Numerical models of caldera deformation: Effects of multiphase and multicomponent hydrothermal fluid flow
M. Hutnak, S. Hurwitz, S. E. Ingebritsen, P. A. Hsieh
2009, Journal of Geophysical Research B: Solid Earth (114)
Ground surface displacement (GSD) in large calderas is often interpreted as resulting from magma intrusion at depth. Recent advances in geodetic measurements of GSD, notably interferometric synthetic aperture radar, reveal complex and multifaceted deformation patterns that often require complex source models to explain the observed GSD. Although hydrothermal fluids have...
Rapid measurement of field-saturated hydraulic conductivity for areal characterization
J. R. Nimmo, K. M. Schmidt, K. S. Perkins, J. D. Stock
2009, Vadose Zone Journal (8) 142-149
To provide an improved methodology for characterizing the field‐saturated hydraulic conductivity (Kfs) over broad areas with extreme spatial variability and ordinary limitations of time and resources, we developed and tested a simplified apparatus and procedure, correcting mathematically for the major deficiencies of the simplified implementation. The methodology includes use of...
Distribution and postbreeding environmental relationships of Northern leopard frogs (Rana [Lithobates] pipiens) in Washington
S.S. Germaine, D.W. Hays
2009, Western North American Naturalist (69) 537-547
Northern leopard frogs (Rana [Lithobates] pipiens) are considered sensitive, threatened, or endangered in all western states and western Canadian provinces. Historically present in eastern Washington in 6 major river drainages, leopard frogs are now only known to occur at 2 localized areas in the Crab Creek drainage in Grant County....
In situ video observations of two manefishes (perciformes: Caristiidae) in the mesopelagic zone of the northern Gulf of Mexico
M.C. Benfield, John H. Caruso, K. J. Sulak
2009, Copeia (4) 637-641
This paper describes direct video observations of two manefishes, likely Paracaristius sp., from the mesopelagic waters of the north-central Gulf of Mexico. One fish was observed with a remotely operated vehicle at a depth of 829 m by an industrial ROV as part of the SERPENT Project. The second was...
Recent increases in the large glacial-relict calanoid Limnocalanus macrurus in Lake Michigan
R.P. Barbiero, D.B. Bunnell, D.C. Rockwell, M.L. Tuchman
2009, Journal of Great Lakes Research (35) 285-292
Since 2004, population density of the large hypolimnetic calanoid Limnocalanus macrurus Sars. has increased dramatically in Lake Michigan. The average summer biomass of this species between 2004 and 2006 was roughly three times that of the period 1984–2003, and at levels unprecedented in our 22-year dataset, making L. macrurus the...
Groundwater's significance to changing hydrology, water chemistry, and biological communities of a floodplain ecosystem, Everglades, South Florida, USA
J. W. Harvey, P.V. McCormick
2009, Hydrogeology Journal (17) 185-201
The Everglades (Florida, USA) is one of the world's larger subtropical peatlands with biological communities adapted to waters low in total dissolved solids and nutrients. Detecting how the pre-drainage hydrological system has been altered is crucial to preserving its functional attributes. However, reliable tools for hindcasting historic conditions in the...
Influence of small impoundments on habitat and fish communities in headwater streams
M.T. Kashiwagi, L.E. Miranda
2009, Southeastern Naturalist (8) 23-36
We surveyed the habitat and fish assemblages of four impounded and three unimpounded neighboring headwater streams, separated longitudinally into multiple upstream and downstream reaches. Instream habitat characteristics were similar between reaches of unimpounded streams and reaches above impoundments, and differed significantly from reaches below impoundments that included deeper water and...
Benthic biogeochemical cycling, nutrient stoichiometry, and carbon and nitrogen mass balances in a eutrophic freshwater bay
J.V. Klump, S.A. Fitzgerald, J.T. Waplesa
2009, Limnology and Oceanography (54) 692-712
Green Bay, while representing only ~7% of the surface area and ~1.4% of the volume of Lake Michigan, contains one‐third of the watershed of the lake, and receives approximately one‐third of the total nutrient loading to the Lake Michigan basin, largely from the Fox River at the southern end of...
Estimating nitrogen loading to ground water and assessing vulnerability to nitrate contamination in a large karstic springs Basin, Florida
B. G. Katz, A.A. Sepulveda, R.J. Verdi
2009, Journal of the American Water Resources Association (45) 607-627
A nitrogen (N) mass-balance budget was developed to assess the sources of N affecting increasing ground-water nitrate concentrations in the 960-km 2 karstic Ichetucknee Springs basin. This budget included direct measurements of N species in rainfall, ground water, and spring waters, along with estimates of N loading from fertilizers, septic...
