Evidence for elevated alkalinity in the glacial Southern Ocean
An increase in whole ocean alkalinity during glacial periods could account, in part, for the drawdown of atmospheric CO₂ into the ocean. Such an increase was inevitable due to the near elimination of shelf area for the burial of coral reef alkalinity. We present evidence, based on downcore measureme...
| Main Authors: | , , , , |
|---|---|
| Format: | Journal article |
| Language: | English |
| Published: |
American Geophysical Union
2010
|
| Subjects: |
| _version_ | 1826260200459337728 |
|---|---|
| author | Rickaby, R Elderfield, H Roberts, N Hillenbrand, C Mackensen, A |
| author_facet | Rickaby, R Elderfield, H Roberts, N Hillenbrand, C Mackensen, A |
| author_sort | Rickaby, R |
| collection | OXFORD |
| description | An increase in whole ocean alkalinity during glacial periods could account, in part, for the drawdown of atmospheric CO₂ into the ocean. Such an increase was inevitable due to the near elimination of shelf area for the burial of coral reef alkalinity. We present evidence, based on downcore measurements of benthic foraminiferal B/Ca and Mg/Ca from a core in the Weddell Sea, that the deep ocean carbonate ion concentration, [CO²⁻₃], was elevated by ~25 μmol/kg during each glacial period of the last 800 kyr. The heterogeneity of the preservation histories in the different ocean basins reflects control of the carbonate chemistry of the deep glacial ocean in the Atlantic and Pacific by the changing ventilation and chemistry of Weddell Sea waters. These waters are more corrosive than interglacial northern sourced waters but not as undersaturated as interglacial southern sourced waters. Our infrared increase in whole ocean alkalinity can be reconciled with reconstructions of glacial saturation horizon depth and the carbonate budget if carbonate burial rates also increased above the saturation horizon as a result of enhanced pelagic calcification. The Weddell records display low[CO²⁻₃] and act to trigger the deglacial rise in pCO₂. |
| first_indexed | 2024-03-06T19:01:52Z |
| format | Journal article |
| id | oxford-uuid:13d1f9fc-dc09-47c2-9970-604284a4b72f |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T19:01:52Z |
| publishDate | 2010 |
| publisher | American Geophysical Union |
| record_format | dspace |
| spelling | oxford-uuid:13d1f9fc-dc09-47c2-9970-604284a4b72f2022-03-26T10:16:01ZEvidence for elevated alkalinity in the glacial Southern OceanJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:13d1f9fc-dc09-47c2-9970-604284a4b72fEarth sciencesEnglishOxford University Research Archive - ValetAmerican Geophysical Union2010Rickaby, RElderfield, HRoberts, NHillenbrand, CMackensen, AAn increase in whole ocean alkalinity during glacial periods could account, in part, for the drawdown of atmospheric CO₂ into the ocean. Such an increase was inevitable due to the near elimination of shelf area for the burial of coral reef alkalinity. We present evidence, based on downcore measurements of benthic foraminiferal B/Ca and Mg/Ca from a core in the Weddell Sea, that the deep ocean carbonate ion concentration, [CO²⁻₃], was elevated by ~25 μmol/kg during each glacial period of the last 800 kyr. The heterogeneity of the preservation histories in the different ocean basins reflects control of the carbonate chemistry of the deep glacial ocean in the Atlantic and Pacific by the changing ventilation and chemistry of Weddell Sea waters. These waters are more corrosive than interglacial northern sourced waters but not as undersaturated as interglacial southern sourced waters. Our infrared increase in whole ocean alkalinity can be reconciled with reconstructions of glacial saturation horizon depth and the carbonate budget if carbonate burial rates also increased above the saturation horizon as a result of enhanced pelagic calcification. The Weddell records display low[CO²⁻₃] and act to trigger the deglacial rise in pCO₂. |
| spellingShingle | Earth sciences Rickaby, R Elderfield, H Roberts, N Hillenbrand, C Mackensen, A Evidence for elevated alkalinity in the glacial Southern Ocean |
| title | Evidence for elevated alkalinity in the glacial Southern Ocean |
| title_full | Evidence for elevated alkalinity in the glacial Southern Ocean |
| title_fullStr | Evidence for elevated alkalinity in the glacial Southern Ocean |
| title_full_unstemmed | Evidence for elevated alkalinity in the glacial Southern Ocean |
| title_short | Evidence for elevated alkalinity in the glacial Southern Ocean |
| title_sort | evidence for elevated alkalinity in the glacial southern ocean |
| topic | Earth sciences |
| work_keys_str_mv | AT rickabyr evidenceforelevatedalkalinityintheglacialsouthernocean AT elderfieldh evidenceforelevatedalkalinityintheglacialsouthernocean AT robertsn evidenceforelevatedalkalinityintheglacialsouthernocean AT hillenbrandc evidenceforelevatedalkalinityintheglacialsouthernocean AT mackensena evidenceforelevatedalkalinityintheglacialsouthernocean |