Weathering of the Rio Blanco quartz diorite, Luquillo Mountains, Puerto Rico: Coupling oxidation, dissolution, and fracturing
H.L. Buss, P.B. Sak, S.M. Webb, S.L. Brantley
2008, Geochimica et Cosmochimica Acta (72) 4488-4507
In the mountainous Rio Icacos watershed in northeastern Puerto Rico, quartz diorite bedrock weathers spheroidally, producing a 0.2-2 m thick zone of partially weathered rock layers (???2.5 cm thickness each) called rindlets, which form concentric layers around corestones. Spheroidal fracturing has been modeled to occur when a weathering reaction with...
Galileo observations of volcanic plumes on Io
P.E. Geissler, M.T. McMillan
2008, Icarus (197) 505-518
Io's volcanic plumes erupt in a dazzling variety of sizes, shapes, colors and opacities. In general, the plumes fall into two classes, representing distinct source gas temperatures. Most of the Galileo imaging observations were of the smaller, more numerous Prometheus-type plumes that are produced when hot flows of silicate lava...
Biogenic origin of coalbed gas in the northern Gulf of Mexico Coastal Plain, U.S.A
Peter D. Warwick, F. Clayton Breland Jr., Paul C. Hackley
2008, International Journal of Coal Geology (76) 119-137
New coal-gas exploration and production in northern Louisiana and south-central Mississippi, Gulf of Mexico Basin, is focused on the Wilcox Group (Paleocene–Eocene), where the depth to targeted subbituminous C to high volatile C bituminous coal beds ranges from 300 to 1680 m, and individual coal beds have a maximum thickness of...
Variability of geochemical properties in a microbially dominated coalbed gas system from the eastern margin of the Illinois Basin, USA
D. Strapoc, Maria Mastalerz, A. Schimmelmann, A. Drobniak, S. Hedges
2008, International Journal of Coal Geology (76) 98-110
This study outlines gas characteristics along the southeastern margins of the Illinois Basin and evaluates regional versus local gas variations in Seelyville and Springfield coal beds. Our findings suggest that high permeability and shallow (100-250??m) depths of these Indiana coals allowed inoculation with methanogenic microbial consortia, thus leading to widespread...
Geochemical controls of elevated arsenic concentrations in groundwater, Ester Dome, Fairbanks district, Alaska
P. L. Verplanck, S. H. Mueller, R.J. Goldfarb, D. Kirk Nordstrom, E. K. Youcha
2008, Chemical Geology (255) 160-172
Ester Dome, an upland area near Fairbanks, Alaska, was chosen for a detailed hydrogeochemical study because of the previously reported elevated arsenic in groundwater, and the presence of a large set of wells amenable to detailed sampling. Ester Dome lies within the Fairbanks...
Mercury and other element exposure to tree swallows (Tachycineta bicolor) nesting on Lostwood National Wildlife Refuge, North Dakota
T. W. Custer, Christine M. Custer, K. M. Johnson, D. J. Hoffman
2008, Environmental Pollution (155) 217-226
Elevated mercury concentrations in water were reported in the prairie wetlands at Lostwood National Wildlife Refuge, ND. In order to determine whether wildlife associated with these wetlands was exposed to and then accumulated higher mercury concentrations than wildlife living near more permanent wetlands (e.g. lakes), tree swallow (Tachycineta bicolor) eggs...
Anomalous cold in the Pangaean tropics
G.S. Soreghan, M. J. Soreghan, C.J. Poulsen, R.A. Young, C.F. Eble, D.E. Sweet, O.C. Davogustto
2008, Geology (36) 659-662
The late Paleozoic archives the greatest glaciation of the Phanerozoic. Whereas high-latitude Gondwanan strata preserve widespread evidence for continental ice, the Permo-Carboniferous tropics have long been considered analogous to today's: warm and shielded from the highlatitude cold. Here, we report on glacial and periglacial indicators that record episodes of freezing...
Combining MODIS and Landsat imagery to estimate and map boreal forest cover loss
P. Potapov, Matthew C. Hansen, S.V. Stehman, Thomas R. Loveland, K. Pittman
2008, Remote Sensing of Environment (112) 3708-3719
Estimation of forest cover change is important for boreal forests, one of the most extensive forested biomes, due to its unique role in global timber stock, carbon sequestration and deposition, and high vulnerability to the effects of global climate change. We used time-series data from the MODerate Resolution Imaging Spectroradiometer...
