Mapping of accumulated nitrogen in the sediment pore water of a eutrophic lake in Iowa, USA
M.Z. Iqbal, C.L. Fields
2009, Environmental Geology (57) 465-475
A large pool of nitrogen in the sediment pore fluid of a eutrophic lake in Iowa, USA, was mapped in this study. Previously, the lake had supported fishing and boating, but today it no longer supports its designated uses as a recreational water body. In the top 5 cm of...
Two statistics for evaluating parameter identifiability and error reduction
John Doherty, Randall J. Hunt
2009, Journal of Hydrology (366) 119-127
Two statistics are presented that can be used to rank input parameters utilized by a model in terms of their relative identifiability based on a given or possible future calibration dataset. Identifiability is defined here as the capability of model calibration to constrain parameters used by a model. Both statistics...
Extreme endurance flights by landbirds crossing the Pacific Ocean: Ecological corridor rather than barrier?
Robert E. Gill Jr., T. Lee Tibbitts, David C. Douglas, Colleen M. Handel, Daniel M. Mulcahy, Jon C. Gottschalck, Nils Warnock, Brian J. McCaffery, Phil F. Battley, Theunis Piersma
2009, Proceedings of the Royal Society B: Biological Sciences (276) 447-457
Mountain ranges, deserts, ice fields and oceans generally act as barriers to the movement of land-dependent animals, often profoundly shaping migration routes. We used satellite telemetry to track the southward flights of bar-tailed godwits (Limosa lapponica baueri), shorebirds whose breeding and non-breeding areas are separated by the vast central Pacific...
Late Pleistocene to Holocene sedimentation and hydrocarbon seeps on the continental shelf of a steep, tectonically active margin, southern California, USA
Amy E. Draut, Patrick E. Hart, T.D. Lorenson, Holly F. Ryan, Florence L. Wong, Ray W. Sliter, James E. Conrad
2009, Marine Geophysical Research (30) 193-206
Small, steep, uplifting coastal watersheds are prolific sediment producers that contribute significantly to the global marine sediment budget. This study illustrates how sedimentation evolves in one such system where the continental shelf is largely sediment-starved, with most terrestrial sediment bypassing the shelf in favor of deposition in deeper basins. The...
Shallow water processes govern system-wide phytoplankton bloom dynamics: A modeling study
L.V. Lucas, Jeffrey R. Koseff, Stephen G. Monismith, J.K. Thompson
2009, Journal of Marine Systems (75) 70-86
A pseudo-two-dimensional numerical model of estuarine phytoplankton growth and consumption, vertical turbulent mixing, and idealized cross-estuary transport was developed and applied to South San Francisco Bay. This estuary has two bathymetrically distinct habitat types (deep channel, shallow shoal) and associated differences in local net rates of phytoplankton growth and consumption,...
VP Structure of Mount St. Helens, Washington, USA, imaged with local earthquake tomography
G.P. Waite, S.C. Moran
2009, Journal of Volcanology and Geothermal Research (182) 113-122
We present a new P-wave velocity model for Mount St. Helens using local earthquake data recorded by the Pacific Northwest Seismograph Stations and Cascades Volcano Observatory since the 18 May 1980 eruption. These data were augmented with records from a dense array of 19 temporary stations deployed during the second...
Interactive effects of fire, soil climate, and moss on CO2 fluxes in black spruce ecosystems of interior Alaska
Jonathan A. O’Donnell, Merritt R. Turetsky, Jennifer W. Harden, Kristen L. Manies, L.E. Pruett, Gordon Shetler, Jason C. Neff
2009, Ecosystems (12) 57-72
Fire is an important control on the carbon (C) balance of the boreal forest region. Here, we present findings from two complementary studies that examine how fire modifies soil organic matter properties, and how these modifications influence rates of decomposition and C exchange in black spruce (Picea mariana)...
Histopathology of repeated, intermittent exposure of chloramine-T to walleye (Sander vitreum) and (Ictalurus punctalus) channel catfish
M.P. Gaikowski, Christine L. Densmore, V. S. Blazer
2009, Aquaculture (287) 28-34
Chloramine-T (Cl-T) has been used safely and effectively to control bacterial gill disease in salmonids at a maximum exposure regimen of up to four consecutive, once-daily exposures administered for 60??min at 20??mg/L. However, data to document safe treatment concentrations of Cl-T are lacking for freshwater-reared fish other than salmonids. We...
