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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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Fluorine-rich mafic lower crust in the southern Rocky Mountains: The role of pre-enrichment in generating fluorine-rich silicic magmas and porphyry Mo deposits Fluorine-rich mafic lower crust in the southern Rocky Mountains: The role of pre-enrichment in generating fluorine-rich silicic magmas and porphyry Mo deposits
Fluorine-rich granites and rhyolites occur throughout the southern Rocky Mountains, but the origin of F-enrichment has remained unclear. We test if F-enrichment could be inherited from ancient mafic lower crust by: (1) measuring amphibole compositions, including F and Cl contents, of lower crustal mafic granulite xenoliths from northern Colorado to determine if they are unusually...
Authors
Joshua Mark Rosera, Ryan Edward Frazer, Ryan D. Mills, Kristin Jacob, Sean P. Gaynor, Drew S. Coleman, G. Lang Farmer
Changes in chemical occurrence, concentration, and bioactivity in the Colorado River before and after replacement of the Moab, Utah wastewater treatment plant Changes in chemical occurrence, concentration, and bioactivity in the Colorado River before and after replacement of the Moab, Utah wastewater treatment plant
Long-term (2010–19) water-quality monitoring on the Colorado River downstream from Moab Utah indicated the persistent presence of Bioactive Chemicals (BC), such as pesticides and pharmaceuticals. This stream reach near Canyonlands National Park provides critical habitat for federally endangered species. The Moab wastewater treatment plant (WWTP) outfall discharges to the Colorado River...
Authors
William A. Battaglin, Paul M. Bradley, Rebbecca Weissinger, Brett R. Blackwell, Jenna E. Cavallin, Daniel L. Villeneuve, Laura A. DeCicco, Julie Kinsey
Anaxyrus monfontanus (Hot Creek Toad). Reproduction Anaxyrus monfontanus (Hot Creek Toad). Reproduction
No abstract available.
Authors
Patrick M. Kleeman, Brian J. Halstead
The consequences of neglecting reservoir storage in national-scale hydrologic models: An appraisal of key streamflow statistics The consequences of neglecting reservoir storage in national-scale hydrologic models: An appraisal of key streamflow statistics
A better understanding of modeled streamflow errors related to basin reservoir storage is needed for large regions, which normally have many ungaged basins with reservoirs. We quantified the difference between modeled and observed streamflows for one process-based and three statistical-transfer hydrologic models, none of which explicitly accounted for reservoir storage. Streamflow...
Authors
Glenn A. Hodgkins, Thomas M. Over, Robert W. Dudley, Amy M. Russell, Jacob H. LaFontaine
Mapping stream and floodplain geomorphometry with the Floodplain and Channel Evaluation Tool Mapping stream and floodplain geomorphometry with the Floodplain and Channel Evaluation Tool
Broad-scale mapping of stream channel and floodplain geomorphic metrics is critical to improve the understanding of geomorphic change, biogeochemical processes, riverine habitat quality, and opportunities for management intervention. The Floodplain and Channel Evaluation Tool (FACET) was developed to provide an open-source tool for automated processing of digital elevation models (DEMs)...
Authors
Kristina G. Hopkins, Labeeb Ahmed, Peter R. Claggett, Samuel Lamont, Marina J. Metes, Gregory E. Noe
Pre-eruptive outgassing and pressurization, and post-fragmentation bubble nucleation, recorded by vesicles in breadcrust bombs from vulcanian activity at Guagua Pichincha Volcano, Ecuador Pre-eruptive outgassing and pressurization, and post-fragmentation bubble nucleation, recorded by vesicles in breadcrust bombs from vulcanian activity at Guagua Pichincha Volcano, Ecuador
Breadcrust bombs formed during Vulcanian eruptions are assumed to originate from the shallow plug or dome. Their rim to core texture reflects the competition between cooling and degassing timescales, which results in a dense crust with isolated vesicles contrasting with a highly vesicular vesicle network in the interior. Due to relatively fast quenching, the crust can shed light on pre-...
