Evaluating the source of streamwater nitrate using δ15N and δ18O in nitrate in two watersheds in New Hampshire, USA
Linda H. Pardo, Carol Kendall, Jennifer Pett-Ridge, Cecily C.Y. Chang
2004, Hydrological Processes (18) 2699-2712
The natural abundance of nitrogen and oxygen isotopes in nitrate can be a powerful tool for identifying the source of nitrate in streamwater in forested watersheds, because the two main sources of nitrate, atmospheric deposition and microbial nitrification, have distinct δ18O values. Using a simple mixing model, we estimated the...
Physical properties and rock physics models of sediment containing natural and laboratory-formed methane gas hydrate
W.J. Winters, I.A. Pecher, W.F. Waite, D.H. Mason
2004, American Mineralogist (89) 1221-1227
This paper presents results of shear strength and acoustic velocity (p-wave) measurements performed on: (1) samples containing natural gas hydrate from the Mallik 2L-38 well, Mackenzie Delta, Northwest Territories; (2) reconstituted Ottawa sand samples containing methane gas hydrate formed in the laboratory; and (3) ice-bearing sands. These measurements show that...
Mineralogical and geochemical controls on the release of trace elements from slag produced by base- and precious-metal smelting at abandoned mine sites
N.M. Piatak, R.R. Seal II, J. M. Hammarstrom
2004, Conference Paper, Applied Geochemistry
Slag collected from smelter sites associated with historic base-metal mines contains elevated concentrations of trace elements such as Cu, Zn and Pb. Weathering of slag piles, many of which were deposited along stream banks, potentially may release these trace elements into the environment. Slags were sampled from the Ely and...
Stratigraphy and sedimentology of the Upper Cretaceous (Campanian) Anacacho Limestone, Texas, USA
C.S. Swezey, E.C. Sullivan
2004, Cretaceous Research (25) 473-497
The Upper Cretaceous Anacacho Limestone is exposed in outcrops between the cities of San Antonio and Del Rio, Texas. A detailed study of four outcrops (Blanco Creek section, Sabinal River section, Seco Creek section, Hondo Creek section) shows that the Anacacho Limestone rests on the Upson Clay (which contains fauna...
Delineation and evaluation of hydrologic-landscape regions in the United States using geographic information system tools and multivariate statistical analyses.
David M. Wolock, Thomas C. Winter, Gerard McMahon
2004, Environmental Management (34) S71-S88
Hydrologic-landscape regions in the United States were delineated by using geographic information system (GIS) tools combined with principal components and cluster analyses. The GIS and statistical analyses were applied to land-surface form, geologic texture (permeability of the soil and bedrock), and climate variables that describe the physical and climatic setting...
Engelmann Spruce (Picea engelmannii) as a biological monitor of changes in soil metal loading related to past mining activity
K.M. Witte, R. B. Wanty, W.I. Ridley
2004, Applied Geochemistry (19) 1367-1376
Engelmann spruce (Picea engelmannii) is the dominant tree species in many abandoned mine areas of the Rocky Mountains. It is long-lived, and therefore, may act as a long term biological monitor of changes in soil chemistry caused by past mining activity. In this study, laser ablation inductively coupled mass spectrometry...
Using lidar and effective LAI data to evaluate IKONOS and Landsat 7 ETM+ vegetation cover estimates in a ponderosa pine forest
X. Chen, Lee Vierling, E. Rowell, Tom DeFelice
2004, Remote Sensing of Environment (91) 14-26
Structural and functional analyses of ecosystems benefit when high accuracy vegetation coverages can be derived over large areas. In this study, we utilize IKONOS, Landsat 7 ETM+, and airborne scanning light detection and ranging (lidar) to quantify coniferous forest and understory grass coverages in a ponderosa pine (Pinus ponderosa) dominated...
Hydrologic scales, cloud variability, remote sensing, and models: Implications for forecasting snowmelt and streamflow
James J. Simpson, M. D. Dettinger, F. Gehrke, T.J. McIntire, Gary L. Hufford
2004, Weather and Forecasting (19) 251-276
Accurate prediction of available water supply from snowmelt is needed if the myriad of human, environmental, agricultural, and industrial demands for water are to be satisfied, especially given legislatively imposed conditions on its allocation. Robust retrievals of hydrologic basin model variables (e.g., insolation or areal extent of...
