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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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Comparison of sediment composition by smear slides to quantitative shipboard data: A case study on the utility of smear slide percent estimates, IODP Expedition 353, northern Indian Ocean Comparison of sediment composition by smear slides to quantitative shipboard data: A case study on the utility of smear slide percent estimates, IODP Expedition 353, northern Indian Ocean
Smear slide petrography has been a standard technique during scientific ocean drilling expeditions to characterize sediment composition and classify sediment types, but presentation of these percent estimates to track downcore trends in sediment composition has become less frequent over the past 2 decades. We compare semi-quantitative smear slide composition estimates to physical...
Authors
Stephen C. Phillips, Kate Littler
Nekton community dynamics within active and inactive deltas in a major river estuary: Potential implications for altered hydrology regimes Nekton community dynamics within active and inactive deltas in a major river estuary: Potential implications for altered hydrology regimes
High fisheries production within estuaries is associated with coastal upwelling, tidal mixing, and land-based runoff facing increasing impacts from climate and human activities. Active river deltas receive large riverine inflows compared to inactive river deltas, providing contrasting estuaries to compare impacts of river inflow on estuarine nekton. We quantified nekton assemblages and...
Authors
Caleb B. Taylor, John Andrew Nyman, Megan K. La Peyre
Three decades of stranding data reveal insights into endangered hawksbill sea turtles in Hawai‘i Three decades of stranding data reveal insights into endangered hawksbill sea turtles in Hawai‘i
Hawksbill sea turtles Eretmochelys imbricata inhabiting the Hawaiian Islands are extremely rare and listed as endangered under the US Endangered Species Act. The paucity of data on basic hawksbill ecology continues to hinder effective management of the species. We analyzed stranding data collected between 1984 and 2018 to gain insights into the distribution, demography, and conservation...
Authors
Shandell Brunson, Alexander Gaos, Irene Kelly, Kyle van Houtan, Yonat Swimmer, Stacy Hargrove, George H. Balazs, Thierry M. Work, T. Todd Jones
A geochronological review of magmatism along the external margin of Columbia and in the Grenville-age orogens forming the core of Rodinia A geochronological review of magmatism along the external margin of Columbia and in the Grenville-age orogens forming the core of Rodinia
A total of 4344 magmatic U-Pb ages in the range 2300 to 800 Ma have been compiled from the Great Proterozoic Accretionary Orogen along the margin of the Columbia / Nuna supercontinent and from the subsequent Grenvillian collisional orogens forming the core of Rodinia. The age data are derived from Laurentia (North America and Greenland, n = 1212), Baltica (NE Europe, n = 1922), Amazonia...
Authors
Ake Johansson, Bernard Bingen, Hannu Huhma, Tod Waight, Rikke Vestergaard, Alvar Soesoo, Grazina Skridlaite, Ewa Krzeminska, Leonid Shumlyanskyy, Mark E. Holland, Christopher S. Holm-Denoma, Wilson Teixeira, Frederico Faleiros, Bruno Riberio, Joachim Jacobs, Cheng-Cheng Wang, Robert Thomas, Paul Macey, Christopher Kirkland, Michael Hartnady, Bruce Eglington, Stephen Puetz, Kent Condie
Pervasive, preferential flow through mega-thick unsaturated zones in the Southern Great Basin Pervasive, preferential flow through mega-thick unsaturated zones in the Southern Great Basin
Recharge from preferential flow through mega-thick (100–1,000 m) unsaturated zones is a pervasive phenomenon, as demonstrated with a case study of volcanic highland recharge areas in the Great Basin province in southern Nevada, USA. Statistically significant rising water-level trends occur for most study-area wells and resulted from a relatively wet period (1969–2005) in south-central...
Authors
Tracie R. Jackson, Joseph M. Fenelon, Seth Reilly Gainey
Behavioural adjustments in the social associations of a precocial shorebird mediate the costs and benefits of grouping decisions Behavioural adjustments in the social associations of a precocial shorebird mediate the costs and benefits of grouping decisions
Animals weigh multiple costs and benefits when making grouping decisions. The cost-avoidance grouping framework proposes that group density, information quality and risk affect an individual’s preference for con or heterospecific groups. However, this assumes the cost–benefit balance of a particular grouping is constant spatiotemporally, which may not always be true. Investigating how
Authors
Luke R. Wilde, Rose J. Swift, Nathan R. Senner
Gas hydrate saturation estimates, gas hydrate occurrence, and reservoir characteristics based on well log data from the hydrate-01 stratigraphic test well, Alaska North Slope Gas hydrate saturation estimates, gas hydrate occurrence, and reservoir characteristics based on well log data from the hydrate-01 stratigraphic test well, Alaska North Slope
The Hydrate-01 Stratigraphic Test Well was drilled at the Kuparuk 7-11-12 site on the Alaska North Slope in December 2018. Sonic log data provide compressional (P) and shear (S) slowness from which we determine gas hydrate saturation (Sgh) estimates using effective medium theory. The sonic Sgh estimates compare favorably with Sgh estimated from resistivity and nuclear magnetic resonance...
