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University of Nebraska - Lincoln

United States Geological Survey: Staff Publications

2007

Articles 31 - 50 of 50

Full-Text Articles in Physical Sciences and Mathematics

Microsatellite Loci For Distinguishing Spotted Owls (Strix Occidentalis), Barred Owls (Strix Varia), And Their Hybrids, W. Chris Funk, Thomas D. Mullins, Eric D. Forsman, Susan M. Haig Jan 2007

Microsatellite Loci For Distinguishing Spotted Owls (Strix Occidentalis), Barred Owls (Strix Varia), And Their Hybrids, W. Chris Funk, Thomas D. Mullins, Eric D. Forsman, Susan M. Haig

United States Geological Survey: Staff Publications

We identified four diagnostic microsatellite loci that distinguish spotted owls (Strix occidentalis), barred owls (Strix varia), F1 hybrids and backcrosses. Thirty-four out of 52 loci tested (65.4%) successfully amplified, and four of these loci (11.8%) had allele sizes that did not overlap between spotted and barred owls. The probability of correctly identifying a backcross with these four loci is 0.875. Genotyping potential hybrid owls with these markers revealed that field identifications were often wrong. Given the difficulty of identifying hybrids in the field, these markers will be useful for hybrid identification, law enforcement and spotted …

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Possible Impacts Of Early-11th-, Middle-12th-, And Late-13th-Century Droughts On Western Native Americans And The Mississippian Cahokians, Larry V. Benson, Michael S. Berry, Edward A. Jolie, Jerry D. Spangler, David W. Stahle, Eugene M. Hattori Jan 2007

Possible Impacts Of Early-11th-, Middle-12th-, And Late-13th-Century Droughts On Western Native Americans And The Mississippian Cahokians, Larry V. Benson, Michael S. Berry, Edward A. Jolie, Jerry D. Spangler, David W. Stahle, Eugene M. Hattori

United States Geological Survey: Staff Publications

One or more of three intense and persistent droughts impacted some Native American cultures in the early-11th, middle-12th and late- 13th centuries, including the Anasazi, Fremont, Lovelock, and Mississippian (Cahokian) prehistorical cultures. Tree-ring-based reconstructions of precipitation and temperature indicate that warm drought periods occurred between AD 990 and 1060, AD 1135 and 1170, and AD 1276 and 1297. These droughts occurred during minima in the Pacific Decadal Oscillation and may have been associated with positive values of the Atlantic Multidecadal Oscillation. Each of the Native American cultures was supported, to a greater or lesser degree, by precipitation-dependent resources. Both the …

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Hydrologic Connectivity And The Contribution Of Stream Headwaters To Ecological Integrity At Regional Scales1, Mary C. Freeman, Catherine M. Pringle, C. Rhett Jackson Jan 2007

Hydrologic Connectivity And The Contribution Of Stream Headwaters To Ecological Integrity At Regional Scales1, Mary C. Freeman, Catherine M. Pringle, C. Rhett Jackson

United States Geological Survey: Staff Publications

Cumulatively, headwater streams contribute to maintaining hydrologic connectivity and ecosystem integrity at regional scales. Hydrologic connectivity is the water-mediated transport of matter, energy and organisms within or between elements of the hydrologic cycle. Headwater streams compose over two-thirds of total stream length in a typical river drainage and directly connect the upland and riparian landscape to the rest of the stream ecosystem. Altering headwater streams, e.g., by channelization, diversion through pipes, impoundment and burial, modifies fluxes between uplands and downstream river segments and eliminates distinctive habitats. The large-scale ecological effects of altering headwaters are amplified by land uses that alter …

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Loess Deposits, Origins And Properties, Daniel R. Muhs Jan 2007

Loess Deposits, Origins And Properties, Daniel R. Muhs

United States Geological Survey: Staff Publications

Loess is an eolian (windblown) sediment that is an important archive of Quaternary climate changes. It may provide one of the most complete terrestrial records of interglacial–glacial cycles. Loess is unusual as a record of Quaternary climate change because it is one of the few sediments that is deposited directly from the atmosphere. Thus, it is a geologic deposit that contains a record of atmospheric circulation and can be used to reconstruct synoptic-scale paleoclimatology. Loess is also unusual in that it can be dated directly using ‘trapped electron’ or luminescence methods that require only the sediment itself. Commonly, loess deposits …

