Sea otters past and present perspectives
James L. Bodkin
2000, Alaska Geographic (7) 73-93
Sea otters have been an important resource for people living along the North Pacific coast for thousands of years. At least two aspects of the sea otters' natural history have linked them with humans: their pelt and their food habits. Sea otter pelts, arguably the finest in the animal...
Pore fluid pressure, apparent friction, and Coulomb failure
N.M. Beeler, R.W. Simpson, S.H. Hickman, D.A. Lockner
2000, Journal of Geophysical Research B: Solid Earth (105) 25533-25542
Many recent studies of stress-triggered seismicity rely on a fault failure model with a single free parameter, the apparent coefficient of friction, presumed to be a material constant with possible values 0 ≤ μ′ ≤ 1. These studies may present a misleading view of fault strength and the role of...
Fracture process zone in granite
A. Zang, F.C. Wagner, S. Stanchits, C. Janssen, G. Dresen
2000, Journal of Geophysical Research B: Solid Earth (105) 23651-23661
In uniaxial compression tests performed on Aue granite cores (diameter 50 mm, length 100 mm), a steel loading plate was used to induce the formation of a discrete shear fracture. A zone of distributed microcracks surrounds the tip of the propagating fracture. This process zone is imaged by locating acoustic...
Alachlor transformation patterns in aquatic field mesocosms under variable oxygen and nutrient conditions
D.W. Graham, M.K. Miley, F. Denoyelles, Val H. Smith, E.M. Thurman, R. Carter
2000, Water Research (34) 4054-4062
Alachlor is one of the most commonly used herbicides in both Europe and North America. Because of its toxic properties, its fate and attenuation in natural waters is practically important. This paper assesses factors that affect alachlor decay rate in aquatic systems using field-scale experimental units. In particular, we used...
Information technology developments within the national biological information infrastructure
Gladys Cotter, Mike Frame
2000, Mathematics and Computers in Modern Science - Acoustics and Music, Biology and Chemistry, Business and Economics 206-211
Looking out an office window or exploring a community park, one can easily see the tremendous challenges that biological information presents the computer science community. Biological information varies in format and content depending whether or not it is information pertaining to a particular species (i.e. Brown Tree Snake), or a...
Depletion of Appalachian coal reserves - how soon?
R. C. Milici
2000, International Journal of Coal Geology (44) 251-266
Much of the coal consumed in the US since the end of the last century has been produced from the Pennsylvanian strata of the Appalachian basin. Even though quantities mined in the past are less than they are today, this basin yielded from 70% to 80% of the nation's annual...
Geochemical effects of rapid sedimentation in aquatic systems: Minimal diagenesis and the preservation of historical metal signatures
E. Callender
2000, Journal of Paleolimnology (23) 243-260
Rapid sedimentation exerts a pronounced influence on early sedimentary diagenesis in that there is insufficient time for a sediment particle to equilibrate in any one sediment layer before that layer may be displaced vertically by another layer. These sedimentation patterns are common in surface-water reservoirs whose sedimentation rates (1-10 cm...
Combining accuracy assessment of land-cover maps with environmental monitoring programs
S.V. Stehman, R.L. Czaplewski, S.M. Nusser, L. Yang, Z. Zhu
2000, Environmental Monitoring and Assessment (64) 115-126
A scientifically valid accuracy assessment of a large-area, land-cover map is expensive. Environmental monitoring programs offer a potential source of data to partially defray the cost of accuracy assessment while still maintaining the statistical validity. In this article, three general strategies for combining accuracy assessment and environmental monitoring protocols are...
Aquatic ecosystem protection and restoration: Advances in methods for assessment and evaluation
M.B. Bain, A.L. Harig, D.P. Loucks, R.R. Goforth, K.E. Mills
2000, Environmental Science and Policy (3) 89-98
Many methods and criteria are available to assess aquatic ecosystems, and this review focuses on a set that demonstrates advancements from community analyses to methods spanning large spatial and temporal scales. Basic methods have been extended by incorporating taxa sensitivity to different forms of stress, adding measures linked to system...
