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Occurrence Of Antimicrobials And Antimicrobial Resistance Genes In Beef Cattle Storage Ponds And Swine Treatment Lagoons, Yuping Zhang, Chiqian Zhang, David B. Parker, Daniel D. Snow, Zhi Zhou, Xu Li Jan 2013

Occurrence Of Antimicrobials And Antimicrobial Resistance Genes In Beef Cattle Storage Ponds And Swine Treatment Lagoons, Yuping Zhang, Chiqian Zhang, David B. Parker, Daniel D. Snow, Zhi Zhou, Xu Li

Nebraska Water Center: Faculty Publications

Livestock manure treatment and storage structures are potential environmental sources of antimicrobials and antimicrobial resistance genes (ARGs). In this study, the occurrence of antimicrobials and ARGs was investigated in the water and the sludge compartments of beef cattle storage ponds and swine lagoons. Analysis was focused on two families of antimicrobials (sulfonamide and tetracycline) and the corresponding ARGs (sul1, sul2, tetO, tetQ and tetX). Results showed that the pseudo-partitioning coefficients of tetracyclines were higher than those of sulfonamides, suggesting different distributions of these two classes of antimicrobials between water and sludge. The ARGs tested were …


A Study Of Ecological And Physiological Roles Of The Termite Associated Verrucomicrobium (Tav) Strains Through A System Biology Approach, Jantiya Isanapong Jan 2013

A Study Of Ecological And Physiological Roles Of The Termite Associated Verrucomicrobium (Tav) Strains Through A System Biology Approach, Jantiya Isanapong

Earth & Environmental Sciences Dissertations - Archive

Termite hindguts are populated by a dense and diverse community of microbial symbionts working in concert to transform lignocellulosic plant material and derived residues into acetate, to recycle and fix nitrogen, and to remove oxygen. Although much has been learned about the breadth of microbial diversity in the hindgut, the ecophysiological roles of its members is less understood. In this study, we present new information about the ecophysiology of microorganism Diplosphaera colotermitum strain TAV2, an autochthonous member of the Reticulitermes flavipes gut community. An integrated high-throughput approach was used to determine the transcriptomic and proteomic profiles of cells grown under …


Oil Pollution In Water Bodies Of Restricted Circulation, Michael A. Kruge Jan 2013

Oil Pollution In Water Bodies Of Restricted Circulation, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Coastal lagoons and embayments near urban centers around the world share many common characteristics and problems. Physical impediments to free water circulation (spits, barrier islands, internal islands, tombolos, submerged sills) often lead to water stagnation and, in the presence of excess nutrients, eutrophication. Urban and industrial activities provoke (usually accidental) spills of hazardous materials into these confined water bodies, such as crude petroleum and refined petroleum products, leading to difficulties for resident biota and potential hazards for human health. The sluggish turnover of these water bodies (or low-energy zones within them) may retard the natural attenuation of the spilled contaminants. …


Chemostratigraphy Of The Early Pliocene Diatomite Interval From Mis And-1b Core (Antarctica): Paleoenvironment Implications, Giovanna Scopelliti, Adriana Bellanca, Donata Monien, Gerhard Kuhn Jan 2013

Chemostratigraphy Of The Early Pliocene Diatomite Interval From Mis And-1b Core (Antarctica): Paleoenvironment Implications, Giovanna Scopelliti, Adriana Bellanca, Donata Monien, Gerhard Kuhn

ANDRILL Research and Publications

The AND-1B drill core (1285 m-long) was recovered, inside the ANDRILL (ANtarctic geological DRILLing) Program, during the austral summer of 2006/07 from beneath the floating McMurdo Ice Shelf. Drilling recovered a stratigraphic succession of alternating diamictites, diatomites and volcaniclastic sediments spanning about the last 14 Ma. A core portion between 350 and 480 mbsf, including a 80 m-thick diatomite interval recording the early Pliocene warming event, was investigated in term of opal biogenic content and element geochemistry. Across the diatomite interval, in spite of the lithological uniformity, a fluctuating biogenic opal profile mirrors the δ18O record, testifying a decrease in …


Geo402/585: Field Methods; Labs 4-5 Gordon Natural Area Carbon Stock Pilot Study, Joy Fritschle Jan 2013

Geo402/585: Field Methods; Labs 4-5 Gordon Natural Area Carbon Stock Pilot Study, Joy Fritschle

Gordon Natural Area-related Curricula Documents

No abstract provided.


