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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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Fitting jet noise similarity spectra to volcano infrasound data Fitting jet noise similarity spectra to volcano infrasound data

Infrasound (low-frequency acoustic waves) has proven useful to detect and characterize subaerial volcanic activity, but understanding the infrasonic source during sustained eruptions is still an area of active research. Preliminary comparison between acoustic eruption spectra and the jet noise similarity spectra suggests that volcanoes can produce an infrasonic form of jet noise from...
Authors
Julia Gestrich, David Fee, Robin Matoza, John J. Lyons, Mario Ruiz

Scavengers reduce potential brucellosis transmission risk in the Greater Yellowstone Ecosystem Scavengers reduce potential brucellosis transmission risk in the Greater Yellowstone Ecosystem

Scavengers likely play an important role in ecosystem energy flow as well as disease transmission, but whether they facilitate or reduce disease transmission is often unknown. In the Greater Yellowstone Ecosystem, scavengers are likely to reduce the transmission and subsequent spread of brucellosis within and between livestock and elk by consuming infectious abortion materials, thereby...
Authors
Kimberly E Szcodronski, Paul C. Cross

Predicting regional fluoride concentrations at public and domestic supply depths in basin-fill aquifers of the western United States using a random forest model Predicting regional fluoride concentrations at public and domestic supply depths in basin-fill aquifers of the western United States using a random forest model

A random forest regression (RFR) model was applied to over 12,000 wells with measured fluoride (F) concentrations in untreated groundwater to predict F concentrations at depths used for domestic and public supply in basin-fill aquifers of the western United States. The model relied on twenty-two regional-scale environmental and surficial predictor variables selected to represent factors...
Authors
Celia Z Rosecrans, Kenneth Belitz, Katherine Marie Ransom, Peter B. McMahon, Paul E. Stackelberg

Weakening of peridotite sheared at hydrothermal conditions Weakening of peridotite sheared at hydrothermal conditions

We conducted triaxial friction tests at hydrothermal conditions (25°C–350°C) on gouges of peridotite and its principal mineral constituents olivine and orthopyroxene. Pore-fluid chemistry was varied by the use of peridotite, granite, or quartzite driving blocks (representing wall rock) housing the gouge layer. Samples sheared at slow rates initially strengthen to a peak value, and then...
Authors
Diane E. Moore, David A. Lockner

Comparison of flea sampling methods and Yersinia pestis detection on prairie dog colonies Comparison of flea sampling methods and Yersinia pestis detection on prairie dog colonies

Scientists collect fleas (Siphonaptera) to survey for Yersinia pestis, the bacterial agent of plague. When studying fleas parasitizing prairie dogs (Cynomys spp.), two primary methods are used: (1) combing fleas from live-trapped prairie dogs and (2) swabbing fleas from burrows with cloth swabs attached to metal cables. Ideally, burrow swabbing, the cheaper and easier method, would...
Authors
David A. Eads, Marc R. Matchett, Julia Poje, Dean E. Biggins

Avian community response to a novel environment: Commercial forestry in the Campos grasslands of South America Avian community response to a novel environment: Commercial forestry in the Campos grasslands of South America

Establishing commercial tree plantations in native grassland ecosystems introduces a different structural and functional vegetation cover type, with expected implications for biodiversity. To better understand biodiversity responses to afforestation, we conducted a resource-use study with birds as a focal group, during the 2013–2014 breeding season in the Northern Campos grasslands of...
Authors
J.A. Martinez-Lanfranco, Francisco Vilella, D.A. Miller

Contribution of deep-sourced carbon from hydrocarbon seeps to sedimentary organic carbon: Evidence from radiocarbon and stable isotope geochemistry Contribution of deep-sourced carbon from hydrocarbon seeps to sedimentary organic carbon: Evidence from radiocarbon and stable isotope geochemistry

