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Articles 1021 - 1050 of 1402

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

A Loess–Paleosol Record Of Climate And Glacial History Over The Past Two Glacial–Interglacial Cycles (~150 Ka), Southern Jackson Hole, Wyoming, Kenneth L. Pierce, Daniel R. Muhs, Maynard A. Fosberg, Shannon A. Mahan, Joseph G. Rosenbaum, Joseph M. Licciardi, Milan J. Pavich Jan 2011

A Loess–Paleosol Record Of Climate And Glacial History Over The Past Two Glacial–Interglacial Cycles (~150 Ka), Southern Jackson Hole, Wyoming, Kenneth L. Pierce, Daniel R. Muhs, Maynard A. Fosberg, Shannon A. Mahan, Joseph G. Rosenbaum, Joseph M. Licciardi, Milan J. Pavich

United States Geological Survey: Staff Publications

Loess accumulated on a Bull Lake outwash terrace of Marine Oxygen Isotope Stage 6 (MIS 6) age in southern Jackson Hole, Wyoming. The 9 m section displays eight intervals of loess deposition (Loess 1 to Loess 8, oldest), each followed by soil development. Our age-depth model is constrained by thermoluminescence, meteoric 10Be accumulation in soils, and cosmogenic 10Be surface exposure ages. We use particle size, geochemical, mineral-magnetic, and clay mineralogical data to interpret loess sources and pedogenesis. Deposition of MIS 6 loess was followed by a tripartite soil/thin loess complex (Soils 8, 7, and 6) apparently re!ecting the …


Quantifying Canal Leakage Rates Using A Mass-Balance Approach And Heat-Based Hydraulic Conductivity Estimates In Selected Irrigation Canals, Western Nebraska, 2007 Through 2009, Christopher M. Hobza, Michael J. Andersen Dec 2010

Quantifying Canal Leakage Rates Using A Mass-Balance Approach And Heat-Based Hydraulic Conductivity Estimates In Selected Irrigation Canals, Western Nebraska, 2007 Through 2009, Christopher M. Hobza, Michael J. Andersen

United States Geological Survey: Water Reports and Publications

The water supply in areas of the North Platte River Basin in the Nebraska Panhandle has been designated as fully appropriated or overappropriated by the Nebraska Department of Natural Resources (NDNR). Enacted legislation (Legislative Bill 962) requires the North Platte Natural Resources District (NPNRD) and the NDNR to develop an Integrated Management Plan (IMP) to balance groundwater and surface-water supply and demand in the NPNRD. A clear understanding of the groundwater and surface-water systems is critical for the development of a successful IMP. The primary source of groundwater recharge in parts of the NPNRD is from irrigation canal leakage. Because …


Invasive Species And Climate Change, Invasive Species Advisory Committee Dec 2010

Invasive Species And Climate Change, Invasive Species Advisory Committee

National Invasive Species Council

ISSUE

Climate change interacts with and can often amplify the negative impacts of invasive species. These interactions are not fully appreciated or understood. They can result in threats to critical ecosystem functions on which our food system and other essential provisions and services depend as well as increase threats to human health. The Invasive Species Advisory Committee to the National Invasive Species Council recognizes the Administration’s commitment to dealing proactively with global climate change. However, unless we recognize and act on the impact of climate change and its interaction with ecosystems and invasive species, we will fall further behind in …


Propagating And Non-Propagating Intraseasonal Oscillations In The Tropical Atmosphere: Their Vertical And Horizontal Structures And Developing Mechanisms, Zhaoning Liang Dec 2010

Propagating And Non-Propagating Intraseasonal Oscillations In The Tropical Atmosphere: Their Vertical And Horizontal Structures And Developing Mechanisms, Zhaoning Liang

School of Natural Resources: Dissertations, Theses, and Student Research

A fixed beamformer is proposed and designed to identify source regions of Intra-Seasonal Oscillations (ISO) in the tropical atmosphere. After tested by simulations of single and complex sources of waves, the fixed beamformer is applied to the ECMWF interpolated data grids to detect and identify source regions of the ISO in the tropical Indian and Pacific Ocean region. Results show that the fixed beamforming technique can uniquely identify the source region of the ISO, the source regions of all major ISO in the tropical Indian and western equatorial Pacific region from 1974 to 2002 have been identified.

