Impact of non-thermal variables on hydroxylated GDGT distributions around Iceland
Archaeal isoprenoid glycerol dibiphytanyl glycerol tetraethers (GDGTs) preserved in sediments are popular tools for the reconstruction of past temperature in the global ocean. Whereas the most common GDGTs have been well studied through environmental and culture studies, their hydroxylated version (...
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Online Access: | http://dx.doi.org/10.3389/feart.2024.1430441 https://www.frontiersin.org/articles/10.3389/feart.2024.1430441/full |
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crfrontiers:10.3389/feart.2024.1430441 2024-09-15T18:13:19+00:00 Impact of non-thermal variables on hydroxylated GDGT distributions around Iceland Harning, David J. Sepúlveda, Julio 2024 http://dx.doi.org/10.3389/feart.2024.1430441 https://www.frontiersin.org/articles/10.3389/feart.2024.1430441/full unknown Frontiers Media SA https://creativecommons.org/licenses/by/4.0/ Frontiers in Earth Science volume 12 ISSN 2296-6463 journal-article 2024 crfrontiers https://doi.org/10.3389/feart.2024.1430441 2024-09-03T04:04:19Z Archaeal isoprenoid glycerol dibiphytanyl glycerol tetraethers (GDGTs) preserved in sediments are popular tools for the reconstruction of past temperature in the global ocean. Whereas the most common GDGTs have been well studied through environmental and culture studies, their hydroxylated version (OH-GDGTs) is just emerging as a new proxy. Some empirical evidence suggests that the distribution of OH-GDGTs may capture sea surface temperature variability. However, the effects of additional environmental factors on OH-GDGT distributions have not been rigorously tested, and evidence suggests that salinity, sea ice, seasonality, terrestrial input, and water depth may be additional factors in some settings. In this study, we analyzed the distribution of OH-GDGTs in modern and Holocene marine sediment from the North Iceland Shelf. By statistically comparing the biomarker datasets against a collection of modern instrumental and paleoceanographic records, we separated which environmental variables may be controlling OH-GDGT-derived proxies around Iceland. In contrast to prevailing theory, we found that nitrate concentrations and water-column stratification are best correlated to OH-GDGT distributions, and not temperature. These results hold important implications for the application of OH-GDGT proxies in high-latitude oceans, particularly in highly stratified locations, as well as for future studies on the biological sources and functionality of these lipids. Given the current complexity of proxy interpretation, we urge caution in the current application of OH-GDGTs as a tool in paleotemperature reconstructions. Article in Journal/Newspaper Iceland Sea ice Frontiers (Publisher) Frontiers in Earth Science 12 |
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Archaeal isoprenoid glycerol dibiphytanyl glycerol tetraethers (GDGTs) preserved in sediments are popular tools for the reconstruction of past temperature in the global ocean. Whereas the most common GDGTs have been well studied through environmental and culture studies, their hydroxylated version (OH-GDGTs) is just emerging as a new proxy. Some empirical evidence suggests that the distribution of OH-GDGTs may capture sea surface temperature variability. However, the effects of additional environmental factors on OH-GDGT distributions have not been rigorously tested, and evidence suggests that salinity, sea ice, seasonality, terrestrial input, and water depth may be additional factors in some settings. In this study, we analyzed the distribution of OH-GDGTs in modern and Holocene marine sediment from the North Iceland Shelf. By statistically comparing the biomarker datasets against a collection of modern instrumental and paleoceanographic records, we separated which environmental variables may be controlling OH-GDGT-derived proxies around Iceland. In contrast to prevailing theory, we found that nitrate concentrations and water-column stratification are best correlated to OH-GDGT distributions, and not temperature. These results hold important implications for the application of OH-GDGT proxies in high-latitude oceans, particularly in highly stratified locations, as well as for future studies on the biological sources and functionality of these lipids. Given the current complexity of proxy interpretation, we urge caution in the current application of OH-GDGTs as a tool in paleotemperature reconstructions. |
format |
Article in Journal/Newspaper |
author |
Harning, David J. Sepúlveda, Julio |
spellingShingle |
Harning, David J. Sepúlveda, Julio Impact of non-thermal variables on hydroxylated GDGT distributions around Iceland |
author_facet |
Harning, David J. Sepúlveda, Julio |
author_sort |
Harning, David J. |
title |
Impact of non-thermal variables on hydroxylated GDGT distributions around Iceland |
title_short |
Impact of non-thermal variables on hydroxylated GDGT distributions around Iceland |
title_full |
Impact of non-thermal variables on hydroxylated GDGT distributions around Iceland |
title_fullStr |
Impact of non-thermal variables on hydroxylated GDGT distributions around Iceland |
title_full_unstemmed |
Impact of non-thermal variables on hydroxylated GDGT distributions around Iceland |
title_sort |
impact of non-thermal variables on hydroxylated gdgt distributions around iceland |
publisher |
Frontiers Media SA |
publishDate |
2024 |
url |
http://dx.doi.org/10.3389/feart.2024.1430441 https://www.frontiersin.org/articles/10.3389/feart.2024.1430441/full |
genre |
Iceland Sea ice |
genre_facet |
Iceland Sea ice |
op_source |
Frontiers in Earth Science volume 12 ISSN 2296-6463 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3389/feart.2024.1430441 |
container_title |
Frontiers in Earth Science |
container_volume |
12 |
_version_ |
1810451046519013376 |