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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 ...
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 ...
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 ...
Protein regulation in Trichodesmium and other marine bacteria : observational and interpretive biomarkers of biogeochemical processes
(Massachusetts Institute of Technology, 2020)
Marine microbes play key roles in global biogeochemistry by mediating chemical transformations and linking nutrient cycles to one another. A major goal in oceanography is to predict the activity of marine microbes across ...
Finescale abyssal turbulence : sources and modeling
(Massachusetts Institute of Technology, 2020)
A detailed understanding of the intensity and three-dimensional spatial distribution of diabatic abyssal turbulence is germane to understanding the abyssal branch of the global overturning circulation. This thesis addresses ...
Investigating Mexican paleoclimate with precisely dated speleothems
(Massachusetts Institute of Technology, 2020)
Speleothems, or sedimentary rocks formed in caves, act as valuable archives of past climate change due to their suitability for U-series dating and high-resolution proxy analysis. These records can provide insights into ...
High resolution sedimentary archives of past millennium hurricane activity in the Bahama Archipelago
(Massachusetts Institute of Technology, 2020)
Atlantic hurricanes threaten growing coastal populations along the U.S. coastline and in the Caribbean islands. Unfortunately, little is known about the forces that alter hurricane activity on multi-decadal to centennial ...
The role of zooplankton in regulating carbon export and phytoplankton community structure : integrating models and observations
(Massachusetts Institute of Technology, 2021)
In this thesis, I explore two topics in plankton ecology with a combination of models and observations. First, I investigate the contribution of zooplankton diel vertical migration (DVM) to the vertical flux of carbon as ...