Digital Commons Network^™

Academic Specialties In U.S. Are Shifting; Hiring Of Women Geoscientists Is Stagnating, Mary Anne Holmes, Suzanne O'Connell, Connie Frey, Lois K. Ongley

Department of Earth and Atmospheric Sciences: Faculty Publications

Women have been receiving a greater proportion of the bachelor’s and master’s degrees in the geosciences over the last 10 years, reaching near 40% in 2000 (latest data available), while receiving only 28% of the Ph.D.s that year. Women are now only 20% of assistant professors at Ph.D.-granting institutions, a proportion that has not changed in the last four years. As part of a larger study to find what key barriers continue to prevent larger numbers of women geoscientists from becoming academics, data have been compiled from the National Science Board [NSB, 2002], and the American Geological Instititute's (AGI) Directory …

Dissolved Humic Substances: Characterization Of Their Sorption Onto Iron Hydroxide Aluminum Hydroxide Kaolinite And Smectite, Sarah E. Diebel

OES Theses and Dissertations

Humic (HA) and fulvic (FA) acids participate in many geochemical processes and the mechanisms of their sorption to colloidal surfaces are numerous, indicating these substances are complex and heterogeneous. The current study focuses on the interactions of the Fe hydroxide (FE), Al hydroxide, Kaolinite (KA) and Smectite (SM) and these naturally occurring organic acids using Fourier Transform Infrared Spectroscopy (FTIR) and DOC analysis at pH 4. FTIR was used for the initial functional group characterization, as well as the comparison of before and after adsorption spectra of the HA and FA. DOC examined the amounts of HA and FA adsorbed …

Spatial And Temporal Variability In The Amount And Source Of Dissolved Organic Carbon: Implications For Ultraviolet Exposure In Amphibian Habitats, Paul D. Brooks, Catherine M. O'Reilly, Stephen A. Diamond, Don H. Campbell, Roland Knapp, David Bradford, Paul Stephen Corn, Blake Hossack, Kathy Tonnessen

United States Geological Survey: Staff Publications

The amount, chemical composition, and source of dissolved organic carbon (DOC), together with in situ ultraviolet (UV-B) attenuation, were measured at 1–2 week intervals throughout the summers of 1999, 2000, and 2001 at four sites in Rocky Mountain National Park (Colorado). Eight additional sites, four in Sequoia and Kings Canyon National Park/John Muir Wilderness (California) and four in Glacier National Park (Montana), were sampled during the summer of 2000. Attenuation of UV-B was significantly related to DOC concentrations over the three years in Rocky Mountain (R² = 0.39, F = 25.71, P < 0.0001) and across all parks in 2000 (R² = 0.44, F = 38.25, P …

Sheep Updates 2003 - Pastures, Ed Barrett-Lennard, Hayley Norman, Robyn Dynes, David Masters, David Henry, Stephen Gherardi, Graham Donald, Asoka Edirisinghe, Chris Oldham, Richard Smith, Joanne Sneddon, Mike Hyder, Andrew Thompson, Kazue Tanaka, Roy Latta, Chris Matthews, Brad Nutt, Angela Loi, Tim Wiley

Sheep Updates

This session covers seven papers from different authors: 1. Pastures for saline land, Ed Barrett-Lennard 1Department of Agriculture, Western Australia, Hayley Norman, Robyn Dynes and David Masters CSIRO Livestock Industries, Centre for Mediterranean Agricultural Research, Floreat Park, 2. Feeding value - the essential link between pastures and animals CSIRO Livestock Industries, Centre for Environmental and Life Sciences 3. ‘Pastures from space’ - how do we do it, how well do we do it and what do producers think about it? Stephen Gherardi Department of Agriculture Western Australia Graham Donald Asoka Edirisinghe Dave Henry CSIRO Livestock Industries Chris Oldham Department of …

Application Of Geochemical Fingerprinting And Isotopes To Identity Landfill Gas Impacts To Groundwater, Eric E. Wallis

Masters Theses

Volatile organic compounds (VOCs) are detected in two groundwater monitoring wells (MW-60 and MW-62S) located along the northern, downgradient property line of the McGill Road Landfill (MRL) in Jackson, Michigan. Potential on-site sources for groundwater impact are two distinct landfill units at the MRL. Leachate chemistry suggested that landfill leachate was not the source of VOCs detected in groundwater. A potential source for VOCs was landfill gas. Sources of landfill gas in the vicinity of the impacted wells included the distinct MRL landfill units as well as the old Jackson County Landfill (JCL), located hydraulically downgradient from the impacted wells. …

