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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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Proposed standard weight (Ws) equation and length categories for Utah Chub Proposed standard weight (Ws) equation and length categories for Utah Chub

Condition indices, such as relative weight (Wr), provide a simple method for comparing length–weight relationships among populations. However, no standard weight (Ws) equation has been developed for Utah Chub Gila atraria, a species of important management focus in the Intermountain West. We obtained length–weight data for 30,541 Utah Chub from 24 populations in Idaho, Montana, Utah, and...
Authors
Aaron Black, Zach Beard, Jon Flinders, Michael C. Quist

Relative effectiveness of D-Frame dip nets, quatrefoil light traps, and towed ichthyoplankton nets for larval Muskellunge Relative effectiveness of D-Frame dip nets, quatrefoil light traps, and towed ichthyoplankton nets for larval Muskellunge

Muskellunge Esox masquinongy are large, predatory game fish whose association with shallow, complex habitats is well documented, particularly during early life stages. Despite this association, relatively little guidance exists regarding effective sampling of Muskellunge larvae and previous efforts to sample larval Muskellunge have been met with limited success. Therefore, our objective...
Authors
Jared E. Krebs, Ethan J. Brandt, Daniel J. Dembkowski, Daniel A. Isermann

Evaluating establishment of conservation practices in the Conservation Reserve Program across the central and western United States Evaluating establishment of conservation practices in the Conservation Reserve Program across the central and western United States

The U.S. Department of Agriculture's Conservation Reserve Program (CRP) is one of the largest private lands conservation programs in the United States, establishing perennial vegetation on environmentally sensitive lands formerly in agricultural production. Over its 35 year existence, the CRP has evolved to include diverse conservation practices (CPs) while concomitantly meeting its core...
Authors
Mark W. Vandever, Sarah K. Carter, Timothy J. Assal, Kenneth Elgersma, Ai Wen, Justin L. Welty, Robert S. Arkle, Rich Iovanna

Review: “Jacob’s Zoo”— How using Jacob’s method for aquifer testing leads to more intuitive understanding of aquifer characteristics Review: “Jacob’s Zoo”— How using Jacob’s method for aquifer testing leads to more intuitive understanding of aquifer characteristics

The interpretation of aquifer responses to pumping tests is an important tool for assessing aquifer geometry and properties, which are critical in the assessment of water resources or in environmental remediation. However, the responses of aquifers, measured by time-drawdown relationships in monitoring wells, are nonunique solutions that are affected by many factors. Jacob’s Zoo is a...
Authors
Hans-Olaf Pfannkuch, Howard D. Mooers, Donald I. Siegel, John J. Quinn, Donald O. Rosenberry, Scott C. Alexander

Local fruit availability and en route wind conditions are poor predictors of bird abundance and composition during fall migration in coastal Yucatán Peninsula Local fruit availability and en route wind conditions are poor predictors of bird abundance and composition during fall migration in coastal Yucatán Peninsula

In migratory stopover habitats, bird abundance and composition change on a near daily basis. On any given day, the local bird community should reflect local environmental conditions but also the environments that birds encountered previously along their migratory route. For example, during fall migration, the coast of the Yucatán Peninsula in Mexico receives birds that have just crossed...
Authors
Richard E Feldman, Antonio Celis-Murillo, Jill L. Deppe, Alfredo Dorantes-Euan

Maintenance of nest quality in Adélie penguins Pygoscelis adeliae: An additional benefit to life in the center Maintenance of nest quality in Adélie penguins Pygoscelis adeliae: An additional benefit to life in the center

In colonial seabirds, differences in the nesting or fledging success have been associated with differences in nest position within the breeding aggregation (subcolony): less successful nests are located on the periphery, with more successful nests closer to the center. For Pygoscelid penguins, central nests tend to be larger, with nest size being an indicator of individual quality...
Authors
Virginia Morandini, Katie M. Dugger, Amélie Lescroël, Annie Schmidt, Grant Ballard

HydroMet: A new code for automated objective optimization of hydrometeorological thresholds for landslide initiation HydroMet: A new code for automated objective optimization of hydrometeorological thresholds for landslide initiation

