Hydroacoustic measures of Mysis relicta abundance and distribution in Lake Ontario
L. G. Rudstam, T. Schaner, G. Gal, B. T. Boscarino, R. O'Gorman, D.M. Warner, O. E. Johannsson, K.L. Bowen
2008, Conference Paper, Aquatic Ecosystem Health and Management
Mysis relicta can be observed on echograms as a sound scattering layer when they migrate into the water column at night to feed on zooplankton. However, quantitative measures of mysid abundance with hydroacoustics requires knowledge of mysid target strength (TS), a method of removing fish echoes and contribution from noise,...
A morphological review of the Cuora flavomarginata complex (Testudines: Geoemydidae)
C.H. Ernst, A.F. Laemmerzahl, J.E. Lovich
2008, Proceedings of the Biological Society of Washington (121) 391-397
A reevaluation of the morphometric and color pattern differences within the Asiatic box turtle, Cuora flavomarginata sensu latu, was conducted in view of determining the taxonomic position of the three currently recognized subspecies: C. f. flavomarginata (Taiwan), C. f. sinensis (southern mainland China), and C. f. evelynae (Ryukyu Islands, Japan)....
Size of spawning population, residence time, and territory shifts of individuals in the spawning aggregation of a riverine catostomid
T.B. Grabowski, J. Jeffery Isely
2008, Southeastern Naturalist (7) 475-482
Little is known about the behavior of individual fish in a spawning aggregation, specifically how long an individual remains in an aggregation. We monitored Moxostoma robustum (Cope) (Robust Redhorse) in a Savannah River spawning aggregation during spring 2004 and 2005 to provide an estimate of the total number of adults...
Application of environmental groundwater tracers at the Sulphur Bank Mercury Mine, California, USA
M.A. Engle, F. Goff, D.G. Jewett, G.J. Reller, J.B. Bauman
2008, Hydrogeology Journal (16) 559-573
Boron, chloride, sulfate, ??D, ??18O, and 3H concentrations in surface water and groundwater samples from the Sulphur Bank Mercury Mine (SBMM), California, USA were used to examine geochemical processes and provide constraints on evaporation and groundwater flow. SBMM is an abandoned sulfur and mercury mine with an underlying hydrothermal system,...
Nutrient dynamics as indicators of karst processes: Comparison of the Chalk aquifer (Normandy, France) and the Edwards aquifer (Texas, U.S.A.)
B.J. Mahler, D. Valdes, M. Musgrove, N. Massei
2008, Journal of Contaminant Hydrology (98) 36-49
Karst aquifers display a range of geologic and geomorphic characteristics in a wide range of climatic and land-use settings; identification of transport dynamics representative of karst aquifers in general could help advance our understanding of these complex systems. To this end, nutrient, turbidity, and major ion dynamics in response to...
Space-based detection of wetlands' surface water level changes from L-band SAR interferometry
S. Wdowinski, S.-W. Kim, F. Amelung, T.H. Dixon, F. Miralles-Wilhelm, R. Sonenshein
2008, Remote Sensing of Environment (112) 681-696
Interferometric processing of JERS-1 L-band Synthetic Aperture Radar (SAR) data acquired over south Florida during 1993-1996 reveals detectable surface changes in the Everglades wetlands. Although our study is limited to south Florida it has implication for other large-scale wetlands, because south Florida wetlands have diverse vegetation types and both managed...
Planning riparian restoration in the context of tamarix control in Western North America
P.B. Shafroth, Vanessa B. Beauchamp, M.K. Briggs, K. Lair, M. L. Scott, A.A. Sher
2008, Restoration Ecology (16) 97-112
Throughout the world, the condition of many riparian ecosystems has declined due to numerous factors, including encroachment of non-native species. In the western United States, millions of dollars are spent annually to control invasions of Tamarix spp., introduced small trees or shrubs from Eurasia that have colonized bottomland ecosystems along...
A test of the cross-scale resilience model: Functional richness in Mediterranean-climate ecosystems
D.A. Wardwell, Craig R. Allen, G.D. Peterson, A.J. Tyre
2008, Ecological Complexity (5) 165-182
Ecological resilience has been proposed to be generated, in part, in the discontinuous structure of complex systems. Environmental discontinuities are reflected in discontinuous, aggregated animal body mass distributions. Diversity of functional groups within body mass aggregations (scales) and redundancy of functional groups across body mass aggregations (scales) has been proposed...
