Skip to main content
U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Results

165626 results.

Alternate formats: RIS file of the first 3000 search results  |  Download all results as CSV | TSV | Excel  |  RSS feed based on this search  |  JSON version of this page of results

Page 1745, results 43601 - 43625

Show results on a map

Publication Extents

Not all publications have extents, not all extents are completely accurate
Winter distribution of willow flycatcher subspecies
E. H. Paxton, P. Unitt, M. K. Sogge, M. Whitfield, P. Keim
2011, Condor (113) 608-618
Documenting how different regions across a species' breeding and nonbreeding range are linked via migratory movements is the first step in understanding how events in one region can influence events in others and is critical to identifying conservation threats throughout a migratory animal's annual cycle. We combined two studies that...
Phenology for science, resource management, decision making, and education
V.P. Nolan, J.F. Weltzin
2011, Conference Paper, Eos
Fourth USA National Phenology Network (USA-NPN) Research Coordination Network (RCN) Annual Meeting and Stakeholders Workshop; Milwaukee, Wisconsin, 21-22 September 2010; Phenology, the study of recurring plant and animal life cycle events, is rapidly emerging as a fundamental approach for understanding how ecological systems respond to environmental variation and climate change....
Downhole well log and core montages from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope
Timothy S. Collett, R.E. Lewis, William J. Winters, Myung W. Lee, K.K. Rose, R.M. Boswell
2011, Marine and Petroleum Geology (28) 561-577
The BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well was an integral part of an ongoing project to determine the future energy resource potential of gas hydrates on the Alaska North Slope. As part of this effort, the Mount Elbert well included an advanced downhole geophysical logging program. Because gas...
Estimating trends in alligator populations from nightlight survey data
Ikuko Fujisaki, F.J. Mazzotti, R.M. Dorazio, Kenneth G. Rice, M. Cherkiss, B. Jeffery
2011, Wetlands (31) 147-155
Nightlight surveys are commonly used to evaluate status and trends of crocodilian populations, but imperfect detection caused by survey- and location-specific factors makes it difficult to draw population inferences accurately from uncorrected data. We used a two-stage hierarchical model comprising population abundance and detection probability to examine recent abundance trends...
Microbial survival in the stratosphere and implications for global dispersal
David J. Smith, Dale W. Griffin, Richard D. McPeters, Peter D. Ward, Andrew C. Schuerger
2011, Aerobiologia (27) 319-332
Spores of Bacillus subtilis were exposed to a series of stratosphere simulations. In total, five distinct treatments measured the effect of reduced pressure, low temperature, high desiccation, and intense ultraviolet (UV) irradiation on stratosphereisolated and ground-isolated B. subtilis strains. Environmental conditions were based on springtime data from a mid-latitude region...
Invertebrate availability and vegetation characteristics explain use of nonnesting cover types by mature-forest songbirds during the postfledging period
Henry M. Streby, Sean M. Peterson, David E. Andersen
2011, Journal of Field Ornithology (82) 406-414
Some species of mature‐forest‐nesting songbirds use regenerating clearcuts and forested wetlands during the postfledging period (between nesting and migration). Relatively dense vegetation structure and abundant food resources in non‐mature‐forest cover types have been hypothesized to explain this phenomenon. We examined the relative importance of vegetation structure and invertebrate availability on...
Mysis diluviana population and cohort dynamics in Lake Ontario before and after the establishment of Dreissena spp., Cercopagis pengoi, and Bythotrephes longimanus
Ora E. Johannsson, Kelly L. Bowen, Kristen T. Holeck, Maureen G. Walsh
2011, Canadian Journal of Fisheries and Aquatic Sciences (68) 795-811
We investigated population responses of Mysis to ecosystem changes induced by invasion of dreissenids and predatory cladocerans, Cercopagis and Bythotrephes. Lake productivity declined as dreissenids invaded the offshore region. Whole-lake mysid biomass was compared before (early 1990s) and after (2002–2007) the invasion period; it declined 40%–45%. Abundance of young mysids...
Correlation between deep fluids, tremor and creep along the central San Andreas fault
M. Becken, O. Ritter, P. A. Bedrosian, U. Weckmann
2011, Nature (480) 87-90