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Sexual Selection Drives Speciation In An Amazonian Frog, Kathryn E. Boul, W. Chris Funk, Catherine R. Darst, David C. Cannatella, Michael J. Ryan Jan 2007

Sexual Selection Drives Speciation In An Amazonian Frog, Kathryn E. Boul, W. Chris Funk, Catherine R. Darst, David C. Cannatella, Michael J. Ryan

United States Geological Survey: Staff Publications

One proposed mechanism of speciation is divergent sexual selection, whereby divergence in female preferences and male signals results in behavioural isolation. Despite the appeal of this hypothesis, evidence for it remains inconclusive. Here, we present several lines of evidence that sexual selection is driving behavioural isolation and speciation among populations of an Amazonian frog (Physalaemus petersi). First, sexual selection has promoted divergence in male mating calls and female preferences for calls between neighbouring populations, resulting in strong behavioural isolation. Second, phylogenetic analysis indicates that populations have become fixed for alternative call types several times throughout the species’ range, …

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An Evaluation Of Selenium Concentrations In Water, Sediment, Invertebrates, And Fish From The Solomon River Basin, Thomas W. May, James F. Fairchild, Jim D. Petty, Michael J. Walther, Jeff Lucero, Mike Delvaux, Jill Manring, M. Armbruster Jan 2007

An Evaluation Of Selenium Concentrations In Water, Sediment, Invertebrates, And Fish From The Solomon River Basin, Thomas W. May, James F. Fairchild, Jim D. Petty, Michael J. Walther, Jeff Lucero, Mike Delvaux, Jill Manring, M. Armbruster

United States Geological Survey: Staff Publications

The Solomon River Basin is located in north-central Kansas in an area underlain by marine geologic shales. Selenium is an indigenous constituent of these shales and is readily leached into the surrounding groundwater. Portions of the Basin are irrigated primarily through the pumping of selenium-contaminated groundwater from wells onto fields in agricultural production. Water, sediment, macro-invertebrates, and fish were collected from various sites in the Basin in 1998 and analyzed for selenium. Selenium concentrations were analyzed spatially and temporally and compared to reported selenium toxic effect thresholds for specific ecosystem components: water, sediments, food-chain organisms, and whole-body fish. A selenium …

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Identifying Fecal Sources In A Selected Catchment Reach Using Multiple Source-Tracking Tools, Jason R. Vogel, Donald M. Stoeckel, Regina Lamendella, Ronald B. Zelt, Jorge W. Santo Domingo, Steven R. Walker, Daniel B. Oerther Jan 2007

Identifying Fecal Sources In A Selected Catchment Reach Using Multiple Source-Tracking Tools, Jason R. Vogel, Donald M. Stoeckel, Regina Lamendella, Ronald B. Zelt, Jorge W. Santo Domingo, Steven R. Walker, Daniel B. Oerther

United States Geological Survey: Staff Publications

Given known limitations of current microbial source-tracking (MST) tools, emphasis on small, simple study areas may enhance interpretations of fecal contamination sources in streams. In this study, three MST tools—Escherichia coli repetitive element polymerase chain reaction (rep-PCR), coliphage typing, and Bacteroidales 16S rDNA host-associated markers—were evaluated in a selected reach of Plum Creek in south-central Nebraska. Water-quality samples were collected from six sites. One reach was selected for MST evaluation based on observed patterns of E. coli contamination. Despite high E. coli concentrations, coliphages were detected only once among water samples, precluding their use as a MST tool in …

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Factors Influencing Movement Probabilities Of Big Brown Bats (Eptesicus Fuscus) In Buildings, Laura E. Ellison, Thomas J. O’Shea, Daniel J. Neubaum, Richard Bowen Jan 2007

Factors Influencing Movement Probabilities Of Big Brown Bats (Eptesicus Fuscus) In Buildings, Laura E. Ellison, Thomas J. O’Shea, Daniel J. Neubaum, Richard Bowen

United States Geological Survey: Staff Publications

We investigated movements of female big brown bats (Eptesicus fuscus) roosting in maternity colonies in buildings in Fort Collins, Colorado (USA), during the summers of 2002, 2003, and 2005. This behavior can be of public health concern where bats that may carry diseases (e.g., rabies) move among buildings occupied by people. We used passive integrated transponders (PIT tags) to mark individual bats and hoop PIT readers at emergence points to passively monitor the use of building roosts by marked adult females on a daily basis during the lactation phase of reproduction. Multi-strata models were used to examine movements …

