TY - JOUR. T1 - Integrated ocean drilling program expedition 317 preliminary report canterbury basin sea level global and local controls on continental margin stratigraphy. AU - Fulthorpe, Craig S.. AU - Hoyanagi, Koichi. AU - Blum, Peter. AU - Guèrin, Gilles. AU - Slagle, Angela L.. AU - Blair, Stacie A.. AU - Browne, Gregory H.. AU - Carter, Robert M.. AU - Ciobanu, Maria Cristina. AU - Claypool, George E.. AU - Crundwell, Martin P.. AU - Dinarès-Turell, Jaume. AU - Ding, Xuan. AU - George, Simon C.. AU - Hepp, Daniel A.. AU - Jaeger, John. AU - Kawagata, Shungo. AU - Kemp, David B.. AU - Kim, Young Gyun. AU - Kominz, Michelle A.. AU - Lever, Helen. AU - Lipp, Julius Sebastian. AU - Marsaglia, Kathleen M.. AU - McHugh, Cecilia M.. AU - Murakoshi, Naomi. AU - Ohi, Takeshi. AU - Pea, Laura. AU - Richaud, Mathieu. AU - Suto, Itsuki. AU - Tanabe, Susumu. AU - Tinto, Kirsteen J.. AU - Uramoto, Goichiro. AU - Yoshimura, Toshihiro. PY - 2010. Y1 - 2010. N2 - Integrated Ocean Drilling Program (IODP) ...
Sediment community oxygen consumption (SCOC) is a proxy for organic matter processing and thus provides a useful proxy of benthic ecosystem function. Oxygen uptake in deep-sea sediments is mainly driven by bacteria, and the direct contribution of benthic macro- and mega-infauna respiration is thought to be relatively modest. However, the main contribution of infaunal organisms to benthic respiration, particularly large burrowing organisms, is likely to be indirect and mainly driven by processes such as feeding and bioturbation that stimulate bacterial metabolism and promote the chemical oxidation of reduced solutes. Here, we estimate the direct and indirect contributions of burrowing shrimp (Eucalastacus cf. torbeni) to sediment community oxygen consumption based on incubations of sediment cores from 490 m depth on the continental slope of New Zealand. Results indicate that the presence of one shrimp in the sediment is responsible for an oxygen uptake rate of about 40 µmol d−1, only 1% of ...
Sediments in the Trinity River were chemically, physically and biologically characterized and assessed for toxicity. Laboratory bioassays were conducted to identify sediments which induced toxic responses in test organisms and to document these responses through time. Metal and organic contaminant concentrations in bottom sediments were measured. Relationships between these concentrations and biological responses observed in laboratory bioassays were determined. Toxicity identification / reduction methods were used to characterize sediment toxicants. Sediment oxygen demand was also measured in resuspended and undisturbed bottom sediments through time. The Background Sediment Chemistry Approach and the Sediment Bioassay Approach were used to assess sediment quality. Sediment toxicity was observed in whole sediment bioassays using Chironomus tentans as the test species. A relationship between sediment contaminant concentration and toxicity was observed in approximately sixty percent of the sediments.
The effects of increasing atmospheric CO2 on ocean ecosystems are a major environmental concern, as rapid shoaling of the carbonate saturation horizon is exposing vast areas of marine sediments to corrosive waters worldwide. Natural CO2 gradients off Vulcano, Italy, have revealed profound ecosystem changes along rocky shore habitats as carbonate saturation levels decrease, but no investigations have yet been made of the sedimentary habitat. Here, we sampled the upper 2 cm of volcanic sand in three zones, ambient (median pCO(2) 419 mu atm, minimum Omega(arag) 3.77), moderately CO2-enriched (median pCO(2) 592 mu atm, minimum Omega(arag) 2.96), and highly CO2-enriched (median pCO(2) 1611 mu atm, minimum Omega(arag) 0.35). We tested the hypothesis that increasing levels of seawater pCO(2) would cause significant shifts in sediment bacterial community composition, as shown recently in epilithic biofilms at the study site. In this study, 454 pyrosequencing of the V1 to V3 region of the 16S rRNA gene ...
This map shows the stacked vertical distribution of nonlithified surficial earth materials within the Marlborough quadrangle. This series of maps shows these deposits as they are vertically arranged in units from bottom to top. Surficial materials include mineral and rock particles in glacial deposits, and mineral, rock, and organic particles in postglacial deposits. Surficial materials also are known in engineering classifications as unconsolidated soils, which include coarse grained soils, fine grained soils, or organic fine grained soils. Surficial materials underlie and are the parent materials of modem pedogenic soils which have developed in them at the land surface. Delineation of the materials is based on surficial geologic mapping (Stone, 1978, Hildreth, 2003, 2004), the identification of glacial meltwater morphosequence deposits, knowledge of the deglaciation history of New England, and examination of borehole logs and water well records. For this set of maps, glacial meltwater deposits ...
Callianassid shrimps are the dominant endofauna of reef-top sediments on John Brewer Reef, a small platform reef in the central section of Australias Great Barrier Reef Province. Sediment reworking by these shrimps was investigated using the 210 Pb radioisotope in conjunction with 14 C radiometry and textural data. 210 Pb analyses of cores from two reef-top sites revealed a classical tripartite subdivision characteristic of depositional settings in which sediment reworking dominates over sediment accumulation: (1) A vertical surface mixed layer (SML) extending to a depth of nearly equal 50 cm beneath the sediment surface and representing a zone of intensive callianassid reworking; (2) An intermediate region of radioactive attenuation in which excess 210 Pb activity decreases logarithmically to a depth of slightly more than one meter beneath the sediment surface, and interpreted as representing a region utilized less frequently by Callianassa for coarse grain storage and predator avoidance; (3) ...
The microbial communities associated with electrodes from underwater fuel cells harvesting electricity from five different aquatic sediments were investigated. Three fuel cells were constructed with marine, salt-marsh, or freshwater sediments incubated in the laboratory. Fuel cells were also deployed in the field in salt marsh sediments in New Jersey and estuarine sediments in Oregon, USA. All of the sediments produced comparable amounts of power. Analysis of 16S rRNA gene sequences after 3-7 months of incubation demonstrated that all of the energy-harvesting anodes were highly enriched in microorganisms in the delta-Proteobacteria when compared with control electrodes not connected to a cathode. Geobacteraceae accounted for the majority of delta-Proteobacterial sequences or all of the energy-harvesting anodes, except the one deployed at the Oregon estuarine site. Quantitative PCR analysis of 16S rRNA genes and culturing studies indicated that Geobacteraceae were 100-fold more abundant on the ...
TY - JOUR. T1 - The effect of particle size on sorption of estrogens, androgens and progestagens in aquatic sediment. AU - Sangster, Jodi L.. AU - Oke, Hugues. AU - Zhang, Yun. AU - Bartelt-Hunt, Shannon L. PY - 2015/12/5. Y1 - 2015/12/5. N2 - There is increasing evidence of enhanced transport and biological effects stemming from steroid hormones associated with soils or sediments; however, there are limited studies evaluating how steroid hormone distribution between various particle sizes within whole sediments affects steroid fate. In this study, sorption of 17β-estradiol, estrone, progesterone, and testosterone was evaluated to different size fractions of two natural sediments, a silty loam and a sandy sediment, to determine the steroid sorption capacity to each fraction and distribution within the whole sediment. Sorption isotherms for all steroid hormones fit linear sorption models. Sorption capacity was influenced more by organic carbon content than particle size. Interactions between ...
Sediment management includes different steps in handling (uptake/dredging, transport and disposal), characterization, and sediment quality assessment, which are necessary during construction activities and for the protection and remediation of water bodies. Often, sediment management concepts need holistic understanding of the processes, which are involved in sediment genesis and erosion under specific conditions in different river basins, to work together with the forces of nature and not against them. Sediment management also includes the understanding of sediment contamination such as source control and remediation. In order to protect water bodies, it is therefore necessary to deepen our knowledge on the interaction of water, sediments, microorganisms and rocks, the mobility and transport of pollutants, the development of new technologies for the remediation of contaminated sediments, and the hydrogeochemical modeling of the interaction of contaminants with the sediments.. The symposium will ...
