A new population of Aleutian shield fern (Polystichum aleuticum C. Christens.) on Adak Island, Alaska
Sandra L. Talbot, Stephen S. Talbot
2002, American Fern Journal (92) 288-293
We report and describe a new population of the endangered Aleutian shield fern (Polystichum aleuticum C. Christens.) discovered on Mount Reed, Adak Island, Alaska. The new population is located at a lower elevation than the other known populations, placing the species' known elevational range between 338 m and 525 m....
Assessment of undiscovered petroleum resources in Central and South America
Christopher J. Schenk
2002, Conference Paper, World Petroleum Congress Proceedings
The USGS has assessed undiscovered conventional oil and gas resources in 128 selected petroleum provinces of the world. Of these 128 provinces, 23 are in South America, Central America, and the Caribbean area. In the USGS 2000 Assessment, the provinces resulted in mean totals for undiscovered resource of 105 billion...
Considerations for sampling inorganic constituents in ground water using diffusion samplers
D.A. Vroblesky, M.D. Petkewich, T.R. Campbell
Gavaskar A.R.Chen A.S.C., editor(s)
2002, Conference Paper, Proceedings of the Third International Conference on Remediation of Chlorinated and Recalcitrant Compounds
Data indicate that nylon-screen and dialysis diffusion samplers are capable of obtaining concentrations of inorganic solutes in ground water from wells that closely correspond to concentrations obtained by low-flow sampling. Conservative solutes, such as chloride, can be sampled by filling the diffusion samplers with oxygenated water. The samplers should be...
Generalized extreme gust wind speeds distributions
E. Cheng, C. Yeung
2002, Journal of Wind Engineering and Industrial Aerodynamics (90) 1657-1669
Since summer 1996, the US wind engineers are using the extreme gust (or 3-s gust) as the basic wind speed to quantify the destruction of extreme winds. In order to better understand these destructive wind forces, it is important to know the appropriate representations of these extreme gust wind speeds....
Population dynamics of bloaters (Coregonus hoyi) in Lake Michigan, 1973-1998
L.M. TeWinkel, T. Kroeff, G.W. Fleischer, M. Toneys
2002, Advances in Limnology (57) 307-320
Past research has demonstrated that the recruitment pattern of Lake Michigan bloaters (Coregonus hoyi) was best represented by a Beverton-Holt function during 1977-1983. In this present study, we re-assessed relations in bloater recruitment and investigated trends in sex ratio and mean length at age as they related to recent changes...
Conceptual uncertainty in crystalline bedrock: Is simple evaluation the only practical approach?
J. Geier, C.I. Voss, B. Dverstorp
2002, Acta Universitatis Carolinae, Geologica (46) 544-548
A simple evaluation can be used to characterise the capacity of crystalline bedrock to act as a barrier to releases of radionuclides from a nuclear waste repository. Physically plausible bounds on groundwater flow and an effective transport-resistance parameter are estimated based on fundamental principles and idealised models of pore geometry....
Application of classification-tree methods to identify nitrate sources in ground water
T.B. Spruill, W.J. Showers, S. S. Howe
2002, Conference Paper, Journal of Environmental Quality
A study was conducted to determine if nitrate sources in ground water (fertilizer on crops, fertilizer on golf courses, irrigation spray from hog (Sus scrofa) wastes, and leachate from poultry litter and septic systems) could be classified with 80% or greater success. Two statistical classification-tree models were devised from 48...
A test of "Annual resolution" in stalagmites using tree rings
J.L. Betancourt, H. D. Grissino-Mayer, M.W. Salzer, T.W. Swetnam
2002, Quaternary Research (58) 197-199
So-called annual banding has been identified in a number of speleothems in which the number of bands approximates the time interval between successive U-series dates. The apparent annual resolution of speleothem records, however, remains largely untested. Here we statistically compare variations in band thickness from a late Holocene stalagmite in...