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Amphibians And Disease: Implications For Conservation In The Greater Yellowstone Ecosystem, Paul Stephen Corn Jan 2007

Amphibians And Disease: Implications For Conservation In The Greater Yellowstone Ecosystem, Paul Stephen Corn

United States Geological Survey: Staff Publications

The decline of amphibian populations is a worldwide phenomenon that has received increasing attention since about 1990. In 2004, the World Conservation Union’s global amphibian assessment concluded that 48% of the world’s 5,743 described amphibian species were in decline, with 32% considered threatened (Stuart et al. 2004). Amphibian declines are a significant issue in the western United States, where all native species of frogs in the genus Rana and many toads in the genus Bufo are at risk, particularly those that inhabit mountainous areas (Corn 2003a,b; Bradford 2005). As is true for most of the cold and dry Rocky Mountains, …

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Late Quaternary Paleoenvironments Of An Ephemeral Wetland In North Dakota, Usa: Relative Interactions Of Ground-Water Hydrology And Climate Change, Catherine H. Yansa, Walter E. Dean, Edward C. Murphy Jan 2007

Late Quaternary Paleoenvironments Of An Ephemeral Wetland In North Dakota, Usa: Relative Interactions Of Ground-Water Hydrology And Climate Change, Catherine H. Yansa, Walter E. Dean, Edward C. Murphy

United States Geological Survey: Staff Publications

This study of fossils (pollen, plant macrofossils, stomata and fish) and sediments (lithostratigraphy and geochemistry) from the Wendel site in North Dakota, USA, emphasizes the importance of considering ground-water hydrology when deciphering paleoclimate signals from lakes in postglacial landscapes. The Wendel site was a paleolake from about 11,500 14C yr BP to 11,100 14C yr BP. Afterwards, the lake-level lowered until it became a prairie marsh by 9,300 14C yr BP and finally, at 8,500 14C yr BP, an ephemeral wetland as it is today. Meanwhile, the vegetation changed from a white spruce parkland (11,500 to …

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Source Parameters Of A M4.8 And Its Accompanying Repeating Earthquakes Off Kamaishi, Ne Japan: Implications For The Hierarchical Structure Of Asperities And Earthquake Cycle, Naoki Uchida, Toru Matsuzawa, William L. Ellsworth, Kazutoshi Imanishi, Tomomi Okada, Akira Hasegawa Jan 2007

Source Parameters Of A M4.8 And Its Accompanying Repeating Earthquakes Off Kamaishi, Ne Japan: Implications For The Hierarchical Structure Of Asperities And Earthquake Cycle, Naoki Uchida, Toru Matsuzawa, William L. Ellsworth, Kazutoshi Imanishi, Tomomi Okada, Akira Hasegawa

United States Geological Survey: Staff Publications

We determine the source parameters of a M4.9 ± 0.1 'characteristic earthquake’ sequence and its accompanying microearthquakes at ~50 km depth on the subduction plate boundary offshore of Kamaishi, NE Japan. The microearthquakes tend to occur more frequently in the latter half of the recurrence intervals of the M4.9 ± 0.1 events. Our results show that the microearthquakes are repeating events and they are located not only around but also within the slip area for the 2001 M4.8 event. From the hierarchical structure of slip areas and smaller stress drops for the microearthquakes compared to the M4.8 event, we infer …

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Structure And Properties Of The San Andreas Fault In Central California: Recent Results From The Safod Experiment, Stephen Hickman, Mark D. Zoback, William Ellsworth, Naomi Boness, Peter Malin, Steven Roecker, Clifford Thurber Jan 2007

Structure And Properties Of The San Andreas Fault In Central California: Recent Results From The Safod Experiment, Stephen Hickman, Mark D. Zoback, William Ellsworth, Naomi Boness, Peter Malin, Steven Roecker, Clifford Thurber

United States Geological Survey: Staff Publications

The San Andreas Fault Observatory at Depth (SAFOD) is a 3.2-km-deep borehole observatory drilled into the San Andreas fault zone at seismogenic depths to study directly the physical and chemical processes controlling faulting and earthquake generation. SAFOD forms one component of EarthScope, a major Earth Science facility program of the U.S. National Science Foundation; the other two funded components are U.S. Array, a continental-scale seismic network, and the Plate Boundry Observatory, an extensive network of GOS receivers and strainmeters deployed acorss the western U.S. SAFOD is being conducted in collaboration with the U.S. Geological Survey and the International Continental Scientific …

