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Nitrogen cycling in oxygen deficient zones : insights from [delta]¹⁵N and [delta]¹⁸O of nitrite and nitrate
(Massachusetts Institute of Technology, 2013)
The stable isotopes, [delta]¹⁵N and [delta]¹⁸O, of nitrite and nitrate can be powerful tools used to interpret nitrogen cycling in the ocean. They are particularly useful in regions of the ocean where there are multiple ...
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 ...
The effects of ocean eddies on tropical cyclones
(Massachusetts Institute of Technology, 2012)
The purpose of this study is to understand the interactions of tropical cyclones with ocean eddies. In particular we examine the influence of a cold-core eddy on the cold wake formed during the passage of Typhoon Fanapi ...
Seismic constraints on the processes and consequences of secondary igneous evolution of Pacific oceanic lithosphere
(Massachusetts Institute of Technology, 2016)
This thesis examines the structure of Pacific oceanic lithosphere that has been modified by post-formation magmatism in order to better understand the processes of secondary magmatic evolution of the lithosphere, which can ...
Microbial interactions associated with biofilms attached to Trichodesmium spp. and detrital particles in the ocean
(Massachusetts Institute of Technology, 2010)
Quorum sensing (QS) via acylated homoserine lactones (AHLs) was discovered in the ocean, yet little is known about its role in the ocean beyond its involvement in certain symbiotic interactions. The objectives of this ...
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 ...
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 ...
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 ...
Reconstructing deglacial ocean ventilation using radiocarbon : data and inverse modeling
(Massachusetts Institute of Technology, 2017)
Significant changes occurred during the last deglaciation (roughly 10-20 thousand years (ka) before present) throughout the climate system. The ocean is a large reservoir of carbon and heat, however, its role during the ...
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 ...