Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels
Atmospheric pCO 2 is a critical component of the global carbon system and is considered to be the major control of Earth's past, present, and future climate. Accurate and precise reconstructions of its concentration through geological time are therefore crucial to our understanding of the Earth...
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ftsouthampton:oai:eprints.soton.ac.uk:430074 2023-08-27T04:09:58+02:00 Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels Badger, Marcus P.S. Chalk, Thomas B. Foster, Gavin L. Bown, Paul R. Gibbs, Samantha J. Sexton, Philip F. Schmidt, Daniela N. Pälike, Heiko Mackensen, Andreas Pancost, Richard D. 2019-03-27 text https://eprints.soton.ac.uk/430074/ https://eprints.soton.ac.uk/430074/1/cp_15_539_2019.pdf en English eng https://eprints.soton.ac.uk/430074/1/cp_15_539_2019.pdf Badger, Marcus P.S., Chalk, Thomas B., Foster, Gavin L., Bown, Paul R., Gibbs, Samantha J., Sexton, Philip F., Schmidt, Daniela N., Pälike, Heiko, Mackensen, Andreas and Pancost, Richard D. (2019) Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels. Climate of the Past, 15 (2), 539-554. (doi:10.5194/cp-15-539-2019 <http://dx.doi.org/10.5194/cp-15-539-2019>). cc_by_4 Article PeerReviewed 2019 ftsouthampton https://doi.org/10.5194/cp-15-539-2019 2023-08-03T22:23:48Z Atmospheric pCO 2 is a critical component of the global carbon system and is considered to be the major control of Earth's past, present, and future climate. Accurate and precise reconstructions of its concentration through geological time are therefore crucial to our understanding of the Earth system. Ice core records document pCO 2 for the past 800 kyr, but at no point during this interval were CO2 levels higher than today. Interpretation of older pCO 2 has been hampered by discrepancies during some time intervals between two of the main ocean-based proxy methods used to reconstruct pCO 2 : the carbon isotope fractionation that occurs during photosynthesis as recorded by haptophyte biomarkers (alkenones) and the boron isotope composition (δ 11 B) of foraminifer shells. Here, we present alkenone and δ 11 B-based pCO 2 reconstructions generated from the same samples from the Pliocene and across a Pleistocene glacial- interglacial cycle at Ocean Drilling Program (ODP) Site 999. We find a muted response to pCO 2 in the alkenone record compared to contemporaneous ice core and δ 11 B records, suggesting caution in the interpretation of alkenone-based records at low pCO 2 levels. This is possibly caused by the physiology of CO2 uptake in the haptophytes. Our new understanding resolves some of the inconsistencies between the proxies and highlights that caution may be required when interpreting alkenone-based reconstructions of pCO 2 . Article in Journal/Newspaper ice core University of Southampton: e-Prints Soton Climate of the Past 15 2 539 554 |
institution |
Open Polar |
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University of Southampton: e-Prints Soton |
op_collection_id |
ftsouthampton |
language |
English |
description |
Atmospheric pCO 2 is a critical component of the global carbon system and is considered to be the major control of Earth's past, present, and future climate. Accurate and precise reconstructions of its concentration through geological time are therefore crucial to our understanding of the Earth system. Ice core records document pCO 2 for the past 800 kyr, but at no point during this interval were CO2 levels higher than today. Interpretation of older pCO 2 has been hampered by discrepancies during some time intervals between two of the main ocean-based proxy methods used to reconstruct pCO 2 : the carbon isotope fractionation that occurs during photosynthesis as recorded by haptophyte biomarkers (alkenones) and the boron isotope composition (δ 11 B) of foraminifer shells. Here, we present alkenone and δ 11 B-based pCO 2 reconstructions generated from the same samples from the Pliocene and across a Pleistocene glacial- interglacial cycle at Ocean Drilling Program (ODP) Site 999. We find a muted response to pCO 2 in the alkenone record compared to contemporaneous ice core and δ 11 B records, suggesting caution in the interpretation of alkenone-based records at low pCO 2 levels. This is possibly caused by the physiology of CO2 uptake in the haptophytes. Our new understanding resolves some of the inconsistencies between the proxies and highlights that caution may be required when interpreting alkenone-based reconstructions of pCO 2 . |
format |
Article in Journal/Newspaper |
author |
Badger, Marcus P.S. Chalk, Thomas B. Foster, Gavin L. Bown, Paul R. Gibbs, Samantha J. Sexton, Philip F. Schmidt, Daniela N. Pälike, Heiko Mackensen, Andreas Pancost, Richard D. |
spellingShingle |
Badger, Marcus P.S. Chalk, Thomas B. Foster, Gavin L. Bown, Paul R. Gibbs, Samantha J. Sexton, Philip F. Schmidt, Daniela N. Pälike, Heiko Mackensen, Andreas Pancost, Richard D. Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels |
author_facet |
Badger, Marcus P.S. Chalk, Thomas B. Foster, Gavin L. Bown, Paul R. Gibbs, Samantha J. Sexton, Philip F. Schmidt, Daniela N. Pälike, Heiko Mackensen, Andreas Pancost, Richard D. |
author_sort |
Badger, Marcus P.S. |
title |
Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels |
title_short |
Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels |
title_full |
Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels |
title_fullStr |
Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels |
title_full_unstemmed |
Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels |
title_sort |
insensitivity of alkenone carbon isotopes to atmospheric co2 at low to moderate co2 levels |
publishDate |
2019 |
url |
https://eprints.soton.ac.uk/430074/ https://eprints.soton.ac.uk/430074/1/cp_15_539_2019.pdf |
genre |
ice core |
genre_facet |
ice core |
op_relation |
https://eprints.soton.ac.uk/430074/1/cp_15_539_2019.pdf Badger, Marcus P.S., Chalk, Thomas B., Foster, Gavin L., Bown, Paul R., Gibbs, Samantha J., Sexton, Philip F., Schmidt, Daniela N., Pälike, Heiko, Mackensen, Andreas and Pancost, Richard D. (2019) Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels. Climate of the Past, 15 (2), 539-554. (doi:10.5194/cp-15-539-2019 <http://dx.doi.org/10.5194/cp-15-539-2019>). |
op_rights |
cc_by_4 |
op_doi |
https://doi.org/10.5194/cp-15-539-2019 |
container_title |
Climate of the Past |
container_volume |
15 |
container_issue |
2 |
container_start_page |
539 |
op_container_end_page |
554 |
_version_ |
1775351685157224448 |