Species traits influence the genetic consequences of river fragmentation on two co-occurring redhorse (Moxostoma) species
S.M. Reid, C.C. Wilson, L.M. Carl, T.G. Zorn
2008, Canadian Journal of Fisheries and Aquatic Sciences (65) 1892-1904
We used microsatellite DNA markers to test whether fragmentation of the Trent River (Ontario, Canada) has reduced genetic diversity and increased genetic differentiation among populations of river redhorse (Moxostoma carinatum) and shorthead redhorse (Moxostoma macrolepidotum). Allelic richness of both species was significantly greater along the free-flowing Muskegon River (Michigan, USA)...
Trade-offs of predation and foraging explain sexual segregation in African buffalo
C.T. Hay, P.C. Cross, P.J. Funston
2008, Journal of Animal Ecology (77) 850-858
1. Many studies have investigated why males and females segregate spatially in sexually dimorphic species. These studies have focused primarily on temperate zone ungulates in areas lacking intact predator communities, and few have directly assessed predation rates in different social environments. 2. Data on the movement, social affiliation, mortality and...
Importance of agricultural landscapes to nesting burrowing owls in the Northern Great Plains, USA
M. Restani, J.M. Davies, W.E. Newton
2008, Landscape Ecology (23) 977-987
Anthropogenic habitat loss and fragmentation are the principle factors causing declines of grassland birds. Declines in burrowing owl (Athene cunicularia) populations have been extensive and have been linked to habitat loss, primarily the decline of black-tailed prairie dog (Cynomys ludovicianus) colonies. Development of habitat use models is a research priority...
Monitoring waterbird abundance in wetlands: The importance of controlling results for variation in water depth
F. Bolduc, A. D. Afton
2008, Ecological Modelling (216) 402-408
Wetland use by waterbirds is highly dependent on water depth, and depth requirements generally vary among species. Furthermore, water depth within wetlands often varies greatly over time due to unpredictable hydrological events, making comparisons of waterbird abundance among wetlands difficult as effects of habitat variables and water depth are confounded....
Geolocation of man-made reservoirs across terrains of varying complexity using GIS
D.M. Mixon, D.A. Kinner, R.F. Stallard, J.P.M. Syvitski
2008, Computers & Geosciences (34) 1184-1197
The Reservoir Sedimentation Survey Information System (RESIS) is one of the world's most comprehensive databases of reservoir sedimentation rates, comprising nearly 6000 surveys for 1819 reservoirs across the continental United States. Sediment surveys in the database date from 1904 to 1999, though more than 95% of surveys were entered prior...
Grazed riparian management and stream channel response in southeastern Minnesota (USA) streams
J.A. Magner, B. Vondracek, K.N. Brooks
2008, Environmental Management (42) 377-390
The U.S. Department of Agriculture-Natural Resources Conservation Service has recommended domestic cattle grazing exclusion from riparian corridors for decades. This recommendation was based on a belief that domestic cattle grazing would typically destroy stream bank vegetation and in-channel habitat. Continuous grazing (CG) has caused adverse environmental damage, but along cohesive-sediment...
DDE in sediments of the Palos Verdes shelf, California: In situ transformation rates and geochemical fate
R.P. Eganhouse, J. Pontolillo
2008, Environmental Science & Technology (42) 6392-6398
From 1947 to 1971 the world's largest manufacturer of DDT discharged process wastes into the sewers of Los Angeles County. Roughly 870-1450 t of DDT were released to the ocean off Palos Verdes, CA, a portion of which (???100 t) resides in sediments on the continental shelf and slope. The...
Cancellation of spurious arrivals in Green's function extraction and the generalized optical theorem
R. Snieder, K. Van Wijk, M. Haney, R. Calvert
2008, Physical Review E - Statistical, Nonlinear, and Soft Matter Physics (78)
The extraction of the Green's function by cross correlation of waves recorded at two receivers nowadays finds much application. We show that for an arbitrary small scatterer, the cross terms of scattered waves give an unphysical wave with an arrival time that is independent of the source position. This constitutes...
Wave climate, sediment supply and the depth of the sand-mud transition: A global survey
D.A. George, P.S. Hill
2008, Marine Geology (254) 121-128
The influences of wave climate and sediment supply on the depths of sand-mud transitions (hSMT) are investigated. Depths of sand-mud transitions (SMT) are based on published granulometric data from surface samples gathered from 14 sites in different wave-dominated coastal environments with fluvial input, including high energy (Columbia, Eel, Russian, San...
