Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Earth Sciences

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 3121 - 3150 of 3654

Full-Text Articles in Entire DC Network

Lead In Birds, J. Christian Franson, Deborah J. Pain Jan 2011

Lead In Birds, J. Christian Franson, Deborah J. Pain

United States Geological Survey: Staff Publications

Lead is a highly toxic heavy metal that acts as a nonspecific poison affecting all body systems and has no known biological requirement. Absorption of low concentrations may result in a wide range of sublethal effects in animals, and higher concentrations may result in mortality (Demayo et al. 1982).

Lead has been mined and smelted by humans for centuries, but the use of lead-based products increased greatly following the Industrial Revolution. Consequently, lead today is ubiquitous in air, water, and soil, in both urban and rural environments (Eisler 2000). Vertebrates are exposed to lead mainly via inhalation and ingestion. A …


The Spatial Distribution Of Solar Radiation Under A Melting Arctic Sea Ice Cover, Karen E. Frey, Donald K. Perovich, Bonnie Light Jan 2011

The Spatial Distribution Of Solar Radiation Under A Melting Arctic Sea Ice Cover, Karen E. Frey, Donald K. Perovich, Bonnie Light

Geography

The sea ice cover of the Chukchi and Beaufort Seas is currently undergoing a fundamental shift from multiyear ice to first-year ice. Field observations of sea ice physical and optical properties were collected in this region during June-July 2010, revealing unexpectedly complex spatial distributions of solar radiation under the melt-season ice cover. Based on our optical measurements of first-year ice, we found the under-ice light field in the upper ocean to be spatially heterogeneous and dependent on wavelength, ice thickness, and the areal and geometric distribution of melt ponded and bare ice surfaces. Much of the observed complexity in radiation …


"The Need Obliged Us" : Culture As Capacity During The Hurricane Stan Emergency Response. A Case Study From Tectitan, Huehuetenango, Guatemala , Jesse Silverman Jan 2011

"The Need Obliged Us" : Culture As Capacity During The Hurricane Stan Emergency Response. A Case Study From Tectitan, Huehuetenango, Guatemala , Jesse Silverman

Dissertations, Master's Theses and Master's Reports - Open

A major deficiency in disaster management plans is the assumption that pre-disaster civil-society does not have the capacity to respond effectively during crises. Following from this assumption a dominant emergency management strategy is to replace weak civil-society organizations with specialized disaster organizations that are often either military or Para-military and seek to centralize decision-making. Many criticisms have been made of this approach, but few specifically addresses disasters in the developing world. Disasters in the developing world present unique problems not seen in the developed world because they often occur in the context of compromised governments, and marginalized populations. In this …


Fate Of Stable Isotope Label During Predation Of 15N-Tagged Wild-Type Escherichia Coli By Protozoa, Ashley M. Barton Jan 2011

Fate Of Stable Isotope Label During Predation Of 15N-Tagged Wild-Type Escherichia Coli By Protozoa, Ashley M. Barton

University of Kentucky Master's Theses

Currently, bacterial movement in karst aquifers is not well understood. Use of stable isotopes to label non-pathogenic Escherichia coli as a particulate groundwater tracer in karst systems has been examined in previous studies. Loss of the stable isotope signal is anticipated in traces greater than 500 m in length. Potential loss of 15N due to predation by protozoa was examined. Filter-sterilized water from Royal Spring in Georgetown, Kentucky, was inoculated with a mixture of either Tetrahymena pyriformis or Colpoda steinii and 15N-enriched E. coli and stored in the dark at 14°C. Samples were analyzed for their nitrogen isotope …


Implications Of Surface Runoff Recharge In Semi-Arid Regions On Groundwater Sustainability, Omar M. Al-Qudah Jan 2011

Implications Of Surface Runoff Recharge In Semi-Arid Regions On Groundwater Sustainability, Omar M. Al-Qudah