What parts of the US mainland are climatically suitable for invasive alien pythons spreading from Everglades National Park?
G.H. Rodda, C. S. Jarnevich, R.N. Reed
2009, Biological Invasions (11) 241-252
The Burmese Python (Python molurus bivittatus) is now well established in southern Florida and spreading northward. The factors likely to limit this spread are unknown, but presumably include climate or are correlated with climate. We compiled monthly rainfall and temperature statistics from 149 stations located near the edge of the...
Ecological impacts of lead mining on Ozark streams: Toxicity of sediment and pore water
J.M. Besser, W. G. Brumbaugh, A.L. Allert, B.C. Poulton, C. J. Schmitt, C.G. Ingersoll
2009, Ecotoxicology and Environmental Safety (72) 516-526
We studied the toxicity of sediments downstream of lead-zinc mining areas in southeast Missouri, using chronic sediment toxicity tests with the amphipod, Hyalella azteca, and pore-water toxicity tests with the daphnid, Ceriodaphnia dubia. Tests conducted in 2002 documented reduced survival of amphipods in stream sediments collected near mining areas and...
A cross-site comparison of factors influencing soil nitrification rates in northeastern USA forested watersheds
D.S. Ross, B.C. Wemple, A.E. Jamison, G. Fredriksen, J. B. Shanley, G.B. Lawrence, S.W. Bailey, J.L. Campbell
2009, Ecosystems (12) 158-178
Elevated N deposition is continuing on many forested landscapes around the world and our understanding of ecosystem response is incomplete. Soil processes, especially nitrification, are critical. Many studies of soil N transformations have focused on identifying relationships within a single watershed but these results are often not transferable. We studied...
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...
Geology and geochemistry of the Mammoth breccia pipe, Copper Creek mining district, southeastern Arizona: Evidence for a magmatic-hydrothermal origin
E. D. Anderson, William W. Atkinson Jr., T. Marsh, A. Iriondo
2009, Mineralium Deposita (44) 151-170
The Copper Creek mining district, southeastern Arizona, contains more than 500 mineralized breccia pipes, buried porphyry-style, copper-bearing stockworks, and distal lead-silver veins. The breccia pipes are hosted by the Copper Creek Granodiorite and the Glory Hole volcanic rocks. The unexposed Mammoth breccia pipe, solely recognized by drilling, has a vertical...
Hurricane Rita and the destruction of Holly Beach, Louisiana: Why the chenier plain is vulnerable to storms
Asbury H. Sallenger Jr., C. W. Wright, Kara Doran, K. Guy, Karen Morgan
2009, Special Paper of the Geological Society of America (460) 127-135
Hurricane Rita devastated gulf-front communities along the western Louisiana coast in 2005. LIDAR (light detection and ranging) topographic surveys and aerial photography collected before and after the storm showed the loss of every structure within the community of Holly Beach. Average shoreline change along western Louisiana's 140-km-long impacted shore was...
Sulfur geochemistry of hydrothermal waters in Yellowstone National Park: IV Acid-sulfate waters
D. Kirk Nordstrom, R. Blaine McCleskey, J.W. Ball
2009, Applied Geochemistry (24) 191-207
Many waters sampled in Yellowstone National Park, both high-temperature (30-94 ??C) and low-temperature (0-30 ??C), are acid-sulfate type with pH values of 1-5. Sulfuric acid is the dominant component, especially as pH values decrease below 3, and it forms from the oxidation of elemental S whose origin is H2S in...
Landscape planning for agricultural nonpoint source pollution reduction III: Assessing phosphorus and sediment reduction potential
M.W. Diebel, J.T. Maxted, Dale M. Robertson, S. Han, M. J. Vander Zanden
2009, Environmental Management (43) 69-83
Riparian buffers have the potential to improve stream water quality in agricultural landscapes. This potential may vary in response to landscape characteristics such as soils, topography, land use, and human activities, including legacies of historical land management. We built a predictive model to estimate the sediment and phosphorus load reduction...