Topographic Signatures And A General Transport Law For Deep-Seated Landslides In A Landscape Evolution Model, Adam M. Booth, Joshua J. Roering, Alan W. Rempel Jan 2013

Topographic Signatures And A General Transport Law For Deep-Seated Landslides In A Landscape Evolution Model, Adam M. Booth, Joshua J. Roering, Alan W. Rempel

Geology Faculty Publications and Presentations

A fundamental goal of studying earth surface processes is to disentangle the complex web of interactions among baselevel, tectonics, climate, and rock properties that generate characteristic landforms. Mechanistic geomorphic transport laws can quantitatively address this goal, but no widely accepted law for landslides exists. Here we propose a transport law for deep-seated landslides in weathered bedrock and demonstrate its utility using a two-dimensional numerical landscape evolution model informed by study areas in the Waipaoa catchment, New Zealand, and the Eel River catchment, California. We define a non-dimensional landslide number, which is the ratio of the horizontal landslide flux to the …


Distribution Of Soil Density At A Bottomland Hardwood Forest Wetland Restoration, Chicot County, Arkansas, B. E. Sleeper, Robert L. Ficklin Jan 2013

Distribution Of Soil Density At A Bottomland Hardwood Forest Wetland Restoration, Chicot County, Arkansas, B. E. Sleeper, Robert L. Ficklin

Journal of the Arkansas Academy of Science

Bottomland hardwood forest (BLHF) soils provide a myriad of ecosystem services, yet much information is lacking with respect to how soil physical properties influence biogeochemical cycling along topographic gradients. Current patterns of vegetation at a 149ha wetland restoration site in Chicot County, Arkansas, suggest the presence of ecologically significant variation in soil properties within the Perry Clay soil series. A study was initiated in the Lower Mississippi Alluvial Valley (LMAV) to map soil bulk density and texture as well as to identify the interrelationships between soil physical properties, soil organic carbon, and total nitrogen. A random grid was used to …


Colour Origin Of Red Sandstone Beds Within The Hüdai Formation (Early Cambrian), Aydıncık (Mersin), Southern Turkey, Muhsi̇n Eren, Selahatti̇n Kadi̇r Jan 2013

Colour Origin Of Red Sandstone Beds Within The Hüdai Formation (Early Cambrian), Aydıncık (Mersin), Southern Turkey, Muhsi̇n Eren, Selahatti̇n Kadi̇r

Turkish Journal of Earth Sciences

The basal part of the Hüdai Formation (Early Cambrian) in the Aydıncık (Mersin) area comprises red sandstone beds at different stratigraphic levels, showing ripple cross-lamination. These beds were deposited in the middle to lower part of an intertidal flat environment. Bedding-parallel reddening and its cyclic character suggest syn-sedimentary or early diagenetic red colouration in a marine environment. Both X-ray diffraction and petrographic analyses indicate that the red sandstones are composed of predominantly K-feldspar and quartz grains and an illite matrix. These are dominantly arkosic wacke. A small amount of hematite (


The Key Role Of Micromorphology In Studies Of The Genesis Of Clay Minerals And Their Associations In Soils And Its Relevance To Advances In The Philosophy Of Soil Science, Gordon Jock Churchman Jan 2013

The Key Role Of Micromorphology In Studies Of The Genesis Of Clay Minerals And Their Associations In Soils And Its Relevance To Advances In The Philosophy Of Soil Science, Gordon Jock Churchman

Turkish Journal of Earth Sciences

Micromorphological observations from 3 different published works have been studied to aid understanding of aggregation and of colloids, both unique to soils. Saprolites in Hong Kong included ‘veins’ of different thicknesses and colours. Optical mineralogy identified them as infill from the neogenesis of clays in rock fractures. The common thicker infills resulted from weathering. Dark infill contained comminuted primary minerals whereas thin pale infill originated hydrothermally. Scanning electron microscopy (SEM) showed that the size, shape, and mineralogy of the kaolin minerals formed in infill depended on the types of cracks in the saprolites and on drying. Energy-dispersive X-ray spectroscopy analyses …


