Distribution of light and heavy fractions of soil organic carbon as related to land use and tillage practice
Zhengxi Tan, R. Lal, L. Owens, R. C. Izaurralde
2007, Soil and Tillage Research (92) 53-59
Mass distributions of different soil organic carbon (SOC) fractions are influenced by land use and management. Concentrations of C and N in light- and heavy fractions of bulk soils and aggregates in 0–20 cm were determined to evaluate the role of aggregation in SOC sequestration under conventional tillage (CT), no-till (NT),...
Seabirds as indicators of marine ecosystems: Introduction: A modern role for seabirds as indicators
John F. Piatt, William J. Sydeman, Francis Wiese
2007, Marine Ecology Progress Series (352) 199-204
A key requirement for implementing ecosystem-based management is to obtain timely information on significant fluctuations in the ecosystem (Botsford et al. 1997). However, obtaining all necessary information about physical and biological changes at appropriate temporal and spatial scales is a daunting task. Intuitively, one might assume that physical data are more...
Characterization of nutrient, organic carbon, and sediment loads and concentrations from the Mississippi River into the northern Gulf of Mexico
R.E. Turner, N. N. Rabalais, Richard B. Alexander, G. McIsaac, R. W. Howarth
2007, Estuaries and Coasts (30) 773-790
We synthesize and update the science supporting the Action Plan for Reducing, Mitigating, and Controlling Hypoxia in the Northern Gulf of Mexico (Mississippi River/Gulf of Mexico Watershed Nutrient Task Force 2001) with a focus on the spatial and temporal discharge and patterns of nutrient and organic carbon delivery to the...
Seasonal and interannual variability in the taxonomic composition and production dynamics of phytoplankton assemblages in Crater Lake, Oregon
McIntire C. David, Gary L. Larson, Robert E. Truitt
2007, Hydrobiologia (574) 179-204
Taxonomic composition and production dynamics of phytoplankton assemblages in Crater Lake, Oregon, were examined during time periods between 1984 and 2000. The objectives of the study were (1) to investigate spatial and temporal patterns in species composition, chlorophyll concentration, and primary productivity relative to seasonal patterns of water circulation; (2)...
A rapid method to characterize seabed habitats and associated macro-organisms
T.J. Anderson, G.R. Cochrane, D.A. Roberts, H. Chezar, G. Hatcher
Todd B.J.Greene H.G., editor(s)
2007, Special Paper - Geological Association of Canada 71-79
This study presents a method for rapidly collecting, processing, and interrogating real-time abiotic and biotic seabed data to determine seabed habitat classifications. This is done from data collected over a large area of an acoustically derived seabed map, along multidirectional transects, using a towed small camera-sled. The seabed, within the...
Thermal maturation history of the Wilcox group (Paleocene-Eocene), Texas: Results of regional-scale multi-1D modeling
E. L. Rowan, Peter D. Warwick, Janet K. Pitman
Lorcan Kennan, James Pindell, Norman C. Rosen, editor(s)
2007, Conference Paper, The Paleogene of the Gulf of Mexico and Caribbean basins: Processes, events, and petroleum systems
The thermal maturation history of the Paleocene-Eocene Wilcox Group has been reconstructed based on burial history models of 53 wells in the Texas coastal plain. This modeling study has been conducted in conjunction with a geologically based assessment of the oil and gas resources in Cenozoic strata of the Gulf...
Using pebble lithology and roundness to interpret gravel provenance in piedmont fluvial systems of the Rocky Mountains, USA
D. A. Lindsey, W. H. Langer, B. S. Van Gosen
2007, Sedimentary Geology (199) 223-232
Clast populations in piedmont fluvial systems are products of complex histories that complicate provenance interpretation. Although pebble counts of lithology are widely used, the information provided by a pebble count has been filtered by a potentially large number of processes and circumstances. Counts of pebble lithology and roundness together offer...
Weirs: Counting and sampling adult salmonids in streams and rivers
Christian E. Zimmerman, Laura M. Zabkar
2007, Book chapter, Salmonid field protocols handbook: techniques for assessing status and trends in salmon and trout populations.
Weirs—which function as porous barriers built across stream—have long been used to capture migrating fish in flowing waters. For example, the Netsilik peoples of northern Canada used V-shaped weirs constructed of river rocks gathered onsite to capture migrating Arctic char Salvelinus alpinus (Balikci 1970). Similarly, fences constructed of stakes and...
