Geologic Sediments: A mass of organic or inorganic solid fragmented material, or the solid fragment itself, that comes from the weathering of rock and is carried by, suspended in, or dropped by air, water, or ice. It refers also to a mass that is accumulated by any other natural agent and that forms in layers on the earth's surface, such as sand, gravel, silt, mud, fill, or loess. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1689)Seawater: The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.Fresh Water: Water containing no significant amounts of salts, such as water from RIVERS and LAKES.Water Microbiology: The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.RNA, Ribosomal, 16S: Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.Water Pollutants, Chemical: Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.Rivers: Large natural streams of FRESH WATER formed by converging tributaries and which empty into a body of water (lake or ocean).DNA, Ribosomal: DNA sequences encoding RIBOSOMAL RNA and the segments of DNA separating the individual ribosomal RNA genes, referred to as RIBOSOMAL SPACER DNA.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Bacteria: One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.Methane: The simplest saturated hydrocarbon. It is a colorless, flammable gas, slightly soluble in water. It is one of the chief constituents of natural gas and is formed in the decomposition of organic matter. (Grant & Hackh's Chemical Dictionary, 5th ed)Biodegradation, Environmental: Elimination of ENVIRONMENTAL POLLUTANTS; PESTICIDES and other waste using living organisms, usually involving intervention of environmental or sanitation engineers.Deltaproteobacteria: A group of PROTEOBACTERIA represented by morphologically diverse, anaerobic sulfidogens. Some members of this group are considered bacterial predators, having bacteriolytic properties.Sulfur-Reducing Bacteria: A group of gram-negative, anaerobic bacteria that is able to oxidize acetate completely to carbon dioxide using elemental sulfur as the electron acceptor.Archaea: One of the three domains of life (the others being BACTERIA and Eukarya), formerly called Archaebacteria under the taxon Bacteria, but now considered separate and distinct. They are characterized by: (1) the presence of characteristic tRNAs and ribosomal RNAs; (2) the absence of peptidoglycan cell walls; (3) the presence of ether-linked lipids built from branched-chain subunits; and (4) their occurrence in unusual habitats. While archaea resemble bacteria in morphology and genomic organization, they resemble eukarya in their method of genomic replication. The domain contains at least four kingdoms: CRENARCHAEOTA; EURYARCHAEOTA; NANOARCHAEOTA; and KORARCHAEOTA.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Estuaries: A partially enclosed body of water, and its surrounding coastal habitats, where saltwater from the ocean mixes with fresh water from rivers or streams. The resulting mixture of seawater and fresh water is called brackish water and its salinity can range from 0.5 to 35 ppt. (accessed http://oceanservice.noaa.gov/education/kits/estuaries/estuaries01_whatis.html)Oceans and Seas: A great expanse of continuous bodies of salt water which together cover more than 70 percent of the earth's surface. Seas may be partially or entirely enclosed by land, and are smaller than the five oceans (Atlantic, Pacific, Indian, Arctic, and Antarctic).DNA, Archaeal: Deoxyribonucleic acid that makes up the genetic material of archaea.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Ecosystem: A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)Lakes: Inland bodies of still or slowly moving FRESH WATER or salt water, larger than a pond, and supplied by RIVERS and streams.Genes, rRNA: Genes, found in both prokaryotes and eukaryotes, which are transcribed to produce the RNA which is incorporated into RIBOSOMES. Prokaryotic rRNA genes are usually found in OPERONS dispersed throughout the GENOME, whereas eukaryotic rRNA genes are clustered, multicistronic transcriptional units.Water Pollution, Chemical: Adverse effect upon bodies of water (LAKES; RIVERS; seas; groundwater etc.) caused by CHEMICAL WATER POLLUTANTS.Pacific OceanRhizophoraceae: A plant family of the order Rhizophorales, subclass Rosidae, class Magnoliopsida, that includes mangrove trees.Biodiversity: The variety of all native living organisms and their various forms and interrelationships.Soil Microbiology: The presence of bacteria, viruses, and fungi in the soil. This term is not restricted to pathogenic organisms.Anaerobiosis: The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Water Pollutants: Substances or organisms which pollute the water or bodies of water. Use for water pollutants in general or those for which there is no specific heading.Wetlands: Environments or habitats at the interface between truly terrestrial ecosystems and truly aquatic systems making them different from each yet highly dependent on both. Adaptations to low soil oxygen characterize many wetland species.Uranium: Uranium. A radioactive element of the actinide series of metals. It has an atomic symbol U, atomic number 92, and atomic weight 238.03. U-235 is used as the fissionable fuel in nuclear weapons and as fuel in nuclear power reactors.Water Pollution: Contamination of bodies of water (such as LAKES; RIVERS; SEAS; and GROUNDWATER.)Environmental Monitoring: The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.Base Composition: The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.Geology: The science of the earth and other celestial bodies and their history as recorded in the rocks. It includes the study of geologic processes of an area such as rock formations, weathering and erosion, and sedimentation. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Sulfates: Inorganic salts of sulfuric acid.Arctic Regions: The Arctic Ocean and the lands in it and adjacent to it. It includes Point Barrow, Alaska, most of the Franklin District in Canada, two thirds of Greenland, Svalbard, Franz Josef Land, Lapland, Novaya Zemlya, and Northern Siberia. (Webster's New Geographical Dictionary, 1988, p66)Eutrophication: The enrichment of a terrestrial or aquatic ECOSYSTEM by the addition of nutrients, especially nitrogen and phosphorus, that results in a superabundant growth of plants, ALGAE, or other primary producers. It can be a natural process or result from human activity such as agriculture runoff or sewage pollution. In aquatic ecosystems, an increase in the algae population is termed an algal bloom.Bacteria, AnaerobicRNA, Bacterial: Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.Water Pollutants, Radioactive: Pollutants, present in water or bodies of water, which exhibit radioactivity.Gammaproteobacteria: A group of the proteobacteria comprised of facultatively anaerobic and fermentative gram-negative bacteria.Aroclors: Industrial chemicals which have become widespread environmental pollutants. Each aroclor is a mixture of chlorinated biphenyls (1200 series) or chlorinated terphenyls (5400 series) or a combination of both (4400 series).Soil Pollutants: Substances which pollute the soil. Use for soil pollutants in general or for which there is no specific heading.Water Movements: The flow of water in enviromental bodies of water such as rivers, oceans, water supplies, aquariums, etc. It includes currents, tides, and waves.Polycyclic Hydrocarbons, Aromatic: A major group of unsaturated cyclic hydrocarbons containing two or more rings. The vast number of compounds of this important group, derived chiefly from petroleum and coal tar, are rather highly reactive and chemically versatile. The name is due to the strong and not unpleasant odor characteristic of most substances of this nature. (From Hawley's Condensed Chemical Dictionary, 12th ed, p96)Oxidation-Reduction: A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).Biota: The spectrum of different living organisms inhabiting a particular region, habitat, or biotope.Petroleum: Naturally occurring complex liquid hydrocarbons which, after distillation, yield combustible fuels, petrochemicals, and lubricants.Groundwater: Liquid water present beneath the surface of the earth.Bays: An area of water mostly surrounded by land, usually smaller than a gulf, and affording access to the sea.Sulfides: Chemical groups containing the covalent sulfur bonds -S-. The sulfur atom can be bound to inorganic or organic moieties.Humic Substances: Organic matter in a state of advanced decay, after passing through the stages of COMPOST and PEAT and before becoming lignite (COAL). It is composed of a heterogenous mixture of compounds including phenolic radicals and acids that polymerize and are not easily separated nor analyzed. (E.A. Ghabbour & G. Davies, eds. Humic Substances, 2001).Marine Biology: The study of the origin, structure, development, growth, function, genetics, and reproduction of organisms which inhabit the OCEANS AND SEAS.Carbon: A nonmetallic element with atomic symbol C, atomic number 6, and atomic weight [12.0096; 12.0116]. It may occur as several different allotropes including DIAMOND; CHARCOAL; and GRAPHITE; and as SOOT from incompletely burned fuel.Paleontology: The study of early forms of life through fossil remains.Metals, Heavy: Metals with high specific gravity, typically larger than 5. They have complex spectra, form colored salts and double salts, have a low electrode potential, are mainly amphoteric, yield weak bases and weak acids, and are oxidizing or reducing agents (From Grant & Hackh's Chemical Dictionary, 5th ed)Crenarchaeota: A kingdom in the domain ARCHAEA comprised of thermoacidophilic, sulfur-dependent organisms. The two orders are SULFOLOBALES and THERMOPROTEALES.Foraminifera: An order of amoeboid EUKARYOTES characterized by reticulating pseudopods and a complex life cycle with an alternation of generations. Most are less than 1mm in size and found in marine or brackish water.Proteobacteria: A phylum of bacteria consisting of the purple bacteria and their relatives which form a branch of the eubacterial tree. This group of predominantly gram-negative bacteria is classified based on homology of equivalent nucleotide sequences of 16S ribosomal RNA or by hybridization of ribosomal RNA or DNA with 16S and 23S ribosomal RNA.Fatty Acids: Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)Antarctic Regions: The continent lying around the South Pole and the southern waters of the Atlantic, Pacific, and Indian Oceans. It includes the Falkland Islands Dependencies. (From Webster's New Geographical Dictionary, 1988, p55)Thiotrichaceae: A family of colorless sulfur bacteria in the order Thiotrichales, class GAMMAPROTEOBACTERIA.Bacterial Typing Techniques: Procedures for identifying types and strains of bacteria. The most frequently employed typing systems are BACTERIOPHAGE TYPING and SEROTYPING as well as bacteriocin typing and biotyping.Soil: The unconsolidated mineral or organic matter on the surface of the earth that serves as a natural medium for the growth of land plants.HydrocarbonsChlorophenols: Phenols substituted with one or more chlorine atoms in any position.

