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Full-Text Articles in Physical Sciences and Mathematics

Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp Jan 2019

Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp

Dissertations, Master's Theses and Master's Reports

Boreal peatlands store approximately one third of the earth’s terrestrial carbon, locked away in currently waterlogged and frozen conditions. Peatlands of boreal and arctic ecosystems are affected increasingly by shifting hydrology caused by climate change. The consequences of these relatively rapid ecosystem changes on carbon cycling between the landscape and the atmosphere could provide an amplifying feedback to climate warming. Alternatively, the advancement of terrestrial vegetation into once waterlogged soils could uptake carbon as a sink. Previous work suggests that fens will become an increasingly dominant landscape feature in the boreal. However, studies investigating fens, their response to hydrologic and …


Monitoring And Mitigation Of Elevated Co2 Impacts Using Microalgae, Terry-Rene Wiesner Brown Jul 2016

Monitoring And Mitigation Of Elevated Co2 Impacts Using Microalgae, Terry-Rene Wiesner Brown

USF Tampa Graduate Theses and Dissertations

Climate change is arguably the greatest environmental and economic challenge of our time. There are considerable documented and projected impacts to both human and natural systems as a result of climate change. These impacts include changes in temperature, sea level, precipitation patterns, and biogeography of ecologically and economically relevant species, including pathogens. One of the main drivers of climate change is elevated levels of atmospheric carbon dioxide (CO2), a greenhouse gas. Since pre-industrial times, atmospheric CO2 levels have increased from approximately 280 ppm to over 400 ppm, as a result of fossil fuel combustion, cement production and …


Effects Of Epichloë Coenophiala−Tall Fescue Symbiosis On Plant-Microbe-Soil Interactions In A Temperate Pasture, Lindsey C. Slaughter Jan 2016

Effects Of Epichloë Coenophiala−Tall Fescue Symbiosis On Plant-Microbe-Soil Interactions In A Temperate Pasture, Lindsey C. Slaughter

Theses and Dissertations--Plant and Soil Sciences

Plants interact in myriad ways with microorganisms to influence ecosystem processes such as nutrient cycling, which can regulate ecosystem response to global change. One important plant-microbe symbiosis occurs between cool-season grasses and asexual fungal Epichloë endophytes, such as tall fescue (Schedonorus arundinaceus) and Epichloë coenophiala. Because the common toxic strain of the endophyte (CTE) harms grazing livestock, non-livestock toxic endophyte (NTE) strains have been developed and are increasingly deployed in pastures. Little is known about how these symbioses impact other plant-microbe interactions and microbe-mediated soil processes in grassland ecosystems. I conducted three studies to determine how E. …


Pathogen Removal In Natural Wastewater Treatment And Resource Recovery Systems: Solutions For Small Cities In An Urbanizing World, Matthew Eric Verbyla Nov 2015

Pathogen Removal In Natural Wastewater Treatment And Resource Recovery Systems: Solutions For Small Cities In An Urbanizing World, Matthew Eric Verbyla

USF Tampa Graduate Theses and Dissertations

Sanitation, renewable energy, and food security are among the most pressing global development needs of the century, especially for small cities with rapid population growth. Currently, 53% of the world’s population either lacks access to improved sanitation or discharges fecal waste to the environment without treatment. Furthermore, 80% of food consumed in developing regions is produced by 500 million small farms, and while many of them are still rain-fed, irrigated agriculture is increasing. The post-2015 Sustainable Development Goals, recently adopted by the United Nations, include targets to address the water-energy-food nexus. Wastewater reuse in agriculture can be an important solution …


Correlation Analysis Of Climatic Variables, Migration And Dengue Cases In Southeast Florida, Brunilda Lugo Jan 2015

Correlation Analysis Of Climatic Variables, Migration And Dengue Cases In Southeast Florida, Brunilda Lugo

Walden Dissertations and Doctoral Studies

Dengue fever is a debilitating, viral, mosquito-borne disease occurring in tropical and subtropical areas in the world. The majority of dengue cases in the United States were acquired in endemic areas by travelers or immigrants. However, in recent years, autochthonous (locally acquired) dengue cases have been diagnosed in Florida. The purpose of this study was to find an association between potential risk factors and the expansion of dengue fever in the United States. Guided by the eco-bio-social framework, which offers a broad assessment of risk factors for the illness, a retrospective design was used with archival data to correlate changes …