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The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
Browse more than 65,000 articles authored by our scientists over the past 100+ year history of the USGS and refine search by topic, location, year, and advanced search.
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Hematology and biochemistry reference intervals for American alligator (Alligator mississippiensis) in South Florida, USA Hematology and biochemistry reference intervals for American alligator (Alligator mississippiensis) in South Florida, USA
We calculated reference intervals for 48 blood parameters from 120 wild American alligators (Alligator mississippiensis) in South Florida, US. Although previously reported by others, this study includes additional parameters not yet reported in wild populations. Most previously reported blood parameter values were similar to ours and fell within our reference intervals.
Authors
Laura A. Brandt, Nicole D. Jennings, Michiko A. Squires, Caitlin E. Hackett, Christopher D. Smith, Frank J. Mazzotti
Overview of the morphology and chemistry of diagenetic features in the clay-rich Glen Torridon Unit of Gale Crater, Mars Overview of the morphology and chemistry of diagenetic features in the clay-rich Glen Torridon Unit of Gale Crater, Mars
The clay-rich Glen Torridon region of Gale crater, Mars, was explored between sols 2300 and 3007. Here, we analyzed the diagenetic features observed by Curiosity, including veins, cements, nodules, and nodular bedrock, using the ChemCam, Mastcam, and Mars Hand Lens Imager instruments. We discovered many diagenetic features in Glen Torridon, including dark-toned iron- and manganese-rich...
Authors
Patrick J. Gasda, Jade Comellas, A Essunfeld, D. Das, Alex B Bryk, Erwin Dehouck, Susanne P. Schwenzer, Laura Crossey, Kenneth E. Herkenhoff, Jeffrey B. Johnson, Horton E. Newsom, Nina L. Lanza, William Rapin, Walter Goetz, Pierre-Yves Meslin, John C. Bridges, Ryan B. Anderson, Gael David, S M R Turner, M T Thorpe, Linda C. Kah, Jens Frydenvang, Rachel Kronyak, G. Caravaca, Ann M. Ollila, Stephane Le Mouelic, M Nellessen, Megan Hoffman, Deirdra M. Fey, Agnes Cousin, Roger C. Wiens, Sam M. Clegg, Sylvestre Maurice, Olivier Gasnault, Dorothy Delapp, A. Reyes-Newell
Population connectivity of aquatic insects in a dam-regulated, desert river Population connectivity of aquatic insects in a dam-regulated, desert river
Humans have exaggerated natural habitat fragmentation, negatively impacting species dispersal and reducing population connectivity. Habitat fragmentation can be especially detrimental in freshwater populations, whose dispersal is already constrained by the river network structure. Aquatic insects, for instance, are generally limited to two primary modes of dispersal: downstream drift in...
Authors
Erin F. Abernethy, Jeffrey Muehlbauer, Theodore Kennedy, Katie E. Dziedzic, Holland Elder, Molly K. Burke, David A. Lytle
The applicability of time-integrated unit stream power for estimating bridge pier scour using noncontact methods in a gravel-bed river The applicability of time-integrated unit stream power for estimating bridge pier scour using noncontact methods in a gravel-bed river
In near-field remote sensing, noncontact methods (radars) that measure stage and surface water velocity have the potential to supplement traditional bridge scour monitoring tools because they are safer to access and are less likely to be damaged compared with in-stream sensors. The objective of this study was to evaluate the use of radars for monitoring the hydraulic conditions that...
Authors
Laura A. Hempel, Helen F. Malenda, John W, Fulton, Mark F. Henneberg, Jay Cederberg, Tommaso Moramarco
Evaluating the risk of SARS-CoV-2 transmission to bats in the context of wildlife research, rehabilitation, and control Evaluating the risk of SARS-CoV-2 transmission to bats in the context of wildlife research, rehabilitation, and control
Preventing wildlife disease outbreaks is a priority for natural resource agencies, and management decisions can be urgent, especially in epidemic circumstances. With the emergence of SARS-CoV-2, wildlife agencies were concerned whether the activities they authorize might increase the risk of viral transmission from humans to North American bats, but had a limited amount of time in which...