Visual enhancement of unmixed multispectral imagery using adaptive smoothing
G.P. Lemeshewsky
Z.-U. Rahman, R.A. Schowengerdt, S.E. Reichenbach, editor(s)
2004, Conference Paper, Proceedings of SPIE - The International Society for Optical Engineering
Adaptive smoothing (AS) has been previously proposed as a method to smooth uniform regions of an image, retain contrast edges, and enhance edge boundaries. The method is an implementation of the anisotropic diffusion process which results in a gray scale image. This paper discusses modifications to the AS method for...
Assessing subglacial processes from diatom fragmentation patterns
R.P. Scherer, C.M. Sjunneskog, N.R. Iverson, T.S. Hooyer
2004, Geology (32) 557-560
Reconstructing the size and glacial style of past ice-sheet advances requires interpreting complex glacial sedimentary facies. We use diatoms, a major component of Antarctic continental shelf deposits, to infer the physical conditions under which these deposits were emplaced. The degree of diatom fragmentation and the presence of diatoms of varying...
Mentor - Mentoree, what is in a relationship?
L. R. Handley
2004, Conference Paper, Geographical Bulletin - Gamma Theta Upsilon
[No abstract available]...
Threatened fishes of the world: Notropis topeka Gilbert, 1884 (Cyprinidae)
S.S. Wall, C. R. Berry Jr.
2004, Environmental Biology of Fishes (70) 246
[No abstract available]...
Redistribution and growth of the Caspian Tern population in the Pacific Coast region of North America, 1981-2000
R.M. Suryan, D. P. Craig, D.D. Roby, N.D. Chelgren, K. Collis, W.D. Shuford, Donald E. Lyons
2004, Condor (106) 777-790
We examined nesting distribution and demography of the Pacific Coast population of Caspian Terns (Sterna caspia) using breeding records and band recoveries spanning two decades since the first population assessment. Since 1980, population size has more than doubled to about 12 900 pairs, yet the proportion of the population nesting...
Estimating functional connectivity of wildlife habitat and its relevance to ecological risk assessment
A.R. Johnson, Craig R. Allen, K.A.N. Simpson
Lawrence Kapustka, Gregory R. Biddinger, Matthew Luxon, Hector Galbraith, editor(s)
2004, ASTM Selected Technical Papers STP1458
Habitat fragmentation is a major threat to the viability of wildlife populations and the maintenance of biodiversity. Fragmentation relates to the sub-division of habitat into disjunct patches. Usually coincident with fragmentation per se is loss of habitat, a reduction in the size of the remnant patches, and increasing distance between patches. Natural...
Overwintered Bullfrog tadpoles negatively affect Salamanders and Anurans in native amphibian communities
M.D. Boone, E. E. Little, R. D. Semlitsch
2004, Copeia 683-690
We examined the interactive effects of overwintered Bullfrog (Rana catesbeiana) tadpoles and pond hydroperiod on a community of larval amphibians in outdoor mesocosms including American Toads (Bufo americanus), Southern Leopard Frogs (Rana sphenocephala), and Spotted Salamanders (Ambystoma maculatum) - species within the native range of Bullfrogs. Spotted Salamanders and Southern...
Nutrient reserves of Lesser Scaup (Aythya affinis) during spring migration in the Mississippi Flyway: A test of the spring condition hypothesis
M.J. Anteau, A. D. Afton
2004, The Auk (121) 917-929
The continental scaup population (Lesser [Aythya affinis] and Greater [A. marila] combined) has declined markedly since 1978. One hypothesis for the population decline states that reproductive success has decreased because female scaup are arriving on breeding areas in poorer body condition than they did historically (i.e. spring condition hypothesis). We...
Global geologic context for rock types and surface alteration on Mars
M.B. Wyatt, H.Y. McSween Jr., K. L. Tanaka, J. W. Head III
2004, Geology (32) 648-654
Petrologic interpretations of thermal emission spectra from Mars orbiting spacecraft indicate the widespread occurrence of surfaces having basaltic and either andesitic or partly altered basalt compositions. Global concentration of ice-rich mantle deposits and near-surface ice at middle to high latitudes and their spatial correlation with andesitic or partly altered basalt...