Sulfate-driven anaerobic oxidation of methane (AOM) limits the release of methane from marine sediments and promotes the formation of carbonates close to the seafloor in seepage areas along continental margins. It has been established that hydrocarbon seeps are a source of methane, dissolved inorganic carbon, and dissolved organic carbon to marine environments. However, questions remain...
Authors
Dong Feng, John Pohlman, Jorn Peckmann, Yuedong Sun, Yu Hu, Harry Roberts, Duofu Chen

Grasslands maintain stability in productivity through compensatory effects and dominant species stability under extreme precipitation patterns Grasslands maintain stability in productivity through compensatory effects and dominant species stability under extreme precipitation patterns

Extreme climatic events are likely to intensify under climate change and can have different effects on ecosystems depending on their timing and magnitude. Understanding how productivity responds to extreme precipitation patterns requires assessing stability and vulnerability during critical growing periods at the plant community level. In this study, we experimentally imposed two...
Authors
Wenlan Gao, Linfeng Li, Seth M. Munson, Xiaoyong Cui, Yanfen Wang, Yanbin Hao

Reproductive plasticity as an advantage of snakes during island invasion Reproductive plasticity as an advantage of snakes during island invasion

Most invasive species are not studied during their initial colonization of ecosystems to which they were recently introduced. Rather, research is typically performed after invasive species are well established and causing harm to the native biodiversity. Thus, novel adaptations of invasive species during their initial invasions are rarely identified. The California kingsnake...
Authors
S R Fisher, Robert N. Fisher, S E Alcaraz, R Gallo-Barneto, C Patino-Martinez, L F Lopez- Jurado, M Á Cabrera-Pérez, J L Grismer

Developing climate resilience in aridlands using rock detention structures as green infrastructure Developing climate resilience in aridlands using rock detention structures as green infrastructure

The potential of ecological restoration and green infrastructure has been long suggested in the literature as adaptation strategies for a changing climate, with an emphasis on revegetation and, more recently, carbon sequestration and stormwater management. Tree planting and “natural” stormwater detention structures such as bioswales, stormwater detention basins, and sediment traps are...
Authors
Laura M. Norman, Benjamin L. Ruddell, Deborah Tosline, Michael Fell, Blair P. Greimann, Jay Cederberg

Rapa Nui (Easter Island) Rano Raraku crater lake basin: Geochemical characterization and implications for the Ahu-Moai Period Rapa Nui (Easter Island) Rano Raraku crater lake basin: Geochemical characterization and implications for the Ahu-Moai Period

Rano Raraku, the crater lake constrained by basaltic tuff that served as the primary quarry used to construct the moai statues on Rapa Nui (Easter Island), has experienced fluctuations in lake level over the past centuries. As one of the only freshwater sources on the island, understanding the present and past geochemical characteristics of the lake water is critical to understand if the...
Authors
Elena Argiriadis, Mara Bortolini, Natalie Kehrwald, Marco Roman, Clara Turetta, Shahpara Hanif, Evans Osayuki Erhendi, Jose Miguel Ramirez Aliaga, David B. McWethy, Amy E. Myrbo, Anibal Pauchard, Carlo Barbante, Dario Battistel

A new approach to evaluate and reduce uncertainty of model-based biodiversity projections for conservation policy formulation A new approach to evaluate and reduce uncertainty of model-based biodiversity projections for conservation policy formulation

Biodiversity projections with uncertainty estimates under different climate, land-use, and policy scenarios are essential to setting and achieving international targets to mitigate biodiversity loss. Evaluating and improving biodiversity predictions to better inform policy decisions remains a central conservation goal and challenge. A comprehensive strategy to evaluate and reduce...
Authors
Bonnie Myers, Sarah R. Weiskopf, Alexey N. Shiklomanov, Simon Ferrier, Ensheng Weng, Kimberly Ann Casey, Michael Harfoot, Stephen Jackson, Allison K. Leidner, Timothy M. Lenton, Gordon Luikart, Hiroyuki Matsuda, Nathalie Pettorelli, Isabel M. D. Rosa, Alexander C. Ruane, Gabriel B. Senay, Shawn P. Serbin, Derek P. Tittensor, Beard
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