Development of source specific diatom lipids biomarkers as Antarctic Sea Ice proxies

C25 highly branched isoprenoid (HBI) are lipid biomarkers biosynthesised by a relatively small number of diatomgenera, but are, nonetheless, common constituents of global marine sediments. The occurrence and variableabundance of certain C25 highly branched isoprenoid (HBI) biomarkers in Antarctic ma...

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Main Authors: Smik, L, Belt, ST, Brown, TA, Lieser, JL, Armand, LK, Leventer, A, Allen, CS
Format: Conference Object
Language:English
Published: Copernicus GmbH 2016
Subjects:
Online Access:http://ecite.utas.edu.au/110165
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record_format openpolar
spelling ftunivtasecite:oai:ecite.utas.edu.au:110165 2023-05-15T14:03:26+02:00 Development of source specific diatom lipids biomarkers as Antarctic Sea Ice proxies Smik, L Belt, ST Brown, TA Lieser, JL Armand, LK Leventer, A Allen, CS 2016 application/pdf http://ecite.utas.edu.au/110165 en eng Copernicus GmbH http://ecite.utas.edu.au/110165/1/EGU2016-693.pdf Smik, L and Belt, ST and Brown, TA and Lieser, JL and Armand, LK and Leventer, A and Allen, CS, Development of source specific diatom lipids biomarkers as Antarctic Sea Ice proxies, Geophysical Research Abstracts, 17-22 May 2016, Vienna, Austria, pp. 693. ISSN 1607-7962 (2016) [Conference Extract] http://ecite.utas.edu.au/110165 Earth Sciences Physical Geography and Environmental Geoscience Physical Geography and Environmental Geoscience not elsewhere classified Conference Extract NonPeerReviewed 2016 ftunivtasecite 2019-12-13T22:10:45Z C25 highly branched isoprenoid (HBI) are lipid biomarkers biosynthesised by a relatively small number of diatomgenera, but are, nonetheless, common constituents of global marine sediments. The occurrence and variableabundance of certain C25 highly branched isoprenoid (HBI) biomarkers in Antarctic marine sediments haspreviously been proposed as a proxy measure of paleo sea-ice extent in the Southern Ocean and a small numberof paleo sea-ice reconstructions based on the variable abundances of these HBIs have appeared in recent years.However, the development of HBIs as proxies for Antarctic sea ice is much less advanced than that for IP25(another HBI) in the Arctic and has been based on relatively small number of analyses in sea ice, water columnand sediment samples. To provide further insights into the use of these HBIs as proxies for Antarctic sea ice, we here describe anassessment of their distributions in surface water, surface sediment and sea ice samples collected from a numberof Antarctic locations experiencing contrasting sea ice conditions in recent years. Our study shows that distributions of a di-unsaturated HBI (diene II) and tri-unsaturated HBI (triene III) insurface water samples were found to be extremely sensitive to the local sea-ice conditions, with diene II detectedfor sampling sites that experienced seasonal sea ice and highest concentrations found in coastal locations withlonger-lasting ice cover and a recurrent polynya. In contrast, triene III was observed in all of the samples analysed,but with highest concentrations within the region of the retreating sea ice edge, an observation consistent withsignificant environmental control over the biosynthesis of diene II and triene III by sea ice diatoms and open waterphytoplankton, respectively. However, additional local factors, such as those associated with polynya formation,may also exert some control over the distribution of triene III and the relative concentrations of diene II andtriene III, in particular. This may have important implications for the use of these biomarkers for paleo sea icereconstructions. Sedimentary distribution showed significant variation in abundances of diene II and triene III between differentregions of Antarctica, but also on a more local scale, potentially reflecting a high degree of sensitivity towardsindividual sea ice dynamics that favour the individual species responsible for their biosynthesis. However, highestconcentrations of diene II were generally observed in near coastal locations, consistent with the identification ofelevated abundances of this HBI in first year or land fast ice in these settings. The identification of the sea icediatom source of diene II will likely be significant in interpretations of the occurrence of this biomarker in paleosea ice records. Conference Object Antarc* Antarctic Antarctica Arctic Sea ice Southern Ocean eCite UTAS (University of Tasmania) Antarctic Arctic Southern Ocean
institution Open Polar
collection eCite UTAS (University of Tasmania)
op_collection_id ftunivtasecite
language English
topic Earth Sciences
Physical Geography and Environmental Geoscience
Physical Geography and Environmental Geoscience not elsewhere classified
