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Fine-grained sediments, or “fines,” are nearly ubiquitous in natural sediments, even in the predominantly coarse-grained sediments that host gas hydrates. Fines within these sandy sediments can be mobilized and subsequently clog flow pathways while methane is being extracted from gas hydrate as an energy resource. Using two-dimensional (2D) micromodels to test the conditions in which clogging occurs provides insights for choosing production operation parameters that optimize methane recovery in the field. During methane extraction, several processes can alter the mobility and clogging potential of fines: (1) fluid flow as the formation is depressurized to release methane from gas hydrate, (2) shifting pore-fluid...
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The 2008 - Present Ecosystem History of South Florida's Estuaries Database contains listings of all sites (modern and core) and modern monitoring site survey information (water chemistry, floral and faunal data, etc.). Three general types of data are contained within this database: 1) Modern Field Data (2008-present), 2) Master list of location information on all modern sites, and 3) Core data - location information. Data are available for modern sites (from 2008 to present) and cores in the general areas of Florida Bay, Biscayne Bay, and the southwest (Florida) coastal mangrove estuaries. Specific sites in the Florida Bay area include Taylor Creek, Bob Allen Key, Russell Bank, Pass Key, Whipray Basin, Rankin Bight,...
Categories: Data Release - Revised; Tags: 002, 004, 007, 008, 012, All tags...
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These data were collected from the TOPGUN-SODA10 2AK core collected in 2010 by LacCore (University of Minnesota), the USGS. and the University of California (U.C.) Berkeley. The 8.9 meter length core had stable isotopes of oxygen and carbon sampled every 10 millimeters or so, and diatoms samples at every 50 millimeters to 200 millimeters depending on the depth in the core. mineralogic data were collected using X-ray diffraction and grain-size analysis were done at various depths. These data are used to interpret the Holocene and late Pleistocene hydrology and paleoclimate of the lake and the region. The interpretation can be found in: Rosen, M.R., Reidy, L., Starratt, S., Zimmerman, S., in review, Middle Holocene...
We investigated the bioavailability via diet of spiked benzo[a]pyrene (BaP) and 2,2',5,5'-tetrachlorobiphenyl (PCB-52) from different carbonaceous (non-carbonate, carbon containing) particle types to clams (Macoma balthica) collected from San Francisco Bay. Our results reveal significant differences in absorption efficiency between compounds and among carbonaceous particle types. Absorption efficiency for PCB-52 was always greater than that for BaP bound to a given particle type. Among particles, absorption efficiency was highest from wood and diatoms and lowest from activated carbon. Large differences in absorption efficiency could not be simply explained by comparatively small differences in the particles' total...
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In 1991, the U.S. Geological Survey (USGS) began a study of more than 50 major river basins across the Nation as part of the National Water-Quality Assessment (NAWQA) project of the National Water-Quality Program. One of the major goals of the NAWQA project is to determine how water-quality and ecological conditions change over time. To support that goal, long-term consistent and comparable ecological monitoring has been conducted on streams and rivers throughout the Nation. Fish, invertebrate, and algae data collected as part of the NAWQA program were retrieved from the USGS Aquatic Bioassessment database for use in trend analysis. Ultimately, these data will provide insight into how natural features and human...
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One of the primary goals of South Korea’s second Ulleung Basin Gas Hydrate Expedition (UBGH2) was to examine the geotechnical properties of the marine sediment associated with methane gas hydrate occurrences found offshore of eastern Korea in the Ulleung Basin, East Sea. Methane gas hydrate is a naturally occurring crystalline solid that sequesters methane in individual molecular cages formed by a lattice of water molecules. During UBGH2, concentrated gas hydrate was found in two sedimentary environments: gas hydrate was found in thin, coarse-grained sediment layers interbedded with fine-grained sediment (fines, such as clays and muds) and as veins of essentially pure gas hydrate within predominantly fine-grained...
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The urbanized area of downtown Menlo Park is subject to persistent flooding and sediment deposition by San Francisquito Creek in South San Francisco Bay. To mitigate these events, a suite of cores was collected in 2002 at the mouth of the creek to determine sediment depositional rates on the delta. One of those cores (721-1) was selected for microbiological (pollen, diatoms, and foraminifera) and geochemical analyses to reconstruct a depositional record over the past two millennia. This data release provides radiocarbon dates, census counts of benthic foraminifera, diatoms, and palynomorphs, and the measurement of anthropogenic metals and other elements in sediments from this core.