Vegetation and climate controls on potential CO2, DOC and DON production in northern latitude soils
J. C. Neff, D.U. Hooper
2002, Global Change Biology (8) 872-884
Climatic change may influence decomposition dynamics in arctic and boreal ecosystems, affecting both atmospheric CO2 levels, and the flux of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) to aquatic systems. In this study, we investigated landscape-scale controls on potential production of these compounds using a one-year laboratory incubation...
Sand wave fields beneath the Loop Current, Gulf of Mexico: Reworking of fan sands
Neil H. Kenyon, A.M. Akhmetzhanov, D.C. Twichell
2002, Marine Geology (192) 297-307
Extensive fields of large barchan-like sand waves and longitudinal sand ribbons have been mapped by deep-towed SeaMARC IA sidescan sonar on part of the middle and lower Mississippi Fan that lies in about 3200 m of water. The area is beneath the strongly flowing Loop Current. The bedforms have not...
Long-term evolution of biodegradation and volatilization rates in a crude oil-contaminated aquifer
B.P. Chaplin, G. N. Delin, R.J. Baker, M.A. Lahvis
2002, Bioremediation Journal (6) 237-255
Volatilization and subsequent biodegradation near the water Table make up a coupled natural attenuation pathway that results in significant mass loss of hydrocarbons. Rates of biodegradation and volatilization were documented twice 12 years apart at a crude-oil spill site near Bemidji, Minnesota. Biodegradation rates were determined by calibrating a gas...
Comparison of methods for nutrient measurement in calcareous soils: Ion-exchange resin bag, capsule, membrane, and chemical extractions
S. K. Sherrod, J. Belnap, M. E. Miller
2002, Soil Science (167) 666-679
Four methods for measuring quantities of 12 plant-available nutrients were compared using three sandy soils in a series of three experiments. Three of the methods use different ion-exchange resin forms—bags, capsules, and membranes—and the fourth was conventional chemical extraction. The first experiment compared nutrient extraction data from a medium of...
Population differentiation in the red-legged kittiwake (Rissa brevirostris) as revealed by mitochondrial DNA
A. Patirana, S.A. Hatcher, Vicki L. Friesen
2002, Conservation Genetics (3) 335-340
Population decline in red-legged kittiwakes (Rissa brevirostris) over recent decades has necessitated the collection of information on the distribution of genetic variation within and among colonies for implementation of suitable management policies. Here we present a preliminary study of the extent of genetic structuring and gene flow among the three...
Comparative contaminant toxicity: Are amphibian larvae more sensitive than fish?
C.M. Bridges, F.J. Dwyer, D.K. Hardesty, D.W. Whites
2002, Bulletin of Environmental Contamination and Toxicology (69) 562-569
No abstract available....
Distribution of metals in water and bed sediment in a mineral-rich watershed, Montana, USA
Sonia A. Nagorski, Johnnie N Moore, David B. Smith
2002, Mine Water and the Environment (21) 121-136
We sampled the Blackfoot River (Montana) and its major tributaries from the headwaters of the basin to near its confluence with the Clark Fork River over the course of 5 days in August 1998. We measured streamflow, collected fine-grained (<63 μm) streambed sediment, and sampled the dissolved (operationally defined as...
Sea level response to ENSO along the central California coast: How the 1997-1998 event compares with the historic record
H. F. Ryan, M. Noble
2002, Progress in Oceanography (54) 149-169
Long-term monthly sea level and sea surface temperature (SST) anomalies from central California show that during winter months, positive anomalies are associated with El Niño events and the negative ones with La Niña events. There is no significant impact on monthly mean anomalies associated with Pacific decadal oscillations, although there...
A step increase in streamflow in the conterminous United States
G.J. McCabe, D.M. Wolock
2002, Geophysical Research Letters (29) 38-1-38-4
Annual minimum, median, and maximum daily streamflow for 400 sites in the conterminous United States (U.S.), measured during 1941-1999, were examined to identify the temporal and spatial character of changes in streamflow statistics. Results indicate a noticeable increase in annual minimum and median daily streamflow around 1970, and a less...
