Coastal circulation and water-column properties in the National Park of American Samoa, February–July 2015
Curt D. Storlazzi, Olivia Cheriton, Kurt J. Rosenberger, Joshua B. Logan, Timothy B. Clark
2017, Open-File Report 2017-1060
There is little information on the oceanography in the National Park of American Samoa (NPSA). The transport pathways for potentially harmful constituents of land-derived runoff, as well as larvae and other planktonic organisms, are driven by nearshore circulation patterns. To evaluate the processes affecting coral reef ecosystem health, it is...
Using a gradient in food quality to infer drivers of fatty acid content in two filter-feeding aquatic consumers
James H. Larson, William B. Richardson, Jonathan M. Vallazza, Lynn A. Bartsch, Michelle R. Bartsch
2017, Aquatic Sciences (79) 855-865
Inferences about ecological structure and function are often made using elemental or macromolecular tracers of food web structure. For example, inferences about food chain length are often made using stable isotope ratios of top predators and consumer food sources are often inferred from both stable isotopes and fatty acid (FA)...
Regional and temporal variability of melts during a Cordilleran magma pulse: Age and chemical evolution of the jurassic arc, eastern mojave desert, California
A.P. Barth, J.L. Wooden, David M. Miller, Keith A. Howard, Lydia Fox, Elizabeth R. Schermer, C.E. Jacobson
2017, Geological Society of America Bulletin (129) 429-448
Intrusive rock sequences in the central and eastern Mojave Desert segment of the Jurassic Cordilleran arc of the western United States record regional and temporal variations in magmas generated during the second prominent pulse of Mesozoic continental arc magmatism. U/Pb zircon ages provide temporal control for describing variations in rock...
Nutrient feedbacks to soil heterotrophic nitrogen fixation in forests
Steven S. Perakis, Julie C. Pett-Ridge, Christina E. Catricala
2017, Biogeochemistry (134) 41-55
Multiple nutrient cycles regulate biological nitrogen (N) fixation in forests, yet long-term feedbacks between N-fixation and coupled element cycles remain largely unexplored. We examined soil nutrients and heterotrophic N-fixation across a gradient of 24 temperate conifer forests shaped by legacies of symbiotic N-fixing trees. We observed positive relationships among mineral...
Variability of dissolved organic carbon in precipitation during storms at the Shale Hills Critical Zone Observatory
Lidiia Iavorivska, Elizabeth W. Boyer, Jeffrey W. Grimm, Matthew P. Miller, David R. DeWalle, Kenneth J. Davis, Margot W. Kaye
2017, Hydrological Processes (31) 2935-2950
Organic compounds are removed from the atmosphere and deposited to the earth's surface via precipitation. In this study, we quantified variations of dissolved organic carbon (DOC) in precipitation during storm events at the Shale Hills Critical Zone Observatory, a forested watershed in central Pennsylvania (USA). Precipitation samples were collected consecutively...
Intraspecific variability and reaction norms of forest understory plant species traits
Julia I. Burton, Steven S. Perakis, Sean C. McKenzie, Caitlin E. Lawrence, Klaus J. Puettmann
2017, Functional Ecology (31) 1881-1893
Trait-based models of ecological communities typically assume intraspecific variation in functional traits is not important, though such variation can change species trait rankings along gradients in resources and environmental conditions, and thus influence community structure and function.We examined the degree of intraspecific relative to interspecific variation, and reaction norms of...
How misapplication of the hydrologic unit framework diminishes the meaning of watersheds
James M. Omernik, Glenn E. Griffith, Robert M. Hughes, James B. Glover, Marc H. Weber
2017, Environmental Management (60) 1-11
Hydrologic units provide a convenient but problematic nationwide set of geographic polygons based on subjectively determined subdivisions of land surface areas at several hierarchical levels. The problem is that it is impossible to map watersheds, basins, or catchments of relatively equal size and cover the whole country. The hydrologic unit...
Spatio-temporal mapping of plate boundary faults in California using geodetic imaging
Andrea Donnellan, Ramon Arrowsmith, Stephen B. DeLong
2017, Geosciences (7) 1-26
The Pacific–North American plate boundary in California is composed of a 400-km-wide network of faults and zones of distributed deformation. Earthquakes, even large ones, can occur along individual or combinations of faults within the larger plate boundary system. While research often focuses on the primary and secondary faults, holistic study...