Seed dispersal and seedling emergence in a created and a natural salt marsh on the Gulf of Mexico coast in Southwest Louisiana, U.S.A
T. Elsey-Quirk, B.A. Middleton, C.E. Proffitt
2009, Restoration Ecology (17) 422-432
Early regeneration dynamics related to seed dispersal and seedling emergence can contribute to differences in species composition among a created and a natural salt marsh. The objectives of this study were to determine (1) whether aquatic and aerial seed dispersal differed in low and high elevations within a created marsh...
Rates and trends of coastal change in california and the regional behavior of the beach and cliff system
C.J. Hapke, Don Reid, B. Richmond
2009, Journal of Coastal Research (25) 603-615
The U.S. Geological Survey (USGS) recently completed an analysis of shoreline change and cliff retreat along the California coast. This is the first regional, systematic measurement of coastal change conducted for the West Coast. Long-term (-120 y) and short-term (-25 y) shoreline change rates were calculated for more than 750...
How useful are the "other" semipermeable membrane devices (SPMDs); the mini-unit (15.2 cm long)?
Steven L. Goodbred, Wade L. Bryant Jr., Michael R. Rosen, David Alvarez, Terri Spencer
2009, Science of the Total Environment (407) 4149-4156
Mini (15.2 cm) semipermeable membrane devices (SPMDs) were used successfully in 169 streams from six metropolitan areas of the US to sequester hydrophobic organic compounds (HOCs) that are indicative of urbanization. A microscale assay the P450RGS, which responds to compounds that bind to the aryl hydrocarbon receptor (AhR), and the Fluoroscan,...
Scaling the effects of moose browsing on forage distribution, from the geometry of plant canopies to landscapes
N. R. De Jager, J. Pastor, A.L. Hodgson
2009, Ecological Monographs (79) 281-297
Landscape heterogeneity influences large herbivores by altering their feeding rates, but as herbivores attempt to maximize feeding rates they also create spatial heterogeneity by altering plant growth. Herbivore feeding rates thus provide a quantitative link between the causes and consequences of spatial heterogeneity in herbivore-dominated ecosystems. The fractal geometry of...
Sediment regime constraints on river restoration - An example from the lower Missouri river
R. B. Jacobson, D. W. Blevins, C.J. Bitner
2009, Special Paper of the Geological Society of America (451) 1-22
Dammed rivers are subject to changes in their flow, water-quality, and sediment regimes. Each of these changes may contribute to diminished aquatic habitat quality and quantity. Of the three factors, an altered sediment regime is a particularly unyielding challenge on many dammed rivers. The magnitude of the challenge is illustrated...
Coastal ocean transport patterns in the central Southern California Bight
M.A. Noble, K.J. Rosenberger, P. Hamilton, J. P. Xu
2009, Special Paper of the Geological Society of America 193-226
In the past decade, several large programs that monitor currents and transport patterns for periods from a few months to a few years were conducted by a consortium of university, federal, state, and municipal agencies in the central Southern California Bight, a heavily urbanized section of the coastal ocean off...
Carbon cycling under 300 years of land use change: importance of the secondary vegetation sink
Elena Shevliakova, Stephen W. Pacala, Sergey Malyshev, George C. Hurtt, P. C. D. Milly, John P. Caspersen, Lori T. Sentman, Justin P. Fisk, Christian Wirth, Cyril Crevoisier
2009, Global Biogeochemical Cycles (23)
We have developed a dynamic land model (LM3V) able to simulate ecosystem dynamics and exchanges of water, energy, and CO2 between land and atmosphere. LM3V is specifically designed to address the consequences of land use and land management changes including cropland and pasture dynamics, shifting cultivation, logging, fire, and resulting...
Water velocity and the nature of critical flow in large rapids on the Colorado River, Utah
Christopher S. Magirl, Jeffrey W. Gartner, Graeme M. Smart, Robert H. Webb
2009, Water Resources Research (45)
Rapids are an integral part of bedrock‐controlled rivers, influencing aquatic ecology, geomorphology, and recreational value. Flow measurements in rapids and high‐gradient rivers are uncommon because of technical difficulties associated with positioning and operating sufficiently robust instruments. In the current study, detailed velocity, water surface, and bathymetric data were collected within...