The factors controlling the relative abundances of Archaea and Bacteria in marine sediments are poorly understood. We determined depth distributions of archaeal and bacterial 16S rRNA genes by quantitative PCR at eight stations in Aarhus Bay, Denmark. Bacterial outnumber archaeal genes 10-60-fold in uppermost sediments that are irrigated and mixed by macrofauna. This bioturbation is indicated by visual observations of sediment color and faunal tracks, by porewater profiles of dissolved inorganic carbon and sulfate, and by distributions of unsupported 210Pb and 137Cs. Below the depth of bioturbation, the relative abundances of archaeal genes increase, accounting for one third of 16S rRNA genes in the sulfate zone, and half of 16S rRNA genes in the sulfate-methane transition zone and methane zone. Phylogenetic analyses reveal a strong shift in bacterial and archaeal community structure from bioturbated sediments to underlying layers. Stable isotopic analyses on organic matter and porewater ...
Lanthanum-modified bentonite clay (Phoslock®) is a lake remediation tool designed to strip dissolved phosphorus (P) from the water column and increase the sediment P-sorption capacity. This study investigated short term alterations in sediment elemental composition and sediment P-fractions based on sediment cores taken 2 days before and 28 days following the application of 24 t of Phoslock® to a 9 ha, man-made reservoir. Following the application, sediment lanthanum (La) content increased significantly (p , 0.05; n = 4) in the top 8 cm of the sediment, thereby theoretically increasing sediment P-binding capacity on the whole reservoir scale by 250 kg. Mass balance calculations were used to estimate the theoretical binding of release-sensitive P (Pmobile; sum of labile P, reductant-soluble P and organic P fraction) by La across the top 4 cm and 10 cm depth of sediment. The amended mass of La in the sediment had the potential to bind 42% of Pmobile present in the top 4 cm or 17% of Pmobile ...
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 I-129 is continuously produced and released from nuclear fuel reprocessing plants, and as a biophilic element, its environmental mobility is strongly linked to organic matter.. Due to its long half-life (15.7 million years), I-129 builds up in the environment and can be traced since the beginning of the nuclear era in reservoirs such as soils and marine sediments. Nevertheless, partition of the isotope between the different types of organic matter in soil and sediment is rarely explored. Here we present a sequential extraction of I-129 and I-127 chemical forms encountered in a Danish soil, a soil reference material (IAEA-375), an anoxic marine sediment from Southern Norway and an oxic sediment from the Barents Sea. The different forms of iodine are related to water soluble, exchangeable, carbonates, oxides as well as iodine ...
Suess, Erwin, von Huene, Roland, Emeis, Kay-Christian, Bourgois, Jacques, Cruzado Castaneda, Jose del C., De Wever, Patrick, Eglinton, Geoffrey, Garrison, Robert, Greenberg, Matt, Paz, Elard Herrera, Hill, Philip R., Ibaraki, Masako, Kastner, Miriam, Kemp, Alan E.S., Kvenvolden, Keith A., Langridge, Robert, Lindsley-Griffin, Nancy, Marsters, Janice, Martini, Erlend, McCabe, Robert; Ocola, Leonidas, Resig, Johanna, Sanchez Fernandez, Agapito Wilfredo, Schrader, Hans-Joachim, Thornburg, Todd M, Wefer, Gerold, and Yamano, Makoto, 1988, Proceedings of the Ocean Drilling Program, Peru continental margin; covering Leg 112 of the cruises of the drilling vessel JOIDES Resolution, 20 October 1986-25 December 1986, in Stewart, Sondra K., ed., Proceedings of the Ocean Drilling Program, Peru continental margin; covering Leg 112 of the cruises of the drilling vessel JOIDES Resolution, 20 October 1986-25 December 1986: Proceedings of the Ocean Drilling Program, Part A: Initial Reports, v. 112, 1015 p. Suess, ...
Aggregates is the collective term for sand, gravel and crushed rock. They are used as raw materials for the construction industry as well as for beach replenishment schemes. During aggregate extraction, the unwanted part of the sediment is discarded back into the water or onto the seabed. Consequently, changes occur to the size of sediment particles, which can alter the natural seabed and the invertebrates living on or inside it (De Groot 1996). Limits for acceptable change in particle size during aggregate extraction can be set, with the aim of reducing the amount of alteration to seabed sediment properties. This may facilitate recovery following cessation of activities post-extraction (Cooper 2013). Additional evidence for intervention related to sediment discard during aggregate extraction and other activities are summarised under Threat: Energy production and mining - Limit, cease, or prohibit sediment discard during aggregate extraction, Remove discarded sediment material from the ...
Polynuclear aromatic hydrocarbons (PAHs) are a class of contaminants commonly found in bottom sediments near highly industrialized areas. Resuspension of these sediments can make these contaminants more available for dispersal into the marine environment. The process will also cause the oxidation-reduction characteristics of the sediments to change from anaerobic to aerobic. Bacteria in these sediments have been shown capable of degrading 2 and 3 ring PAHs under aerobic conditions. This research examined the relationship between resuspension and biodegradation of PAHs in laboratory scale slurry reactors. Phenanthrene was used as the model compound. Radiolabeled compound was used to monitor mineralization, and mass balances were performed to determine final partitioning of carbon from degraded phenanthrene. Sediments were kept anaerobic from collection, through the contamination process, and through the loading of test reactors. Aeration of and contaminant release in sediment/water slurries was ...
Article Towards Ecosystem Based Sediment Quality Guidelines for PCB. To investigate whether Sediment Quality Guidelines (SQG) for PCBs in Canada and British Columbia achieve their objective of protecting ecosystems, we measured and compiled concentra...
Quantifying the mass transport through marine sediments, and the geochemical response to such flow with numerical models has become a common and powerful approach for geochemical data interpretation. In this dissertation, I developed and applied transport-reaction models to unravel complex and interdependent reactions involving carbon, sulfur and silica transformations in shallow marine sediments, and the impact of physical (mass transport deposits) and depositional events (volcanic ash input) on the overall geochemical state of the system. Carbon cycling in the gas hydrate bearing sediments of the Ulleung Basin was quantified using both box and kinetic modeling approaches. The box model balances mass, flux, and carbon isotopes of carbon (Chapter 2), and led to a better understanding of how methane is cycled in the marine sediments of this area. This effort demonstrates the significance of CO₂ reduction, a previously overlooked reaction. The picture of reaction network derived from this work ...
River sediment microorganisms have the capacity to metabolize, uptake and decompose flowing water organic materials, which strongly depend on their metabolic capabilities. The changes of microbial functional diversity in river sediments were analysed at five sites along the River Llobregat (NE Spain), using the Biolog EcoPlates incubation method. In parallel, we tested the potential application of the EcoPlates with preserved frozen samples (-80 °C). Although functional diversity (Shannon index) did not show significant differences, the specific carbon substrates that were used differed between sampling sites. The microbial community from the upstream site was the most active as shown by the highest respiratory activity and abundance of living bacteria, being able to metabolize more labile substrates. Downstream sediment communities showed a decrease in bacterial viability, respiration activity and EPS content, suggesting a less structured biofilm. The functional fingerprint analyses clearly ...
A testate amoeba with organic test, isolated from sediments in the Firth of Clyde, Scotland, has been assigned to a new genus as Ovulina parva (Protista: Filosea) based on its unique light microscopic and fine structural morphology. The hyaline to amber test is ovate (similar to 15x11 mu m) with a terminal aperture that is either unadorned or with a shallow collar. Hyaline, long-tapering, pointed, sometimes branched, pseudopodia emerge directly from the aperture or from the periphery of a thin web of hyaline cytoplasm. The nucleus (similar to 5 mu m) with a central nucleolus (similar to 2 mu m) is located at the posterior of the cytoplasm. The fine structure of the test, examined by scanning and transmission electron microscopy, shows it is entirely organic with an irregular to granular surface. Scattered elongate pits (similar to 1 mu m long) without perforations are distributed irregularly on the surface. Ectoplasm is distributed within a fine fibrillar envelope lining the test. The endoplasm ...