Seasonal movements and Home-range use by female pronghorns in sagebrush-steppe communities of western South Dakota
C.N. Jacques, J.A. Jenks, R. W. Klaver
2009, Journal of Mammalogy (90) 433-441
Knowledge of seasonal movements by pronghorns (Antilocapra americana) within the easternmost extension of sagebrush-steppe communities is limited. Current hypotheses regarding movement patterns suggest that pronghorns initiate seasonal movements in response to severe winter weather, snowfall patterns, spatial and temporal variation in forage abundance, and availability of water. From January 2002...
A prelanding assessment of the ice table depth and ground ice characteristics in Martian permafrost at the Phoenix landing site
Michael T. Mellon, William V. Boynton, William C. Feldman, Raymond E. Arvidson, Timothy N. Titus, Joshua L. Bandfield, Nathaniel E. Putzig, H.G. Sizemore
2009, Journal of Geophysical Research E: Planets (114)
We review multiple estimates of the ice table depth at potential Phoenix landing sites and consider the possible state and distribution of subsurface ice. A two-layer model of ice-rich material overlain by ice-free material is consistent with both the observational and theoretical lines of evidence. Results indicate ground ice to...
The unexpected awakening of Chaitén Volcano, Chile
Simon A. Carn, John S. Zogorski, Luis Lara, John W. Ewert, Sebastian Watt, Alfred J. Prata, Ronald J. Thomas, Gustavo Villarosa
2009, Eos, Transactions, American Geophysical Union (90) 205-206
On 2 May 2008, a large eruption began unexpectedly at the inconspicuous Chaitén volcano in Chile's southern volcanic zone. Ash columns abruptly jetted from the volcano into the stratosphere, followed by lava dome effusion and continuous low-altitude ash plumes [Lara, 2009]. Apocalyptic photographs of eruption plumes suffused with...
Transport of viruses through saturated and unsaturated columns packed with sand
R. Anders, C.V. Chrysikopoulos
2009, Transport in Porous Media (76) 121-138
Laboratory-scale virus transport experiments were conducted in columns packed with sand under saturated and unsaturated conditions. The viruses employed were the male-specific RNA coliphage, MS2, and the Salmonella typhimurium phage, PRD1. The mathematical model developed by Sim and Chrysikopoulos (Water Resour Res 36:173–179, 2000) that accounts for processes responsible for...
Geochemical gradients in soil O-horizon samples from southern Norway: Natural or anthropogenic?
C. Reimann, P. Englmaier, B. Flem, L. Gough, P. Lamothe, O. Nordgulen, D. Smith
2009, Applied Geochemistry (24) 62-76
Forty soil O- and C-horizon samples were collected along a south-to-north transect extending inland for approximately 200 km from the southern tip of Norway. The elements As, Au, Bi, Cd, Cu, Ga, Ge, Hf, Hg, In, Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, V, W, Zn and Zr all...
Directed site exploration for permeable reactive barrier design
J. Lee, A.J. Graettinger, J. Moylan, H. W. Reeves
2009, Journal of Hazardous Materials (162) 222-229
Permeable reactive barriers (PRBs) are being employed for in situ site remediation of groundwater that is typically flowing under natural gradients. Site characterization is of critical importance to the success of a PRB. A design-specific site exploration approach called quantitatively directed exploration (QDE) is presented. The QDE approach employs three...
Low-velocity zone and topography as a source of site amplification effect on Tarzana hill, California
V. Graizer
2009, Soil Dynamics and Earthquake Engineering (29) 324-332
Tarzana station is located in the foothills of the Santa Monica Mountains in California near the crest of a low (<20 m) natural hill with gentle slopes. The hill is about 500 m in length by 130 m in width and is formed of extremely weathered shale at the surface...
Hydrograph separation for karst watersheds using a two-domain rainfall-discharge model
Andrew J. Long
2009, Journal of Hydrology (364) 249-256
Highly parameterized, physically based models may be no more effective at simulating the relations between rainfall and outflow from karst watersheds than are simpler models. Here an antecedent rainfall and convolution model was used to separate a karst watershed hydrograph into two outflow components: one originating from focused recharge in...
Phenologically-tuned MODIS NDVI-based production anomaly estimates for Zimbabwe
Chris Funk, Michael E. Budde
2009, Remote Sensing of Environment (113) 115-125
For thirty years, simple crop water balance models have been used by the early warning community to monitor agricultural drought. These models estimate and accumulate actual crop evapotranspiration, evaluating environmental conditions based on crop water requirements. Unlike seasonal rainfall totals, these models take into account the phenology of the crop,...
