This thesis examines the energy return on investment (EROI) of a model 3 MW hybrid gas-geothermal plant on the Texas Gulf Coast. The model plant uses a design similar to the DOE Pleasant Bayou No. 2 test geothermal plant, and uses a gas engine to harness entrained methane and an Organic Rankine Cycle turbine to harness thermal energy from hot brines. The indirect energy cost was calculated using the Carnegie Mellon University Economic Input-Output Life Environmental Life Cycle Analysis (EIO-LCA) model. The EROI of the plant using the 1997 EIO-LCA energy data is 12.40, and the EROI of the plant using 2002 EIO-LCA energy data is 14.18. Sensitivity analysis was run to determine how the plant parameters affect the EROI. A literature review of the EROI of different power sources shows that the EROI of the hybrid geothermal plant is greater than the EROI of flash steam geothermal and solar, but is lower than the EROI of dry steam geothermal, wind power, nuclear, coal, gas, and hydroelectric plants. An analysis of the EROI to financial return on investment (FROI) shows that the FROI for a hybrid geothermal plant could be competitive with wind and solar as a viable renewable resource in the Texas electricity market. / text

To show how mass-production principles and welding in shipbuilding altered the economic conditions along the Gulf coast, this investigation relied on a chronological narrative to illustrate the importance of timing in addition to identifying the significant factors causing the changes. The account begins with a description of the Gulf coast shipyards during World War I and ends shortly after World War II. The necessary factors for Gulf coast participation in shipbuilding are developed in two chapters followed by an evaluation of the specific accomplishments of five Gulf coast shipyards during and after World War II. The effects of the changes in the shipyards on labor are also discussed.

The Woodland-period (ca. 1000 B.C. to A.D. 1050) fisher-hunter-gatherers of the Crystal River drainage on Florida’s Big Bend Coast are well known among southeastern archaeologists for their elaborate shell mound architecture, maritime lifeway, and exotic exchange goods. Recent archaeological investigations at the Crystal River site have employed high-resolution topographic mapping, geophysical surveys, trench excavations, and coring to model the temporality of mound construction and occupation at the site; this work has set the stage for subsequent research focusing on community structure, resource extraction, and human-ecosystem dynamics. However, like many central and north peninsular Gulf Coast sites, our understanding of Crystal River lacks robust environmental context. Various geologists and archaeologists have proposed that several major sea-level oscillations transpired during the late Holocene at scales that would have heavily impacted coastal habitation; however, the paleoenvironmental reconstructions available for the Gulf Coast disagree dramatically about the timing, extent, and general pattern of sea-level history, which discourages the use of non-localized (or averaged) reconstructions for archaeological interpretation. This study investigates palynological remains recovered from midden and wetland core samples taken at Crystal River site to provide a record of vegetation response to both externally driven environmental changes (i.e. sea-level and climate flux) and anthropogenic landscape alterations throughout the first millennium A.D. Results show that stratified midden deposits and wetland soils at Crystal River site contain intact fossil pollen assemblages that span the site’s occupational history and extend into pre- and post-abandonment periods. The pollen data suggest that local communities experienced substantial environmental changes that reorganized the composition and geographic distribution of coastal ecosystems. These transformations align well with broadly recognized climatic episodes (i.e. the Roman Warm Period, Vandal Minimum, and Medieval Warm Period). In contrast, the Crystal River drainage experienced a unique pattern of sea-level flux that does not approximate oft-cited sea-level records developed elsewhere on Florida’s Gulf Coast, or the averaged sea-level curves for the Gulf Coast. Additionally, the microbotanical remains preserved within midden soils at Crystal River site may speak to the roles of particular plants as subsistence, technological, medicinal, and/or ceremonial resources.