Desulfocella halophila gen. nov., sp. nov., a halophilic, fatty-acid-oxidizing, sulfate-reducing bacterium isolated from sediments of the Great Salt Lake. (1/2414)

A new halophilic sulfate-reducing bacterium, strain GSL-But2T, was isolated from surface sediment of the Southern arm of the Great Salt Lake, UT, USA. The organism grew with a number of straight-chain fatty acids (C4-C16), 2-methylbutyrate, L-alanine and pyruvate as electron donors. Butyrate was oxidized incompletely to acetate. Sulfate, but not sulfite or thiosulfate, served as an electron acceptor. Growth was observed between 2 and 19% (w/v) NaCl with an optimum at 4-5% (w/v) NaCl. The optimal temperature and pH for growth were around 34 degrees C and pH 6.5-7.3, respectively. The generation time under optimal conditions in defined medium was around 28 h, compared to 20 h in complex medium containing yeast extract. The G+C content was 35.0 mol%. 16S rRNA gene sequence analysis revealed that strain GSL-But2T belongs to the family Desulfobacteriaceae within the delta-subclass of the Proteobacteria and suggested that strain GSL-But2T represents a member of a new genus. The name Desulfocella halophila gen. nov., sp. nov. is proposed for this organism. The type strain of D. halophila is strain GSL-But2T (= DSM 11763T = ATCC 700426T).  (+info)

Isolation from estuarine sediments of a Desulfovibrio strain which can grow on lactate coupled to the reductive dehalogenation of 2,4, 6-tribromophenol. (2/2414)

Strain TBP-1, an anaerobic bacterium capable of reductively dehalogenating 2,4,6-tribromophenol to phenol, was isolated from estuarine sediments of the Arthur Kill in the New York/New Jersey harbor. It is a gram-negative, motile, vibrio-shaped, obligate anaerobe which grows on lactate, pyruvate, hydrogen, and fumarate when provided sulfate as an electron acceptor. The organism accumulates acetate when grown on lactate and sulfate, contains desulfoviridin, and will not grow in the absence of NaCl. It will not utilize acetate, succinate, propionate, or butyrate for growth via sulfate reduction. When supplied with lactate as an electron donor, strain TBP-1 will utilize sulfate, sulfite, sulfur, and thiosulfate for growth but not nitrate, fumarate, or acrylate. This organism debrominates 2-, 4-, 2,4-, 2,6-, and 2,4,6-bromophenol but not 3- or 2,3-bromophenol or monobrominated benzoates. It will not dehalogenate monochlorinated, fluorinated, or iodinated phenols or chlorinated benzoates. Together with its physiological characteristics, its 16S rRNA gene sequence places it in the genus Desulfovibrio. The average growth yield of strain TBP-1 grown on a defined medium supplemented with lactate and 2,4,6-bromophenol is 3.71 mg of protein/mmol of phenol produced, and the yield was 1.42 mg of protein/mmol of phenol produced when 4-bromophenol was the electron acceptor. Average growth yields (milligrams of protein per millimole of electrons utilized) for Desulfovibrio sp. strain TBP-1 grown with 2,4,6-bromophenol, 4-bromophenol, or sulfate are 0.62, 0.71, and 1.07, respectively. Growth did not occur when either lactate or 2,4,6-bromophenol was omitted from the growth medium. These results indicate that Desulfovibrio sp. strain TBP-1 is capable of growth via halorespiration.  (+info)

Diversity of nitrous oxide reductase (nosZ) genes in continental shelf sediments. (3/2414)

Diversity of the nitrous oxide reductase (nosZ) gene was examined in sediments obtained from the Atlantic Ocean and Pacific Ocean continental shelves. Approximately 1,100 bp of the nosZ gene were amplified via PCR, using nosZ gene-specific primers. Thirty-seven unique copies of the nosZ gene from these marine environments were characterized, increasing the nosZ sequence database fourfold. The average DNA similarity for comparisons between all 49 variants of the nosZ gene was 64% +/- 10%. Alignment of the derived amino acid sequences confirmed the conservation of important structural motifs. A highly conserved region is proposed as the copper binding, catalytic site (CuZ) of the mature protein. Phylogenetic analysis demonstrated three major clusters of nosZ genes, with little overlap between environmental and culture-based groups. Finally, the two non-culture-based gene clusters generally corresponded to sampling location, implying that denitrifier communities may be restricted geographically.  (+info)

Dense populations of a giant sulfur bacterium in Namibian shelf sediments. (4/2414)

A previously unknown giant sulfur bacterium is abundant in sediments underlying the oxygen minimum zone of the Benguela Current upwelling system. The bacterium has a spherical cell that exceeds by up to 100-fold the biovolume of the largest known prokaryotes. On the basis of 16S ribosomal DNA sequence data, these bacteria are closely related to the marine filamentous sulfur bacteria Thioploca, abundant in the upwelling area off Chile and Peru. Similar to Thioploca, the giant bacteria oxidize sulfide with nitrate that is accumulated to +info)

Environment and behavior of 2.5-million-year-old Bouri hominids. (5/2414)

The Hata Member of the Bouri Formation is defined for Pliocene sedimentary outcrops in the Middle Awash Valley, Ethiopia. The Hata Member is dated to 2.5 million years ago and has produced a new species of Australopithecus and hominid postcranial remains not currently assigned to species. Spatially associated zooarchaeological remains show that hominids acquired meat and marrow by 2.5 million years ago and that they are the near contemporary of Oldowan artifacts at nearby Gona. The combined evidence suggests that behavioral changes associated with lithic technology and enhanced carnivory may have been coincident with the emergence of the Homo clade from Australopithecus afarensis in eastern Africa.  (+info)

Rhodococcus erythropolis DCL14 contains a novel degradation pathway for limonene. (6/2414)