Challenges Of Cave Management In A Developing Country: A Case Study Of Grotte Marie-Jeanne, Departemente Sud, Haiti, Patricia N. Kambesis, Brian Oakes, Michael Lace Jan 2013

Challenges Of Cave Management In A Developing Country: A Case Study Of Grotte Marie-Jeanne, Departemente Sud, Haiti, Patricia N. Kambesis, Brian Oakes, Michael Lace

National Cave and Karst Management Symposium 2013

As with many developing countries,Haiti has environmental, economic and cultural challenges that complicate natural resource management. Karst landscapes dominate Haiti and caves are abundant as recent cave and karst inventory data indicate. Though the caves and karst are subject to environmental challenges they also provide the potential for the development of tourism that would improve local economic conditions. There are 500 documented caves in Haiti of which, five are show caves. Of those, only one, Grotte Marie-Jeanne, located in Port-ấ -Piment in Departement Sud, has a structured cave management plan that addresses identification of cave resources, visitor access, interpretive guidelines, …


Water Column Variability In A Coastal Tourist Cave In Mallorca, Spain, Liana M. Boop, Bogdan P. Onac, Jonathan G. Wynn, Joan J. Fornós, Marta Rodríguez-Homar Jan 2013

Water Column Variability In A Coastal Tourist Cave In Mallorca, Spain, Liana M. Boop, Bogdan P. Onac, Jonathan G. Wynn, Joan J. Fornós, Marta Rodríguez-Homar

National Cave and Karst Management Symposium 2013

Coves del Drac is visited by more than 1 million tourists annually and has been a tourist destination in the western Mediterranean for over 100 years. All areas of the cave are developed with historic or current tour route infrastructure, including walkways, handrails, and electric lighting. This study compares one vertical water profile collected along the current tour path with two other profiles from historic tour route locations. Differences in freshwater and organic inputs, as well as direct anthropogenic impacts, are clearly observed in the aquatic parameters and stable isotopes collected in the profiles. Anthropogenically-driven undersaturation in the cave pools, …


Arsenic And Phosphorus Biogeochemistry In The Ocean: Arsenic Species As Proxies For P-Limitation, Oliver Wurl, Louise Zimmer, Gregory A. Cutter Jan 2013

Arsenic And Phosphorus Biogeochemistry In The Ocean: Arsenic Species As Proxies For P-Limitation, Oliver Wurl, Louise Zimmer, Gregory A. Cutter

OES Faculty Publications

Arsenic and phosphorus are biochemically very similar, and hence arsenate (As5+) is toxic by interfering with the energy metabolism, in particular during P limitation. However, many phytoplankton detoxify As by reducing arsenate to arsenite (As3+), and/or methylating it to mono and dimethyl As. Such As detoxification becomes operative in oligotrophic waters when phosphate concentrations are below those for As; therefore, we evaluated the potential use of these detoxification products as indicators of P-limitation by measuring As speciation during the US GEOTRACES North Atlantic transect. The distribution of As3+ concentrations in surface waters is similar to …


Phosphorus Cycling In The Sargasso Sea: Investigation Using The Oxygen Isotopic Composition Of Phosphate, Enzyme-Labeled Fluorescence, And Turnover Times, Karen Mclaughlin, Jill A. Sohm, Gregory A. Cutter, Michael W. Lomas, Adina Paytan Jan 2013

Phosphorus Cycling In The Sargasso Sea: Investigation Using The Oxygen Isotopic Composition Of Phosphate, Enzyme-Labeled Fluorescence, And Turnover Times, Karen Mclaughlin, Jill A. Sohm, Gregory A. Cutter, Michael W. Lomas, Adina Paytan

OES Faculty Publications

Dissolved inorganic phosphorus (DIP) concentrations in surface water of vast areas of the ocean are extremely low (<10 nM) and phosphorus (P) availability could limit primary productivity in these regions. We explore the use of oxygen isotopic signature of dissolved phosphate (δ18OPO4) to investigate biogeochemical cycling of P in the Sargasso Sea, Atlantic Ocean. Additional techniques for studying P dynamics including 33P-based DIP turnover time estimates and percent of cells expressing alkaline phosphatase (AP) activity as measured by enzyme-labeling fluorescence are also used. In surface waters, δ18OPO4 values were lower than equilibrium by 3–6%, indicative of dissolved organic phosphorous (DOP) remineralization by extracellular enzymes. An isotope mass balance model using a variety of possible combinations of …


