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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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Geographic drivers of mercury entry into aquatic food webs revealed by mercury stable isotopes in dragonfly larvae Geographic drivers of mercury entry into aquatic food webs revealed by mercury stable isotopes in dragonfly larvae
Atmospheric mercury (Hg) emissions and subsequent transport and deposition are major concerns within protected lands, including national parks, where Hg can bioaccumulate to levels detrimental to human and wildlife health. Despite this risk to biological resources, there is limited understanding of the relative importance of different Hg sources and delivery pathways within protected...
Authors
Sarah E. Janssen, Christopher James Kotalik, James Willacker, Michael T. Tate, Colleen M Flanagan-Pritz, Sarah Nelson, David P. Krabbenhoft, David Walters, Collin A. Eagles-Smith
To mix or not to mix: Details of magma storage, recharge, and remobilization during the Pacheco stage at Misti Volcano, Peru (≤21–2 ka) To mix or not to mix: Details of magma storage, recharge, and remobilization during the Pacheco stage at Misti Volcano, Peru (≤21–2 ka)
We investigate ten of the most recent tephra-fall deposits emplaced between ≤21–2 ka from the Pacheco stage of Misti volcano, Peru, to elucidate magma dynamics and explosive eruption triggers related to magma storage, recharge, and remobilization. Whole-rock, glass, and mineral textures and compositions indicate the presence of broadly felsic, intermediate, and mafic magmas in a...
Authors
Marie K. Takach, Frank J. Tepley, Christopher Harpel, Rigoberto Aguilar, Marco Rivera
Greenness and actual evapotranspiration in the unrestored riparian corridor of the Colorado River Delta in response to in-channel water deliveries in 2021 and 2022 Greenness and actual evapotranspiration in the unrestored riparian corridor of the Colorado River Delta in response to in-channel water deliveries in 2021 and 2022
Natural resource managers may utilize remotely sensed data to monitor vegetation within their decision-making frameworks for improving habitats. Under binational agreements between the United States and Mexico, seven reaches were targeted for riparian habitat enhancement. Monitoring was carried out using Landsat 8 16-day intervals of the two-band enhanced vegetation index 2 (EVI2) for...
Authors
Pamela L. Nagler, Ibrahima Sall, Martha Gomez-Sapiens, Armando Barreto-Muñoz, Christopher J. Jarchow, Karl W. Flessa, Kamel Didan
Debris-flow entrainment modelling under climate change: Considering antecedent moisture conditions along the flow path Debris-flow entrainment modelling under climate change: Considering antecedent moisture conditions along the flow path
Debris-flow volumes can increase along their flow path by entraining sediment stored in the channel bed and banks, thus also increasing hazard potential. Theoretical considerations, laboratory experiments and field investigations all indicate that the saturation conditions of the sediment along the flow path can greatly influence the amount of sediment entrained. However, this process is...
Authors
Anna Konz, Jacob Hirschberg, Brian McArdell, Benjamin B. Mirus, Tjalling de Haas, Perry Bartelt, Peter Molnar
Records of fleas (Siphonaptera) from Delaware Records of fleas (Siphonaptera) from Delaware
We present an annotated checklist of fleas (Siphonaptera) known to occur in the state of Delaware based on an examination of Siphonaptera collections at the University of Delaware and the Carnegie Museum of Natural History, as well as new specimens of fleas we collected from wildlife, other hosts, and tick flags. We review published records and compile them herein with our new records...
Authors
A.C Kennedy, W.S. Winter, A.L. Gardner, Neal Woodman, S.A. Shifflett, S. Redus, J.R. Newcomer, R. P. Eckerlin
Restoring blue carbon ecosystems Restoring blue carbon ecosystems
Mangroves, tidal marshes and seagrasses have experienced extensive historical reduction in extent due to direct and indirect effects of anthropogenic land use change. Habitat loss has contributed carbon emissions and led to foregone opportunities for carbon sequestration, which are disproportionately large due to high ‘blue carbon’ stocks and sequestration rates in these coastal...
