wilhelmsson, Dan

2014-01-01

Marine management plans over the world express high expectations to the development of offshore wind energy. This would obviously contribute to renewable energy production, but potential conflicts with other usages of the marine landscape, as well as conservation interests, are evident. The present study synthesizes the current state of understanding on the effects of offshore wind farms on marine wildlife, in order to identify general versus local conclusions in published studies. The results were translated into a generalized impact assessment for coastal waters in Sweden, which covers a range of salinity conditions from marine to nearly fresh waters. Hence, the conclusions are potentially applicable to marine planning situations in various aquatic ecosystems. The assessment considered impact with respect to temporal and spatial extent of the pressure, effect within each ecosystem component, and level of certainty. Research on the environmental effects of offshore wind farms has gone through a rapid maturation and learning process, with the bulk of knowledge being developed within the past ten years. The studies showed a high level of consensus with respect to the construction phase, indicating that potential impacts on marine life should be carefully considered in marine spatial planning. Potential impacts during the operational phase were more locally variable, and could be either negative or positive depending on biological conditions as well as prevailing management goals. There was paucity in studies on cumulative impacts and long-term effects on the food web, as well as on combined effects with other human activities, such as the fisheries. These aspects remain key open issues for a sustainable marine spatial planning. (paper)

Field application of activated carbon amendment for in-situ stabilization of polychlorinated biphenyls in marine sediment.

Science.gov (United States)

Cho, Yeo-Myoung; Ghosh, Upal; Kennedy, Alan J; Grossman, Adam; Ray, Gary; Tomaszewski, Jeanne E; Smithenry, Dennis W; Bridges, Todd S; Luthy, Richard G

2009-05-15

We report results on the first field-scale application of activated carbon (AC) amendment to contaminated sediment for in-situ stabilization of polychlorinated biphenyls (PCBs). The test was performed on a tidal mud flat at South Basin, adjacent to the former Hunters Point Naval Shipyard, San Francisco Bay, CA. The major goals of the field study were to (1) assess scale up of the AC mixing technology using two available, large-scale devices, (2) validate the effectiveness of the AC amendment at the field scale, and (3) identify possible adverse effects of the remediation technology. Also, the test allowed comparison among monitoring tools, evaluation of longer-term effectiveness of AC amendment, and identification of field-related factors that confound the performance of in-situ biological assessments. Following background pretreatment measurements, we successfully incorporated AC into sediment to a nominal 30 cm depth during a single mixing event, as confirmed by total organic carbon and black carbon contents in the designated test plots. The measured AC dose averaged 2.0-3.2 wt% and varied depending on sampling locations and mixing equipment. AC amendment did not impact sediment resuspension or PCB release into the water column over the treatment plots, nor adversely impactthe existing macro benthic community composition, richness, or diversity. The PCB bioaccumulation in marine clams was reduced when exposed to sediment treated with 2% AC in comparison to the control plot Field-deployed semi permeable membrane devices and polyethylene devices showed about 50% reduction in PCB uptake in AC-treated sediment and similar reduction in estimated pore-water PCB concentration. This reduction was evident even after 13-month post-treatment with then 7 months of continuous exposure, indicating AC treatment efficacy was retained for an extended period. Aqueous equilibrium PCB concentrations and PCB desorption showed an AC-dose response. Field-exposed AC after 18 months

Holocene environmental changes recorded in Dicksonfjorden and Woodfjorden, Svalbard: impacts of global climate changes in a glacial-marine system

Science.gov (United States)

Joo, Y. J.; Nam, S. I.; Son, Y. J.; Forwick, M.

