Skip to main content

Organization

Office of the Chief Operating Officer

Office of the Chief Operating Officer
thumbnail
Long-term monitoring of stream-bed sediments reveals spatial and temporal trends in metal concentrations. Here we use concentration gradient “heat maps” as a visualization tool to report annual mean arsenic, cadmium and copper concentrations along a contamination gradient in the Clark Fork River (CFR) in Western Montana. The CFR has been heavily impacted by large-scale mining operations since the 19th century. Legacy mine waste and tailings have been deposited within the streambed, banks, and floodplains more than 200 kilometers downstream. Sieved sediment samples (<63µm) have been collected at 10 stations along a 200 kilometer contamination gradient annually since 1996. Ongoing remediation activities in the upper...
thumbnail
Estuaries provide critical habitat for a vast array of fish and wildlife but are also a nexus for core economic activities that mobilize and concentrate contaminants that can threaten aquatic species. Selenium (Se), an essential element and potent reproductive toxin, is enriched in parts of the San Francisco Estuary (SFE) to levels known to cause toxicity, yet the risk of Se to species that inhabit the SFE is not well understood. We quantified Se concentrations in muscle, liver, and ovary of the demersal cyprinid Sacramento Splittail from six regions in the SFE at three time points (fall 2010-11, spring 2017) to evaluate Se exposure risk. Here we report fish morphological attributes, total selenium concentrations...
thumbnail
Declining phytoplankton biomass and the resulting stress on the food web has been suggested as one contributor to the decline of Delta Smelt and other fish species in the San Francisco Bay (SFB) and the Sacramento San Joaquin River Delta. Filter feeding by two species of bivalves, Corbicula fluminea and Potamocorbula amurensis, has been shown to control phytoplankton growth rate in the SFB and Delta and both are thought to be partially responsible for the reduction in food for pelagic species. Phytoplankton growth rate is dependent on spatially and temporally varying nutrient concentrations, light availability, transport time, and pelagic and benthic grazing losses. Bivalve grazing has the potential to limit primary...
thumbnail
The U.S. Geological Survey in collaboration with the U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL) collected topographic LiDAR surveys of six rivers in Alaska from August 27-September 1, 2018 to support research related to remote sensing of river discharge. Data were acquired for the Knik, Matanuska, Chena, Salcha, Tanana and Snow Rivers using a Riegl VQ-480 LiDAR. The LiDAR was installed on a Robinson R44 Raven helicopter in a HeliPod that was designed and operated by CRREL. The LiDAR data included as part of this release include: a bare earth digital elevation model (DEM) in GeoTiff format, and compressed binary LAS files (LAZ) for each river surveyed.
thumbnail
Evaluating technologies and approaches to detect the infiltration of fines into coarser materials has implications for monitoring the condition of habitat restoration sites. This goal motivated testing the efficacy of Fiber Optic Distributed Temperature Sensing (FO-DTS) as a technique for detecting the infiltration of fine sediment into gravels. Experiments were conducted in a laboratory flume at the USGS Geomorphology and Sediment Transport Laboratory (GSTL) in Golden, Colorado. A 10 meter fiber optic cable was placed in the flume with one half of the cable buried approximately 6 centimeters in a substrate (gravel, sand, and mixtures of the two) along the length of the flume, while the other half was placed at...
View more...
ScienceBase brings together the best information it can find about USGS researchers and offices to show connections to publications, projects, and data. We are still working to improve this process and information is by no means complete. If you don't see everything you know is associated with you, a colleague, or your office, please be patient while we work to connect the dots. Feel free to contact sciencebase@usgs.gov.