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The 2016–2017 eruption of Bogoslof primarily produced crystal-rich amphibole basalts. The dominant juvenile tephra were highly microlitic with diktytaxitic vesicles, and amphiboles had large reaction rims. Both observations support a magma history of slow ascent and/or shallow stalling prior to eruption. Plagioclase-amphibole-clinopyroxene mineralogy are also suggestive of shallow magma crystallization....

Spatial and temporal variability characterize submerged aquatic vegetation (SAV) assemblages, but understanding the complex interactions of environmental drivers of SAV assemblages remains elusive. We documented SAV composition and biomass across a salinity gradient in a coastal estuary over 12 mo. Ten macrophyte species were identified. The dominant species, Ceratophyllum demersum and Myriophyllum spicatum, accounted...

Tracking of seabirds has been used to identify foraging hotspots, migratory routes and to assess at-sea threats facing populations. One such threat is the potential negative interaction between seabirds and fisheries through incidental by-catch. In 2012, 60 magnificent frigatebirds Fregata magnificens were found dead, entangled in fishing line,...

Jewel Cave National Monument in the Black Hills of southwestern South Dakota has more than 200 miles of mapped cave passages and several subterranean lakes that have been discovered since 2015. Jewel Cave is one of the world’s longest known caves and its natural beauty and unique natural cave features led...

The city of Sioux Falls, in southeastern South Dakota, is the largest city in South Dakota. The U.S. Geological Survey (USGS), in cooperation with the city of Sioux Falls, completed a groundwater-flow model to use for improving the understanding of groundwater-flow processes, estimating hydrogeologic properties, and analyzing groundwater and surface-water...

Research has traditionally focused on atmospheric release of carbon from thawing permafrost, yet overlooked waterborne release pathways likely contribute significantly, especially in a warming Arctic. To address this knowledge gap and better constrain the fate of carbon in the North, we recommend inter-disciplinary efforts bridging physical, chemical and computational research....

A Decree of the Supreme Court of the United States, entered June 7, 1954, established the position of Delaware River Master within the U.S. Geological Survey. In addition, the Decree authorizes diversion of water from the Delaware River Basin and requires compensating releases from certain reservoirs, owned by New York...

PurposeThe main purpose of this study was to demonstrate the utility of the sediment fingerprinting approach to apportion surface-derived sediment, and then age date that portion using short-lived fallout radionuclides. In systems where a large mass of mobile sediment is in channel storage, age dating provides an understanding...

How carbon cycles are regulated by environmental temperature remains a substantial uncertainty in our understanding of how watersheds will respond to ongoing climate change. Aquatic ecosystems are important components of carbon flux to the atmosphere and ocean, yet we have limited understanding of how temperature modifies ecosystem metabolic processes and,...

The elevated salinity of the Pecos River throughout much of its length is of paramount concern to water users and water managers. Dissolved-solids concentrations in the Pecos River exceed 3,000 milligrams per liter in many of its reaches in the study area, from Santa Rosa Lake, New Mexico, to the...

From 2015 through 2017, the U.S. Geological Survey in cooperation with the New Hampshire Department of Health and Human Services and the New Hampshire Department of Environmental Services studied occurrences of high levels of Escherichia coli (E. coli) bacteria at the Pawtuckaway State Park Beach in Nottingham, New Hampshire. Historic...

Waterfowl and shorebirds are the primary hosts of influenza A virus (IAV), however, in most surveillance efforts, large populations of birds are not routinely examined; specifically marine ducks and other birds that reside predominately on or near the ocean. We conducted a long-term study sampling sea ducks and gulls in...

Drought frequency and intensity are projected to increase throughout the southeastern USA, the natural range of loblolly pine (Pinus taeda L.), and are expected to have major ecological and economic implications. We analyzed the carbon and oxygen isotopic compositions in tree ring cellulose of loblolly pine in a factorial drought...

Repeat sampling and age tracers were used to examine trends in nitrate, arsenic and uranium concentrations in groundwater beneath irrigated cropland. Much higher nitrate concentrations in shallow modern groundwater were observed at both the Columbia Plateau and High Plains sites (median values of 10.2 and 15.4 mg/L as N, respectively)...

Prairie-pothole wetlands provide the critical habitat necessary for supporting North American migratory waterfowl populations. However, climate and land-use change threaten the sustainability of these wetland ecosystems. Very few experiments and analyses have been designed to investigate the relative impacts of climate and land-use change drivers, as well as the antagonistic...

As much as 22 inches of rain fell in Oklahoma in May 2019, resulting in historic flooding along the Arkansas River in Oklahoma and Arkansas. The flooding along the Arkansas River and its tributaries that began in May continued into June 2019. Peaks of record were measured at 12 U.S....

In river channels the flow field influences the dispersion of biota, contaminants, and other suspended or dissolved materials. Insight on patterns and rates of dispersion can be gained by injecting a pulse of visible dye and observing spatial and temporal variations in dye concentration as the pulse moves downstream. We...

Red tree corals (Primnoa pacifica) are abundant in the eastern Gulf of Alaska, from the glacial fjords of Southeast Alaska where they emerge to as shallow as 6 m, to the continental shelf edge and seamounts where they are more commonly found at depths greater than 150 –...

The recent foraminiferal fauna and associated microbiota of Clipperton Island (10.2833°N, 109.2167°W) were investigated at 20 sites collected in the intertidal zone around the perimeter of the island and from the edge of the inner brackish-water lagoon. Due to the island’s geographic location in a low productivity zone, a lack...

A modeling analysis is used to investigate the relative susceptibility of various hydrogeologic configurations to aseismic rupture generation due to deformation of aquifer systems accompanying groundwater pumping. An advanced numerical model (GEPS3D) is used to simulate rupture generation and propagation for three typical processes: (i) reactivation of a preexisting...

Large-scale assessments of rangeland runoff and erosion require methods to extend plot-scale parameterizations to large areas. In this study, Rangeland Hydrology and Erosion Model (RHEM) parameters were developed from plot-scale foliar and ground-cover transect data for an arid, grass-shrub rangeland in southern New Mexico, and a method was assessed to...

The Ouachita Mountains aquifer system potentiometric-surface map is one component of the Hot Springs Bypass Groundwater Monitoring Project. The potentiometric-surface map provides a baseline assessment of shallow groundwater levels and flow directions before the construction of the Arkansas Department of Transportation planned extension of the Highway 270 bypass, east of...

The hyporheic zone, where surface water and groundwater mix, is an important microbial habitat where biogeochemical reactions influence water quality. We show that spatial variability in hyporheic flow in the East River near Crested Butte, Colorado, drives heterogeneity in streambed geochemical conditions and microbial community assemblages, but the diversity of...

The Santa Barbara Area Coastal Ecosystem Vulnerability Assessment (SBA CEVA) is a multidisciplinary research project that investigates future changes to southern Santa Barbara County climate, beaches, watersheds, wetland habitats and beach ecosystems. The target audience is local land use planners and decision makers. The main objective is to provide information that assists the Cities...

This field guide explores volcanic effusions, sediments, and landforms at Mount St. Helens in Washington. A detailed synopsis outlines the eruptive history of Mount St. Helens from about 300,000 years ago through 1980 and beyond.The five days in the field include about 28 stops and 12 potential stops. Exposures in...