Characterizing multiple timescales of stream and storage zone interaction that affect solute fate and transport in streams
Jungyill Choi, Judson W. Harvey, Martha H. Conklin
2000, Water Resources Research (36) 1511-1518
The fate of contaminants in streams and rivers is affected by exchange and biogeochemical transformation in slowly moving or stagnant flow zones that interact with rapid flow in the main channel. In a typical stream, there are multiple types of slowly moving flow zones in which exchange and transformation occur,...
Sediment-contact and survival of fingernail clams: Implications for conducting short-term laboratory tests
T.J. Naimo, W.G. Cope, M.R. Bartsch
2000, Environmental Toxicology (15) 23-27
Porewater toxicity tests have been used as indicators of whole sediment toxicity. However, many species commonly tested in porewater predominately reside in the water column and otherwise have little to no direct contact with sediment and associated porewater. We assessed the feasibility of porewater toxicity tests with fingernail clams Musculium...
Evidence for a previously unrecognized species of owlet-nightjar
T.K. Pratt
2000, The Auk (117) 1-11
I studied the systematic relationships of the three large owlet-nightjars (Aegothelidae) to determine the taxonomic status of a fawn-colored lowland form currently classified as Aegotheles insignis tatei. I examined most of the existing specimens of A. i. insignis (n = 158) and A. crinifrons (n = 23) and all known...
High-resolution seismic reflection surveys and modeling across an area of high damage from the 1994 Northridge earthquake, Sherman Oaks, California
William J. Stephenson, Robert A. Williams, Jack K. Odum, David M. Worley
2000, Bulletin of the Seismological Society of America (90) 643-654
Approximately 3.6 km of P-wave seismic-reflection data were acquired along two orthogonal profiles in Sherman Oaks, California to determine whether shallow (less than 1-km depth) geologic structures contributed to the dramatic localized damage resulting from the 1994 Northridge earthquake. Both lines, one along Matilija Avenue and one along Milbank Street,...
Origin of the Colorado River experimental flood in Grand Canyon
E.D. Andrews, L.A. Pizzi
2000, Hydrological Sciences Journal (45) 607-627
The Colorado River is one of the most highly regulated and extensively utilized rivers in the world. Total reservoir storage is approximately four times the mean annual runoff of −17 × 109 m3 year−1. Reservoir storage and regulation have decreased annual peak discharges and hydroelectric power generation has increased daily flow variability....
U-Pb geochronology of zircon and monazite from Mesoproterozoic granitic gneisses of the northern Blue Ridge, Virginia and Maryland, USA
J. N. Aleinikoff, W.C. Burton, P. T. Lyttle, A. E. Nelson, C.S. Southworth
2000, Precambrian Research (99) 113-146
Mesoproterozoic granitic gneisses comprise most of the basement of the northern Blue Ridge geologic province in Virginia and Maryland. Lithology, structure, and U-Pb geochronology have been used to subdivide the gneisses into three groups. The oldest rocks, Group 1, are layered granitic gneiss (1153 ?? 6 Ma), hornblende monzonite gneiss...
Ground deformation at Merapi Volcano, Java, Indonesia: distance changes, June 1988-October 1995
K.D. Young, B. Voight, Subandriyo, Sajiman, Miswanto, T. J. Casadevall
2000, Journal of Volcanology and Geothermal Research (100) 233-259
Edifice deformations are reported here for the period 1988–1995 at Merapi volcano, one of the most active and dangerous volcanoes in Indonesia. The study period includes a major resumption in lava effusion in January 1992 and a major dome collapse in November 1994. The data comprise electronic distance measurements (EDM)...
Problems associated with estimating ground water discharge and recharge from stream-discharge records
K. J. Halford, G.C. Mayer
2000, Ground Water (38) 331-342
Ground water discharge and recharge frequently have been estimated with hydrograph-separation techniques, but the critical assumptions of the techniques have not been investigated. The critical assumptions are that the hydraulic characteristics of the contributing aquifer (recession index) can be estimated from stream-discharge records; that periods of exclusively ground water discharge...