A model for estimating passive integrated transponder (PIT) tag antenna efficiencies for interval-specific emigration rates
G.E. Horton, T.L. Dubreuil, B. H. Letcher
2007, Transactions of the American Fisheries Society (136) 1165-1176
Our goal was to understand movement and its interaction with survival for populations of stream salmonids at long-term study sites in the northeastern United States by employing passive integrated transponder (PIT) tags and associated technology. Although our PIT tag antenna arrays spanned the stream channel (at most flows) and were...
Characterization of microtopography and its influence on vegetation patterns in created wetlands
K. Moser, C. Ahn, Gregory E. Noe
2007, Wetlands (27) 1081-1097
Created wetlands are increasingly used to mitigate wetland loss. Thus, identifying wetland creation methods that enhance ecosystem development might increase the likelihood of mitigation success. Noting that the microtopographic variation found in natural wetland settings may not commonly be found in created wetlands, this study explores relationships between induced microtopography,...
Improved outgassing models for the Landsat-5 thematic mapper
E. Micijevic, G. Chander, R. W. Hayes
2007, Conference Paper, International Geoscience and Remote Sensing Symposium (IGARSS)
The Landsat-5 (L5) Thematic Mapper (TM) detectors of the short wave infrared (SWIR) bands 5 and 7 are maintained on cryogenic temperatures to minimize thermal noise and allow adequate detection of scene energy. Over the instrument's lifetime, gain oscillations are observed in these bands that are caused by an ice-like...
Comparison of four approaches to a rock facies classification problem
M.K. Dubois, Geoffrey C. Bohling, S. Chakrabarti
2007, Computers & Geosciences (33) 599-617
In this study, seven classifiers based on four different approaches were tested in a rock facies classification problem: classical parametric methods using Bayes' rule, and non-parametric methods using fuzzy logic, k-nearest neighbor, and feed forward-back propagating artificial neural network. Determining the most effective classifier for geologic facies prediction in wells...
Biological uptake of polychlorinated biphenyls by Macoma balthica from sediment amended with activated carbon
Pamela B. McLeod, Martine J. van den Heuvel-Greve, S. N. Luoma, R.G. Luthy
2007, Environmental Toxicology and Chemistry (26) 980-987
This work characterizes the efficacy of activated carbon amendment in reducing polychlorinated biphenyl (PCB) bioavailability to clams (Macoma balthica) from field-contaminated sediment (Hunters Point Naval Shipyard, San Francisco Bay, CA, USA). Test methods were developed for the use of clams to investigate the effects of...
Return to the wild: Translocation as a tool in conservation of the desert tortoise (Gopherus agassizii)
K.J. Field, C.R. Tracy, P.A. Medica, R.W. Marlow, P.S. Corn
2007, Biological Conservation (136) 232-245
Translocation could be used as a tool in conservation of the threatened Mojave Desert Tortoise (Gopherus agassizii) by moving individuals from harm's way and into areas where they could contribute to conservation of the species. Numerous factors may affect the success of translocations, including the conditions experienced by tortoises in...
Recent climate trends and implications for water resources in the Catskill Mountain region, New York, USA
Douglas A. Burns, Julian Klaus, Michael R. McHale
2007, Journal of Hydrology (336) 155-170
Climate scientists have concluded that the earth’s surface air temperature warmed by 0.6 °C during the 20th century, and that warming induced by increasing concentrations of greenhouse gases is likely to continue in the 21st century, accompanied by changes in the hydrologic cycle. Climate change has important implications in the Catskill...
Isotopic characterization of three groundwater recharge sources and inferences for selected aquifers in the upper Klamath Basin of Oregon and California, USA
P.C. Palmer, M. W. Gannett, S.R. Hinkle
2007, Journal of Hydrology (336) 17-29
Stable isotope (??D and ??18O) signatures of three principal groundwater recharge areas in the 21,000-km2 upper Klamath Basin are used to infer recharge sources for aquifers in the interior parts of the basin. Two of the principal recharge areas, the Cascade Range on the western and southern margin of the...
PVTx properties of the CO2-H2O and CO2-H2O-NaCl systems below 647 K: assessment of experimental data and thermodynamic models
Jiawen Hu, Zhenhao Duan, Chen Zhu, I.-M. Chou
2007, Chemical Geology (238) 249-267
Evaluation of CO2 sequestration in formation brine or in seawater needs highly accurate experimental data or models of pressure–volume–temperature-composition (PVTx) properties for the CO2–H2O and CO2–H2O–NaCl systems. This paper presents a comprehensive review of the experimental PVTx properties and the thermodynamic models of these two systems. The following conclusions are drawn from the...