Drainage effects on stream nitrate-N and hydrology in south-central Minnesota (USA)
J.A. Magner, G. A. Payne, J. Steffen
2004, Environmental Monitoring and Assessment (91) 183-198
Excessive nitrate-N in south-central Minnesota ditches and streams is related to land-use change, and may be contributing to the development of the zone of hypoxia in the Gulf of Mexico. Intensive land-use (agricultural management) has progressively increased as subsurface drainage has improved crop productivity over the past 25 years. We...
Wave run-up on a high-energy dissipative beach
P. Ruggiero, R.A. Holman, R.A. Beach
2004, Journal of Geophysical Research C: Oceans (109)
Because of highly dissipative conditions and strong alongshore gradients in foreshore beach morphology, wave run-up data collected along the central Oregon coast during February 1996 stand in contrast to run-up data currently available in the literature. During a single data run lasting approximately 90 min, the significant vertical run-up elevation...
Water loss in the Potomac River basin during droughts
E.R. Hagen, J.E. Kiang, J.J.A. Dillow
Sehlke G.Hayes D.F.Stevens D.K., editor(s)
2004, Conference Paper, Proceedings of the 2004 World Water and Environmetal Resources Congress: Critical Transitions in Water and Environmetal Resources Management
The water loss phenomena in the Washington DC metropoliton area's (WMA) Potomac River water supply basin during droughts was analyzed. Gage errors, permitted withdrawals, evaporation, and transpiration by trees along the river were investigated to account for loss. The Interstate Commission on the Potomac River Basin (ICPRB) calculated potential gage...
The effects of habitat resolution on models of avian diversity and distributions: A comparison of two land-cover classifications
Joshua J. Lawler, Raymond. J. O’Connor, Carolyn T. Hunsaker, K. Bruce Jones, Thomas R. Loveland, Denis White
2004, Landscape Ecology (19) 517-532
Quantifying patterns is a key element of landscape analysis. One aspect of this quantification of particular importance to landscape ecologists is the classification of continuous variables to produce categorical variables such as land-cover type or elevation stratum. Although landscape ecologists are fully aware of the importance of spatial resolution in...
Tectonic histories between Alba Patera and Syria Planum, Mars
R. C. Anderson, J. M. Dohm, A. F. C. Haldemann, T.M. Hare, V.R. Baker
2004, Icarus (171) 31-38
Syria Planum and Alba Patera are two of the most prominent features of magmatic-driven activity identified for the Tharsis region and perhaps for all of Mars. In this study, we have performed a Geographic Information System-based comparative investigation of their tectonic histories using published geologic map information and Mars Orbiter...
Age structure and mortality of walleyes in Kansas reservoirs: Use of mortality caps to establish realistic management objectives
M.C. Quist, J.L. Stephen, C.S. Guy, R.D. Schultz
2004, North American Journal of Fisheries Management (24) 990-1002
Age structure, total annual mortality, and mortality caps (maximum mortality thresholds established by managers) were investigated for walleye Sander vitreus (formerly Stizostedion vitreum) populations sampled from eight Kansas reservoirs during 1991-1999. We assessed age structure by examining the relative frequency of different ages in the population; total annual mortality of...
Localization and physical property experiments conducted by opportunity at Meridiani Planum
R. E. Arvidson, R. C. Anderson, P. Bartlett, J.F. Bell III, P. R. Christensen, P. Chu, K. Davis, B.L. Ehlmann, M.P. Golombek, S. Gorevan, E.A. Guinness, A. F. C. Haldemann, Kenneth E. Herkenhoff, G. Landis, R. Li, R. Lindemann, D. W. Ming, T. Myrick, T. Parker, L. Richter, F.P. Seelos IV, Laurence A. Soderblom, S. W. Squyres, R.J. Sullivan, Jim Wilson
2004, Science (306) 1730-1733
The location of the Opportunity landing site was determined to better than 10-m absolute accuracy from analyses of radio tracking data. We determined Rover locations during traverses with an error as small as several centimeters using engineering telemetry and overlapping images. Topographic profiles generated from rover data show that the...
The influence of groundwater chemistry on arsenic concentrations and speciation in a quartz sand and gravel aquifer
D.B. Kent, P.M. Fox
2004, Geochemical Transactions (5) 1-12
We examined the chemical reactions influencing dissolved concentrations, speciation, and transport of naturally occurring arsenic (As) in a shallow, sand and gravel aquifer with distinct geochemical zones resulting from land disposal of dilute sewage effluent. The principal geochemical zones were: (1) the uncontaminated zone above the sewage...