Open Access Theses & Dissertations

Amargosa Desert, Nevada regional groundwater studies show that the surface runoff infiltration occurring in the arroyos following runoff producing storms, and this infiltration is considered to be a major source of groundwater recharge. Groundwater infiltration through alluvium was investigated in the Amargosa Desert using borehole drill cuttings, groundwater chemistry, and applying a novel method for collecting runoff water. The sampling process included sediment, precipitation, and runoff water. In total, 176 runoff, 182 sediment, and 45 precipitation samples were collected between January, 2009 and January, 2011.Water chemistry, chloride concentrations, and stable isotopes of water collected from specially designed runoff samplers, placed …


The Green, Blue And Grey Water Footprint Of Farm Animals And Animal Products. Volume 1: Main Report, Mesfin Mekonnen, Arjen Y. Hoekstra Dec 2010

The Green, Blue And Grey Water Footprint Of Farm Animals And Animal Products. Volume 1: Main Report, Mesfin Mekonnen, Arjen Y. Hoekstra

Daugherty Water for Food Global Institute: Faculty Publications

The projected increase in the production and consumption of animal products is likely to put further pressure on the globe’s freshwater resources. The size and characteristics of the water footprint vary across animal types and production systems. The current study provides a comprehensive account of the global green, blue and grey water footprints of different sorts of farm animals and animal products, distinguishing between different production systems and considering the conditions in all countries of the world separately. The following animal categories were considered: beef cattle, dairy cattle, pig, sheep, goat, broiler chicken, layer chicken and horses. The study shows …


Farmers' Markets In Kentucky: A Geospatial, Statistical, And Cultural Analysis, Elizabeth Ann Schmitz Dec 2010

Farmers' Markets In Kentucky: A Geospatial, Statistical, And Cultural Analysis, Elizabeth Ann Schmitz

Masters Theses & Specialist Projects

To assess what factors are driving the exponential growth of farmers’ markets in Kentucky, geospatial and statistical analysis of a database of 121 farmers’ markets was conducted. A statewide survey of market leaders and a case study of a single farmers’ market both identified reasons for growing support of farmers’ markets in Kentucky.

Market distribution, vendor levels, and gross sales were mapped against a backdrop of county urban classification, median household income, and education levels. Kruskal-Wallace analysis was used to identify if Kentucky’s rural, micropolitan, and metropolitan markets differ significantly in terms of their age, number of vendors, and market …


Molecular Mechanisms Of Persistence Of Mutualistic Bacteria Photorhabdus In The Entomopathogenic Nematode Host, Ruisheng An, Parwinder Grewal Oct 2010

Molecular Mechanisms Of Persistence Of Mutualistic Bacteria Photorhabdus In The Entomopathogenic Nematode Host, Ruisheng An, Parwinder Grewal

School of Earth, Environmental, & Marine Sciences Faculty Publications

Symbioses between microbes and animals are ubiquitous, yet little is known about the intricate mechanisms maintaining such associations. In an emerging mutualistic model system, insect-pathogenic bacteria Photorhabdus and their insect-parasitic nematode partner Heterorhabditis, we found that the bacteria undergo major transcriptional reshaping in the nematode intestine. Besides general starvation mechanisms, the bacteria induce cellular acidification to slow down growth, switch to pentose phosphate pathway to overcome oxidative stress and nutrition limitation, and shed motility but develop biofilm to persist in the nematode intestine until being released into the insect hemolymph. These findings demonstrate how the symbiotic bacteria reduce their …


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


Phosphorus Uptake In Rhodomonas Salina (Wislouch) And Its Effect On Allocation And Elimination In Acartia Tonsa (Dana), Danna Palladino Oct 2010

Phosphorus Uptake In Rhodomonas Salina (Wislouch) And Its Effect On Allocation And Elimination In Acartia Tonsa (Dana), Danna Palladino

OES Theses and Dissertations

Phosphorus is a key element in important biochemical compounds, such as RNA and phospholipids, and can become limiting in a variety of marine systems. The uptake of phosphorus into biochemical fractions (protein, low molecular weight (LMW) compounds, lipid, polysaccharide and nucleic acid) in Acartia tonsa fed 33P -labeled Rhodomonas salina was examined. R. salina was cultured on two variations of one media that in one case contained phosphorus in balance and the other out of balance with relation to other standard f/2 components. The P-balanced (PB) media had a N:P ratio of 24.5, which is higher than that found …