Authors
Mathieu Colombier, Michael Manga, Heather M. Wright, Benjamin Bernard, Rebecca deGraffenried, Francisco Caceres, Pablo Samaniego, Jeremie Vasseur, K Jakata, Paul Cook, Donald B. Dingwell
Timing of reproduction underlies fitness tradeoffs for a salmonid fish Timing of reproduction underlies fitness tradeoffs for a salmonid fish
Life history diversity is generated and maintained in part by density-dependent fitness tradeoffs that inhibit a single trait value from reaching fixation. While central to our understanding of evolution, demonstrating density dependence in the strength of fitness tradeoffs is difficult in natural systems. The timing of reproduction is a key life history trait that determines access to...
Authors
Jeffrey R Baldock, Robert Al-Chokhachy, Matthew R. Campbell, Annika W. Walters
Critical considerations for communicating environmental DNA science Critical considerations for communicating environmental DNA science
The economic and methodological efficiencies of environmental DNA (eDNA) based survey approaches provide an unprecedented opportunity to assess and monitor aquatic environments. However, instances of inadequate communication from the scientific community about confidence levels, knowledge gaps, reliability, and appropriate parameters of eDNA-based methods have hindered their uptake in
Authors
Eric D. Stein, Christopher L. Jerde, Elizabeth Allan, Adam Sepulveda, Cathryn Abbott, Melinda R. Baerwald, John Darling, Kelly D Goodwin, Rachel Meyer, Molly Timmers, Peter Thielen
Survival and growth of juvenile mussels in an outdoor pond after 28-day laboratory exposure to aqueous zinc Survival and growth of juvenile mussels in an outdoor pond after 28-day laboratory exposure to aqueous zinc
The extent to which effects seen in chronic toxicity studies in the laboratory affect mussel fitness later in life is poorly known. We examined juvenile Fatmucket (Lampsilis siliquoidea) survival and growth for 56 d following exposure to Zn in a laboratory bioassay. We conducted a 28-d chronic toxicity bioassay with 6-wk-old juvenile mussels exposed to a control and two Zn treatments...
Authors
Jeffery A. Steevens, James L. Kunz, Ning Wang, Christopher M. Barnhart, Serena Ciparis
MODFLOW as a configurable multi-model hydrologic simulator MODFLOW as a configurable multi-model hydrologic simulator
MODFLOW 6 is the latest in a line of six “core” versions of MODFLOW released by the U.S. Geological Survey. The MODFLOW 6 architecture supports incorporation of additional hydrologic processes, in addition to groundwater flow, and allows interaction between processes. The architecture supports multiple model instances and multiple types of models within a single simulation, a flexible...
Authors
Christian D. Langevin, Joseph D. Hughes, Alden M. Provost, Martijn J. Russcher, Sorab Panday
Landowner and biologist perceptions of game bird predators and management Landowner and biologist perceptions of game bird predators and management
Nest survival has been identified as one of the most influential vital rates causing population change in game birds, and depredation, often influenced by habitat loss and fragmentation, is the primary cause of nest failure of upland game birds. We were interested in quantifying and comparing the perspectives of landowners and biologists in South Dakota regarding complex predator-prey...
Authors
Samantha R. Fina, Larry M. Gigliotti, Aaron T. Pearse, Joshua D. Stafford
Virtual snow stakes: a new method for snow depth measurement at remote camera stations Virtual snow stakes: a new method for snow depth measurement at remote camera stations
Remote cameras are used to study demographics, ecological processes, and behavior of wildlife populations. Cameras have also been used to measure snow depth with physical snow stakes. However, concerns that physical instruments at camera sites may influence animal behavior limit installation of instruments to facilitate collecting such data. Given that snow depth data are inherently...
Authors
Kaitlyn M. Strickfaden, Marnie L. Behan, Adrienne M. Marshall, Leona K. Svancara, David Edward Ausband, Timothy E. Link