Upper ocean temperature characteristics in the subantarctic Southeast Pacific based on biomarker reconstructions
Alkenones and Glycerol Dialkyl Glycerol Tetraether lipids (GDGT) as remnants of living organisms are widely used biomarkers for determining past oceans’ water temperatures. The organisms these proxy carriers stem from, are influenced by a number of environmental parameters, such as water depth, nutr...
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Copernicus Publications
2022
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Online Access: | https://doi.org/10.5194/egusphere-2022-1456 https://noa.gwlb.de/receive/cop_mods_00064081 https://egusphere.copernicus.org/preprints/egusphere-2022-1456/egusphere-2022-1456.pdf |
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00064081 2023-05-15T16:02:31+02:00 Upper ocean temperature characteristics in the subantarctic Southeast Pacific based on biomarker reconstructions Hagemann, Julia Rieke Lembke-Jene, Lester Lamy, Frank Vorrath, Maria-Elena Kaiser, Jérôme Müller, Juliane Arz, Helge W. Hefter, Jens Jaeschke, Andrea Ruggieri, Nicoletta Tiedemann, Ralf 2022-12 electronic https://doi.org/10.5194/egusphere-2022-1456 https://noa.gwlb.de/receive/cop_mods_00064081 https://egusphere.copernicus.org/preprints/egusphere-2022-1456/egusphere-2022-1456.pdf eng eng Copernicus Publications https://doi.org/10.5194/egusphere-2022-1456 https://noa.gwlb.de/receive/cop_mods_00064081 https://egusphere.copernicus.org/preprints/egusphere-2022-1456/egusphere-2022-1456.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/restrictedAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2022 ftnonlinearchiv https://doi.org/10.5194/egusphere-2022-1456 2022-12-26T00:12:59Z Alkenones and Glycerol Dialkyl Glycerol Tetraether lipids (GDGT) as remnants of living organisms are widely used biomarkers for determining past oceans’ water temperatures. The organisms these proxy carriers stem from, are influenced by a number of environmental parameters, such as water depth, nutrient availability, light conditions or seasonality, which all may significantly bias the calibration to ambient water temperatures. Reliable temperature determinations remain thus challenging, especially in higher latitudes and for under-sampled regions. We analyzed 33 sediment surface samples from the Southern Chilean continental margin and the Drake Passage for alkenones and GDGTs and compared the results with gridded instrumental reference data from the World Ocean Atlas 2005 (WOA05), as well as previously published data from an extended study area covering the Central and Western South Pacific towards the New Zealand continental margin. We show that for alkenone-derived SSTs, the widely-used global core-top calibration of Müller et al. (1998) yields the smallest residuals, whereas the calibration of Sikes et al. (1997), adapted to higher latitudes and supposed to show summer SSTs, overestimates modern WOA05-based (summer and annual mean) SSTs. Our alkenone SSTs show a slight seasonal shift of ~1 °C at the Southern Chilean Margin and up to ~2 °C in the Drake Passage towards austral summer SSTs, whereas samples in the Central South Pacific reflect an annual mean signal. We show that for GDGT-based temperatures, a more complex pattern emerges. In areas north of the Subantarctic Front (SAF) the subsurface calibration of Kim et al. (2012a) best reflects temperatures from the WOA05, largely within the margin error of ±2.2 °C. Temperatures south of the SAF instead are significantly overestimated by up to 14 °C, irrespective of the applied calibration. Based on a qualitative assessment of the GDGT [2] / [3]-ratios, which likely indicate water depth of origin, our samples reflect a subsurface (0 to 200 m water depth) ... Article in Journal/Newspaper Drake Passage Niedersächsisches Online-Archiv NOA Austral Drake Passage New Zealand Pacific |
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Open Polar |
collection |
Niedersächsisches Online-Archiv NOA |
op_collection_id |
ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Hagemann, Julia Rieke Lembke-Jene, Lester Lamy, Frank Vorrath, Maria-Elena Kaiser, Jérôme Müller, Juliane Arz, Helge W. Hefter, Jens Jaeschke, Andrea Ruggieri, Nicoletta Tiedemann, Ralf Upper ocean temperature characteristics in the subantarctic Southeast Pacific based on biomarker reconstructions |
