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Institution

United States Geological Survey

GovernmentReston, 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.


Papers
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Journal ArticleDOI
TL;DR: Dimethyl sulfoxide (DMSO) and 90% acetone extracted equal amounts of chlorophyll from diatoms and blue-green algae, but DMSO was superior to 90%acetone for all green algae tested giving 2-60 times more chlorophyLL depending on the species as discussed by the authors.
Abstract: Dimethyl sulfoxide (DMSO) and 90% acetone extracted equal amounts of chlorophyll from diatoms and blue-green algae, but DMSO was superior to 90% acetone for all green algae tested giving 2–60 times more chlorophyll depending on the species. The absorbance spectra of pure chlorophyll a (and b) from 600 nm to 750 nm were identical whether dissolved in 90% acetone or a mixture of DMSO and 90% acetone (1:1 v/v). Thus, several equations for estimating chlorophyll concentration based on extinction in 90% acetone are applicable with this solvent.

507 citations

Journal ArticleDOI
TL;DR: Methine from dissociated gas hydrate may have little opportunity to affect global climate change, however, submarine geohazards caused by gas-hydrate dissociation are of immediate and increasing importance as humankind moves to exploit seabed resources in ever-deepening waters of coastal oceans.
Abstract: For almost 30 years. serious interest has been directed toward natural gas hydrate, a crystalline solid composed of water and methane, as a potential (i) energy resource, (ii) factor in global climate change, and (iii) submarine geohazard. Although each of these issues can affect human welfare, only (iii) is considered to be of immediate importance. Assessments of gas hydrate as an energy resource have often been overly optimistic, based in part on its very high methane content and on its worldwide occurrence in continental margins. Although these attributes are attractive, geologic settings, reservoir properties, and phase-equilibria considerations diminish the energy resource potential of natural gas hydrate. The possible role of gas hydrate in global climate change has been often overstated. Although methane is a “greenhouse” gas in the atmosphere, much methane from dissociated gas hydrate may never reach the atmosphere, but rather may be converted to carbon dioxide and sequestered by the hydrosphere/biosphere before reaching the atmosphere. Thus, methane from gas hydrate may have little opportunity to affect global climate change. However, submarine geohazards (such as sediment instabilities and slope failures on local and regional scales, leading to debris flows, slumps, slides, and possible tsunamis) caused by gas-hydrate dissociation are of immediate and increasing importance as humankind moves to exploit seabed resources in ever-deepening waters of coastal oceans. The vulnerability of gas hydrate to temperature and sea level changes enhances the instability of deep-water oceanic sediments, and thus human activities and installations in this setting can be affected.

507 citations

Journal ArticleDOI
13 Nov 1987-Science
TL;DR: Although analysis after the storms suggests that modifications and additional development are needed, the system successfully predicted the times of major landslide events and could be used as a prototype for systems in other landslide-prone regions.
Abstract: A real-time system for issuing warnings of landslides during major storms is being developed for the San Francisco Bay region, California. The system is based on empirical and theoretical relations between rainfall and landslide initiation, geologic determination of areas susceptible to landslides, real-time monitoring of a regional network of telemetering rain gages, and National Weather Service precipitation forecasts. This system was used to issue warnings during the storms of 12 to 21 February 1986, which produced 800 millimeters of rainfall in the region. Although analysis after the storms suggests that modifications and additional development are needed, the system successfully predicted the times of major landslide events. It could be used as a prototype for systems in other landslide-prone regions.