Landslide detection and warning systems are important tools for mitigation of potential hazards in landslide prone areas. Traditionally, warning systems for shallow landslides have been informed by rainfall intensity-duration thresholds. More recent advances have introduced the concept of hydrometeorological thresholds that are informed not only by rainfall, but also by subsurface...
Authors
Jacob L. Conrad, Michael D. Morphew, Rex L. Baum, Benjamin B. Mirus

Long-term African dust delivery to the eastern Atlantic Ocean from the Sahara and Sahel regions: Evidence from Quaternary paleosols on the Canary Islands, Spain Long-term African dust delivery to the eastern Atlantic Ocean from the Sahara and Sahel regions: Evidence from Quaternary paleosols on the Canary Islands, Spain

Africa is the most important source of dust in the world today and dust storms from that continent frequently deposit sediment on the nearby Canary Islands. Many investigators have inferred African dust inputs to Canary Islands paleosols based only on the presence of quartz. However, some local rocks do contain this mineral, so quartz alone is insufficient proof of dust deposition...
Authors
Daniel R. Muhs, Joaquín Meco, James R. Budahn, Gary L. Skipp, Kathleen R. Simmons, Mathew C. Baddock, J.T. Betancort, A. Lomoschitz

Assessing cyanobacterial frequency and abundance at surface waters near drinking water intakes across the United States Assessing cyanobacterial frequency and abundance at surface waters near drinking water intakes across the United States

This study presents the first large-scale assessment of cyanobacterial frequency and abundance of surface water near drinking water intakes across the United States. Public water systems serve drinking water to nearly 90% of the United States population. Cyanobacteria and their toxins may degrade the quality of finished drinking water and can lead to negative health consequences...
Authors
Megan Coffer, Blake A. Schaeffer, Katherine Foreman, Alex Porteous, Keith A. Loftin, Richard Stumpf, Jeremy Werdell, Erin Urquhart, Ryan Albert, John Darling

Metal accumulation varies with life history, size, and development of larval amphibians Metal accumulation varies with life history, size, and development of larval amphibians

Amphibian larvae are commonly used as indicators of aquatic ecosystem health because they are susceptible to contaminants. However, there is limited information on how species characteristics and trophic position influence contaminant loads in larval amphibians. Importantly, there remains a need to understand whether grazers (frogs and toads [anurans]) and predators (salamanders) provide
Authors
Kelly L. Smalling, Emily Bea Oja, Danielle M. Cleveland, Jon D Davenport, Collin A. Eagles-Smith, Evan H. Campbell Grant, Patrick M. Kleeman, Brian J. Halstead, Kenzi M Stemp, Brian J. Tornabene, Zachary J Bunnell, Blake R. Hossack

Exploring the potential of electrospray-Orbitrap for stable isotope analysis using nitrate as a model Exploring the potential of electrospray-Orbitrap for stable isotope analysis using nitrate as a model

Widely used isotope ratio mass spectrometers have limited capabilities to measure metabolites, drugs, or small polyatomic ions without the loss of structural isotopic information. A new approach has recently been introduced that uses electrospray ionization Orbitrap to measure multidimensional isotope signatures of intact polar compounds. Using nitrate as a model compound, this study...
Authors
Andreas Hilkert, J.K. Bohlke, Stanley J. Mroczkowski, Kyle L. Fort, Konstantin Aizikov, Xinchen T. Wang, Sebastian H. Kopf, Cajetan Neubauer

Experimental warming across a tropical forest canopy height gradient reveals minimal photosynthetic and respiratory acclimation Experimental warming across a tropical forest canopy height gradient reveals minimal photosynthetic and respiratory acclimation

Tropical forest canopies cycle vast amounts of carbon, yet we still have a limited understanding of how these critical ecosystems will respond to climate warming. We implemented in situ leaf-level + 3°C experimental warming from the understory to the upper canopy of two Puerto Rican tropical tree species, Guarea guidonia and Ocotea sintenisii. After approximately 1 month of continuous...
Authors
Kelsey R. Carter, Tana E. Wood, Sasha C. Reed, Kaylie M. Butts, Molly A. Cavaleri
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