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The volcanic aquifers of the Hawaiian Islands supply water to 1.46 million residents, diverse industries, and a large component of the U.S. military in the Pacific. Groundwater also supplies fresh water that supports ecosystems in streams and near the coast. Hawaii’s aquifers are remarkably productive given their small size, but...

Fire regimes in sagebrush (Artemisia spp.) ecosystems have been greatly altered across the western United States. Broad-scale invasion of non-native annual grasses, climate change, and human activities have accelerated wildfire cycles, increased fire size and severity, and lengthened fire seasons in many sagebrush ecosystems...

Amaranthus pumilus (seabeach amaranth) is a federally threatened plant species that has been the focus of restoration efforts at Assateague Island National Seashore (ASIS). Despite several years with strong population numbers prior to 2010, monitoring efforts have revealed a significant decline in the seabeach amaranth population since that time, the...

Integrating tracking technology and molecular approaches provides a comprehensive picture of contemporary and evolutionary mechanisms promoting connectivity. We used mitochondrial DNA and double digest restriction-site associated DNA (ddRAD) sequencing combined with satellite telemetry to investigate the connectivity of geographically disparate breeding populations of a declining boreal shorebird, the lesser yellowlegs...

Host range and specificity are key concepts in the study of infectious diseases. However, both concepts remain largely undefined for many influential pathogens, including many fungi within the Onygenales order. This order encompasses reptile-infecting genera (Nannizziopsis, Ophidiomyces, and Paranannizziopsis) formerly classified as the Chrysosporium anamorph of Nannizziopsis vriesii (CANV). The reported hosts of many of these...

Alviso Slough in South San Francisco Bay has been experiencing restoration of adjacent former salt-production ponds into muted tidal ponds, tidal ponds, and salt marsh. As a result, tidal prism through Alviso Slough has increased and mercury-contaminated sediment has been remobilized. We developed...

For millennia, Inuit peoples of the Arctic and Subarctic have been challenged by the impacts of climate change on the abundance of key subsistence species. Responses to climate-induced declines in animal populations included switching to alternative food sources and/or migrating to regions of greater availability. We examine these dynamics...

Remote aerial sensing provides a non-invasive, large geographical-scale technology for avian monitoring, but the manual processing of images limits its development and applications. Artificial Intelligence (AI) methods can be used to mitigate this manual image processing requirement. The implementation of AI methods, however, has several...

In the Great Lakes region, thiamine deficiency is considered a recruitment bottleneck for lake trout Salvelinus namaycush and has been correlated with the consumption of non-native alewife Alosa pseudoharengus. While alewife, the most abundant forage fish in Lake Ontario, are the predominant prey for lake trout, they...

Colorado Pikeminnow Ptychocheilus lucius, the Colorado River’s top native predatory fish, was historically distributed from the Gulf of California delta to the upper reaches of the Green, Colorado, and San Juan rivers in the Colorado River basin in the Southwestern US. In recent...

Reservoirs in arid landscapes provide critical water storage and hydroelectric power but influence the transport and biogeochemical cycling of mercury (Hg). Improved management of reservoirs to mitigate the supply and uptake of bioavailable methylmercury (MeHg) in aquatic food webs will benefit from a mechanistic understanding of inorganic divalent Hg...

Reactive nitrogen (Nr) concentrations are higher than expected for mountain lakes in Rocky Mountain National Park, and for many years, high Nr concentrations have been attributed to atmospheric Nr deposition from regional and more distant emission sources, including combustion of fossil fuels and agricultural...

The shallower portions of subduction zone megathrust faults host Earth’s most hazardous tsunamigenic earthquakes, yet understanding how and when they slip remains elusive because of challenges making seafloor observations. We performed Global Navigation Satellite System Acoustic seafloor geodetic surveys before and ~2.5 months after the 29 July 2021 Mw (moment magnitude) 8.2...

Executive SummaryChromium concentrations in rock and aquifer material in Hinkley and Water Valleys in the Mojave Desert, 80 miles northeast of Los Angeles, California, are generally low compared to the average chromium concentration of 185 milligrams per kilogram (mg/kg) in the average bulk continental crust. Chromium concentrations in felsic, coarse-textured...

Groundwater containing hexavalent chromium, Cr(VI), downgradient from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert, 80 miles northeast of Los Angeles, California, is undergoing bioremediation using added ethanol as a reductant in a volume of the aquifer defined as the in situ reactive zone...

Hydrologic and geophysical data were collected to support updates to an existing groundwater-flow model of Hinkley Valley, California, in the Mojave Desert about 80 miles northeast of Los Angeles, California. These data provide information on predevelopment (pre-1930) water levels, groundwater recharge, and selected hydrologic properties of aquifer materials.A predevelopment groundwater-level...

Hexavalent chromium, Cr(VI), was released between 1952 and 1964 from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station, in the Mojave Desert about 80 miles northeast of Los Angeles, California. Geologic, geochemical, and hydrologic data from more than 100 wells collected between March 2015 and November 2017 were...

Hexavalent chromium, Cr(VI), was discharged in cooling wastewater to unlined surface ponds from 1952 to 1964 and reached the underlying unconsolidated aquifer at the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert, 80 miles northeast of Los Angeles, California. A suite of environmental tracers was...

Water samples collected by the U.S. Geological Survey from more than 100 wells between March 2015 and November 2017 in Hinkley and Water Valleys, in the Mojave Desert 80 miles northeast of Los Angeles, California, were analyzed for field parameters, major ions, nutrients, and selected trace elements, including hexavalent chromium,...

Between 1952 and 1964, hexavalent chromium, Cr(VI), was released into groundwater from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert 80 miles northeast of Los Angeles, California. The Pacific Gas and Electric Company has monitored groundwater near Hinkley, California, for Cr(VI) and other constituents...

Between 1952 and 1964, hexavalent chromium, Cr(VI), was released into groundwater from a Pacific Gas and Electric Company (PG&E) compressor station in Hinkley, California, in the western Mojave Desert 80 miles northeast of Los Angeles, California. In 2015, the extent of anthropogenic Cr(VI) in groundwater in Hinkley and Water Valleys...

Between 1952 and 1964, hexavalent chromium, Cr(VI), was released into groundwater from the Pacific Gas and Electric Company (PG&E) compressor station in Hinkley, California, in the western Mojave Desert 80 miles northeast of Los Angeles, California. In 2015, the extent of anthropogenic Cr(VI) in groundwater in Hinkley and Water Valleys...

Between 1952 and 1964, hexavalent chromium, Cr(VI), was released into groundwater from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert 80 miles (mi) northeast of Los Angeles, California. Remediation began in 1992, and in 2010, site cleanup was projected to require between 10 and...

Between 1952 and 1964, hexavalent chromium, Cr(VI), was released into groundwater from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert 80 miles (mi) northeast of Los Angeles, California. Remediation began in 1992, and in 2010, site cleanup was projected to require between 10...

During the Late Pleistocene, major parts of North America were periodically covered by ice sheets. However, there are still questions about whether ice-free refugia were present in the Alexander Archipelago along the Southeast (SE) Alaska coast during the last glacial maximum (LGM). Numerous subfossils have been recovered from caves in...