Examinations of ISO …


The Effect Of Enso On Nebraska Winter Snowfall, Jonathan Burnham Dec 2010

The Effect Of Enso On Nebraska Winter Snowfall, Jonathan Burnham

Department of Environmental Studies: Undergraduate Student Theses

No abstract provided.


Simulation Of Groundwater Flow And Effects Of Groundwater Irrigation On Stream Base Flow In The Elkhorn And Loup River Basins, Nebraska, 1895-2055: Phase Two, Jennifer S. Stanton, Steven M. Peterson, Michael N. Fienen Oct 2010

Simulation Of Groundwater Flow And Effects Of Groundwater Irrigation On Stream Base Flow In The Elkhorn And Loup River Basins, Nebraska, 1895-2055: Phase Two, Jennifer S. Stanton, Steven M. Peterson, Michael N. Fienen

United States Geological Survey: Water Reports and Publications

Regional groundwater-flow simulations for a 30,000-square-mile area of the High Plains aquifer, referred to collectively as the Elkhorn-Loup Model, were developed to predict the effects of groundwater irrigation on stream base flow in the Elkhorn and Loup River Basins, Nebraska. Simulations described the stream-aquifer system from predevelopment through 2005 [including predevelopment (pre-1895), early development (1895–1940), and historical development (1940 through 2005) conditions] and future hypothetical development conditions (2006 through 2033 or 2055). Predicted changes to stream base flow that resulted from simulated changes to groundwater irrigation will aid development of long-term strategies for management of hydrologically connected water supplies.

The …


Droughtscape, Fall 2010, Kelly Smith Oct 2010

Droughtscape, Fall 2010, Kelly Smith

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

CDC Issues Drought Guidance for Public Health

La Niña May Intensify Drought in South

Recent Workshops and Meetings

East Feels Impacts as Heat Intensifies Drought

New Products

Nicole Wall Co-Facilitates Republican River Basin Task Force

NDMC Climatologist on Ethiopia Team


Hydrogeomorphic Segments And Hydraulic Microhabitats Of The Niobrara River, Nebraska, With Special Emphasis On The Niobrara National Scenic River, Jason S. Alexander, Ronald B. Zelt, Nathaniel J. Schaepe Aug 2010

Hydrogeomorphic Segments And Hydraulic Microhabitats Of The Niobrara River, Nebraska, With Special Emphasis On The Niobrara National Scenic River, Jason S. Alexander, Ronald B. Zelt, Nathaniel J. Schaepe

United States Geological Survey: Water Reports and Publications

The Niobrara River is an ecologically and economically important resource in Nebraska. The Nebraska Department of Natural Resources’ recent designation of the hydraulically connected surface- and groundwater resources of the Niobrara River Basin as “fully appropriated” has emphasized the importance of understanding linkages between the physical and ecological dynamics of the Niobrara River so it can be sustainably managed. In cooperation with the Nebraska Game and Parks Commission, the United States Geological Survey USGS) investigated the hydrogeomorphic and hydraulic attributes of the Niobrara River in northern Nebraska. This report presents the results of an analysis of hydrogeomorphic segments and hydraulic …


An Intercomparison Of Regional Atmospheric Circulation And The Melt Season Loss Of Arctic Snow Cover And Sea Ice Extent Across The Land–Ocean Boundary, Angela C. Bliss Aug 2010

An Intercomparison Of Regional Atmospheric Circulation And The Melt Season Loss Of Arctic Snow Cover And Sea Ice Extent Across The Land–Ocean Boundary, Angela C. Bliss

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

This study is designed to compare the monthly continental snow cover and sea ice extent loss in the Arctic with regional atmospheric conditions including: mean sea level pressure, 925 hPa air temperature, and mean wind direction among others during the melt season (March-August) over the 29-year study period 1979-2007. Little research has gone into studying the concurrent variations in the annual loss of continental snow cover and sea ice extent across the land-ocean boundary, since these data are largely stored in incompatible formats. However, the analysis of these data, averaged spatially over three autonomous study regions located in Siberia, North …