Physical and chemical changes in the foreshore of an estuarine beach: Implications for viability and development of horseshoe crab Limulus polyphemus eggs
N.L. Jackson, D. R. Smith, K.F. Nordstrom
2008, Marine Ecology Progress Series (355) 209-218
Knowledge of conditions that favor development of eggs is important for management of species whose population growth is sensitive to early life history survival. Viability and development of the eggs of horseshoe crabs Limulus polyphemus on a sand and gravel beach were evaluated using data gathered on Delaware Bay, USA,...
Influences of the unsaturated, saturated, and riparian zones on the transport of nitrate near the Merced River, California, USA
Joseph L. Domagalski, S.P. Phillips, E.R. Bayless, C. Zamora, C. Kendall, R.A. Wildman, J. G. Hering
2008, Hydrogeology Journal (16) 675-690
Transport and transformation of nitrate was evaluated along a 1-km groundwater transect from an almond orchard to the Merced River, California, USA, within an irrigated agricultural setting. As indicated by measurements of pore-water nitrate and modeling using the root zone water quality model, about 63% of the applied nitrogen was...
Influence of natural dissolved organic carbon on the bioavailability of mercury to a freshwater alga
P.R. Gorski, D.E. Armstrong, J.P. Hurley, D. P. Krabbenhoft
2008, Environmental Pollution (154) 116-123
Bioavailability of mercury (Hg) to Selenastrum capricornutum was assessed in bioassays containing field-collected freshwater of varying dissolved organic carbon (DOC) concentrations. Bioconcentration factor (BCF) was measured using stable isotopes of methylmercury (MeHg) and inorganic Hg(II). BCFs for MeHg in low-DOC lake water were significantly larger than those in mixtures of...
Anthropogenic influences on the input and biogeochemical cycling of nutrients and mercury in Great Salt Lake, Utah, USA
D. Naftz, C. Angeroth, T. Kenney, B. Waddell, N. Darnall, S. Silva, C. Perschon, J. Whitehead
2008, Applied Geochemistry (23) 1731-1744
Despite the ecological and economic importance of Great Salt Lake (GSL), little is known about the input and biogeochemical cycling of nutrients and trace elements in the lake. In response to increasing public concern regarding anthropogenic inputs to the GSL ecosystem, the US Geological Survey (USGS) and US Fish and...
Validation of daily ring deposition in the otoliths of age-0 channel catfish
P.C. Sakaris, E.R. Irwin
2008, North American Journal of Fisheries Management (28) 212-218
We developed and validated methods for estimating the daily age of age-0 channel catfish Ictalurus punctatus. Two clutches of channel catfish eggs were hatched in the laboratory; subsequently, one was stocked in a 186-m2 earthen nursery pond and the other in a 757-L outdoor circular tank. Before stocking, subsamples of...
Effectiveness of household reverse-osmosis systems in a Western U.S. region with high arsenic in groundwater
M. Walker, R. L. Seiler, M. Meinert
2008, Science of the Total Environment (389) 245-252
It is well known to the public in Lahontan Valley in rural Nevada, USA, that local aquifers produce water with varied, but sometimes very high concentrations of arsenic (> 4??ppm). As a result, many residents of the area have installed household reverse-osmosis (RO) systems to produce drinking water. We examined...
Reconstructed historical land cover and biophysical parameters for studies of land-atmosphere interactions within the eastern United States
Louis T. Steyaert, R.G. Knox
2008, Journal of Geophysical Research D: Atmospheres (113) 1-27
Over the past 350 years, the eastern half of the United States experienced extensive land cover changes. These began with land clearing in the 1600s, continued with widespread deforestation, wetland drainage, and intensive land use by 1920, and then evolved to the present-day landscape of forest regrowth, intensive agriculture, urban...
Map scale effects on estimating the number of undiscovered mineral deposits
D.A. Singer, W. D. Menzie
2008, Natural Resources Research (17) 79-86
Estimates of numbers of undiscovered mineral deposits, fundamental to assessing mineral resources, are affected by map scale. Where consistently defined deposits of a particular type are estimated, spatial and frequency distributions of deposits are linked in that some frequency distributions can be generated by processes randomly in space whereas others...
