Diurnal variability in riverine dissolved organic matter composition determined by in situ optical measurement in the San Joaquin River (California, USA)
R.G.M. Spencer, B.A. Pellerin, B.A. Bergamaschi, B.D. Downing, T.E.C. Kraus, D.R. Smart, R.A. Dahlgren, P.J. Hernes
2007, Hydrological Processes (21) 3181-3189
Dissolved organic matter (DOM) concentration and composition in riverine and stream systems are known to vary with hydrological and productivity cycles over the annual and interannual time scales. Rivers are commonly perceived as homogeneous with respect to DOM concentration and composition, particularly under steady flow conditions over short time periods....
Amplitude loss of sonic waveform due to source coupling to the medium
Myung W. Lee, William F. Waite
2007, Geophysical Research Letters (34)
In contrast to hydrate-free sediments, sonic waveforms acquired in gas hydrate-bearing sediments indicate strong amplitude attenuation associated with a sonic velocity increase. The amplitude attenuation increase has been used to quantify pore-space hydrate content by attributing observed attenuation to the hydrate-bearing sediment's intrinsic attenuation. A second attenuation mechanism must be...
Use of eyeballs for establishing ploidy of Asian carp
J.A. Jenkins, R.G. Thomas
2007, North American Journal of Fisheries Management (27) 1195-1202
Grass carp Ctenopharyngodon idella, silver carp Hypophthalmichthys molitrix, and bighead carp H. nobilis are now established and relatively common in the Mississippi and Atchafalaya rivers. Commercial fishers of Louisiana's large rivers report recurrent catches of grass carp, and the frequency of bighead carp and silver carp catch is increasing. Twelve...
Cross-calibration of the Terra MODIS, Landsat 7 ETM+ and EO-1 ALI sensors using near-simultaneous surface observation over the Railroad Valley Playa, Nevada, test site
G. Chander, A. Angal, T. Choi, D. J. Meyer, X. Xiong, P.M. Teillet
2007, Conference Paper
A cross-calibration methodology has been developed using coincident image pairs from the Terra Moderate Resolution Imaging Spectroradiometer (MODIS), the Landsat 7 (L7) Enhanced Thematic Mapper Plus (ETM+) and the Earth Observing EO-1 Advanced Land Imager (ALI) to verify the absolute radiometric calibration accuracy of these sensors with respect to each...
Detection ratios on winter surveys of Rocky Mountain Trumpeter Swans Cygnus buccinator
J. Bart, C.D. Mitchell, M.N. Fisher, J.A. Dubovsky
2007, Wildfowl (57) 21-28
We estimated the detection ratio for Rocky Mountain Trumpeter Swans Cygnus buccinator that were counted during aerial surveys made in winter. The standard survey involved counting white or grey birds on snow and ice and thus might be expected to have had low detection ratios. On the other hand, observers...
Large fluctuations of dissolved oxygen in the Indian and Pacific oceans during Dansgaard-Oeschger oscillations caused by variations of North Atlantic Deep Water subduction
A. Schmittner, E.D. Galbraith, S. W. Hostetler, Thomas F. Pedersen, R. Zhang
2007, Paleoceanography (22)
Paleoclimate records from glacial Indian and Pacific oceans sediments document millennial-scale fluctuations of subsurface dissolved oxygen levels and denitrification coherent with North Atlantic temperature oscillations. Yet the mechanism of this teleconnection between the remote ocean basins remains elusive. Here we present model simulations of the oxygen and nitrogen cycles that...
Oxygen isotopes in nitrite: Analysis, calibration, and equilibration
K.L. Casciotti, John Karl Bohlke, M.R. McIlvin, Stanley J. Mroczkowski, Janet E. Hannon
2007, Analytical Chemistry (79) 2427-2436
Nitrite is a central intermediate in the nitrogen cycle and can persist in significant concentrations in ocean waters, sediment pore waters, and terrestrial groundwaters. To fully interpret the effect of microbial processes on nitrate (NO3-), nitrite (NO2-), and nitrous oxide (N2O) cycling in these systems, the nitrite pool must be...
Composite analysis for Escherichia coli at coastal beaches
E.E. Bertke
2007, Journal of Great Lakes Research (33) 335-341
At some coastal beaches, concentrations of fecal-indicator bacteria can differ substantially between multiple points at the same beach at the same time. Because of this spatial variability, the recreational water quality at beaches is sometimes determined by stratifying a beach into several areas and collecting a sample from each area...
