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Now showing items 31-40 of 83
The production and fate of nitrogen species in deep-sea hydrothermal environments
(Massachusetts Institute of Technology, 2019)
Nitrogen (N) species in hydrothermal vent fluids serve as both a nutrient and energy source for the chemosynthetic ecosystems surrounding deep-sea vents. While numerous pathways have been identified in which N-species can ...
Linking microbial metabolism and organic matter cycling through metabolite distributions in the ocean
(Massachusetts Institute of Technology, 2017)
Key players in the marine carbon cycle are the ocean-dwelling microbes that fix, remineralize, and transform organic matter. Many of the small organic molecules in the marine carbon pool have not been well characterized ...
Capturing dynamics of inorganic carbon fluxes from diurnal to decadal timescales
(Massachusetts Institute of Technology, 2017)
The marine carbon cycle plays an important role in regulating Earth's climate. The vastness of the open ocean and the large variability in the coastal ocean provide obstacles to accurately quantify storage and transport ...
Geochemical controls on the distribution and composition of biogenic and sedimentary carbon
(Massachusetts Institute of Technology, 2017)
Organic carbon (OC) preserved in marine sediments acts as a reduced carbon sink that balances the global carbon cycle. Understanding the biogeochemical mechanisms underpinning the balance between OC preservation and ...
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 ...
Dynamics of Greenland's glacial fjords
(Massachusetts Institute of Technology, 2016)
Glacial fjords form conduits between glaciers of the Greenland Ice Sheet and the North Atlantic. They are the gateways for importing oceanic heat to melt ice and for exporting meltwater into the ocean. Submarine melting ...
Aridification of the Indian subcontinent during the Holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations
(Massachusetts Institute of Technology, 2012)
The Indian monsoon affects the livelihood of over one billion people. Despite the importance of climate to society, knowledge of long-term monsoon variability is limited. This thesis provides Holocene records of monsoon ...
An investigation of basin-scale controls on upper ocean export and remineralization
(Massachusetts Institute of Technology, 2018)
The biological carbon pump (BCP) helps to moderate atmospheric carbon dioxide levels by bringing carbon to the deep ocean, where it can be sequestered on timescales of centuries to millennia. Climate change is predicted ...
Water and volatile element accretion to the inner planets
(Massachusetts Institute of Technology, 2018)
This thesis investigates the timing and source(s) of water and volatile elements to the inner solar system by studying the basaltic meteorites angrites and eucrites. In chapters 2 and 3, I present the results from angrite ...
Greenlandic ice archives of North Atlantic Common Era climate
(Massachusetts Institute of Technology, 2019)
The Common Era (A.D. 1- present) represents a crucial period for climatic studies, documenting the timespan over which human activities have become an increasingly domineering force in shaping Earth's landscape, climate, ...