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The safety, effectiveness and longevity of many construction and geotechnical engineering projects rely on correctly accounting for the evolution of soil properties over time. Critical sediment properties, such as compressibility, can change in response to pore-fluid chemistry changes, particularly if the sediment contains appreciable concentrations of fine-grained materials. Pore-fluid changes act at the micro scale, altering interactions between sediment particles, or between sediment particles and the pore fluid. These micro-scale alterations change how sediment fabrics and void ratios develop, which directly impacts macro-scale properties such as sediment compressibility. The goal of this study is to correlate...
We tested the recolonization of the phytobenthic community in the tailwaters of Glen Canyon Dam following long- and short-term experimentally induced desiccation. The response of Cladophora glomerata, Oscillatoria spp., miscellaneous phytobenthos species and periphyton was studied over 18 weeks using three treatments: (1) undisturbed control cobbles from the submerged zone; (2) cobbles desiccated and replaced into the submerged zone; and (3) cobbles desiccated and replaced into the varial zone. Periphyton density and compositional response resulting from these treatments were also examined. Desiccation treatments were significantly different in biomass from controls throughout the study. The biomass of desiccated...
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This dataset consists of fossil diatom counts from sediment cores collected in coastal environments on Montague Island, Alaska, and analyzed at Virginia Tech University.
In 1991, the U.S. Geological Survey (USGS) began a study of more than 50 major river basins across the Nation as part of the National Water-Quality Assessment (NAWQA) project of the National Water Quality Program. One of the major goals of the NAWQA project is to determine how water quality and ecological conditions change over time. To support that goal, long-term consistent and comparable ecological monitoring has been conducted on streams and rivers throughout the Nation. Fish, invertebrate, and algae data collected as part of the NAWQA program were retrieved from the USGS Aquatic Bioassessment database for use in trend analysis. Ultimately, these data will provide insight into how natural features and human...
Survival and size of mayflies at each life stage, as well as MeHg concentrations in diatoms and mayflies exposed to low and high MeHg concentrations and a range of selenomethione (SeMet) concentrations.
The diatom flora of selected sites in the Animas River Watershed, San Juan County, Colorado, was studied. Eighty diatom taxa were identified from 10 sites: 8 sites on the Animas River and 1 site each on the Cement and Cascade tributaries. The sample diatom abundance was dominated by Achnanthidium minutissimum, Encyonema silesiacum, Aulacoseira distans, Hannaea arcus, and Diatoma mesodon. The presence of teratologic specimens of Fragilaria and Achnanthidium in the samples indicated the possibility of metals contamination. Diatom diversity was low and Lange-Bertalot pollution index scores indicated little organic pollution evidenced from diatom composition. There was evidence that diatom composition at the sites was...
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The objective of this study was to assess the comparative influence of multiple stressors on benthic diatoms at 98 sites that spanned a range of stressors that occurred in an agricultural dominated region in the upper Midwest, USA. The primary stressors of interest included: nutrients, herbicides and fungicides, sediment, and streamflow; though the influence of physical habitat was incorporated in the assessment. The study area covered portions of 12 states (600,000 km2), with agriculture the dominate land use. The 98 sites used in this study consisted of 49 randomly selected EPA National Rivers and Streams Assessment sites combined with 49 targeted USGS sites. Thirty-seven of the targeted sites were selected to...
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Recent sediments from two alpine lakes (> 3300 m asl) in the Colorado Front Range (USA) register marked and near-synchronous changes that are believed to represent ecological responses to enhanced atmospheric deposition of fixed nitrogen from anthropogenic sources. Directional shifts in sediment proxies include greater representations of mesotrophic diatoms and increasingly depleted d15N values. These trends are particularly pronounced since ~ 1950, and appear to chronicle lake responses to excess N derived from agricultural and industrial sources to the east. The rate and magnitude of recent ecological changes far exceed the context of natural variability, as inferred from comparative analyses of a long core capturingthe...
In an effort to develop indicators for Great Lakes near-shore conditions, diatom-based transfer functions to infer water quality variables were developed from 155 samples collected from coastal Great Lakes wetlands, embayments and high-energy shoreline sites. Over 2,000 diatom taxa were identified, and 352 taxa were sufficiently abundant to include in transfer function development. Multivariate data exploration revealed strong responses of the diatom assemblages to stressor variables, including total phosphorus (TP). Spatial variables such as lake, latitude and longitude also had notable relationships with assemblage characteristics. A diatom inference transfer function for TP provided a robust reconstructive relationship...
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The safety, effectiveness and longevity of many construction and geotechnical engineering projects rely on correctly accounting for the evolution of soil properties over time. Critical sediment properties, such as compressibility, can change in response to pore-fluid chemistry changes, particularly if the sediment contains appreciable concentrations of fine-grained materials. Pore-fluid changes act at the micro scale, altering interactions between sediment particles, or between sediment particles and the pore fluid. These micro-scale alterations change how sediment fabrics and void ratios develop, which directly impacts macro-scale properties such as sediment compressibility. The goal of this study is to correlate...