Development Of Agroecology Based Garden System And Educational Program At Grand Valley State University, Kendall Gilbert, Edwin Joseph Oct 2010

Development Of Agroecology Based Garden System And Educational Program At Grand Valley State University, Kendall Gilbert, Edwin Joseph

Student Summer Scholars Manuscripts

This study was part of a twelve- week project to introduce agroecology growing principles and educational models at the Community Garden on the campus of Grand Valley State University in Allendale, Michigan. This project was set up to be a demonstration for the further development of the garden space as an area for agroecology focused education, extension, and outreach. To accomplish this, three areas of change became essential components to developing a garden space that can serve as a living laboratory, demonstration area, and outdoor classroom. The first project goal was to develop and create a demonstration garden plot that …


Simulation Of Contaminant Transport From Solid Domestic Waste Disposal Sites In The Warri Deltaic Plain Sands, Warri-Effurun, Nigeria, Charles Onoriode Usiaphre Aug 2010

Simulation Of Contaminant Transport From Solid Domestic Waste Disposal Sites In The Warri Deltaic Plain Sands, Warri-Effurun, Nigeria, Charles Onoriode Usiaphre

Theses, Dissertations and Culminating Projects

Protecting the groundwater resource in the Warri Deltaic Plain sand from the impact of anthropogenic contamination requires an understanding and knowledge of groundwater flow paths, transport processes and the source of contamination. This study was carried out to find out contaminant transport from solid domestic waste sites to the groundwater. The U.S. Geological Survey three-dimensional finite-difference code, MODFLOW, was used to simulate the groundwater flow. The flow pattern reveals predominantly downward flow, with major horizontal motion towards towns around Ekurede Urhobo and Ekurede Itsekiri in Warri. Simulation of advective contaminant transport using MODPATE1 for particle tracking indicates local movement of …


Management And Control Plan For Zinfandel Vines In South Paso Robles, Ca., Tanner E. Campbell Jun 2010

Management And Control Plan For Zinfandel Vines In South Paso Robles, Ca., Tanner E. Campbell

Earth and Soil Sciences

Zinfandel, also known as Zin, is a red skinned variety of wine grape very popular in California. The wines produced from Zinfandel grapes have an intense fruitiness and luscious texture. Production is extremely variable throughout California and is dependent upon, climate, soil fertility, crop level management practices, and irrigation. This study was conducted to determine the on site soil physical and chemical properties as a means to obtain optimal yields and fruit quality. The A & L Western Agriculture Laboratories performed comprehensive fertility analysis to determine the concentrations of the plant essential nutrients, organic matter, electrical conductivity, cation exchange capacity, …


Effects Of Recycled Water On Landscape Plants, Casey R. Miranda Jun 2010

Effects Of Recycled Water On Landscape Plants, Casey R. Miranda

Master's Theses

ABSTRACT EFFECTS OF RECYCLED WATER ON LANDSCAPE PLANTS Casey Ray Miranda Recycled water is water that has been previously used, has suffered a loss of quality, and has been properly treated for redistribution (Wu et al. 2001). The use of recycled water as an alternative to fresh water in the landscape can have positive and negative effects. Experimentation on 40 different plant species during a 32 week period (2 phases of 16 weeks), was conducted to analyze the effects of recycled water irrigation on the appearance of landscape plants. Each species of plant was planted into 10 individual number 2 …


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 …


A Study Of The Sustainability Of Wild Capture Salmon In The Pacific Northwest, Justin D. Hansen May 2010

A Study Of The Sustainability Of Wild Capture Salmon In The Pacific Northwest, Justin D. Hansen

Social Sciences

No abstract provided.


