Southern Ocean control on atmospheric CO2 changes across late-Pliocene Marine Isotope Stage M2
During the Pliocene, atmospheric CO 2 concentrations ( p CO 2 ) were similar to today’s and global average temperature was ~3 °C higher. However, the relationships and phasing between variability in climate and p CO 2 on orbital time scales are not well understood. Specifically, qu...
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ftcopernicus:oai:publications.copernicus.org:cpd119816 2024-06-23T07:56:55+00:00 Southern Ocean control on atmospheric CO2 changes across late-Pliocene Marine Isotope Stage M2 Hou, Suning Toebrock, Leonie Linden, Mart Rothstegge, Fleur Ziegler, Martin Lourens, Lucas J. Bijl, Peter K. 2024-05-13 application/pdf https://doi.org/10.5194/cp-2024-33 https://cp.copernicus.org/preprints/cp-2024-33/ eng eng doi:10.5194/cp-2024-33 https://cp.copernicus.org/preprints/cp-2024-33/ eISSN: 1814-9332 Text 2024 ftcopernicus https://doi.org/10.5194/cp-2024-33 2024-06-13T01:24:45Z During the Pliocene, atmospheric CO 2 concentrations ( p CO 2 ) were similar to today’s and global average temperature was ~3 °C higher. However, the relationships and phasing between variability in climate and p CO 2 on orbital time scales are not well understood. Specifically, questions remain about the nature of a lag of p CO 2 relative to benthic foraminiferal δ 18 O in the late-Pliocene Marine Isotope Stage M2 (3300 kiloannum ago, ka), which was longer than during the Pleistocene. Here, we present a multi-proxy paleoceanographic reconstruction of the late-Pliocene subantarctic zone, which is today one of the major ocean sinks of atmospheric CO 2 . New dinoflagellate cyst assemblage data is combined with previously published sea surface temperature reconstructions, to reveal past surface conditions, including latitudinal migrations of the subtropical front (STF) over the late-Pliocene at ODP Site 1168, offshore west Tasmania. We observe strong oceanographic variability at the STF over glacial-interglacial timescales, especially across the M2 (3320–3260 ka). By providing tight and independent age constraints from benthic foraminiferal δ 18 O, we find that, much more than benthic δ 18 O or local SST, latitudinal migrations of the STF are tightly coupled to p CO 2 variations across the M2. Specifically, a northerly position of the STF during M2 deglaciation coincides with generally low p CO 2 . We postulate that the efficiency of the Southern Ocean carbon outgassing varied strongly with migrations of the STF, and that is in part accounted for the variability in p CO 2 across M2. Text Southern Ocean Copernicus Publications: E-Journals Southern Ocean |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
During the Pliocene, atmospheric CO 2 concentrations ( p CO 2 ) were similar to today’s and global average temperature was ~3 °C higher. However, the relationships and phasing between variability in climate and p CO 2 on orbital time scales are not well understood. Specifically, questions remain about the nature of a lag of p CO 2 relative to benthic foraminiferal δ 18 O in the late-Pliocene Marine Isotope Stage M2 (3300 kiloannum ago, ka), which was longer than during the Pleistocene. Here, we present a multi-proxy paleoceanographic reconstruction of the late-Pliocene subantarctic zone, which is today one of the major ocean sinks of atmospheric CO 2 . New dinoflagellate cyst assemblage data is combined with previously published sea surface temperature reconstructions, to reveal past surface conditions, including latitudinal migrations of the subtropical front (STF) over the late-Pliocene at ODP Site 1168, offshore west Tasmania. We observe strong oceanographic variability at the STF over glacial-interglacial timescales, especially across the M2 (3320–3260 ka). By providing tight and independent age constraints from benthic foraminiferal δ 18 O, we find that, much more than benthic δ 18 O or local SST, latitudinal migrations of the STF are tightly coupled to p CO 2 variations across the M2. Specifically, a northerly position of the STF during M2 deglaciation coincides with generally low p CO 2 . We postulate that the efficiency of the Southern Ocean carbon outgassing varied strongly with migrations of the STF, and that is in part accounted for the variability in p CO 2 across M2. |
format |
Text |
author |
Hou, Suning Toebrock, Leonie Linden, Mart Rothstegge, Fleur Ziegler, Martin Lourens, Lucas J. Bijl, Peter K. |
spellingShingle |
Hou, Suning Toebrock, Leonie Linden, Mart Rothstegge, Fleur Ziegler, Martin Lourens, Lucas J. Bijl, Peter K. Southern Ocean control on atmospheric CO2 changes across late-Pliocene Marine Isotope Stage M2 |
author_facet |
Hou, Suning Toebrock, Leonie Linden, Mart Rothstegge, Fleur Ziegler, Martin Lourens, Lucas J. Bijl, Peter K. |
author_sort |
Hou, Suning |
title |
Southern Ocean control on atmospheric CO2 changes across late-Pliocene Marine Isotope Stage M2 |
title_short |
Southern Ocean control on atmospheric CO2 changes across late-Pliocene Marine Isotope Stage M2 |
title_full |
Southern Ocean control on atmospheric CO2 changes across late-Pliocene Marine Isotope Stage M2 |
title_fullStr |
Southern Ocean control on atmospheric CO2 changes across late-Pliocene Marine Isotope Stage M2 |
title_full_unstemmed |
Southern Ocean control on atmospheric CO2 changes across late-Pliocene Marine Isotope Stage M2 |
title_sort |
southern ocean control on atmospheric co2 changes across late-pliocene marine isotope stage m2 |
publishDate |
2024 |
url |
https://doi.org/10.5194/cp-2024-33 https://cp.copernicus.org/preprints/cp-2024-33/ |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-2024-33 https://cp.copernicus.org/preprints/cp-2024-33/ |
op_doi |
https://doi.org/10.5194/cp-2024-33 |
_version_ |
1802650311614005248 |