TY - JOUR. T1 - Carbon and hydrogen isotopic compositions of sterols from riverine and marine sediments. AU - Chikaraishi, Yoshito. AU - Yamada, Yusuke. AU - Naraoka, Hiroshi. PY - 2005/1/1. Y1 - 2005/1/1. N2 - The sources (marine algae, terrestrial C3 and C4 plants) of sterols deposited to sediments along a riverine-marine transect from Ohtsuchi River in Iwate Prefecture, Japan, to the northwestern Pacific Ocean were estimated using carbon (δ13C) and hydrogen isotopic compositions (δD) in surface sediments. In marine sediments, algal sterols such as 24-methylcholesta-5,22-dien-3β-ol had δ13C values of -22.7 ± 0.4‰ and δD values of -292 ± 3‰. In contrast, sterols derived from multiple potential sources, such as 24-methylcholest-5-en-3β-ol and 24-ethylcholest-5-en-3β-ol, were gradually enriched in 13C from riverine (-30.7‰ and -30.5‰, respectively) to marine sediments (-22.3‰ and -24.4‰, respectively), but showed little variation in δD values (-262 ± 1‰). These isotopic ...
With the yearly increasing marine culture activities in floating cages in Daya Bay, China, the effects of pollution may overlap and lead to more severe water environmental problems. In order to track the impacts of the marine culture in floating cages on water environment, sediments and overlying water were sampled by cylindrical samplers at three representative aquaculture areas of Daya Bay. The water content, porosity, density of sediments as well as the vertical distributions of ammonia nitrogen and active phosphate in pore water along sediments depth were measured. The release rate and annual released quantity of the nutrients across sediment-water interface were calculated using Ficks Law. A horizontal two-dimensional mathematical model was developed to compute the spatial and temporal distributions of the nutrients in seawater after being released across the sediment-water interface. The results showed that the sediments, with a high content and a large annual released quantity of nitrogen and
The following methods of measurement of sediment parameters are discussed: (1) rate of diffusional exchange of reactants and products across the sediment-water interface; (2) the concentration profiles of these reactants and profiles in the sediment, and (3) profiles and integrated rates of reactions in the sediment. The interaction of the processes of reaction and diffusion are illustrated using a simulation model. The effect of increasing organic loading (6.2, 37.2 and 62.0 mmol C m-2 d-1), with organic matter distributed in three ways: close to the sediment surface, a linear gradient downwards or evenly mixed throughout the sediment. Predictable increases in anoxic processes occurred with increasing organic loading. There were higher diffusional losses of dissolved organic matter when organic degradation occurred close to the sediment-water interface. The model predicted that degradation of organic matter at depth could have the following effects: an increase in the depth of oxygen ...
The radiogenic isotopic composition of both detrital and Fe-Mn fractions in marine sediments can be used in paleoceanography to infer changes of bottom-water circulation. We have examined various chemical techniques for the analysis of Sr and Nd isotope ratios in these fractions and present a robust method that can be used to separate both the Fe-Mn oxides and the detrital fraction from a marine sediment sample for isotopic analysis. Our sequential leaching procedure involves the use of 10% acetic acid, followed by 1 M hydroxylamine hydrochloride in 25% acetic acid to remove the carbonate component and the Fe-Mn oxide fraction, respectively. The applicability of our chemical procedure is illustrated with examples from a marine sediment core raised from the northern Cape Basin, southeast Atlantic Ocean.. ...
A three-year study of seasonal variation in water-column and sediment nitrogen species was conducted in the transition zone of the Potomac River 35 m from the Virginia shore at a site with an average water-column depth of approximately 1 m over sandy sediment. A diffusion-controlled sampler was used to collect water samples from the water column, at the interface between the water column and sediment, and at several tens of centimeters into the sediment. Nitrate was the predominant dissolved nitrogen species in the water column. The importance of denitrification was inferred by nitrate fluxes which were directed into the sediment from the water column during approximately 75% of the sampling periods and ranged from 0??02 to 0??69 mmol m-2 day-1. Flux of nitrate from the sediment into the water column, ???0??1 mmol m-2 day-1, due possibly to nitrification in surficial sediment, occurred during one spring and two summer sampling periods....
Temperate mangrove and salt marsh sediments are a small methane and nitrous oxide source but important carbon store Journal Articles Refereed ...
Studies of phosphorus (P) dynamics in surface sediments of lakes and coastal seas typically emphasize the role of coupled iron (Fe), sulfur (S) and P cycling for sediment P burial and release. Here, we show that anaerobic oxidation of methane (AOM) also may impact sediment P cycling in such systems. Using porewater and sediment profiles for sites in an oligotrophic coastal basin (Bothnian Sea), we provide evidence for the formation of Fe-bound P (possibly vivianite; Fe-3(PO4)(2)center dot 8H(2)O) below the zone of AOM with sulfate. Here, dissolved Fe2+ released from oxides is no longer scavenged by sulfide and high concentrations of both dissolved Fe2+ (,1 mM) and PO4 in the porewater allow supersaturation with respect to vivianite to be reached. Besides formation of Fe(II)-P, preservation of Fe-oxide bound P likely also contributes to permanent burial of P in Bothnian Sea sediments. Preliminary budget calculations suggest that the burial of Fe-bound P allows these sediments to act as a major ...
Scientific ocean drilling has greatly advanced the understanding of subseafloor sedimentary life. Studies of Ocean Drilling Program (ODP) and Integrated ODP samples and data show that mean per-cell rates of catabolic activity, energy flux, and biomass turnover are orders of magnitude slower in subseafloor sediment than in the surface world. They have also shown that potentially competing metabolic pathways co-occur for hundreds of meter depth in subseafloor sediment deposited over millions of years. Our study of an example site (eastern equatorial Pacific ODP Site 1226) indicates that the energy yields of these competing reactions are pinned to a thermodynamic minimum. The simplest explanation of this long-term coexistence is thermodynamic cooperation, where microorganisms utilize different but coexisting pathways that remove each others reaction products. Our Site 1226 results indicate that the energy flux to subseafloor sedimentary microbes is extremely low. Comparison to biomass turnover ...
Grandel, Sibylle; Rickert, Dirk; Schlüter, Michael; Wallmann, Klaus (2000): Geochemistry of porewater of sediment core SO129_MC-39. PANGAEA, https://doi.org/10.1594/PANGAEA.58226, In supplement to: Grandel, S et al. (2000): Pore-water distribution and quantification of diffusive benthic fluxes of silicic acid, nitrate, and phosphate in surface sediments of the deep Arabian Sea. Deep Sea Research Part II: Topical Studies in Oceanography, 47(14), 2707-2734, https://doi.org/10.1016/S0967-0645(00)00046-1
Grandel, Sibylle; Rickert, Dirk; Schlüter, Michael; Wallmann, Klaus (2000): Geochemistry of porewater of sediment core M33/1_MC-23. PANGAEA, https://doi.org/10.1594/PANGAEA.58246, In supplement to: Grandel, S et al. (2000): Pore-water distribution and quantification of diffusive benthic fluxes of silicic acid, nitrate, and phosphate in surface sediments of the deep Arabian Sea. Deep Sea Research Part II: Topical Studies in Oceanography, 47(14), 2707-2734, https://doi.org/10.1016/S0967-0645(00)00046-1
A Gram-stain-negative, non-flagellated, non-gliding and rod-shaped bacterial strain, designated TM-6T, was isolated from a tidal flat sediment in the Korean peninsula. Strain TM-6T was found to grow optimally at pH 7.0-8.0, at 30 °C and in the presence of 2-3% (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain TM-6T joined the clade comprising recognized species of the genus Fulvivirga , with which it exhibited 94.7- 95.2 % sequence similarity. Strain TM-6T was found to contain iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0 3-OH as major fatty acids. The only isoprenoid quinone was menaquinone-7 (MK-7). The major polar lipids were identified as phosphatidylethanolamine and three unidentified lipids. The DNA G+C content of strain TM-6T was 50.9 mol%. Differential phenotypic properties, together with the phylogenetic distinctiveness, revealed that strain TM-6T is distinguishable from recognized Fulvivirgaspecies. On the basis of the data presented, strain
Most often the increase of nutrients loads to coastal waters and sediment are the main cause of eutrophication-associated hypoxia. The consequent hypoxia can demolish the benthos and converted the flow of energy in the food chain downward instead of upward, thus feeding microbes in sediment [9]. Simultaneously, the pursuant hypoxia-induced release of nutrients such as phosphorus and nitrogen from deposited organic matter can be substantial and hold down the tainted consequences of external loading [10, 11]. Thermodynamically, oxygen is the most favorable electron acceptor, but the oxygen depletion in the sediment may contribute to liberate nitrogen from sediment into the water [12]. So increased nitrogen concentration and algal blooms conduct to more intense anoxia and there is a mutual prolonged effect between these processes [13]. Hypoxia can also enhance the release of nutrients from organic compounds in the sediment as ammonium is released from organic compounds by bacterial degradation ...