Strain DCL14, which is able to grow on limonene as a sole source of carbon and energy, was isolated from a freshwater sediment sample. This organism was identified as a strain of Rhodococcus erythropolis by chemotaxonomic and genetic studies. R. erythropolis DCL14 also assimilated the terpenes limonene-1,2-epoxide, limonene-1,2-diol, carveol, carvone, and (-)-menthol, while perillyl alcohol was not utilized as a carbon and energy source. Induction tests with cells grown on limonene revealed that the oxygen consumption rates with limonene-1,2-epoxide, limonene-1,2-diol, 1-hydroxy-2-oxolimonene, and carveol were high. Limonene-induced cells of R. erythropolis DCL14 contained the following four novel enzymatic activities involved in the limonene degradation pathway of this microorganism: a flavin adenine dinucleotide- and NADH-dependent limonene 1, 2-monooxygenase activity, a cofactor-independent limonene-1, 2-epoxide hydrolase activity, a dichlorophenolindophenol-dependent limonene-1,2-diol dehydrogenase activity, and an NADPH-dependent 1-hydroxy-2-oxolimonene 1,2-monooxygenase activity. Product accumulation studies showed that (1S,2S,4R)-limonene-1,2-diol, (1S, 4R)-1-hydroxy-2-oxolimonene, and (3R)-3-isopropenyl-6-oxoheptanoate were intermediates in the (4R)-limonene degradation pathway. The opposite enantiomers [(1R,2R,4S)-limonene-1,2-diol, (1R, 4S)-1-hydroxy-2-oxolimonene, and (3S)-3-isopropenyl-6-oxoheptanoate] were found in the (4S)-limonene degradation pathway, while accumulation of (1R,2S,4S)-limonene-1,2-diol from (4S)-limonene was also observed. These results show that R. erythropolis DCL14 metabolizes both enantiomers of limonene via a novel degradation pathway that starts with epoxidation at the 1,2 double bond forming limonene-1,2-epoxide. This epoxide is subsequently converted to limonene-1,2-diol, 1-hydroxy-2-oxolimonene, and 7-hydroxy-4-isopropenyl-7-methyl-2-oxo-oxepanone. This lactone spontaneously rearranges to form 3-isopropenyl-6-oxoheptanoate. In the presence of coenzyme A and ATP this acid is converted further, and this finding, together with the high levels of isocitrate lyase activity in extracts of limonene-grown cells, suggests that further degradation takes place via the beta-oxidation pathway.  (+info)

Role of methanogens and other bacteria in degradation of dimethyl sulfide and methanethiol in anoxic freshwater sediments. (7/2414)

The roles of several trophic groups of organisms (methanogens and sulfate- and nitrate-reducing bacteria) in the microbial degradation of methanethiol (MT) and dimethyl sulfide (DMS) were studied in freshwater sediments. The incubation of DMS- and MT-amended slurries revealed that methanogens are the dominant DMS and MT utilizers in sulfate-poor freshwater systems. In sediment slurries, which were depleted of sulfate, 75 micromol of DMS was stoichiometrically converted into 112 micromol of methane. The addition of methanol or MT to DMS-degrading slurries at concentrations similar to that of DMS reduced DMS degradation rates. This indicates that the methanogens in freshwater sediments, which degrade DMS, are also consumers of methanol and MT. To verify whether a competition between sulfate-reducing and methanogenic bacteria for DMS or MT takes place in sulfate-rich freshwater systems, the effects of sulfate and inhibitors, like bromoethanesulfonic acid, molybdate, and tungstate, on the degradation of MT and DMS were studied. The results for these sulfate-rich and sulfate-amended slurry incubations clearly demonstrated that besides methanogens, sulfate-reducing bacteria take part in MT and DMS degradation in freshwater sediments, provided that sulfate is available. The possible involvement of an interspecies hydrogen transfer in these processes is discussed. In general, our study provides evidence for methanogenesis as a major sink for MT and DMS in freshwater sediments.  (+info)

Molecular analysis of microbial community structures in pristine and contaminated aquifers: field and laboratory microcosm experiments. (8/2414)

This study used phylogenetic probes in hybridization analysis to (i) determine in situ microbial community structures in regions of a shallow sand aquifer that were oxygen depleted and fuel contaminated (FC) or aerobic and noncontaminated (NC) and (ii) examine alterations in microbial community structures resulting from exposure to toluene and/or electron acceptor supplementation (nitrate). The latter objective was addressed by using the NC and FC aquifer materials for anaerobic microcosm studies in which phylogenetic probe analysis was complemented by microbial activity assays. Domain probe analysis of the aquifer samples showed that the communities were predominantly Bacteria; Eucarya and Archaea were not detectable. At the phylum and subclass levels, the FC and NC aquifer material had similar relative abundance distributions of 43 to 65% beta- and gamma-Proteobacteria (B+G), 31 to 35% alpha-Proteobacteria (ALF), 15 to 18% sulfate-reducing bacteria, and 5 to 10% high G+C gram positive bacteria. Compared to that of the NC region, the community structure of the FC material differed mainly in an increased abundance of B+G relative to that of ALF. The microcosm communities were like those of the field samples in that they were predominantly Bacteria (83 to 101%) and lacked detectable Archaea but differed in that a small fraction (2 to 8%) of Eucarya was detected regardless of the treatment applied. The latter result was hypothesized to reflect enrichment of anaerobic protozoa. Addition of nitrate and/or toluene stimulated microbial activity in the microcosms, but only supplementation of toluene alone significantly altered community structures. For the NC material, the dominant subclass shifted from B+G to ALF, while in the FC microcosms 55 to 65% of the Bacteria community was no longer identifiable by the phylum or subclass probes used. The latter result suggested that toluene exposure fostered the proliferation of phylotype(s) that were otherwise minor constituents of the FC aquifer community. These studies demonstrated that alterations in aquifer microbial communities resulting from specific anthropogenic perturbances can be inferred from microcosm studies integrating chemical and phylogenetic probe analysis and in the case of hydrocarbon contamination may facilitate the identification of organisms important for in situ biodegradation processes. Further work integrating and coordinating microcosm and field experiments is needed to explore how differences in scale, substrate complexity, and other hydrogeological conditions may affect patterns observed in these systems.  (+info)

