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A Small-Scale Water Budget Approach And Water Quality Assessment: A Case Study For Calderas Lake, Guatemala, Edrick Ramos Jan 2016

A Small-Scale Water Budget Approach And Water Quality Assessment: A Case Study For Calderas Lake, Guatemala, Edrick Ramos

Dissertations, Master's Theses and Master's Reports

Increases in water demand and urban development in Calderas community over the past decade have led to questions about the hydrology, water quality, quantity and sustainable management of Calderas Lake micro-basin. However, studies on baseline hydrology are limited for rural communities located inside volcanic origin watersheds of Guatemala. The scope of this study was to characterize the hydrology and establish a method to: 1) quantify a water budget, and 2) qualify the water quality of a lacustrine system that supply water for about 17,000 inhabitants on the state limits or rural Guatemala City. Mean annual rainfall and temperature at the …


Geochemistry Of Aegean Sea Sediments: Implications For Surface- And Bottom-Water Conditions During Sapropel Deposition Since Mis 5, Ekrem Bursi̇n İşler, Ali̇ Engi̇n Aksu, Richard Nicholas Hiscott Jan 2016

Geochemistry Of Aegean Sea Sediments: Implications For Surface- And Bottom-Water Conditions During Sapropel Deposition Since Mis 5, Ekrem Bursi̇n İşler, Ali̇ Engi̇n Aksu, Richard Nicholas Hiscott

Turkish Journal of Earth Sciences

Piston cores collected from the Aegean Sea provide a record of sapropel sequence S1, S3-S5. Primary productivity calculations using the equations of Müller and Suess suggest surface paleoproductivities ranged from 180 to 995 g C m-2 year-1 for sapropels and from 40 to 180 g C m-2 year-1 for nonsapropel sediments with corresponding total organic carbon values of 9%-12% and 1%-3%, respectively. The higher paleoproductivities exceed those in the most fertile modern upwelling zones, so are probably overestimated. Instead, enhanced preservation, particularly for S4 and S5, likely resulted from poor bottom-water ventilation beneath a salinity-stratified water column. If the preservation …


Identification Of Putative Geographically Isolated Wetlands Of The Conterminous United States, Charles R. Lane, Ellen D'Amico Jan 2016

Identification Of Putative Geographically Isolated Wetlands Of The Conterminous United States, Charles R. Lane, Ellen D'Amico

United States Environmental Protection Agency: Publications

Geographically isolated wetlands (GIWs) are wetlands completely surrounded by uplands. While common throughout the United States (U.S.), there have heretofore been no nationally available, spatially explicit estimates of GIW extent, complicating efforts to understand the myriad biogeochemical, hydrological, and habitat functions of GIWs and hampering conservation and management efforts at local, state, and national scales. We used a 10-m geospatial buffer as a proxy for hydrological or ecological connectivity of National Wetlands Inventory palustrine and lacustrine wetland systems to nationally mapped and available stream, river, and lake data. We identified over 8.3 million putative GIWs across the conterminous U.S., encompassing …


Water Consumption Estimates Of The Biodiesel Process In The Us, Qingshi Tu, Mingming Lu, Y. Jeffrey Yang, Don Scott Jan 2016

Water Consumption Estimates Of The Biodiesel Process In The Us, Qingshi Tu, Mingming Lu, Y. Jeffrey Yang, Don Scott

United States Environmental Protection Agency: Publications

As a renewable alternative to petroleum diesel, biodiesel has been widely used in the US and the world. However, its potential impact on water resources has not been much evaluated. This study investigates water consumption from the biodiesel process, which includes three stages: soybean irrigation, soybean-to-soybean oil processing, and biodiesel manufacturing, at both national and state levels. Mass-based allocation is performed and water consumption at the three stages is obtained on the basis of million gallons per year and gallon water per gallon biodiesel (gal/gal). The normalized water consumption (water intensity) of the irrigation, oil processing, and biodiesel production stages …


Quantitative Structure–Mesothelioma Potency Model Optimization For Complex Mixtures Of Elongated Particles In Rat Pleura: A Retrospective Study, Philip M. Cook, Joseph Swintek, Timothy D. Dawson, David Chapman, Mathew A. Etterson, Dale Hoff Jan 2016

