A controlled experiment in ground water flow model calibration
M. C. Hill, R.L. Cooley, D.W. Pollock
1998, Groundwater (36) 520-535
Nonlinear regression was introduced to ground water modeling in the 1970s, but has been used very little to calibrate numerical models of complicated ground water systems. Apparently, nonlinear regression is thought by many to be incapable of addressing such complex problems. With what we believe...
Boron-rich mud volcanoes of the Black Sea region: Modern analogues to ancient sea-floor tourmalinites associated with Sullivan-type Pb-Zn deposits?
J. F. Slack, R.J.W. Turner, P.L.G. Ware
1998, Geology (26) 439-442
Large submarine mud volcanoes in the abyssal part of the Black Sea south of the Crimean Peninsula are similar in many respects to synsedimentary mud volcanoes in the Mesoproterozoic Belt-Purcell basin. One of the Belt-Purcell mud volcanoes directly underlies the giant Sullivan Pb-Zn-Ag...
Geochemical surveillance of magmatic volatiles at Popocatepetl volcano, Mexico
F. Goff, C. J. Janik, H. Delgado, C. Werner, D. Counce, J.A. Stimac, C. Siebe, S.P. Love, S.N. Williams, T. Fischer, L. Johnson
1998, Geological Society of America Bulletin (110) 695-710
Surveillance of Popocatépetl volcanic plume geochemistry and SO2 flux began in early 1994 after fumarolic and seismic activity increased significantly during 1993. Volatile traps placed around the summit were collected at near-monthly intervals until the volcano erupted on December 21, 1994. Additional trap samples...
Impact cratering through geologic time
E.M. Shoemaker, C.S. Shoemaker
1998, Journal of the Royal Astronomical Society of Canada (92) 297-309
New data on lunar craters and recent discoveries about craters on Earth permit a reassessment of the bombardment history of Earth over the last 3.2 billion years. The combined lunar and terrestrial crater records suggest that the long-term average rate of production of craters larger than 20 km in diameter...
Vulnerability to predation and physiological stress responses in juvenile chinook salmon (Oncorhynchus tshawytscha) experimentally infected with Renibacterium salmoninarum
M.G. Mesa, T.P. Poe, A.G. Maule, C.B. Schreck
1998, Canadian Journal of Fisheries and Aquatic Sciences (55) 1599-1606
We experimentally infected juvenile chinook salmon (Oncorhynchus tshawytscha) with Renibacterium salmoninarum (Rs), the causative agent of bacterial kidney disease (BKD), to examine the vulnerability to predation of fish with differing levels of Rs infection and assess physiological change during progression of the disease. Immersion challenges conducted during 1992 and 1994...
Soil carbon stocks and their rates of accumulation and loss in a boreal forest landscape
G. Rapalee, S.E. Trumbore, E.A. Davidson, Jennifer W. Harden, H. Veldhuis
1998, Global Biogeochemical Cycles (12) 687-701
Boreal forests and wetlands are thought to be significant carbon sinks, and they could become net C sources as the Earth warms. Most of the C of boreal forest ecosystems is stored in the moss layer and in the soil. The objective of this study was to estimate soil C...
Implications for the use of diflubenzuron to reduce arthropod populations inhabiting evaporation ponds of the San Joaquin Valley, California
C.S. McCasland, R.J. Cooper, D. A. Barnum
1998, Bulletin of Environmental Contamination and Toxicology (60) 702-708
[No abstract available]...
A comparison of methods for deriving solute flux rates using long-term data from streams in the mirror lake watershed
P.A. Bukaveckas, G.E. Likens, T. C. Winter, D.C. Buso
1998, Water, Air, & Soil Pollution (105) 277-293
Calculation of chemical flux rates for streams requires integration of continuous measurements of discharge with discrete measurements of solute concentrations. We compared two commonly used methods for interpolating chemistry data (time-averaging and flow-weighting) to determine whether discrepancies between the two methods were large relative to other sources of error in...
Birds of the Indigirka River Delta, Russia: Historical and biogeographic comparisons
John M. Pearce, Daniel Esler, Andrei G. Degtyarev
1998, Arctic (51) 361-370
We documented the breeding status and relative abundance of all avian species on the coastal portion of the Indigirka River Delta during spring and summer 1993-95. Data on avifaunal composition were then compared to data from adjacent areas from Eastern Siberia to the Chukotka Peninsula to evaluate how species composition...