The Toll Of Toxics: Investigating Environmental Contaminants, Donald Sparling, Barnett A. Rattner, John S. Barclay Jul 2010

The Toll Of Toxics: Investigating Environmental Contaminants, Donald Sparling, Barnett A. Rattner, John S. Barclay

United States Geological Survey: Staff Publications

Two recent events [the Deepwater Horizon oil spill and the Asarco settlement] bring to the fore the work of wildlife toxicologists. Focusing on amphibians, reptiles, birds, and mammals, wildlife toxicology is a component of ecotoxicology--the study of toxic effects caused by natural or synthetic pollutants on living organisms and other constituents of ecosystems (Truhaut 1977). Now a distinct discipline within the wildlife profession-practiced by members of The Wildlife Society's own Wildlife Toxicology Working Group, among others-wildlife toxicology has become increasingly important as human populations and industry have spread, causing contaminants to multiply.

Emerging Environmental Contaminants (EECs) include an array of …


Droughtscape, Summer 2010, Kelly Smith Jul 2010

Droughtscape, Summer 2010, Kelly Smith

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

Upcoming Workshops

Mild Drought Season Likely to Persist

Drought Impacts Intensify in Upper Midwest

Visiting Scientists

North Carolina Takes Drought Monitor Seriously

International Work- Murcia, Spain, June


Marine Bioinvasions And Climate Change, James T. Carlton, Sandra C. Lindstrom, Celia M. Smith, Jennifer E. Smith Jun 2010

Marine Bioinvasions And Climate Change, James T. Carlton, Sandra C. Lindstrom, Celia M. Smith, Jennifer E. Smith

National Invasive Species Council

BACKGROUND

Invasive species are second only to habitat destruction as the greatest cause of species endangerment and global biodiversity loss. Invasive species can cause severe and permanent damage to the ecosystems they invade. Consequences of invasion include competition with or predation upon native species, hybridization, carrying or supporting harmful pathogens and parasites that may affect wildlife and human health, disturbing ecosystem function through alteration of food webs and nutrient recycling rates, acting as ecosystem engineers and altering habitat structure, and degradation of the aesthetic quality of our natural resources. In many cases we may not fully know the native animals …


Mississippi Canyon 252 Incident Nrda Tier 1 For Deepwater Communities, Gregory Boland, Gary Brewer, Erik Cordes, Amanda Demopoulos, Chuek Fisher, Chris German, Ken Sulak May 2010

Mississippi Canyon 252 Incident Nrda Tier 1 For Deepwater Communities, Gregory Boland, Gary Brewer, Erik Cordes, Amanda Demopoulos, Chuek Fisher, Chris German, Ken Sulak

United States Geological Survey: Staff Publications

The northern Gulf of Mexico (GOM) is geologically diverse basin, described as the most complex continental slope region in the world. Regional topography of the slope consists of basins, knolls, ridges, and mounds derived from the dynamic adjustments of salt and the introduction of large volumes of sediment over long time scales. More than 99% of the sea floor in the GOM consists of soft sediment made up of various mixtures of primarily silt and clay. These wide-spread soft bottom communities are described in reports from major MMS studies by Gallaway et al. (1998) and Rowe and Kennicutt (2009). Relative …


Establishment And Partial Characterization Of A Cell Line From Burbot Lota Lota Maculosa: Susceptibility To Ihnv, Ipnv And Vhsv, Mark P. Polinski, John D. Drennan, William N. Batts, Susan C. Ireland, Kenneth D. Cain May 2010

Establishment And Partial Characterization Of A Cell Line From Burbot Lota Lota Maculosa: Susceptibility To Ihnv, Ipnv And Vhsv, Mark P. Polinski, John D. Drennan, William N. Batts, Susan C. Ireland, Kenneth D. Cain