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 ...
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 ...
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 ...
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 ...
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 ...
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
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,
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
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 ...
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 ...
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 ...
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-filling; 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 (
Deep-sea sediments cover ~70% of Earths surface and represent the largest interface between the biological and geological cycles of carbon. Diatoms and zooplankton faecal pellets naturally transport organic material from the upper ocean down to the deep seabed, but how these qualitatively different substrates affect the fate of carbon in this permanently cold environment remains unknown. We added equal quantities of 13C-labelled diatoms and faecal pellets to a cold water (−0.7 °C) sediment community retrieved from 1080 m in the Faroe-Shetland Channel, Northeast Atlantic, and quantified carbon mineralization and uptake by the resident bacteria and macrofauna over a 6-day period. High-quality, diatom-derived carbon was mineralized ,300% faster than that from low-quality faecal pellets, demonstrating that qualitative differences in organic matter drive major changes in the residence time of carbon at the deep seabed. Benthic bacteria dominated biological carbon processing in our experiments, ...
This article is a summary of chapter 5 of the [[Manual Sediment Transport Measurements in Rivers, Estuaries and Coastal Seas]],ref>Rijn, L. C. van (1986). Manual sediment transport measurements. Delft, The Netherlands: Delft Hydraulics Laboratory,/ref>. This article describes different measurement instruments available to measure sediment transport in rivers, coastal seas and estuaries. Many of these instruments are also described in separate articles (see text for links to these articles). ==Introduction== Various instruments for measuring the sediment transport rate are described. Usually the sediment transport is represented as the summation of the [[bed load]] and [[suspended load]] transport. To measure the [[bed load]] transport, two measuring methods are available: simple mechanical trap-type samplers (collecting the sediment particles transported close to the bed) and the recording of the bed profile as a function of time ([[bed form tracking]]). To measure the [[suspended load]] ...
Read "Assessment of the sediment quality of freshwater ecosystems in eastern China based on spatial and temporal variation of nutrients, Environmental Science and Pollution Research" on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
Being a major cause of eutrophication and subsequent loss of water quality, the turnover of phosphorus (P) in lake sediments is in need of deeper understanding. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. This P is incorporated in a poorly described mixture of autochthonous and allochthonous sediment and forms the primary storage of P available for recycling to the water column, thus regulating lake trophic status. To identify and quantify biogenic sediment P and assess its lability, we analyzed sediment cores from Lake Erken, Sweden, using traditional P fractionation, and in parallel, NaOH extracts were analyzed using 31P NMR. The surface sediments contain orthophosphates (ortho-P) and pyrophosphates (pyro-P), as well as phosphate mono- and diesters. The first group of compounds to disappear with increased sediment depth is pyrophosphate, followed by a steady decline of the different ester compounds. Estimated half-life times of these ...
Comparative Study on Microphytobenthic Pigments and Total Microbial Biomass by ATP in Intertidal Sediments - microphytobenthos;pigment;Adenosine-5 triphosphate (ATP);intertidal sediments;
The majority of a streams sediment load is carried in solution (dissolved load) or in suspension. The remainder is called the bed load.
A Gram-positive, rod-shaped, endospore-forming organism, strain BL3-6(T), was isolated from tidal flat sediments of the Yellow Sea in the region of Tae-An. A 16S rRNA gene sequence analysis demonstrated that this isolate belongs to the Bacillus cereu
The Haihe River Basin, which is one of the most water-scarce and polluted river basins in China, has abnormally high nitrogen levels. In this study, total hydrolyzable amino acids (THAAs) were measured in surface sediment and sediment core samples in the Haihe River Basin to determine if amino acids were potential sources of ammonium, organic nitrogen, and organic carbon. The rivers were found to be in a state of hypoxia and contain abnormally high levels of ammonium and organic nitrogen. Additionally, NH3-N was the predominant form of inorganic nitrogen in the surface sediments, while organic nitrogen accounted for 92.53% of sedimentary nitrogen. THAAs-C accounted for 14.92% of the total organic carbon, while THAAs-N accounted for more than 49.59% of organic nitrogen and 45.68% of total nitrogen. The major fraction of THAAs were protein amino acids. Three sediment cores of the most heavily polluted rivers also showed high levels of THAAs. Evaluation of the degradation index (DI) of sedimentary organic
D7363 - 13a Standard Test Method for Determination of Parent and Alkyl Polycyclic Aromatics in Sediment Pore Water Using Solid-Phase Microextraction and Gas Chromatography/Mass Spectrometry in Selected Ion Monitoring Mode ,
...An analysis of sediment cores indicates that biological and chemical c...While environmental changes at the lake over the past millennia have b... The past few decades have been unique in the past 200000 years in te...The study was published Oct. 19 in the Proceedings of the National ...,Arctic,lake,sediments,show,warming,,unique,ecological,changes,in,recent,decades,biological,biology news articles,biology news today,latest biology news,current biology news,biology newsletters
Two mud volcanoes in the Gulf of Mexico were examined to understand barium cycling in shallow seafloor sediment at regions of intense methane expulsion. Due to anaerobic oxidation of methane and sulfate reduction, barium interacts with methane and sulfate, producing barite fronts at the sulfate-methane transition and barium-rich pore fluids underneath. Formation waters likely feed volcanoes and deliver large amounts of Ba2+ to the system from below. Locally elevated Ba2+ concentrations amplified cycling, producing sigmodial pore water profiles in the shallowest sediment. The expulsion of Ba-rich fluids directly to the water column concentrates barite in surficial sediments, which can also enhance cycling. Further, two types of barium-rich, carbonate nodules were recovered. Rocky nodules resemble buried carbonate crusts, diagenetically altered by pore fluids. Smooth nodules are likely preserved barite fronts marking past sulfate-methane transitions. Both types of nodules can serve as a modern ...
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The USGS Woods Hole Science Center has been an active member of the Woods Hole research community for over 35 years. In that time there have been many sediment collection projects conducted by USGS scientists and technicians for the research and study of seabed environments and processes. These samples are collected at sea or near shore and then brought back to the Woods Hole Science Center (WHSC) for study. While at the Center, samples are stored in ambient temperature, cold or freezing conditions, depending on the best mode of preparation for the study being conducted or the duration of storage planned for the samples. Recently, storage methods and available storage space have become a major concern at the WHSC. The shapefile sed_archive.shp, gives a geographical view of the samples in the WHSCs collections, and where they were collected along with images and hyperlinks to useful resources ...
By inducing artificial turbidity currents to transport the sediments of obstructing bars into deeper water, the natural phenomenon of sediment transport by turbidity currents may be applied to the dredging of navigable channels. The method may be used provided that sufficient slope is present to allow removal of the sediment by currents, that the sediments are of a type which can form turbidity flows, and that equipment is available for mixing the sediment and water. No accurate cost analysis is presently available. ...
Biodegradation of hydrocarbons is a complex process, and a vast amount of hydrocarbon-degradation capacity remains to be exploited in the bioremediation of extensive areas of contaminated land throughout Europe and the world. DECAPAGE proposes to explore the microbial diversity of coastal microbial communities for hydrocarbon compounds degradation. Emphasis will be largely on hydrocarbon degrading microbial consortia adapted to oxic/anoxic oscillations with a special focus on anoxic metabolisms. This proposal has the ambition to characterize the chemical and microbiological aspects involved on hydrocarbons biodegradation. It is based on innovative concepts and the use of the latest technologies. Their combination will allow the description of the dynamic adaptation of bacterial communities to the presence of petroleum and how the oxygenation and redox oscillations affect their functioning. The DECAPAGE proposal seeks to provide : (1) novel analytical approaches for the identification of hydroxylated
