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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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Sonoran desert tortoise: Gopherus morafkai Sonoran desert tortoise: Gopherus morafkai
Sonoran Desert Tortoise Gopherus morafkai has most recently been assessed for The IUCN Red List of Threatened Species in 2019. Gopherus morafkai is listed as Vulnerable under criteria A2abce+4abce.
Authors
R.C. Averill-Murray, P.C. Rosen, C.A. Jones, T.R. Jones, R. A. Lara-Resendiz, Taylor Edwards, A. Karl, Kristin H. Berry
Modeling extreme water levels in the Salish Sea: The importance of including remote sea level anomalies for application in hydrodynamic simulations Modeling extreme water levels in the Salish Sea: The importance of including remote sea level anomalies for application in hydrodynamic simulations
Extreme water-level recurrence estimates for a complex estuary using a high-resolution 2D model and a new method for estimating remotely generated sea level anomalies (SLAs) at the model boundary have been developed. The hydrodynamic model accurately resolves the dominant physical processes contributing to extreme water levels across the Washington State waters of the Salish Sea...
Authors
Eric E. Grossman, Babak Tehranirad, Kees Nederhoff, Sean Crosby, Andrew W. Stevens, Nathan R. VanArendonk, Daniel J. Nowacki, Li H. Erikson, Patrick L. Barnard
A simple approach to modeling light attenuation in the Sacramento-San Joaquin Delta using commonly available data A simple approach to modeling light attenuation in the Sacramento-San Joaquin Delta using commonly available data
The diffuse attenuation coefficient of photosynthetically active radiation (KdPAR) is commonly used to predict light attenuation in aquatic productivity models, but obtaining measurements of PAR to compute KdPAR is difficult. In situ calculations of KdPAR require multiple measurements of PAR through the water column, and these measurements are infeasible for real-time recording. Instead
Authors
Emily T. Richardson, Keith Bouma-Gregson, Katy O’Donnell, Brian A. Bergamaschi
Comparison of δ13C analyses of individual foraminifer (Orbulina universa) shells by secondary ion mass spectrometry and gas source mass spectrometry Comparison of δ13C analyses of individual foraminifer (Orbulina universa) shells by secondary ion mass spectrometry and gas source mass spectrometry
Rationale: The use of secondary ion mass spectrometry (SIMS) to perform micrometer-scale in situ carbon isotope (δ13C) analyses of shells of marine microfossils called planktic foraminifers holds promise to explore calcification and ecological processes. The potential of this technique, however, cannot be realized without comparison to traditional whole-shell δ13C values measured by gas...
Authors
Jody Brae Wycech, Daniel Clay Kelly, Reinhard Kozdon, Akizumi Ishida, Kouki Kitajima, Howard J. Spero, John W. Valley
Bridging the gap between mathematical biology and undergraduate education using applicable natural resource modeling Bridging the gap between mathematical biology and undergraduate education using applicable natural resource modeling
Mathematical biology is a wide field of study with many venues that undergraduate students can access through research. However, the topics of study for these students can be overwhelming, and many topics of study yield either only trivial results or abstract outcomes that are nonintuitive and diffcult to understand. We have used natural resource modeling, and more specifically, a...
Authors
Richard A. Erickson, Douglas Baumann, Barbara Bennie, Wako Bungula, Aaron R. Cupp, James E. Diffendorfer, Eric A. Eager, Roger J. Haro, Kathi Jo Jankowski, Danelle M. Larson, Greg J. Sandland, Molly Van Appledorn, James P Peirce
Insights into glendonite formation from the upper Oligocene Sagavanirktok Formation, North Slope, Alaska Insights into glendonite formation from the upper Oligocene Sagavanirktok Formation, North Slope, Alaska
The type locality for the upper Oligocene Nuwok Member of the Sagavanirktok Formation (Carter Creek, North Slope, Alaska, USA) contains abundant occurrence of glendonite, a pseudomorph after the calcium carbonate mineral ikaite, which typically forms in the shallow subsurface of cold marine sediments. The region during the time of Nuwok Member deposition was located at a high latitude...