Climate-induced forest dieback as an emergent global phenomenon: Organized oral session at the Ecological Society of America/Society of Ecological Restoration Joint Meeting; San Jose, California, 5-10 August 2007
Craig D. Allen, David D. Breshears
2007, Eos, Transactions, American Geophysical Union (88) 504-504
An organized oral session at the annual meeting of the Ecological Society of America in San Jose, Calif., posed this question: Is climate-induced drought stress triggering increasing rates and unusual patterns of forest die-off at a global scale? Twenty-nine researchers representing five continents reported on patterns, mechanisms, and projections of...
Costimulatory receptors in jawed vertebrates: Conserved CD28, odd CTLA4 and multiple BTLAs
D. Bernard, J.D. Hansen, Pasquier L. Du, M.-P. Lefranc, A. Benmansour, P. Boudinot
2007, Developmental and Comparative Immunology (31) 255-271
CD28 family of costimulatory receptors is comprised of molecules with a single V-type extracellular Ig domain, a transmembrane and an intracytoplasmic region with signaling motifs. CD28 and cytotoxic T lymphocyte antigen-4 (CTLA4) homologs have been recently identified in rainbow trout. Other sequences similar to mammalian CD28 family members have now...
Factors that influence the extraction of polycyclic aromatic hydrocarbons from coal
J. Xue, Gaisheng Liu, Z. Niu, C. L. Chou, C. Qi, Lingyun Zheng, H. Zhang
2007, Energy and Fuels (21) 881-890
Coal samples and carbonaceous mudstone were collected from the Huaibei coalfield, China, and experiments investigating the factors influencing the extraction of the sixteen US EPA (Environmental Protection Agency) priority polycyclic aromatic hydrocarbons (PAHs) were carried out. Different extraction times, solvents, and methods were used. Major interest was focused on finding...
Linking occurrence and fitness to persistence: Habitat-based approach for endangered Greater Sage-Grouse
Cameron L. Aldridge, Mark S. Boyce
2007, Ecological Applications (17) 508-526
Detailed empirical models predicting both species occurrence and fitness across a landscape are necessary to understand processes related to population persistence. Failure to consider both occurrence and fitness may result in incorrect assessments of habitat importance leading to inappropriate management strategies. We took a two-stage approach to identifying critical nesting...
Field assessment of alternative bed-load transport estimators
G. Gaeuman, R. B. Jacobson
2007, Journal of Hydraulic Engineering (133) 1319-1328
Measurement of near-bed sediment velocities with acoustic Doppler current profilers (ADCPs) is an emerging approach for quantifying bed-load sediment fluxes in rivers. Previous investigations of the technique have relied on conventional physical bed-load sampling to provide reference transport information with which to validate the ADCP measurements. However, physical samples are...
Evaluation of sulfate reduction at experimentally induced mixing interfaces using small-scale push-pull tests in an aquifer-wetland system
T.A. Kneeshaw, Jennifer T. McGuire, Erik W. Smith, Isabelle M. Cozzarelli
2007, Applied Geochemistry (22) 2618-2629
This paper presents small-scale push–pull tests designed to evaluate the kinetic controls on SO42-">SO42- reduction in situ at mixing interfaces between a wetland and aquifer impacted by landfill leachate at the Norman Landfill research site, Norman, OK. Quantifying the...
Ephemeroptera, plecoptera, megaloptera, and trichoptera of Great Smoky Mountains National Park
C.R. Parker, O.S. Flint Jr., L.M. Jacobus, B.C. Kondratieff, W.P. McCafferty, J.C. Morse
2007, Conference Paper, Southeastern Naturalist
Great Smoky Mountains National Park (GSMNP), situated on the mountainous border of North Carolina and Tennessee, is recognized as one of the most highly diverse protected areas in the temperate region. In order to provide baseline data for the scientific management of GSMNP, an All Taxa Biodiversity Inventory (ATBI) was...
Mode of occurrence and environmental mobility of oil-field radioactive material at US Geological Survey research site B, Osage-Skiatook Project, northeastern Oklahoma
Robert A. Zielinski, James R. Budahn
2007, Applied Geochemistry (22) 2125-2137
Two samples of produced-water collected from a storage tank at US Geological Survey research site B, near Skiatook Lake in northeastern Oklahoma, have activity concentrations of dissolved 226Ra and 228Ra that are about 1500 disintegrations/min/L (dpm/L). Produced-water also contains minor amounts of small (5–50 μm) suspended grains of Ra-bearing BaSO4 (barite). Precipitation of radioactive...
Can parasites be indicators of free-living diversity? Relationships between species richness and the abundance of larval trematodes and of local benthos and fishes
R. F. Hechinger, K. D. Lafferty, T.C. Huspeni, A.J. Brooks, A. M. Kuris
2007, Oecologia (151) 82-92
Measuring biodiversity is difficult. This has led to efforts to seek taxa whose species richness correlates with the species richness of other taxa. Such indicator taxa could then reduce the time and cost of assessing the biodiversity of the more extensive community. The search for species richness correlations has yielded...
