Molecular-multiproxy assessment of land-derived organic matter degradation over extensive scales of the East Siberian Arctic Shelf seas

doi:10.1029/2022GB007428

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Molecular-multiproxy assessment of land-derived organic matter degradation over extensive scales of the East Siberian Arctic Shelf seas	2 MB	Adobe Acrobat PDF	Read	Download
DOI Доступ к ресурсу на сайте издателя			10.1029/2022GB007428

#деградация

#органические вещества

#арктический шельф

#Восточная Сибирь

#терригенные отложения

Title: Molecular-multiproxy assessment of land-derived organic matter degradation over extensive scales of the East Siberian Arctic Shelf seas
Creator: Matsubara, Felipe
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Wild, Birgit
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Martens, Jannik
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Andersson, A.
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Wennström, R.
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Bröder, L.
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Dudarev, Oleg V.
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Semiletov, Igor P.
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Gustafsson, Örjan
Date: 2022
DOI: 10.1029/2022GB007428
Description: Global warming triggers permafrost thaw, which increases the release of terrigenous organic matter (terr-OM) to the Arctic Ocean by coastal erosion and rivers. Terrigenous OM degradation in the Arctic Ocean contributes to greenhouse gas emissions and severe ocean acidification, yet the vulnerability of different terr-OM components is poorly resolved. Here, terr-OM degradation dynamics are studied with unprecedented spatial coverage over the World's largest shelf sea system—the East Siberian Arctic Shelf (ESAS), using a multi-proxy molecular biomarker approach. Mineral-surface-area-normalized concentrations of terr-OM compounds in surface sediments decreases offshore. Differences between terr-OM compound classes (lignin phenols, high-molecular weight [HMW] n-alkanes, n-alkanoic acids and n-alkanols, sterols, 3,5-dihydroxybenzoic acids, cutin acids) reflect contrasting influence of sources, propensity to microbial degradation and association with sedimenting particles, with lignin phenols disappearing 3-times faster than total terr-OM, and twice faster than other biomarkers. Molecular degradation proxies support substantial terr-OM degradation across the ESAS, with clearest trends shown by: 3,5-dihydroxybenzoic acid/vanillyl phenol ratios, acid-to-aldehyde ratios of syringyl and vanillyl phenols, Carbon Preference Indices of HMW n-alkyl compounds and sitostanol/β-sitosterol. The combination of terr-OM biomarker data with δ13C/Δ14C-based source apportionment indicates that the more degraded state of lignin is influenced by the relative contribution of river-transported terr-OM from surface soils, while HMW n-alkanoic acids and stigmasterol are influenced by erosion-derived terr-OM from Ice Complex deposits. Our findings demonstrate differences in vulnerability to degradation between contrasting terr-OM pools, and underscore the need to consider molecular properties for understanding and modeling of large-scale biogeochemical processes of the permafrost carbon-climate feedback.

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collection(s): Научное управление
Identifier: смотреть в электронном каталоге НБ ТГУ
Type: статьи в журналах
Source: Global biogeochemical cycles. 2022. Vol. 36, № 12. P. e2022GB007428 (1-19)
Language: eng

Created: 21-11-2023

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Научное управление Molecular-multiproxy assessment of land-derived organic matter degradation over extensive scales of the East Siberian Arctic Shelf seas