Physical Sciences and Mathematics Commons^™

Eastern Tropical Pacific Climate And El Niño Variability During The Past Millennium, Gerald Thomas Rustic

Dissertations, Theses, and Capstone Projects

The El Niño Southern Oscillation (ENSO) has been implicated in large-scale climate shifts of the past millennia, but paleoclimate records from the dynamically vital eastern equatorial Pacific Ocean (EEP) spanning the past millennium are sparse. This has limited our understanding of tropical Pacific dynamics, leaving questions regarding the source of ENSO variability unanswered. Here I seek to address some of these questions regarding relationship between ENSO and tropical Pacific mean state, and the relationship between the tropical Pacific and large-scale climate. Mean EEP sea surface temperature (SST) for the past millennium was reconstructed using Mg/Ca ratios in Globigerinoides ruber from …

Microfossils As Proxies For Holocene Climate In Semi-Enclosed Basins: The Hudson River Estuary, New York, Usa And The Marmara Sea, Turkey, Damayanti Gurung

Dissertations, Theses, and Capstone Projects

The transition from the late Pleistocene glacial to the warmer Holocene interglacial occurred within a series of climatic oscillations. The Holocene, a relatively warm and stable period, was also marked by smaller climatic variability of millennial- to-centennial-scale oscillations. Furthermore, during this period global sea level was much lower than at present. My present study will analyze micro-fossils as proxies for their response to these climatic fluctuations, as well as marine influences during the late Pleistocene to Holocene periods. Sediments from marginal basin environments have been selected for the study due to their connection to the open sea and terrestrial environments, …

The State Of The Oligocene Icehouse World: Sedimentology, Provenance, And Stable Isotopes Of Marine Sediments From The Antarctic Continental Margin, Daniel William Hauptvogel

Dissertations, Theses, and Capstone Projects

The Oligocene Epoch (34-23 Ma) was a dynamic time in Antarctica, with previous ice volume estimates suggesting fluctuations from below 50 % up to 140 % of modern all while atmospheric CO₂ decreased from above 1,000 ppm in the Early Oligocene to near modern levels by the Late Oligocene. Most of what is known about the Oligocene Antarctic cryosphere however, is derived from distal sedimentary records that can only provide a generalized view of the cryospheric dynamics in Antarctica. To better understand regional differences in Antarctic glacial dynamics, proximal records are needed. This dissertation advances our understanding of these …

Carbon And Nitrogen Dynamics From Slow Pools Of Soil Organic Matter In A Temperate Forest: Pyrogenic Organic Matter And And Root Litter, Fernanda Dos Santos

Dissertations, Theses, and Capstone Projects

Soil organic matter (SOM) is the dominant reservoir of organic carbon (OC) in terrestrial ecosystems, storing approximately three times the size of the C pool in the atmosphere. In temperate forests, a major fraction of the SOM consists of slowly decaying soil organic C (SOC) pools. While slowly cycling C pools constitute a large reservoir of stable C in soils, the dominant environmental factors controlling this C pool remain unresolved. This research investigates two significant, but poorly characterized slowly decaying C pools: fine root litter (< 2mm) and thermally altered plant biomass (pyrogenic organic matter, PyOM). Specifically, I used compound-specific stable isotope analysis (¹³C and ¹⁵N) as my main methodological approach to examine the (1) …

Paleoecology Of Late Cretaceous Methane Cold-Seeps Of The Pierre Shale, South Dakota, Kimberly Cynthia Handle

Dissertations, Theses, and Capstone Projects

Most investigations of ancient methane seeps focus on either the geologic or paleontological aspects of these extreme environments. In contrast, this thesis encompasses both disciplines to evaluate the paleoecology of these systems with greater detail than previously published either within the Western Interior Basin or elsewhere. This thesis addresses the following questions: 1) Are the changes in mineralogy of a seep discernable and predictable as a seep shifts from a clay-based environment to a carbonate-based environment? 2) What are the foundation organism(s) of Late Cretaceous methane cold-seeps? 3) Is there a correlation to the mineralogic changes and shifts in community …

The Interaction Between Arsenic And Struvite During Coprecipitation And Adsorption Processes, Ning Ma

Dissertations, Theses, and Capstone Projects

The formation of struvite, MgNH4PO4*6H2O (MAP), from wastes is one of the methods that can be used to recover P from wastes efficiently. However, since there are usually toxic components in the wastes, like arsenic (As), the possibility of having toxic contaminants in MAP is a big concern. So, the interaction between As and MAP during coprecipitation (CPT) and adsorption (ADS) processes were studied at pH 8-11. MAP precipitated without As at pH 8-11 was also characterized.

During CPT process, the MAP was precipitated from a MgCl2-(NH4)2HPO4-NaCl-H2O system spiked with As at an initial pH (pHi) of 8-11. The batch …

Biodegradation Of Fuel Oxygenates In Northeastern United States Aquifers With An Analysis Of Underground Storage Tank Leaks, Gordon Hinshalwood

Dissertations, Theses, and Capstone Projects

During the past decade the application of monitored natural attenuation has become one of the predominant technologies used in the remediation of gasoline spills impacting subsurface soils and groundwater. The success of this method has depended, for the most part, on the biodegradation of those gasoline constituents that dissolve into groundwater and transport with the groundwater most readily.

One of the most mobile components of gasoline formulations during the past 20 years has been methyl tertiary butyl ether (MTBE), which has traditionally been viewed in both the scientific and the regulatory communities as relatively recalcitrant to biodegradation. However, cases of …