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Full-Text Articles in Physical Sciences and Mathematics
Manganese Bioavailability Drives Organic Matter Transformations Across Oxic-Anoxic Interfaces Via Biotic And Abiotic Pathways, Nathan A. Chin
Manganese Bioavailability Drives Organic Matter Transformations Across Oxic-Anoxic Interfaces Via Biotic And Abiotic Pathways, Nathan A. Chin
Masters Theses
Soil organic matter decomposition is a critical process that affects nutrient cycling, CO2 emissions, and carbon storage in terrestrial environments. Recent evidence suggests reactive manganese (Mn) phases, potent oxidants that depolymerize compounds like lignocellulose in soil organic matter, act as critical drivers of organic matter decomposition in soil and sediment environments. Furthermore, oxic-anoxic interfaces (OAIs) have been shown to be crucial hotspots for the formation of reactive Mn(III) species and associated organic matter degradation. However, the extent to which microbially mediated Mn(III) formation and subsequently Mn(III)-driven organic matter oxidation depends on Mn availability remains largely unknown. Additionally, the relative …
Hydrologic Controls On Phosphorus Speciation And Mobilization In A Subalpine Watershed (East River, Colorado), Lucia Isobel Arthen-Long
Hydrologic Controls On Phosphorus Speciation And Mobilization In A Subalpine Watershed (East River, Colorado), Lucia Isobel Arthen-Long
Masters Theses
The cycling of phosphorus (P) through floodplain environments is critical to ecosystem productivity and has significant implications on both water quality and soil fertility. P export from soils in response to saturation has been well documented, but the relative vulnerability of specific P pools to mobilization remains poorly constrained, as do the mechanisms mediating its release. The prediction of P availability in and export from mountainous floodplain soils is of great importance as global climate change is projected to significantly alter precipitation regimes in alpine systems. This study combined a thorough characterization of P distribution across a hillslope to floodplain …
Mid-Pliocene To Early Pleistocene Sea Surface And Land Temperature History Of Nw Australia Based On Organic Geochemical Proxies From Site U1463, Rebecca Smith
Masters Theses
Ocean gateways facilitate water circulation between ocean basins, and therefore directly impact thermohaline circulation and global climate. In order to better predict the effects of future climate change, it is critical to constrain past changes in ocean gateway behavior, and corresponding changes in thermohaline circulation, particularly during analogue periods for modern climate change. The Indonesian Throughflow (ITF) is a primary ocean gateway and vital component of the global conveyor that transports water from the Pacific Ocean into the Indian Ocean, however due to a lack of long and continuous sedimentary records from locations under its influence, changes in ITF behavior …
Examining The Mid- Brunhes Event In The Terrestrial Arctic: An Organic Geochemical Record From Lake El’Gygytgyn, Russia, Mary Helen Habicht
Examining The Mid- Brunhes Event In The Terrestrial Arctic: An Organic Geochemical Record From Lake El’Gygytgyn, Russia, Mary Helen Habicht
Masters Theses
The characteristic glacial and interglacial cycles of the Pleistocene underwent a climatic transition at ~430 ka known as the Mid- Brunhes Event (MBE). Many studies, particularly from the Southern Hemisphere have noted that after this transition, the amplitude of the climatic cycles increased. Despite the indication of an MBE signal in many globally distributed paleoclimate records, the geographic extent of the climatic transition remains unknown and its presence in northern hemisphere and terrestrial records is debated. Lake El’gygytgyn is located in the far- east Russian Arctic and provides the longest, most continuous record of Arctic climate (3.6 Ma). This study …
Mineralized Microbialites As Archives Of Environmental Evolution Of A Hypersaline Lake Basin: Laguna Negra, Catamarca Province, Argentina, Joy Buongiorno
Mineralized Microbialites As Archives Of Environmental Evolution Of A Hypersaline Lake Basin: Laguna Negra, Catamarca Province, Argentina, Joy Buongiorno
Masters Theses
Environmental fluctuations related to climate, biological productivity, and evaporation can be recorded by sedimentary archives within lacustrine depositional systems. Sediments within terminal, closed-basin lakes are amongst the most sensitive paleoenvironmental indicators, and have great potential for permitting detailed reconstruction of environmental conditions via a variety of geochemical and isotopic proxies. Microbialites, however, have been largely overlooked as repositories of paleoenvironmental data. Here, we investigate mineralized microbialites within Laguna Negra, a high-altitude (4100 meters above sea level) hypersaline, closed-basin lake in the Argentinian Puna region and explore the potential recovery of environmental signals from these unique sedimentary archives. Mineralized microbialites within …