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, Sediment
Papers published on a yearly basis
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TL;DR: In this article, 21 samples collected from a core of the 52.8 cm-thick Stark Shale Member of the Dennis Limestone in Wabaunsee County, Kansas, demonstrate four cycles with two-orders-of-magnitude variations in contents of Cd, Mo, P, V and Zn, and order-of magnitude variations in the contents of organic carbon, Cr, Ni, Se and U.
723 citations
TL;DR: The superposition of local flow systems associated with surface-water bodies on this regional framework results in complex interactions between groundwater and surface water in all landscapes, regardless of regional topographic position as mentioned in this paper.
Abstract: Surface-water bodies are integral parts of groundwater flow systems. Groundwater interacts with surface water in nearly all landscapes, ranging from small streams, lakes, and wetlands in headwater areas to major river valleys and seacoasts. Although it generally is assumed that topographically high areas are groundwater recharge areas and topographically low areas are groundwater discharge areas, this is true primarily for regional flow systems. The superposition of local flow systems associated with surface-water bodies on this regional framework results in complex interactions between groundwater and surface water in all landscapes, regardless of regional topographic position. Hydrologic processes associated with the surface-water bodies themselves, such as seasonally high surface-water levels and evaporation and transpiration of groundwater from around the perimeter of surface-water bodies, are a major cause of the complex and seasonally dynamic groundwater flow fields associated with surface water. These processes have been documented at research sites in glacial, dune, coastal, mantled karst, and riverine terrains.
721 citations
TL;DR: A method has been developed for the trace analysis of two classes of antimicrobials consisting of six sulfonamides and five tetracyclines, which commonly are used for veterinary purposes and agricultural feed additives and are suspected to leach into ground and surface water.
Abstract: A method has been developed for the trace analysis of two classes of antimicrobials consisting of six sulfonamides (SAs) and five tetracyclines (TCs), which commonly are used for veterinary purposes and agricultural feed additives and are suspected to leach into ground and surface water. The method used solid-phase extraction and liquid chromatography/mass spectrometry (LC/MS) with positive ion electrospray. The unique combination of a metal chelation agent (Na2EDTA) with a macroporous copolymer resulted in quantitative recoveries by solid-phase extraction (mean recovery, 98 ± 12%) at submicrogram-per-liter concentrations. An ammonium formate/formic acid buffer with a methanol/water gradient was used to separate the antimicrobials and to optimize the signal intensity. Mass spectral fragmentation and ionization characteristics were determined for each class of compounds for unequivocal identification. For all SAs, a characteristic m/z 156 ion representing the sulfanilyl fragment was identified. TCs exhibit...
721 citations
TL;DR: In this article, a vector ruggedness measure (VRM) of terrain based on a geomorphological method for measuring vector dispersion that is less correlated with slope was developed and the relationship of VRM to slope and to two commonly used indices of ruggedness in 3 physiographically different mountain ranges within the Mojave Desert of the southwestern United States.
Abstract: Terrain ruggedness is often an important variable in wildlife habitat models. Most methods used to quantify ruggedness are indices derived from measures of slope and, as a result, are strongly correlated with slope. Using a Geographic Information System, we developed a vector ruggedness measure (VRM) of terrain based on a geomorphological method for measuring vector dispersion that is less correlated with slope. We examined the relationship of VRM to slope and to 2 commonly used indices of ruggedness in 3 physiographically different mountain ranges within the Mojave Desert of the southwestern United States. We used VRM, slope, distance to water, and springtime bighorn sheep (Ovis canadensis nelsoni) adult female locations to model sheep habitat in the 3 ranges. Using logistic regression, we determined that the importance of ruggedness in habitat selection remained consistent across mountain ranges, whereas the relative importance of slope varied according to the characteristic physiography of each range. Our results indicate that the VRM quantifies local variation in terrain more independently of slope than other methods tested, and that VRM and slope distinguish 2 different components of bighorn sheep habitat.
719 citations
Goethe University Frankfurt1, University of Maryland, College Park2, University of Guelph3, Duke University4, Swedish University of Agricultural Sciences5, Radboud University Nijmegen6, Federal University of Mato Grosso do Sul7, University of Alberta8, Royal Veterinary College9, Wildlife Conservation Society10, Mississippi State University11, Sao Paulo State University12, Michigan Department of Natural Resources13, University of California, Davis14, Aarhus University15, Max Planck Society16, University of Potsdam17, Middle Tennessee State University18, Mammal Research Institute19, Harvard University20, Edmund Mach Foundation21, Smithsonian Conservation Biology Institute22, University of Évora23, University of Montpellier24, Monash University25, Parks Victoria26, Ohio State University27, Fiji National University28, University of Massachusetts Amherst29, United States Geological Survey30, University of Oxford31, Save the Elephants32, German Primate Center33, Technische Universität München34, Institute of Ecosystem Studies35, University of British Columbia36, University of Zurich37, University of Wyoming38, University of Washington39, University of Montana40, University of Freiburg41, Bavarian Forest National Park42, University of Toulouse43, University of Veterinary Medicine Vienna44, University College Cork45, North Carolina State University46, North Carolina Museum of Natural Sciences47, Karatina University48, University of Lethbridge49, Lamont–Doherty Earth Observatory50, University of Valencia51, Stony Brook University52, International Union for Conservation of Nature and Natural Resources53, University of Alicante54, Empresa Brasileira de Pesquisa Agropecuária55, University of Glasgow56, New York University57, University of Oslo58, Hebrew University of Jerusalem59, Norwegian University of Science and Technology60, Field Museum of Natural History61, University of Grenoble62, University of Bayreuth63, University of New South Wales64, Pennsylvania Game Commission65, Princeton University66, University of Konstanz67, University of Haifa68, Polish Academy of Sciences69, University of Lisbon70, Instituto Superior de Agronomia71, University of Porto72, University of California, Santa Cruz73, University of Pretoria74, Colorado State University75
TL;DR: Using a unique GPS-tracking database of 803 individuals across 57 species, it is found that movements of mammals in areas with a comparatively high human footprint were on average one-half to one-third the extent of their movements in area with a low human footprint.
Abstract: Animal movement is fundamental for ecosystem functioning and species survival, yet the effects of the anthropogenic footprint on animal movements have not been estimated across species. Using a unique GPS-tracking database of 803 individuals across 57 species, we found that movements of mammals in areas with a comparatively high human footprint were on average one-half to one-third the extent of their movements in areas with a low human footprint. We attribute this reduction to behavioral changes of individual animals and to the exclusion of species with long-range movements from areas with higher human impact. Global loss of vagility alters a key ecological trait of animals that affects not only population persistence but also ecosystem processes such as predator-prey interactions, nutrient cycling, and disease transmission.
719 citations
Authors
Showing all 18026 results
| Name | H-index | Papers | Citations |
|---|---|---|---|
| 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 |