Human influence on California fire regimes
A.D. Syphard, V. C. Radeloff, Jon E. Keeley, T. J. Hawbaker, M.K. Clayton, S. I. Stewart, R. B. Hammer
2007, Ecological Applications (17) 1388-1402
Periodic wildfire maintains the integrity and species composition of many ecosystems, including the mediterranean-climate shrublands of California. However, human activities alter natural fire regimes, which can lead to cascading ecological effects. Increased human ignitions at the wildland-urban interface (WUI) have recently gained attention, but fire activity and risk are typically...
Correcting acoustic Doppler current profiler discharge measurement bias from moving-bed conditions without global positioning during the 2004 Glen Canyon Dam controlled flood on the Colorado River
J. W. Gartner, N. K. Ganju
2007, Limnology and Oceanography: Methods (5) 156-162
Discharge measurements were made by acoustic Doppler current profiler at two locations on the Colorado River during the 2004 controlled flood from Glen Canyon Dam, Arizona. Measurement hardware and software have constantly improved from the 1980s such that discharge measurements by acoustic profiling instruments are now routinely made over a...
Latin hypercube approach to estimate uncertainty in ground water vulnerability
J.J. Gurdak, J.E. McCray, G. Thyne, S.L. Qi
2007, Ground Water (45) 348-361
A methodology is proposed to quantify prediction uncertainty associated with ground water vulnerability models that were developed through an approach that coupled multivariate logistic regression with a geographic information system (GIS). This method uses Latin hypercube sampling (LHS) to illustrate the propagation of input error and estimate uncertainty associated with...
Comparison of the dust distributions in the innermost comae of comets-1P/Halley and 19P/Borrelly spacecraft observations
T.-M. Ho, N. Thomas, D. C. Boice, M. Combi, L.A. Soderblom, V. Tenishev
2007, Planetary and Space Science (55) 974-985
We present a comparative study of the inner comae of comets 1P/Halley and 19P/Borrelly using data from the Halley Multicolour Camera (HMC) onboard Giotto and the Miniature Integrated Camera and Spectrometer onboard Deep Space 1 (DS1). We show that the dust brightness dependence as a function of radial distance is...
Shoreline change as a proxy for subaerial beach volume change
Amy S. Farris, Jeffrey H. List
2007, Journal of Coastal Research (23) 740-748
It is difficult and expensive to calculate changes in sediment volume for large sections of sandy beaches. Shoreline change could be a useful proxy for volume change because it can be collected quickly and relatively easily over long distances. In this paper, we summarize several studies that find a high...
Understanding shallow gas occurrences in the Gulf of Lions
Ana Garcia-Garcia, Tommaso Tesi, Daniel L. Orange, T. Lorenson, Stefano Miserocchi, L. Langone, I. Herbert, J. Dougherty
2007, Geo-Marine Letters (27) 143-154
New coring data have been acquired along the western Gulf of Lions showing anomalous concentrations of methane (up to 95,700 ppm) off the Rhône prodelta and the head of the southern canyons Lacaze-Duthiers and Cap de Creus. Sediment cores were acquired with box and kasten cores during...
Bedrock aquifers and population growth in the Denver Basin, Colorado, USA
J.E. Moore, R.G. Raynolds, M. Dechesne
2007, Episodes (30) 115-118
The Denver Basin bedrock aquifer system consists of Tertiary and Cretaceous age sedimentary rocks known as the Dawson, Denver, Arapahoe and Laramie-Fox Hills aquifers. The number of bedrock wells has increased from 12,000 in 1985 to over 33,700 in 2001 and the withdrawal of groundwater has caused water level declines...
A simple daily soil-water balance model for estimating the spatial and temporal distribution of groundwater recharge in temperate humid areas
W. R. Dripps, K. R. Bradbury
2007, Hydrogeology Journal (15) 433-444
Quantifying the spatial and temporal distribution of natural groundwater recharge is usually a prerequisite for effective groundwater modeling and management. As flow models become increasingly utilized for management decisions, there is an increased need for simple, practical methods to delineate recharge zones and quantify recharge rates. Existing models for estimating...
