Institution
United States Geological Survey
Government•Reston, Virginia, United States•
About: United States Geological Survey is a government organization based out in Reston, Virginia, United States. It is known for research contribution in the topics: Population & Groundwater. The organization has 17899 authors who have published 51097 publications receiving 2479125 citations. The organization is also known as: USGS & US Geological Survey.
Topics: Population, Groundwater, Volcano, Aquifer, Fault (geology)
Papers published on a yearly basis
Papers
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TL;DR: W Wise development of groundwater resources requires a more complete understanding of these changes in flow and storage and of their effects on the terrestrial environment and on numerous surface-water features and their biota.
Abstract: The dynamic nature of groundwater is not readily apparent, except where discharge is focused at springs or where recharge enters sinkholes. Yet groundwater flow and storage are continually changing in response to human and climatic stresses. Wise development of groundwater resources requires a more complete understanding of these changes in flow and storage and of their effects on the terrestrial environment and on numerous surface-water features and their biota.
601 citations
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TL;DR: Deep metagenomic sequencing is used to determine the impact of thaw on microbial phylogenetic and functional genes, and relate these data to measurements of methane emissions, and construct the first draft genome from a complex soil metagenome, which corresponds to a novel methanogen.
Abstract: We employed deep metagenomic sequencing to determine the impact of thaw on microbial phylogenetic and functional genes and related this data to measurements of methane emissions. Metagenomics, the direct sequencing of DNA from the environment, allows for the examination of whole biochemical pathways and associated processes, as opposed to individual pieces of the metabolic puzzle. Our metagenome analyses revealed that during transition from a frozen to a thawed state there were rapid shifts in many microbial, phylogenetic and functional gene abundances and pathways. After one week of incubation at 5°C, permafrost metagenomes converged to be more similar to each other than while they were frozen. We found that multiple genes involved in cycling of C and nitrogen shifted rapidly during thaw. We also constructed the first draft genome from a complex soil metagenome, which corresponded to a novel methanogen. Methane previously accumulated in permafrost was released during thaw and subsequently consumed by methanotrophic bacteria. Together these data point towards the importance of rapid cycling of methane and nitrogen in thawing permafrost.
601 citations
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TL;DR: In this article, a set of climate change model simulations was selected and evaluated to investigate possible future climate changes in California, and the climate models whose simulations were the focus of the present study were from the Parallel Climate Model (PCM1) from NCAR and DOE and the NOAA Geophysical Fluid Dynamics Laboratory CM2.1 model (GFDL).
Abstract: To investigate possible future climate changes in California, a set of climate change model simulations was selected and evaluated. From the IPCC Fourth Assessment, simulations of twenty-first century climates under a B1 (low emissions) and an A2 (a medium-high emissions) emissions scenarios were evaluated, along with occasional comparisons to the A1fi (high emissions) scenario. The climate models whose simulations were the focus of the present study were from the Parallel Climate Model (PCM1) from NCAR and DOE, and the NOAA Geophysical Fluid Dynamics Laboratory CM2.1 model (GFDL). These emission scenarios and attendant climate simulations are not "predictions," but rather are a purposely diverse set of examples from among the many plausible climate sequences that might affect California in the next century. Temperatures over California warm significantly during the twenty-first century in each simulation, with end-of-century temperature increases from approximately +1.5°C under the lower emissions B1 scenario in the less responsive PCM1 to +4.5°C in the higher emissions A2 scenario within the more responsive GFDL model. Three of the simulations (all except the B1 scenario in PCM1) exhibit more warming in summer than in winter. In all of the simulations, most precipitation continues to occur in winter. Relatively small (less than ~10%) changes in overall precipitation are projected. The California landscape is complex and requires that model information be parsed out onto finer scales than GCMs presently offer. When downscaled to its mountainous terrain, warming has a profound influence on California snow accumulations, with snow losses that increase with warming. Consequently, snow losses are most severe in projections by the more responsive model in response to the highest emissions.
600 citations
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TL;DR: Fe(III)-reducing organisms can inhibit sulfate reduction and methane production by outcompeting sulfate reducers and methanogens for electron donors when Fe(III) is in a form that Fe( III)-red reducing organisms can readily reduce.
Abstract: Mechanisms for inhibition of sulfate reduction and methane production in the zone of Fe(III) reduction in sediments were investigated. Addition of amorphic iron(III) oxyhydroxide to sediments in which sulfate reduction was the predominant terminal electron-accepting process inhibited sulfate reduction 86 to 100%. The decrease in electron flow to sulfate reduction was accompanied by a corresponding increase in electron flow to Fe(III) reduction. In a similar manner, Fe(III) additions also inhibited methane production in sulfate-depleted sediments. The inhibition of sulfate reduction and methane production was the result of substrate limitation, because the sediments retained the potential for sulfate reduction and methane production in the presence of excess hydrogen and acetate. Sediments in which Fe(III) reduction was the predominant terminal electron-accepting process had much lower concentrations of hydrogen and acetate than sediments in which sulfate reduction or methane production was the predominant terminal process. The low concentrations of hydrogen and acetate in the Fe(III)-reducing sediments were the result of metabolism by Fe(III)-reducing organisms of hydrogen and acetate at concentrations lower than sulfate reducers or methanogens could metabolize them. The results indicate that when Fe(III) is in a form that Fe(III)-reducing organisms can readily reduce, Fe(III)-reducing organisms can inhibit sulfate reduction and methane production by outcompeting sulfate reducers and methanogens for electron donors.
598 citations
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TL;DR: In this article, modern subaerial sand beds deposited by major tsunamis and hurricanes were compared at trench, transect, and sub-regional spatial scales to evaluate which attributes are most useful for distinguishing the two types of deposits.
598 citations
Authors
Showing all 18026 results
Name | H-index | Papers | Citations |
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Derek R. Lovley | 168 | 582 | 95315 |
Steven Williams | 144 | 1375 | 86712 |
Thomas J. Smith | 140 | 1775 | 113919 |
Jillian F. Banfield | 127 | 562 | 60687 |
Kurunthachalam Kannan | 126 | 820 | 59886 |
J. D. Hansen | 122 | 975 | 76198 |
John P. Giesy | 114 | 1162 | 62790 |
David Pollard | 108 | 438 | 39550 |
Alan Cooper | 108 | 746 | 45772 |
Gordon E. Brown | 100 | 454 | 32152 |
Gerald Schubert | 98 | 614 | 34505 |
Peng Li | 95 | 1548 | 45198 |
Vipin Kumar | 95 | 614 | 59034 |
Susan E. Trumbore | 95 | 337 | 34844 |
Alfred S. McEwen | 92 | 624 | 28730 |