The seismicity pattern along the San Andreas fault near Parkfield and Cholame, California, varies distinctly over a length of only fifty kilometres. Within the brittle crust, the presence of frictionally weak minerals, fault-weakening high fluid pressures and chemical weakening are considered possible causes of an anomalously weak fault northwest of...
Growth rate and age distribution of deep-sea black corals in the Gulf of Mexico
N.G. Prouty, E.B. Roark, N.A. Buster, Steve W. Ross
2011, Marine Ecology Progress Series (423) 101-115
Black corals (order Antipatharia) are important long-lived, habitat-forming, sessile, benthic suspension feeders that are found in all oceans and are usually found in water depths greater than 30 m. Deep-water black corals are some of the slowest-growing, longest-lived deep-sea corals known. Previous age dating of a limited number of black...
Differential effects of dissolved organic carbon upon re-entrainment and surface properties of groundwater bacteria and bacteria-sized microspheres during transport through a contaminated, sandy aquifer
Ronald W. Harvey, D.W. Metge, A. Mohanram, X. Gao, J. Chorover
2011, Environmental Science & Technology (45) 3252-3259
Injection-and-recovery studies involving a contaminated, sandy aquifer (Cape Cod, Massachusetts) were conducted to assess the relative susceptibility for in situ re-entrainment of attached groundwater bacteria (Pseudomonas stuzeri ML2, and uncultured, native bacteria) and carboxylate-modified microspheres (0.2 and 1.0 μm diameters). Different patterns of re-entrainment were evident for the two colloids...
Using Lagrangian sampling to study water quality during downstream transport in the San Luis Drain, California, USA
E.C. Volkmar, R.A. Dahlgren, W.T. Stringfellow, S.S. Henson, S.E. Borglin, C. Kendall, E. E. Van Nieuwenhuyse
2011, Chemical Geology (283) 68-77
To investigate the mechanism for diel (24h) changes commonly observed at fixed sampling locations and how these diel changes relate to downstream transport in hypereutrophic surface waters, we studied a parcel of agricultural drainage water as it traveled for 84h in a concrete-lined channel having no additional water inputs or...
Productivity of a coral reef using boundary layer and enclosure methods
W. R. McGillis, C. Langdon, B. Loose, Kimberly K. Yates, J. Corredor
2011, Geophysical Research Letters (38)
The metabolism of Cayo Enrique Reef, Puerto Rico, was studied using in situ methods during March 2009. Benthic O2 fluxes were used to calculate net community production using both the boundary layer gradient and enclosure techniques. The boundary layer O2 gradient and the drag coefficients were used to calculate productivity...
Accuracy of estimating wolf summer territories by daytime locations
D. J. Demma, L. David Mech
2011, American Midland Naturalist (165) 436-445
We used locations of 6 wolves (Canis lupus) in Minnesota from Global Positioning System (GPS) collars to compare day-versus-night locations to estimate territory size and location during summer. We employed both minimum convex polygon (MCP) and fixed kernel (FK) methods. We used two methods to partition GPS locations for...
Mapping the Philippines' mangrove forests using Landsat imagery
Jordan Long, Chandra Giri
2011, Sensors (11) 2972-2981
Current, accurate, and reliable information on the areal extent and spatial distribution of mangrove forests in the Philippines is limited. Previous estimates of mangrove extent do not illustrate the spatial distribution for the entire country. This study, part of a global assessment of mangrove dynamics, mapped the spatial distribution and...
Potential for iron oxides to control metal releases in CO2 sequestration scenarios
P.M. Berger, William R. Roy
2011, Energy Procedia (4) 3195-3201
The potential for the release of metals into groundwater following the injection of carbon dioxide (CO2) into the subsurface during carbon sequestration projects remains an open research question. Changing the chemical composition of even the relatively deep formation brines during CO2 injection and storage may be of concern because of the...
From intuition to statistics in building subsurface structural models
J.P. Brandenburg, F.O. Alpak, S. Naruk, J. Solum
2011, World Oil (232) 97-101
Experts associated with the oil and gas exploration industry suggest that combining forward trishear models with stochastic global optimization algorithms allows a quantitative assessment of the uncertainty associated with a given structural model. The methodology is applied to incompletely imaged structures related to deepwater hydrocarbon reservoirs and results are compared...