Using Ammonium Pore Water Profiles To Assess Stoichiometry Of Deep Remineralization Processes In Methanogenic Continental Margin Sediments, David J. Burdige, Tomoko Komada Jan 2013

Using Ammonium Pore Water Profiles To Assess Stoichiometry Of Deep Remineralization Processes In Methanogenic Continental Margin Sediments, David J. Burdige, Tomoko Komada

OES Faculty Publications

In many continental margin Sediments, a deep reaction zone exists which is separated from remineralization processes near the sediment surface. Here, methane diffuses upward to a depth where it is oxidized by downwardly diffusing sulfate. However, the methane sources that drive this anaerobic oxidation of methane (AOM) in the sulfate-methane transition zone (SMT) may vary among sites. In particular, these sources can be thought of as either (i) "internal" sources from in situ methanogenesis (regardless of where it occurs in the sediment column) that are ultimately coupled to organic matter deposition and burial, or (ii) "external" sources such as hydrocarbon …


Distributions Of Particulate Heme B In The Atlantic And Southern Oceans- Implications For Electron Transport In Phytoplankton, Martha Gledhill, Eric P. Achterberg, David J. Honey, Maria C. Nielsdottir, Micha J.A. Rijkenberg Jan 2013

Distributions Of Particulate Heme B In The Atlantic And Southern Oceans- Implications For Electron Transport In Phytoplankton, Martha Gledhill, Eric P. Achterberg, David J. Honey, Maria C. Nielsdottir, Micha J.A. Rijkenberg

OES Faculty Publications

Concentrations of heme b, the iron-containing component of b-type hemoproteins, ranged from b concentrations were enhanced in the photic zone and decreased with depth. Heme b concentrations correlated positively with chlorophyll a (chl a) in the TNA (r=0.41, pb did not correlate with chl a in the IB or SS. In the IB and SS, stations with high-chlorophyll and low-nutrient (Fe and/or Si) concentrations exhibited low heme bconcentrations relative to particulate organic carbon (< 0.1 μmolmol-1, and high chl a:heme b ratios (> 500). High chl a:heme b ratios resulted from relative decreases in …


Microbially Induced Sedimentary Structures Recording An Ancient Ecosystem In The Ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia, Nora Noffke, Daniel Christian, David Wacey, Robert M. Hazen Jan 2013

Microbially Induced Sedimentary Structures Recording An Ancient Ecosystem In The Ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia, Nora Noffke, Daniel Christian, David Wacey, Robert M. Hazen

OES Faculty Publications

Microbially induced sedimentary structures (MISS) result from the response of microbial mats to physical sediment dynamics. MISS are cosmopolitan and found in many modern environments, including shelves, tidal flats, lagoons, riverine shores, lakes, interdune areas, and sabkhas. The structures record highly diverse communities of microbial mats and have been reported from numerous intervals in the geological record up to 3.2 billion years (Ga) old. This contribution describes a suite of MISS from some of the oldest well-preserved sedimentary rocks in the geological record, the early Archean (ca. 3.48 Ga) Dresser Formation, Western Australia. Outcrop mapping at the meter to …


Stromatolites And Miss—Differences Between Relatives, N. Noffke, S. M. Awramik Jan 2013

Stromatolites And Miss—Differences Between Relatives, N. Noffke, S. M. Awramik

OES Faculty Publications

Benthic microorganisms form highly organized communities called “biofilms.” A biofilm consists of the individual cells plus their extracellular polymeric substances (EPS). In marine and non-marine environments, benthic microbial communities interact with the physical sediment dynamics and other factors in the environment in order to survive. This interaction can produce distinctive sedimentary structures called microbialites. Binding, biostabilization, baffling, and trapping of sediment particles by microorganisms result in the formation of microbially induced sedimentary structures (MISS); however, if carbonate precipitation occurs in EPS, and these processes happen in a repetitive manner, a multilayered build-up can form—stromatolites. Stromatolites and MISS are first found …


Swat Model Simulation Of Bioenergy Crop Impacts In A Tile-Drained Watershed, Chelsie Marie Werling Boles Jan 2013