INTRODUCTION. The marine sediments are an environmental matrix (Elderfield, 1978) in which the stratigraphic disposition conforms a record of the processes and balances that occur in the surface layers (Stumm & Morgan, 1981; Colombo et al, 1996). The chemical composition of the sediment depends on the mineralogical constitution of the mother rocks that originate it; the grain size, composition, and chemical characteristics of the environment in which it is deposited; the advective processes of the site; and anthropogenic contributions (Ahumada, 1998).. If the fraction of the natural or anthropogenic material that is input into an aquatic system is trapped in the sediments - and depending on its chemical quality - it can alter and/or change the substrate composition and may leave a record of such activity in the sediment column. In order for such a change to be recorded, it must be of a certain magnitude, persist over time, and occur in the absence of physical or biological disturbances ...
Maslin, Mark A.; Swann, George E.A. (2006). "Isotopes in marine sediments". In Leng, Melanie J. Isotopes in Palaeoenvironmental ... Rasskazov, Sergei V.; Brandt, Sergei Borisovich; Brandt, Ivan S. (2009). Radiogenic Isotopes in Geologic Processes. Dordrecht: ...
1] "Geologic Map Legends". Coastal Plain Rocks and Sediments. Maryland Geological Survey. Archived from the original on 26 May ...
The geologic time scale was developed during the 19th century, based on the evidence of biologic stratigraphy and faunal ... This may be the result of a halt in the deposition of sediment. Alternatively, the gap may be due to removal by erosion, in ... The continuous nature of the sampling means that it is also a powerful technique for the estimation of sediment-accumulation ... thickness of sediment layers (varves) and fossil diversity with time, related to seasonal or longer term changes in ...
"A Brief Summary of the Geologic History of Ohio", page 1. Madin; "3. Early Sediments: Oregon's first coast". Murray (1974); " ... This was a major boon to his reputation as his research was foundational to understanding that interval of American geologic ... "A Brief Summary of the Geologic History of Ohio". GeoFacts. Number 23. Ohio Department of Natural Resources, Division of ... ISBN 0-691-11345-9. Madin, Ian P. "Oregon: A Geologic History." Interpretive Map Series 28. Oregon Department of Geology and ...
"A Brief Summary of the Geologic History of Ohio", page 1. Madin; "3. Early Sediments: Oregon's first coast". Murray (1974); " ... Braden, Angela K. The Arkansas Dinosaur "Arkansaurus fridayi". Arkansas Geologic Survey. 2007. "A Brief Summary of the Geologic ... The geologic turmoil on the west coast was maintained as the Pacific Plate continued to slide under the North American Plate. ... Powerful geologic forces began to fold and distort the rocks of Idaho, Utah, and Wyoming, beginning the processes that would ...
Cretaceous Period sediments overlap the Paleozoic units in extreme southern Illinois. A bedrock geologic map was published by ... "Paleogeography and Geologic Evolution of North America". Global Plate Tectonics and Paleogeography. Northern Arizona University ... McDowell, R.C., (ed.), 2001, The geology of Kentucky -- A text to accompany the geologic map of Kentucky: USGS Professional ...
... and to more control on depositional mechanisms of sediments and the acting of sedimentary systems. Cyclic sediments ... "Cyclostratigraphy - from orbital cycles to geologic time scale". 2008. http://www.cprm.gov.br/33IGC/1312131.html Hinnov L.A. & ...
The sediments of the formation reflect a marine near-shore depositional environment. Cardozo, M. (1990). "The Copara ... Metallotect in Central Peru: Geologic Evolution and Ore Formation". In Fontboté, L.; Amstutz, G.C.; Cardozo, M.; Cedillo, E.; ...
The Escarpment Grit is a Triassic geologic formation. It is also referred to as the Nyoka Grit. The formation is composed of ... d'Engelbronner, E.R. (1996). "New palynological data from Karoo sediments, Mana Pools basin, northern Zimbabwe". Journal of ... fluvial sediments, mainly gritstones and coarse sandstones. Uranium is present in the Escarpment Grit of southern Zambia. The ...
Sediments from the surrounding mountains filled the valley over geologic time periods. After lakes within the valley receded, ... Large amounts of sediment from the volcanic San Juan Mountains continued to wash down into these lakes, along with some sand ... Sediments from both mountain ranges filled the deep chasm of the valley, along with huge amounts of water from melting glaciers ... and in buried deposits indicates that some of the sediment has been washed down in torrential flash floods. In 2002, geologists ...
... looks at geologic sediments and rocks, for signs of ancient earthquakes. It is used to supplement seismic ... Paleoseismology is usually restricted to geologic regimes that have undergone continuous sediment creation for the last few ...
After millions of years, these sediments have been titled and uplifted. Weathering has removed more easily eroded material ... Structurally, the Marlboro Mountains constitute a geologic formation known as a dip slope. The sedimentary layers comprising ... The Marlboro Mountains are primarily formed of shallow marine/delta sediments deposited during the late Ordovician, ... form an imposing geologic barrier just west of the Hudson River. They subdivide the relatively flat Hudson River Valley (a ...
The result is a sequence of sediments that wedges out in one direction. This is usually the case on the margins of geologic ... When a tectonic phase occurred while sedimentation of new sediments continued, every new layer will have a slightly different ...
On the geologic map, "Trenton Gravel" is used to describe most of these sediments. However, much of the alluvial sediments that ... The sediments deposited in that sea are now located in the Great Valley section. (See below) The sediments placed from the ... ISBN 0-87842-227-7 The Pennsylvania Geologic Survey Physiographic Provinces and Sections of Pennsylvania The Geologic Story of ... The sediments that were deposited in a sea between an island-arc and the Iapetus eventually were squeezed and deformed along a ...
Lexicon of Canadian Geologic Units. "Belloy Formation". Archived from the original on 2012-07-08. Retrieved 2009-02-12. ... John Group). It is unconformably overlies Mississippian sediments such as those of the Rundle Group. The Belloy Formation is ...
... can be preserved in sediments. Sedimentology Sequence stratigraphy Tectonic-climatic interaction Sadler, Peter M. "Sediment ... "The stratigraphic filter and bias in measurement of geologic rates." Geophysical Research Letters 38.11 (2011): L11405. Schumer ... Conversely, it also explains that the maximum sediment accumulation rates seen in the Cambrian at the start of the Phanerozoic ... The Sadler effect describes variation in apparent sediment accumulation rates and bed thicknesses back through time inherent to ...
Sometimes the sediment would be mixed with huge chunks of ice, which would leave voids, or kettles, in the soil. These kettles ... Geologic Atlas of Ramsey County, Atlas C-7 (Map) (1992 ed.). Minnesota Geological Survey, University of Minnesota. § Plate 2. , ... S. S. Goldich (2), H. Baadsgaard (2 (1959). "Investigations in Radioactivity-Dating of Sediments". AAPG Bulletin. 43. doi: ...
Interbedded alluvial sediments are also found between many of the flows. In the eastern Snake River Plain, the Snake River lies ... It is not a single homogeneous geologic formation. Rather it consists of a volcanic pile of the Quaternary Snake River Group ...
Local sediments were being eroded away rather than deposited from the Carboniferous to the Permian, so there are no rocks of ... During the Triassic, New Jersey was experiencing geologic upheaval caused by the breakup of Pangaea. Rifts formed in the state ... Local reptiles would sometimes be preserved in the sediments of these lakes. During the Triassic, local dinosaurs left behind ... Geologic units of New Jersey FossilsofNJ.com Paleoportal: New Jersey. ...
Before the Rove sediments were laid down, during the Archean Eon, the Algoman orogeny added landmass along a border from South ... "Voyageurs National Park, Geologic History". National Park Service, Explore Geology: 1. Retrieved March 25, 2010. Davis, Peter ( ... After the Rove sediments were deposited, the Penokean orogeny added more land mass by accretion that occurred from the south. A ... The Rove Formation is the youngest of the many Animikie layers; it consists of gently tilted fine-grained sediments. It is ...
The park's geologic record preserves three different groups of rock and sediment. The oldest rocks are Early to Middle ... Geologic map of the Colorado National Monument and adjacent areas, Mesa County, Colorado: U.S. Geological Survey, Geologic ...
Illinois State Geological Survey - Glossary of Geologic Terms. References[edit]. *^ Essentials of Geology, 3rd Ed, Stephen ... These rocks can then in turn again be weathered and eroded to form a second generation of sediment. ... Diagenetic processes can transform these sediments into rock through cementation and lithification, forming sedimentary rocks ...
Other sediments may have been added but, if they ever existed, were completely removed by erosion. Such gaps in the geologic ... At the same time, sediment filled the lakes behind the dams. Sediment would fill a lake behind a 150-foot (46 m)-high dam in ... A geologic formation is a rock unit that has one or more sediment beds, and a member is a minor unit in a formation. Groups are ... Next in the geologic column is the 200-foot (60 m)-thick Toroweap Formation (see 6c in figure 1). It consists of red and yellow ...
Sediment from the Valais ocean crop out in the Versoyen unit. The basement of the Briançonnais microcontinent crop out at Gran ... The geographic region of the Massif Central coincides with the geologic region with the same name. It is part of the Variscan ... Sediments from the Piemont-Liguria Ocean crop out in Embrunais and Ubaye. The Jura mountains are part of the Helvetic nappes, ...
If the basin forms slowly, as in the northern Appalachians, it fills with shallow-water sediments. If it forms rapidly, as in ... The name flysch was introduced in geologic literature by the Swiss geologist Bernhard Studer in 1827. Studer used the term for ... The insight that flysch is actually a deep marine sediment typical for a particular plate tectonic setting came only much later ... Flysch consists of repeated sedimentary cycles with upwards fining of the sediments. At the bottom of each cycle are sometimes ...
