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Abrupt climate change in the Atlantic Ocean during the last 20,000 years : insights from multi-element analysis of benthic and planktic foraminifera and coupled OA-GCM
(Massachusetts Institute of Technology, 2005)
Minor and trace element records of planktic and benthic foraminifera from Atlantic sediment cores, as well as output from a coupled OAGCM, were used to investigate the magnitude and distribution of the oceanic response to ...
The relationship between iron and nitrogen fixation in Trichodesmium spp.
(Massachusetts Institute of Technology, 2009)
Trichodesmium spp. are considered the dominant nitrogen (N) fixing cyanobacteria in tropical and subtropical oceans, regimes frequently characterized by low iron (Fe). Limited information exists about what levels of Fe ...
Overflows and upper ocean interactions : a mechanism for the Azores current
(Massachusetts Institute of Technology, 2006)
The oceanic response to overflows is explored using a two-layer isopycnal model. Overflows are a major source of the dense water of the global deep ocean, originating from only a few marginal seas. They enter the open ocean ...
Seismic and magnetic constraints on the strucutre of upper oceanic crust and fast and slow spreading ridges
(Massachusetts Institute of Technology, 1998)
The upper ocean crust contains a comprehensive record of the shallow geological processes active along the world's mid-ocean ridge system. This thesis examines the magnetic and seismic structure of the upper crust at two ...
Observations and modeling of wave-acceleration-induced sediment transport in the surfzone
(Massachusetts Institute of Technology, 2004)
Onshore sediment transport and sandbar migration are important to the morphological evolution of beaches, but are not understood well. Here, a new model that accounts for accelerations of wave-orbital velocities predicts ...
Centennial-scale elemental and isotopic variability in the tropical and subtropical North Atlantic Ocean
(Massachusetts Institute of Technology, 2002)
The marine geochemistry of the North Atlantic Ocean varies on decadal to centennial time scales, a consequence of natural and anthropogenic forcing. Surface corals provide a useful geochemical archive to quantify past mixed ...
Petrologic and microstructural constraints on focused melt transport in dunites and the rheology of the shallow mantle
(Massachusetts Institute of Technology, 2004)
Observations at mid-ocean ridges indicate that magmas are focused to the ridge axis by a network of porous dunites in near chemical isolation. This thesis investigates several of the outstanding questions regarding the ...
The East Greenland Coastal Current : its structure, variability, and large-scale impact
(Massachusetts Institute of Technology, 2008)
The subtidal circulation of the southeast Greenland shelf is described using a set of high resolution hydrographic and velocity transects occupied in summer 2004. The main feature present is the East Greenland Coastal ...
The temporal dynamics of terrestrial organic matter transfer to the oceans : initial assessment and application
(Massachusetts Institute of Technology, 2007)
This thesis employs compound-specific stable carbon and radiocarbon isotopic analysis of organic biomarkers to (a) resolve petrogenic from pre-aged vascular plant organic carbon (OC) in continental margin sediments, (b) ...
Cross-shelf circulation and momentum and heat balances over the inner continental shelf near Martha's Vineyard, Massachusetts
(Massachusetts Institute of Technology, 2007)
The water circulation and evolution of water temperature over the inner continental shelf are investigated using observations of water velocity, temperature, density, and bottom pressure; surface gravity waves; wind stress; ...