Degradation of sterols and terrigenous organic matter in waters of the Mackenzie Shelf, Canadian Arctic
International audience Sterols and their biotic and abiotic degradation products were quantified in suspended particulate matter (SPM) from surface waters in the Mackenzie River mouth to the Beaufort Sea shelf (Canadian Arctic). 24-Ethylcholesterol (sitosterol) and 24-methylcholesterol (campesterol)...
Published in: | Organic Geochemistry |
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Format: | Article in Journal/Newspaper |
Language: | English |
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Online Access: | https://hal.archives-ouvertes.fr/hal-01166011 https://doi.org/10.1016/j.orggeochem.2014.06.002 |
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ftccsdartic:oai:HAL:hal-01166011v1 2023-05-15T15:02:13+02:00 Degradation of sterols and terrigenous organic matter in waters of the Mackenzie Shelf, Canadian Arctic Rontani, Jean-François Charrìère, Bruno SEMPERE, Richard Doxaran, David Vaultier, Frédéric Vonk, Jorien E. Volkman, John K. Institut méditerranéen d'océanologie (MIO) Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN) Aix Marseille Université (AMU) Centre National de la Recherche Scientifique (CNRS) Université de Toulon (UTLN) 2014-06-18 https://hal.archives-ouvertes.fr/hal-01166011 https://doi.org/10.1016/j.orggeochem.2014.06.002 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.orggeochem.2014.06.002 hal-01166011 https://hal.archives-ouvertes.fr/hal-01166011 doi:10.1016/j.orggeochem.2014.06.002 ISSN: 0146-6380 Organic Geochemistry https://hal.archives-ouvertes.fr/hal-01166011 Organic Geochemistry, Elsevier, 2014, 75, pp.61-73. ⟨10.1016/j.orggeochem.2014.06.002⟩ http://www.journals.elsevier.com/organic-geochemistry/ Mackenzie River SPM Sterols Autoxidation Bacterial degradation Terrigenous organic matter Mackenzie shelf Dehydroabietic acid Abiotic and biotic degradation [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/article Journal articles 2014 ftccsdartic https://doi.org/10.1016/j.orggeochem.2014.06.002 2021-10-24T11:54:24Z International audience Sterols and their biotic and abiotic degradation products were quantified in suspended particulate matter (SPM) from surface waters in the Mackenzie River mouth to the Beaufort Sea shelf (Canadian Arctic). 24-Ethylcholesterol (sitosterol) and 24-methylcholesterol (campesterol) appeared to be extensively degraded by bacterial and especially autoxidative degradation in the samples. Degradation was most extensive in some samples from the outer boundaries of the plume, which exhibited much higher sitosterol/campesterol ratio values than previously observed in studies of the Beaufort Sea. The lack of reactivity of specific planktonic sterols such as cholesterol, 24-methylcholesta-5,22E-dien-3β-ol (epi-brassicasterol) and 24-methylenecholesterol and the good correlation between the abundances of sitosterol, campesterol and dehydroabietic acid (DHAA, a biomarker of Pinaceae resin) oxidation products allowed us to attribute the main origin of these two sterols to terrigenous vascular plants. A good correlation was observed between the extent of autoxidation and salinity, suggesting that the free radical oxidation is enhanced via contact with seawater. Laboratory incubation of Mackenzie River SPM in Milli-Q water and seawater confirmed this proposal. To explain the specific induction of autoxidation on vascular plant-derived material, a mechanism involving homolytic cleavage of photochemically produced hydroperoxides resulting from the senescence of higher plants on land is proposed. Cleavage could be catalyzed by redox-active metal ions released from SPM in the mixing zone of riverine water and marine water. The greatest extent of degradation observed at outer boundaries of the plume is attributed to preferential settling of lithic material relative to less dense higher plant debris increasing the proportion of highly degraded vascular plant material in the SPM. The results are important for this ecologically vulnerable region, where destabilization of permafrost by global warming is expected to ... Article in Journal/Newspaper Arctic Beaufort Sea Global warming Mackenzie river Mackenzie Shelf permafrost Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Arctic Mackenzie River Organic Geochemistry 75 61 73 |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
Mackenzie River SPM Sterols Autoxidation Bacterial degradation Terrigenous organic matter Mackenzie shelf Dehydroabietic acid Abiotic and biotic degradation [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