United States Geological Survey: Staff Publications

This study describes the development and partial characterization of a continuous fibroblastic-like cell line (BEF-1) developed from late stage embryos of North American burbot Lota lota maculosa. This cell line has been maintained for over 5 yr and 100 passages in vitro. Cells were cultured using Eagle’s minimum essential medium with Earle’s salts (MEM) supplemented with GlutaMAX ™, and 10% fetal bovine serum (FBS), pH 7.4. The addition of penicillin-streptomycinneomycin (PSN) antibiotic mixture (0.05, 0.05, 0.1 mg ml–1, respectively) did not negatively influence cell replication; however, the antimycotic Fungizone™ (2.5 μg ml–1, amphotericin B) caused cell rounding and …


Influence Of Canopy Cover, Nutrients, And Season On Stoichiometric Variation Of Epilithon In Neotropical Streams., Tyler J. Kohler Apr 2010

Influence Of Canopy Cover, Nutrients, And Season On Stoichiometric Variation Of Epilithon In Neotropical Streams., Tyler J. Kohler

School of Natural Resources: Dissertations, Theses, and Student Research

Light and nutrient availability are strong factors determining the nutrient composition of epilithon in temperate stream ecosystems. However, little work has been performed regarding this association in tropical streams. In our study, we investigated 1) how gradients of canopy cover and nutrients and 2) wet/dry seasonality influence epilithon standing stocks and nutrient quality. We surveyed 18 stream locations within six watersheds that varied in nutrient and light conditions during both the wet and dry seasons on the island of Trinidad to test these questions. Additionally, we sampled four stream reaches bimonthly for three years, thinning the canopy of two of …


Droughtscape, Spring 2010, Kelly Smith Apr 2010

Droughtscape, Spring 2010, Kelly Smith

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

NDMC and NC Drought Council Team Up

Drought to Intensify in Northwest and Hawaii

International Work

Impacts Recorded in Hawaii and Western States

U.S. Drought Monitor Archives Enhanced

Low-Water Impact Surveys Completed

K-12 Drought Outreach


Minimum Riparian Buffer Width For Maintaining Water Quality And Habitat Along Stevens Creek, Sammi Bray Apr 2010

Minimum Riparian Buffer Width For Maintaining Water Quality And Habitat Along Stevens Creek, Sammi Bray

Department of Environmental Studies: Undergraduate Student Theses

ABSTRACT Riparian buffer zones are important sites of biodiversity, sediment trapping, pollutant removal, and hydrologic regulation that have significant implications for both people and wildlife. Urbanization’s influence on and need for adequate water quality increases the need for careful planning in regards to riparian areas. Wildlife are key components in the ecosystem functions of riparian zones and require consideration in peri-urban planning as well. This study reviews relevant literature to determine the recommended minimum riparian buffer width for maintaining water quality and habitat along Stevens Creek in Lincoln, Nebraska. Only sources that listed a specific purpose related to water quality …


Effects Of Drought On Avian Community Structure, Thomas P. Albright, Anna M. Pidgeon, Chadwick D. Rittenhouse, Murray K. Clayton, Curtis H. Flather, Patrick D. Culbert, Brian D. Wardlows, Volker C. Radeloff Jan 2010

Effects Of Drought On Avian Community Structure, Thomas P. Albright, Anna M. Pidgeon, Chadwick D. Rittenhouse, Murray K. Clayton, Curtis H. Flather, Patrick D. Culbert, Brian D. Wardlows, Volker C. Radeloff

National Drought Mitigation Center: Faculty Publications

Droughts are expected to become more frequent under global climate change. Avifauna depend on precipitation for hydration, cover, and food. While there are indications that avian communities respond negatively to drought, little is known about the response of birds with differing functional and behavioral traits, what time periods and indicators of drought are most relevant, or how response varies geographically at broad spatial scales. Our goals were thus to determine (1) how avian abundance and species richness are related to drought, (2) whether community variations are more related to vegetation vigor or precipitation deviations and at what time periods relationships …


Geochemical And Mineralogical Evidence For Sahara And Sahel Dust Additions To Quaternary Soils On Lanzarote, Eastern Canary Islands, Spain, Daniel R. Muhs, James Budahn, Gary Skipp, Joseph M. Prospero, Deanna Patterson, E. Arthur Bettis Iii Jan 2010

