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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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
The biogeochemistry of marine nitrous oxide
(Massachusetts Institute of Technology, 2011)
Atmospheric nitrous oxide N₂O concentrations have been rising steadily for the past century as a result of human activities. In particular, human perturbation of the nitrogen cycle has increased the N₂O production rates ...
Lipid biomarkers of coral stress : calibration and exploration
(Massachusetts Institute of Technology, 2011)
Corals are increasingly threatened by warming sea surface temperatures and other anthropogenic changes. The delicate symbiosis between corals and their algal endosymbionts (zooxanthellae) is easily disrupted by thermal ...
Geomicrobiology of nitrogen in a coastal aquifer : isotopic and molecular methods to examine nitrification and denitrification in groundwater
(Massachusetts Institute of Technology, 2010)
Excess nitrogen input is deleterious to coastal waters, resulting in deterioration of the water quality, increases in harmful algal blooms and disease in commercial fish stocks. A significant portion of this nitrogen enters ...
The centennial and millennial variability of the IndoPacific warm pool and the Indonesian Throughflow
(Massachusetts Institute of Technology, 2012)
As the only low-latitude connection between ocean basins, the Indonesian Throughflow allows the direct transmission of heat and salinity between the Pacific and Indian Oceans. Despite its potential importance, the role of ...