Evaluation of unsaturated zone water fluxes in heterogeneous alluvium at a Mojave Basin Site
John R. Nimmo, Jeffrey A. Deason, John A. Izbicki, Peter Martin
2002, Water Resources Research (38) 33-1-33-13
Vertical and horizontal water fluxes in the unsaturated zone near intermittent streams critically affect ecosystems, water supply, and contaminant transport in arid and semiarid regions. The subsurface near the Oro Grande Wash is typical in having great textural diversity, pronounced layer contrasts, and extremely low hydraulic conductivities associated with nearly...
Predictive evaluation of size restrictions as management strategies for tennessee reservoir crappie fisheries
D.A. Isermann, S.M. Sammons, P.W. Bettoli, T.N. Churchill
2002, North American Journal of Fisheries Management (22) 1349-1357
We evaluated the potential effect of minimum size restrictions on crappies Pomoxis spp. in 12 large Tennessee reservoirs. A Beverton-Holt equilibrium yield model was used to predict and compare the response of these fisheries to three minimum size restrictions: 178 mm (i.e., pragmatically, no size limit), 229 mm, and the...
Effects of subcutaneous transmitters on reproduction, incubation behavior, and annual return rates of female wood ducks
Gary R. Hepp, T.H. Folk, Kevin M. Hartke
2002, Wildlife Society Bulletin (30) 1208-1214
Radiotransmitters attached externally to breeding waterfowl can have a variety of negative effects. Implanted transmitters can reduce potential deleterious effects; abdominal implants are used most commonly in waterfowl. Methods also have been developed to implant transmitters subcutaneously, but effects of subcutaneous implants on adult ducks have not been evaluated. In...
The utility of estimating net primary productivity over Alaska using baseline AVHRR data
C. J. Markon, Kim M. Peterson
2002, International Journal of Remote Sensing (23) 4571-4596
Net primary productivity (NPP) is a fundamental ecological variable that provides information about the health and status of vegetation communities. The Normalized Difference Vegetation Index, or NDVI, derived from the Advanced Very High Resolution Radiometer (AVHRR) is increasingly being used to model or predict NPP, especially over large remote areas....
Deep arid system hydrodynamics 1. Equilibrium states and response times in thick desert vadose zones
Michelle Ann Walvoord, Mitchell A. Plummer, Fred M. Phillips, Andrew V. Wolfsberg
2002, Water Resources Research (38) 44-1-44-15
Quantifying moisture fluxes through deep desert soils remains difficult because of the small magnitude of the fluxes and the lack of a comprehensive model to describe flow and transport through such dry material. A particular challenge for such a model is reproducing both observed matric potential and chloride profiles. We...
Carbon dioxide emission rate of Kīlauea Volcano: Implications for primary magma and the summit reservoir
T.M. Gerlach, K.A. McGee, T. Elias, A. J. Sutton, M.P. Doukas
2002, Journal of Geophysical Research B: Solid Earth (107) ECV 3-1-ECV 3-15
We report a CO2 emission rate of 8500 metric tons per day (t d−1) for the summit of Kīlauea Volcano, several times larger than previous estimates. It is based on three sets of measurements over 4 years of synchronous SO2 emission rates and volcanic CO2/SO2concentration ratios for the summit correlation spectrometer (COSPEC)...
Deep arid system hydrodynamics 2. Application to paleohydrologic reconstruction using vadose zone profiles from the northern Mojave Desert
Michelle Ann Walvoord, Fred M. Phillips, Scott W. Tyler, Peter C. Hartsough
2002, Water Resources Research (38) 27-1-27-12
Site‐specific numerical modeling of four sites in two arid alluvial basins within the Nevada Test Site employs a conceptual model of deep arid system hydrodynamics that includes vapor transport, the role of xeric vegetation, and long‐term surface boundary transients. Surface boundary sequences, spanning 110 kyr, that best reproduce measured chloride...
Spatial scales of carbon flow in a river food web
J. C. Finlay, S. Khandwala, M.E. Power
2002, Ecology (83) 1845-1859
Spatial extents of food webs that support stream and river consumers are largely unknown, but such information is essential for basic understanding and management of lotic ecosystems. We used predictable variation in algal δ13C with water velocity, and measurements of consumer δ13C and δ15N to examine carbon flow and trophic...