Quantitative Structure–Mesothelioma Potency Model Optimization For Complex Mixtures Of Elongated Particles In Rat Pleura: A Retrospective Study, Philip M. Cook, Joseph Swintek, Timothy D. Dawson, David Chapman, Mathew A. Etterson, Dale Hoff

United States Environmental Protection Agency: Publications

Cancer potencies of mineral and synthetic elongated particle mixtures, including asbestos fibers, are influenced by changes in fiber dose composition, bioavailability, and biodurability in combination with relevant cytotoxic dose-response relationships. An extensive rat intrapleural dose characterization data set with a wide variety of elongated particles physicochemical properties facilitated statistical analyses of pleural mesothelioma response data combined from several studies for evaluation of alternative dose-response models. Utilizing logistic regression of individual elongated particle dimensional variations within each test sample, four major findings emerged: (1) Mild acid leaching provides superior prediction of tumor incidence compared to samples that were not leached; (2) …


Gross And Microscopic Lesions In Corals From Micronesia, T. M. Work, G. S. Aeby, K. A. Hughen Jan 2016

Gross And Microscopic Lesions In Corals From Micronesia, T. M. Work, G. S. Aeby, K. A. Hughen

United States Geological Survey: Staff Publications

The authors documented gross and microscopic morphology of lesions in corals on 7 islands spanning western, southern, and eastern Micronesia, sampling 76 colonies comprising 30 species of corals among 18 genera, with Acropora, Porites, and Montipora dominating. Tissue loss comprised the majority of gross lesions sampled (41%), followed by discoloration (30%) and growth anomaly (29%). Of 31 cases of tissue loss, most lesions were subacute (48%), followed by acute and chronic (26% each). Of 23 samples with discoloration, most were dark discoloration (40%), with bleaching and other discoloration each constituting 30%. Of 22 growth anomalies, umbonate growth anomalies composed …


A Personal Perspective On Searching For The Ivory-Billed Woodpecker: A 41-Year Quest, Paul W. Sykes Jr. Jan 2016

A Personal Perspective On Searching For The Ivory-Billed Woodpecker: A 41-Year Quest, Paul W. Sykes Jr.

United States Geological Survey: Staff Publications

I first learned about the Patuxent Wildlife Research Center (Patuxent) in Laurel, MD, while attending high school in the mid-1950s. Patuxent wildlife biologists Brooke Meanley, Chandler (Chan) S. Robbins, and Robert (Bob) E. Stewart, Sr., visited me at my parents’ home in Norfolk, VA. I was the compiler of the Norfolk County Christmas Bird Count (which included the eastern portion of the Virginia sector of the Dismal Swamp). As part of that count, we had for several years been estimating populations of red-winged blackbirds (Agelaius phoeniceus) and common grackles (Quiscalus quiscula) in the millions. Patuxent was …


Patuxent’S Role In The Development Of The North American Breeding Bird Survey, John R. Sauer Jan 2016

Patuxent’S Role In The Development Of The North American Breeding Bird Survey, John R. Sauer

United States Geological Survey: Staff Publications

The North American Breeding Bird Survey (BBS) is a roadside survey of the breeding birds of North America. The BBS provides data from the contiguous United States, Alaska, southern and central Canada, and northern Mexico. Begun in 1966 by Chandler (Chan) S. Robbins at the U.S. Geological Survey (USGS) Patuxent Wildlife Research Center (Patuxent), and now jointly managed by Patuxent, the Canadian Wildlife Service, and the Mexican Commission for the Knowledge and Use of Biodiversity, the survey is conducted primarily in June along more than 5,000 roadside survey routes that are surveyed once each year. Volunteer observers drive the 39.4-kilometer …


Patuxent’S Long-Term Research On Wolves, David L. Mech Jan 2016

Patuxent’S Long-Term Research On Wolves, David L. Mech

United States Geological Survey: Staff Publications

The gray wolf (Canis lupus) was one of the first species placed on the Endangered Species List in 1967. The Endangered Species Act of 1973 legally protected the wolf along with other listed species. Patuxent Wildlife Research Center (Patuxent) in Laurel, MD, began its Endangered Wildlife Program in 1966, and U.S. Fish and Wildlife Service (USFWS) biologist Ray Erickson was assigned to lead it. In 1973, I was transferred to the program from Region 3 of the USFWS, having been employed there since 1969 to study wolves in Minnesota. Endangered Species Act protection of the wolf fostered its …