Of the modern geologic features, only the land bridge between South America and North America was absent, although South ... with long term burial of carbon in sediments, produced a carbon and water vapor sink. This, combined with higher surface albedo ...
Geologic cross section of Kittatinny Mountain. This cross section shows metamorphic rocks, overlain by younger sediments ... Main articles: History of Earth and Geologic time scale. The geologic time scale encompasses the history of the Earth.[10] It ... "Surficial Geologic Maps" in New Hampshire Geological Survey, Geologic maps. des.nh.gov ... Geologic materials[edit]. The majority of geological data comes from research on solid Earth materials. These typically fall ...
Sediment dispersal and accumulation on continental margins are evaluated to understand how strata are formed in these ... paleohurricane studies in Florida that attempt to understand how tropical cyclone deposits are preserved into the geologic ... Jon Martin also studies the discharge of water from deep-sea sediments that accumulate along active margins. His work attempts ... Ellen Martinhelped develop and applies Sr isotopes as a chemostratigraphic tool to date and correlate marine sediments. She ...
Finally, we examine geologic time, structural geology, geologic maps, and plate tectonics. Connections are drawn whenever ... Sedimentology is the study of the erosion, transport, and deposition of sediment in rivers, deltas, beaches, and many other ... To ensure that you have the proper background to assess the geologic literature, students must have taken at least one of the ... It continues with a strong focus on the many forces and geologic events that have shaped North America. Finally, major episodes ...
Ferric Compounds, Ferrous Compounds, Geologic Sediments, Nitrates, Oxidation-Reduction, Proteobacteria, Soil Pollutants, ... Multiple influences of nitrate on uranium solubility during bioremediation of uranium-contaminated subsurface sediments.. Title ... When nitrate was added to sediments in which U(VI) had been reduced, U(VI) reappeared in solution. Parallel studies with the ... Nitrate inhibited U(VI) reduction in acetate-amended aquifer sediments collected from a uranium-contaminated site in New Mexico ...
Van Dyke, Gilbert Rusk (1940) Geologic report of Black Butte, Antelope Valley, California. Geologic report of Puente Hills, ... Holloway, John Marshall (1940) Areal geology and contact relations of the basement complex and later sediments, west end of the ... Shoemaker, Eugene Merle and Glover, Patrick Norman and Muehlberger, William R. and Nicolai, Fred H. (1947) A Geologic Report on ... George, John (Jack) Wesley (1937) Geologic report on a portion of the Little Tujunga quadrangle and a portion of the Sunland ...
Bill Breed and George Billingsley published a popular geologic map of the Grand Canyon. ... and asked to see the sites where Merle had found fossils in the Tropic Shale sediments, laid down in the Cretaceous Western ...
Theme_Keyword: sediment data. Theme_Keyword: marine sediment data. Theme_Keyword: legacy data. Theme_Keyword: geologic data. ... Theme_Keyword: offshore sediments. Theme_Keyword: coastal sediments. Theme_Keyword: beach sediments. Theme_Keyword: estuary. ... Enumerated_Domain_Value: SEDIMENT DRILL. Enumerated_Domain: Enumerated_Domain_Value: SEDIMENT TRAP. Enumerated_Domain: ... Theme_Keyword: sediment samples. Theme_Keyword: USGS. Theme_Keyword: Coastal and Marine Geology Program. Theme_Keyword: GIS. ...
Geologic principles and processes. Stratigraphic principles. *Principle of original horizontality. *Law of superposition ... In this equation ws is the sediment settling velocity, g is acceleration due to gravity, and D is mean sediment diameter. ν. {\ ... "Lecture 21-Suspended Sediment Transport" (PDF). Lecture Notes: Fluvial Sediment Transport. Kent State. Retrieved 25 December ... Sediment moved by water can be larger than sediment moved by air because water has both a higher density and viscosity. In ...
Miami: Miami Geologic Society.Google Scholar. *. Gilman, E., J. Ellison, and R. Coleman. 2007. Assessment of mangrove response ... Hurricane Wilma Sediment deposition Mangroves Accretion Nutrient biogeochemistry Florida Everglades This is a preview of ... Hurricane signals in salt marsh sediments: Inorganic sources and soil volume. Limnology and Oceanography 52: 1231-1238.CrossRef ... Sediment accretion in coastal wetlands: A review and simulation model of processes. Current Topics in Wetland Biogeochemistry 2 ...
Effects of proposed sediment borrow pits on nearshore wave climate and longshore sediment transport rate along Breton Island, ... Geologic Evolution of Cat Island, Mississippi The geologic evolution of Cat Island has been influenced by deltaic, lagoonal/ ... Geologic Evolution of Cat Island, Mississippi. The geologic evolution of Cat Island has been influenced by deltaic, lagoonal/ ... and geologic (decades to millennia) evolution of coastal systems. Investigations utilize a combination of geophysics, sediment ...
Walker Lane geologic trough - E. California, W. Nevada. May 22, 2019. Mysterious Ringing of the Earth. May 22, 2019 ... the metal contained in the sediments can move from the particulate phase (associated with the sediment) to the soluble part (to ... "The highly polluted sediments of the Ego stream reflect how far away it is from the optimum quality conditions that should be ... Although sediments act as a drain for pollutants, they can also act as a source of pollutants under certain environmental ...
Lawrence are as high as has been observed in the worlds most contaminated marine sediments. ... Walker Lane geologic trough - E. California, W. Nevada. May 22, 2019. Mysterious Ringing of the Earth. May 22, 2019 ... Lawrence River sediments. by Canadian Science Publishing (NRC Research Press) Credit: Canadian Science Publishing (NRC Research ... Lawrence River sediments". Canadian Journal of Fisheries and Aquatic Sciences. www.nrcresearchpress.com/doi/a … 1139/cjfas-2014 ...
Geologic Sediments / chemistry* * Hydrogen-Ion Concentration * Phosphates / analysis * Phosphates / chemistry* * Silicon ... Enhanced attenuation of septic system phosphate in noncalcareous sediments Ground Water. Jan-Feb 2003;41(1):48-56. doi: 10.1111 ...
Sampling Bed Sediments. Photographs or techniques and equipment used to sample bed sediments (17K JPEG) 21. Sources and Sinks ... 4. Geologic Settings. Maps and Vignettes of the Mississippi River showing different geologic settings (132K JPEG) 5.Water ... PCBs in Bed Sediments. Graphs showing the concentrations of polychlorinate biphenyls (PCBs) in bed sediments stored in the ... Lead in River Waters and Sediments. Map and pie diagrams showing distributions of lead in waters and suspended sediments of the ...
... sediments; the deposition, erosion, and distribution of marine sediments; geologic and oceanographic processes controlling ... paleoenvironmental controls on fossil groups and sediment types; and interactions of continental and oceanic geologic processes ... The Marine Geosciences Section supports research on processes that occur on and below the sea floor and at the water/sediment/ ... The drilling process involves collecting and logging geologic samples from the floor of deep ocean basins through rotary coring ...
... that also present abundant geologic hazards. ... The high sediment load in the creek has required that the ... the distribution of bedload sediment across the alluvial fan. *the flux of suspended sediment down Swift Creek (sampling, ... The US Environmental Protection Agency has determined that there is sufficient asbestos in the Swift Creek sediments to pose a ... In addition, hydrologic modeling will predict the discharge and sediment flux from the watershed under different climate ...
Deep-sea sediments lead to new understanding of solar system. Results from deep-ocean sediments advance dating in geologic ... A "calendar" of the past has revolutionized the dating of geologic archives, identifying ages of geologic periods based on ... The team used geologic records from deep-sea drilling cores recovered using the NSF-funded research drillship JOIDES Resolution ... On geologic time scales (thousands to millions of years), variations in Earths orbit are the pacemakers of the ice ages. ...
Wabasha County Geologic Atlas Part B. SDOVBDPY metadata. Sediments Overlying Bedrock. Minnesota DNR Waters County Geologic ... County Geologic Atlas and Regional Hydrogeologic Assessment Program, Wabasha County Geologic Atlas, Part B, County Geologic ... Wabasha County Geologic Atlas, Part A, County Geologic Atlas Series C-14, published by the Minnesota Geological Survey, 2001. ... Overlying sediment type: alluvium; outwash or colluvium; shallow bedrock (refers to areas with little or no sediment ...
Geologic Ages. PRESENT DAY TEMPERATURES. Thermal regimes. Present day temperatures. Drilling-induced complications. Geologic ... Recent sediments. Petroleum generation. Biogenic gas. Petroleum migration. Maturation and alteration of petroleum in reservoirs ... Sediment accumulation rates. Compaction. Unconformities. Rotation of beds (including folding). Faulting. Intrusions and diapirs ... Geologic setting. Direct measurement. Calculation from thermal conductivity and heat flow. Paleosurface temperatures. ...
Large amounts of methane are produced in marine sediments but are then consumed before contacting aerobic waters or the ... Geologic Sediments * Lipid Metabolism * Methane / metabolism* * Phylogeny * RNA, Ribosomal, 16S / analysis * Water Microbiology ... Methane-consuming archaebacteria in marine sediments Nature. 1999 Apr 29;398(6730):802-5. doi: 10.1038/19751. ... Large amounts of methane are produced in marine sediments but are then consumed before contacting aerobic waters or the ...
