Adaptive data-driven models for estimating carbon fluxes in the Northern Great Plains
B.K. Wylie, E. A. Fosnight, T.G. Gilmanov, A.B. Frank, J.A. Morgan, Marshall R. Haferkamp, T.P. Meyers
2007, Remote Sensing of Environment (106) 399-413
Rangeland carbon fluxes are highly variable in both space and time. Given the expansive areas of rangelands, how rangelands respond to climatic variation, management, and soil potential is important to understanding carbon dynamics. Rangeland carbon fluxes associated with Net Ecosystem Exchange (NEE) were measured from multiple year data sets at...
Vapor transfer prior to the October 2004 eruption of Mount St. Helens, Washington
A.J.R. Kent, J. Blundy, K. V. Cashman, K.M. Copper, C. Donnelly, John S. Pallister, M. Reagan, M.C. Rowe, Carl Thornber
2007, Geology (35) 231-234
Dome lavas from the 2004 eruption of Mount St. Helens show elevated Li contents in plagioclase phenocrysts at the onset of dome growth in October 2004. These cannot be explained by variations in plagioclase-melt partitioning, but require elevated Li contents in coexisting melt, a fact confirmed by measurements of Li...
Past and future changes in climate and hydrological indicators in the US Northeast
K. Hayhoe, C.P. Wake, T.G. Huntington, L. Luo, M.D. Schwartz, J. Sheffield, E. Wood, B. Anderson, J. Bradbury, A. DeGaetano, T.J. Troy, D. Wolfe
2007, Climate Dynamics (28) 381-407
To assess the influence of global climate change at the regional scale, we examine past and future changes in key climate, hydrological, and biophysical indicators across the US Northeast (NE). We first consider the extent to which simulations of twentieth century climate from nine atmosphere-ocean general circulation models (AOGCMs) are...
Sediment delivery after a wildfire
Steven L. Reneau, D. Katzman, G.A. Kuyumjian, A. Lavine, D.V. Malmon
2007, Geology (35) 151-154
We use a record of sedimentation in a small reservoir within the Cerro Grande burn area, New Mexico, to document postfire delivery of ash, other fine-grained sediment carried in suspension within floods, and coarse-grained sediment transported as bedload over a five-year period. Ash...
Methane gas hydrate effect on sediment acoustic and strength properties
W.J. Winters, W.F. Waite, D.H. Mason, L.Y. Gilbert, I.A. Pecher
2007, Journal of Petroleum Science and Engineering (56) 127-135
To improve our understanding of the interaction of methane gas hydrate with host sediment, we studied: (1) the effects of gas hydrate and ice on acoustic velocity in different sediment types, (2) effect of different hydrate formation mechanisms on measured acoustic properties (3) dependence of shear strength on pore space...
Can modeling improve estimation of desert tortoise population densities?
K.E. Nussear, C.R. Tracy
2007, Ecological Applications (17) 579-586
The federally listed desert tortoise (Gopherus agassizii) is currently monitored using distance sampling to estimate population densities. Distance sampling, as with many other techniques for estimating population density, assumes that it is possible to quantify the proportion of animals available to be counted in any census. Because desert tortoises spend...
Trends in monitoring pharmaceuticals and personal-care products in the aquatic environment by use of passive sampling devices
G.A. Mills, B. Vrana, I. Allan, D.A. Alvarez, J.N. Huckins, R. Greenwood
2007, Analytical and Bioanalytical Chemistry (387) 1153-1157
The use of passive sampling in monitoring pharmaceuticals and personal-care products (PPCPs) in the aquatic environment is discussed. The utility of passive sampling methods for monitoring the fraction of heavy metals and the biologically available fraction of non-polar organic priority pollutants is recognized and these technologies are being used in...
Effects of season, rainfall, and hydrogeomorphic setting on mangrove tree growth in Micronesia
K. W. Krauss, B. D. Keeland, J. A. Allen, K. C. Ewel, Daniel J. Johnson
2007, Biotropica (39) 161-170
Seasonal patterns of tree growth are often related to rainfall, temperature, and relative moisture regimes. We asked whether diameter growth of mangrove trees in Micronesia, where seasonal changes are minimal, is continuous throughout a year or conforms to an annual cycle. We installed dendrometer bands on Sonneratia alba and Bruguiera...