The role of introduced species in the degradation of island ecosystems: A case history of guam
T. H. Fritts, G.H. Rodda
1998, Annual Review of Ecology and Systematics (29) 113-140
The accidental introduction of the brown treesnake (Boiga irregularis) on Guam around 1950 induced a cascade of extirpations that may be unprecedented among historical extinction events in taxonomic scope and severity. Birds, bats, and reptiles were affected, and by 1990 most forested areas on Guam retained only three native vertebrates,...
Long-term effects of a lock and dam and greentree reservoir management on a bottomland hardwood forest
S.L. King, J. A. Allen, J.W. McCoy
1998, Forest Ecology and Management (112) 213-226
We investigated the long-term effects of a lock and dam and greentree reservoir management on a riparian bottomland hardwood forest in southern Arkansas, USA, by monitoring stress, mortality, and regeneration of bottomland hardwood trees in 53 permanent sampling plots from 1987-1995. The lock and dam and greentree reservoir management have...
Effects of climatic variation on field metabolism and water relations of desert tortoises
B.T. Henen, C.C. Peterson, I.R. Wallis, K.H. Berry, K.A. Nagy
1998, Oecologia (117) 365-373
We used the doubly labeled water method to measure the field metabolic rates (FMRs, in kJ kg-1 day-1) and water flux rates (WIRs, in ml H2O kg-1 day-1) of adult desert tortoises (Gopherus agassizii) in three parts of the Mojave Desert in California over a 3.5-year period, in order to...
Spatial and temporal study of nitrate concentration in groundwater by means of coregionalization
V. D’Agostino, E.A. Greene, G. Passarella, M. Vurro
1998, Environmental Geology (36) 285-295
Spatial and temporal behavior of hydrochemical parameters in groundwater can be studied using tools provided by geostatistics. The cross-variogram can be used to measure the spatial increments between observations at two given times as a function of distance (spatial structure). Taking into account the existence of such a spatial structure,...
DNA and allozyme markers provide concordant estimates of population differentiation: Analyses of U.S. and Canadian populations of Yukon River fall-run chum salmon (Oncorhynchus keta)
Kim T. Scribner, Penelope A. Crane, William J. Spearman, Lisa W. Seeb
1998, Canadian Journal of Fisheries and Aquatic Sciences (55) 1748-1758
Although the number of genetic markers available for fisheries research has steadily increased in recent years, there is limited information on their relative utility. In this study, we compared the performance of different "classes" of genetic markers (mitochondrial DNA (mtDNA), nuclear DNA (nDNA), and allozymes) in terms of estimating levels and...
Tracing solute mobility at the Panola Mountain Research Watershed, Georgia, USA: Variations in Na+, Cl-, and H4SiO4 concentrations
N.E. Peters, E.B. Ratcliffe, M. Tranter
1998, IAHS-AISH Publication (248) 483-490
Concentration variations of sodium (N+). chloride (Cl-). and dissolved silica (H4SiO4) in rainfall, throughfall, soil water, groundwater and streamwater were evaluated at the Panola Mountain Research Watershed near Atlanta, Georgia, to determine how variations in concentrations of these solutes provide greater understanding of water quality evolution at the hillslope and...
Nonlinear refraction and reflection travel time tomography
Jiahua Zhang, Uri S. ten Brink, M.N. Toksoz
1998, Journal of Geophysical Research B: Solid Earth (103) 29743-29757
We develop a rapid nonlinear travel time tomography method that simultaneously inverts refraction and reflection travel times on a regular velocity grid. For travel time and ray path calculations, we apply a wave front method employing graph theory. The first-arrival refraction travel times are calculated on the basis of cell...