Application of an unstructured 3D finite volume numerical model to flows and salinity dynamics in the San Francisco Bay-Delta
R.C. Martyr-Koller, H.W.J. Kernkamp, Anne A. Van Dam, Mick van der Wegen, Lisa Lucas, N. Knowles, B. Jaffe, T.A. Fregoso
2017, Estuarine, Coastal and Shelf Science (192) 86-107
A linked modeling approach has been undertaken to understand the impacts of climate and infrastructure on aquatic ecology and water quality in the San Francisco Bay-Delta region. The Delft3D Flexible Mesh modeling suite is used in this effort for its 3D hydrodynamics, salinity, temperature and sediment dynamics, phytoplankton and...
Demographic consequences of nest box use for Red-footed Falcons Falco vespertinus in Central Asia
Evgeny A. Bragin, Alexander E. Bragin, Todd E. Katzner
2017, Ibis (159) 841-853
Nest box programs are frequently implemented for the conservation of cavity-nesting birds, but their effectiveness is rarely evaluated in comparison to birds not using nest boxes. In the European Palearctic, Red-footed Falcon Falco vespertinus populations are both of high conservation concern and are strongly associated with nest box programs in...
Using high-throughput DNA sequencing, genetic fingerprinting, and quantitative PCR as tools for monitoring bloom-forming and toxigenic cyanobacteria in Upper Klamath Lake, Oregon, 2013 and 2014
Sara L. Caldwell Eldridge, Conner Driscoll, Theo W. Dreher
2017, Scientific Investigations Report 2017-5026
Monitoring the community structure and metabolic activities of cyanobacterial blooms in Upper Klamath Lake, Oregon, is critical to lake management because these blooms degrade water quality and produce toxic microcystins that are harmful to humans, domestic animals, and wildlife. Genetic tools, such as DNA fingerprinting by terminal restriction fragment...
USGS integrated drought science
Andrea C. Ostroff, Clint C. Muhlfeld, Patrick M. Lambert, Nathaniel L. Booth, Shawn L. Carter, Jason M. Stoker, Michael J. Focazio
2017, Circular 1430
Project Need and OverviewDrought poses a serious threat to the resilience of human communities and ecosystems in the United States (Easterling and others, 2000). Over the past several years, many regions have experienced extreme drought conditions, fueled by prolonged periods of reduced precipitation and exceptionally warm temperatures. Extreme drought has...
Indicator-driven conservation planning across terrestrial, freshwater aquatic, and marine ecosystems of the south Atlantic, USA
Bradley A. Pickens, Rua S. Mordecai, C. Ashton Drew, Louise B. Alexander-Vaughn, Amy S. Keister, Hilary L.C. Morris, Jaime A. Collazo
2017, Journal of Fish and Wildlife Management (8) 219-233
Systematic conservation planning, a widely used approach to identify priority lands and waters, uses efficient, defensible, and transparent methods aimed at conserving biodiversity and ecological systems. Limited financial resources and competing land uses can be major impediments to conservation; therefore, participation of diverse stakeholders in the planning process is advantageous...
Snow and ice
Jeremy S. Littell, Stephanie A. McAfee, Shad O’Neel, Louis C. Sass, Evan Burgess, Steve Colt, Paul Clark
Gregory D. Hayward, Steve Colt, Monica L. McTeague, Teresa N. Hollingsworth, editor(s)
2017, General Technical Report PNW-GTR-950-3
Temperature and precipitation are key determinants of snowpack levels. Therefore, climate change is likely to affect the role of snow and ice in the landscapes and hydrology of the Chugach National Forest region.Downscaled climate projections developed by Scenarios Network for Alaska and Arctic Planning (SNAP) are useful for examining projected...
Amphibian terrestrial habitat selection and movement patterns vary with annual life-history period
Luke A. Groff, Aram J.K. Calhoun, Cynthia S. Loftin
2017, Canadian Journal of Zoology (95) 433-442
Identification of essential habitat is a fundamental component of amphibian conservation; however, species with complex life histories frequently move among habitats. To better understand dynamic habitat use, we evaluated Wood Frog (Lithobates sylvaticus (LeConte, 1825)) habitat selection and movement patterns during the spring migration and foraging periods and described the spatiotemporal...
Mapping climate change refugia in the Sierra Nevada
Toni Lyn Morelli
2017, Newsletter
No abstract available....
Magnetic monitoring in Saguaro National Park
Jeffrey J. Love, Carol Finn, Yesenia C. Gamez Valdez, Don Swann
2017, Fact Sheet 2017-3035
On a sandy, arid plain, near the Rincon Mountain Visitor Center of Saguaro National Park, tucked in among brittlebush, creosote, and other hardy desert plants, is an unusual type of observatory—a small unmanned station that is used for monitoring the Earth’s variable magnetic field. Named for the nearby city of...