Overview: A primary objective of marine science classes is to learn the location and formation of ocean sediment types. Paper text and online multimedia both fall short of the experience of handling real ocean sediment. Real samples enhance learning through sight, touch, and smell, and microscope slides (smear slides for use with a petrographic microscope) allow students to better comprehend the tiny sizes and forms of various sediment components.. Real samples provide only pinpoint examples of the ocean floor, yet they swim within a virtual ocean of geological data that is best utilized with online visualization tools like Google Earth. We have merged both the real and the virtual by creating a Google Earth based supplemental information resource for each example of ocean sediment from an IODP sediment Core Kit consisting of core catcher sections and sediment smear slides that teachers may borrow for classroom instruction. 47 years of scientific ocean drilling has produced over 50,000 short ...
A 3-D hydrodynamic model is used to investigate how different size classes of river-derived sediment are transported, exported and trapped on an idealized, river-dominated tidal flat. The model is composed of a river channel flanked by sloping tidal flats, a configuration motivated by the intertidal region of the Skagit River mouth in Washington State, United States. It is forced by mixed tides and a pulse of freshwater and sediment with various settling velocities. In this system, the river not only influences stratification but also contributes a significant cross-shore transport. As a result, the bottom stress is strongly ebb-dominated in the channel because of the seaward advance of strong river flow as the tidal flats drain during ebbs. Sediment deposition patterns and mass budgets are sensitive to settling velocity. The lateral sediment spreading scales with an advective distance (settling time multiplied by lateral flow speed), thereby confining the fast settling sediment...
The aim of present work was to assess the concentration levels as well as vertical distribution of indicator bacteria including total coliform, fecal coliform, Pseudomonas aeruginosa, and Heterotrophic Plate Count (HPC) in the marine environment (seawater and coastal sediments) and evaluate the correlation between indicator bacteria and some physicochemical parameters of surface sediments as well as seawaters. A total number of 48 seawater and sediment samples were taken from 8 stations (each site 6 times with an interval time of 2 weeks) between June and September 2014. Seawater and sediment samples were collected from 30 cm under the surface samples and different sediment depths (0, 4, 7, 10, 15, and 20 cm) respectively, along the Persian Gulf in Bushehr coastal areas. Based on the results, the average numbers of bacterial indicators including total coliform, fecal coliform, and Pseudomonas aeruginosa as well as HPC in seawater samples were 1238.13, 150.87, 8.22 MPN/100 ml and 1742.91 CFU/ml,
TY - JOUR. T1 - Temperature Driven Changes in Benthic Bacterial Diversity Influences Biogeochemical Cycling in Coastal Sediments. AU - Hicks, Natalie. AU - Liu, Xuan. AU - Gregory, Richard. AU - Kenny, John. AU - Lucaci, Anita. AU - Lenzi, Luca. AU - Paterson, David M.. AU - Duncan, Katherine R.. N1 - © 2018 Hicks, Liu, Gregory, Kenny, Lucaci, Lenzi, Paterson and Duncan. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). PY - 2018/8/22. Y1 - 2018/8/22. N2 - Marine sediments are important sites for global biogeochemical cycling, mediated by macrofauna and microalgae. However, it is the microorganisms that drive these key processes. There is strong evidence that coastal benthic habitats will be affected by changing environmental variables (rising temperature, elevated CO2), and research has generally focused on the impact on macrofaunal biodiversity and ecosystem services. Despite their importance, there is less understanding of how ...
Fluxes of TDCu and Cu ligands have been determined at two sites in the Chesapeake Bay for June and October 95, and in March 96. TDCu appears to flux out of the sediments at both sites in both spring and summer. In March 95, the TDCu flux out of site M (mid-Bay) sediments (41 + or - 10 nmol/sq m/d) exceeded that at site S (southern Bay: 7 + or - 3 nmol/sq m/d). However, in June 95, the TDCu flux out at site S (52 + or - 25 nmol/sq m/d) exceeded that at site M (13 + or - 15 nmol/sq m/d). There is a significant out-flux (200 to 800 nmol/sq m/d) of total Cu-binding ligands (TLcu) from the sediments at both sites in both spring and summer, but the TLcu flux at site M exceeded that at site S. The TLcu is 3-60x greater than the TDCu flux, and the ligands fluxing out are comparable in strength (log K=15) to that of the very strong L1 class that controls the speciation of TDCu in most marine surface waters, and previously only observed in these surface waters. Sediment fluxes of this very strong ligand in June
TY - JOUR. T1 - Urban sediment particle size and pollutants in Southern Brazil. AU - Poleto, Cristiano. AU - Bortoluzzi, Edson C.. AU - Charlesworth, Susanne M.. AU - Merten, Gustavo H.. N1 - Funding Information: Acknowledgements This study was supported by CAPES, CNPq and USGS.. PY - 2009. Y1 - 2009. N2 - Background, aim and scope Studies of particulate-associated pollutants, or PAPs, in urban areas have become necessary due to their potentially deleterious effects on the environment. However, it is not just the sediments themselves which are problematic but also their particle size composition, which has a great influence on their capacity to adsorb and transport pollutants. This paper presents the particle size distributions and concentrations of five metals (Cr, Cu, Ni, Pb and Zn) of urban sediments collected from paved streets and gully pots from 20 cities in southern Brazil. The cities have different characteristics and hence sources of PAPs associated with differing geologies, soil types ...
The coupling of subseafloor microbial life to oceanographic and atmospheric conditions is poorly understood. Contreras et al. examined diagenetic imprints and lipid biomarkers of past subseafloor microbial activity to evaluate its response to glacial-interglacial cycles in a sedimentary section drilled on the Peruvian shelf (Ocean Drilling Program Leg 201, Site 1229). Multiple and distinct layers of diagenetic barite and dolomite, i.e., minerals that typically form at the sulfate−methane transition (SMT), occur at much shallower burial depth than the present SMT around 30 meters below seafloor. These shallow layers co-occur with peaks of 13C-depleted archaeol, a molecular fossil of anaerobic methane-oxidizing Archaea. Present-day, non-steady state distributions of dissolved sulfate also suggest that the SMT is highly sensitive to variations in organic carbon flux to the surface shelf sediments that may lead to shoaling of the SMT. Reaction-transport modeling substantiates our hypothesis that ...
The EFSA Panel on Plant Protection Products and their Residues (PPR Panel) was tasked to revise the Guidance Document (GD) on Aquatic Ecotoxicology under Council Directive 91/414/EEC (SANCO/3268/2001 rev. 4 (final), 17 October 2002). This scientific opinion of the PPR Panel is the second of three requested deliverables within this mandate. The scientific background for the risk assessment on sediment organisms in edge-of-field surface waters is provided, with reference to benthic ecology and ecotoxicology, available test protocols and current knowledge on exposure and effects of sediment-bound plant protection products (PPPs). The scientific opinion provides approaches on how to derive regulatory acceptable concentrations (RACs) for sediment organisms and exposure to active substances of PPPs and transformation products of these substances, and how to link them in a tiered approach to predicted environmental concentrations (PECs) for the sediment compartment. A list of uncertainties in relation ...