Hundreds of wetland bird species use ricelands annually in the Gulf Coast Prairie region of Louisiana and Texas. Much of the original ecosystem was transformed for rice and other crops, cattle ranching, flood control, and other human uses. Flooded production and idled ricelands provide critical foraging habitat for breeding, migrating, and wintering wetland birds. Ricelands in coastal Louisiana and Texas provide approximately 42% of the estimated habitat carrying capacity for wintering waterfowl in this region. In 2010, the Deepwater Horizon oil spill in the Gulf of Mexico prompted enactment of the Migratory Bird Habitat Initiative (MBHI) by USDA Natural Resources Conservation Service. The MBHI provided avian habitat, including flooded ricelands, inland from oil impacted areas. My objectives were to: 1) estimate and model variation in biomass of waste rice and natural seeds as potential waterfowl forage in Gulf Coast Prairie ricelands, 2) estimate and model variation in wetland bird use of ricelands, and 3) conduct sensitivity analyses of bioenergetics models by varying foraging thresholds and true metabolizable energy (TME) values. A growing season of ~270 days allows Gulf Coast rice producers to grow two rice crops (i.e., the second termed ratoon). Waste rice was greatest in production fields with harvested and standing ratoon crops, and natural seed biomass was greatest in idled fields with standing vegetation. Wetland bird species richness and waterbird abundance were greatest in shallowly flooded (1–15 cm) ricelands with sparse vertical vegetation (1–20 cm), and duck abundance was greatest in shallow–intermediately (1–30 cm) flooded ricelands with short vegetation (1–15 cm). Shallowly flooded rice fields containing harvested or standing ratoon crops, and shallowly flooded idled fields with standing vegetation provided abundant potential foods for waterfowl and waterbirds. Bioenergetics models indicated that planners in the Gulf Coast Prairie region may be underestimating riceland habitat requirements for waterfowl by 10,000 ha. Models were most sensitive to changes in seed biomass estimates, and less sensitive to changes in foraging thresholds and TME values. Collectively, these results will facilitate conservation partners to refine models for conserving habitats for waterfowl and other waterbirds in the Gulf Coast Prairie.

This study aims to conduct an assessment of the land cover change of the Mississippi and Alabama coastal region, an integral part of the Gulf Coast ecological makeup. Landsat satellite data were used to perform a supervised classification using the imagery captured by Landsat sensors including Landsat 1-2 Multispectral Scanner (MSS), Landsat 4-5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper (ETM+), and Landsat 8 Operational Land Imager (OLI) from 1973 to 2015. The objective of this study is to build a long-term assessment of urban development and land cover change over the past four decades for the Alabama and Mississippi Gulf Coast and to characterize these changes using Landscape Metrics (LM). The findings of this study indicate that the urban land cover doubled in size between 1973 and 2015. This expansion was accompanied by a high degree of urban fragmentation during the first half of the study period and then a gradual leveling off. Local, state, and federal authorities can use the results of this study to build mitigation plans, coastal development planning, and serve as the primary evaluation of the current urban development for city planners, environmental advocates, and community leaders to reduce degradation for this environmentally sensitive coastal region.

High levels of Enterococcus are the most frequent reason for beach closures on the Mississippi Gulf Coast and can be made worse by human activities. When beaches close, tourism can decrease, affecting sales. This study aims to 1) analyze the regional economic impact of beach closures at the county level, 2) show empirically how serious the impact of high levels of Enterococcus are compared to other causes of beach closures, and 3) discuss the policy implications for regional economies linked to beach closures. I use a response function approach with beach closure and county-level monthly gross taxable sales data. Results indicate that Enterococcus-related beach closures have significantly negative effects on sales, particularly in the Accommodations and Food Services sector. The effects of bacteria-related beach closures are not much different than effects of other causes of beach closures. The results support policy recommendations for reduced beach grooming and improved sewer infrastructure.

The numerous benefits that wetlands provide make them essential to ecosystem services and ecological functions. Historically, wetland losses have been caused by natural and anthropogenic changes. In Texas, nearly 50% of coastal wetland habitat has been lost since the 1930s and losses in the Lower Neches watershed have been some of the most extensive. Restoration is a way to mitigate these losses and can be accomplished in many ways. Each restoration design creates different aquatic habitats that can influence both submerged aquatic vegetation (SAV) and faunal communities. The restoration of the Lower Neches Wildlife Management Area (LNWMA) has created the conditions for the growth of the invasive submerged macrophyte, Myriophyllum spicatum (Eurasian watermilfoil) which may be competing with the native aquatic grass, Ruppia maritima (widgeongrass) for essential nutrients. In this study, an attempt was made to link restoration design with both SAV and aquatic fauna community structures by using a throw trap to characterize assemblages observed in three different types of restored marshes. We also performed two controlled mesocosm experiments in 0.5 gal aquariums to determine growth inhibition by M. spicatum on R. maritima. Analyses using Kruskal-Wallis non-parametric test determined that temporal variations in fauna and SAV community composition was greater than any restoration effect. Discriminant Function Analyses (DFAs) determined two to three key faunal species that best predicted association among restoration designs, but linear regressions could not determine any consistent relationship between individual species density and biomass of the dominant SAV species, M. spicatum. For the mesocosm experiments, M. spicatum inhibited the biomass production and branch count of R. maritima when the two species are grown together (ANOVA, p = 0.004 and 0.003, respectively). Changes in SAV assemblages due to competition and habitat characteristics could play a major role in determining faunal community. In order to minimize the temporal effect observed and better determine any habitat pattern that may be present, a much longer study is necessary.

