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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Oklahoma State University–Stillwater1, Macquarie University2, University of Sydney3, University of Utah4, Max Planck Society5, University of Alberta6, University of California, Irvine7, University of New Mexico8, University of Nebraska–Lincoln9, United States Geological Survey10, University of Washington11, University of Arizona12, University of Sheffield13, University of Tasmania14, ETH Zurich15, University of California, Davis16, Los Alamos National Laboratory17, Nanchang Institute of Technology18, University of Wyoming19, Swedish University of Agricultural Sciences20, University of Coimbra21, United States Forest Service22, Northern Arizona University23, Swiss Federal Institute for Forest, Snow and Landscape Research24, University of São Paulo25, University of Oxford26, University of California, Santa Cruz27, Humboldt State University28, Fordham University29, Centre national de la recherche scientifique30, University of Edinburgh31, Hobart Corporation32, Spanish National Research Council33, University of Chile34, Idaho State University35, University of Basilicata36, Colorado State University37, United States Department of Agriculture38, University of Montana39, University of Delaware40, University of Western Ontario41, Duke University42, Sonora Institute of Technology43, Pacific Northwest National Laboratory44
TL;DR: It is shown that, across multiple tree species, loss of xylem conductivity above 60% is associated with mortality, while carbon starvation is not universal, indicating that evidence supporting carbon starvation was not universal.
Abstract: Widespread tree mortality associated with drought has been observed on all forested continents and global change is expected to exacerbate vegetation vulnerability. Forest mortality has implications for future biosphere-atmosphere interactions of carbon, water and energy balance, and is poorly represented in dynamic vegetation models. Reducing uncertainty requires improved mortality projections founded on robust physiological processes. However, the proposed mechanisms of drought-induced mortality, including hydraulic failure and carbon starvation, are unresolved. A growing number of empirical studies have investigated these mechanisms, but data have not been consistently analysed across species and biomes using a standardized physiological framework. Here, we show that xylem hydraulic failure was ubiquitous across multiple tree taxa at drought-induced mortality. All species assessed had 60% or higher loss of xylem hydraulic conductivity, consistent with proposed theoretical and modelled survival thresholds. We found diverse responses in non-structural carbohydrate reserves at mortality, indicating that evidence supporting carbon starvation was not universal. Reduced non-structural carbohydrates were more common for gymnosperms than angiosperms, associated with xylem hydraulic vulnerability, and may have a role in reducing hydraulic function. Our finding that hydraulic failure at drought-induced mortality was persistent across species indicates that substantial improvement in vegetation modelling can be achieved using thresholds in hydraulic function.
651 citations
650 citations
TL;DR: Multiple linear regression models indicated that for the complete assemblages and for most trophic and mobility guilds, a large part of the variability was explained by measures of holes in the substratum, with important contributions from measured substratum rugosity and depth.
649 citations
TL;DR: A workflow to evaluate cloud and cloud shadow masking algorithms using cloud validation masks manually derived from both Landsat 7 Enhanced Thematic Mapper Plus and Landsat 8 OLI/TIRS data is created, finding that CFMask, C code based on the Function of Mask (Fmask) algorithm, and its confidence bands have the best overall accuracy among the many algorithms tested using validation data.
648 citations
Washington University in St. Louis1, Cornell University2, California Institute of Technology3, Max Planck Society4, Search for extraterrestrial intelligence5, University of Nevada, Reno6, United States Geological Survey7, Arizona State University8, Lockheed Martin Corporation9, American Museum of Natural History10, Ames Research Center11, University of Chicago12, Space Science Institute13, Honeybee Robotics14, Smithsonian Institution15, Massachusetts Institute of Technology16, State University of New York System17, University of Mainz18, Harvard University19, Glenn Research Center20, Texas A&M University21, Ohio State University22, University of Copenhagen23, University of Tennessee24, Goddard Space Flight Center25, University of Arizona26, University of Alabama at Birmingham27
TL;DR: In this paper, the authors show that the surface enrichment is the result of a minor amount of transport and deposition by aqueous processes on the surface of olivine-bearing basalts.
Abstract: Spirit landed on the floor of Gusev Crater and conducted initial operations on soil covered, rock-strewn cratered plains underlain by olivine-bearing basalts. Plains surface rocks are covered by wind-blown dust and show evidence for surface enrichment of soluble species as vein and void-filling materials and coatings. The surface enrichment is the result of a minor amount of transport and deposition by aqueous processes. Layered granular deposits were discovered in the Columbia Hills, with outcrops that tend to dip conformably with the topography. The granular rocks are interpreted to be volcanic ash and/or impact ejecta deposits that have been modified by aqueous fluids during and/or after emplacement. Soils consist of basaltic deposits that are weakly cohesive, relatively poorly sorted, and covered by a veneer of wind blown dust. The soils have been homogenized by wind transport over at least the several kilometer length scale traversed by the rover. Mobilization of soluble species has occurred within at least two soil deposits examined. The presence of mono-layers of coarse sand on wind-blown bedforms, together with even spacing of granule-sized surface clasts, suggest that some of the soil surfaces encountered by Spirit have not been modified by wind for some time. On the other hand, dust deposits on the surface and rover deck have changed during the course of the mission. Detection of dust devils, monitoring of the dust opacity and lower boundary layer, and coordinated experiments with orbiters provided new insights into atmosphere-surface dynamics.
647 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 |