Geochemical And Mineralogical Evidence For Sahara And Sahel Dust Additions To Quaternary Soils On Lanzarote, Eastern Canary Islands, Spain, Daniel R. Muhs, James Budahn, Gary Skipp, Joseph M. Prospero, Deanna Patterson, E. Arthur Bettis Iii

United States Geological Survey: Staff Publications

Africa is the most important source of dust in the world today, and dust storms are frequent on the nearby Canary Islands. Previous workers have inferred that the Sahara is the most important source of dust to Canary Islands soils, with little contribution from the Sahel region. Soils overlying a late Quaternary basalt flow on Lanzarote, Canary Islands, contain, in addition to volcanic minerals, quartz and mica, exotic to the island!s bedrock. Kaolinite in the soils also likely has an exotic origin. Trace-element geochemistry shows that the soils are derived from varying proportions of locally derived basalt and African dust. …


The Influence Of Nutrients And Physical Habitat In Regulating Algal Biomass In Agricultural Streams, Mark D. Munn, Jeffrey Frey, Anthony Tesoriero Jan 2010

The Influence Of Nutrients And Physical Habitat In Regulating Algal Biomass In Agricultural Streams, Mark D. Munn, Jeffrey Frey, Anthony Tesoriero

United States Geological Survey: Water Reports and Publications

This study examined the relative influence of nutrients (nitrogen and phosphorus) and habitat on algal biomass in five agricultural regions of the United States. Sites were selected to capture a range of nutrient conditions, with 136 sites distributed over five study areas. Samples were collected in either 2003 or 2004, and analyzed for nutrients (nitrogen and phosphorous) and algal biomass (chlorophyll a). Chlorophyll a was measured in three types of samples, fine-grained benthic material (CHLFG), coarse-grained stable substrate as in rock or wood (CHLCG), and water column (CHLS). Stream and riparian habitat were characterized at each site. TP ranged from …


Development And Application Of A Pollen-Based Paleohydrologic Reconstruction From The Lower Roanoke River Basin, North Carolina, Usa, Debra Willard, Christopher Bernhardt, Roger Brown, Bryan Landacre, Philip A. Townsend Jan 2010

Development And Application Of A Pollen-Based Paleohydrologic Reconstruction From The Lower Roanoke River Basin, North Carolina, Usa, Debra Willard, Christopher Bernhardt, Roger Brown, Bryan Landacre, Philip A. Townsend

United States Geological Survey: Staff Publications

We used pollen assemblages to reconstruct late-Holocene paleohydrologic patterns in floodplain deposits from the lower Roanoke River basin (North Carolina, southeastern USA). Using 120 surface samples from 38 transects, we documented statistical relationships between pollen assemblages, vegetation, and landforms. Backswamp pollen assemblages (long hydroperiods) are dominated by Nyssa (tupelo) and Taxodium (cypress) and have high pollen concentrations. Sediments from elevated levees and seasonally flooded forests (shorter hydroperiods) are characterized by dominant Pinus (pine) pollen, variable abundance of hardwood taxa, and low pollen concentrations. We apply the calibration data set to interpret past vegetation and paleohydrology. Pollen from a radiocarbon-dated sediment …


Droughtscape, Winter 2010, Kelly Smith Jan 2010

Droughtscape, Winter 2010, Kelly Smith

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

USDM Forum Highlights

Drought Likely to Ease

Research Shows Birds Vulnerable to Drought

Drought Recedes in 2009

CA, TX Suffer Impacts from Ongoing Drought

NDMC Wishes Ryu Well

Conferees Pick SPI for Global Drought Index


Paleo-Environmental Changes In The Uvs Nuur Basin (Northwest-Mongolia), Michael Walther Jan 2010

Paleo-Environmental Changes In The Uvs Nuur Basin (Northwest-Mongolia), Michael Walther

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

Geomorphological, geochemical, sedimentological and palynological results are presented against the background of palaeoclimatic changes during the past 15,000 years, yielding a chrono-, bio- and morphostratigraphical model of landscape evolution in the region of northern Central Asia. Holocene and Late-Glacial climatic fluctuations there are shown to correlate well with conditions in central Europe. Particular attention is given to the importance of the palaeoclimatic interpretation of lake Basin sediments when reconstructing the palaeoenvironment.