Authors
Seth S. Haines, Timothy Collett, Jun Yoneda, Naoyuki Shimoda, Ray Boswell, Norihiro Okinaka
Comparative toxicity of aquatic per- and polyfluoroalkyl substance exposure in three species of amphibians Comparative toxicity of aquatic per- and polyfluoroalkyl substance exposure in three species of amphibians
Per- and polyfluoroalkyl substances (PFAS) are contaminants of concern due to their widespread occurrence in the environment, persistence, and potential to elicit a range of negative health effects. Per- and polyfluoroalkyl substances are regularly detected in surface waters, but their effects on many aquatic organisms are still poorly understood. Species with thyroid-dependent...
Authors
Robert Wesley Flynn, Gary M. Hoover, Michael G. Iacchetta, Samuel C. Guffey, Youn J. Choi, Chloe De Perre, Belinda Huerta, Weiming Li, Jason T. Hoverman, Linda S. Lee, Maria S. Speulveda
Toward scoping reviews of individual bird species Toward scoping reviews of individual bird species
Scoping reviews, in which the literature on a given topic is systematically collated and summarized, aid literature searches and highlight knowledge gaps on a given topic, thus hastening scientific progress and informing conservation efforts. Because much research and conservation is targeted at the species level, ornithology and bird conservation would benefit from scoping reviews of...
Authors
Christopher J W McClure, Zackery Szymczycha, David L Anderson, Francisca Helena Aguiar-Silva, Sarah Schulwitz, Leah Dunn, MIchael T Henderson, Leticia Camacho, Jose de Jesus Vargas Gonzalez, Chris N. Parish, Evan R. Buechley, Jesse D’Elia, Sanford Wilbur, Kenneth Johansen, Devin L Johnson, Soren Moller, Ivan Pokrovsky, Todd E. Katzner
Site- and individual-level contaminations affect infection prevalence of an emerging infectious disease of amphibians Site- and individual-level contaminations affect infection prevalence of an emerging infectious disease of amphibians
Emerging infectious disease outbreaks are one of multiple stressors responsible for amphibian declines globally. In the northeastern United States, ranaviral diseases are prevalent in amphibians and other ectothermic species, but there is still uncertainty as to whether their presence is leading to population level effects. Further, there is also uncertainty surrounding the potential...
Authors
Kelly L. Smalling, Brittany A. Mosher, Luke R. Iwanowicz, Keith A. Loftin, Adam Boehlke, Michelle L. Hladik, Carly R. Muletz-Wolz, Nandadevi Cortes-Rodriguez, Robin Femmer, Evan H. Campbell Grant
By
Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Central Plains Water Science Center, Eastern Ecological Science Center, California Water Science Center, Geology, Geophysics, and Geochemistry Science Center, New Jersey Water Science Center
Assessing vegetation recovery from energy development using a dynamic reference approach Assessing vegetation recovery from energy development using a dynamic reference approach
Ecologically relevant references are useful for evaluating ecosystem recovery, but references that are temporally static may be less useful when environmental conditions and disturbances are spatially and temporally heterogeneous. This challenge is particularly acute for ecosystems dominated by sagebrush (Artemisia spp.), where communities may require decades to recover from disturbance...
Authors
Adrian P. Monroe, Travis W. Nauman, Cameron L. Aldridge, Michael S. O’Donnell, Michael C. Duniway, Brian S. Cade, Daniel Manier, Patrick J. Anderson
Face-off: Novel depredation and nest defense behaviors between an invasive and a native predator in the Greater Everglades Ecosystem, Florida, USA Face-off: Novel depredation and nest defense behaviors between an invasive and a native predator in the Greater Everglades Ecosystem, Florida, USA
We describe several photo-documented novel interactions between intraguild predators in southern Florida—the native bobcat (Lynx rufus) and the invasive Burmese python (Python bivittatus). Over several days we documented a bobcat's depredation of an unguarded python nest and subsequent python nest defense behavior following the return of both animals to the nest. This is the first...
Authors
Andrea Faye Currylow, Matthew F. McCollister, Gretchen Erika Anderson, Jillian Maureen Josimovich, Austin Lee Fitzgerald, Christina M. Romagosa, Amy A. Yackel Adams