A field technique for estimating aquifer parameters using flow log data
Frederick L. Paillet
2000, Ground Water (38) 510-521
A numerical model is used to predict flow along intervals between producing zones in open boreholes for comparison with measurements of borehole flow. The model gives flow under quasi-steady conditions as a function of the transmissivity and hydraulic head in an arbitrary number of zones communicating with each other along...
Numerical model of frazil ice and suspended sediment concentrations and formation of sediment laden ice in the Kara Sea
C. R. Sherwood
2000, Journal of Geophysical Research C: Oceans (105) 14061-14080
A one-dimensional (vertical) numerical model of currents, mixing, frazil ice concentration, and suspended sediment concentration has been developed and applied in the shallow southeastern Kara Sea. The objective of the calculations is to determine whether conditions suitable for turbid ice formation can occur during times of rapid cooling and wind-...
Responses of stable bay-margin and barrier-island systems to Holocene sea-level highstands, western Gulf of Mexico
Robert A. Morton, Jeffrey G. Paine, Michael D. Blum
2000, Journal of Sedimentary Research (70) 478-490
The microtidal, wave-dominated coast of the western Gulf of Mexico displays a variety of Holocene geomorphic features indicating higher-than-present water levels that were previously attributed to storm processes while geoidal sea level was at its present position. Field and aerial-photograph examinations of bay margins, barrier islands, and beach-ridge plains following...
Channel stability downstream from a dam assessed using aerial photographs and stream-gage information
K. E. Juracek
2000, Journal of the American Water Resources Association (36) 633-645
The stability of the Neosho River channel downstream from John Redmond Dam, in southeast Kansas, was investigated using multiple-date aerial photographs and stream-gage information. Bankfull channel width was used as the primary indicator variable to assess pre- and post-dam channel change. Five six-mile river reaches and four stream gages were...
Pesticides in the atmosphere of the Mississippi River Valley, part I: Rain
M.S. Majewski, W.T. Foreman, D. A. Goolsby
2000, Science of Total Environment (248) 201-212
Weekly composite rainfall samples were collected in three paired urban and agricultural regions of the Midwestern United States and along the Mississippi River during April–September 1995. The paired sampling sites were located in Mississippi, Iowa, and Minnesota. A background site, removed from dense urban and agriculture...
Occurrence of sulfonylurea, sulfonamide, imidazolinone, and other herbicides in rivers, reservoirs and ground water in the Midwestern United States, 1998
W.A. Battaglin, E. T. Furlong, M.R. Burkhardt, C.J. Peter
2000, Science of Total Environment (248) 123-133
Sulfonylurea (SU), sulfonamide (SA), and imidazolinone (IMI) herbicides are relatively new classes of chemical compounds that function by inhibiting the action of a plant enzyme, stopping plant growth, and eventually killing the plant. These compounds generally have low mammalian toxicity, but plants demonstrate a...
Quantitative model of the growth of floodplains by vertical accretion
J. A. Moody, B.M. Troutman
2000, Earth Surface Processes and Landforms (25) 115-133
A simple one-dimensional model is developed to quantitatively predict the change in elevation, over a period of decades, for vertically accreting floodplains. This unsteady model approximates the monotonic growth of a floodplain as an incremental but constant increase of net sediment deposition per flood for those floods of a partial...
Plants as indicators of focused ground water discharge to a northern Minnesota lake
D.O. Rosenberry, Robert G. Striegl, D.C. Hudson
2000, Ground Water (38) 296-303
Determining the discharge of ground water to Shingobee Lake (66 ha), north-central Minnesota, is complicated by the presence of numerous springs situated adjacent to the lake and in the shallow portion of the lakebed. Springs first had to be located before these areas of more rapid discharge could be quantified....