Authors
Jonathan D. Cook, Evan H. Campbell Grant, Jeremy T. H. Coleman, Jonathan M. Sleeman, Michael C. Runge
Climate and landscape controls on old-growth western juniper demography in the northern Great Basin, USA Climate and landscape controls on old-growth western juniper demography in the northern Great Basin, USA
Western juniper (Juniperus occidentalis Hook.) woodlands have persisted for millennia in semiarid parts of the northern Great Basin, USA, providing critical habitat for plant and animal species. Historical records suggest that the establishment of western juniper is strongly associated with regional climatic variability. For example, the abundance of western juniper pollen and...
Authors
Rachel A. Loehman, Emily K. Heyerdahl, Gregory T. Pederson, David B. McWethy
Restoration for resilience: The role of plant-microbial interactions and seed provenance in ecological restoration Restoration for resilience: The role of plant-microbial interactions and seed provenance in ecological restoration
With global efforts to restore grassland ecosystems, researchers and land management practitioners are working to reconstruct habitat that will persist and withstand stresses associated with climate change. Part of these efforts involve movement of plant material potentially adapted to future climate conditions from native habitat or seed production locations to a new restoration site...
Authors
Jennifer Larson, Robert Venette, Diane L. Larson
Identification of supraoptimal temperatures in juvenile blueback herring (Alosa aestivalis) using survival, growth rate and scaled energy reserves Identification of supraoptimal temperatures in juvenile blueback herring (Alosa aestivalis) using survival, growth rate and scaled energy reserves
For young fishes, growth of somatic tissues and energy reserves are critical steps for survival and progressing to subsequent life stages. When thermal regimes become supraoptimal, routine metabolic rates increase and leave less energy for young fish to maintain fitness-based activities and, in the case of anadromous fishes, less energy to prepare for emigration to coastal habitats. Thus
Authors
Lian Guo, Adrian Jordaan, Eric T. Schultz, Stephen D. McCormick
Central Andean (28–34°S) flood record 0–25 ka from Salinas del Bebedero, Argentina Central Andean (28–34°S) flood record 0–25 ka from Salinas del Bebedero, Argentina
The Salinas del Bebedero occupies an isolated basin in the foreland of central Argentina at 33°S and was flooded repeatedly over past 25 ka. Isotopic evidence demonstrates that this flooding was due to overflow of the nearby Río Desaguadero with waters derived from the distant (≥300 km) central Andes between 28–34°S. Stratigraphic and shoreline evidence shows that floods occurred most...
Authors
Jay Quade, Elad Dente, Allison Cartwright, Adam M. Hudson, Sebastian Jimenez, David McGee
Integrated hydrologic model development and postprocessing for GSFLOW using pyGSFLOW Integrated hydrologic model development and postprocessing for GSFLOW using pyGSFLOW
pyGSFLOW is a python package designed to create new GSFLOW integrated hydrologic models, read existing models, edit model input data, run GSFLOW models, process output, and visualize model data.
Authors
Joshua Larsen, Ayman H. Alzraiee, Richard G. Niswonger
Population viability analysis for a pond-breeding amphibian under future drought scenarios in the southeastern United States Population viability analysis for a pond-breeding amphibian under future drought scenarios in the southeastern United States
Climate change effects are contributing to widespread declines of amphibians, and pond-breeding species may be particularly sensitive to future drought conditions that restrict wetland hydroperiods and decrease opportunities for successful breeding and recruitment. Pond-breeding amphibian populations can compensate for periodic droughts via episodic booms in recruitment, but studies...
Authors
Brian A. Crawford, John C. Maerz, Vanessa C. K. Terrell, Clinton T. Moore
Pre-breeding foraging ecology of three tern species nesting in the Gulf of Maine Pre-breeding foraging ecology of three tern species nesting in the Gulf of Maine
A variety of seabird species migrate annually from wintering grounds in the Southern Hemisphere to the Gulf of Maine, USA to breed and raise their young. Post-migration, adult seabirds depend on the spatio-temporal match of reliable food resources to replenish energy reserves before breeding. However, the conditions during this critical window of time are becoming increasingly uncertain...
Authors
Rachel M. Bratton, Henry Legett, Paula Shannon, Keenan Yakola, Alexander R. Gerson, Michelle Staudinger