My PhD research focused on understanding the biogeochemistry of organic sulfur formation using compound-specific stable isotope analysis. |
hopanoid thiophene - an organic sulfur compound
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The purpose of such research is to unravel some of the complexities of the sulfur cycle, paying particular attention to organic sulfur. Using new analytical capabilities to measure compound specific sulfur isotopes we will be able to elucidate the processes surrounding organic sulfur formation and what role environmental factors play in the cycling of sulfur in both aqueous and sedimentary environments. Ultimately, these measurements will establish a baseline of molecular organic sulfur isotopes which can then be used for understanding the coupled biogeochemical cycles of carbon and sulfur through geologic time, as well as the biogeochemistry of early Earth systems and origins of life.
This work was completed under the direction of Dr. Josef P. Werne at the University of Pittsburgh and is supported by funds from the National Science Foundation (NSF) and the American Chemical Society Petroleum Research Fund (ACS - PRF).
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Sulfurization of organic matterLaboratory sulfurization of carbohydrates, lipids, and DOM will establish constraints on the sulfur isotopic signature of compounds found in natural systems. Laboratory results will be applied to natural samples from the Upper Jurassic Kimmeridge Clay Formation, where the preservation of carbohydrates through sulfurization has resulted in the extremely high organic carbon content (34%) of the Blackstone Band, in particular.
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Modern analog for Earth's early ocean - sulfur cyclingAnalysis of water column and sediment samples from two euxinic lake systems (Fayetteville Green Lake, NY, USA and Mahoney Lake, BC, Canada) will establish a baseline for the sulfur isotope values of organic sulfur compounds in natural environments. We will be looking for general patterns of fractionation among different types of molecules and how they may relate to environmental conditions. Fayetteville Green Lake is considered a modern analog to the ocean ca. 3 billion years ago and provides a unique opportunity to examine how Earth’s early ocean operated with respect to sulfur cycling dynamics.
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Split surface of a sediment core from Mahoney Lake, British Colombia, Canada