Landscape Change In The Southern Piedmont: Challenges, Solutions, And Uncertainty Across Scales, Michael J. Conroy, Craig R. Allen, James T. Peterson, Lowell Pritchard, Clinton T. Moore

United States Geological Survey: Staff Publications

The southern Piedmont of the southeastern United States epitomizes the complex and seemingly intractable problems and hard decisions that result from uncontrolled urban and suburban sprawl. Here we consider three recurrent themes in complicated problems involving complex systems: (1) scale dependencies and cross-scale, often nonlinear relationships; (2) resilience, in particular the potential for complex systems to move to alternate stable states with decreased ecological and/or economic value; and (3) uncertainty in the ability to understand and predict outcomes, perhaps particularly those that occur as a result of human impacts. We consider these issues in the context of landscape-level decision making, …

Levels Of Pesticide Residues In Water, Soil And Sediments From Southern Lake Victoria And Its Basin, Leonia Henry, Michale A Kishimba

Tanzania Journal of Science

Water, sediment and soil samples collected from Southern Lake Victoria and its basin were analysed for 76 organochlorine, organophosphorous, carbamate and pyrethroid pesticide residues. The samples were collected from sampling stations in nine districts on the Tanzanian side of the lake, namely Mwanza, Sengerema, Geita, Ngudu, Misungwi, Magu, Bunda, Tarime and Musoma Districts. DDT and HCH residues were the only detected pesticides. The concentration of total DDT was up to 1.6 mg/L in water, 600 mg/kg dry mass in sediments and 20 mg/kg dry mass in soil. The concentration of total HCHs were up to 0.2 mg/L in water, 132 …

Isolation And Characterization Of Thermophilic, Calcium-Precipitating Bacteria Form Calcite Deposits At Yucca Mountain, Terry Ann Else, Curtis R. Pantle, Penny S. Amy, Mark P. Buttner, Amy J. Smiecinski

Publications (YM)

Calcite deposits, composed of a mixture of calcium carbonate and silicon dioxide, were found in fractures and small cavities within the welded tuff of Yucca Mountain. This research investigation involves determining the presence of thermophilic, calciumprecipitating bacteria within these deposits. The possible existence of thermophilic bacteria may help to resolve the issue of whether these calcite deposits formed from precipitation of dissolved calcium carbonate in rain water transported from the overlying soil environment or as a result of upwelling of geothermally-heated waters transported from below the mountain. Evidence for microbially-influenced calcite precipitation in these deposits is indicated by the presence …

East Mortlock : Catchment Appraisal 2002, Don Cummins

Resource management technical reports

This report describes the soils, hydrology, natural vegetation and farming systems of the East Mortlock catchment and provides information on the threats to agriculture, infrastructure and natural resources caused by land degradation. East Mortlock covers over 800,000 hectares in the central wheatbelt. Rapid Catchment Appraisal aims to document salinity risk and management options by addressing all threats to the natural resource base, rather than isolating salinity as a separate issue.

Hydrogeologic Principles Useful In Predicting The Effects Of Stream Flow Alterations On Shallow Groundwater And Associated Riparian Vegetation, Mark Cable Rains

Geology Faculty Publications

Numerous studies have shown that stream water and shallow groundwater are tightly linked in alluvial settings, and that changes in stream stage are propagated rapidly across alluvial aquifers (Castro and Hornberger 1991, Sophocleous 1991). Thus, many researchers have assumed that stream stages approximate water tables in alluvial aquifers (Auble et al. 1994, Stromberg and Patten 1996). This assumption is valid in some cases but invalid in other cases, particularly in arid basin terrain and more humid mountain terrain. Even when this assumption is valid, this relationship only implies correlation and not causation so the potential effects of stream flow alterations …

Characterization Of Environmentally Friendly Polymers: Amylopectin And Its Blends, Mohammad Osman Melibari

Theses and Dissertations

Biodegradable polymers are desirable for a variety of applications, such as in packaging, agriculture, and medicine. Its biological degradation by microorganisms accelerated the interest in biodegradable polymers during the last decades. Within this group of innovative environmentally friendly biodegradable polymers, starch or Amylpectin plays a predominant role, due to their potential biodegradability. This research was attempted to characterize Amylopectin to obtain its physio-chemical properties. In addition, characterizations were extended to include blends of Amylopectin and biodegradable diluents. Blends of Amylopectin with biodegradable diluents including Polycaprolactone, Poly(DL-lactide-co-glycolide), and Poly(3- hydroxybutyric acid) were prepared. The physical properties and the thermodynamic characteristics of …