Swat Model Simulation Of Bioenergy Crop Impacts In A Tile-Drained Watershed, Chelsie Marie Werling Boles

Open Access Theses

Tile drains are an important component of agricultural production in the Midwest, and their inclusion in modeling studies is important in watersheds where they are a principal hydrologic pathway. The new tile drainage simulation method in the Soil Water Assessment Tool (SWAT) was parameterized and tile flow results were compared with reviewed literature. Streamflow, sediment, and nutrient outputs were compared to measured values and simulated crop yields were examined with respect to average county yields. Plant growth stressors were examined to account for differences between simulated and published yields. The bioenergy crop switchgrass (Panicum virgatum) was applied over …


Identifying Ditch Geometry And Top Of The Bank Location Using Airborne Lidar Point Cloud, Naime Celik Jan 2013

Identifying Ditch Geometry And Top Of The Bank Location Using Airborne Lidar Point Cloud, Naime Celik

Open Access Theses

The geometry of agricultural drainage ditches is very important in crop production as it impacts drainage of cropland and affects vegetation and soil erosion along the banks of the ditches. Thus, implementation of water conservation and management practices in engineered and natural ditches necessitates determination of ditch geometry along the reach of the ditch. This study explores the use of airborne commercial Light Detection and Ranging (LiDAR) technology to identify the top of the ditch banks. The method was developed to obtain the normalized cross sectional shape of the ditch using one-dimensional spline fits to ground classified points from the …


Slurry Seeding Cover Crops, Edwin Alexander Suarez Jan 2013

Slurry Seeding Cover Crops, Edwin Alexander Suarez

Open Access Theses

Cover crops improve soil quality through increased organic matter, biological activity, aggregate stability, water infiltration, and nutrient cycling. Slurry seeding, the co-application of cover crop seed and swine (Sus domesticus) manure, is a new practice that saves fuel, time and labor. High salinity and/or ammonia, among other components in swine manure, may reduce cover crop seed germination and limit the use of slurry seeding. Ten cover crop species were evaluated to compare the effects of swine manure components on cover crop seed germination. Seed germination percentages and rates were affected by swine manure but not by equivalent salinity levels established …


An Evaluation Of Spatial Variability Of Water Stress Index Across The United States: Implications Of Supply And Demand In The East Vs The West, Jennifer Ann Roath Jan 2013

An Evaluation Of Spatial Variability Of Water Stress Index Across The United States: Implications Of Supply And Demand In The East Vs The West, Jennifer Ann Roath

Open Access Theses

In order to support both human and environmental needs, high quality fresh water must be available when and where it is required. As a metric for indicating unsustainable water usage, WSI is only useful when the values reflect accurate interactions between supply and demand; however, the complexity of temporal and spatial variability of available fresh water complicates the analysis of water stress.

The overall goal of this project was to investigate the spatial variability of water stress across the United States and the appropriate spatial scale for management decisions. To accomplish this, a national dataset describing spatial distribution and breakdown …


Improving Model Performance For Invasive Plant Species Distribution Using Global-Scale Presence-Only Data: Parameterization And Data Quality, Feng Yu Jan 2013

Improving Model Performance For Invasive Plant Species Distribution Using Global-Scale Presence-Only Data: Parameterization And Data Quality, Feng Yu

Open Access Theses

Invasive species have significant ecological and economic impacts. To control species' invasion, risk assessment provides the most essential information for identification and evaluation of the potential risk of the invasive species, especially in their early invasion stages. Species distribution models (SDMs) is the foundation for risk assessment, in terms of both the practical and theoretical interest in our understanding of species invasion process. SDMs contribute to the proactive invasion management and the test of ecological or biogeographical hypotheses about species distributions in relation to their environment.