spellingShingle Earth Sciences
Physical Geography and Environmental Geoscience
Physical Geography and Environmental Geoscience not elsewhere classified
Smik, L
Belt, ST
Brown, TA
Lieser, JL
Armand, LK
Leventer, A
Allen, CS
Development of source specific diatom lipids biomarkers as Antarctic Sea Ice proxies
topic_facet Earth Sciences
Physical Geography and Environmental Geoscience
Physical Geography and Environmental Geoscience not elsewhere classified
description C25 highly branched isoprenoid (HBI) are lipid biomarkers biosynthesised by a relatively small number of diatomgenera, but are, nonetheless, common constituents of global marine sediments. The occurrence and variableabundance of certain C25 highly branched isoprenoid (HBI) biomarkers in Antarctic marine sediments haspreviously been proposed as a proxy measure of paleo sea-ice extent in the Southern Ocean and a small numberof paleo sea-ice reconstructions based on the variable abundances of these HBIs have appeared in recent years.However, the development of HBIs as proxies for Antarctic sea ice is much less advanced than that for IP25(another HBI) in the Arctic and has been based on relatively small number of analyses in sea ice, water columnand sediment samples. To provide further insights into the use of these HBIs as proxies for Antarctic sea ice, we here describe anassessment of their distributions in surface water, surface sediment and sea ice samples collected from a numberof Antarctic locations experiencing contrasting sea ice conditions in recent years. Our study shows that distributions of a di-unsaturated HBI (diene II) and tri-unsaturated HBI (triene III) insurface water samples were found to be extremely sensitive to the local sea-ice conditions, with diene II detectedfor sampling sites that experienced seasonal sea ice and highest concentrations found in coastal locations withlonger-lasting ice cover and a recurrent polynya. In contrast, triene III was observed in all of the samples analysed,but with highest concentrations within the region of the retreating sea ice edge, an observation consistent withsignificant environmental control over the biosynthesis of diene II and triene III by sea ice diatoms and open waterphytoplankton, respectively. However, additional local factors, such as those associated with polynya formation,may also exert some control over the distribution of triene III and the relative concentrations of diene II andtriene III, in particular. This may have important implications for the use of these biomarkers for paleo sea icereconstructions. Sedimentary distribution showed significant variation in abundances of diene II and triene III between differentregions of Antarctica, but also on a more local scale, potentially reflecting a high degree of sensitivity towardsindividual sea ice dynamics that favour the individual species responsible for their biosynthesis. However, highestconcentrations of diene II were generally observed in near coastal locations, consistent with the identification ofelevated abundances of this HBI in first year or land fast ice in these settings. The identification of the sea icediatom source of diene II will likely be significant in interpretations of the occurrence of this biomarker in paleosea ice records.
format Conference Object
author Smik, L
Belt, ST
Brown, TA
Lieser, JL
Armand, LK
Leventer, A
Allen, CS
author_facet Smik, L
Belt, ST
Brown, TA
Lieser, JL
Armand, LK
Leventer, A
Allen, CS
author_sort Smik, L
title Development of source specific diatom lipids biomarkers as Antarctic Sea Ice proxies
title_short Development of source specific diatom lipids biomarkers as Antarctic Sea Ice proxies
title_full Development of source specific diatom lipids biomarkers as Antarctic Sea Ice proxies
title_fullStr Development of source specific diatom lipids biomarkers as Antarctic Sea Ice proxies
title_full_unstemmed Development of source specific diatom lipids biomarkers as Antarctic Sea Ice proxies
title_sort development of source specific diatom lipids biomarkers as antarctic sea ice proxies
publisher Copernicus GmbH
publishDate 2016
url http://ecite.utas.edu.au/110165
geographic Antarctic
Arctic
Southern Ocean
geographic_facet Antarctic
Arctic
Southern Ocean
genre Antarc*
Antarctic
Antarctica
Arctic
Sea ice
Southern Ocean
genre_facet Antarc*
Antarctic
Antarctica
Arctic
Sea ice
Southern Ocean
op_relation http://ecite.utas.edu.au/110165/1/EGU2016-693.pdf
Smik, L and Belt, ST and Brown, TA and Lieser, JL and Armand, LK and Leventer, A and Allen, CS, Development of source specific diatom lipids biomarkers as Antarctic Sea Ice proxies, Geophysical Research Abstracts, 17-22 May 2016, Vienna, Austria, pp. 693. ISSN 1607-7962 (2016) [Conference Extract]
http://ecite.utas.edu.au/110165
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