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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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Glucocorticoid and glycemic responses to immune challenge in a viviparous snake afflicted with an emerging mycosis Glucocorticoid and glycemic responses to immune challenge in a viviparous snake afflicted with an emerging mycosis
Disease may be both a cause and consequence of stress, and physiological responses to infectious disease may involve stress coping mechanisms that have important fitness consequences. For example, glucocorticoid and glycemic responses may affect host fitness by altering resource allocation and use in hosts, and these responses may be affected by competing stressors. To better understand...
Authors
Craig M. Lind, Joseph Agugliaro, Jason Ortega, Jenna N. Palmisano, Jeffrey M. Lorch, Tran Truong, Terence M. Farrell
Vortex trapping of suspended sand grains over ripples Vortex trapping of suspended sand grains over ripples
Coastal hydrodynamics and morphodynamics integrate the effects of small-scale fluid-sediment interactions; yet, these small-scale processes are not well understood. To investigate sediment trapping by turbulent coherent structures or vortices, the transport of coarse sand over ripples was analyzed in a small-oscillatory flow tunnel with phase-separated Particle Image and Tracking...
Authors
Donya P. Frank-Gilchrist, Allison M. Penko, Margaret L. Palmsten, Joseph Calantoni
Detection and transport of environmental DNA from two federally endangered mussels Detection and transport of environmental DNA from two federally endangered mussels
Environmental DNA (eDNA) offers a novel approach to supplement traditional surveys and provide increased spatial and temporal information on species detection, and it can be especially beneficial for detecting at risk or threatened species with minimal impact on the target species. The transport of eDNA in lotic environments is an important component in providing more informed...
Authors
Brandon James Sansom, Dannise Vannesa Ruiz-Ramos, Nathan Thompson, Maura O Roberts, Zachary Taylor, Katie Ortiz, Jess W. Jones, Catherine A. Richter, Katy E. Klymus
Reproductive ecology and egg parasitism of the Samoan swallowtail butterfly Reproductive ecology and egg parasitism of the Samoan swallowtail butterfly
We investigated the reproductive ecology and effects of egg parasitism on the Samoan swallowtail butterfly (Papilio godeffroyi), which survives only on Tutuila Island, American Samoa, after having disappeared from the much larger islands of Upolu and Savai‘i in independent Samoa. During monthly surveys of its only known host plant, Micromelum minutum, across eight sites in 2013 and 2014...
Authors
Paul C. Banko, Mark A. Schmaedick, Robert W. Peck, Adam C. Miles, Niela Leifi
Egg size scales negatively with system size in a periodic fish species Egg size scales negatively with system size in a periodic fish species
Optimal egg size theory implies that female organisms balance between fecundity and individual offspring investment according to their environment. Past interspecific studies suggest that fishes in large marine systems generally produce smaller eggs than those in small freshwater systems. We tested whether intraspecific egg size variation reflected a similar pattern by comparing egg size...
Authors
Scott T Koenigbauer, Zachary S. Feiner, Benjamin Dickinson, Stephanie L. Shaw, Zoe Almeida, Mark Richard Dufour, Alexander James Gatch, Claire Schraidt, Tomas O. Hook
Seasonally varying contributions of contemporaneous and lagged sources of instream total nitrogen and phosphorus load across the Illinois River basin Seasonally varying contributions of contemporaneous and lagged sources of instream total nitrogen and phosphorus load across the Illinois River basin
Quantifying nutrient sources in streams, their temporal and spatial variability, and drivers of that variability can support effective water resources management. Yet a lack of data and modeling capabilities has previously prevented comprehensive quantification across both space and time. Here a dynamic SPARROW (Spatially Referenced Regressions on Watershed attributes) model that...
Authors
Noah M. Schmadel, Olivia L. Miller, Scott Ator, Matthew P. Miller, Gregory E. Schwarz, Dale M. Robertson, Andrew J. Sekellick, Kenneth D. Skinner, David A. Saad
Climate change and animal health. Climate change and animal health.
No abstract available.
Authors
Charles Rupprecht, Glenn R. Guntenspergen
Comparison of butorphanol-azaperone-medetomidine and nalbuphine-medetomidine-azaperone in free-ranging elk (Cervus canadensis) in Pennsylvania, USA Comparison of butorphanol-azaperone-medetomidine and nalbuphine-medetomidine-azaperone in free-ranging elk (Cervus canadensis) in Pennsylvania, USA
Chemical immobilization is commonly used to capture and handle free-ranging elk (Cervus canadensis). Butorphanol-azaperone-medetomidine (BAM) and nalbuphine-medetomidine-azaperone (NalMed-A) are compounded drug combinations that are lower-scheduled in the US than drugs historically used for elk immobilizations. We compared BAM and NalMed-A for immobilization of free-ranging elk using...
Authors
Avery M. Corondi, Justin D. Brown, Jeremiah E. Banfield, W. David Walter
The role of geography, diet, and host phylogeny on the gut microbiome in the Hawaiian honeycreeper radiation The role of geography, diet, and host phylogeny on the gut microbiome in the Hawaiian honeycreeper radiation
The animal gut microbiome can have a strong influence on the health, fitness, and behavior of its hosts. The composition of the gut microbial community can be influenced by factors such as diet, environment, and evolutionary history (phylosymbiosis). However, the relative influence of these factors is unknown in most bird species. Furthermore, phylosymbiosis studies have largely focused...
Authors
Maria Constantini, Elin Videvall, Jeffrey T. Foster, Matthew Medeiros, John Gillece, Eben H. Paxton, Lisa H. Crampton, Hannah Mounce, Alexander Wang, Robert C. Fleischer, Michael G. Campana, Floyd Reed
Characterizing the areal extent of PFAS contamination in fish species downgradient of AFFF source zones Characterizing the areal extent of PFAS contamination in fish species downgradient of AFFF source zones
Most monitoring programs next to large per- and polyfluoroalkyl substances (PFAS) sources focus on drinking water contamination near source zones. However, less is understood about how these sources affect downgradient hydrological systems and food webs. Here, we report paired PFAS measurements in water, sediment, and aquatic biota along a hydrological gradient away from source zones...
Authors
Heidi M. Pickard, Bridger J. Ruyle, Faiz Haque, John M. Logan, Denis R. LeBlanc, Simon Vojta, Elsie M. Sunderland
Direct measurements of firn-density evolution from 2016 to 2022 at Wolverine Glacier, Alaska Direct measurements of firn-density evolution from 2016 to 2022 at Wolverine Glacier, Alaska
Knowledge of snow and firn-density change is needed to use elevation-change measurements to estimate glacier mass change. Additionally, firn-density evolution on glaciers is closely connected to meltwater percolation, refreezing and runoff, which are key processes for glacier mass balance and hydrology. Since 2016, the U.S. Geological Survey Benchmark Glacier Project has recovered firn...
Authors
Max Stevens, Louis C. Sass, Caitlyn Florentine, Christopher J. McNeil, Emily Baker, Katherine Eleanore Bollen