Development of an SPE/CE method for analyzing HAAs
L. Zhang, P. D. Capel, R.M. Hozalski
2007, Journal - American Water Works Association (99) 83-94
A method to analyze haloacetic acids (HAAs) in drinking water was developed using a capillary electrophoresis (CE) ion analyzer for analyte separation and detection. The effects of background electrolyte (BGE) composition, sample injection approach, and on- and offcapillary preconcentration techniques on HAA peak resolution and method sensitivity were evaluated. The...
Random forests for classification in ecology
D.R. Cutler, T.C. Edwards Jr., K.H. Beard, A. Cutler, K.T. Hess, J. Gibson, J.J. Lawler
2007, Ecology (88) 2783-2792
Classification procedures are some of the most widely used statistical methods in ecology. Random forests (RF) is a new and powerful statistical classifier that is well established in other disciplines but is relatively unknown in ecology. Advantages of RF compared to other statistical classifiers include (1) very high classification accuracy;...
Heat transport in the Red Lake Bog, Glacial Lake Agassiz Peatlands
J.M. McKenzie, D. I. Siegel, Donald O. Rosenberry, P.H. Glaser, Clifford I. Voss
2007, Hydrological Processes (21) 369-378
We report the results of an investigation on the processes controlling heat transport in peat under a large bog in the Glacial Lake Agassiz Peatlands. For 2 years, starting in July 1998, we recorded temperature at 12 depth intervals from 0 to 400 cm within a vertical peat profile at...
Waveform inversion of volcano-seismic signals for an extended source
M. Nakano, Hiroyuki Kumagai, B. Chouet, P. Dawson
2007, Journal of Geophysical Research B: Solid Earth (112)
[1] We propose a method to investigate the dimensions and oscillation characteristics of the source of volcano-seismic signals based on waveform inversion for an extended source. An extended source is realized by a set of point sources distributed on a grid surrounding the centroid of...
Diel changes in water chemistry in an arsenic-rich stream and treatment-pond system
C.H. Gammons, T.M. Grant, David A. Nimick, S.R. Parker, M.D. DeGrandpre
2007, Science of the Total Environment (384) 433-451
Arsenic concentrations are elevated in surface waters of the Warm Springs Ponds Operable Unit (WSPOU), located at the head of the upper Clark Fork River Superfund site, Montana, USA. Arsenic is derived from historical deposition of smelter emissions (Mill and Willow Creeks) and historical mining and milling wastes (Silver Bow...
Chronic toxicity of copper and ammonia to juvenile freshwater mussels (Unionidae)
N. Wang, C.G. Ingersoll, I.E. Greer, D.K. Hardesty, C.D. Ivey, J.L. Kunz, W. G. Brumbaugh, F.J. Dwyer, A.D. Roberts, T. Augspurger, C.M. Kane, R. J. Neves, M.C. Barnhart
2007, Environmental Toxicology and Chemistry (26) 2048-2056
The objectives of the present study were to develop methods for conducting chronic toxicity tests with juvenile mussels under flow-through conditions and to determine the chronic toxicity of copper and ammonia to juvenile mussels using these methods. In two feeding tests, two-month-old fatmucket (Lampsilis siliquoidea) and rainbow mussel (Villosa iris)...
Modeling barrier island response to sea-level rise in the Outer Banks, North Carolina
Laura J. Moore, Jeffrey H. List, S. Jeffress Williams, David Stolper
2007, Conference Paper, Coastal Sediments '07 - Proceedings of 6th International Symposium on Coastal Engineering and Science of Coastal Sediment Processes
An 8500-year Holocene simulation developed in GEOMBEST provides a possible scenario to explain the evolution of barrier coast between Rodanthe and Cape Hatteras, NC. Sensitivity analyses suggest that in the Outer Banks, the rate of sea-level rise is the most important factor in determining how barrier islands evolve. The Holocene...
