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Full-Text Articles in Physical Sciences and Mathematics
Watering The Desert: Azraq, Public Opinion, And Environmental Post-Materialism, Wesley A. Gerard
Watering The Desert: Azraq, Public Opinion, And Environmental Post-Materialism, Wesley A. Gerard
Venture: The University of Mississippi Undergraduate Research Journal
This article focuses on physical, socioeconomic, and political changes in the community of Azraq, Jordan. Azraq, a small town in northeastern Jordan, sits atop a large aquifer that has been heavily pumped by the government for several decades in response to an increasing nationwide demand for water. This has led to large-scale transformations in not only the physical landscape surrounding the aquifer, but also in the daily lives, economic statuses, and political opinions of the people living there. My research thus fits the case of Azraq into larger academic discourse on groundwater governance, resource access, and environmentalism. I use a …
The Effects Of Hypoxia And Freshwater Intrusion On The Eastern Oyster (Crassostrea Virginica), James Henry Gledhill
The Effects Of Hypoxia And Freshwater Intrusion On The Eastern Oyster (Crassostrea Virginica), James Henry Gledhill
Electronic Theses and Dissertations
Recent estimates revealed a significant decrease in oyster populations worldwide. This drastic decrease has detrimental effects on coastal and estuarine ecosystems. Two environmental stressors that are thought to be contributing to the oyster population decline are hypoxia and excess freshwater intrusion. In this study, effects of hypoxia and low salinity on oysters were investigated using a combination of laboratory and field-based methods. In the laboratory, oysters were exposed to 2, 4, or 8 days of hypoxia (< 2 mg/L dissolved oxygen) folloby 6 days of recovery in normoxic conditions. At the same time, caged oysters were exposed to a naturally occurring hypoxic event in the field. After 8 days, laboratory-exposed oysters shoevidence of immunosuppression indicated by significant downregulation of the immune-related gene thymosin-β4 (Tβ-4) and a significant decrease in total circulating hemocytes compared to controls. However, in field oysters exposed to a naturally occurring hypoxic event, no effect on total hemocyte counts and an upregulation of Tβ-4 was observed. In a second field study, to investigate how oysters respond to prolonged freshwater exposure, caged oysters were placed on 23 April 2019 at six reef sites in the Mississippi Sound along with in situ water quality sensors. One-hundred percent mortality of caged oysters occurred at four of the six sites. Of the 6 six sites, Henderson Point Reef and Kittiwake Reef shosome caged oyster survival. At Henderson Point, where higher mortality was observed compared to Kittiwake, a significant increase in lipid peroxidation was detected. Analysis of mRNA expression of surviving caged and native oysters revealed downregulation of genes involved in immune function, low oxygen response, and osmoregulation. These results show possible evidence of energetic depression which inhibits adequate adaptation to low salinity conditions. Energetic depression and increased oxidative damage could have contributed to higher oyster mortality. Dredge sampling of native oysters at the all Mississippi Sound field sites on 27 September 2019, following recovery to ~15 ppt salinity, still indicated 100% native oyster mortality due to the prior prolonged freshwater exposure. Continued monitoring of western Mississippi Sound oyster reefs is crucial to observe recovery of oyster populations.
Application And Refinement Of Molecular Ecology Techniques For Amphibian Conservation, Stephanie Marie Burgess
Application And Refinement Of Molecular Ecology Techniques For Amphibian Conservation, Stephanie Marie Burgess
Electronic Theses and Dissertations
Wildlife conservation has become increasingly difficult due to habitat loss habitat fragmentation and land use change. Thus conservationists have embraced advances in molecular ecology such as landscape genetics and microbial bioinformatics that employ genetic techniques to further understand the relationship between individuals and their environment. In landscape genetics model inferences can be used to identify features that facilitate or resist gene flow providing a framework for anticipating the impacts of land use changes on a species’ ability to disperse. However the factors that affect the transferability of landscape genetics inferences are poorly understood and little is known about the effect …