Glacially-controlled variations in the biological pump of the Ross Sea in the Mid-to-Late Pliocene

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dc.contributor.advisorAsh, Jeanineen_US
dc.contributor.advisorMasiello, Carrieen_US
dc.creatorNirenberg, Jareden_US
dc.date.accessioned2020-08-21T18:36:21Zen_US
dc.date.available2020-08-21T18:36:21Zen_US
dc.date.issued2020-05en_US
dc.descriptionAn undergraduate thesis submitted in partial application for the Honors degree in Earth Sciences.en_US
dc.description.abstractThe mid-to-late Pliocene (~3.3 – 2.5 Ma) is an intriguing period for investigating Earth’s past climate dynamics as a potential analogue for future warmth due to anthropogenic climate change. In the Southern Ocean, the Ross Sea and the adjacent West Antarctic Ice Sheet exert significant influence on global climate through their roles in carbon cycle processes, deep ocean circulation, and eustatic sea level. Previous ocean drilling records have shown that the marine-based West Antarctic Ice Sheet exhibited highly dynamic behavior in the Pliocene and responded to cyclical variations in Earth’s orbital geometry. However, fundamental questions remain regarding the biogeochemical response of Southern Ocean marine productivity to changes in ice sheet dynamics and sea ice cover. The International Ocean Discovery Program’s Expedition 374 to the Ross Sea (2018) recovered multiple sediment cores, including those from Site U1524 on the continental rise. I present a 900,000 year record of the carbon and nitrogen content in bulk sediment in the Pliocene-aged cores from Hole U1524A. This record shows the response of carbon export from the Ross Sea continental shelf to orbital and longer-term forcings of the West Antarctic Ice Sheet and global climate. From 3.3 to 3.0 million years ago, I observe a gradual, non-monotonic increase in organic carbon to nitrogen ratios, followed by a decrease from 3.0 to 2.8 million years ago. Sediment color reflectance measurements, implying changes in surface water productivity, are tightly anti-correlated with organic carbon to nitrogen ratios between 3.3 and 3.0 million years ago, but are positively correlated between 3.0 and 2.8 million years ago. I discuss these trends in the context of concurrent sedimentology, physical oceanography, and ice-sheet dynamics. Finally, I note that potential diagenetic effects limit interpretation of this record, and I suggest that bulk carbon and nitrogen stable isotope measurements combined with compound-specific analyses may provide more insight into carbon and nitrogen cycle dynamics during the mid-to-late Pliocene.en_US
dc.format.extent37 ppen_US
dc.identifier.citationNirenberg, Jared. "Glacially-controlled variations in the biological pump of the Ross Sea in the Mid-to-Late Pliocene." Undergraduate thesis, Rice University, 2020. ‪https://doi.org/10.25611/5098-yx37‬.en_US
dc.identifier.doi‪https://doi.org/10.25611/5098-yx37‬en_US
dc.identifier.urihttps://hdl.handle.net/1911/109255en_US
dc.language.isoengen_US
dc.publisherRice Universityen_US
dc.rightsCopyright is held by author.en_US
dc.subjectRoss Seaen_US
dc.subjectPlioceneen_US
dc.subjectWest Antarctic Ice Sheeten_US
dc.subjectbiogeochemistryen_US
dc.subjectsedimentologyen_US
dc.titleGlacially-controlled variations in the biological pump of the Ross Sea in the Mid-to-Late Plioceneen_US
dc.type.dcmiTexten_US
dc.type.genreThesisen_US
thesis.degree.departmentEarth, Environmental, and Planetary Sciencesen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelUndergraduateen_US
thesis.degree.nameHonor Thesisen_US
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