Phosphorus Retention In A Lowland Neotropical Stream Following An Eight-Year Enrichment Experiment, Gaston E. Small, Marcelo Ardón, John H. Duff, Alan P. Jackman, Alonso Ramírez, Frank J. Triska, Catherine M. Pringle Jan 2016

Phosphorus Retention In A Lowland Neotropical Stream Following An Eight-Year Enrichment Experiment, Gaston E. Small, Marcelo Ardón, John H. Duff, Alan P. Jackman, Alonso Ramírez, Frank J. Triska, Catherine M. Pringle

United States Geological Survey: Staff Publications

Human alteration of the global P cycle has led to widespread P loading in freshwater ecosystems. Much research has been devoted to the capacity of wetlands and lakes to serve as long-term sinks for P inputs from the watershed, but we know much less about the potential of headwater streams to serve in this role. We assessed storage and retention of P in biotic and abiotic compartments after an 8-y experimental P addition to a 1st-order stream in a Neotropical wet forest. Sediment P extractions indicated that nearly all P storage was in the form of Fe- and Al-bound P …


Hegranesþing On Hegranes: Geophysical Prospection Interim Report 2013 – 2015, Brian N. Damiata, John M. Steinberg, John W. Schoenfelder, Douglas J. Bolender Jan 2016

Hegranesþing On Hegranes: Geophysical Prospection Interim Report 2013 – 2015, Brian N. Damiata, John M. Steinberg, John W. Schoenfelder, Douglas J. Bolender

Andrew Fiske Memorial Center for Archaeological Research Publications

Geophysical surveys were conducted at Hegranesþing on Hegranes in North Icelad during the summers of 2013 and 2015.


Late Ordovician Tectonism In The North American Midcontinent: Constraints From U-Pb Detrital Zircon Geochronology, Daniel Nathan Meehan I Jan 2016

Late Ordovician Tectonism In The North American Midcontinent: Constraints From U-Pb Detrital Zircon Geochronology, Daniel Nathan Meehan I

Masters Theses

"Numerous sandstone filled depressions hosted in upper Cambrian to Middle Ordovociain dolostones in south-central Missouri have historically been identified as Pennsylvanian paleokarst structures. U-Pb detrital zircon geochronology is at odds the time of formation and sedimentological evidence challenges their classification. "Filled sink" deposits yield primary zircon age populations of 2.8-2.6 Ga (~50% of all analyzed grains), 1.2-1.1 Ga (~25%), 1.8-1.6 Ga (~15%) and 1.5-1.3 Ga (~10%). These zircon populations most likely originated from the Superior Craton and Midcontinent Rift and/or Grenville orogen, respectively. The Warrensburg and Moberly channel-fill sandstones of central Missouri were identified as good candidates for Pennsylvanian aged …


Integration Of Deterministic And Stochastic Models In A 1,4-Dioxane Contaminated Glacial Aquifer System, Washtenaw County, Michigan, Lena Kristin Pappas Jan 2016

Integration Of Deterministic And Stochastic Models In A 1,4-Dioxane Contaminated Glacial Aquifer System, Washtenaw County, Michigan, Lena Kristin Pappas

Wayne State University Theses

Hybrid models incorporating stochastic variability within a deterministic hydrostratigraphic framework provide an effective way to assess uncertainty in flow and transport model predictions. This study evaluated the distribution of groundwater flow and contaminant transport pathways in two ensembles of spatially variable hydraulic conductivity (K) distributions. The models comprised a 360 ft-thick sequence of Pleistocene glacial sediments in in an approximately 8 mi2 area across Washtenaw County, Michigan. Conditioned K fields were generated using Sequential Gaussian Simulation (SGS) and Sequential Indicator Simulation (SIS) constructed using indicator classes based on natural gamma ray logs from 77 monitoring wells. K fields were modeled …