Evaluation of long-term trends in hydrologic and water-quality conditions, and estimation of water budgets through 2013, Chester County, Pennsylvania
Ronald A. Sloto, Andrew G. Reif
2017, Scientific Investigations Report 2017-5025
An evaluation of trends in hydrologic and water quality conditions and estimation of water budgets through 2013 was done by the U.S. Geological Survey in cooperation with the Chester County Water Resources Authority. Long-term hydrologic, meteorologic, and biologic data collected in Chester County, Pennsylvania, which included streamflow, groundwater levels, surface-water...
Incorporating genetic sampling in long-term monitoring and adaptive management in the San Diego County Management Strategic Plan Area, Southern California
Amy G. Vandergast
2017, Open-File Report 2017-1061
Habitat and species conservation plans usually rely on monitoring to assess progress towards conservation goals. Southern California, USA, is a hotspot of biodiversity and home to many federally endangered and threatened species. Here, several regional multi-species conservation plans have been implemented to balance development and conservation goals, including in...
Methane and benzene in drinking-water wells overlying the Eagle Ford, Fayetteville, and Haynesville Shale hydrocarbon production areas
Peter B. McMahon, Jeannie R. B. Barlow, Mark A. Engle, Kenneth Belitz, Patricia B. Ging, Andrew G. Hunt, Bryant C. Jurgens, Yousif K. Kharaka, Roland W. Tollett, Timothy M. Kresse
2017, Environmental Science & Technology (51) 6727-6734
Water wells (n = 116) overlying the Eagle Ford, Fayetteville, and Haynesville Shale hydrocarbon production areas were sampled for chemical, isotopic, and groundwater-age tracers to investigate the occurrence and sources of selected hydrocarbons in groundwater. Methane isotopes and hydrocarbon gas compositions indicate most of the methane in the wells was...
Monitoring the cooling of the 1959 Kīlauea Iki lava lake using surface magnetic measurements
Lydie Gailler, James P. Kauahikaua
2017, Bulletin of Volcanology (79) 1-7
Lava lakes can be considered as proxies for small magma chambers, offering a unique opportunity to investigate magma evolution and solidification. Repeated magnetic ground surveys over more than 50 years each show a large vertical magnetic intensity anomaly associated with Kīlauea Iki Crater, partly filled with a lava lake during the...
A shifting rift—Geophysical insights into the evolution of Rio Grande rift margins and the Embudo transfer zone near Taos, New Mexico
V. J. S. Grauch, Paul W. Bauer, Benjamin J. Drenth, Keith I. Kelson
2017, Geosphere (13) 870-910
We present a detailed example of how a subbasin develops adjacent to a transfer zone in the Rio Grande rift. The Embudo transfer zone in the Rio Grande rift is considered one of the classic examples and has been used as the inspiration for several theoretical models. Despite this...
Seasonal and spatial variabilities in northern Gulf of Alaska surface water iron concentrations driven by shelf sediment resuspension, glacial meltwater, a Yakutat eddy, and dust
John Crusius, Andrew W. Schroth, Joseph A. Resing, Jay Cullen, Robert W. Campbell
2017, Global Biogeochemical Cycles (31) 942-960
Phytoplankton growth in the Gulf of Alaska (GoA) is limited by iron (Fe), yet Fe sources are poorly constrained. We examine the temporal and spatial distributions of Fe, and its sources in the GoA, based on data from three cruises carried out in 2010 from the Copper River (AK) mouth...
Thermal and petrologic constraints on lower crustal melt accumulation under the Salton Sea Geothermal Field
Ozge Karakas, Josef Dufek, Margaret T. Mangan, Heather M. Wright, Olivier Bachmann
2017, Earth and Planetary Science Letters (467) 10-17
In the Salton Sea region of southern California (USA), concurrent magmatism, extension, subsidence, and sedimentation over the past 0.5 to 1.0 Ma have led to the creation of the Salton Sea Geothermal Field (SSGF)—the second largest and hottest geothermal system in the continental United States—and the small-volume rhyolite eruptions that...
Sediment source fingerprinting as an aid to catchment management: A review of the current state of knowledge and a methodological decision-tree for end-users
A.L Collins, S. Pulley, I.D.L Foster, Allen C. Gellis, P. Porto, A.J. Horowitz
2017, Journal of Environmental Management (194) 86-108
The growing awareness of the environmental significance of fine-grained sediment fluxes through catchment systems continues to underscore the need for reliable information on the principal sources of this material. Source estimates are difficult to obtain using traditional monitoring techniques, but sediment source fingerprinting or tracing procedures, have emerged as a...