Geologic Sediments • Geology • Haplorhini • Locomotion • Mammals • Paleontology • Phylogeny • Platyrrhini • Primates • ... Andean uplift also generates the sediment fill, nutrient supply, river routing, and soil composition of the adjacent lowland ... But the interactions are bi-directional, because changes in climate, hydrology, and sediment supply influence rates of uplift ... 2. To establish a more precise geologic chronology for the mammalian faunas between the Late Eocene and Middle Miocene (between ...
A Geologic-Engineering Analysis, Part I, Volume 30 - 1st Edition. Print Book & E-Book. ISBN 9780444888495, 9780080868882 ... Porosity characteristics of carbonate sediments and rocks. Formation of secondary matrix porosity in limestones. Porosity in ... Carbonate Reservoir Characterization: A Geologic-Engineering Analysis, Part I, Volume 30 1st Edition. 0.0 star rating Write a ... 6. Pore Geometry of Carbonate Rocks and Capillary Pressure Curves (Basic Geologic Concepts) (R.L. Jodry). Classification of ...
Sediment: Influence on Aquatic Life / Suzanne M Gray Sedimentation Control and Erosion: Engineering Techniques / Jose Miguel ... Geologic Carbon Capture and Storage / Sean I Plasynski, John T Litynski, Timothy R Carr, ... Carbon Sequestration: Sediments / Eswaran Padmanabhan Carbon Sequestration: Semiarid Regions of India / Cherukumalli Srinivasa ...
Fine Sediment ,ul,,li,Young geologic system ,/li,,/ul,,ul,,li,~75% of fine sediment load is natural ,/li,,/ul,,ul,,ul,,li,Lower ... Slide 4: Fine Sediment Young geologic system 75% of fine sediment "natural background condition" Therefore, high phosphorus ... Sediment =  phosphorus load ,/li,,/ul,Huckleberry Creek after January 1990 flood ... salt marsh emergent vegetation Sediment surface bacteria on mudflats De-nitrification ...
  • The majority of research in geology is associated with the study of rock, as rock provides the primary record of the majority of the geologic history of the Earth. (wikipedia.org)
  • Nitrate inhibited U(VI) reduction in acetate-amended aquifer sediments collected from a uranium-contaminated site in New Mexico. (umass.edu)
  • Cores and sediment samples may be examined without constraint. (usgs.gov)
  • The bathymetry, sidescan sonar, and sediment cores provide information about the extent and texture of the seafloor features. (usgs.gov)
  • The team used geologic records from deep-sea drilling cores recovered using the NSF-funded research drillship JOIDES Resolution to extend the astronomical time scale by about eight million years. (nsf.gov)
  • They cruised small canals and arms of the river to take sediment cores from old beach ridges, and they used sonar to chart the shape of the seafloor near the mouth. (whoi.edu)
  • Not only that but we have evidence from geologic records, ice cores, and sediment cores from ocean cores. (universetoday.com)
  • The primary sources of data are 'geohistorical': the fossils, geochemistry and sediments of the geologic record. (nsf.gov)
  • This vertical display of the various geologic eras, periods, and epochs supposedly illustrates the nature of the fossil record, with recent fossils on the top and older ones on the bottom. (icr.org)
  • At the start of the Flood all the fountains of the great deep were rent open sending repeated pulses of water toward the continents from every direction bringing sediments and marine fossils to the land. (icr.org)
  • There are fossils in the metamorphosed sediments of a type of blue-green algae called stromatolites. (idaho.gov)
  • Geologic units from the same time but different parts of the world often look different and contain different fossils, so the same time-span was historically given different names in different locales. (wikipedia.org)
  • This immobility makes it highly unlikely that these porphyrins could have moved from younger formations into the Nonesuch sediments, and the widely disseminated particulate organic matters and fossils in this Precambrian shale are certainly indigenous. (sciencemag.org)
  • Changes in these parameters can be identified in rock or sediment archives, like fingerprints left behind. (nsf.gov)
  • Although sediments act as a drain for pollutants, they can also act as a source of pollutants under certain environmental conditions (like changes in the composition of the water or movement of the sediments owing to a flood event). (phys.org)
  • Quantity, composition, and source of sediment collected in sediment traps along the fringing coral reef off Molokai, Hawaii. (biomedsearch.com)
  • Based on quantity and composition of trapped sediment, floods recharged the reef flat with land-derived sediment, but had a low potential for burying coral on the fore reef when accompanied by high waves. (biomedsearch.com)
  • Study of geologic records of dust composition, sources and deposition rates is important for understanding the role of dust in the overall planetary radiation balance, fertilization of organisms in the world's oceans, nutrient additions to the terrestrial biosphere and soils, and for paleoclimatic reconstructions. (unl.edu)
  • Third, aeolian sediment particle size and composition can be determined so that dust source areas can be ascertained and dust transport pathways can be reconstructed. (unl.edu)
  • The sources, abundances, and quality (i.e., labile or recalcitrant) of the organic matter and the composition of the microbial assemblages vary between sediments. (nih.gov)
  • The use of the metagenomics, where bulk samples of sediment are sequences without separation, allows recognition of unknown organism and determination of the composition of the ecosystem. (dailygalaxy.com)
  • This GIS data layer represents point coverage of seafloor sediment size and composition in Massachusetts territorial waters. (noaa.gov)
  • 2010. Seafloor sediment composition in Massachusetts determined using point data. (noaa.gov)
  • Here, we examine new and previously published sediment metagenomes from the Baltic Sea and the nearby Kattegat region to determine connections between geochemistry and the community potential to degrade organic carbon. (nih.gov)
  • We examined microbial communities in Baltic Sea sediments, which were deposited across various climatic and geographical regimes to determine the relationship between microbial potential for breakdown of organic matter and abiotic factors, including geochemistry and sediment lithology. (nih.gov)
  • that also present abundant geologic hazards. (carleton.edu)
  • Debris flows and sediment-laden floods in the Transverse Ranges of southern California pose severe hazards to nearby communities and infrastructure. (usgs.gov)
  • It's public, but whether it gets disseminated to the people who make land-use decisions and planning for geologic hazards doesn't necessarily happen," said Dan McShane, a geologist in Whatcom County, Wash. (pbs.org)
  • This sediment is important to the soil budget and ecology of several islands. (wikipedia.org)
  • Total P inputs from storm-derived sediments were equivalent to twice the average surface soil nutrient P density (0.19 mg cm −3 ). (springer.com)
  • Allochthonous mineral inputs from Hurricane Wilma represent a significant source of sediment to soil vertical accretion rates and nutrient resources in mangroves of southwestern Everglades. (springer.com)
  • The measured volumes of sediment, watershed morphology, distributions of burn severity within each watershed, the time since the most recent fire, triggering storm rainfall conditions, and engineering soil properties were analyzed using multiple linear regressions to develop two models. (usgs.gov)
  • Grains begin to move and sediment is entrained by the wind when fluid forces (lift, drag, moment) exceed the effects of the weight of the particle, and any cohesion between adjacent particles as a result of moisture, salts, or soil crusts. (nps.gov)
  • In addition, hydrologic modeling will predict the discharge and sediment flux from the watershed under different climate conditions. (carleton.edu)
  • This river is characterized by a flash flood regime discharging large amounts of water (more than 20 times the mean water discharge) and sediment in very short periods lasting from hours to few days. (usgs.gov)
  • The Hydraulics Characteristics section presents a survey of the hydraulic characteristics of the river, examining a number of variables that affect water discharge and sediment load. (ku.edu)
  • A combination of geophysics, sediment sampling, and chronology techniques are used to characterize the regional geomorphologic response of coastal systems to environmental changes. (usgs.gov)
  • This astronomical answer has a built-in clock (computing planetary orbits backward in time), providing an accurate chronology for the geologic record. (nsf.gov)
  • The UPV/EHU's Hydrology and Environment Research Group has located the stretches in the River Deba and its tributaries posing the greatest potential hazard owing to their high metal content, has identified the sources of pollution and has assessed the effect that a certain type of flood event has on the carrying away and distribution of sediments and associated metals. (phys.org)
  • The UPV/EHU's Hydrology-Environment Group has conducted research on the River Deba and its tributaries to assess the influence of anthropogenic inputs and the effect exerted by major flooding events on the distribution of the metals associated with the sediments. (phys.org)
  • The topics in shallow surface geophysics include field geophysical surveys of glaciotectonic deformation of Long Island sediments using ground penetrating radar, electrical resistivity, seismic reflection and refraction as well as borehole geophysics. (stonybrook.edu)
  • Aeolian or eolian (depending on the parsing of æ ) is the term for sediment transport by wind . (wikipedia.org)
  • Bedforms are generated by aeolian sediment transport in the terrestrial near-surface environment. (wikipedia.org)
  • Aeolian sediment transport is common on beaches and in the arid regions of the world, because it is in these environments that vegetation does not prevent the presence and motion of fields of sand. (wikipedia.org)
  • A perspective model of the morphology and geologic framework near Petit Bois Island showing the relationships between seafloor features and the subsurface. (usgs.gov)