A Fossilized Energy Distribution Of Lightning, Matthew A. Pasek, Marc Hurst Jan 2016

A Fossilized Energy Distribution Of Lightning, Matthew A. Pasek, Marc Hurst

School of Geosciences Faculty and Staff Publications

When lightning strikes soil, it may generate a cylindrical tube of glass known as a fulgurite. The morphology of a fulgurite is ultimately a consequence of the energy of the lightning strike that formed it, and hence fulgurites may be useful in elucidating the energy distribution frequency of cloud-to-ground lightning. Fulgurites from sand mines in Polk County, Florida, USA were collected and analyzed to determine morphologic properties. Here we show that the energy per unit length of lightning strikes within quartz sand has a geometric mean of ~1.0 MJ/m, and that the distribution is lognormal with respect to energy per …


Developing Priority Variables (“Ecosystem Essential Ocean Variables” — Eeovs) For Observing Dynamics And Change In Southern Ocean Ecosystems, Andrew J. Constable, Daniel P. Costa, Oscar Schofield, Louise Newman, Edward R. Urban Jr., Elizabeth A. Fulton, Jessica Melbourne-Thomas, Tosca Ballerini, Philip W. Boyd, Angelika Brandt, Eileen E. Hofmann Jan 2016

Developing Priority Variables (“Ecosystem Essential Ocean Variables” — Eeovs) For Observing Dynamics And Change In Southern Ocean Ecosystems, Andrew J. Constable, Daniel P. Costa, Oscar Schofield, Louise Newman, Edward R. Urban Jr., Elizabeth A. Fulton, Jessica Melbourne-Thomas, Tosca Ballerini, Philip W. Boyd, Angelika Brandt, Eileen E. Hofmann

CCPO Publications

Reliable statements about variability and change in marine ecosystems and their underlying causes are needed to report on their status and to guide management. Here we use the Framework on Ocean Observing (FOO) to begin developing ecosystem Essential Ocean Variables (eEOVs) for the Southern Ocean Observing System (SOOS). An eEOV is a defined biological or ecological quantity, which is derived from field observations, and which contributes significantly to assessments of Southern Ocean ecosystems. Here, assessments are concerned with estimating status and trends in ecosystem properties, attribution of trends to causes, and predicting future trajectories. eEOVs should be feasible to collect …


Effects Of Chemical Amendments To Swine Manure On Runoff Quality, Elizabeth L. Bullock, Dwayne R. Edwards, Phillip A. Moore Jr., Richard S. Gates Jan 2016

Effects Of Chemical Amendments To Swine Manure On Runoff Quality, Elizabeth L. Bullock, Dwayne R. Edwards, Phillip A. Moore Jr., Richard S. Gates

Biosystems and Agricultural Engineering Faculty Publications

Land-applied swine manure can be an environmental concern when runoff losses of manure constituents occur. The use of chemical amendments to mitigate these losses has been investigated for poultry litter, but materials such as swine manure have received less attention in this context, particularly at the plot scale or larger. The objective of this experiment was to evaluate the impacts of aluminum sulfate (alum; Al2(SO4)3), aluminum chloride (AlCl3), and ferric chloride (FeCl3) addition on runoff of selected constituents of land-applied swine manure. Manure was collected from feeder pigs fed a …


Measurement Of Antioxidant Activity Toward Superoxide In Natural Waters, D. Whitney King, Emma Berger, Zachary Helm, Eleanor Irish, Kenneth Mopper Jan 2016

Measurement Of Antioxidant Activity Toward Superoxide In Natural Waters, D. Whitney King, Emma Berger, Zachary Helm, Eleanor Irish, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

Antioxidants are a class of molecules that provide a protective function against reactive oxygen species (ROS) in biological systems by out competing physiologically important molecules for ROS oxidation. In natural waters, the reactivity of antioxidants gives an estimate of oxidative stress, and may determine the reactivity and distribution of reactive oxidants. We present an analytical method to measure antioxidant activity in natural waters through the competition between ascorbic acid, an antioxidant, and MCLA, a chemiluminescent probe for superoxide. A numerical kinetic model of the analytical method has been developed to optimize analytical performance. Measurements of antioxidant concentrations in pure and …