However, modeling of invasive species at large spatial scale (i.e., cross-continental) is rarely discussed. …


Modeling Bedrock Mining Hotspots Within The Ouachita National Forest, Arkansas, Stephanie H. Mehlhope Jan 2013

Modeling Bedrock Mining Hotspots Within The Ouachita National Forest, Arkansas, Stephanie H. Mehlhope

Theses and Dissertations--Geography

This study, concentrating on the Ouachita Mountain Range in western-central Arkansas, extends prior work on treethrows and their influence on soil development in the region by supplying a method of determining hotspots of bedrock mining by treethrow. Binary logistic regression analysis was employed to determine the abiotic and biotic factors that are highly correlated with the rate of bedrock detachment found in uprooted rootwads from three study sites within the Ouachita National Forest. The produced logistic regression models suggest topographic factors, tree specific characteristics, as well as the local geology and soil characteristics all have a significant effect upon the …


Revisiting The Genesis Of Red Mediterranean Soils, Nicolas Fedoroff, Marie-Agnes Courty Jan 2013

Revisiting The Genesis Of Red Mediterranean Soils, Nicolas Fedoroff, Marie-Agnes Courty

Turkish Journal of Earth Sciences

This work, aside from being a classical discussion on the processes of rubefaction and illuviation, is an attempt to cross the abundant literature on red Mediterranean soils (RMSs) written by pedologists, and also by paleopedologists and geologists, with the climatic frame established by paleoclimatologists for the Quaternary. Such an approach leads us to consider that the development of the RMSs was discontinuous, occurring during periods of environmental stability, i.e. interglacials, characterized by a humid climate (precipitations exceeding evapotranspiration) with dry and hot summers. The impact of glacial intervals on the RMS covers is presently only partially documented. Aeolian processes during …


Palaeoenvironmental And Chronological Constraints On The Tuğlu Formation (Çankırı Basin, Central Anatolia, Turkey), Ilaria Mazzini, Natalia Hudáková, Peter Joniak, Marianna Kovacova, Tamás Mikes, Andreas Mulch, Fuat Bora Rojay, Stella Lucifora, Daniela Esu, Ingeborg Soulie-Marsche Jan 2013

Palaeoenvironmental And Chronological Constraints On The Tuğlu Formation (Çankırı Basin, Central Anatolia, Turkey), Ilaria Mazzini, Natalia Hudáková, Peter Joniak, Marianna Kovacova, Tamás Mikes, Andreas Mulch, Fuat Bora Rojay, Stella Lucifora, Daniela Esu, Ingeborg Soulie-Marsche

Turkish Journal of Earth Sciences

The Çankırı Basin, located in the northern part of the Central Anatolian Plateau, is a large Tertiary basin where thick Miocene to Quaternary continental sediments overlay the Cretaceous-Tertiary units. This investigation focuses on the Tuğlu Formation, an Upper Miocene succession mainly composed of dark grey silty and organic rich clays. The type section of Tuğlu has been sampled for an array of multidisciplinary analyses. The palaeontological proxies included ostracod, foraminifer, nannoplankton, pollen, molluscs, charophytes, small mammal assemblages, fish, and crab remains. The abiotic parameters studied were: palaeomagnetism and environmental magnetism, stable carbon and oxygen isotope ratios (on ostracods and bulk …


Fumigation Of A Laboratory-Scale Hvac System With Hydrogen Peroxide For Decontamination Following A Biological Contamination Incident, K. M. Meyer, M. W. Calfee, J. P. Wood, L. Michelsen, B. Attwood, M. Clayton, A. Touati, R. Delafield Jan 2013

Fumigation Of A Laboratory-Scale Hvac System With Hydrogen Peroxide For Decontamination Following A Biological Contamination Incident, K. M. Meyer, M. W. Calfee, J. P. Wood, L. Michelsen, B. Attwood, M. Clayton, A. Touati, R. Delafield

United States Environmental Protection Agency: Publications

Aims

To evaluate hydrogen peroxide vapor (H2O2) for its ability to inactivate Bacillus spores within a laboratory-scale heating, ventilation and air-conditioning (HVAC) duct system.

Methods and Results

Experiments were conducted in a closed-loop duct system, constructed of either internally lined or unlined galvanized metal. Bacterial spores were aerosol-deposited onto 18-mm-diameter test material coupons and strategically placed at several locations within the duct environment. Various concentrations of H2O2 and exposure times were evaluated to determine the sporicidal efficacy and minimum exposure needed for decontamination. For the unlined duct, high variability was observed in the …


Effects Of Chiloquin Dam On Spawning Distribution And Larval Emigration Of Lost River, Shortnose, And Klamath Largescale Suckers In The Williamson And Sprague Rivers, Oregon, Barbara A. Martin, David A. Hewitt, Craig M. Ellsworth Jan 2013

