Search
Now showing items 1-10 of 21
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 ...
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 ...
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 ...
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 ...
Experimental studies of melting and crystallization processes in planetary interiors
(Massachusetts Institute of Technology, 2011)
Melting and crystallization processes on the Earth and Moon are explored in this thesis, and the topics of melt generation, transport, and crystallization are discussed in three distinct geologic environments: the Moon's ...
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 ...
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 ...
Constraining circulation changes through the last deglaciation with deep-sea coral radiocarbon and sedimentary ²³¹Pa/²³⁰Th
(Massachusetts Institute of Technology, 2012)
Radioactive isotopes can be used in paleoceanography both for dating samples and as tracers of ocean processes. Here I use radiocarbon and uranium series isotopes to investigate the ocean's role in climate change over the ...