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Articles 1 - 5 of 5
Full-Text Articles in Life Sciences
Geomorphology Of Tidal Wetlands: Impacts Of Extreme And Annual Flood Events To Salt Marsh And Mangrove Systems, Frances R. Griswold
Geomorphology Of Tidal Wetlands: Impacts Of Extreme And Annual Flood Events To Salt Marsh And Mangrove Systems, Frances R. Griswold
Doctoral Dissertations
Tidal wetlands are vital for buffering coastal settings from the threats of accelerated sea level rise and storms. Understanding the factors that are most influential for the maintenance and recovery of tidal wetlands after extreme events compounded by future accelerated sea level rise is of the utmost importance, yet this knowledge is not well established. Two tidal wetland schemas investigated in this dissertation are mangrove systems in Vieques, Puerto Rico (including robust lagoonal-mangrove forest systems and fringing mangrove forests), and salt marshes in New England. While the climatic forcings, vegetation type, and locations are vastly different for these two tidal …
Perceptions Of Historical Climate Change And Park Policy: The Impact On The Fremont Cottonwood In Zion National Park, Kathleen Kavarra Corr
Perceptions Of Historical Climate Change And Park Policy: The Impact On The Fremont Cottonwood In Zion National Park, Kathleen Kavarra Corr
Doctoral Dissertations
Despite its “natural” appearance and the Organic Act 1916 mandate for preservation of the natural environment in National Parks, the Virgin River as it flows through Zion National Park’s Zion Canyon was transformed through massive flood control re-engineering projects in the 1930s. The armoring of the river has had significant impacts on riparian vegetation, particularly on the stands of native Fremont Cottonwood trees that once filled the narrow valley. What was the motivation for this massive flood control project carried out in an arid region with less than 15 inches of rain per year? This dissertation explores the motivations which …
Physiological Constraints, Mechanisms, And Mineral Transformations Of Iron Reduction In Hyperthermophilic Crenarchaea, Srishti Kashyap
Physiological Constraints, Mechanisms, And Mineral Transformations Of Iron Reduction In Hyperthermophilic Crenarchaea, Srishti Kashyap
Doctoral Dissertations
Dissimilatory iron reduction by hyperthermophilic archaea occurs in many geothermal environments and typically relies on microbe-mineral interactions that transform various iron oxide minerals. However, the kinds of iron oxides that can be used, growth rates, extent of iron reduction, and the mineral transformations that occur due to this metabolism are poorly understood. This dissertation improves our fundamental understanding of the physiological mechanisms and mineral transformations of hyperthermophilic iron reduction using two model crenarchaea, Pyrodictium delaneyi and Pyrobaculum islandicum. Using growth yields and metabolite production rates, we demonstrated that a broad range of Fe(III) (oxyhydr)oxides of variable thermodynamic stability was …
Assessing Kiln-Produced Hardwood Biochar For Improving Soil Health In A Temperate Climate Agricultural Soil, Emily J. Cole
Assessing Kiln-Produced Hardwood Biochar For Improving Soil Health In A Temperate Climate Agricultural Soil, Emily J. Cole
Doctoral Dissertations
Soil quality has become a major factor used in assessing sustainable land management and the overall environmental quality, food security, and economic viability of agricultural lands. Recently, biochar has been touted as having many potential uses as a soil amendment for improving soil quality, specifically improving cation exchange capacity, pH and nutrient availability. However, soil biology also plays a significant role in biogeochemical processes that influence soil health and should be included in a more comprehensive study of soil health. This dissertation describes 4 projects within the same 3-year field study with the cumulative purpose of better understanding the effect …
Microbe-Mineral Relationships And Biogenic Mineral Transformations In Actively Venting Deep-Sea Hydrothermal Sulfide Chimneys, Tzihsuan J. Lin
Microbe-Mineral Relationships And Biogenic Mineral Transformations In Actively Venting Deep-Sea Hydrothermal Sulfide Chimneys, Tzihsuan J. Lin
Doctoral Dissertations
This dissertation uses a combination of microbiology, mineralogy, and geochemistry to understand dissimilatory iron reduction in hyperthermophilic archaea and the role and potential impact of these and other vent microorganisms within active deep-sea hydrothermal vent chimneys. The central objective of the dissertation is to determine if mineral composition and chimney type are among the primary determinants of microbial community composition and hyperthermophilic, dissimilatory iron reducer growth, in addition to other environmental factors such as nutrient availability, temperature, pH, and chlorinity. This is done using samples and organisms collected from the Endeavour Segment of the Juan de Fuca Ridge in the …