Effects Of Chiloquin Dam On Spawning Distribution And Larval Emigration Of Lost River, Shortnose, And Klamath Largescale Suckers In The Williamson And Sprague Rivers, Oregon, Barbara A. Martin, David A. Hewitt, Craig M. Ellsworth

United States Geological Survey: Publications

Chiloquin Dam was constructed in 1914 on the Sprague River near the town of Chiloquin, Oregon. The dam was identified as a barrier that potentially inhibited or prevented the upstream spawning migrations and other movements of endangered Lost River (Deltistes luxatus) and shortnose (Chasmistes brevirostris) suckers, as well as other fish species. In 2002, the Bureau of Reclamation led a working group that examined several alternatives to improve fish passage at Chiloquin Dam. Ultimately it was decided that dam removal was the best alternative and the dam was removed in the summer of 2008. The U.S. …


Impacts Of Migratory Sandhill Cranes (Grus Canadensis) On Microbial Water Quality In The Central Platte River, Nebraska, Usa, Jason R. Vogel, Dale W. Griffin, Hon S. Ip, Nicholas J. Ashbolt, Matthew T. Moser, Jingrang Lu, Mary K. Beitz, Hodon Ryu, Jorge W. Santo Domingo Jan 2013

Impacts Of Migratory Sandhill Cranes (Grus Canadensis) On Microbial Water Quality In The Central Platte River, Nebraska, Usa, Jason R. Vogel, Dale W. Griffin, Hon S. Ip, Nicholas J. Ashbolt, Matthew T. Moser, Jingrang Lu, Mary K. Beitz, Hodon Ryu, Jorge W. Santo Domingo

United States Geological Survey: Staff Publications

Wild birds have been shown to be significant sources of numerous types of pathogens that are relevant to humans and agriculture. The presence of large numbers of migratory birds in such a sensitive and important ecosystem as the Platte River in central Nebraska, USA, could potentially serve a significant source of birdderived pathogens in the water/sediment and riverine environment. In 2009 and 2010, a study was completed to investigate the potential water-quality impacts of Sandhill Cranes and Snow Geese on the microbial water quality of the central Platte River during their spring migration period. Fecal material, river-bottom sediment, and water …


Controls On Recent Alaskan Lake Changes Identified From Water Isotopes And Remote Sensing, Lesleigh Anderson, Jennifer Rover, Nikki Gaulager, Jean Birks Jan 2013

Controls On Recent Alaskan Lake Changes Identified From Water Isotopes And Remote Sensing, Lesleigh Anderson, Jennifer Rover, Nikki Gaulager, Jean Birks

United States Geological Survey: Staff Publications

High-latitude lakes are important for terrestrial carbon dynamics and waterfowl habitat driving a need to better understand controls on lake area changes. To identify the existence and cause of recent lake area changes in the Yukon Flats, a region of discontinuous permafrost in north central Alaska, we evaluate remotely sensed imagery with lake water isotope compositions and hydroclimatic parameters. Isotope compositions indicate that mixtures of precipitation, river water, and groundwater source ~95% of the studied lakes. The remaining minority are more dominantly sourced by snowmelt and/or permafrost thaw. Isotope-based water balance estimates indicate 58% of lakes lose more than half …


Ice-Age Megafauna In Arctic Alaska: Extinction, Invasion, Survival, Daniel H. Mann, Pamela Groves, Michael L. Kunz, Richard E. Reanier, Benjamin V. Gaglioti Jan 2013

Ice-Age Megafauna In Arctic Alaska: Extinction, Invasion, Survival, Daniel H. Mann, Pamela Groves, Michael L. Kunz, Richard E. Reanier, Benjamin V. Gaglioti

United States Geological Survey: Staff Publications

Radical restructuring of the terrestrial, large mammal fauna living in arctic Alaska occurred between 14,000 and 10,000 years ago at the end of the last ice age. Steppe bison, horse, and woolly mammoth became extinct, moose and humans invaded, while muskox and caribou persisted. The ice age mega fauna was more diverse in species and possibly contained 6x more individual animals than live in the region today. Mega faunal biomass during the last ice age may have been 30x greater than present. Horse was the dominant species in terms of number of individuals. Lions, short-faced bears, wolves, and possibly grizzly …