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Aquifer-Scale Controls On The Distribution Of Nitrate And Ammonium In Ground Water Near La Pine, Oregon, Usa, Stephen R. Hinkle, J. K. Böhlke, John H. Duff, David S. Morgan, Rodney J. Weick Jan 2007

Aquifer-Scale Controls On The Distribution Of Nitrate And Ammonium In Ground Water Near La Pine, Oregon, Usa, Stephen R. Hinkle, J. K. Böhlke, John H. Duff, David S. Morgan, Rodney J. Weick

United States Geological Survey: Staff Publications

Geochemical and isotopic tools were applied at aquifer, transect, and subtransect scales to provide a framework for understanding sources, transport, and fate of dissolved inorganic N in a sandy aquifer near La Pine, Oregon. NO3 is a common contaminant in shallow ground water in this area, whereas high concentrations of NH4– N (up to 39 mg/L) are present in deep ground water. N concentrations, N/Cl ratios, tracer- based apparent ground-water ages, N isotope data, and hydraulic gradients indicate that septic tank effluent is the primary source of NO3. N isotope data, N/Cl and N/C relations, …

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Factors Influencing Ground-Water Recharge In The Eastern United States, Bernard T. Nolan, Richard W. Healy, Patrick E. Taber, Kimberlie Perkins, Kerie J. Hitt, David M. Wolock Jan 2007

Factors Influencing Ground-Water Recharge In The Eastern United States, Bernard T. Nolan, Richard W. Healy, Patrick E. Taber, Kimberlie Perkins, Kerie J. Hitt, David M. Wolock

United States Geological Survey: Staff Publications

Ground-water recharge estimates for selected locations in the eastern half of the United States were obtained by Darcian and chloride-tracer methods and compared using statistical analyses. Recharge estimates derived from unsaturated-zone (RUZC) and saturated-zone (RSZC) chloride mass balance methods are less variable (interquartile ranges or IQRs are 9.5 and 16.1 cm/yr, respectively) and more strongly correlated with climatic, hydrologic, land use, and sediment variables than Darcian estimates (IQR = 22.8 cm/yr). The unit-gradient Darcian estimates are a nonlinear function of moisture content and also reflect the uncertainty of pedotransfer functions used to estimate hydraulic parameters. Significance …

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Dune Fields: Mid-Latitudes, J. Sun, Daniel R. Muhs Jan 2007

Dune Fields: Mid-Latitudes, J. Sun, Daniel R. Muhs

United States Geological Survey: Staff Publications

Large dune fields, or sand seas, are landscapes often thought to be found only in deserts beneath the great, subtropical high-pressure zones, where subsiding air suppresses rainfall. Dune fields are also quite common in mid-latitude regions, to the north and south of subtropical deserts (Fig. 1). Two major characteristics distinguish many mid-latitude dune fields from the sand seas of lower latitudes. One difference is that many of those in mid-latitudes are in semiarid, rather than arid climates, and therefore are not presently active. In this article, ‘active’ refers to eolian sand bodies that are not covered with vegetation, and where …

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Loess Sedimentation In Tibet: Provenance, Processes, And Link With Quaternary Glaciations, Jimin Sun, Sheng-Hua Li, Daniel R. Muhs, Bo Li Jan 2007

Loess Sedimentation In Tibet: Provenance, Processes, And Link With Quaternary Glaciations, Jimin Sun, Sheng-Hua Li, Daniel R. Muhs, Bo Li

United States Geological Survey: Staff Publications

Well-preserved loess deposits are found on the foothills of mountains along the middle reaches of the Yarlung Zangbo River in southern Tibet. Optically stimulated luminescence (OSL) dating is used to determine loess ages by applying the single-aliquot regeneration technique. Geochemical, mineralogical, and granulometric measurements were carried out to allow a comparison between loess from Tibet and the Chinese Loess Plateau. Our results demonstrate that (i) the loess deposits have a basal age of 13–11 ka, suggesting they accumulated after the last deglaciation, (ii) loess in southern Tibet has a ‘‘glacial’’ origin, resulting from eolian sorting of glaciofluvial outwash deposits from …

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Comparison Of Local- To Regional-Scale Estimates Of Ground-Water Recharge In Minnesota, Usa, Geoffrey N. Delin, Richard W. Healy, David L. Lorenz, John R. Nimmo Jan 2007

