Transient calcite fracture fillings in a welded tuff, Snowshoe Mountain, Colorado
A.R. Hoch, M.M. Reddy, M.J. Heymans
2000, Applied Geochemistry (15) 1495-1504
The core from two boreholes (13.1 and 19.2 m depth) drilled 500 m apart in the fractured, welded tuff near the summit of the Snowshoe Mountain, Colorado (47??30'N, 106??55'W) had unique petrographic and hydrodynamic properties. Borehole SM-4 had highly variable annual water levels, in contrast to SM-1a, whose water level...
What is “natural”? : Yellowstone elk population - A case study
R.B. Keigley, Frederic H. Wagner
2000, Integrative Biology (1) 133-148
Ecology analyzes the structure and function of ecosystems at all points along the continuum of human disturbance, from so-called pristine forests to urban backyards. Undisturbed systems provide reference points at one end of the spectrum, and nature reserves and parks are highly valued because they can provide unique examples of...
Mechanisms of population differentiation in marbled murrelets: historical versus contemporary processes
B.C. Congdon, John F. Piatt, Kathy Martin, Vicki L. Friesen
2000, Evolution (54) 974-986
Mechanisms of population differentiation in highly vagile species such as seabirds are poorly understood. Previous studies of marbled murrelets (Brachyramphus marmoratus; Charadriiformes: Alcidae) found significant population genetic structure, but could not determine whether this structure is due to historical vicariance (e.g., due to Pleistocene glaciers), isolation by distance, drift or...
Sustainability of the Lake Superior fish community: Interactions in a food web context
James F. Kitchell, Sean P. Cox, Chris J. Harvey, Timothy B. Johnson, Doran M. Mason, Kurt K. Schoen, Kerim Aydin, Charles Bronte, Mark Ebener, Michael Hansen, Michael Hoff, Steve Schram, Don Schreiner, Carl J. Walters
2000, Ecosystems (3) 545-560
The restoration and rehabilitation of the native fish communities is a long-term goal for the Laurentian Great Lakes. In Lake Superior, the ongoing restoration of the native lake trout populations is now regarded as one of the major success stories in fisheries management. However, populations of the deepwater morphotype (siscowet...
A dynamic landscape model for fish in the Everglades and its application to restoration
H.D. Gaff, D.L. DeAngelis, L.J. Gross, R. Salinas, M. Shorrosh
2000, Ecological Modelling (127) 33-52
A model (ALFISH) for fish functional groups in freshwater marshes of the greater Everglades area of southern Florida has been developed. Its main objective is to assess the spatial pattern of fish densities through time across freshwater marshes. This model has the capability of providing a dynamic measure of the...
Test of a modified habitat suitability model for bighorn sheep
L. C. Zeigenfuss, F. J. Singer, M.A. Gudorf
2000, Restoration Ecology (8) 38-46
Translocation of bighorn sheep (Ovis canadensis) is time, labor, and cost intensive and, therefore, high levels of success are desirable. We tested a widely used habitat suitability model against translocation success and then modified it to include additional factors which improved its usefulness in predicting appropriate translocation sites. The modified...
Statistical and procedural issues in the use of heated taxidermic mounts
G.S. Bakken, K.P. Kenow, C. E. Korschgen, A.F. Boysen
2000, Journal of Thermal Biology (25) 317-321
Studies using mounts have an inherently nested error structure; calibration and standardization should use the appropriate procedures and statistics. One example is that individual mount differences are nested within morphological factors related to species, age, or gender; without replication, mount differences may be confused with differences due to morphology. Also,...
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...
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...
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...
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...
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...
Viscoelastic-coupling model for the earthquake cycle driven from below
J.C. Savage
2000, Journal of Geophysical Research B: Solid Earth (105) 25525-25532
In a linear system the earthquake cycle can be represented as the sum of a solution which reproduces the earthquake cycle itself (viscoelastic-coupling model) and a solution that provides the driving force. We consider two cases, one in which the earthquake cycle is driven by stresses transmitted along the schizosphere...
Bedrock knobs, San Francisco Bay: Do navigation hazards outweigh other environment problems?
Paul R. Carlson, John L. Chin, Florence L. Wong
2000, Environmental & Engineering Geoscience (6) 41-55
Three bedrock knobs (Arch, Harding, and Shag rocks) rise above the unconsolidated sediment of central San Francisco Bay to a water depth of less than -12 m (<-39.4 ft MLLW). These rocks are within the westbound vessel traffic area, and the northernmost, Harding Rock, is approximately 300 m (984 ft)...
Synthetic aperture radar interferometry of Okmok volcano, Alaska: radar observations
Zhong Lu, Dorte Mann, Jeffrey T. Freymueller, David Meyer
2000, Journal of Geophysical Research B: Solid Earth (105) 10791-10806
ERS-1/ERS-2 synthetic aperture radar interferometry was used to study the 1997 eruption of Okmok volcano in Alaska. First, we derived an accurate digital elevation model (DEM) using a tandem ERS-1/ERS-2 image pair and the preexisting DEM. Second, by studying changes in interferometric coherence we found that the newly erupted lava...