Mackenzie River SPM Sterols Autoxidation Bacterial degradation Terrigenous organic matter Mackenzie shelf Dehydroabietic acid Abiotic and biotic degradation [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Rontani, Jean-François Charrìère, Bruno SEMPERE, Richard Doxaran, David Vaultier, Frédéric Vonk, Jorien E. Volkman, John K. Degradation of sterols and terrigenous organic matter in waters of the Mackenzie Shelf, Canadian Arctic |
topic_facet |
Mackenzie River SPM Sterols Autoxidation Bacterial degradation Terrigenous organic matter Mackenzie shelf Dehydroabietic acid Abiotic and biotic degradation [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
International audience Sterols and their biotic and abiotic degradation products were quantified in suspended particulate matter (SPM) from surface waters in the Mackenzie River mouth to the Beaufort Sea shelf (Canadian Arctic). 24-Ethylcholesterol (sitosterol) and 24-methylcholesterol (campesterol) appeared to be extensively degraded by bacterial and especially autoxidative degradation in the samples. Degradation was most extensive in some samples from the outer boundaries of the plume, which exhibited much higher sitosterol/campesterol ratio values than previously observed in studies of the Beaufort Sea. The lack of reactivity of specific planktonic sterols such as cholesterol, 24-methylcholesta-5,22E-dien-3β-ol (epi-brassicasterol) and 24-methylenecholesterol and the good correlation between the abundances of sitosterol, campesterol and dehydroabietic acid (DHAA, a biomarker of Pinaceae resin) oxidation products allowed us to attribute the main origin of these two sterols to terrigenous vascular plants. A good correlation was observed between the extent of autoxidation and salinity, suggesting that the free radical oxidation is enhanced via contact with seawater. Laboratory incubation of Mackenzie River SPM in Milli-Q water and seawater confirmed this proposal. To explain the specific induction of autoxidation on vascular plant-derived material, a mechanism involving homolytic cleavage of photochemically produced hydroperoxides resulting from the senescence of higher plants on land is proposed. Cleavage could be catalyzed by redox-active metal ions released from SPM in the mixing zone of riverine water and marine water. The greatest extent of degradation observed at outer boundaries of the plume is attributed to preferential settling of lithic material relative to less dense higher plant debris increasing the proportion of highly degraded vascular plant material in the SPM. The results are important for this ecologically vulnerable region, where destabilization of permafrost by global warming is expected to ... |
author2 |
Institut méditerranéen d'océanologie (MIO) Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN) Aix Marseille Université (AMU) Centre National de la Recherche Scientifique (CNRS) Université de Toulon (UTLN) |
format |
Article in Journal/Newspaper |
author |
Rontani, Jean-François Charrìère, Bruno SEMPERE, Richard Doxaran, David Vaultier, Frédéric Vonk, Jorien E. Volkman, John K. |
author_facet |
Rontani, Jean-François Charrìère, Bruno SEMPERE, Richard Doxaran, David Vaultier, Frédéric Vonk, Jorien E. Volkman, John K. |
author_sort |
Rontani, Jean-François |
title |
Degradation of sterols and terrigenous organic matter in waters of the Mackenzie Shelf, Canadian Arctic |
title_short |
Degradation of sterols and terrigenous organic matter in waters of the Mackenzie Shelf, Canadian Arctic |
title_full |
Degradation of sterols and terrigenous organic matter in waters of the Mackenzie Shelf, Canadian Arctic |
title_fullStr |
Degradation of sterols and terrigenous organic matter in waters of the Mackenzie Shelf, Canadian Arctic |
title_full_unstemmed |
Degradation of sterols and terrigenous organic matter in waters of the Mackenzie Shelf, Canadian Arctic |
title_sort |
degradation of sterols and terrigenous organic matter in waters of the mackenzie shelf, canadian arctic |
publisher |
HAL CCSD |
publishDate |
2014 |
url |
https://hal.archives-ouvertes.fr/hal-01166011 https://doi.org/10.1016/j.orggeochem.2014.06.002 |
geographic |
Arctic Mackenzie River |
geographic_facet |
Arctic Mackenzie River |
genre |
Arctic Beaufort Sea Global warming Mackenzie river Mackenzie Shelf permafrost |
genre_facet |
Arctic Beaufort Sea Global warming Mackenzie river Mackenzie Shelf permafrost |
op_source |
ISSN: 0146-6380 Organic Geochemistry https://hal.archives-ouvertes.fr/hal-01166011 Organic Geochemistry, Elsevier, 2014, 75, pp.61-73. ⟨10.1016/j.orggeochem.2014.06.002⟩ http://www.journals.elsevier.com/organic-geochemistry/ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.orggeochem.2014.06.002 hal-01166011 https://hal.archives-ouvertes.fr/hal-01166011 doi:10.1016/j.orggeochem.2014.06.002 |
op_doi |
https://doi.org/10.1016/j.orggeochem.2014.06.002 |
container_title |
Organic Geochemistry |
container_volume |
75 |
container_start_page |
61 |
op_container_end_page |
73 |
_version_ |
1766334196703297536 |