Organization Of The Devils Hole Workshop, Irene Farnham

Publications (YM)

The Harry Reid Center for Environmental Studies (HRC) at the University of Nevada, Las Vegas (UNLV) was tasked to organize the Devils Hole Workshop in Furnace Creek Death Valley, CA on May 21 – 23, 2003. This Conference is designed to report current research results and to bring the scientific community, as well as the general public, up to date on research relevant to the Death Valley Regional Flow System (DVRFS). The Devils Hole Workshop is beneficial to the DOE because it provides the opportunity to DOE technical task leaders and Bechtel SAIC (BSC) representatives to present the research currently …

Ashfall Historic Park: Field Trip 5, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Ashfall Fossill Beds: A State Historical Park. Brochure. Nebraska Game and Parks Commission and University of Nebraska State Museum

Research Reports, 1978. Projects: A Miocene Rhinoceros Herd Buried in Volcanic Ash. Grant Recipient: Michael R. Voorhies, Division of Vertebrate Paleontology, University of Nebraska State Museum, Lincoln, Nebraska.

Geologic Framework of the Niobrara River Drainage Basin and Adjacent Areas in South Dakota Generally East of the 100th Meridian West Longitude and West of the Missouri River Robert F. Diffendal, Jr. and Michael R. Voorhies. Nebraska Geological Survey Report of Investigations, number 9.

Investigating The Geoelectrical Response Of Hydrocarbon Contamination Undergoing Biodegradation, D. Dale Werkema, Estella A. Atekwana, Anthony L. Endres, William August Sauck, Daniel P. Cassidy

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

A newly proposed geoelectrical model for hydrocarbon contaminated sites predicts high conductivities coincident with the contaminated zone as opposed to the traditionally accepted low conductivity. The model attributes the high conductivities to mineral weathering resulting from byproducts of microbial redox processes. To evaluate this conductive model, in situ vertical conductivity measurements were acquired from a light non-aqueous phase liquid (LNAPL) contaminated site. The results showed high conductivities coincident with the zone of contamination and within the smear zone influenced by seasonal water table fluctuations. We infer this zone as an active zone of biodegradation and suggest significant microbial degradation under …

Morphological Biosignatures And The Search For Life On Mars, Sherry L. Cady, Jack D. Farmer, John P. Grotzinger, J. William Schopf, Andrew Steele

Geology Faculty Publications and Presentations

This report provides a rationale for the advances in instrumentation and understanding needed to assess claims of ancient and extraterrestrial life made on the basis of morphological biosignatures. Morphological biosignatures consist of bona fide microbial fossils as well as microbially influenced sedimentary structures. To be recognized as evidence of life, microbial fossils must contain chemical and structural attributes uniquely indicative of microbial cells or cellular or extracellular processes. When combined with various research strategies, high-resolution instruments can reveal such attributes and elucidate how morphological fossils form and become altered, thereby improving the ability to recognize them in the geological record …

Melting Processes And Fluid And Sediment Transport Rates Along The Alaska-Aleutian Arc From An Integrated U-Th-Ra-Be Isotope Study, Rhiannon George, Simon Turner, Chris Hawkesworth, Julie Morris, Chris Nye, Jeffrey G. Ryan, Shu-Hui Zheng

Geology Faculty Publications

A comprehensive data set for young lavas erupted along the Alaska-Aleutian arc is used to examine how fluid and sediment transport rates and melting processes vary in response to systematic changes in subduction rate and dip along the arc and across the ocean-continent boundary. Positive correlations between convergence rate, volcano volume, and ²³⁸U excesses suggest that magmatic output is closely linked to the size of the fluid flux which occurred <10 kyr prior to eruption. Sediment-sensitive tracers like Th/Nb, Ce/Ce*, and ¹⁰Be/⁹Be also increase with convergence rate. However, the inferred ¹⁰Be/⁹Be ratio of this component is low relative to that in the incoming sediments, …

A Vegetation And Fire History Of Lake Titicaca Since The Last Glacial Maximum, Gina M. Paduano, Mark B. Bush, Paul A. Baker, Sherilyn C. Fritz, Geoffrey O. Seltzer

Department of Earth and Atmospheric Sciences: Faculty Publications

Fine-resolution fossil pollen and charcoal analyses reconstruct a vegetation and fire history in the area surrounding Lake Titicaca (3810 m, Peru/Bolivia) since ca. 27,500 cal yr BP (hereafter BP). Time control was based on 26 accelerator mass spectrometer (AMS) radiocarbon dates. Seventeen AMS dates and 155 pollen and charcoal samples between ca. 17,500 BP and ca. 3,100 BP allow a centennial-scale reconstruction of deglacial and early- to mid-Holocene events. Local and regional fire signals were based on the separation of two charcoal size fractions, ≥180 μm and 179–65 μm. Charcoal abundance correlated closely with the proportion of woody taxa present …