We investigated the impact of temperature on the microbial turnover of organic matter (OM) in a hydrothermal vent system in Guaymas Basin, by calculating microbial bio- and necromass turnover times based on the culture-independent D:L-amino acid model. Sediments were recovered from two stations near hydrothermal mounds (|74°C) and from one cold station (|9°C). Cell abundance at the two hydrothermal stations dropped from 108 to 106 cells cm-3 within ∼5 m of sediment depth resulting in a 100-fold lower cell number at this depth than at the cold site where numbers remained constant at 108 cells cm-3 throughout the recovered sediment. There were strong indications that the drop in cell abundance was controlled by decreasing OM quality. The quality of the sedimentary OM was determined by the diagenetic indicators %TAAC (percentage of total organic carbon present as amino acid carbon), %TAAN (percentage of total nitrogen present as amino acid nitrogen), aspartic acid:β-alanine ratios, and glutamic acid
We investigated the impact of temperature on the microbial turnover of organic matter (OM) in a hydrothermal vent system in Guaymas Basin, by calculating microbial bio- and necromass turnover times based on the culture-independent D:L-amino acid model. Sediments were recovered from two stations near hydrothermal mounds (8 to 106 cells cm-3 within ∼5 m of sediment depth resulting in a 100-fold lower cell number at this depth than at the cold site where numbers remained constant at 108 cells cm-3 throughout the recovered sediment. There were strong indications that the drop in cell abundance was controlled by decreasing OM quality. The quality of the sedimentary OM was determined by the diagenetic indicators %TAAC (percentage of total organic carbon present as amino acid carbon), %TAAN (percentage of total nitrogen present as amino acid nitrogen), aspartic acid:β-alanine ratios, and glutamic acid:γ-amino butyric acid ratios. All parameters indicated that the OM became progressively degraded with
679 m3 s−1 by the 2090s, an increase of between 23% and 39% relative to the baseline period, depending on the specific climate model run.. In terms of future sediment fluxes, Fig. 6c shows that under the Q0 run sediment loads on the Ganges are projected to significantly increase relative to the 1981-2000 baseline of 521 Mt per year, to 613 Mt per year by the 2050s and then 696 Mt per year by the end of the century, the latter representing an overall increase of 175 Mt per year (34%) relative to the baseline period. Under the Q8 run a similar increase in sediment load with time is also evident, with projected values of 609 Mt per year by the 2050s (a 16% increase relative to the Q8 baseline) and 714 Mt per year by the 2090s, an end of century value which is around 191 Mt per year (37%) greater than the baseline. For the Ganges, sediment loads for the Q16 run are less than both the Q0 and Q8 runs, reflecting the lower precipitation in this catchment for the Q16 run (see Fig. 3). Thus, a mean ...
The porewater chemistry was in broad agreement with the observed petrology and, in the case of the urban site, the data provides evidence of sediment disturbance. The periodic resuspension of the sediment by boat traffic results in a significant change to the surface porewater chemistry of iron and sulphate in the urban sediment and results in changes to the stability of certain authigenic phases, most notably vivianite. In the rural sediment, although physical disturbance of the sediment was observed, there was no chemical evidence in the porewater results. However, it does perhaps subtly enhance the organic matter degradation processes that are occurring, although this could not be confirmed by the results of this investigation ...
Open full size. Gas bubble emissions from bottom sediments of Lake Baikal. Methane emissions from bottom sediments in Lake Baikal have been known for a long time. Even the first travelers, who visited the lake in the 17th century, noticed gas emissions. Later gas emissions in Baikal were explored by the East Siberian Branch of the Russian Imperial Geographical Society. A review of the available materials on gas seeps in Baikal is presented in the publication [Granin and Granina, 2002]. A new stage of research on gas seeps in Baikal started after the discovery of gas hydrates [Kuzmin et al., 1998] and mud volcanoes at the bottom of the lake [Van Rensbergen et al., 2002] at the turn of the 20th century.. Gas seeps are found in oceans, seas and freshwater bodies. To study gas seeps hydroacoustic methods are used, as they enable an extensive search due to the strong backscattering of sound from the bubbles of floating-up gas. To locate and monitor the activity of gas plumes a digital record of ...
The factor analysis, used in this work for the interpretation of maturation parameters observed in an exploration study of a group of surface sediments of diverse age originating from different localities in Serbia, resulted in two significant factors. Factor 1 involved parameters related mainly to maturation changes within the aliphatic chains of the organic matter and factor 2 involved parameters based mainly on changes in the terpane and sterane rings. A statistically significant inversely proportional linear dependence between factors 1 and 2 was observed with older, in contrast to younger sediments, suggesting that the reactions of the aliphatic chains in the older sediments did not occur simultaneously with the reactions in the rings and, also, that the older surface sediments examined in this study may be characterized by a degree of thermal maturity corresponding to changes in the biomarker sterane and terpane rings, while the younger sediments by intensive changes in the aliph...atic ...
In humid, tropical regions, where chemical weathering rates are high, the relationship between bedrock lithology, stream sediment mineralogy, and stream water chemistry is neither straightforward nor well known. For a country such as Cuba, which has been isolated from much of the worlds geologic community for decades, data are sparse; yet, such data are important for understanding landscape change over time, including deciphering trends in stream water geochemistry and rates of erosion, both natural and human-caused. Here, as part of a collaborative Cuban-American project focused on understanding mass transfer from the island to the ocean, we used quantitative X-ray diffraction to determine the bulk mineral composition of river sediment in two grain sizes. We used this data to determine the relationship between sediment mineralogy and water chemistry, weathering rates, sediment elemental composition, and mapped bedrock geology in 26 central Cuban drainage basins. Diffraction data show that quartz,
We developed a microsensor for the amperometric detection of dissolved hydrogen sulfide,H2S, in sedirnents and biofilms. The mlcrosensor exhibits a fast (tgOc 0.2 to 0.5 S) and linear response to H2S over a concentration range of 1 to ,l000 pm01 H2S-I and has a low stirring dependency of the microsensor signal (c1 to 2%). We used the new mlcrosensor to obtain the first microprofiles of H2S in an acidic lake sediment with a several cm thick flocculant surface layer. Despite the low pH of 4.6, a relative low SO,- level in the lake water, and a broad O2 respiration zone of ca 6 mm, we were able to measure H2S depth profiles in the sediment at a good resolution, that allowed for calculation of specific sulfate reduction and H2S oxidation activities. Such calculations showed highest sulfate reduction activity in the anoxic sediment down to ca 20 mm depth A comparison of calculated area1 rates of O2 consumption and sulfate reduction Indicated that sulfate reduction accounted for up to 13 % of total ...
Lower Eocene to Holocene sediments recovered from Ocean Drilling Program Sites 918 and 919 were studied to determine the grain-size distribution (sand to clay sizes) and mineralogy of the ,2 m size fraction. The minerals are believed to be of detrital origin. The clay minerals consist of chlorite, smectite, illite, kaolinite, and a mixed-layer illite/smectite. Several non-clay minerals were identified as well, including quartz, plagioclase, alkali-feldspar, amphibole, pyroxene, zeolite, and calcite.. Relative abundances of the clay minerals were semiquantified using an oriented internal standard. Smectite abundances were found to increase with depth, while illite and chlorite abundances decrease with depth.. The Eocene sediments of Site 918 are characterized by a predominance of smectite with some kaolinite and very small amounts of chlorite and illite. This mineral assemblage is indicative of warm climatic conditions at the time of deposition. Oligocene sediments show an increase in chlorite ...
