Abiotic degradation of highly branched isoprenoid alkenes and other lipids in the water column off East Antarctica
© 2019 In some previous studies, the ratio between a di-unsaturated highly branched isoprenoid (HBI) lipid termed IPSO 25 and a structurally related tri-unsaturated counterpart (HBI III) (viz. IPSO 25 /HBI III) has been used as a proxy measure of variable sea ice cover in the Antarctic owing to thei...
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Online Access: | http://hdl.handle.net/10026.1/13533 https://doi.org/10.1016/j.marchem.2019.02.004 |
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ftunivplympearl:oai:pearl.plymouth.ac.uk:10026.1/13533 2023-05-15T13:56:05+02:00 Abiotic degradation of highly branched isoprenoid alkenes and other lipids in the water column off East Antarctica Rontani, JF Smik, L Belt, ST Vaultier, F Armbrecht, L Leventer, A Armand, LK 2019-03-20 34 - 47 http://hdl.handle.net/10026.1/13533 https://doi.org/10.1016/j.marchem.2019.02.004 en eng Elsevier ISSN:0304-4203 0304-4203 http://hdl.handle.net/10026.1/13533 doi:10.1016/j.marchem.2019.02.004 2020-08-14 Not known Journal Article 2019 ftunivplympearl https://doi.org/10.1016/j.marchem.2019.02.004 2021-03-09T18:36:32Z © 2019 In some previous studies, the ratio between a di-unsaturated highly branched isoprenoid (HBI) lipid termed IPSO 25 and a structurally related tri-unsaturated counterpart (HBI III) (viz. IPSO 25 /HBI III) has been used as a proxy measure of variable sea ice cover in the Antarctic owing to their production by certain sea ice algae and open water diatoms, respectively. To investigate this further, we quantified selected lipids and their photo- and autoxidation products in samples of suspended particulate matter (SPM) collected at different water depths in the polynya region west of the Dalton Iceberg Tongue (East Antarctica). The results obtained confirm the high efficiency of photo- and autoxidation processes in diatoms from the region. The systematic increase of the ratio IPSO 25 /HBI III with water depth in the current samples appeared to be dependent on the sampling site and was due to both (i) a relatively higher contribution of ice algae to the deeper samples resulting from their increased aggregation and therefore higher sinking rate, or (ii) a stronger abiotic degradation of HBI III during settling through the water column. Analyses of samples taken from the water-sediment interface and some underlying near-surface sediments revealed a further increase of the ratio IPSO 25 /HBI III, indicative of further differential oxidation of the more unsaturated HBI. Unfortunately, specific oxidation products of HBI III could not be detected in the strongly oxidized SPM and sediment samples, likely due to their lability towards further oxidation. In contrast, oxidation products of HBI III were detected in weakly oxidized samples of phytoplanktonic cells collected from Commonwealth Bay (also East Antarctica), thus providing more direct evidence for the involvement of photo- and/or autoxidation of HBI III in the region. This oxidative alteration of the ratio IPSO 25 /HBI III between their source and sedimentary environments might need to be considered more carefully when using this parameter for palaeo sea ice reconstruction purposes in the Antarctic. Article in Journal/Newspaper Antarc* Antarctic Antarctica East Antarctica ice algae Iceberg* Sea ice PEARL (Plymouth Electronic Archiv & ResearchLibrary, Plymouth University) Antarctic The Antarctic East Antarctica Commonwealth Bay ENVELOPE(142.500,142.500,-67.000,-67.000) Dalton Iceberg Tongue ENVELOPE(121.500,121.500,-66.250,-66.250) Marine Chemistry 210 34 47 |
institution |
Open Polar |
collection |
PEARL (Plymouth Electronic Archiv & ResearchLibrary, Plymouth University) |
op_collection_id |
ftunivplympearl |
language |
English |
description |