Comparison Of Local- To Regional-Scale Estimates Of Ground-Water Recharge In Minnesota, Usa, Geoffrey N. Delin, Richard W. Healy, David L. Lorenz, John R. Nimmo

United States Geological Survey: Staff Publications

Regional ground-water recharge estimates for Minnesota were compared to estimates made on the basis of four local- and basin-scale methods. Three local-scale methods (unsaturated-zone water balance, water-table fluctuations (WTF) using three approaches, and age dating of ground water) yielded point estimates of recharge that represent spatial scales from about 1 to about 1000 m2. A fourth method (RORA, a basin-scale analysis of streamflow records using a recession-curve-displacement technique) yielded recharge estimates at a scale of 10–1000s of km2. The RORA basin-scale recharge estimates were regionalized to estimate recharge for the entire State of Minnesota on the …

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Passive Aerobic Treatment Of Net-Alkaline, Iron-Laden Drainage From A Flooded Underground Anthracite Mine, Pennsylvania, Usa, Charles A. Cravotta Iii Jan 2007

Passive Aerobic Treatment Of Net-Alkaline, Iron-Laden Drainage From A Flooded Underground Anthracite Mine, Pennsylvania, Usa, Charles A. Cravotta Iii

United States Geological Survey: Staff Publications

This report evaluates the results of a continuous 4.5-day laboratory aeration experiment and the first year of passive, aerobic treatment of abandoned mine drainage (AMD) from a typical flooded underground anthracite mine in eastern Pennsylvania, USA. During 1991–2006, the AMD source, locally known as the Otto Discharge, had flows from 20 to 270 L/s (median 92 L/s) and water quality that was consistently suboxic (median 0.9 mg/L O2) and circumneutral (pH ~ 6.0; net alkalinity >10) with moderate concentrations of dissolved iron and manganese and low concentrations of dissolved aluminum (medians of 11, 2.2, and <0.2 mg/L, respectively). In 2001, the laboratory aeration experiment demonstrated rapid oxidation of ferrous iron (Fe2+) without …

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Evaluation And Comparison Of Gross Primary Production Estimates For The Northern Great Plains Grasslands, Li Zhang, Bruce K. Wylie, Thomas Loveland, Eugene A. Fosnight, Larry L. Tieszen, Lei Ji, Tagir G. Gilmanov Jan 2007

Evaluation And Comparison Of Gross Primary Production Estimates For The Northern Great Plains Grasslands, Li Zhang, Bruce K. Wylie, Thomas Loveland, Eugene A. Fosnight, Larry L. Tieszen, Lei Ji, Tagir G. Gilmanov

United States Geological Survey: Staff Publications

Two spatially-explicit estimates of gross primary production (GPP) are available for the Northern Great Plains. An empirical piecewise regression (PWR) GPP model was developed from flux tower measurements to map carbon flux across the region. The Moderate Resolution Imaging Spectrometer (MODIS) GPP model is a process-based model that uses flux tower data to calibrate its parameters. Verification and comparison of the regional PWR GPP and the global MODIS GPP are important for the modeling of grassland carbon flux. This study compared GPP estimates from PWR and MODIS models with five towers in the grasslands. Among them, PWR GPP and MODIS …

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Conservation Genetics Of Snowy Plovers (Charadrius Alexandrinus) In The Western Hemisphere: Population Genetic Structure And Delineation Of Subspecies, W. Chris Funk, Thomas D. Mullins, Susan M. Haig Jan 2007

Conservation Genetics Of Snowy Plovers (Charadrius Alexandrinus) In The Western Hemisphere: Population Genetic Structure And Delineation Of Subspecies, W. Chris Funk, Thomas D. Mullins, Susan M. Haig

United States Geological Survey: Staff Publications

We examined the genetic structure of snowy plovers (Charadrius alexandrinus) in North America, the Caribbean, and the west coast of South America to quantify variation within and among breeding areas and to test the validity of three previously recognized subspecies. Sequences (676 bp) from domains I and II of the mitochondrial control region were analyzed for 166 snowy plovers from 20 breeding areas. Variation was also examined at 10 microsatellite loci for 144 snowy plovers from 14 breeding areas. The mtDNA and microsatellite data provided strong evidence that the Puerto Rican breeding group is genetically divergent from sites …

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