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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 ...
Geochemistry of deep-sea hydrothermal vent fluids from the Mid-Cayman Rise, Caribbean Sea
(Massachusetts Institute of Technology, 2015)
This thesis examines the controls on organic, inorganic, and volatile species distributions in hydrothermal fluids venting at Von Damm and Piccard, two recently discovered vent fields at the ultra slow spreading Mid-Cayman ...
Testing the ancient marine redox record from oxygenic photosynthesis to photic zone euxina
(Massachusetts Institute of Technology, 2015)
Tracing the evolution of Earth's 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, ...
Biogeochemical and phylogenetic signals of Proterozoic and Phanerozoic microbial metabolisms
(Massachusetts Institute of Technology, 2018)
Life is ubiquitous in the environment and an important mediator of Earth's carbon cycle, but quantifying the contribution of microbial biomass and its metabolic fluxes is difficult, especially in spatially and temporally-remote ...
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 ...
Late Quaternary climate variability and terrestrial carbon cycling in tropical South America
(Massachusetts Institute of Technology, 2016)
Characterizing global and regional climate variability and climate-carbon cycle interactions in the past provides critical context for evaluating present and future climate trends. In this thesis, I use stable isotope and ...