Egg rejection behavior in a population exposed to parasitism: Village Weavers on Hispaniola
A. Cruz, J.W. Prather, J. W. Wiley, P.F. Weaver
2008, Behavioral Ecology (19) 398-403
In contrast to African Village Weavers (Ploceus cucullatus) that are parasitized by Diederik Cuckoos (Chrysococcyx caprius), introduced weavers on Hispaniola existed without parasitism for at least 2 centuries until the arrival of the Shiny Cowbird (Molothrus bonariensis) in the 1970s. Cruz and Wiley (1989) found that Hispaniolan weavers had a...
Seasonal and diel movements of white sturgeon in the lower columbia river
M.J. Parsley, N.D. Popoff, B. K. Van Der Leeuw, C.D. Wright
2008, Transactions of the American Fisheries Society (137) 1007-1017
Continuous monitoring of the movements and depths used by white sturgeon Acipenser transmontanus with acoustic telemetry technologies in the lower Columbia River provided information on diel and seasonal migrations, local movements, and site fidelity. White sturgeon moved to shallower water at night and showed greater activity, inferred from rates of...
Body mass of prefledging Emperor Geese Chen canagica: Large-scale effects of interspecific densities and food availability
B.C. Lake, Joel A. Schmutz, M. S. Lindberg, Craig R. Ely, W.D. Eldridge, F.J. Broerman
2008, Ibis (150) 527-540
We studied body mass of prefledging Emperor Geese Chen canagica at three locations across the Yukon–Kuskokwim Delta, Alaska, during 1990–2004 to investigate whether large‐scale variation in body mass was related to interspecific competition for food. From 1990 to 2004, densities of Cackling Geese Branta hutchinsii minima more than doubled and were c. 2–5× greater than...
Modeling axisymmetric flow and transport
C.D. Langevin
2008, Ground Water (46) 579-590
Unmodified versions of common computer programs such as MODFLOW, MT3DMS, and SEAWAT that use Cartesian geometry can accurately simulate axially symmetric ground water flow and solute transport. Axisymmetric flow and transport are simulated by adjusting several input parameters to account for the increase in flow area with radial distance from...
Importance of unsaturated zone flow for simulating recharge in a humid climate
R. J. Hunt, David E. Prudic, J.F. Walker, Marilyn P. Anderson
2008, Ground Water (46) 551-560
Transient recharge to the water table is often not well understood or quantified. Two approaches for simulating transient recharge in a ground water flow model were investigated using the Trout Lake watershed in north-central Wisconsin: (1) a traditional approach of adding recharge directly to the water table and (2) routing...
Dispersal of Culex quinquefasciatus (Diptera: Culicidae) in a Hawaiian rain forest
D.A. Lapointe
2008, Journal of Medical Entomology (45) 600-609
Introduced mosquito-borne pathogens avian malaria (Plasmodium relictum Grassi and Feletti) and avian pox virus (Avipoxvirus) have been implicated in the past extinctions and declines of Hawaiian avifauna and remain significant obstacles to the recovery and restoration of endemic Hawaiian birds. Effective management of avian disease will require extensive mosquito control...
Inferences about ungulate population dynamics derived from age ratios
N.C. Harris, M. J. Kauffman, L. S. Mills
2008, Journal of Wildlife Management (72) 1143-1151
Age ratios (e.g., calf:cow for elk and fawn:doe for deer) are used regularly to monitor ungulate populations. However, it remains unclear what inferences are appropriate from this index because multiple vital rate changes can influence the observed ratio. We used modeling based on elk (Cervus elaphus) life-history to evaluate both...
Genetic characterization of Kenai brown bears (Ursus arctos): Microsatellite and mitochondrial DNA control region variation in brown bears of the Kenai Peninsula, south central Alaska
J.V. Jackson, Sandra L. Talbot, S. Farley
2008, Canadian Journal of Zoology (86) 756-764
We collected data from 20 biparentally inherited microsatellite loci, and nucleotide sequence from the maternally inherited mitochondrial DNA (mtDNA) control region, to determine levels of genetic variation of the brown bears (Ursus arctos L., 1758) of the Kenai Peninsula, south central Alaska. Nuclear genetic variation was similar to that observed...
