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Suspended-sediment concentration data were collected by the U.S. Geological Survey in San Francisco Bay during water year 2010 (October 1, 2009–September 30, 2010). Turbidity sensors and water samples were used to monitor suspended-sediment concentration at two sites in Suisun Bay, one site in San Pablo Bay, three sites in Central...

Downhole wireline log (DWL) data was acquired from eight drill sites during China's first gas hydrate drilling expedition (GMGS-1) in 2007. Initial analyses of the acquired well log data suggested that there were no significant gas hydrate occurrences at Site SH4. However, the re-examination of the DWL data from Site...

The Gulf of Mexico annual summer hypoxia forecasts are based on average May total nitrogen loads from the Mississippi River basin for that year. The load estimate, recently released by USGS, is 4,761 metric tons per day. Based on that estimate, we predict the area of this summer’s hypoxic zone...

The English chemistry pioneer Sir Humphry Davy first combined gas and water to produce a solid substance in his lab in 1810. For more than a century after that landmark moment, a small number of scientists catalogued various solid “hydrates” formed by combining water with an assortment of gases and...

New U-Pb igneous and detrital zircon ages reveal that despite being separated by younger orogens, three of Alaska’s terranes that contain Precambrian rocks—Farewell, Kilbuck, and Arctic Alaska—are related. The Farewell and Kilbuck terranes can be linked by felsic magmatism at ca. 850 Ma and by abundant detrital zircons in the...

Shell beads appear to have been one of the earliest examples of personal adornments. Marine shells identified far from the shore evidence long-distance transport and imply networks of exchange and negotiation. However, worked beads lose taxonomic clues to identification, and this may be compounded by taphonomic alteration. Consequently, the significance...

40Ar/39Ar geochronology depends critically on well-calibrated standards, often traceable to first-principles K-Ar age calibrations using bulb-tracer systems. Tracer systems also provide precise standards for noble-gas studies and interlaboratory calibration. The exponential expression long used for calculating isotope tracer concentrations in K-Ar age dating and calibration of 40Ar/39Ar age standards may...

A stratigraphic synthesis of dozens of deep-sea cores, most of them overlooked in recent decades, provides new insights into deep-sea turbidites as guides to earthquake and tsunami hazards along the Cascadia subduction zone, which extends 1100 km along the Pacific coast of North America. The synthesis shows greater variability in...

Great earthquakes anticipated on the Cascadia subduction fault can potentially rupture beyond the geodetically and thermally inferred locked zone to the depths of episodic tremor and slip (ETS) or to the even deeper fore-arc mantle corner (FMC). To evaluate these extreme rupture limits, we map the FMC from southern Vancouver...

Ground shaking due to earthquakes in the eastern United States (EUS) is felt at significantly greater distances than in the western United States (WUS) and for some earthquakes it has been shown to display a strong preferential direction. Shaking intensity variation can be due to propagation path effects, source directivity,...

Tidal wetlands are some of the most dynamic areas of the Earth and are found at the interface between the land and sea. Salinity, regular tidal flooding, and infrequent catastrophic flooding due to storm events result in complex interactions among biotic and abiotic factors. The complexity of these interactions, along...

Conserving genetic diversity and local adaptations are management priorities for wild populations of exploited species, which increasingly are subject to climate change, habitat loss, and pollution. These constitute growing concerns for the walleye Sander vitreus, an ecologically and economically valuable North American temperate fish with large...

Aquatic vegetation provides food resources and shelter for many species of fish. This study found a significant relationship between increases in submersed aquatic vegetation (SAV) in four study reaches of the Upper Mississippi River (UMR) and increases in catch-per-unit-effort (CPUE) of weed shiners (Notropis texanus) and age-0 bluegills...

Onondaga Creek begins approximately 15 miles south of Syracuse, New York, and flows north through the Onondaga Indian Nation, then through Syracuse, and finally into Onondaga Lake in central New York. Tully Valley is in the upper part of the Onondaga Creek watershed between U.S. Route 20 and the Valley...

A tenet of earthquake science is that faults are locked in position until they abruptly slip during the sudden strain-relieving events that are earthquakes. Whereas it is expected that locked faults when they finally do slip will produce noticeable ground shaking, what is uncertain is how the ground shakes during...

Atrazine is an effective broadleaf herbicide and the second most heavily used herbicide in the United States. Effects along the hypothalamus–pituitary–gonad axis in a number of vertebrate taxa have been demonstrated. Seasonally elevated concentrations of atrazine in surface waters may adversely affect fishes, but only a few studies have examined...

Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse,...

Samples of three high volatile bituminous coals were subjected to parallel sets of extractions involving solvents dichloromethane (DCM), carbon disulfide (CS2), and supercritical carbon dioxide (CO2) (40 °C, 100 bar) to study processes affecting coal–solvent interactions. Recoveries of perdeuterated surrogate compounds, n-hexadecane-d34 and four polycyclic aromatic hydrocarbons (PAHs), added as...

Ecosystems dominated by big sagebrush, Artemisia tridentata Nuttall (Asteraceae), which are the most widespread ecosystems in semiarid western North America, have been affected by land use practices and invasive species. Loss of big sagebrush and the decline of associated species, such as greater sage-grouse, are a concern to land managers...

Recent studies have shown that excessive dissolved-solids concentrations in water can have adverse effects on the environment and on agricultural, domestic, municipal, and industrial water users. Such effects motivated the U.S. Geological Survey’s National Water Quality Assessment Program to develop a SPAtially-Referenced Regression on Watershed Attributes (SPARROW) model that has...

Trace metals, such as arsenic, iron, lead, manganese, and uranium, in groundwater used for drinking have long been a concern because of the potential adverse effects on human health and the aesthetic or nuisance problems that some present. Moderate to high concentrations of the trace metal arsenic have been identified...

Citizen science projects, which engage non-professional scientists in one or more stages of scientific research, have been gaining popularity; yet maintaining participants’ activity level over time remains a challenge. The objective of this study was to evaluate the potential for a short-term, focused campaign to increase participant activity in a...

We measured total selenium and total mercury concentrations ([TSe] and [THg]) in hair (n = 138) and blood (n = 73) of harbor seals (Phoca vitulina) from California to assess variation by geography and sex, and inferred feeding relationships based on carbon, nitrogen, and sulfur stable isotopes. Harbor seals from...

The health of Largescale Sucker (Catostomus macrocheilus) in the lower Columbia River (USA) was evaluated using morphometric and histopathological approaches, and its association with organic contaminants accumulated in liver was evaluated in males. Fish were sampled from three sites along a contaminant gradient In 2009, body length and mass, condition...

The current state of science and engineering related to analyzing wetlands overlooks the importance of transpiration and risks data misinterpretation. In response, we developed hydrologic and mass budgets for agricultural wetlands using electrical conductivity (EC) as a natural conservative tracer. We developed simple differential equations that quantify evaporation and transpiration...