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...
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...
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...
Experimental evaluation of factors affecting temporal variability of water samples obtained from long-screened wells
T. E. Reilly, D.R. LeBlanc
1998, Ground Water (36) 566-576
As a well is pumped through time, concentrations of specific constituents in the water discharging from the well may change as a result of their transport within the well and the aquifer. A series of experiments conducted at a research site on Cape Cod, Massachusetts, examined the effects of transport...
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...
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...
Re-Os ages for Archean molybdenite and pyrite, Kuittila-Kivisuo, Finland and Proterozoic molybdenite, Kabeliai, Lithuania: Testing the chronometer in a metamorphic and metasomatic setting
H. J. Stein, K. Sundblad, R.J. Markey, J. W. Morgan, G. Motuza
1998, Mineralium Deposita (33) 329-345
Seven 187Re-187Os ages were determined for molybdenite and pyrite samples from two well-dated Precambrian intrusions in Fennoscandia to examine the sustainability of the Re-Os chronometer in a metamorphic and metasomatic setting. Using a new 187Re decay constant (1.666 x 10-11y-1) with a much improved uncertainty (±0.31%), we determined replicate Re-Os...
Drought-induced shift of a forest-woodland ecotone: Rapid landscape response to climate variation
Craig D. Allen, David D. Breshears
1998, Proceedings of the National Academy of Sciences of the United States of America (95) 14839-14842
In coming decades, global climate changes are expected to produce large shifts in vegetation distributions at unprecedented rates. These shifts are expected to be most rapid and extreme at ecotones, the boundaries between ecosystems, particularly those in semiarid landscapes. However, current models do not adequately provide for such rapid effects—particularly...
Modelling of instream flow needs: The link between sediment and aquatic habitat
Robert T. Milhous
1998, Regulated Rivers: Research & Management (14) 79-94
Instream flows are needed to remove undesirable accumulations of sediment. Fines and sand accumulate on and in gravels during periods of low flow and must be removed (flushed) periodically in order for the gravel to continue as suitable habitat for aquatic animals. Sediment of all sizes can also fill pools...
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...
The Fremont complex: A behavioral perspective
D.B. Madsen, S.R. Simms
1998, Journal of World Prehistory (12) 255-336
The Fremont complex is composed of farmers and foragers who occupied the Colorado Plateau and Great Basin region of western North America from about 2100 to 500 years ago. These people included both immigrants and indigenes who shared some material culture and symbolic attributes, but also varied in ways not...
Radar attenuation tomography using the centroid frequency downshift method
L. Liu, J. W. Lane, Y. Quan
1998, Journal of Applied Geophysics (40) 105-116
A method for tomographically estimating electromagnetic (EM) wave attenuation based on analysis of centroid frequency downshift (CFDS) of impulse radar signals is described and applied to cross-hole radar data. The method is based on a constant-Q model, which assumes a linear frequency dependence of attenuation...
Non-water-ice constituents in the surface material of the icy Galilean satellites from the Galileo near-infrared mapping spectrometer investigation
T. B. McCord, G. B. Hansen, Roger N. Clark, P. D. Martin, C. A. Hibbitts, F. P. Fanale, J. C. Granahan, M. Segura, D. L. Matson, T. V. Johnson, R. W. Carlson, W. D. Smythe, G. E. Danielson
1998, Journal of Geophysical Research E: Planets (103) 8603-8626
We present evidence for several non‐ice constituents in the surface material of the icy Galilean satellites, using the reflectance spectra returned by the Galileo near infrared mapping spectrometer (NIMS) experiment. Five new absorption features are described at 3.4, 3.88, 4.05, 4.25, and 4.57 μm for Callisto and Ganymede, and some...
Spatial variations in the frequency-magnitude distribution of earthquakes at Soufriere Hills Volcano, Montserrat, West Indies
J.A. Power, M. Wyss, J.L. Latchman
1998, Geophysical Research Letters (25) 3653-3656
The frequency-magnitude distribution of earthquakes measured by the b-value is determined as a function of space beneath Soufriere Hills Volcano, Montserrat, from data recorded between August 1, 1995 and March 31, 1996. A volume of anomalously high b-values (b > 3.0) with a 1.5 km...
The use of coupled atmospheric and hydrological models for water-resources management in headwater basins
G. Leavesley, L. Hay
1998, IAHS-AISH Publication (248) 259-265
Coupled atmospheric and hydrological models provide an opportunity for the improved management of water resources in headwater basins. Issues currently limiting full implementation of coupled-model methodologies include (a) the degree of uncertainty in the accuracy of precipitation and other meteorological variables simulated by atmospheric models, and (b) the problem of...
The geochemical record in rock glaciers
E.J. Steig, J. J. Fitzpatrick, N. Potter Jr., D.H. Clark
1998, Geografiska Annaler, Series A: Physical Geography (80) 277-286
A 9.5 m ice core was extracted from beneath the surficial debris cover of a rock glacier at Galena Creek, northwestern Wyoming. The core contains clean, bubble-rich ice with silty debris layers spaced at roughly 20 cm intervals. The debris layers are similar in appearance...