  • Prior to developing the models, 32 volumes of sediment, and related parameters for watershed morphology, burn severity and rainfall conditions were retained to independently validate the long-term model. (usgs.gov)
  • Understanding how and why coasts have changed in the past can provide insight into modern coastal behavior, future coastal evolution, the extent and quality of sediment resources, and spatial variability in the resilience of coastal ecosystems, all of which inform coastal resource management. (usgs.gov)
  • A geologic province is a spatial entity with common geologic attributes. (mcgill.ca)
  • The selected papers in Geologic Modeling and Mapping comprise a broad range of powerful techniques used nowadays in the earth sciences. (springer.com)
  • Based on simulations, large volumes of sediment eroded from the hillslopes were redeposited within the channel network throughout the storm, leading to the initiation of numerous debris flows as a result of the mass failure of sediment dams that built up within the channel. (usgs.gov)
  • Debris-retention basins protect communities and infrastructure from the impacts of debris flows and sediment-laden floods and also provide critical data for volumes of sediment deposited at watershed outlets. (usgs.gov)
  • In this study, we supplement existing data for the volumes of sediment deposited at watershed outlets with newly acquired data to develop new empirical models for predicting volumes of sediment produced by watersheds located in the Transverse Ranges of southern California. (usgs.gov)
  • A "long-term model" was developed for predicting volumes of sediment deposited by both debris flows and floods at various times since the most recent fire from a database of volumes of sediment deposited by a combination of debris flows and sediment-laden floods with no time limit since the most recent fire (n = 344). (usgs.gov)
  • A subset of this database was used to develop an "emergency assessment model" for predicting volumes of sediment deposited by debris flows within two years of a fire (n = 92). (usgs.gov)
  • Ten of these volumes of sediment were deposited by debris flows within two years of a fire and were used to validate the emergency assessment model. (usgs.gov)
  • The models were validated by comparing predicted and measured volumes of sediment. (usgs.gov)
  • These validations were also performed for previously developed models and identify that the models developed here best predict volumes of sediment for burned watersheds in comparison to previously developed models. (usgs.gov)
  • The sediment volume data represent a broad sample of conditions found in Ventura, Los Angeles and San Bernardino Counties, California. (usgs.gov)
  • These studies will allow engineers to design sediment retention structures of appropriate size and residence time. (carleton.edu)
  • Further application of the new method promises to reach farther back, one step and geologic record at a time. (nsf.gov)
  • The expression geologic time refers to the vast span from Earth 's beginnings to the present, about 4.6 billion years. (encyclopedia.com)
  • Instead of thinking in terms of years, centuries, or even millennia, the most basic unit is a million years, and even that is rather small when compared with the four eons into which geologic time is divided. (encyclopedia.com)
  • Geologic time is divided according to two scales. (encyclopedia.com)
  • The more well-known of these is the geologic scale, which divides time into named groupings according to six basic units: eon, era, period, epoch, age, and chron. (encyclopedia.com)
  • IMPORTANCE Sediments sequester organic matter over geologic time scales and impact global climate regulation. (nih.gov)
  • As one example shows, if all of geologic time were compressed into a single year, the first Homo sapiens would have appeared on the scene at about 8:00 p.m. on December 31. (encyclopedia.com)
  • In another example, geologic time is compared to the distance from Los Angeles to New York City. (encyclopedia.com)
  • Needless to say, the scope of geologic time compared with the units with which we are accustomed to measuring our lives (or even the history of our civilization) is more than a little intimidating. (encyclopedia.com)
  • The presenta- tions on the geologic record of eolian deposition documented our present understanding of the na~e and causes of climate change on time scales of the last glacial ages (tens of thousands of years) to time scales over which the arrangement of continents, mountains, and oceans has changed sub- stantially (tens of millions of years). (bookdepository.com)
  • It follows that placement of the surface in geologic time is only approximate, that is, partly pre-Tertiary, or late Cretaceous, and partly post-Cretaceous, or early Tertiary. (ku.edu)
  • Probably every textbook in use in America which in any way deals with evolutionary subjects includes a presentation of the 'Geologic Column,' or the 'Geologic Time Scale' as it is sometimes called. (icr.org)
  • The first known geologic event in this region took place 550 to 600 million years ago (Early of Middle Cambrian time). (fws.gov)
  • The next major geologic event took place in the Middle Cambrian time (500 to 550 million years ago). (fws.gov)
  • The geologic time scale ( GTS ) is a system of chronological dating that relates geological strata ( stratigraphy ) to time. (wikipedia.org)
  • The table of geologic time spans, presented here, agree with the nomenclature , dates and standard color codes set forth by the International Commission on Stratigraphy (ICS). (wikipedia.org)
  • The following four timelines show the geologic time scale. (wikipedia.org)
  • A "calendar" of the past has revolutionized the dating of geologic archives, identifying ages of geologic periods based on astronomy. (nsf.gov)
  • 1000 times higher than during non-storm periods, primarily because of sediment resuspension by waves. (biomedsearch.com)
  • Second, a number of dating methods can be applied to sediment archives, which allows identification of specific periods of greater or lesser dust flux. (unl.edu)
  • An outline of the theory of hydromechanics and rheological models for geologic deformation is included to place various analytical approaches in proper context and to provide an introduction to this broad topic for nonspecialists. (springer.com)
  • However, rigorous application of full coupling is often difficult because (1) the rheological behavior of geologic media is complex and poorly understood and (2) the architecture, mechanical properties and boundary conditions, and deformation history of most geologic systems are not well known. (springer.com)
  • This redistribution of the topography implies extensive deformation of soft, freshly deposited sediments. (icr.org)
  • More generally, results provide a quantitative framework for assessing the potential of runoff-generated debris flows based on sediment supply and hydrologic conditions. (usgs.gov)
  • Emphasis is on the structure of turbulent shear flows and the forces exerted by fluid motions on bed of loosed sediment. (nottingham.ac.uk)
  • The drilling process involves collecting and logging geologic samples from the floor of deep ocean basins through rotary coring and hydraulic piston coring. (nsf.gov)
  • Every effort has been made to ensure the interpretation shown conforms to sound geologic and cartographic principles. (mn.us)
  • Emphasis is placed on understanding geologic principles and methods as applied to environmental science, Earth resources, and public policy. (jhu.edu)
  • Sediment transport is the movement of solid particles ( sediment ), typically due to a combination of gravity acting on the sediment, and/or the movement of the fluid in which the sediment is entrained. (wikipedia.org)
  • Sediment transport due only to gravity can occur on sloping surfaces in general, including hillslopes , scarps , cliffs , and the continental shelf -continental slope boundary. (wikipedia.org)
  • Ripples and dunes form as a natural self-organizing response to sediment transport. (wikipedia.org)
  • Coastal sediment transport results in these evenly spaced ripples along the shore. (wikipedia.org)
  • Coastal sediment transport results in the formation of characteristic coastal landforms such as beaches , barrier islands , and capes. (wikipedia.org)
  • Another factor taken into consideration in this study was the mobilising of large quantities of sediments during the building of transport infrastructure, because it renders the effluent susceptible to being carried away by heavy rainfall. (phys.org)
  • The coupled ocean-atmosphere-wave-sediment transport (COAWST) model is used to hindcast Hurricane Ivan (2004), an extremely intense tropical cyclone (TC) translating through the Gulf of Mexico. (usgs.gov)
  • Transport of fine sediment by wind may cause dust storms, events in which visibility is reduced to less than 1 km by blowing dust. (nps.gov)
  • Modes of sediment transport by the wind (after Pyle, 1987). (nps.gov)
  • For any wind shear velocity, there is a potential rate of sand transport or transport capacity, which is only reached when the availability of sediment is unrestricted (e.g., most loose sand surfaces). (nps.gov)
  • This kinetic energy is used to perform all sorts of work: from the transport of sediments to turning electric generators in hydroelectric plants. (uoregon.edu)
  • The perfect multi-coloured spheres stood out from natural sediment, even though they were the size of sand grains," said the lead author of the study, Rowshyra Castañeda, a former McGill MSc student (now at University of Toronto). (phys.org)
  • The site was caked with a distinctive black sand unlike the sediments nearby-and Wu noted that the sediments must have washed into Lajia less than a year after the earthquake. (nationalgeographic.com)
  • With fluid dynamics as background, the course deals with sediment movement as bed load and suspended load, and with the geometry, kinematics, and dynamics of ripple and dune bed forms. (nottingham.ac.uk)