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Now showing items 1-10 of 12
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 ...
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 ...
Capturing dynamics of inorganic carbon fluxes from diurnal to decadal timescales
(Massachusetts Institute of Technology, 2017)
The marine carbon cycle plays an important role in regulating Earth's climate. The vastness of the open ocean and the large variability in the coastal ocean provide obstacles to accurately quantify storage and transport ...
Physics of diurnal warm layers : turbulence, internal waves, and lateral mixing
(Massachusetts Institute of Technology, 2017)
The daily heating of the ocean by the sun can create a stably stratified near-surface layer when the winds are slight and solar insolation is strong. This type of shallow stable layer is called a Diurnal Warm Layer (DWL). ...
Influence of meltwater on Greenland Ice Sheet dynamics
(Massachusetts Institute of Technology, 2017)
Seasonal fluxes of meltwater control ice-flow processes across the Greenland Ice Sheet ablation zone and subglacial discharge at marine-terminating outlet glaciers. With the increase in annual ice sheet meltwater production ...
Ecosystem metabolism in salt marsh tidal creeks and ponds : applying triple oxygen isotopes and other gas tracers to novel environments
(Massachusetts Institute of Technology, 2017)
Salt marshes are physically, chemically, and biologically dynamic environments found globally at temperate latitudes. Tidal creeks and marshtop ponds may expand at the expense of productive grass-covered marsh platform. ...
Geophysical and petrological constraints on ocean plate dynamics
(Massachusetts Institute of Technology, 2017)
This thesis investigates the formation and subsequent motion of oceanic lithospheric plates through geophysical and petrological methods. Ocean crust and lithosphere forms at mid-ocean ridges as the underlying asthenosphere ...
Coral biomineralization, climate proxies and the sensitivity of coral reefs to CO₂-driven climate
(Massachusetts Institute of Technology, 2017)
Scleractinian corals extract calcium (Ca²⁺) and carbonate (CO₃²⁻) ions from seawater to construct their calcium carbonate (CaCO₃) skeletons. Key to the coral biomineralization process is the active elevation of the CO₃²⁻ ...
The cobalt cycle in the tropical Pacific Ocean
(Massachusetts Institute of Technology, 2017)
Although over a dozen elements are needed to support phytoplankton growth, only a few are considered to be growth-limiting. As the central atom in vitamin B12, cobalt is crucial for metabolism, but its status as a limiting ...