topic_facet |
article Verlagsveröffentlichung |
description |
Alkenones and Glycerol Dialkyl Glycerol Tetraether lipids (GDGT) as remnants of living organisms are widely used biomarkers for determining past oceans’ water temperatures. The organisms these proxy carriers stem from, are influenced by a number of environmental parameters, such as water depth, nutrient availability, light conditions or seasonality, which all may significantly bias the calibration to ambient water temperatures. Reliable temperature determinations remain thus challenging, especially in higher latitudes and for under-sampled regions. We analyzed 33 sediment surface samples from the Southern Chilean continental margin and the Drake Passage for alkenones and GDGTs and compared the results with gridded instrumental reference data from the World Ocean Atlas 2005 (WOA05), as well as previously published data from an extended study area covering the Central and Western South Pacific towards the New Zealand continental margin. We show that for alkenone-derived SSTs, the widely-used global core-top calibration of Müller et al. (1998) yields the smallest residuals, whereas the calibration of Sikes et al. (1997), adapted to higher latitudes and supposed to show summer SSTs, overestimates modern WOA05-based (summer and annual mean) SSTs. Our alkenone SSTs show a slight seasonal shift of ~1 °C at the Southern Chilean Margin and up to ~2 °C in the Drake Passage towards austral summer SSTs, whereas samples in the Central South Pacific reflect an annual mean signal. We show that for GDGT-based temperatures, a more complex pattern emerges. In areas north of the Subantarctic Front (SAF) the subsurface calibration of Kim et al. (2012a) best reflects temperatures from the WOA05, largely within the margin error of ±2.2 °C. Temperatures south of the SAF instead are significantly overestimated by up to 14 °C, irrespective of the applied calibration. Based on a qualitative assessment of the GDGT [2] / [3]-ratios, which likely indicate water depth of origin, our samples reflect a subsurface (0 to 200 m water depth) ... |
format |
Article in Journal/Newspaper |
author |
Hagemann, Julia Rieke Lembke-Jene, Lester Lamy, Frank Vorrath, Maria-Elena Kaiser, Jérôme Müller, Juliane Arz, Helge W. Hefter, Jens Jaeschke, Andrea Ruggieri, Nicoletta Tiedemann, Ralf |
author_facet |
Hagemann, Julia Rieke Lembke-Jene, Lester Lamy, Frank Vorrath, Maria-Elena Kaiser, Jérôme Müller, Juliane Arz, Helge W. Hefter, Jens Jaeschke, Andrea Ruggieri, Nicoletta Tiedemann, Ralf |
author_sort |
Hagemann, Julia Rieke |
title |
Upper ocean temperature characteristics in the subantarctic Southeast Pacific based on biomarker reconstructions |
title_short |
Upper ocean temperature characteristics in the subantarctic Southeast Pacific based on biomarker reconstructions |
title_full |
Upper ocean temperature characteristics in the subantarctic Southeast Pacific based on biomarker reconstructions |
title_fullStr |
Upper ocean temperature characteristics in the subantarctic Southeast Pacific based on biomarker reconstructions |
title_full_unstemmed |
Upper ocean temperature characteristics in the subantarctic Southeast Pacific based on biomarker reconstructions |
title_sort |
upper ocean temperature characteristics in the subantarctic southeast pacific based on biomarker reconstructions |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/egusphere-2022-1456 https://noa.gwlb.de/receive/cop_mods_00064081 https://egusphere.copernicus.org/preprints/egusphere-2022-1456/egusphere-2022-1456.pdf |
geographic |
Austral Drake Passage New Zealand Pacific |
geographic_facet |
Austral Drake Passage New Zealand Pacific |
genre |
Drake Passage |
genre_facet |
Drake Passage |
op_relation |
https://doi.org/10.5194/egusphere-2022-1456 https://noa.gwlb.de/receive/cop_mods_00064081 https://egusphere.copernicus.org/preprints/egusphere-2022-1456/egusphere-2022-1456.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/restrictedAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/egusphere-2022-1456 |
_version_ |
1766398177132412928 |