2017-12-01

Fjords in the Svalbard archipelago are characterized by an extreme environmental gradient between 1) the glacial system affected by tidewater glaciers and seasonal sea ice inside the fjords and 2) the warm Atlantic Water intrusion by the West Spitsbergen Current from open ocean. As sediment is largely supplied from the terrestrial source area exposed along the steep slopes of the fjords, the changes in the surface processes affected by glaciers are likely preserved in the sediments in the inner fjords. On the other hand, variations in the influence of the warm Atlantic Water in the marine realm (e.g. marine productivity) can be archived in the sediment deposited in the vicinity of the entrance to the fjords. Since the last deglaciation of the Svalbard-Barents ice sheet ( 13000 yrs BP), the Svalbard fjords have faced dramatic climate changes including the early Holocene Climate Optimum (HCO) and subsequent cooling that eventually led to the current cold and dry climate. We investigate the Holocene environmental changes in both terrestrial and marine realms based on stable isotopic and inorganic geochemical analyses of sediments deposited in Dicksonfjorden and Woodfjorden in the western and northern Spitsbergen, respectively. The two fjords are expected to provide intriguing information regarding how terrestrial and marine realms of the Arctic fjords system responded to regional and global climate changes. Being a branch of the larger Isfjorden, Dicksonfjorden penetrates deeply to the land, whereas Woodfjorden is rather directly connected to the open ocean. Accordingly, the results suggest that the Dicksonfjorden sediment records mainly terrestrial signals with marked fluctuations in sediment composition that coincide with major climate changes (e.g. HCO). On the contrary, the two Woodfjorden cores collected from different parts of the fjord exhibit contrasting results, likely illustrating differing response of terrestrial and marine realms to the climate changes in

A comparative study of the flux and fate of the Mississippi and Yangtze river sediments

Directory of Open Access Journals (Sweden)

K. Xu

2015-03-01

Full Text Available Large rivers play a key role in delivering water and sediment into the global oceans. Large-river deltas and associated coastlines are important interfaces for material fluxes that have a global impact on marine processes. In this study, we compare water and sediment discharge from Mississippi and Yangtze rivers by assessing: (1 temporal variation under varying climatic and anthropogenic impacts, (2 delta response of the declining sediment discharge, and (3 deltaic lobe switching and Holocene sediment dispersal patterns on the adjacent continental shelves. Dam constructions have decreased both rivers’ sediment discharge significantly, leading to shoreline retreat along the coast. The sediment dispersal of the river-dominated Mississippi Delta is localized but for the tide-dominated Yangtze Delta is more diffuse and influenced by longshore currents. Sediment declines and relative sea level rises have led to coastal erosion, endangering the coasts of both rivers.

Intercomparison of radionuclide measurements in marine sediment sample IAEA-135

Energy Technology Data Exchange (ETDEWEB)

Ballestra, S; Gastaud, J; Lopez, J J; Parsi, P; Vas, D

1993-08-01

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

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dynamic of sulphate-reducing microorganisms in petroleum-contaminated marine sediments inhabited by the polychaete Hediste diversicolor.

Science.gov (United States)

Stauffert, Magalie; Cravo-Laureau, Cristiana; Duran, Robert

2015-10-01

The behaviour of sulphate-reducing microbial community was investigated at the oxic-anoxic interface (0-2 cm) of marine sediments when submitted to oil and enhanced bioturbation activities by the addition of Hediste diversicolor. Although total hydrocarbon removal was not improved by the addition of H. diversicolor, terminal restriction fragment length polymorphism (T-RFLP) analyses based on dsrAB (dissimilatory sulphite reductase) genes and transcripts showed different patterns according to the presence of H. diversicolor which favoured the abundance of dsrB genes during the early stages of incubation. Complementary DNA (cDNA) dsrAB libraries revealed that in presence of H. diversicolor, most dsrAB sequences belonged to hydrocarbonoclastic Desulfobacteraceae, suggesting that sulphate-reducing microorganisms (SRMs) may play an active role in hydrocarbon biodegradation in sediments where the reworking activity is enhanced. Furthermore, the presence of dsrAB sequences related to sequences found associated to environments with high dinitrogen fixation activity suggested potential N2 fixation by SRMs in bioturbated-polluted sediments.