Base cation concentrations in subsurface flow from a forested hillslope: The role of flushing frequency
Douglas A. Burns, Richard P. Hooper, Jeffrey J. McDonnell, James E. Freer, Carol Kendall, Keith Beven
1998, Water Resources Research (34) 3535-3544
A 20-m-wide trench was excavated to bedrock on a hillslope at the Panola Mountain Research Watershed in the Piedmont region of Georgia to determine the effect of upslope drainage area from the soil and bedrock surfaces on the geochemical evolution of base cation concentrations in subsurface flow. Samples were collected...
Use of the Moon for spacecraft calibration over 350-2500 nm
H. H. Kieffer, J.M. Anderson
1998, Conference Paper, Proceedings of SPIE - The International Society for Optical Engineering
The Moon is the only natural object outside the Earth's atmosphere that is within the dynamic range of most imaging instruments on Earth-orbiting spacecraft. The excellent photometric stability of the Lunar surface will allow its use as a long-term instrument calibration source once the dependence of Lunar spectral radiance on...
Causes of sinks near Tucson, Arizona, USA
J.P. Hoffmann, D. R. Pool, A.D. Konieczki, M. C. Carpenter
1998, Hydrogeology Journal (6) 349-364
Land subsidence in the form of sinks has occurred on and near farmlands near Tucson, Pima County, Arizona, USA. The sinks occur in alluvial deposits along the flood plain of the Santa Cruz River, and have made farmlands dangerous and unsuitable for farming. More than 1700...
Proactive responses to human impacts that balance development and Atlantic salmon (Salmo salar) conservation: An integrative model
M.A. Wilzbach, M. E. Mather, C.L. Folt, A. Moore, R.J. Naiman, A.F. Youngson, J. McMenemy
1998, Conference Paper, Canadian Journal of Fisheries and Aquatic Sciences
Incorporating human impacts into conservation plans is critical to protect natural resources. Using a model that examines how anthropogenic changes might be proactively influenced to promote conservation, we argue that a denser human population does not spell inevitable doom for Atlantic salmon (Salmo salar). Humans affect the Atlantic salmon ecosystem...
Analysis of simulated advanced spaceborne thermal emission and reflection (ASTER) radiometer data of the Iron Hill, Colorado, study area for mapping lithologies
L. C. Rowan
1998, Journal of Geophysical Research D: Atmospheres (103) 32291-32306
The advanced spaceborne thermal emission and reflection (ASTER) radiometer was designed to record reflected energy in nine channels with 15 or 30 m resolution, including stereoscopic images, and emitted energy in five channels with 90 m resolution from the NASA Earth Observing System AMI platform. A simulated ASTER data set...
Interactions between pool geometry and hydraulics
Douglas M. Thompson, Jonathan M. Nelson, Ellen E. Wohl
1998, Water Resources Research (34) 3673-3681
An experimental and computational research approach was used to determine interactions between pool geometry and hydraulics. A 20-m-long, 1.8-m-wide flume was used to investigate the effect of four different geometric aspects of pool shape on flow velocity. Plywood sections were used to systematically alter constriction width, pool depth, pool length,...
Geodynamics of magmatic Cu-Ni-PGE sulfide deposits: New insights from the Re-Os isotope system
D.D. Lambert, J.G. Foster, L.R. Frick, E.M. Ripley, M. L. Zientek
1998, Economic Geology (93) 121-136
In this study, we reassess crustal contamination and sulfide ore-forming processes in some of the largest magmatic ore deposits, using published Re-Os isotope data and a modeling methodology that incorporates the R factor, defined as the effective mass of silicate magma with which a given mass of sulfide magma has...
Correlating N2 and CH4 adsorption on microporous carbon using a new analytical model
Jielun Sun, S. Chen, M.J. Rood, M. Rostam-Abadi
1998, Energy and Fuels (12) 1071-1078
A new pore size distribution (PSD) model is developed to readily describe PSDs of microporous materials with an analytical expression. Results from this model can be used to calculate the corresponding adsorption isotherm to compare the calculated isotherm to the experimental isotherm. This aspect of the model provides another check...
Trace element abundances of high-MgO glasses from Kilauea, Mauna Loa and Haleakala volcanoes, Hawaii
T.P. Wagner, David A. Clague, E.H. Hauri, T.L. Grove
1998, Contributions to Mineralogy and Petrology (131) 13-21
We performed an ion-microprobe study of eleven high-MgO (6.7-14.8 wt%) tholeiite glasses from the Hawaiian volcanoes Kilauea, Mauna Loa and Haleakala. We determined the rare earth (RE), high field strength, and other selected trace element abundances of these glasses, and used the data to establish their relationship to typical Hawaiian...