© 2019 In some previous studies, the ratio between a di-unsaturated highly branched isoprenoid (HBI) lipid termed IPSO 25 and a structurally related tri-unsaturated counterpart (HBI III) (viz. IPSO 25 /HBI III) has been used as a proxy measure of variable sea ice cover in the Antarctic owing to their production by certain sea ice algae and open water diatoms, respectively. To investigate this further, we quantified selected lipids and their photo- and autoxidation products in samples of suspended particulate matter (SPM) collected at different water depths in the polynya region west of the Dalton Iceberg Tongue (East Antarctica). The results obtained confirm the high efficiency of photo- and autoxidation processes in diatoms from the region. The systematic increase of the ratio IPSO 25 /HBI III with water depth in the current samples appeared to be dependent on the sampling site and was due to both (i) a relatively higher contribution of ice algae to the deeper samples resulting from their increased aggregation and therefore higher sinking rate, or (ii) a stronger abiotic degradation of HBI III during settling through the water column. Analyses of samples taken from the water-sediment interface and some underlying near-surface sediments revealed a further increase of the ratio IPSO 25 /HBI III, indicative of further differential oxidation of the more unsaturated HBI. Unfortunately, specific oxidation products of HBI III could not be detected in the strongly oxidized SPM and sediment samples, likely due to their lability towards further oxidation. In contrast, oxidation products of HBI III were detected in weakly oxidized samples of phytoplanktonic cells collected from Commonwealth Bay (also East Antarctica), thus providing more direct evidence for the involvement of photo- and/or autoxidation of HBI III in the region. This oxidative alteration of the ratio IPSO 25 /HBI III between their source and sedimentary environments might need to be considered more carefully when using this parameter for palaeo sea ice reconstruction purposes in the Antarctic. |
format |
Article in Journal/Newspaper |
author |
Rontani, JF Smik, L Belt, ST Vaultier, F Armbrecht, L Leventer, A Armand, LK |
spellingShingle |
Rontani, JF Smik, L Belt, ST Vaultier, F Armbrecht, L Leventer, A Armand, LK Abiotic degradation of highly branched isoprenoid alkenes and other lipids in the water column off East Antarctica |
author_facet |
Rontani, JF Smik, L Belt, ST Vaultier, F Armbrecht, L Leventer, A Armand, LK |
author_sort |
Rontani, JF |
title |
Abiotic degradation of highly branched isoprenoid alkenes and other lipids in the water column off East Antarctica |
title_short |
Abiotic degradation of highly branched isoprenoid alkenes and other lipids in the water column off East Antarctica |
title_full |
Abiotic degradation of highly branched isoprenoid alkenes and other lipids in the water column off East Antarctica |
title_fullStr |
Abiotic degradation of highly branched isoprenoid alkenes and other lipids in the water column off East Antarctica |
title_full_unstemmed |
Abiotic degradation of highly branched isoprenoid alkenes and other lipids in the water column off East Antarctica |
title_sort |
abiotic degradation of highly branched isoprenoid alkenes and other lipids in the water column off east antarctica |
publisher |
Elsevier |
publishDate |
2019 |
url |
http://hdl.handle.net/10026.1/13533 https://doi.org/10.1016/j.marchem.2019.02.004 |
long_lat |
ENVELOPE(142.500,142.500,-67.000,-67.000) ENVELOPE(121.500,121.500,-66.250,-66.250) |
geographic |
Antarctic The Antarctic East Antarctica Commonwealth Bay Dalton Iceberg Tongue |
geographic_facet |
Antarctic The Antarctic East Antarctica Commonwealth Bay Dalton Iceberg Tongue |
genre |
Antarc* Antarctic Antarctica East Antarctica ice algae Iceberg* Sea ice |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica ice algae Iceberg* Sea ice |
op_relation |
ISSN:0304-4203 0304-4203 http://hdl.handle.net/10026.1/13533 doi:10.1016/j.marchem.2019.02.004 |
op_rights |
2020-08-14 Not known |
op_doi |
https://doi.org/10.1016/j.marchem.2019.02.004 |
container_title |
Marine Chemistry |
container_volume |
210 |
container_start_page |
34 |
op_container_end_page |
47 |
_version_ |
1766263300059824128 |