A 50-year record of NOx and SO2 sources in precipitation in the Northern Rocky Mountains, USA
David L. Naftz, Paul F. Schuster, Craig A. Johnson
2011, Geochemical Transactions (12)
Ice-core samples from Upper Fremont Glacier (UFG), Wyoming, were used as proxy records for the chemical composition of atmospheric deposition. Results of analysis of the ice-core samples for stable isotopes of nitrogen (δ15N, ) and sulfur (δ34S, ), as well as  and <img src="https://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1467-4866-12-4/MediaObjects/12932_2010_Article_115_IEq2_HTML.gif" alt=""...
Wintering bird response to fall mowing of herbaceous buffers
P.J. Blank, J.R. Parks, G.P. Dively
2011, Wilson Journal of Ornithology (123) 59-64
Herbaceous buffers are strips of herbaceous vegetation planted between working agricultural land and streams or wetlands. Mowing is a common maintenance practice to control woody plants and noxious weeds in herbaceous buffers. Buffers enrolled in Maryland's Conservation Reserve Enhancement Program (CREP) cannot be mowed during the primary bird nesting season...
Evaluation of groundwater discharge into small lakes based on the temporal distribution of radon-222
N. T. Dimova, W. C. Burnett
2011, Limnology and Oceanography (56) 486-494
In order to evaluate groundwater discharge into small lakes we constructed a model that is based on the budget of 222Rn (radon, t1/2=3.8 d) as a tracer. The main assumptions in our model are that the lake's waters are well‐mixed horizontally and vertically; the only significant 222Rn source is via groundwater discharge;...
Role of the fish astyanax aeneus (Characidae) as a keystone nutrient recycler in low-nutrient neotropical streams
G. E. Small, C. M. Pringle, M. Pyron, J.H. Duff
2011, Ecology (92) 386-397
Nutrient recycling by animals is a potentially important biogeochemical process in both terrestrial and aquatic ecosystems. Stoichiometric traits of individual species may result in some taxa playing disproportionately important roles in the recycling of nutrients relative to their biomass, acting as keystone nutrient recyclers. We examined factors controlling the relative...
Using multilevel spatial models to understand salamander site occupancy patterns after wildfire
Nathan Chelgren, M. J. Adams, Larissa L. Bailey, R. Bruce Bury
2011, Ecology (92) 408-421
Studies of the distribution of elusive forest wildlife have suffered from the confounding of true presence with the uncertainty of detection. Occupancy modeling, which incorporates probabilities of species detection conditional on presence, is an emerging approach for reducing observation bias. However, the current likelihood modeling framework is restrictive for handling...
Use of fatty acid analysis to determine dispersal of Caspian Terns in the Columbia River Basin, U.S.A.
C. J. Maranto, J. K. Parrish, D. P. Herman, A. E. Punt, J. D. Olden, M. T. Brett, Daniel D. Roby
2011, Conservation Biology (25) 736-746
Lethal control, which has been used to reduce local abundances of animals in conflict with humans or with endangered species, may not achieve management goals if animal movement is not considered. In populations with emigration and immigration, lethal control may induce compensatory immigration, if the source of attraction remains unchanged....
Effects of wind energy production on growth, demography, and survivorship of a Desert Tortoise (Gopherus agassizii) population in Southern California with comparisons to natural populations
J.E. Lovich, J.R. Ennen, S. Madrak, K. Meyer, C. Loughran, C. Bjurlin, T. Arundel, W. Turner, C. Jones, G.M. Groenendaal
2011, Herpetological Conservation and Biology (6) 161-174
We studied a Desert Tortoise (Gopherus agassizii) population at a large wind energy generation facility near Palm Springs, California over six field seasons from 1997 to 2010. We compared growth and demographic parameters to populations living in less disturbed areas; as well as populations of the closely-related and newly-described G....
Alaska North Slope regional gas hydrate production modeling forecasts
S.J. Wilson, R.B. Hunter, Timothy S. Collett, S. Hancock, R. Boswell, B.J. Anderson
2011, Marine and Petroleum Geology (28) 460-477
A series of gas hydrate development scenarios were created to assess the range of outcomes predicted for the possible development of the “Eileen” gas hydrate accumulation, North Slope, Alaska. Production forecasts for the “reference case” were built using the 2002 Mallik production tests, mechanistic simulation, and geologic studies conducted...