Background. Methane oxidizing prokaryotes in marine sediments are believed to function as a methane filter reducing the oceanic contribution to the global methane emission. In the anoxic parts of the sediments, oxidation of methane is accomplished by anaerobic methanotrophic archaea (ANME) living in syntrophy with sulphate reducing bacteria. This anaerobic oxidation of methane is assumed to be a coupling of reversed methanogenesis and dissimilatory sulphate reduction. Where oxygen is available aerobic methanotrophs take part in methane oxidation. In this study, we used metagenomics to characterize the taxonomic and metabolic potential for methane oxidation at the Tonya seep in the Coal Oil Point area, California. Two metagenomes from different sediment depth horizons (0-4 cm and 10-15 cm below sea floor) were sequenced by 454 technology. The metagenomes were analysed to characterize the distribution of aerobic and anaerobic methanotrophic taxa at the two sediment depths. To gain insight into the ...
Two new secondary metabolites, namely, pinodiketopiperazine A (1) and 6,7-dihydroxy-3-methoxy-3-methylphthalide (2), along with alternariol 2,4-dimethyl ether (3) and l-5-oxoproline methyl ester (4), which were isolated from a natural source for the first time but have been previously synthesized, were characterized from the marine sediment-derived fungus Penicillium pinophilum SD-272. In addition, six known metabolites (5-10) were also identified. Their structures were elucidated by analysis of the NMR and mass spectroscopic data. The absolute configuration of compound 1 was determined by experimental and calculated ECD spectra. Compound 2 displayed potent brine shrimp (Artemia salina) lethality with LD50 11.2 μM.
Rhodopsins are broadly distributed. In this work, we analyzed 23 metagenomes corresponding to marine sediment samples from four regions that share cold climate conditions (Norway; Sweden; Argentina and Antarctica). In order to investigate the genes evolution of viral rhodopsins, an initial set of 6224 bacterial rhodopsin sequences according to COG5524 were retrieved from the 23 metagenomes. After selection by the presence of transmembrane domains and alignment, 123 viral (51) and non-viral (72) sequences (>50 amino acids) were finally included in further analysis. Viral rhodopsin genes were homologs of Phaeocystis globosa virus and Organic lake Phycodnavirus. Non-viral microbial rhodopsin genes were ascribed to Bacteroidetes, Planctomycetes, Firmicutes, Actinobacteria, Cyanobacteria, Proteobacteria, Deinococcus-Thermus and Cryptophyta and Fungi. A rescreening using Blastp, using as queries the viral sequences previously described, retrieved 30 sequences (>100 amino acids). Phylogeographic ...
Lake sediments constitute an important compartment in the carbon cycle of lakes, by burying carbon over geological timescales and by production and emission of greenhouse gases. The degradation of organic carbon (OC) in lake sediments is linked to both temperature and oxygen (O-2), but the interactive nature of this regulation has not been studied in lake sediments in a quantitative way. We present the first systematic investigation of the effects of temperature on the apparent respiratory quotient (RQ, i.e., the molar ratio between carbon dioxide (CO2) production and O-2 consumption) in two contrasting lake sediments. Laboratory incubations of sediment cores of a humic lake and an eutrophic lake across a 1-21 degrees C temperature gradient over 157days revealed that both CO2 production and O-2 consumption were positively, exponentially, and similarly dependent on temperature. The apparent RQ differed significantly between the lake sediments (0.630.26 and 0.990.28 in the humic and the eutrophic ...
Cold seeps in the Aleutian deep-sea trench support prolific benthic communities and generate carbonate precipitates which are dependent on carbon dioxide delivered from anaerobic methane oxidation. This process is active in the anaerobic sediments at the sulfate reduction-methane production boundary and is probably performed by archaea working in syntrophic co-operation with sulfate-reducing bacteria. Diagnostic lipid biomarkers of archaeal origin include irregular isoprenoids such as 2,6,11,15-tetramethylhexadecane (crocetane) and 2,6,10,15,19-pentamethylicosane (PMI) as well as the glycerol ether lipid archaeol (2,3-di-O-phytanyl-sn-glycerol). These biomarkers are prominent lipid constituents in the anaerobic sediments as well as in the carbonate precipitates. Carbon isotopic compositions of the biomarkers are strongly depleted in 13C with values of δ13C as low as −130.3‰ PDB. The process of anaerobic methane oxidation is also reflected in the carbon isotope composition of organic matter ...
The anaerobic oxidation of methane (AOM) is a globally significant sink that regulates methane flux from sediments into the oceans and atmosphere. Here we examine mesophilic to thermophilic AOM in hydrothermal sediments recovered from the Middle Valley vent field, on the Juan de Fuca Ridge. Using continuous-flow sediment bioreactors and batch incubations, we characterized (i) the degree to which AOM contributes to net dissolved inorganic carbon flux, (ii) AOM and sulfate reduction (SR) rates as a function of temperature and (iii) the distribution and density of known anaerobic methanotrophs (ANMEs). In sediment bioreactors, inorganic carbon stable isotope mass balances results indicated that AOM accounted for between 16% and 86% of the inorganic carbon produced, underscoring the role of AOM in governing inorganic carbon flux from these sediments. At 90°C, AOM occurred in the absence of SR, demonstrating a striking decoupling of AOM from SR. An abundance of Fe(III)-bearing minerals resembling ...
United States Geological Survey, Florida Integrated Science Center, Saint Petersburg (Terrestrial, Freshwater, and Marine Ecosystems Program),United States Army Corps of Engineers,Everglades National Park. Chief Scientists: Tom Smith, Gordon Anderson, Karen Balentine. Sampling of sediment surface elevation tables data of field activity 08LME02 (E-2-08-FL) in Everglades National Park, Florida, Ten Thousand Islands National Wildlife Refuge from 10/01/2008 to 09/30/2008, ,http://walrus.wr.usgs.gov/infobank/e/e208fl/html/e-2-08-fl.meta.html, ...
Gas-hydrate-bearing sand-core samples have been obtained from the Canadian Mallik wells, and the Nankai Trough wells of offshore Japan. The chloride-content anomalies in extracted pore waters, core-temperature depression, core observations, and visible gas hydrates, as well as continuous down-hole well-log data, confirm the presence of pore-space hydrateas an intergranular pore filling within sandy layers, clarifying the characteristics of subsurface natural gas hydrate in marine and permafrost zones. Gas-hydrate saturations (percent of pore volume) as high as 80% have been measured, which requires enough original pore space in the host sediment to allow the gas to accumulate. Carbon and hydrogen isotopic compositions of methane and hydrocarbon compositions in gas hydrate and gas-hydrate-bearing shallow sediments in the Nankai Trough show that methane is generated by microbial reduction of CO2 and suggest progressive decreases in microbial (biogenic) activity with depth and upward gas migration ...
In the present study, effect-directed analysis was used to identify teratogenic compounds in porewater collected from a Superfund site along the Elizabeth River estuary (VA, USA). Zebrafish (Danio rerio) exposed to the porewater displayed acute developmental toxicity and cardiac teratogenesis, presumably because of elevated sediment levels of polycyclic aromatic hydrocarbons (PAHs) from historical creosote use. Pretreatment of porewater with several physical and chemical particle removal methods revealed that colloid-bound chemicals constituted the bulk of the observed toxicity. Size-exclusive chromatography and normal-phase high-performance liquid chromatography were used to fractionate Elizabeth River porewater. Acute toxicity of porewater extracts and extract fractions was assessed as the pericardial area in embryonic zebrafish. The most toxic fraction contained several known aryl hydrocarbon receptor (AhR) agonists (e.g., 1,2-benzofluorene and 1,2-benzanthracene) and cytochrome P450 A1 ...
It has previously been demonstrated that [14C]-labeled polycyclic aromatic hydrocarbons (PAHs) can be oxidized to 14CO2 in anoxic, PAH-contaminated, marine harbor sediments in which sulfate reduction is the terminal electron-accepting process. However, it has not previously been determined whether t …
We compared the burial efficiency of organic carbon (buried OC: deposited OC) in a diverse set of 27 different sediments from 11 lakes, focusing on the potential effects of organic matter source, oxygen exposure, and protective sorption of OC onto mineral surfaces. Average OC burial efficiency was high (mean 48%), and it was particularly high in sediments receiving high input of allochthonous organic matter (mean 67%). Further, OC burial efficiency was strongly negatively related to the oxygen exposure time, again particularly so in sediments receiving high allochthonous loads. On the other hand, OC burial efficiency was not related to the mineral surface area, which was used as a proxy of the sorption capacity of the mineral phase for OC. The high OC burial efficiency in many lake sediments can thus be attributed to the frequent and significant input of allochthonous organic matter to lakes, as well as to a strong dependence of OC burial efficiency on oxygen exposure time. This study ...