Investigations On Some Zeolitic Volcanic Tuffs From Cluj County (Romania), Used For Zinc Ions Removal From Aqueous Solution, Horea Bedelean, Andrada Maicaneanu, Silvia Burca, Maria Stanca Apr 2010

Investigations On Some Zeolitic Volcanic Tuffs From Cluj County (Romania), Used For Zinc Ions Removal From Aqueous Solution, Horea Bedelean, Andrada Maicaneanu, Silvia Burca, Maria Stanca

Studia UBB Geologia

Representative samples of zeolitic tuffs from Măcicaş, Aluniş and Apahida occurrences (Cluj County, Romania) were investigated using optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and wet chemical analyses. The studied tuffs samples are mainly represented by vitric and vitric crystal varieties. The mineral assemblage suggests a rhyo-dacitic petrographic type of the volcanic tuff. Diagenetic alteration process in the pyroclastic sequence from this region led to the formation of zeolites, mainly clinoptilolite. The zeolitic tuffs under study can be used in wastewaters treatment to remove Zn2+ ions. Zn2+ removal was performed on some bulk samples: Aluniş (labelled A1), Apahida …


Sustainable Portland: Implementation Series 3, New England Environmental Finance Center Apr 2010

Sustainable Portland: Implementation Series 3, New England Environmental Finance Center

Climate Change

This report is the third in a series of efforts by students at the Muskie School of Public Service, Community Planning and Development Master’s program, in a core class called “Sustainable Communities.” In this course students seek to understand principles of sustainability and how efforts to implement Sustainability programs can become more successful. The report assembles term papers students completed on particular efforts by municipalities, universities, and other groups to achieve sustainability goals. Students worked on each project in a service learning format with real world clients. They were asked to fashion their papers around lessons learned by other organizations …


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


Book Review Of James Lovelock: In Search Of Gaia, By John Gribbin And Mary Gribbin, Robert F. Diffendal Jr. Apr 2010

Book Review Of James Lovelock: In Search Of Gaia, By John Gribbin And Mary Gribbin, Robert F. Diffendal Jr.

Great Plains Research: A Journal of Natural and Social Sciences (through 2013)

My book review editor asked me what might be relevant to the Great Plains in a biography of James Lovelock, a book I’d suggested as worth reviewing in Great Plains Research. I assured him that much in it either is or should be relevant to the Great Plains and to science researchers working on studies of aspects of the Great Plains.

James Ephraim Lovelock, born on July 26, 1919, of fairly humble origins, did not do well in school, partly because he was dyslexic. In spite of this and other health problems over the years, he went on to …


Cellulosic Ethanol: The Benefits, Obstacles, And Implications For Nebraska, Cassidee Lin Thompson Apr 2010

Cellulosic Ethanol: The Benefits, Obstacles, And Implications For Nebraska, Cassidee Lin Thompson

Department of Environmental Studies: Undergraduate Student Theses

Abstract Ethanol is a biofuel that has unique capabilities to mitigate global climate change by reducing greenhouse gas emissions while simultaneously supporting rural economies and decreasing the United States’ dependence on foreign oil. Currently, the state of Nebraska depends on corn ethanol, which may be unsustainable. Cellulosic ethanol is a promising alternative but it is not without its problems, including high production costs and potential environmental damage. This thesis is an attempt to understand the benefits, downfalls, and processes of corn-based and cellulosic ethanol and the potential implications to Nebraska. This research should shed some light on the current obstacles …


Growing Alfalfa For Wildlife, Don Ball Feb 2010

Growing Alfalfa For Wildlife, Don Ball

Kentucky Alfalfa and Stored Forage Conference

Alfalfa has long been recognized as a superb forage crop, which is why it is widely grown for dairy cattle, horses, sheep, and many other types of domesticated forage-consuming animals. Reasons for its popularity include wide adaptation, excellent nutritive value, good yield potential, perennial growth habit, a long growing season, and the fact that (in association with Rhizobium bacteria) it is a nitrogen-fixing legume that does not require periodic applications of nitrogen fertilizer.