Effects Of Hydrology On The Growth And Recruitment Of Stream Fish In The Eastern Broadleaf Province Of Minnesota, Eric J. Krumm Jan 2016

Effects Of Hydrology On The Growth And Recruitment Of Stream Fish In The Eastern Broadleaf Province Of Minnesota, Eric J. Krumm

All Graduate Theses, Dissertations, and Other Capstone Projects

Agricultural practices and urban development have altered streamflows within the Eastern Broadleaf Province of Minnesota. Stream-flow alteration can produce significant changes in native freshwater communities. Therefore, knowledge of streamflow effects on representative freshwater populations and communities within the province are needed to maintain ecological integrity. Fish community and population dynamics often display predictable responses to flow regimes, which can make fishes model organisms for examining flow-ecology relationships.

In lotic systems, annual variation in streamflow can influence the annual growth and recruitment of fishes. Understanding the growth and recruitment of fish populations is essential for management and conservation efforts. Growth can …


Global And Regional Assessments Of Unsustainable Groundwater Use In Irrigated Agriculture, Danielle S. Grogan Jan 2016

Global And Regional Assessments Of Unsustainable Groundwater Use In Irrigated Agriculture, Danielle S. Grogan

Doctoral Dissertations

Groundwater is an essential input to agriculture world-wide, but it is clear that current rates of groundwater use are unsustainable in the long term. This dissertation assesses both current use of groundwater for country- to global-scale agriculture, and looks at the future of groundwater. The focus is on 1) quantifying food directly produced as a result of groundwater use across spatially-varying agricultural systems, 2) projecting future groundwater demands with consideration of climate change and human decision-making, and 3) understanding the system dynamics of groundwater re-use through surface water systems. All three are addressed using a process-based model designed to simulate …


Comparison Between Natural Radioactivity Levels Andgeochemistry Of Some Granitoids In Western Turkey, Si̇bel Tatar Erkül, Süleyman Fati̇h Özmen, Fuat Erkül, İsmai̇l Boztosun Jan 2016

Comparison Between Natural Radioactivity Levels Andgeochemistry Of Some Granitoids In Western Turkey, Si̇bel Tatar Erkül, Süleyman Fati̇h Özmen, Fuat Erkül, İsmai̇l Boztosun

Turkish Journal of Earth Sciences

Granitoids commonly include K-feldspar, biotite and zircon, apatite, titanite, allanite, and xenotime crystals, which are known to contain common radioactive elements. Radioactive isotopes of 40K, 238U, and 232Th can be harmful to human health with increasing dosage and their quantification should be well defined to assess the suitability of wall-rock granitoids for indoor and outdoor purposes. In this study, it is aimed to correlate the possible relationship between concentrations of natural radionuclides and SiO2, Na2O, K2O, and CaO together with elements U, Th, Zr, Y, Ba, Rb, and Sr to provide a basic approach to the compatibility of geochemical data …


A Geochronological And Stratigraphic Reconstruction Of The Middle Barataria Bay Receiving Basin, Joseph Ethan Thomas Hughes Jan 2016

A Geochronological And Stratigraphic Reconstruction Of The Middle Barataria Bay Receiving Basin, Joseph Ethan Thomas Hughes

LSU Master's Theses

Barataria Bay, one of the largest receiving basins for the Mississippi deltaic complex, is the location of a proposed river-sediment diversion for delta restoration. In order to determine how the sediment in the receiving-basin may respond to diversion flows, twenty-five sediment vibracores were collected from a 115 km2 study area located near Myrtle Grove and Bayou Dupont, southeast of New Orleans, LA. These cores were subject to multiple tests, including gamma bulk density scans, grain size analysis, and loss-on-ignition, in order to identify the lithology and stratigraphy. In addition, 137Cs and 14C dating techniques were employed in order to construct …


The Role Of Amino Acids In The Nitrogen Cycle Of Peatlands, Tia Scarpelli Jan 2016