Bentonite clays are exposed in Paleogene strata stretching over 650 km parallel to the Texas coastline. This study focuses on a white and blue and a yellow and brown commercial Ca-montmorillonite bentonite near the city of Gonzales, Gonzales county, Texas. The deposits have stratigraphic ages of Late Eocene (~36.7 - 32.7 Ma). The bentonites in these deposits have varying colors, purities and brightness affording them diverse industrial uses. The distribution and geologic character of the high purity white and blue bentonite suggests that the deposit represents an accumulation of volcanic ash in a secondary tidal channel during the ash-fall event. A low rate of terrigenous clastic sedimentation and rapid accumulation of fresh ash were critical to the formation of high purity clay. The lower purity yellow and brown bentonites appear to have a fluvial origin marked by higher rates of detrital sedimentation and episodic accumulation of clay and ash. The bentonite and associated strata were studied using optical microscopy, SEM, XRD and REE analyses to constrain their textural, mineralogic, and chemical character. vii Eocene pyroclastic volcanism is well documented from sources in southwestern North America, specifically in the Sierra Madre Occidental (Mexico), Trans-Pecos (Texas) and Mogollan-Datil (New Mexico) volcanic fields. Projected Eocene wind patterns support this region as a potential source for the Gonzales bentonites. A comparison of the trace and REE fingerprints of the white and blue bentonites and the yellow and brown bentonites with data available for Late Eocene volcanics in the North American Volcanic Database provides a couple of potential matches. The strongest potential match for the Late Eocene bentonite protolith is described as a sample of silicic tuff with an age range of 32.2 – 30.6 Ma, located in the southern Mexican state of Oaxaca. While the trace and REE match is strong, the tuff is somewhat young compared to the Jackson Group sediments. In addition, the sample location is due almost directly south of the Gonzales deposits, rather than the western location expected for a Gonzales bentonite source. The other potential matches are located in New Mexico, and the Mexican state of Chihuahua. These potential matches only have 6 REE available for comparison, and require further investigation. Many Paleogene volcanic units in southern North America are undocumented with regard to REE data or precise absolute ages. As additional geochemical analyses become available for a more extensive suite of Paleogene volcanic units, stronger matches with Gulf of Mexico Basin bentonites are expected to emerge. / text

The decades after World War II were a time of growth and change for queer people across the country. Many chose to move to major metropolitan centers in order to pursue a life of openness and be part of queer communities. However, those people only account for part of the story of queer history. Other queer people chose to stay in small towns and create their own queer spaces for socializing and community building. The Gulf Coast of Florida is a place where queer people chose to create queer community where they lived through such actions as private house parties and opening bars. The unique place of the Gulf Coast as a tourist destination allowed queer people to build and join communication networks that furthered the growth of a sense of community leading ultimately to the founding of Bay AIDS Services and Information Coalition in 1989.

Although sea-breezes frequently initiate convection, it is oftentimes challenging to forecast the precise location of storm development. This research examines temporal and spatial characteristics of sea-breeze driven convection and environmental conditions that support convective or non-convective sea-breeze days along the Northern Gulf Coast. Base reflectivity products were used to identify the initial time of convection (values greater than 30 dBZs) along the sea-breeze front. It was found that convective sea-breezes initiated earlier in the day compared to non-convective sea-breezes. Mapping convective cells in ArcGIS revealed favored locations of thunderstorm development including the southeastern cusp of Mobile County, Alabama and convex coastlines. Meteorological variables from the North American Regional Reanalysis dataset were compared between convective and non-convective sea-breeze days via a bootstrap analysis to reveal environmental characteristics pertinent to forecasting sea-breeze driven convection. Lapse rates, CAPE, CIN, specific humidity, dew point temperature, relative humidity, and precipitable water values were statistically significant.