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Detecting trends in biological attributes is central to many stream monitoring programs; however, understanding how natural variability in environmental factors affects trend results is not well understood. We evaluated the influence of antecedent streamflow and sample timing (covariates) on trend estimates for fish, invertebrate, and diatom taxa richness and biological condition from 2002 to 2012 at 51 sites distributed across the conterminous United States. This data release contains all of the input and output files necessary to reproduce the results presented and discussed in the associated journal article.
In 1991, the U.S. Geological Survey (USGS) began a study of more than 50 major river basins across the Nation as part of the National Water-Quality Assessment (NAWQA) project of the National Water Quality Program. One of the major goals of the NAWQA project is to determine how water quality and ecological conditions change over time. To support that goal, long-term consistent and comparable ecological monitoring has been conducted on streams and rivers throughout the Nation. Fish, invertebrate, and algae data collected as part of the NAWQA program were retrieved from the USGS Aquatic Bioassessment database for use in trend analysis. Ultimately, these data will provide insight into how natural features and human...
map background search result map search result map Anthropogenic nitrogen deposition induces rapid ecological changes in alpine lakes of the Colorado Front Range (USA) Ecological community datasets used to evaluate the presence of trends in ecological communities in selected rivers and streams across the United States, 1992-2012 (input) Data on Midwest stream diatom metrics and environmental stressors, 2013 2D micromodel studies of pore-throat clogging by pure fine-grained sediments and natural sediments from NGHP-02, offshore India Datasets used to evaluate the effects of antecedent streamflow and sample timing on trend assessments of fish, invertebrate and diatom communities across the United States, 2002-12 (output) 2008 - Present Ecosystem History of South Florida's Estuaries Database (ver. 2.0, June 2022) Mineralogic, grain-size, biologic, and stable isotopic analyses of core TOPGUN-SODA10 2A-K from Big Soda Lake, Nevada, USA Survival, growth, behavior and mercury concentrations of mayflies exposed to elevated dietary methylmercury and aqueous selenium Ecological community datasets used to evaluate the presence of trends in ecological communities in selected rivers and streams across the United States, 1992–2017 Ecological community datasets used to evaluate the presence of trends in ecological communities in selected rivers and streams across the United States, 1992–2017 (input) Dataset of diatom controls on the sedimentation behavior of fine-grained sediment collected offshore of South Korea during the Second Ulleung Basin Gas Hydrate Expedition, UBGH2 Radiocarbon measurements, census counts of benthic foraminifera, diatoms, and palynomorphs, and geochemistry from core 721-1 obtained in 2002 off San Francisquito Creek in South San Francisco Bay Census counts of diatoms from core 721-1 obtained in 2002 off San Francisquito Creek in South San Francisco Bay Diatom Data from Coastal Environments on Montague Island, Alaska Survival, growth, behavior and mercury concentrations of mayflies exposed to elevated dietary methylmercury and aqueous selenium Mineralogic, grain-size, biologic, and stable isotopic analyses of core TOPGUN-SODA10 2A-K from Big Soda Lake, Nevada, USA Diatom Data from Coastal Environments on Montague Island, Alaska Anthropogenic nitrogen deposition induces rapid ecological changes in alpine lakes of the Colorado Front Range (USA) Dataset of diatom controls on the sedimentation behavior of fine-grained sediment collected offshore of South Korea during the Second Ulleung Basin Gas Hydrate Expedition, UBGH2 Radiocarbon measurements, census counts of benthic foraminifera, diatoms, and palynomorphs, and geochemistry from core 721-1 obtained in 2002 off San Francisquito Creek in South San Francisco Bay 2D micromodel studies of pore-throat clogging by pure fine-grained sediments and natural sediments from NGHP-02, offshore India 2008 - Present Ecosystem History of South Florida's Estuaries Database (ver. 2.0, June 2022) Data on Midwest stream diatom metrics and environmental stressors, 2013 Ecological community datasets used to evaluate the presence of trends in ecological communities in selected rivers and streams across the United States, 1992–2017 Ecological community datasets used to evaluate the presence of trends in ecological communities in selected rivers and streams across the United States, 1992–2017 (input) Ecological community datasets used to evaluate the presence of trends in ecological communities in selected rivers and streams across the United States, 1992-2012 (input) Datasets used to evaluate the effects of antecedent streamflow and sample timing on trend assessments of fish, invertebrate and diatom communities across the United States, 2002-12 (output)