Analysis Of The Effects Of Hypogeal And Epigeal Emergence On Seedling Competition In Legumes, Keith E. King

McCabe Thesis Collection

Seedling emergence is either hypogeal or epigeal. In hypogeal emergence the cotyledons remain below the soil surface during seedling development, while in epigeal emergence the cotyledons extend above the soil surface due to elongation of the hypocotyl. Here we examine the effect of seed size, and emergence type, on seedling growth. Six legumes with variation in seed size and either epigeal or hypogeal emergence were grown under dark and light conditions. A competition study was also conducted where a hypogeal and epigeal legume were grown in combination with wheat and ryegrass. Legumes expressing epigeal emergence were cowpea (Vigna unguiculata), mung …

West Mortlock Catchment Appraisal 2002, D G. Cummins

Resource management technical reports

This report describes the soils, hydrology, natural vegetation and farming systems of the West Mortlock catchment and provides information on the threats to agriculture, infrastructure and natural resources caused by land degradation. West Mortlock covers over 700,000 hectares in the central wheatbelt. Rapid Catchment Appraisal aims to document salinity risk and management options by addressing all threats to the natural resource base, rather than isolating salinity as a separate issue.

Assessing Storage Reliability Of Farm Dams, D Farmer, N Coles

Resource management technical reports

This report provides information on a method to estimate the volume of water in a farm dam and to determine how long this water will last. During periods of low rainfall, dams with farmland catchments receive limited run-off. Alternative water sources or management strategies need to be considered before the water runs out. The methods provided in this report are intended to provide to the landholder an indication of water supply over short periods only (i.e. in the order of 4-20 weeks).

Mercury Concentrations In Streams Of East Texas, Mingteh Chang, Mark C. Cochran, R. Scott Beasley, Matthew W. Mcbroom

Faculty Publications

Recent studies on potential mercury (Hg) contamination of fish from East Texas lakes and waterways have caused concern about mercury levels in East Texas waters. Historical records of Hg concentrations in 33 East Texas streams showed that median concentrations for each stream segment were no different than other U.S. streams. All the means and medians for stream segments having at least 20 recorded measurements were less than Texas (2.4 µg/L) water quality standards. Water samples collected in December 1995 and March 1996 from 6 different stream sites in Nacogdoches County had concentrations similar to historical records. Due to biological magnification, …

Quaternary Geology And Landscape Evolution Of Eastern Grand Canyon, Arizona, Matt D. Anders

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tectonics and drainage evolution are controlling overall landscape incision in eastern Grand Canyon. Superimposed on downcutting are dynamic responses of hillslopes, tributary streams, and the Colorado River to glacial-interglacial climate cycles. Five tributary stream fill terraces have been identified, and luminescence dating indicates aggradation was occurring 50- 34 ka {S3), 12-7 ka (S2), and 5-3.5 ka (S1). Seven Colorado River fill terraces have been identified, and luminescence and U-series dating indicate deposition was occurring 343-322 ka (M5), 151-118 ka (M4), and 71-64 ka (M3).

Aggradation by the Colorado River in eastern Grand Canyon begins during glacial advances and continues into …

Remotely Forced Nearshore Upwelling In Southern California, James M. Pringle, K Riser

Earth Sciences

[1] Alongshore winds in Baja California strongly influence nearshore temperatures hundreds of kilometers to the north at Point Loma, San Diego, California, on timescales of a week to a year. The time lag between wind and temperature is consistent with first mode coastal trapped wave phase speed. The nearshore cross-shelf circulation forced by the coastal trapped waves is, at least much of the year, oppositely directed at the surface and bottom. No relation is found between the winds and temperature for periods greater than a year. It is argued that similar results may be found elsewhere in the Southern California …

Depositional Characteristics Of 7Be And 210Pb In Southeastern Michigan, D. Mcneary, M. Baskaran

Environmental Science and Geology Faculty Research Publications

The depositional fluxes in the bulk and dry fallout as well as the concentrations of ⁷Be and ²¹⁰Pb in aerosols were measured for a period of 17 months at Detroit, Michigan. The bulk depositional fluxes of ⁷Be and ²¹⁰Pb varied between 3.11 and 63.0 dpm cm⁻² yr⁻¹ (mean of 11.4 dpm cm⁻² yr⁻¹) and 0.35 and 10.3 dpm cm⁻² yr⁻¹ (mean of 1.41 dpm cm⁻² yr⁻¹), respectively, and this variability in the depositional fluxes is attributed to the frequency and amount of precipitation and seasonal variations …

