Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 24 for “"Geobiology"”.
-
Geobiology of marine magnetotactic bacteria
Magnetotactic bacteria (MTB) biomineralize intracellular membrane-bound crystals of magnetite (Fe3O4) or greigite (Fe3S4), and are abundant in the suboxic to anoxic zones of stratified marine environments worldwide. Their population densities (up to 105 cells ml−1) and high intracellular iron …
-
Geobiology of marine magnetotactic bacteria
Magnetotactic bacteria (MTB) biomineralize intracellular membrane-bound crystals of magnetite (Fe3O4) or greigite (Fe3S4), and are abundant in the suboxic to anoxic zones of stratified marine environments worldwide. Their population densities (up to 105 cells ml-1) and high intracellular iron …
-
Contributions to the Neoproterozoic Geobiology
This thesis makes several contributions to improve our understanding of the Neoproterozoic Paleobiology. In chapter 1, a comprehensive quantitative analysis of the Ediacara fossils indicates that the oldest Ediacara assemblage "the Avalon assemblage" already encompassed the full range of Ediacara …
-
The Geobiology of the Paleoproterozoic Belcher Group, Nunavut, Canada
The Belcher Group Microbiota (BGM) are a collection of microbial organisms from the Paleoproterozoic (~2.0 to 1.8 Ga) Belcher Group from the Belcher Islands, Nunavut, Canada. The Belcher Group is exceptionally well-preserved, having avoided deep burial or strong deformation during the Trans-Hudson …
-
Contributions to late Ediacaran geobiology in South China and southern Namibia
The Ediacaran, particularly the late Ediacaran-Cambrian (E-") boundary (551-541 Ma), has been noted as a major time of biological and biochemical transition, including: the rise of predators, the emergence of skeletons, the radiation of bioturbators, and large fluctuations in oceanic chemical …
-
Testing the ancient marine redox record from oxygenic photosynthesis to photic zone euxina
… redox history is one of the great challenges of geobiology and geochemistry. The accumulation of photosynthetically derived oxygen transformed the redox state of Earth’s surface environments, setting the stage for the subsequent evolution of complex life. However, the timing of the advent of …
-
Testing the ancient marine redox record from oxygenic photosynthesis to photic zone euxina
… redox history is one of the great challenges of geobiology and geochemistry. The accumulation of photosynthetically derived oxygen transformed the redox state of Earth's surface environments, setting the stage for the subsequent evolution of complex life. However, the timing of the advent of …
-
Lateral Transfer of DNA in Protocell-like Synthetic Cells
… cells is a central problem in Astrobiology and Geobiology. This thesis investigates whether electroporation can mediate the transfer of DNA into and between synthetic cells, potentially enabling gene expression in initially DNA-free compartments. Both TXTL and PURE-based cell-free expression …
-
Neutrino capital of the world
… ranging from astrophysics to deep subsurface geobiology. In the process, the state of South Dakota has introduced a unique funding scheme in which science is democratic. Politicians, scientists and regular folks play important roles in the neutrino populist movement, working together to …
-
Site-based data curation: bridging data collection protocols and curatorial processes at scientifically significant sites
… curation at scientifically significant sites: geobiology at Yellowstone National Park and paleontology at the La Brea Tar Pits. The case studies investigate: What information do different stakeholders value about the natural sites at which they work? How do these values manifest in data …
-
Radiative Transfer in the Martian Environment: In-Situ Results from the MSL Curiosity Rover and Laboratory Experimentation on Martian Regolith and Crystalline Rock Analogs
Global circulation models predicted a suppressed planetary boundary layer within Gale Crater prior to the landing of the Mars Science Laboratory. Images from Mars allow the amount of suspended dust near the crater floor to be estimated numerically. The atmosphere within the crater is shown to be …
-
Effects of the 1982-1983 El Niño mega event on bivalve mollusk biomineralization
Marine bivalve mollusks are valued as climate change recorders due to predictable growth rates and the recording of the ambient seawater environment into their shells (e.g., temperature, dissolved inorganic carbon (DIC)). Bivalves that endure extreme environmental perturbations also exhibit …
-
Sulfur, carbon, and oxygen isotopes of coexisting sulfides and carbonates in gas and oil seeps from the Gulf of Mexico
Microbial processes consisting of bacterial sulfate reduction (BSR), bacterial disproportionation of sulfur (BDS), and BSR coupled with anaerobic oxidation of methane (BSR-AOM) occur in the Gulf of Mexico (GOM) at sites where hydrocarbon oil and gas seep through conduits to the seafloor. Thus far, …
-
Paleoecology and Taphonomy of Ediacaran macrofossils from the Khatyspyt Formation, Olenek Uplift, Siberia
The Ediacaran Period (635 – 541 Ma) is a critical transition in the history of the Earth and life. It is marked by the appearance of enigmatic Ediacara-like fossils and macroalgae, which had existed since the early Proterozoic, but started to diversify morphologically and ecologically during this …
-
Contributions to Exceptional Fossil Preservation
Exceptionally preserved fossils—or fossils preserved with remains of originally non-biomineralized (i.e. soft) tissues—constitute a key resource for investigating the history of the biosphere. In comparison to fossils of biomineralized skeletal elements, which represent the majority of the fossil …
-
Hitching a ride: A gastropod-associated microbiome community at a Hydrate Ride methane seep and impacts on local biogeochemical cycling
Exploration of cold seeps from geological, chemical, and biological perspectives has grown exponentially in recent decades since the first discovery of cold seeps in the 1980s. Symbiotic relationships, often rooted in geochemistry of the environment, have proven to be ubiquitous at cold seeps. …
-
Physical, chemical and biological controls on the origin, crystallization and dissolution of human kidney stones
Kidney stones are mineral deposits in the renal system that afflict 1 in 11 people worldwide and the incidence and prevalence is increasing globally. Over 70% of stones are composed of calcium oxalate and other mineralogies include struvite, brushite, and apatite. Currently, stones are thought to …
-
Assessing the Role of Solution Chemistry and Organic Matter in the Genesis of the Dengying Formation Dolostones at Sichuan Basin, China
The role that microorganisms play in low-temperature dolomite formation is still unresolved. Given the scarcity of dolomite in modern low-temperature depositional settings, controls on its formation remain unclear. Textural evidence from modern and ancient geomicrobiological dolomite-forming …
-
Microbial Diversity and Geochemical Energy Sources of Tutum Bay, Ambitle Island, Papua New Guinea, an Arsenic-Rich, Shallow-Sea Hydrothermal System
I investigate the hydrothermal system located in Tutum Bay, Ambitle Island, Papua New Guinea, a shallow-sea system ~5 - 10 meters below sea level that is arsenic-rich. Hydrothermal vents in the bay expel fluids with arsenite: AsIII) concentrations as high as 950 μg/L. To determine the role that …
-
Carbon cycling: The role of Methane and Copper in an early ocean analogue Lake Matano
This dissertation examines the carbon cycle of a modern ferruginous environment (Lake Matano, Indonesia), with a primary focus on the critical role of methane in carbon redistribution in this system. In addition, the mobility and availability of copper (Cu) (an essential component of microbial …
Page 1 of 2