Variation in maternal effects and embryonic development rates among passerine species
T. E. Martin, H. Schwabl
2008, Philosophical Transactions of the Royal Society B: Biological Sciences (363) 1663-1674
Embryonic development rates are reflected by the length of incubation period in birds, and these vary substantially among species within and among geographical regions. The incubation periods are consistently shorter in North America (Arizona study site) than in tropical (Venezuela) and subtropical (Argentina) South America based on the study of...
Tile drainage as karst: Conduit flow and diffuse flow in a tile-drained watershed
K. E. Schilling, M. Helmers
2008, Journal of Hydrology (349) 291-301
The similarity of tiled-drained watersheds to karst drainage basins can be used to improve understanding of watershed-scale nutrient losses from subsurface tile drainage networks. In this study, short-term variations in discharge and chemistry were examined from a tile outlet collecting subsurface tile flow from a 963 ha agricultural watershed. Study...
Extent of the last ice sheet in northern Scotland tested with cosmogenic 10Be exposure ages
W.M. Phillips, A.M. Hall, C.K. Ballantyne, S. Binnie, P.W. Kubik, S. Freeman
2008, Journal of Quaternary Science (23) 101-107
The extent of the last British-Irish Ice Sheet (BIIS) in northern Scotland is disputed. A restricted ice sheet model holds that at the global Last Glacial Maximum (LGM; ca. 23-19 ka) the BIIS terminated on land in northern Scotland, leaving Buchan, Caithness and the Orkney Islands ice-free. An alternative model...
Comparison of pesticide concentrations in streams at low flow in six metropolitan areas of the United States
Lori A. Sprague, Lisa H. Nowell
2008, Environmental Toxicology and Chemistry (27) 288-298
To examine the effect of urban development on pesticide concentrations in streams under low-flow conditions, water samples were collected at stream sites along an urban land use gradient in six environmentally heterogeneous metropolitan areas of the United States. In all six metropolitan areas, total insecticide concentrations generally increased significantly as...
Defoliation effects on Bromus tectorum seed production: Implications for grazing
K. Hempy-Mayer, D.A. Pyke
2008, Rangeland Ecology and Management (61) 116-123
Cheatgrass (Bromus tectorum L.) is an invasive annual grass that creates near-homogenous stands in areas throughout the Intermountain sagebrush steppe and challenges successful native plant restoration in these areas. A clipping experiment carried out at two cheatgrass-dominated sites in eastern Oregon (Lincoln Bench and Succor Creek) evaluated defoliation as a...
Evaluation of statistical treatments of left-censored environmental data using coincident uncensored data sets: I. Summary statistics
Ronald C. Antweiler, Howard E. Taylor
2008, Environmental Science & Technology (42) 3732-3738
The main classes of statistical treatment of below-detection limit (left-censored) environmental data for the determination of basic statistics that have been used in the literature are substitution methods, maximum likelihood, regression on order statistics (ROS), and nonparametric techniques. These treatments, along with using all instrument-generated data (even those below detection),...
Shallow water processes govern system-wide phytoplankton bloom dynamics: A field study
J.K. Thompson, Jeffrey R. Koseff, Stephen G. Monismith, L.V. Lucas
2008, Journal of Marine Systems (74) 153-166
Prior studies of the phytoplankton dynamics in South San Francisco Bay, California, USA have hypothesized that bivalve filter-feeders are responsible for the limited phytoplankton blooms in the system. This study was designed to examine the effects of benthic grazing and light attenuation on this shallow, turbid, and nutrient replete system....
Effects of acclimation on the toxicity of stream water contaminated with zinc and cadmium to juvenile cutthroat trout
D.D. Harper, A.M. Farag, W. G. Brumbaugh
2008, Archives of Environmental Contamination and Toxicology (54) 697-704
We investigated the influence of acclimation on results of in situ bioassays with cutthroat trout in metal-contaminated streams. Cutthroat trout (Oncorhynchus clarki) were held for 21 days (1) in live containers at a reference or "clean" site having dissolved metals near detection limits (0.01 ??g/L cadmium [Cd] and 2.8 ??g/L...
Detection of foliage-obscured vehicle using a multiwavelength polarimetric lidar
S. Tan, J. Stoker, S. Greenlee
2008, Conference Paper, International Geoscience and Remote Sensing Symposium (IGARSS)
Foliage obscured man-made targets detection and identification is of great interest to many applications. In this paper, the backscattered laser signals from a multiwavelength polarimetric lidar were used to detect a vehicle hidden inside a vegetated area. The polarimetric reflectance data from the lidar at two separate laser wavelengths at...