A Geochemical Survey Of The Natural Waters Of Belize, Central America, Anthony D. Marfia

Masters Theses

A geochemical survey of the natural waters in Belize, Central America was carried out to compliment routine water quality analysis and to identify processes affecting water quality. The objective of this research was to provide a geochemical assessment of natural waters throughout Belize by examining select major ions (Ca²⁺, Mg²⁺ , SO₄^2-), and stable isotopes of carbon (¹³C), oxygen (¹⁸O) and hydrogen (²H).

The dominant geology relevant to this investigation comprises a varied landscape of carbonates and elastic sediments in a subtropical rainforest/savannah climate. Stable oxygen and hydrogen …

Influence Of A Cyclonic Eddy On Microheterotroph Biomass And Carbon Export In The Lee Of Hawaii, Robert R. Bidigare, Claudia R. Benitez-Nelson, Carrie L. Leonard, Paul D. Quay, Michael L. Parsons, David G. Foley, Michael P. Seki

Faculty Publications

[1] A multi‐platform sampling strategy was used to investigate carbon cycling in a cold‐core eddy that formed in the lee of Hawaii during September 2000. Microheterotroph biomass and 234Th‐derived carbon export rates within the eddy were 2 to 3 times higher than those observed for adjacent waters. If this eddy is representative of other cyclonic eddies that are frequently formed in the lee of Hawaii, then eddy activity may significantly enhance the areal efficiency of the biological pump and facilitate the transfer of organic carbon to organisms inhabiting the mesopelagic and abyssal‐benthic zones of this subtropical ecosystem.

The Development Of Relationships Between Constituent Concentrations And Generic Hydrological Variables, Carmen T. Agouridis, Dwayne R. Edwards

Biosystems and Agricultural Engineering Faculty Publications

The collection and analysis of samples from storm events constitutes a large portion of the effort associated with water quality research. Estimating concentrations or loads from these events is often difficult. The equipment necessary to analyze the samples and the required laboratory resources are typically significant expenses incurred by the researcher. One potential method to reduce these costs is through the development of generic relationships between concentrations and easily measured variables such as dimensionless flow rate or time. The benefits recognized from such an effort include a reduction in the number of required samples, resulting in a reduction in cost. …

Water-Quality Assessment Of The Central Nebraska Basins-— Enering A New Decade, Ronald B. Zelt, Jill D. Frankforter

United States Geological Survey: Publications

In 2001, the U.S. Geological Survey’s (USGS) National Water- Quality Assessment (NAWQA) Program began its second decade of intensive water-quality assessments (Cycle II). NAWQA scientists plan to revisit 42 major river-basin and aquifer systems (called study units) that were assessed in the first decade (Gilliom and others, 2001).

The Application Of A Diatom-Based Transfer Function To Evaluate Regional Water-Quality Trends In Minnesota Since 1970, J. M. Ramstack, Sherilyn C. Fritz, D. R. Engstrom, S. A. Heiskary

Department of Earth and Atmospheric Sciences: Faculty Publications

Significant population growth over the last three decades, as well as efforts to improve surface-water quality mandated by the Clean Water Act, potentially have had opposing influences on aquatic ecosystems in the U.S. Because historical data on water-quality trends are limited over this time period, we developed a diatom-based transfer function to reconstruct chloride, color, acid neutralizing capacity (ANC), total phosphorus (TP), and pH in 55 Minnesota lakes. The lakes span three different ecoregions, as well as the Twin Cities metropolitan area, and differ in their history of settlement and land use, and in surficial geology, climate, and vegetation. Lakes …

Vegetation Establishment For Erosion Control Under Simulated Rainfall, Brent G. Hallock, Misty Scharff, Steve Rein, Kaila Dettman

Earth and Soil Sciences

The California Department of Transportation (Caltrans) manages rights of ways that transect 41 m H (101m ac) and span over 3000 m (9000 ft) in elevation from seashore to sup alpine. There are approximately 4,900 native and 1,000 naturalized alien plant species in California. Only a few hundred are reliably useful in erosion and sediment control. Specifying native and naturalized vegetation mixes for use in hydroseeding or plug planting in conjunction with mechanical erosion control methods can have varying result for minimizing accelerated soil erosion. To investigate these factors, Cal Poly, San Luis Obispo, in conjunction with Caltrans and CSU, …