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Molecular Biogeochemistry of modern and ancient marine microbes
(Massachusetts Institute of Technology, 2010)
Biological activity has shaped the surface of the earth in numerous ways, but life's most pervasive and persistent global impact has been the secular oxidation of the surface environment. Through primary production - the ...
Insights into vitamin B₁₂ production, acquisition, and use by marine microbes
(Massachusetts Institute of Technology, 2012)
The distribution and magnitude of marine primary production helps determine the ocean's role in global carbon cycling. Constraining factors that impact this productivity and elucidating selective pressures that drive the ...
Evolution of Anthropogenic Pb and Pb isotopes in the deep North Atlantic Ocean and the Indian Ocean
(Massachusetts Institute of Technology, 2013)
Pb and Pb isotopes in the ocean have varied on decadal to centennial time scales due to anthropogenic Pb inputs. Thus, tracing the temporal variation of Pb and Pb isotopes in the ocean provides information on the major ...
Physical influences on phytoplankton ecology : models and observations
(Massachusetts Institute of Technology, 2013)
The physical environment in the oceans dictates not only how phytoplankton cells are dispersed and their populations intermingled, but also mediates the supply of nutrients to the surface mixed layer. In this thesis I ...
Laboratory and field-based investigations of subsurface geochemical processes in seafloor hydrothermal systems
(Massachusetts Institute of Technology, 2010)
This thesis presents the results of four discrete investigations into processes governing the organic and inorganic chemical composition of seafloor hydrothermal fluids in a variety of geologic settings. Though Chapters 2 ...
Boundary layer dynamics and deep ocean mixing in Mid-Atlantic Ridge canyons
(Massachusetts Institute of Technology, 2013)
Physical oceanographers have known for several decades the total amount of abyssal mixing and upwelling required to balance the deep-water formation, but are still working to understand the mechanisms and locations-how and ...
Determining timescales of natural carbonation of peridotite in the Samail Ophiolite, Sultanate of Oman
(Massachusetts Institute of Technology, 2012)
Determining timescales of the formation and preservation of carbonate alteration products in mantle peridotite is important in order to better understand the role of this potentially important sink in the global carbon ...
Hydrological and biogeochemical cycling along the Greenland ice sheet margin
(Massachusetts Institute of Technology, 2012)
Global warming has led to a significant increase in Greenland ice sheet (GrIS) melt and runoff since 1990, resulting in escalated export of fresh water and associated sediment to the surrounding North Atlantic and Arctic ...
Atlantic Ocean circulation at the last glacial maximum : inferences from data and models
(Massachusetts Institute of Technology, 2012)
This thesis focuses on ocean circulation and atmospheric forcing in the Atlantic Ocean at the Last Glacial Maximum (LGM, 18-21 thousand years before present). Relative to the pre-industrial climate, LGM atmospheric CO₂ ...
Earthquake behavior and structure of oceanic transform faults
(Massachusetts Institute of Technology, 2012)
Oceanic transform faults that accommodate strain at mid-ocean ridge offsets represent a unique environment for studying fault mechanics. Here, I use seismic observations and models to explore how fault structure affects ...