Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach
For the next decades significant climatic changes should occur in the Arctic zone. The expected destabilisation of permafrost and its consequences for hydrology and plant cover should increase the input of terrigenous carbon to coastal seas. Consequently, the relative importance of the fluxes of ter...
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Copernicus Publications
2012
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00024471 2023-05-15T15:01:51+02:00 Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach Rontani, J.-F. Charriere, B. Petit, M. Vaultier, F. Heipieper, H. J. Link, H. Chaillou, G. Sempéré, R. 2012-09 electronic https://doi.org/10.5194/bg-9-3513-2012 https://noa.gwlb.de/receive/cop_mods_00024471 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00024426/bg-9-3513-2012.pdf https://bg.copernicus.org/articles/9/3513/2012/bg-9-3513-2012.pdf eng eng Copernicus Publications Biogeosciences -- http://www.bibliothek.uni-regensburg.de/ezeit/?2158181 -- http://www.copernicus.org/EGU/bg/bg.html -- 1726-4189 https://doi.org/10.5194/bg-9-3513-2012 https://noa.gwlb.de/receive/cop_mods_00024471 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00024426/bg-9-3513-2012.pdf https://bg.copernicus.org/articles/9/3513/2012/bg-9-3513-2012.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2012 ftnonlinearchiv https://doi.org/10.5194/bg-9-3513-2012 2022-02-08T22:50:10Z For the next decades significant climatic changes should occur in the Arctic zone. The expected destabilisation of permafrost and its consequences for hydrology and plant cover should increase the input of terrigenous carbon to coastal seas. Consequently, the relative importance of the fluxes of terrestrial and marine organic carbon to the seafloor will likely change, strongly impacting the preservation of organic carbon in Arctic marine sediments. Here, we investigated the lipid content of surface sediments collected on the Mackenzie basin in the Beaufort Sea. Particular attention was given to biotic and abiotic degradation products of sterols and monounsaturated fatty acids. By using sitosterol and campesterol degradation products as tracers of the degradation of terrestrial higher plant inputs and brassicasterol degradation products as tracers of degradation of phytoplanktonic organisms, it could be observed that autoxidation, photooxidation and biodegradation processes act much more intensively on higher plant debris than on phytoplanktonic organisms. Examination of oxidation products of monounsaturated fatty acids showed that photo- and autoxidation processes act more intensively on bacteria than on phytodetritus. Enhanced damages induced by singlet oxygen (transferred from senescent phytoplanktonic cells) in bacteria were attributed to the lack of an adapted antioxidant system in these microorganisms. The strong oxidative stress observed in the sampled sediments resulted in the production of significant amounts of epoxy acids and unusually high proportions of monounsaturated fatty acids with a trans double bond. The formation of epoxy acids was attributed to peroxygenases (enzymes playing a protective role against the deleterious effects of fatty acid hydroperoxides in vivo), while cis/trans isomerisation was probably induced by thiyl radicals produced during the reaction of thiols with hydroperoxides. Our results confirm the important role played by abiotic oxidative processes in the degradation of marine bacteria and do not support the generally expected refractory character of terrigenous material deposited in deltaic systems. Article in Journal/Newspaper Arctic Beaufort Sea Mackenzie Basin permafrost Niedersächsisches Online-Archiv NOA Arctic Biogeosciences 9 9 3513 3530 |
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Niedersächsisches Online-Archiv NOA |
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English |
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article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Rontani, J.-F. Charriere, B. Petit, M. Vaultier, F. Heipieper, H. J. Link, H. Chaillou, G. Sempéré, R. Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach |
topic_facet |
article Verlagsveröffentlichung |
description |
For the next decades significant climatic changes should occur in the Arctic zone. The expected destabilisation of permafrost and its consequences for hydrology and plant cover should increase the input of terrigenous carbon to coastal seas. Consequently, the relative importance of the fluxes of terrestrial and marine organic carbon to the seafloor will likely change, strongly impacting the preservation of organic carbon in Arctic marine sediments. Here, we investigated the lipid content of surface sediments collected on the Mackenzie basin in the Beaufort Sea. Particular attention was given to biotic and abiotic degradation products of sterols and monounsaturated fatty acids. By using sitosterol and campesterol degradation products as tracers of the degradation of terrestrial higher plant inputs and brassicasterol degradation products as tracers of degradation of phytoplanktonic organisms, it could be observed that autoxidation, photooxidation and biodegradation processes act much more intensively on higher plant debris than on phytoplanktonic organisms. Examination of oxidation products of monounsaturated fatty acids showed that photo- and autoxidation processes act more intensively on bacteria than on phytodetritus. Enhanced damages induced by singlet oxygen (transferred from senescent phytoplanktonic cells) in bacteria were attributed to the lack of an adapted antioxidant system in these microorganisms. The strong oxidative stress observed in the sampled sediments resulted in the production of significant amounts of epoxy acids and unusually high proportions of monounsaturated fatty acids with a trans double bond. The formation of epoxy acids was attributed to peroxygenases (enzymes playing a protective role against the deleterious effects of fatty acid hydroperoxides in vivo), while cis/trans isomerisation was probably induced by thiyl radicals produced during the reaction of thiols with hydroperoxides. Our results confirm the important role played by abiotic oxidative processes in the degradation of marine bacteria and do not support the generally expected refractory character of terrigenous material deposited in deltaic systems. |
format |
Article in Journal/Newspaper |
author |
Rontani, J.-F. Charriere, B. Petit, M. Vaultier, F. Heipieper, H. J. Link, H. Chaillou, G. Sempéré, R. |
author_facet |
Rontani, J.-F. Charriere, B. Petit, M. Vaultier, F. Heipieper, H. J. Link, H. Chaillou, G. Sempéré, R. |
author_sort |
Rontani, J.-F. |
title |
Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach |
title_short |
Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach |
title_full |
Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach |
title_fullStr |
Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach |
title_full_unstemmed |
Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach |
title_sort |
degradation state of organic matter in surface sediments from the southern beaufort sea: a lipid approach |
publisher |
Copernicus Publications |
publishDate |
2012 |
url |
https://doi.org/10.5194/bg-9-3513-2012 https://noa.gwlb.de/receive/cop_mods_00024471 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00024426/bg-9-3513-2012.pdf https://bg.copernicus.org/articles/9/3513/2012/bg-9-3513-2012.pdf |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Beaufort Sea Mackenzie Basin permafrost |
genre_facet |
Arctic Beaufort Sea Mackenzie Basin permafrost |
op_relation |
Biogeosciences -- http://www.bibliothek.uni-regensburg.de/ezeit/?2158181 -- http://www.copernicus.org/EGU/bg/bg.html -- 1726-4189 https://doi.org/10.5194/bg-9-3513-2012 https://noa.gwlb.de/receive/cop_mods_00024471 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00024426/bg-9-3513-2012.pdf https://bg.copernicus.org/articles/9/3513/2012/bg-9-3513-2012.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/bg-9-3513-2012 |
container_title |
Biogeosciences |
container_volume |
9 |
container_issue |
9 |
container_start_page |
3513 |
op_container_end_page |
3530 |
_version_ |
1766333853509615616 |