The Role Of Amino Acids In The Nitrogen Cycle Of Peatlands, Tia Scarpelli

Dissertations, Master's Theses and Master's Reports

Future release of carbon from peatlands in response to climate change may be impacted by nitrogen limitation. The current study considers the role of amino acids as a nitrogen source in peatlands. The total free amino acid (TFAA) concentration for peats ranged from 0-2.3 µM, and leucine was the primary contributor. The dominance of sedge or ericaceous shrub plant types did not significantly impact the TFAA pool. Ammonium concentrations were much greater than TFAA and nitrate concentrations. TFAA concentrations were greatest in spring and least in fall. The springtime maxima and summer decrease in concentrations were simulated in a modeling …


Modern And Fossil Callianassid Burrows Of The Bahamas: Comparisons And Implications For Paleoenvironmental Analysis, H. Allen Curran, Koji Seike Jan 2016

Modern And Fossil Callianassid Burrows Of The Bahamas: Comparisons And Implications For Paleoenvironmental Analysis, H. Allen Curran, Koji Seike

Geosciences: Faculty Publications

Reprinted from: Bosiljka Glumac & Michael Savarese (eds.), Proceedings of the 16th Symposium on the Geology of the Bahamas and Other Carbonate Regions:San Salvador, Gerace Research Center


Partitioning Evapotranspiration In Forested Peatlands Within The Western Boreal Plain, Fort Mcmurray, Alberta, Canada, Elise C. Gabrielli Jan 2016

Partitioning Evapotranspiration In Forested Peatlands Within The Western Boreal Plain, Fort Mcmurray, Alberta, Canada, Elise C. Gabrielli

Theses and Dissertations (Comprehensive)

Forested peatlands in the Western Boreal Plain (WBP) represent hydrologically sensitive ecosystems that often support an open-crown forest of Picea mariana and/or Larix laricina. These systems store globally significant soil carbon, containing one-fourth to one-third of the world’s soil organic carbon pool (Turunen et al., 2002),serving a critical role in regulating atmospheric CO2. Recent studies indicate that the hydrological conditions are the critical determinant of a peatland’s carbon budget (Price et al., 2005; Aurela et al., 2007).To understand current hydrological conditions, it is essential to accurately estimate the rate of ET, due …


The Role Of Organic Matter In The Surface Chemistry Of Arsenic Compounds On Iron−(Oxyhydr)Oxides Studied By Atr-Ftir, Arthur Situm Jan 2016

The Role Of Organic Matter In The Surface Chemistry Of Arsenic Compounds On Iron−(Oxyhydr)Oxides Studied By Atr-Ftir, Arthur Situm

Theses and Dissertations (Comprehensive)

The interaction of organic matter with the interfaces of active soil components such as iron oxides is ubiquitous within soil environments. The presence of organics at these interfaces may have implications for other soil constituents whose mobility is controlled by their ability to bind to active soil components. Most of the studies performed to date which look at these interactions are bulk/batch studies performed ex-situ. Attenuated total internal reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was utilized within this work to study interactions between select model organics (citrate, oxalate and pyrocatechol) and iron−(oxyhydr)oxides, as well as their effect on the surface …


Evaluating The Biogeochemical Functioning Of A Constructed Fen On The Post-Mining Landscape Of Athabasca Oil Sands Region, Fort Mcmurray, Alberta, Canada, Felix C. Nwaishi Jan 2016

Evaluating The Biogeochemical Functioning Of A Constructed Fen On The Post-Mining Landscape Of Athabasca Oil Sands Region, Fort Mcmurray, Alberta, Canada, Felix C. Nwaishi

Theses and Dissertations (Comprehensive)

Peatlands have a unique biogeochemical function, characterized by an imbalance between the rates of biomass accumulation and decomposition. These characteristics facilitate the ability of peatlands to support the sequestration of nutrients and carbon. In disturbed peatlands, these functions are compromised. Thus, reclamation targets amongst other key functions, the recovery of biogeochemical functioning. These functions could serve as a measure of recovery to conditions that are present in natural analogues. This thesis examines the recovery of microbially-mediated nutrient transformation processes in a fen peatland that was constructed on a post-mining landscape in the Athabasca oil sands region, Fort McMurray, Alberta. The …