Chemistry of unsaturated zone gases sampled in open boreholes at the crest of Yucca Mountain, Nevada: Data and basic concepts of chemical and physical processes in the mountain
Donald C. Thorstenson, Edwin P. Weeks, Herbert Haas, Eurybiades Busenberg, Niel Plummer, Charles A. Peters
1998, Water Resources Research (34) 1507-1529
Boreholes open to the unsaturated zone at the crest of Yucca Mountain, Nevada, were variously sampled for CO2 (including 13C and 14C), CH4, N2, O2, Ar, CFC-11, CFC-12, and CFC-113 from 1986 to 1993. Air enters the mountain in outcrops, principally on the eastern slope, is enriched in CO2by mixing with soil gas,...
Range expansion by wild hogs across the central United States
P. S. Gipson, B. Hlavachick, T. Berger
1998, Wildlife Society Bulletin (26) 279-286
[No abstract available]...
Classification of surface types using SIR-C/X-SAR, Mount Everest Area, Tibet
Thomas P. Albright, Thomas H. Painter, Dar A. Roberts, Jiancheng Shi, Jeff Dozier, Eric Fielding
1998, Journal of Geophysical Research E: Planets (103) 25823-25833
Imaging radar is a promising tool for mapping snow and ice cover in alpine regions. It combines a high-resolution, day or night, all-weather imaging capability with sensitivity to hydrologic and climatic snow and ice parameters. We use the spaceborne imaging radar-C/X-band synthetic aperture radar (SIR-C/X-SAR) to map snow and glacial...
Issues and prospects for the next generation of the spatial data transfer standard (SDTS)
D. Arctur, D. Hair, G. Timson, E.P. Martin, R. Fegeas
1998, International Journal of Geographical Information Science (12) 403-425
The Spatial Data Transfer Standard (SDTS) was designed to be capable of representing virtually any data model, rather than being a prescription for a single data model. It has fallen short of this ambitious goal for a number of reasons, which this paper investigates. In addition to issues that might...
Riverine based eco-tourism: Trinity River non-market benefits estimates
A. J. Douglas, J. G. Taylor
1998, International Journal of Sustainable Development and World Ecology (5) 136-148
California's Central Valley Project (CVP) was approved by voters in a statewide referendum in 1933. CVP referendum approval initiated funding for construction of important water development projects that had far reaching effects on regional water supplies. The construction of Trinity Dam in 1963 and the subsequent transbasin diversion of Trinity...
Fluid-rock reactions in an evaporitic melange, Permian Haselgebirge, Austrian Alps
C. Spotl, F.J. Longstaffe, K. Ramseyer, Michael J. Kunk, R. Wiesheu
1998, Sedimentology (45) 1019-1044
Tectonically isolated blocks of carbonate rocks present within the anhydritic Haselgebirge melange of the Northern Calcareous Alps record a complex history of deformation and associated deep-burial diagenetic to very low-grade metamorphic reactions. Fluids were hot (up to ~ 250 ??C) and reducing brines charged with carbon dioxide. Individual carbonate outcrops...
Habitat characteristics affecting fish assemblages on a Hawaiian coral reef
A. M. Friedlander, J.D. Parrish
1998, Journal of Experimental Marine Biology and Ecology (224) 1-30
Habitat characteristics of a reef were examined as potential influences on fish assemblage structure, using underwater visual census to estimate numbers and biomass of all fishes visible on 42 benthic transects and making quantitative measurements of 13 variables of the corresponding physical habitat and sessile biota. Fish assemblages in the...
Long-term dynamics of Typha populations
J.B. Grace, R.G. Wetzel
1998, Aquatic Botany (61) 137-146
The zonation of Typha populations in an experimental pond in Michigan was re-examined 15 years after the original sampling to gain insight into the long-term dynamics. Current distributions of Typha populations were also examined in additional experimental ponds at the site that have been maintained for 23 years. The zonation...
Artificial maturation of an immature sulfur- and organic matter-rich limestone from the Ghareb Formation, Jordan
M.P. Koopmans, W.I.C. Rijpstra, J. W. De Leeuw, M. D. Lewan, J.S.S. Damste
1998, Organic Geochemistry (28) 503-521
An immature (Ro=0.39%), S-rich (S(org)/C = 0.07), organic matter-rich (19.6 wt. % TOC) limestone from the Ghareb Formation (Upper Cretaceous) in Jordan was artificially matured by hydrous pyrolysis (200, 220 ..., 300??C; 72 h) to study the effect of progressive diagenesis and early catagenesis on the amounts and distributions of...