Authors
John W. Counts, Madeleine Vickers, Martha Stokes, Whittney Spivey, Kristina Frank Gardner, Jean Self-Trail, Jared T. Gooley, Ryan J. McAleer, Aaron M. Jubb, David W. Houseknecht, Richard O. Lease, Neil Patrick Griffis, Martin S. Vickers, Kasia Sliwinska, Hannah Gail Dooley Tompkins, Adam M. Hudson
A continuous classification of the 476,697 lakes of the conterminous US based on geographic archetypes A continuous classification of the 476,697 lakes of the conterminous US based on geographic archetypes
A variety of classification approaches are used to facilitate understanding, prediction, monitoring, and the management of lakes. However, broad-scale applicability of current approaches is limited by either the need for in situ lake data, incompatibilities among approaches, or a lack of empirical testing of approaches based on ex situ data. We developed a new geographic classification...
Authors
Jean-Francois Lapierre, Katherine E. Webster, Ephraim Hanks, Tyler Wagner, Patricia A. Soranno, Ian M. McCullough, Kaitlin L. Reinl, Marcella Domka, Noah R. Lotting
Aging, climate, and invasions threaten reservoirs in the Mississippi basin Aging, climate, and invasions threaten reservoirs in the Mississippi basin
Reservoirs in the Mississippi River basin are facing three momentous threats. The first two, aging and climate change, are relatively slow moving and their signal can be hard to discern given their stretched temporal scales. The third, species invasions, is faster paced and discernable within shorter temporal scales and restricted spatial scales. Aging and climate directly affect...
Authors
Leandro E. Miranda
Book review of America’s public lands: From Yellowstone to Smokey Bear and beyond (2nd edition) Book review of America’s public lands: From Yellowstone to Smokey Bear and beyond (2nd edition)
Since the creation of the first public lands in the United States, they have been a source of turmoil, admiration, and prolonged political debate Nevertheless, our public lands have become an intrinsic part of our national identity and economic progress, exemplifying our divergent attitudes towards nature preservation and resource development. With this in mind, Randall K. Wilson makes a...
Authors
Ambar A. Melendez Perez, Denisse Camarena, Johanna M. H. Ford, Lindsey A. W. Gapinski, Anne M. Hatch, Brier E. Klossing, Aaron A. Yappert, Robert W. Klaver
Expansion of smallmouth bass distribution and habitat overlap with juvenile Chinook salmon in the Willamette River, Oregon Expansion of smallmouth bass distribution and habitat overlap with juvenile Chinook salmon in the Willamette River, Oregon
Smallmouth bass populations have expanded far beyond their native range and these predatory fish present a pervasive threat to native aquatic species throughout North America. In the western United States, smallmouth bass are now present in river and reservoir habitats where Pacific salmon are found and are considered a potential threat to salmon recovery in many locations. We conducted...
Authors
James White, Tobias J. Kock, Brooke E. Penaluna, Stanley V. Gregory, Joshua E. Williams, Randy Wildman
Diversification of forest management can mitigate wind damage risk and maintain biodiversity Diversification of forest management can mitigate wind damage risk and maintain biodiversity
Mitigating future forest risks, safeguarding timber revenues and improving biodiversity are key considerations for current boreal forest management. Alternatives to rotation forestry likely have an important role, but how they will perform under a changing climate remains unclear. We used a boreal forest growth simulator to explore how variations on traditional clear-cutting, in rotation...
Authors
Maria Potterf, Kyle Eyvindson, Clemens Blattert, Maria Trivino, Ryan C. Burner, Daniel Burgas, Mikko Monkkonen
Hawksbill and green turtle niche overlap in a marine protected area, US Virgin Islands Hawksbill and green turtle niche overlap in a marine protected area, US Virgin Islands
Studying how species interact with their environment and other co-occurring species are 2 main aspects of ecology. For marine turtles, ocean currents drive migratory routes and may determine the location of surrounding foraging grounds. As a result, circumglobal species like the hawksbill turtle Eretmochelys imbricata and green turtle Chelonia mydas adapt to diverse foraging habitats and...
Authors
Melissa A. Moorehouse, John D. Baldwin, Kristen Hart