Authors
Daniel A. Friess, Zoe I. Shribman, Milica Stankovic, Naima Iram, Melissa Millman Baustian, Carolyn J. Ewers Lewis
Evaluation of DNA yield from various tissue and sampling sources for use in single nucleotide polymorphism panels Evaluation of DNA yield from various tissue and sampling sources for use in single nucleotide polymorphism panels
Genetics studies are used by wildlife managers and researchers to gain inference into a population of a species of interest. To gain these insights, microsatellites have been the primary method; however, there currently is a shift from microsatellites to single nucleotide polymorphisms (SNPs). With the different DNA requirements between microsatellites and SNPs, an investigation into...
Authors
David L. Pearce, Jessie E. Edson, Chris S. Jennelle, W. David Walter
Modeling coupled dynamics of an empirical predator-prey system to predict top predator recovery Modeling coupled dynamics of an empirical predator-prey system to predict top predator recovery
Limited data, time, and funding lead conservation managers to make difficult choices in managing species recovery. Coupled dynamical models are relied upon for decision support, but their application to empirical predator-prey systems has generally been restricted to small, tractable species. To broaden their use in conservation decision-making, we developed a model suitable for...
Authors
Samantha N. M. Hamilton, M. T. Tinker, Joseph Jackson, Joseph A. Tomoleoni, Michael C. Kenner, Julie L. Yee, Tomoko Bell, Max C. N. Castorani, Benjamin H. Becker, Brent B. Hughes
Tool use increases mechanical foraging success and tooth health in southern sea otters (Enhydra lutris nereis) Tool use increases mechanical foraging success and tooth health in southern sea otters (Enhydra lutris nereis)
Although tool use may enhance resource utilization, its fitness benefits are difficult to measure. By examining longitudinal data from 196 radio-tagged southern sea otters (Enhydra lutris nereis), we found that tool-using individuals, particularly females, gained access to larger and/or harder-shelled prey. These mechanical advantages translated to reduced tooth damage during food...
Authors
Chris J. Law, M. Tim Tinker, Jessica A. Fujii, Teri Nicholson, Michelle M. Staedler, Joseph A. Tomoleoni, Colleen Young, Rita S. Mehta
Considerations and challenges in support of science and communication of fish consumption advisories for per- and polyfluoroalkyl substances Considerations and challenges in support of science and communication of fish consumption advisories for per- and polyfluoroalkyl substances
Federal, state, tribal, or local entities in the United States issue fish consumption advisories (FCAs) as guidance for safer consumption of locally caught fish containing contaminants. Fish consumption advisories have been developed for commonly detected compounds such as mercury and polychlorinated biphenyls. The existing national guidance does not specifically address the unique...
Authors
Jonathan M. Petali, Erin L. Pulster, Chris McCarthy, Heidi M. Pickard, lsie M. Sunderland, Jacqueline T. Bangma, Anna R. Robuck, Courtney Carignan, Kathryn A. Crawford, Megan E. Romano, Rainer Lohmann, Katherine E. von Stackelberg
Sight and blindness: The relationship between ostracod eyes, water depth, and light availability in the Arctic Ocean Sight and blindness: The relationship between ostracod eyes, water depth, and light availability in the Arctic Ocean
Eye loss has been a long-standing interest in evolutionary biology. Many organisms that inhabit environments without light penetration, for example the deep sea, exhibit eye loss and thus become blind. However, water-depth distribution of eyes in marine organisms is poorly understood. Ostracods are widely distributed crustaceans, and many sighted marine ostracods have eye tubercles...
Authors
Jingwen Zhang, Moriaki Yasuhara, Chih-Lin Wei, Skye Yunshu Tian, Kyawt K. T. Aye, Laura Gemery, Thomas M. Cronin, Peter Frenzel, David J. Horne
On the survival and habitat use of hatchery-reared cisco (Coregonus artedi) in Lake Erie On the survival and habitat use of hatchery-reared cisco (Coregonus artedi) in Lake Erie
Cisco (Coregonus artedi) have been extirpated from Lake Erie in North America since the 1960s, but they once supported one of the largest Laurentian Great Lakes fisheries. Numerous potential impediments to rehabilitation have been identified, including summer habitat refugia and predation. We used acoustic telemetry to investigate the thermal habitat use and survival of hatchery-reared...
Authors
Richard Kraus, James Markham, Jason Robinson, Thomas MacDougall, Matthew Faust, Joseph Schmitt, Christopher Vandergoot, James E. McKenna, Dimitri Gorsky