Orbital-scale controls on biogenic silica accumulation in the Indian Sector of the Southern Ocean over the past 600,000 years
Variations in Earth’s orbital geometry and relative location to the Sun have influenced climate throughout geologic time. These cycles include orbital eccentricity, obliquity, and precession. Combined, these parameters influence the distribution of radiative forcing received by each latitude on Eart...
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ftunivdelaware:oai:udspace.udel.edu:19716/28347 2023-06-11T04:07:05+02:00 Orbital-scale controls on biogenic silica accumulation in the Indian Sector of the Southern Ocean over the past 600,000 years Kaiser, Emily Ann 2020-09-20T19:03:38Z application/pdf https://udspace.udel.edu/handle/19716/28347 en eng University of Delaware https://login.udel.idm.oclc.org/login?url=https://www.proquest.com/dissertations-theses/orbital-scale-controls-on-biogenic-silica/docview/2451884488/se-2?accountid=10457 1227031953 https://udspace.udel.edu/handle/19716/28347 Biogenic silica Orbital-scale Paleoceanography Pleistocene Southern Ocean Stratification Thesis 2020 ftunivdelaware 2023-05-01T12:58:19Z Variations in Earth’s orbital geometry and relative location to the Sun have influenced climate throughout geologic time. These cycles include orbital eccentricity, obliquity, and precession. Combined, these parameters influence the distribution of radiative forcing received by each latitude on Earth (insolation), which has been linked to climate warming and cooling. Records of climate, such as oxygen isotopes, display variations in concert with the amount of radiative forcing received by Earth. Another factor that plays into glacial/interglacial climate is the amount of greenhouse gases in the atmosphere. Previous studies, utilizing ice cores, have revealed that the concentrations of greenhouse gas, such as carbon dioxide, in the atmosphere vary over glacial/interglacial timescales. One hypothesis to explain the difference between low glacial CO2 and high interglacial CO2 relies on stratification within the Southern Ocean (e.g., Sigman & Boyle, 2000). In this study, I hypothesize that atmospheric CO2 levels are regulated by changes in Southern Ocean stratification. For example, interglacial climates have high atmospheric CO2 levels due to a well-ventilated Southern Ocean. Within the modern Antarctic Zone of the Southern Ocean, nutrient- rich deep waters are pulled to the surface via Ekman pumping (upwelling), fueling one of the most biologically productive regions of the world’s oceans. These deepwater masses that are upwelled also contain dissolved CO2. On glacial/interglacial timescales, Southern Ocean stratification has been linked to global climate change as a mechanism that regulates atmospheric CO2 levels. ☐ Downcore variations in opal production are generally used as a proxy for upwelling throughout geologic time. Typically, these records are restricted to the past glacial/interglacial cycle due to the vast ability of sedimentological records spanning recent geologic time. In this study, I expand understanding of Southern Ocean stratification, evidenced by changes in upwelling, over the past 600 kyr ... Thesis Antarc* Antarctic Southern Ocean The University of Delaware Library Institutional Repository Antarctic Southern Ocean Indian |
institution |
Open Polar |
collection |
The University of Delaware Library Institutional Repository |
op_collection_id |
ftunivdelaware |
language |
English |
topic |
Biogenic silica Orbital-scale Paleoceanography Pleistocene Southern Ocean Stratification |
spellingShingle |
Biogenic silica Orbital-scale Paleoceanography Pleistocene Southern Ocean Stratification Kaiser, Emily Ann Orbital-scale controls on biogenic silica accumulation in the Indian Sector of the Southern Ocean over the past 600,000 years |
topic_facet |
Biogenic silica Orbital-scale Paleoceanography Pleistocene Southern Ocean Stratification |
description |
Variations in Earth’s orbital geometry and relative location to the Sun have influenced climate throughout geologic time. These cycles include orbital eccentricity, obliquity, and precession. Combined, these parameters influence the distribution of radiative forcing received by each latitude on Earth (insolation), which has been linked to climate warming and cooling. Records of climate, such as oxygen isotopes, display variations in concert with the amount of radiative forcing received by Earth. Another factor that plays into glacial/interglacial climate is the amount of greenhouse gases in the atmosphere. Previous studies, utilizing ice cores, have revealed that the concentrations of greenhouse gas, such as carbon dioxide, in the atmosphere vary over glacial/interglacial timescales. One hypothesis to explain the difference between low glacial CO2 and high interglacial CO2 relies on stratification within the Southern Ocean (e.g., Sigman & Boyle, 2000). In this study, I hypothesize that atmospheric CO2 levels are regulated by changes in Southern Ocean stratification. For example, interglacial climates have high atmospheric CO2 levels due to a well-ventilated Southern Ocean. Within the modern Antarctic Zone of the Southern Ocean, nutrient- rich deep waters are pulled to the surface via Ekman pumping (upwelling), fueling one of the most biologically productive regions of the world’s oceans. These deepwater masses that are upwelled also contain dissolved CO2. On glacial/interglacial timescales, Southern Ocean stratification has been linked to global climate change as a mechanism that regulates atmospheric CO2 levels. ☐ Downcore variations in opal production are generally used as a proxy for upwelling throughout geologic time. Typically, these records are restricted to the past glacial/interglacial cycle due to the vast ability of sedimentological records spanning recent geologic time. In this study, I expand understanding of Southern Ocean stratification, evidenced by changes in upwelling, over the past 600 kyr ... |
format |
Thesis |
author |
Kaiser, Emily Ann |
author_facet |
Kaiser, Emily Ann |
author_sort |
Kaiser, Emily Ann |
title |
Orbital-scale controls on biogenic silica accumulation in the Indian Sector of the Southern Ocean over the past 600,000 years |
title_short |
Orbital-scale controls on biogenic silica accumulation in the Indian Sector of the Southern Ocean over the past 600,000 years |
title_full |
Orbital-scale controls on biogenic silica accumulation in the Indian Sector of the Southern Ocean over the past 600,000 years |
title_fullStr |
Orbital-scale controls on biogenic silica accumulation in the Indian Sector of the Southern Ocean over the past 600,000 years |
title_full_unstemmed |
Orbital-scale controls on biogenic silica accumulation in the Indian Sector of the Southern Ocean over the past 600,000 years |
title_sort |
orbital-scale controls on biogenic silica accumulation in the indian sector of the southern ocean over the past 600,000 years |
publisher |
University of Delaware |
publishDate |
2020 |
url |
https://udspace.udel.edu/handle/19716/28347 |
geographic |
Antarctic Southern Ocean Indian |
geographic_facet |
Antarctic Southern Ocean Indian |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
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