Alfalfa Varieties For The Future, Joe Bouton Feb 2010

Alfalfa Varieties For The Future, Joe Bouton

Kentucky Alfalfa and Stored Forage Conference

When breeding tomorrow’s alfalfa varieties, most groups employ a model of combining traditional plant breeding with biotechnology tools in order to incorporate useful traits. In this model, the conventional variety development process will be the method of choice for most traits where breeders have traditionally made progress such as adaptation, heading date, disease and insect resistance, general persistence conditions such as grazing and traffic tolerance, and even yield. It has been very successful in adding economic value to the forage and livestock operations of many producers (Bouton 2007). These traditionally developed varieties will also be used as the germplasm platform …


Is There A Benefit To Alfalfa Balage?, Gary Bates Feb 2010

Is There A Benefit To Alfalfa Balage?, Gary Bates

Kentucky Alfalfa and Stored Forage Conference

Making hay in the mid-South has always been a difficult process. High humidity and rainfall often make drying a long, tedious, if not impossible proposition. Over the last few years there has been an increased interest in making round bale silage, or balage, from forage crops. Fermenting alfalfa for storage has several advantages and disadvantages over regular haymaking systems.


Crop Updates 2010 - Genetically Modified Crops, Nutrition And Soils, James Fisher, Désirée Futures, Peter Tozer, Mike Jackson, John Moore, Jamees Neilsen, Geoff Anderson, Wen Chen, Richard Bell, Paul Blackwell, Allan Herbert, Stephen Davies, Ross Brennan, Mike Bolland, James Easton, Ryan Guthrie, Rowan Madderm, Robert Belford, Wal Anderson, Ian Edwards, Reg Lunt, Bill Bowden, Nigel Metz, Peter Newman, Breanne Best, Chris Gazey, Joel Andrew Feb 2010

Crop Updates 2010 - Genetically Modified Crops, Nutrition And Soils, James Fisher, Désirée Futures, Peter Tozer, Mike Jackson, John Moore, Jamees Neilsen, Geoff Anderson, Wen Chen, Richard Bell, Paul Blackwell, Allan Herbert, Stephen Davies, Ross Brennan, Mike Bolland, James Easton, Ryan Guthrie, Rowan Madderm, Robert Belford, Wal Anderson, Ian Edwards, Reg Lunt, Bill Bowden, Nigel Metz, Peter Newman, Breanne Best, Chris Gazey, Joel Andrew

Crop Updates

GENETICALLY MODIFIED CROPS

1. Evaluation of the environmental and economic impact of Roundup Ready® canola in the Western Australian crop production system, James Fisher and Désirée Futures, York, Western Australia, Peter Tozer, PRT Consulting, Armidale NSW

2. Controlling wild radish (Raphanus raphanistrum) in Roundup Ready®1 Canola: Outcomes from the Nufarm 2009 Roundup Ready small plot trial Program, Mike Jackson, Nufarm Australia Limited

3. Weed strategies for glyphosate tolerant crops, John Moore, Department of Agriculture and Food

4. Results of the 2009 Western Australia Roundup Ready® canola trials, Dr James Neilsen, Canola Systems …


Bite Marks Of The Giant Crocodylian Deinosuchus On Late Cretaceous (Campanian) Bones, David R. Schwimmer Jan 2010

Bite Marks Of The Giant Crocodylian Deinosuchus On Late Cretaceous (Campanian) Bones, David R. Schwimmer

Faculty Bibliography

The giant (~10 m) Late Cretaceous eusuchian crocodylians of the genus Deinosuchus are shown to have left large, blunt, sometimes penetrating bite marks on a significant number of sea turtle shells, and on several dinosaur specimens. The morphology of crocodylian bite marks is generally well documented, and the identification of bite traces specifically attributable to Deinosuchus may be made by reference to their size, age, habitat and prey selection. Deinosuchus species, and bite traces referable to the genus, are present on both sides of the Late Cretaceous Interior Seaway, and known only from Campanian deposits in the USA and northern …


What Are The Causes, Consequences And Correctives Of Fish Contamination In The Detroit River Aoc That Cause Health Consumption Advisories? (Final Report, Michigan Sea Grant Michu-T-10-001), Donna R. Kashian, Ken G. Drouillard, D. Haffner, Ann E. Krause, Z Liu, Larissa Sano Jan 2010

What Are The Causes, Consequences And Correctives Of Fish Contamination In The Detroit River Aoc That Cause Health Consumption Advisories? (Final Report, Michigan Sea Grant Michu-T-10-001), Donna R. Kashian, Ken G. Drouillard, D. Haffner, Ann E. Krause, Z Liu, Larissa Sano