Identifying populations potentially exposed to agricultural pesticides using remote sensing and a Geographic Information System
Mary H. Ward, John R. Nuckols, Stephanie J. Weigel, Susan K. Maxwell, Kenneth P. Cantor, Ryan S. Miller
2000, Environmental Health Perspectives (108) 5-12
Pesticides used in agriculture may cause adverse health effects among the population living near agricultural areas. However, identifying the populations most likely to be exposed is difficult. We conducted a feasibility study to determine whether satellite imagery could be used to reconstruct historical crop patterns. We used historical Farm Service...
Rates of sediment supply and sea-level rise in a large coastal lagoon
R.A. Morton, G.H. Ward, W.A. White
2000, Marine Geology (167) 261-284
Laguna Madre, Texas, is 3-7 km wide and more than 190 km long, making it one of the longest lagoons in the world. The lagoon encompasses diverse geologic and climatic regions and it is an efficient sediment trap that accumulates clastic sediments from upland, interior, and oceanic sources. The semi-arid...
Mesoproterozoic graphite deposits, New Jersey Highlands: Geologic and stable isotopic evidence for possible algal origins
R.A. Volkert, Craig A. Johnson, Albert V. Tamashausky
2000, Canadian Journal of Earth Sciences (37) 1665-1675
Graphite deposits of Mesoproterozoic age are locally abundant in the eastern New Jersey Highlands, where they are hosted by sulphidic biotite–quartz–feldspar gneiss, metaquartzite, and anatectic pegmatite. Gneiss and metaquartzite represent a shallow marine shelf sequence of locally organic-rich sand and mud. Graphite from massive deposits within metaquartzite yielded δ13C values...
Climatic and biotic controls on annual carbon storage in Amazonian ecosystems
H. Tian, J. M. Melillo, D. W. Kicklighter, A. D. McGuire, J. Helfrich Iii, B. Moore III, C. J. Vorosmarty
2000, Global Ecology and Biogeography (9) 315-335
1 The role of undisturbed tropical land ecosystems in the global carbon budget is not well understood. It has been suggested that inter-annual climate variability can affect the capacity of these ecosystems to store carbon in the short term. In this paper, we use a transient version of the Terrestrial...
Results of the Imager for Mars Pathfinder windsock experiment
Robert Sullivan, Ronald Greeley, Michael Kraft, Gregory Wilson, Matthew P. Golombek, Kenneth E. Herkenhoff, James Murphy, Peter Smith
2000, Journal of Geophysical Research E: Planets (105) 24547-24562
The Imager for Mars Pathfinder (IMP) windsock experiment measured wind speeds at three heights within 1.2 m of the Martian surface during Pathfinder landed operations. These wind data allowed direct measurement of near-surface wind profiles on Mars for the first time, including determination of aerodynamic roughness length and wind friction...
Trophic ecology of largemouth bass and northern pike in allopatric and sympatric assemblages in northern boreal lakes
Craig A. Soupir, Michael L. Brown, Larry W. Kallemeyn
2000, Canadian Journal of Zoology (78) 1759-1766
Largemouth bass (Micropterus salmoides) and northern pike (Esox lucius) are top predators in the food chain in most aquatic environments that they occupy; however, limited information exists on species interactions in the northern reaches of largemouth bass distribution. We investigated the seasonal food habits of allopatric and sympatric assemblages of largemouth bass...
Gap analysis: Concepts, methods, and recent results
M.D. Jennings
2000, Landscape Ecology (15) 5-20
Rapid progress is being made in the conceptual, technical, and organizational requirements for generating synoptic multi-scale views of the earth's surface and its biological content. Using the spatially comprehensive data that are now available, researchers, land managers, and land-use planners can, for the first time, quantitatively place landscape units -...
10,000 Years of explosive eruptions of Merapi Volcano, Central Java: archaeological and modern implications
C. G. Newhall, S. Bronto, B. Alloway, N.G. Banks, I. Bahar, Del Marmol, R.D. Hadisantono, R. T. Holcomb, J. McGeehin, J.N. Miksic, M. Rubin, S.D. Sayudi, R. Sukhyar, Supriyati Andreastuti, R.I. Tilling, R. Torley, D. Trimble, A.D. Wirakusumah
2000, Journal of Volcanology and Geothermal Research (100) 9-50
Stratigraphy and radiocarbon dating of pyroclastic deposits at Merapi Volcano, Central Java, reveals ~10,000 years of explosive eruptions. Highlights include: (1) Construction of an Old Merapi stratovolcano to the height of the present cone or slightly higher. Our oldest age for an explosive eruption is 9630±60 14C y B.P.; construction...
Debris flow monitoring in the Acquabona watershed on the Dolomites (Italian Alps)
M. Berti, R. Genevois, R. LaHusen, A. Simoni, P.R. Tecca
2000, Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere (25) 707-715
In 1997 a field monitoring system was installed in Acquabona Creek in the Dolomites (Eastern Italian Alps) to observe the hydrologic conditions for debris flow occurrence and some dynamic properties of debris flow. The monitoring system consists of three remote stations: an upper one located at the head of...
Ecology and biology of paddlefish in North America: historical perspectives, management approaches, and research priorities
Cecil A. Jennings, Stephen J. Zigler
2000, Reviews in Fish Biology and Fisheries (10) 167-181
Paddlefish (Polyodon spathula, Polyodontidae)are large, mostly-riverine fish that once were abundant in medium- to large-sized river systems throughout much of the central United States. Concern for paddlefish populations has grown from a regional fisheries issue to one of national importance for the United States. In 1989, the U.S. Fish and...