Spanish River Carbonatite: Its Benefits And Potential Use As A Soil Supplement In Agriculture, James J Jan 2016

Spanish River Carbonatite: Its Benefits And Potential Use As A Soil Supplement In Agriculture, James J

Theses and Dissertations (Comprehensive)

A critical problem facing agriculture today is being able to consistently and sustainably provide plants with adequate nutrients for growth. With this problem being exacerbated by the ever-increasing human population, new perspectives and techniques are required to ensure global food security. In order to fully realize potential solutions, however, plant growth and nutrition cannot be exclusively focused upon. The soil-microorganism-plant system is comprised of many interconnected and interdependent processes that together support plant growth: it is upon these processes that the focus must be placed. In this work, the agromineral Spanish River Carbonatite (SRC) is characterized using the framework of …


Paleoenvironmental Analysis Of Cretaceous Mudstones At Slope Mountain, Alaska Using Carbon Stable Isotopes, Ashley Ratigan Jan 2016

Paleoenvironmental Analysis Of Cretaceous Mudstones At Slope Mountain, Alaska Using Carbon Stable Isotopes, Ashley Ratigan

Honors Papers

This project uses field samples, microfacies analysis, and carbon stable isotopes of mudstones to determine past environmental conditions of North Slope, Alaska during the Albian-Cenomanian (Cretaceous). Samples were taken at Slope Mountain, Alaska located north of the Brooks Range. Slope Mountain includes the Torok Formation and the upper and lower Nanushuk Formations that consist of alluvial, deltaic, and shallow marine facies that were deposited into the North Slope foreland basin on the Arctic Alaska micro plate. An exhaustive search for identifiable microfossils, such as pollen, diatoms, and foraminifera in the samples yielded nothing but charcoal and carbon residue. No other …


High-Resolution Ground-Penetrating Radar Profiles Of Perennial Lake Ice In The Mcmurdo Dry Valleys, Antarctica: Horizon Attributes, Unconformities, And Subbottom, Hilary A. Dugan, Steven A. Arcone, Maciej K. Obryk, Peter T. Doran Jan 2016

High-Resolution Ground-Penetrating Radar Profiles Of Perennial Lake Ice In The Mcmurdo Dry Valleys, Antarctica: Horizon Attributes, Unconformities, And Subbottom, Hilary A. Dugan, Steven A. Arcone, Maciej K. Obryk, Peter T. Doran

Geology Faculty Publications and Presentations

Ground-penetrating radar (GPR) is not commonly used to study lake ice, and in general, the ground-based use of radar frequencies greater than 500 MHz in cryosphere geophysics is rare, due to a general interest in deeper stratigraphy and the difficulty of extensive profiling over rough snow surfaces. Our goal was to find further information on the origin of the deposition and formation of intra-ice layers, bottom topography, and subbottom deposits using GPR with pulses centered near 850 MHz on two permanently ice-covered lakes in the Mc- Murdo Dry Valleys, Antarctica. The profiles were obtained using a one-person sled operation over …


Response Of Antarctic Cryoconite Microbial Communities To Light, Elizabeth A. Bagshaw, Jemma L. Wadham, Martyn Tranter, Rupert Perkins, Alistair Morgan, Christopher J. Williamson, Andrew G. Fountain, Sean Fitzsimons, Ashley Dubnick Jan 2016

Response Of Antarctic Cryoconite Microbial Communities To Light, Elizabeth A. Bagshaw, Jemma L. Wadham, Martyn Tranter, Rupert Perkins, Alistair Morgan, Christopher J. Williamson, Andrew G. Fountain, Sean Fitzsimons, Ashley Dubnick

Geology Faculty Publications and Presentations

Microbial communities on polar glacier surfaces are found dispersed on the ice surface, or concentrated in cryoconite holes and cryolakes, which are accumulations of debris covered by a layer of ice for some or all of the year. The ice lid limits the penetration of photosynthetically available radiation (PAR) to the sediment layer, since the ice attenuates up to 99% of incoming radiation. This suite of field and laboratory experiments demonstrates that PAR is an important control on primary production in cryoconite and cryolake ecosystems. Increased light intensity increased efficiency of primary production in controlled laboratory incubations of debris from …