Surficial geologic mapping of the Arctic Ocean was undertaken to provide a basis for understanding different geologic environments in this polar setting. Mapping was based on data acquired from numerous icebreaker and submarine missions to the polar region. The intent was to create a geologic layer overlying the International Bathymetric Chart of the Arctic Ocean. Analysis of subbottom profiler and multibeam bathymetric data in conjunction with sediment cores and the regional morphology rendered from the IBCAO data were used to map different surficial geologic units. For a relatively small ocean basin, the Arctic Ocean reveals a plethora of margin and basin types reflecting both the complex tectonic origins of the basin and its diverse sedimentation history. Broad and narrow shelves were subjected to a complex ice-margin history in the Quaternary, and bear the sediment types and morphological features as a result. Some shelfal areas are heavily influenced by rivers. Extensive deep water ridges and
Most sulfate-reducing microorganisms (SRM) present in subsurface marine sediments belong to uncultured groups only distantly related to known SRM and it remains unclear how changing geochemical zones and sediment depth influence their community structure. We mapped the community composition and abundance of SRM by amplicon-sequencing and quantifying dsrB, which encodes dissimilatory sulfite reductase subunit beta, in sediment samples covering different vertical geochemical zones ranging from the surface sediment to the deep sulfate-depleted subsurface at four locations in Aarhus Bay, Denmark. SRM were present in all geochemical zones including sulfate-depleted methanogenic sediment. The biggest shift in SRM community composition and abundance occurring across the transition from bioturbated surface sediments into non-bioturbated sediments below, where redox fluctuations and input of fresh organic matter due to macrofaunal activity are absent. SRM abundance correlated with sulfate reduction rates ...
Current set contains data on the molecular composition of lignin derived phenols and organic carbon content in bottom sediments and subsea permafrost rocks from five sediment cores obtained in the Buor-Khaya Bay (Laptev Sea). The substantially irregular distribution of lignin concentration and lignin-based molecular proxies revealed in the investigated samples reflect drastic environmental and depositional changes in the study area of the Laptev Sea. The increased OC content (2-5%) at some horizons and the highest concentrations (up to 23%) are related to the presence of vegetable residues such as wood and moss. Riverine flux and coastal thermoabrasion are considerable in lignin supply. Vanillyl and syringyl phenols dominate the lignin pool. Gymnosperm wood accounts for a significant fraction of the lignin. Concentration of lignin in sediments varies in five orders of magnitude. Strong share of lignin consists of biochemically unaltered compounds. Distribution of specific lignin phenols and related
Methane (CH4) flux to the atmosphere is mitigated via microbial CH4 oxidation in sediments and water. As arctic temperaturesincrease, understanding the effects of temperature on the activity and identity of methanotrophs in arctic lake sediments is importantto predicting future CH4 emissions. We used DNA-based stable-isotope probing (SIP), quantitative PCR (Q-PCR), andpyrosequencing analyses to identify and characterize methanotrophic communities active at a range of temperatures (4°C, 10°C,and 21°C) in sediments (to a depth of 25 cm) sampled from Lake Qalluuraq on the North Slope of Alaska. CH4 oxidation activitywas measured in microcosm incubations containing sediments at all temperatures, with the highest CH4 oxidation potential of37.5 mol g1 day1 in the uppermost (depth, 0 to 1 cm) sediment at 21°C after 2 to 5 days of incubation. Q-PCR of pmoA and ofthe 16S rRNA genes of type I and type II methanotrophs, and pyrosequencing of 16S rRNA genes in 13C-labeled DNA obtained bySIP demonstrated ...
Particle Size of River Sediments. The relationships between particle size of river sediments and the variation in stream discharge are studied. The results of a study carried out to determine the variation of both bed material and suspended sediment particle size for differing flow conditions is presented. A significant finding is presented which shows that the particle size of suspended and bed sediments remains relatively constant with variation in stream discharge. This condition was found from the analysis of results at four river sections on three rivers in Scotland and was also corroborated by results from research in the United States. Conclusions are presented which attempt to explain these findings in terms of the availability of material for transport by streams rather than on purely hydraulic considerations.
Water radiolysis continuously produces H2 and oxidized chemicals in wet sediment and rock. Radiolytic H2 has been identified as the primary electron donor (food) for microorganisms in continental aquifers kilometers below Earths surface. Radiolytic products may also be significant for sustaining life in subseafloor sediment and subsurface environments of other planets. However, the extent to which most subsurface ecosystems rely on radiolytic products has been poorly constrained, due to incomplete understanding of radiolytic chemical yields in natural environments. Here we show that all common marine sediment types catalyse radiolytic H2 production, amplifying yields by up to 27X relative to pure water. In electron equivalents, the global rate of radiolytic H2 production in marine sediment appears to be 1-2% of the global organic flux to the seafloor. However, most organic matter is consumed at or near the seafloor, whereas radiolytic H2 is produced at all sediment depths. Comparison of radiolytic H2
Data & statistics on Particle size distribution of sediments from South West Spit: Particle size distribution of sediments from South West Spit, Particle Size Distribution (psd) of sediment particles, Sieve sizes used for sediment particle distribution and the Wentworth sediment size categories (Buchanan 1984) Sieve Number...
Wang, N., Consbrock, R. A., Ingersoll, C. G. and Barnhart, M. C. (2011), Evaluation of influence of sediment on the sensitivity of a unionid mussel (Lampsilis siliquoidea) to ammonia in 28-day water exposures. Environmental Toxicology and Chemistry, 30: 2270-2276. doi: 10.1002/etc.616 ...
In this study, redox-dependent phosphorus (P) recycling and burial at 6 sites in the Baltic Sea is investigated using a combination of porewater and sediment analyses and sediment age dating (Pb-210 and Cs-117). We focus on sites in the Kattegat, Danish Straits and Baltic Proper where present-day bottom water redox conditions range from fully oxygenated and seasonally hypoxic to almost permanently anoxic and sulfidic. Strong surface enrichments of Fe-oxide bound P are observed at oxic and seasonally hypoxic sites but not in the anoxic basins. Reductive dissolution of Fe-oxides and release of the associated P supports higher sediment-water exchange of PO4 at hypoxic sites (up to similar to 800 mu mol P m(-2) d(-1)) than in the anoxic basins. This confirms that Fe-bound P in surface sediments in the Baltic acts as a major internal source of P during seasonal hypoxia, as suggested previously from water column studies. Most burial of P takes place as organic P. We find no evidence for significant ...
Sediment is not a sedimentary rock unless the little grains become stuck together. The material that holds sediment together into a rock is called cement. Cement is mineral that forms when seawater or groundwater travels through the empty spaces between sediment. If the water contains the chemicals that are needed, mineral crystals will form in-between the sediment. The mineral holds the sediment together. Minerals like calcite, quartz, and sometimes hematite form the cement in sedimentary rocks. A pile of sediment becomes a sedimentary rock more quickly when it is buried deep underground. This makes the sediment grains become squished closely together. However, the whole process can take tens to hundreds of thousands of years.. ...
The degradation of organic matter in the deep-sea is a critical microbial process that facilitates global carbon cycling and affects all organisms. Typically, deep-sea microbial communities experience very low organic carbon availability, however, at deep-sea whalefalls these bacteria are provided with organic carbon levels ~2000x greater than usual. This creates an ideal environment in which to examine the metabolism of marine microbes and to further understand carbon cycling on and within the deep-sea floor. Only a handful of papers have investigated marine sediments, thus, we first had to develop a method for measuring enzymatic activity. We focused on proteases, enzymes responsible for the breakdown of proteins, one of a number of organic carbon sources in the environment. Protease activity was measured in marine sediments associated with a whalefall at 1800 meters depth in Monterey Bay, collected at zero, three and ten meters distance. As expected, the highest protease activity was found ...