Coral-gravel storm ridges: examples from the tropical Pacific and Caribbean
Bruce M. Richmond, Robert A. Morton
2007, Conference Paper, Coastal Sediments '07 - Proceedings of 6th International Symposium on Coastal Engineering and Science of Coastal Sediment Processes
Extreme storms in reef environments have long been recognized as a mechanism for depositing ridges of reef-derived coarse clastic sediment. This study revisits the storm ridges formed by Tropical Cyclone Bebe on Funafuti, Tuvalu and Tropical Cyclone Ofa on Upolu, Western Samoa in the South Pacific, and Hurricane Lenny on...
Forage nutritive quality in the Serengeti ecosystem: The roles of fire and herbivory
T.M. Anderson, M.E. Ritchie, E. Mayemba, S. Eby, J.B. Grace, S.J. McNaughton
2007, American Naturalist (170) 343-357
Fire and herbivory are important determinants of nutrient availability in savanna ecosystems. Fire and herbivory effects on the nutritive quality of savanna vegetation can occur directly, independent of changes in the plant community, or indirectly, via effects on the plant community. Indirect effects can be further subdivided into those occurring...
Climate change and forests of the future: Managing in the face of uncertainty
C. I. Millar, N.L. Stephenson, S.L. Stephens
2007, Ecological Applications (17) 2145-2151
We offer a conceptual framework for managing forested ecosystems under an assumption that future environments will be different from present but that we cannot be certain about the specifics of change. We encourage flexible approaches that promote reversible and incremental steps, and that favor ongoing learning and capacity to modify...
Is statistical power to detect trends a good assessment of population monitoring?
N.E. Seavy, M.H. Reynolds
2007, Biological Conservation (140) 187-191
The ability to detect trends in population abundance is of obvious interest to wildlife managers. In recent years, the probability of detecting defined population trends has been the most common method of assessing monitoring programs. Such analyses require many assumptions, including a model for population change and a model for...
Comparative diets of subyearling Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) in the Salmon River, New York
J. H. Johnson
2007, Journal of Great Lakes Research (33) 906-911
Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) have established naturalized populations throughout the Great Lakes. Young-of-year of these species occur sympatrically for about one month in Lake Ontario tributaries. This study examined the diets of subyearling Chinook salmon and steelhead relative to available food in the Salmon River, New...
Petrology and geochemistry of primitive lower oceanic crust from Pito Deep: Implications for the accretion of the lower crust at the Southern East Pacific Rise
N.W. Perk, L.A. Coogan, J.A. Karson, E.M. Klein, H.D. Hanna
2007, Contributions to Mineralogy and Petrology (154) 575-590
A suite of samples collected from the uppermost part of the plutonic section of the oceanic crust formed at the southern East Pacific Rise and exposed at the Pito Deep has been examined. These rocks were sampled in situ by ROV and lie beneath a complete upper crustal section providing...
Regional beach/cliff system dynamics along the california coast
C.J. Hapke, Don Reid
2007, Conference Paper, Coastal Sediments '07 - Proceedings of 6th International Symposium on Coastal Engineering and Science of Coastal Sediment Processes
The coast of California is comprised of both sandy shorelines and cliffed coastline, and in many areas these features spatially coincide. In order to better understand the regional trends of change along the California coast, the U.S. Geological Survey is quantifying both sandy shoreline change and coastal cliff retreat for...
Three-dimensional P-wave velocity structure derived from local earthquakes at the Katmai group of volcanoes, Alaska
A.D. Jolly, S.C. Moran, S.R. McNutt, D.B. Stone
2007, Journal of Volcanology and Geothermal Research (159) 326-342
The three-dimensional P-wave velocity structure beneath the Katmai group of volcanoes is determined by inversion of more than 10,000 rays from over 1000 earthquakes recorded on a local 18 station short-period network between September 1996 and May 2001. The inversion is well constrained from sea level to about 6 km below...
Hindcasting potential hurricane impacts on rapidly changing barrier islands
H.F. Stockdon, D.M. Thompson, A. H. Sallenger Jr.
2007, Conference Paper, Coastal Sediments '07 - Proceedings of 6th International Symposium on Coastal Engineering and Science of Coastal Sediment Processes
Hindcasts of the coastal impact of Hurricane Ivan on Santa Rosa Island, Florida, using a storm-impact scaling model that compares hurricane-induced water levels to local dune morphology, were found to have an accuracy of 68% in predicting the occurrence of one of four impact regimes: swash, collision, overwash, and inundation....
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...
