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New insights into the marine oxygen cycle from manganese oxide minerals and reactive oxygen species
(Massachusetts Institute of Technology, 2020)
The redox cycling of oxygen between O₂, water, and intermediate redox states including hydrogen peroxide and superoxide, has profound impact on the availability and distribution of dissolved O₂, the habitability of the ...
Seismic and numerical constraints on the formation and evolution of ocean lithosphere
(Massachusetts Institute of Technology, 2019)
This thesis explicates aspects of the basic structure of oceanic lithosphere that are shaped by the processes that form the lithosphere. The strength of lithospheric plates relative to the underlying mantle enables the ...
Characterizing cobalamin cycling by Antarctic marine microbes across multiple scales
(Massachusetts Institute of Technology, 2020)
Highly productive marine microbial communities in the coastal Southern Ocean sustain the broader Antarctic ecosystem and play a key role in Earth's climate via the biological pump. Regional phytoplankton growth is primarily ...
The heterogeneity and volatile content of Earth's mantle, magmas and crust
(Massachusetts Institute of Technology, 2021)
This thesis explores the volatile content of the mantle, subducted oceanic crust, and arc magmas as well as the structure of slow spreading ocean crust and the heterogeneity of Earth's upper mantle. In Chapter 2, I directly ...
Diagnosing the variability in temperature and velocity in the Middle Atlantic Bight
(Massachusetts Institute of Technology, 2021)
Observations of hydrographic and dynamical properties on the Middle Atlantic Bight shelf document strong variability at time scales spanning events that last a few days to century long trends. This thesis studies individual ...
Geophysical and geochemical constraints on submarine volcanic processes
(Massachusetts Institute of Technology, 2019)
Submarine volcanic systems form new oceanic crust, host unique chemosynthetic ecosystems, concentrate rare metals, and provide a conduit for chemical transfer from the Earth's interior to hydrosphere. Although our understanding ...
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 ...
Lagrangian dispersion and deformation in submesoscale flows
(Massachusetts Institute of Technology, 2019)
Submesoscale currents, with horizontal length scales of 1-20 km, are an important element of upper ocean dynamics. These currents play a crucial role in the horizontal and vertical redistribution of tracers, the cascade ...
Stratified and stirred : monsoon freshwater in the Bay of Bengal
(Massachusetts Institute of Technology, 2019)
Submesoscale ocean dynamics and instabilities, with characteristic scales 0.1-10 kin, can play a critical role in setting the ocean's surface boundary layer thickness and associated density stratification. Submesoscale ...
U-Th dating of lacustrine carbonates
(Massachusetts Institute of Technology, 2020)
Carbonates are prevalent in many modern and ancient lacustrine settings, but reconstructions of past lake levels or environments from such materials have been hindered by poor chronology. Uranium-thorium (U-Th) dating has ...