High latitude controls on the evolution of eastern equatorial Pacific oceanography and climate since the last glacial period

Bova, Samantha C.

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Year:: 2017
Contributor:: Bova, Samantha C (creator); Herbert, Timothy (Director); Fox-Kemper, Baylor (Reader); Clemens, Steven (Reader); Fischer, Karen (Reader); Lynch-Stieglitz, Jean (Reader); Brown University. Geological Sciences (sponsor)
Genre:: theses
Subject:: paleoceanography; carbon cycle; deglaciation; rapid climate change
Extent:: 27, 281 p.
DOI: https://doi.org/10.7301/Z0P26WKM

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Abstract:: Dynamical shifts in the behavior of the Eastern Equatorial Pacific Ocean (EEP) likely amplify changes to the global climate system through their control on heat, water vapor, and carbon exchange with the atmosphere. The physical oceanography and patterns of wind forcing across the region give rise to a uniquely strong link between cool, carbon-rich subsurface intermediate waters and warm, tropical surface waters. The result is a net transfer of heat from the atmosphere into the ocean, elevated rates of primary production, and the release of marine CO2 to the atmosphere. It is therefore critical to understand what controls the efficiency of exchange between intermediate and surface waters in the EEP. In this dissertation I evaluate the relative role of tropical versus high latitude forcing on the evolution of the EEP since the last glacial period, during the transition from the Last Glacial Maximum (LGM) to the current interglacial. I reconstruct the paleo-circulation, temperature, salinity, and nutrient content of EEP intermediate and surface water masses using multiple proxy indicators, including the stable isotopic signature of benthic foraminiferal shells, organic biomarkers, and nannofossil abundances. The first three chapters investigate the role of subsurface water masses, formed in the high latitudes, in driving change in the EEP from the bottom to the top of the water column. I find that the delivery of heat and carbon from the high southern and northern latitudes to the base of the EEP water column during the last deglaciation led to significant changes in regional stratification and CO2 outgassing. Furthermore, it is likely that the EEP was a key conduit for the return of glacially isolated carbon back to the atmosphere during deglaciation. The final two chapters explore the surface ocean response to deglacial climate change and reflect a mixed influence of high-latitude change driven from below and top-down forcing driven by local shifts in the winds. Altogether, this body of work demonstrates a primary role for high-latitude climate in shaping the EEP since the last glacial period.
Notes:: Thesis (Ph.D.)--Brown University, 2017

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Rights: In Copyright
Restrictions on Use: Collection is open for research.

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Bova, Samantha C., "High latitude controls on the evolution of eastern equatorial Pacific oceanography and climate since the last glacial period" (2017). Earth, Environmental and Planetary Sciences Theses and Dissertations. Brown Digital Repository. Brown University Library. https://doi.org/10.7301/Z0P26WKM

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Earth, Environmental and Planetary Sciences Theses and Dissertations

Theses and Dissertations for the Earth, Environmental and Planetary Sciences department.
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