Heavy metal content in relation to particle size and organic content of surficial sediments in Miami River and transport potential Article ...
Abstract. Thaumarchaeota are amongst the most abundant microorganisms in aquatic environments, however, their metabolism in marine sediments is still debated. Labeling studies in marine sediments have previously been undertaken, but focused on complex organic carbon substrates which Thaumarchaeota have not yet been shown to take up. In this study, we investigated the activity of Thaumarchaeota in sediments by supplying different 13C-labeled substrates which have previously been shown to be incorporated into archaeal cells in water incubations and/or enrichment cultures. We determined the incorporation of 13C-label from bicarbonate, pyruvate, glucose and amino acids into thaumarchaeal intact polar lipid-glycerol dibiphytanyl glycerol tetraethers (IPL-GDGTs) during 4-6 day incubations of marine sediment cores from three sites on the Iceland shelf. Thaumarchaeal intact polar lipids, in particular crenarchaeol, were detected at all stations and concentrations remained constant or decreased slightly ...
Mass-transport deposits reveal something of the timing, source areas and depositional processes that contributed to the evolution of the New Jersey continental margin. Many of the mass-transport deposits rest upon prominent stratal surfaces and sequence boundaries permitting evaluation of the relationship between mass wasting and eustatic change. Five distinct mass-transport facies representative of intercanyon regions of the slope, canyons and continental rise settings are recognized in the Ocean Drilling Program Leg 150 Sites (902-906). These mass-transport deposits consist predominantly of muddy slumps and debris flows, and to a lesser extent sandy mass flows and gravity-related flows. The styles of soft-sediment deformation, mineralogy, and biostratigraphy of these mass-transport deposits provide new information on the mass-wasting history of the continental margin. At intercanyon sites beneath the continental slope (Sites 902-904), mud with disseminated sand occurs mainly at sequence ...
Two Gram-staining-positive, strictly aerobic bacilli, designated as strains Ma50-5T and Ma50-6T, were isolated from the hydrothermal sediments of Manus Basin in the western Pacific Ocean. Based on 16S rRNA gene sequence, strains Ma50-5T and Ma50-6T were most closely related to Bacillus alveayuensis (97.0 and 97.2 % identity, respectively). The 16S rRNA gene sequence identity between strains Ma50-5T and Ma50-6T was 97.4 %. The identities between strains Ma50-5T and Ma50-6T and other closely related organisms were below 97.0 %. The G+C contents of the genomic DNA of strains Ma50-5T and Ma50-6T were 43.4 and 47.6 mol%, respectively. The major fatty acids (>10 %) of both strains were iso-C15 : 0 and iso-C17 : 0. The predominant isoprenoid quinone detected in both strains was menaquinone-7. Phylogenetic, physiological, biochemical and morphological analyses suggested that strains Ma50-5T and Ma50-6T represent two novel species of the genus Bacillus , for which the names Bacillus kexueae sp. nov. (type
The seafloor is a unique environment, which allows insights into how geochemical processes affect the diversity of biological life. Among its diverse ecosystems are deep-sea brine pools - water bodies characterized by a unique combination of extreme conditions. The polyextremophiles that constitute the microbial assemblage of these deep hot brines have not been comprehensively studied. We report a comparative taxonomic analysis of the prokaryotic communities of the sediments directly below the Red Sea brine pools, namely, Atlantis II, Discovery, Chain Deep, and an adjacent brine-influenced site. Analyses of sediment samples and high-throughput pyrosequencing of PCR-amplified environmental 16S ribosomal RNA genes (16S rDNA) revealed that one sulfur (S)-rich Atlantis II and one nitrogen (N)-rich Discovery Deep section contained distinct microbial populations that differed from those found in the other sediment samples examined. Proteobacteria, Actinobacteria, Cyanobacteria, Deferribacteres, and ...
Knowledge of fine sediment delivery (both timing and loading) is fundamental to the assessment of non-point source pollution in estuarine environments. This study comprised three key components that led to the development of a fine sediment and particulate associated phosphorus budget in a typical agricultural estuary. Firstly, to explore catchment inputs, turbidity and flow were monitored continuously upstream of the freshwater/saline interface on the main stem channel of the south Devon River Avon, which drains a medium sized agricultural catchment (area 340 km2), in southwest UK. Thirty-five storms were studied in detail; and the hydrological and suspended sediment load response was observed to be highly variable. Suspended sediment concentrations (SSC) reached a maximum of 804 mg L-1 and sediment load varied from 3 to 227 t per hydrological event. Most sediment load was concentrated in winter months when competent flows occur frequently. Hydrological response was also variable in terms of ...
The main purpose of this study was to examine the effect on a lake as a result of sulfide mining. The mining industry leads to problems with acid mine drainage and leaching of heavy metals. This study examines concentrations of lead, copper, zinc and arsenic in the sediment of Lake Storjuktan close to the Blaikenmine. The main objective was to compare concentrations before mining operations started 2006 with samples from the same sediment basin 2015. Cores (n=2) was taken upstream and downstream the mining site at the same coordinates. To reveal spatial variations in concentrations six more sediment samples were taken. I found that; i) zinc concentration was distinctively higher in the surface sediment sampled in 2015 than 2006 while lead, copper and arsenic showed small to insignificant changes; ii) approximately an area of 22 hectare anthropogenic sediment has formed within Storjuktan with extremely high concentrations of zinc and high concentrations of lead and copper. In the latter case, the ...
Article Abundances, Depositional Fluxes, and Homologue Patterns of Polychlorinated Biphenyls in Dated Sediment Cores from the Pearl River Delta, China. Despite the recent efforts to investigate the distribution and fate of persistent organic pollutan...
Foraminifera are single-celled eukaryotes (protists) of large ecological importance, as well as environmental and paleoenvironmental indicators and biostratigraphic tools. In addition, they are capable of surviving in anoxic marine environments where they represent a major component of the benthic community. However, the cellular adaptations of Foraminifera to the anoxic environment remain poorly constrained. We sampled an oxic-anoxic transition zone in marine sediments from the Namibian shelf, where the genera Bolivina and Stainforthia dominated the Foraminifera community, and use metatranscriptomics to characterize Foraminifera metabolism across the different geochemical conditions. Relative Foraminifera gene expression in anoxic sediment increased an order of magnitude, which was confirmed in a 10-day incubation experiment where the development of anoxia coincided with a 20-40-fold increase in the relative abundance of Foraminifera protein encoding transcripts, attributed primarily to those involved
Sediment Transport and Diffusion: Columbia Estuary and Entrance. Review of past studies and investigations, including prototype measurements and hydraulic model tests; reveal some indications of sediment transport and diffusion in the vicinity of the Columbia Estuary and Entrance. These indications reveal a unique pattern of sediment transport and diffusion prevailing in this region. This leads to the conclusion that the estuary is acting as a trap for collection of bottom sediments and that, immediately offshore, the forces of erosion and accretion have established a regime that is also worthy of detailed further study.
In order to find the effect of intertidal sediments on nutrient cycle in coastal environment, we measured ammonia, nitrate, phosphate, and silicate concentrations every hour during at least 12 hours in the entrance of Keunso Bay during four seasons. The content of ammonia and silicate do not change considerably with season, but nitrate shows large seasonal variation. In summer, nitrate concentration was much lower than in other seasons, which resulted from large biological uptake and active denitrification in intertidal sediments during summer. Phosphate also exhibit seasonal variations, but not that large like nitrate. N/P and N/Si ratios were lower in summer than in other seasons, which was due to active denitrification in the intertidal sediments during summer. For all seasons, ammonia concentrations were higher at low tide than at high tide, but nitrate concentrations were higher at high tide. Dissolved inorganic nitrogen concentrations measured in spring, summer, and winter were higher at high