507 citations

Journal ArticleDOI
TL;DR: For the period from 1958 to 1996, streamflow characteristics of a highly urbanized watershed were compared with less-urbanized and nonurbanized watersheds within a 20000 km 2 region in the vicinity of Atlanta, Georgia: in the Piedmont and Blue Ridge physiographic provinces of the southeastern USA.
Abstract: For the period from 1958 to 1996, streamflow characteristics of a highly urbanized watershed were compared with less-urbanized and non-urbanized watersheds within a 20000 km 2 region in the vicinity of Atlanta, Georgia: in the Piedmont and Blue Ridge physiographic provinces of the southeastern USA. Water levels in several wells completed in surficial and crystalline-rock aquifers were also evaluated. Data were analysed for seven US Geological Survey (USGS) stream gauges, 17 National Weather Service rain gauges, and five USGS monitoring wells. Annual runoff coefficients (RCs; runoff as a fractional percentage of precipitation) for the urban stream (Peachtree Creek) were not significantly greater than for the less-urbanized watersheds. The RCs for some streams were similar to others and the similar streams were grouped according to location. The RCs decreased from the higher elevation and higher relief watersheds to the lower elevation and lower relief watersheds: values were 0! 54 for the two Blue Ridge streams, 0! 37 for the four middle Piedmont streams (near Atlanta), and 0! 28 for a southern Piedmont stream. For the 25 largest stormflows, the peak flows for Peachtree Creek were 30% to 100% greater than peak flows for the other streams. The storm recession period for the urban stream was 1‐2 days less than that for the other streams and the recession was characterized by a 2-day storm recession constant that was, on average, 40 to 100% greater, i.e. streamflow decreased more rapidly than for the other streams. Baseflow recession constants ranged from 35 to 40% lower for Peachtree Creek than for the other streams; this is attributed to lower evapotranspiration losses, which result in a smaller change in groundwater storage than in the less-urbanized watersheds. Low flow of Peachtree Creek ranged from 25 to 35% less than the other streams, possibly the result of decreased infiltration caused by the more efficient routing of stormwater and the paving of groundwater recharge areas. The timing of daily or monthly groundwater-level fluctuations was similar annually in each well, reflecting the seasonal recharge. Although water-level monitoring only began in the 1980s for the two urban wells, water levels displayed a notable decline compared with non-urban wells since then; this is attributed to decreased groundwater recharge in the urban watersheds due to increased imperviousness and related rapid storm runoff. Copyright ! 2001 John Wiley & Sons, Ltd.

507 citations

Book ChapterDOI
TL;DR: The term “specific inhibitor” has been applied to these types of compounds when they are used to probe the functions of mixed populations of microorganisms, providing powerful experimental tools for investigating the activity and function of certain types of micro organisms in natural samples.
Abstract: The above statement, although meant to be tongue in cheek, contains an essential truism: all work with inhibitors is inherently suspect. This fact has been known by biochemists for some time. However, use of chemical inhibitors of enzymic systems and membranes continues to be a common approach taken toward unraveling the biochemistry and biophysics of plants, animals, and microorganisms. Various types of “broad-spectrum” biochemical inhibitors (e.g., poisons, respiratory inhibitors, and uncouplers) have been employed by ecologists for many years in order to demonstrate the active participation of microbes in chemical reactions occurring in natural samples (e.g., soils, sediments, and water). In recent years, considerable advances have been made in our understanding of the biochemistry of microorganisms of biogeochemical interest. Concurrent with these advances have been the discoveries of novel types of compounds that will block the metabolism of one particular group of microbes, but have little disruptive effect on other physiological types. Thus, the term “specific inhibitor” has been applied to these types of compounds when they are used to probe the functions of mixed populations of microorganisms. These substances provide powerful experimental tools for investigating the activity and function of certain types of microorganisms in natural samples.

506 citations


Authors

Showing all 18026 results

NameH-indexPapersCitations
Derek R. Lovley16858295315
Steven Williams144137586712
Thomas J. Smith1401775113919
Jillian F. Banfield12756260687
Kurunthachalam Kannan12682059886
J. D. Hansen12297576198
John P. Giesy114116262790
David Pollard10843839550
Alan Cooper10874645772
Gordon E. Brown10045432152
Gerald Schubert9861434505
Peng Li95154845198
Vipin Kumar9561459034
Susan E. Trumbore9533734844
Alfred S. McEwen9262428730
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202367
2022224
20212,132
20202,082
20191,914
20181,920