Environmental Science and Geology Faculty Research Publications

Using an Integrated Assessment (IA) framework, we consolidated and utilized existing data from the Detroit River to develop models that both identify possible drivers of elevated fish contaminant body burdens, and to facilitate a more risk-based approach of tissue trigger-levels for consumption advisories. This integrated assessment approach was particularly useful for consumption advisories as it provided the ability to integrate and organize complex data in a manner that can help inform management decisions. In addition, the IA framework explicitly fosters collaboration and participation of multiple interested groups. We have capitalized on this component of IAs, by seeking the active participation …


Variations In Synechococcus Cell Quotas Of Phosphorus, Sulfur, Manganese, Iron, Nickel, And Zinc Within Mesoscale Eddies In The Sargasso Sea, Benjamin S. Twining, Daliangelis Nunez-Milland, Stefan Vogt, Rodney S. Johnson, Peter N. Sedwick Jan 2010

Variations In Synechococcus Cell Quotas Of Phosphorus, Sulfur, Manganese, Iron, Nickel, And Zinc Within Mesoscale Eddies In The Sargasso Sea, Benjamin S. Twining, Daliangelis Nunez-Milland, Stefan Vogt, Rodney S. Johnson, Peter N. Sedwick

OES Faculty Publications

The quotas of P, S, Mn, Fe, Ni, and Zn in individual Synechococcus cells collected from the surface and deep chlorophyll maximum (DCM) layer of three mesoscale eddies in the Sargasso Sea were measured using synchrotron X-ray fluorescence microscopy. Cells in a mode-water eddy had significantly higher P (57 +/- 10 amol) and Mn (28 +/- 7 zmol) cell quotas than cells collected from a cyclone (22 +/- 2 amol and 10 +/- 1 zmol, respectively) or anticyclone (25 +/- 3 amol and 18 +/- 3 zmol, respectively). Conversely, Ni and Zn quotas were significantly higher in the cells from …


A Functional And Ontogenetic Skull Analysis Of The Extant Rhinoceroses And Teleoceras Major, An Extinct Miocene North American Rhinoceros, Mark Daniel Hagge Jan 2010

A Functional And Ontogenetic Skull Analysis Of The Extant Rhinoceroses And Teleoceras Major, An Extinct Miocene North American Rhinoceros, Mark Daniel Hagge

LSU Master's Theses

Functional and ontogenetic skull differences among extant rhinoceroses and the extinct North American rhinoceros Teleoceras major were investigated to assess the unknown feeding ecology of Teleoceras. Ontogenetic skull sequences of the extant Indian rhino (Rhinoceros unicornis), Sumatran rhino (Dicerorhinus sumatrensis), white rhino (Ceratotherium simum), and black rhino (Diceros bicornis), and the extinct Miocene North American rhino T. major were gathered for both qualitative and quantitative assessments. Eleven functional characters related to specific feeding ecologies in extant perissodactyls were morphologically described, and each species’ skull development was described in detail. Nineteen linear skull measurements were taken across all specimens of all …


The Influences Of Microbial Diversity On Carbonate Geochemistry Across A Transition From Fresh To Saline Water In The Edwards Aquifer, Texas, Cassie Jo Gray Jan 2010

The Influences Of Microbial Diversity On Carbonate Geochemistry Across A Transition From Fresh To Saline Water In The Edwards Aquifer, Texas, Cassie Jo Gray

LSU Master's Theses

Microbially-mediated karstification through the production of metabolic byproducts has been well-documented in cave environments, but less is known about deep karstic settings. This research aimed to distinguish between microbial and geochemical influences on carbonate dissolution in the Edwards Aquifer, a prolific karst aquifer in central Texas, specifically from a transect of six wells across a transition from fresh to saline water in New Braunfels. For the first time, a portion of the aquifer’s bacterial diversity was examined from molecular 16S rRNA gene sequence analyses, which revealed that Alphaproteobacteria, Gammaproteobacteria, and Betaproteobacteria dominated the aquifer, with rare Bacteroidetes, Nitrospirae, and Firmicutes …