A Ribeiroia spp. (Class: Trematoda) - Specific PCR-based diagnostic
David M. Reinitz, T.P. Yoshino, Rebecca A. Cole
2007, Journal of Parasitology (93) 1234-1238
Increased reporting of amphibian malformations in North America has been noted with concern in light of reports that amphibian numbers and species are declining worldwide. Ribeiroia ondatrae has been shown to cause a variety of types of malformations in amphibians. However, little is known about the prevalence of R. ondatrae...
Does body size influence nest attendance? A comparison of Ross's geese (Chen rossii) and the larger, sympatric lesser snow geese (C. caerulescens caerulescens)
J.E. Jonsson, A. D. Afton, R.T. Alisauskas
2007, Journal of Ornithology (148) 549-555
The body-size hypothesis predicts that nest attendance is positively related to body size among waterfowl and that recess duration is inversely related to body size. Several physiological and behavioral characteristics of Ross's geese (Chen rossii) suggest that females of this species should maintain high nest attendance despite their relatively small...
Lethal and sublethal effects of ammonia to juvenile Lampsilis mussels (Unionidae) in sediment and water-only exposures
T.J. Newton, M.R. Bartsch
2007, Environmental Toxicology and Chemistry (26) 2057-2065
We compared the sensitivity of two juvenile unionid mussels (Lampsilis cardium and Lampsilis higginsii) to ammonia in 96-h water-only and sediment tests by use of mortality and growth measurements. Twenty mussels were placed in chambers buried 2.5 cm into reference sediments to approximate pore-water exposure (sediment tests) or elevated above...
Identification of plasma glucocorticoids in pallid sturgeon in response to stress
M.A.H. Webb, J.A. Allert, K.M. Kappenman, J. Marcos, G.W. Feist, C.B. Schreck, C.H. Shackleton
2007, General and Comparative Endocrinology (154) 98-104
Compared to teleosts, little is known about the stress response in chondrosteans, and the glucocorticoid(s) most responsive to stress have never been definitively determined in sturgeon. In terms of cortisol production, pallid sturgeon (Scaphirhynchus albus) have a low physiological response to stress compared to other sturgeons (Acipenser sp.). Because of...
Selenium and metal concentrations in waterbird eggs and chicks at Agassiz National Wildlife Refuge, Minnesota
T. W. Custer, Christine M. Custer, B.A. Eichhorst, D. Warburton
2007, Archives of Environmental Contamination and Toxicology (53) 103-109
Exceptionally high cadmium (Cd) and chromium (Cr) concentrations were reported in eggs, feathers, or livers of selected waterbird species nesting at Agassiz National Wildlife Refuge (Agassiz) in 1994. Ten- to 15-day-old Franklin's gull (Larus pipixcan), black-crowned night-heron (Nycticorax nycticorax), and eared grebe (Podiceps nigricollis) chicks were collected in 1998, 1999,...
Cadmium ecophysiology in seven stonefly (Plecoptera) species: Delineating sources and estimating susceptibility
C.A. Martin, S. N. Luoma, D.J. Cain, D.B. Buchwalter
2007, Environmental Science & Technology (41) 7171-7177
A major challenge in ecotoxicology lies in generating data under experimental conditions that are relevant to understanding contaminant effects in nature. Biodynamic modeling combines species-specific physiological traits to make predictions of metal bioaccumulation that fare well when tested in the field....
Dissolved organic carbon in Alaskan boreal forest: Sources, chemical characteristics, and biodegradability
Kimberly P. Wickland, Jason C. Neff, George R. Aiken
2007, Ecosystems (10) 1323-1340
The fate of terrestrially-derived dissolved organic carbon (DOC) is important to carbon (C) cycling in both terrestrial and aquatic environments, and recent evidence suggests that climate warming is influencing DOC dynamics in northern ecosystems. To understand what determines the fate of terrestrial DOC, it is essential to quantify the chemical...
Revisiting evolutionary dead ends in sockeye salmon ( Oncorhynchus nerka) life history
S.A. Pavey, T.R. Hamon, J.L. Nielsen
2007, Canadian Journal of Fisheries and Aquatic Sciences (64) 1199-1208
This study challenges recent hypotheses about sockeye salmon (Oncorhynchus nerka) colonization based on life history and broadens the pathways that investigators should consider when studying sockeye colonization of novel habitats. Most sockeye populations exhibit lake-type life histories. Riverine populations are thought to be more likely to stray from their natal...