Noise in the Sea and Its Impacts on Marine Organisms

Science.gov (United States)

Peng, Chao; Zhao, Xinguo; Liu, Guangxu

2015-01-01

With the growing utilization and exploration of the ocean, anthropogenic noise increases significantly and gives rise to a new kind of pollution: noise pollution. In this review, the source and the characteristics of noise in the sea, the significance of sound to marine organisms, and the impacts of noise on marine organisms are summarized. In general, the studies about the impact of noise on marine organisms are mainly on adult fish and mammals, which account for more than 50% and 20% of all the cases reported. Studies showed that anthropogenic noise can cause auditory masking, leading to cochlear damage, changes in individual and social behavior, altered metabolisms, hampered population recruitment, and can subsequently affect the health and service functions of marine ecosystems. However, since different sampling methodologies and unstandarized measurements were used and the effects of noise on marine organisms are dependent on the characteristics of the species and noise investigated, it is difficult to compare the reported results. Moreover, the scarcity of studies carried out with other species and with larval or juvenile individuals severely constrains the present understanding of noise pollution. In addition, further studies are needed to reveal in detail the causes for the detected impacts. PMID:26437424

Lasting Impact of a Tsunami Event on Sediment-Organism Interactions in the Ocean

Science.gov (United States)

Seike, Koji; Sassa, Shinji; Shirai, Kotaro; Kubota, Kaoru

2018-02-01

Although tsunami sedimentation is a short-term phenomenon, it may control the long-term benthic environment by altering seafloor surface characteristics such as topography and grain-size composition. By analyzing sediment cores, we investigated the long-term effect of the 2011 tsunami generated by the Tohoku Earthquake off the Pacific coast of Japan on sediment mixing (bioturbation) by an important ecosystem engineer, the heart urchin Echinocardium cordatum. Recent tsunami deposits allow accurate estimation of the depth of current bioturbation by E. cordatum, because there are no preexisting burrows in the sediments. The in situ hardness of the substrate decreased significantly with increasing abundance of E. cordatum, suggesting that echinoid bioturbation softens the seafloor sediment. Sediment-core analysis revealed that this echinoid rarely burrows into the coarser-grained (medium-grained to coarse-grained) sandy layer deposited by the 2011 tsunami; thus, the vertical grain-size distribution resulting from tsunami sedimentation controls the depth of E. cordatum bioturbation. As sandy tsunami layers are preserved in the seafloor substrate, their restriction on bioturbation continues for an extended period. The results demonstrate that understanding the effects on seafloor processes of extreme natural events that occur on geological timescales, including tsunami events, is important in revealing continuing interactions between seafloor sediments and marine benthic invertebrates.

Dating of sediments and determination of sedimentation rate. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Illus, E [ed.

1998-08-01

The Second NKS (Nordic Nuclear Safety Research)/EKO-1 Seminar was held at the Finnish Centre for Radiation and Nuclear Safety (STUK) on April 2-3, 1997. The work of the NKS is based on 4-year programmes; the current programme having been planned for the years 1994-1997. The programme comprises 3 major fields, one of them being environmental effects (EKO). Under this umbrella there are 4 main projects. The EKO-1 project deals with marine radioecology, in particular bottom sediments and sediment processes. The programme of the second seminar consisted of 8 invited lecturers and 6 other scientific presentations. Dating of sediments and determination of sedimentation rate are important in all types of sedimentological study and model calculations of fluxes of substances in the aquatic environment. In many cases these tasks have been closely related to radioecological studies undertaken in marine and fresh water environments, because they are often based on measured depth profiles of certain natural or artificial radionuclides present in the sediments. During recent decades Pb-210 has proved to be very useful in dating of sediments, but some other radionuclides have also been successfully used, e.g. Pu-239,240, Am-241 and Cs-137. The difficulties existing and problems involved in dating of sediments, as well as solutions for resolving these problems are discussed in the presentations