An investigation of basin-scale controls on upper ocean export and remineralization
Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2018. Cataloged from PDF version of thesis. Includes bibliographical re...
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ftmit:oai:dspace.mit.edu:1721.1/115781 2023-05-15T15:05:53+02:00 An investigation of basin-scale controls on upper ocean export and remineralization Black, Erin E Ken O. Buesseler. Woods Hole Oceanographic Institution. Joint Program in Oceanography/Applied Ocean Science and Engineering Woods Hole Oceanographic Institution Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences p --- 2018 269 pages application/pdf http://hdl.handle.net/1721.1/115781 eng eng Massachusetts Institute of Technology http://hdl.handle.net/1721.1/115781 1036987758 MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission. http://dspace.mit.edu/handle/1721.1/7582 MIT Joint Program in Oceanography/Applied Ocean Science and Engineering Earth Atmospheric and Planetary Sciences Woods Hole Oceanographic Institution Carbon Climatic changes Ocean Thesis 2018 ftmit 2022-01-17T18:21:42Z Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2018. Cataloged from PDF version of thesis. Includes bibliographical references. The biological carbon pump (BCP) helps to moderate atmospheric carbon dioxide levels by bringing carbon to the deep ocean, where it can be sequestered on timescales of centuries to millennia. Climate change is predicted to decrease the efficiency of the global BCP, however, the magnitude and timescale of this shift is largely uncertain and will likely impact some areas of the global ocean more significantly than others. Therefore, it is imperative that we (1) accurately quantify surface export and remineralization of particulate organic carbon (POC) via the BCP over large regions of the global ocean, (2) examine the factors controlling these POC fluxes and their variability, which includes the cycling of biologically-relevant trace metals, and (3) establish if and how the BCP is changing over time. This thesis focuses on addressing various aspects of these objectives using the 234Th- 238U method across basin-scale GEOTRACES transects. First, the export and remineralization of POC were examined across large gradients in productivity, upwelling, community structure, and dissolved oxygen in the southeastern tropical Pacific Ocean. Although low oxygen zones are traditionally thought to have decreased POC flux attenuation relative to other regions of the global ocean and the low oxygen Pacific locations followed this pattern, regions that were functionally anoxic had enhanced attenuation in the upper 400 m. Second, trace metal export and remineralization were quantified across the Pacific transect. Because many trace metals are necessary for the metabolic functions of marine organisms and can co-limit marine productivity, the controls on the cycling of trace metals in the upper ocean were examined. Lastly, POC export was determined across two transects in the Western Arctic Ocean, where light and nutrient availability drive the biological pump. Upper ocean export estimates in the central basin did not reflect a substantial change in the biological pump compared to studies from the last three decades, however, an extensive maximum in 234Th relative to 238U deeper in the water column indicated that rapid vertical transport had occurred, which could suggest a more efficient biological pump in the Arctic Ocean. by Erin E. Black. Ph. D. Thesis Arctic Arctic Ocean Climate change DSpace@MIT (Massachusetts Institute of Technology) Arctic Arctic Ocean Central Basin ENVELOPE(43.000,43.000,73.500,73.500) Pacific |
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Open Polar |
collection |
DSpace@MIT (Massachusetts Institute of Technology) |
op_collection_id |
ftmit |
language |
English |
topic |
Joint Program in Oceanography/Applied Ocean Science and Engineering Earth Atmospheric and Planetary Sciences Woods Hole Oceanographic Institution Carbon Climatic changes Ocean |
spellingShingle |
Joint Program in Oceanography/Applied Ocean Science and Engineering Earth Atmospheric and Planetary Sciences Woods Hole Oceanographic Institution Carbon Climatic changes Ocean Black, Erin E An investigation of basin-scale controls on upper ocean export and remineralization |
topic_facet |
Joint Program in Oceanography/Applied Ocean Science and Engineering Earth Atmospheric and Planetary Sciences Woods Hole Oceanographic Institution Carbon Climatic changes Ocean |
description |
Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2018. Cataloged from PDF version of thesis. Includes bibliographical references. The biological carbon pump (BCP) helps to moderate atmospheric carbon dioxide levels by bringing carbon to the deep ocean, where it can be sequestered on timescales of centuries to millennia. Climate change is predicted to decrease the efficiency of the global BCP, however, the magnitude and timescale of this shift is largely uncertain and will likely impact some areas of the global ocean more significantly than others. Therefore, it is imperative that we (1) accurately quantify surface export and remineralization of particulate organic carbon (POC) via the BCP over large regions of the global ocean, (2) examine the factors controlling these POC fluxes and their variability, which includes the cycling of biologically-relevant trace metals, and (3) establish if and how the BCP is changing over time. This thesis focuses on addressing various aspects of these objectives using the 234Th- 238U method across basin-scale GEOTRACES transects. First, the export and remineralization of POC were examined across large gradients in productivity, upwelling, community structure, and dissolved oxygen in the southeastern tropical Pacific Ocean. Although low oxygen zones are traditionally thought to have decreased POC flux attenuation relative to other regions of the global ocean and the low oxygen Pacific locations followed this pattern, regions that were functionally anoxic had enhanced attenuation in the upper 400 m. Second, trace metal export and remineralization were quantified across the Pacific transect. Because many trace metals are necessary for the metabolic functions of marine organisms and can co-limit marine productivity, the controls on the cycling of trace metals in the upper ocean were examined. Lastly, POC export was determined across two transects in the Western Arctic Ocean, where light and nutrient availability drive the biological pump. Upper ocean export estimates in the central basin did not reflect a substantial change in the biological pump compared to studies from the last three decades, however, an extensive maximum in 234Th relative to 238U deeper in the water column indicated that rapid vertical transport had occurred, which could suggest a more efficient biological pump in the Arctic Ocean. by Erin E. Black. Ph. D. |
author2 |
Ken O. Buesseler. Woods Hole Oceanographic Institution. Joint Program in Oceanography/Applied Ocean Science and Engineering Woods Hole Oceanographic Institution Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
format |
Thesis |
author |
Black, Erin E |
author_facet |
Black, Erin E |
author_sort |
Black, Erin E |
title |
An investigation of basin-scale controls on upper ocean export and remineralization |
title_short |
An investigation of basin-scale controls on upper ocean export and remineralization |
title_full |
An investigation of basin-scale controls on upper ocean export and remineralization |
title_fullStr |
An investigation of basin-scale controls on upper ocean export and remineralization |
title_full_unstemmed |
An investigation of basin-scale controls on upper ocean export and remineralization |
title_sort |
investigation of basin-scale controls on upper ocean export and remineralization |
publisher |
Massachusetts Institute of Technology |
publishDate |
2018 |
url |
http://hdl.handle.net/1721.1/115781 |
op_coverage |
p --- |
long_lat |
ENVELOPE(43.000,43.000,73.500,73.500) |
geographic |
Arctic Arctic Ocean Central Basin Pacific |
geographic_facet |
Arctic Arctic Ocean Central Basin Pacific |
genre |
Arctic Arctic Ocean Climate change |
genre_facet |
Arctic Arctic Ocean Climate change |
op_relation |
http://hdl.handle.net/1721.1/115781 1036987758 |
op_rights |
MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission. http://dspace.mit.edu/handle/1721.1/7582 |
op_rightsnorm |
MIT |
_version_ |
1766337567279546368 |