Absorption And Biotransformation Of Polybrominated Diphenyl Ethers De-71 And De-79 In Chicken (Gallus Gallus), Mallard (Anas Platyrhynchos), American Kestrel (Falco Sparverius) And Black-Crowned Night-Heron (Nycticorax Nycticorax) Eggs, Moira A. Mckernan, Barnett A. Rattner, Jeff S. Hatfield, Robert C. Hale, Mary Ann Ottinger Jan 2010

Absorption And Biotransformation Of Polybrominated Diphenyl Ethers De-71 And De-79 In Chicken (Gallus Gallus), Mallard (Anas Platyrhynchos), American Kestrel (Falco Sparverius) And Black-Crowned Night-Heron (Nycticorax Nycticorax) Eggs, Moira A. Mckernan, Barnett A. Rattner, Jeff S. Hatfield, Robert C. Hale, Mary Ann Ottinger

United States Geological Survey: Staff Publications

We recently reported that air cell administration of penta-brominated diphenyl ether (penta-BDE; DE-71) evokes biochemical and immunologic effects in chicken (Gallus gallus) embryos at very low doses, and impairs pipping (i.e., stage immediately prior to hatching) and hatching success at 1.8 µg g-1 egg (actual dose absorbed) in American kestrels (Falco sparverius). In the present study, absorption of polybrominated diphenyl ether (PBDE) congeners was measured following air cell administration of a penta-BDE mixture (11.1 lg DE-71 g-1 egg) or an octa-brominated diphenyl ether mixture (octa BDE; DE-79; 15.4 lg DE-79 g- …


Combined Effects Of Heat Waves And Droughts On Avian Communities Across The Conterminous United States, Thomas P. Albright, Anna M. Pidgeon, Chadwick D. Rittenhouse, Murray K. Clayton, Brian D. Wardlow, Curtis H. Flather, Patrick D. Culbert, Volker C. Radeloff Jan 2010

Combined Effects Of Heat Waves And Droughts On Avian Communities Across The Conterminous United States, Thomas P. Albright, Anna M. Pidgeon, Chadwick D. Rittenhouse, Murray K. Clayton, Brian D. Wardlow, Curtis H. Flather, Patrick D. Culbert, Volker C. Radeloff

National Drought Mitigation Center: Faculty Publications

Increasing surface temperatures and climatic variability associated with global climate change are expected to produce more frequent and intense heat waves and droughts in many parts of the world. Our goal was to elucidate the fundamental, but poorly understood, effects of these extreme weather events on avian communities across the conterminous United States. Specifically, we explored: (1) the effects of timing and duration of heat and drought events, (2) the effects of jointly occurring drought and heat waves relative to these events occurring in isolation, and (3) how effects vary among functional groups related to nest location and migratory habit, …


Effects Of Lightning And Other Meteorological Factors On Fire Activity In The North American Boreal Forest: Implications For Fire Weather Forecasting, David Peterson, Jun Wang, Charles Ichoku, Lorraine Remer Jan 2010

Effects Of Lightning And Other Meteorological Factors On Fire Activity In The North American Boreal Forest: Implications For Fire Weather Forecasting, David Peterson, Jun Wang, Charles Ichoku, Lorraine Remer

Department of Earth and Atmospheric Sciences: Faculty Publications

The effects of lightning and other meteorological factors on wildfire activity in the North American boreal forest are statistically analyzed during the fire seasons of 2000–2006 through an integration of the following data sets: the MODerate Resolution Imaging Spectroradiometer (MODIS) level 2 fire products, the 3-hourly 32-km gridded meteorological data from North American Regional Reanalysis (NARR), and the lightning data collected by the Canadian Lightning Detection Network (CLDN) and the Alaska Lightning Detection Network (ALDN). Positive anomalies of the 500 hPa geopotential height field, convective available potential energy (CAPE), number of cloud-to-ground lightning strikes, and the number of consecutive dry …