Web-based decision support and visualization tools for water quality management in the Chesapeake Bay watershed
C. Mullinix, P. Hearn, H. Zhang, J. Aguinaldo
2009, Conference Paper, 2009 17th International Conference on Geoinformatics, Geoinformatics 2009
Federal, State, and local water quality managers charged with restoring the Chesapeake Bay ecosystem require tools to maximize the impact of their limited resources. To address this need, the U.S. Geological Survey (USGS) and the Environmental Protection Agency's Chesapeake Bay Program (CBP) are developing a suite of Web-based tools called...
Water balance dynamics in the Nile Basin
Gabriel B. Senay, Kwabena Asante, Guleid A. Artan
2009, Hydrological Processes (23) 3675-3681
Understanding the temporal and spatial dynamics of key water balance components of the Nile River will provide important information for the management of its water resources. This study used satellite-derived rainfall and other key weather variables derived from the Global Data Assimilation System to estimate and map the distribution of...
Dispersal of river sediment in the Southern California Bight
J.A. Warrick, K.L. Farnsworth
2009, Special Paper of the Geological Society of America 53-67
The rivers of Southern California deliver episodic pulses of water, sediment, nutrients, and pollutants to the region's coastal waters. Although river-sediment dispersal is observed in positively buoyant (hypopycnal) turbid plumes extending tens of kilometers from river mouths, very little of the river sediment is found in these plumes. Rather, river...
Variations of thiaminase I activity pH dependencies among typical Great Lakes forage fish and Paenibacillus thiaminolyticus.
J.L. Zajicek, L. Brown, S.B. Brown, D. C. Honeyfield, J.D. Fitzsimons, D. E. Tillitt
2009, Journal of Aquatic Animal Health (21) 207-216
The source of thiaminase in the Great Lakes food web remains unknown. Biochemical characterization of the thiaminase I activities observed in forage fish was undertaken to provide insights into potential thiaminase sources and to optimize catalytic assay conditions. We measured the thiaminase I activities of crude extracts from five forage...
Geologic columns for the ICDP-USGS Eyreville A and C cores, Chesapeake Bay impact structure: Postimpact sediments, 444 to 0 m depth
Lucy E. Edwards, David S. Powars, J.V. Browning, P.P. McLaughlin Jr., K.G. Miller, Self-Trail J.M., A.A. Kulpecz, T. Elbra
2009, Special Paper of the Geological Society of America 91-114
A 443.9-m-thick, virtually undisturbed section of postimpact deposits in the Chesapeake Bay impact structure was recovered in the Eyreville A and C cores, Northampton County, Virginia, within the "moat" of the structure's central crater. Recovered sediments are mainly fine-grained marine siliciclastics, with the exception of Pleistocene sand, clay, and gravel....
Geologic columns for the ICDP-USGS Eyreville A and B cores, Chesapeake Bay impact structure: Sediment-clast breccias, 1096 to 444 m depth
Lucy E. Edwards, David S. Powars, Gregory Gohn, H. Dypvik
2009, Special Paper of the Geological Society of America 51-89
The Eyreville A and B cores, recovered from the “moat” of the Chesapeake Bay impact structure, provide a thick section of sediment-clast breccias and minor stratified sediments from 1095.74 to 443.90 m. This paper discusses the...
Timing and petroleum sources for the Lower Cretaceous Mannville Group oil sands of northern Alberta based on 4-D modeling
D.K. Higley, M. D. Lewan, L. N. R. Roberts, M. Henry
2009, American Association of Petroleum Geologists Bulletin (93) 203-230
The Lower Cretaceous Mannville Group oil sands of northern Alberta have an estimated 270.3 billion m3 (BCM) (1700 billion bbl) of in-place heavy oil and tar. Our study area includes oil sand accumulations and downdip areas that partially extend into the deformation zone in western Alberta. The oil sands are...
Trends in concentrations and use of agricultural herbicides for Corn Belt rivers, 1996-2006
Aldo V. Vecchia, Robert J. Gilliom, Daniel J. Sullivan, David L. Lorenz, Jeffrey D. Martin
2009, Environmental Science & Technology (43) 9096-9102
Trends in the concentrations and agricultural use of four herbicides (atrazine, acetochlor, metolachlor, and alachlor) were evaluated for major rivers of the Corn Belt for two partially overlapping time periods: 1996-2002 and 2000-2006. Trends were analyzed for 11 sites on the mainstems and selected tributaries in the Ohio, Upper Mississippi,...