Zebulon Pike: Great American Explorer Or Climate Spy?, Merlin P. Lawson, Randall Cerveny, Cary Mock Jan 2010

Zebulon Pike: Great American Explorer Or Climate Spy?, Merlin P. Lawson, Randall Cerveny, Cary Mock

Department of Earth and Atmospheric Sciences: Faculty Publications

Zebulon Pike is known in history books as one of America’s heroes—a great explorer whose adventures in the American West rivaled the Lewis and Clark Expedition and who became the namesake for Colorado’s Pike’s Peak. But what if the history books got it wrong, and Pike was actually not the hero everyone thinks he is? What if he was actually a spy carrying out a secret mission, or a scoundrel interested in overthrowing the American government and helping to carve a new empire out of the North American Southwest? Evidence from Pike’s famed expedition in 1806-1807 points to the possibility …


Evidence For Recent Population Bottlenecks In Northern Spotted Owls (Strix Occidentalis Caurina), W. Chris Funk, Eric D. Forsman, Matthew Johnson, Thomas D. Mullins, Susan M. Haig Jan 2010

Evidence For Recent Population Bottlenecks In Northern Spotted Owls (Strix Occidentalis Caurina), W. Chris Funk, Eric D. Forsman, Matthew Johnson, Thomas D. Mullins, Susan M. Haig

United States Geological Survey: Staff Publications

The northern spotted owl (Strix occidentalis caurina) is one of the most controversial threatened subspecies ever listed under the US Endangered Species Act. Despite protection of its remaining forest habitat, recent field studies show continued declines of northern spotted owls. One potential threat to northern spotted owls which has not yet been shown is loss of genetic variation from population bottlenecks. Bottlenecks can increase the probability of mating among related individuals, potentially causing inbreeding depression, and can decrease adaptive potential. Here we report evidence for recent bottlenecks in northern spotted owls using a large genetic dataset (352 individuals …


Subspecies Status And Population Genetic Structure In Piping Plover (Charadrius Melodus), Mark P. Miller, Susan M. Haig, Cheri L. Gratto-Trevor, Thomas D. Mullins Jan 2010

Subspecies Status And Population Genetic Structure In Piping Plover (Charadrius Melodus), Mark P. Miller, Susan M. Haig, Cheri L. Gratto-Trevor, Thomas D. Mullins

United States Geological Survey: Staff Publications

Piping Plover (Charadrius melodus) is a migratory shorebird that is listed as endangered in Canada and the U.S. Great Lakes and as threatened throughout the rest of its breeding and winter range. We undertook a comprehensive molecular-genetic investigation to (1) address subspecific taxonomy, (2) characterize population genetic structure, and (3) infer past bottlenecks and demographic processes in this species. Analyses included individuals from 23 U.S. states and Canadian provinces and were based on mitochondrial DNA sequences (580 base pairs, n = 245) and 8 nuclear microsatellite loci (n = 229). Our findings provide support for separate Atlantic and …


The Cleaning Of Burned And Contaminated Archaeological Maize Prior To 87sr/86sr Analysis, L.V. Benson, H. E. Taylor, T. I. Plowman, D. A. Roth, R. C. Antweiler Jan 2010

The Cleaning Of Burned And Contaminated Archaeological Maize Prior To 87sr/86sr Analysis, L.V. Benson, H. E. Taylor, T. I. Plowman, D. A. Roth, R. C. Antweiler

United States Geological Survey: Staff Publications

Accurate trace-metal and strontium-isotope analyses of archaeological corn cobs require that metal contaminants be removed prior to chemical analysis. Archaeological cobs are often coated with construction debris, dust, or soilwhich contains mineral particles. In addition, most archaeological cobs are partially or completely burned and the burned parts incorporate mineral debris in their hardened residual structures. Unburned cobs are weak ion exchangers and most metals within a cob are not firmly bound to cob organic matter; therefore, immersing cobs in acids and rinsing them in deionized water to remove mineral contaminants may result in the undesirable loss of metals, including strontium, …