气候变化领域集成服务门户(CCPortal): Selective Sorting and Degradation of Permafrost Organic Matter in the Nearshore Zone of Herschel Island (Yukon, Canada)

CCPortal

DOI	10.1029/2023JG007479
	Selective Sorting and Degradation of Permafrost Organic Matter in the Nearshore Zone of Herschel Island (Yukon, Canada)
	Jong, Dirk; Broder, Lisa; Tesi, Tommaso; Tanski, George; Oudenhuijsen, Mickolai; Fritz, Michael; Lantuit, Hugues; Haghipour, Negar; Eglinton, Timothy; Vonk, Jorien
发表日期	2024
ISSN	2169-8953
EISSN	2169-8961
起始页码	129
结束页码	1
卷号	129 期号:1
英文摘要	Erosion of permafrost coasts due to climate warming releases large quantities of organic carbon (OC) into the Arctic Ocean. While burial of permafrost OC in marine sediments potentially limits degradation, resuspension of sediments in the nearshore zone potentially enhances degradation and greenhouse gas production, adding to the permafrost carbon feedback. Recent studies, focusing on bulk sediments, suggest that permafrost OC derived from coastal erosion is predominantly deposited close to shore. However, bulk approaches disregard sorting processes in the coastal zone, which strongly influence the OC distribution and fate. We studied soils and sediments along a transect from the fast-eroding shoreline of Herschel Island-Qikiqtaruk (Yukon, Canada) to a depositional basin offshore. Sample material was fractionated by density (1.8 g cm-3) and size (63 mu m), separating loose OC from mineral-associated OC. Each fraction was analyzed for element content (TOC, TN), carbon isotopes (delta 13C, Delta 14C), molecular biomarkers (n-alkanes, n-alkanoic acids, lignin phenols, cutin acids), and mineral surface area. The OC partitioning between fractions changes considerably along the transect, highlighting the importance of hydrodynamic sorting in the nearshore zone. Additionally, OC and biomarker loadings decrease along the land-ocean transect, indicating significant loss of OC during transport. However, molecular proxies for degradation show contrasting trends, suggesting that OC losses are not always well reflected in its degradation state. This study, using fraction partitioning that crosses land-ocean boundaries in a way not done before, aids to disentangle sorting processes from degradation patterns, and provides quantitative insight into losses of thawed and eroded permafrost OC. The Arctic coastline is vulnerable for erosion, since it mostly consist of permafrost (permanently frozen ground), which undergoes rapid warming due to climate change. Thaw and erosion of permafrost along the coast releases organic carbon (OC), that has been stored for millennia, into the ocean. There, in the ocean, this carbon can be degraded back into CO2, potentially enforcing climate warming, or it can settle to the sediments, and potentially be stored again for millennia. The permafrost and the sediment consist of particles, for example, sand, silt, and clay, and loose fragments of vegetation. In this study, we separated the OC that is associated with fine particles (silt and clay) from the loose fragments of organic matter. We observe that these two fractions of sediment have a very different composition and source, and end up somewhere else in the marine system. This study further shows that a large part of the OC associated with minerals (silt and clay) is lost during transport, but also that indicators for degradation show contrasting results. Overall, we highlight the importance of looking at sediment fractions separately, and also emphasize studying the transitional zone between land to ocean for the permafrost carbon cycle. Size and density fractionation of sediment organic carbon (OC) reveals substantial contrasts between different fractions and environmentsOC- and biomarker loading shows that a significant amount of terrestrial OC is lost along a land-ocean transectCombining methods in dynamic environments such as the nearshore zone is key in studying the fate of permafrost OC
英文关键词	permafrost; organic carbon; sediment; biomarkers; fractionation; nearshore zone
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Geology
WOS类目	Environmental Sciences ; Geosciences, Multidisciplinary
WOS记录号	WOS:001144852800001
来源期刊	JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/306697
作者单位	Vrije Universiteit Amsterdam; Swiss Federal Institutes of Technology Domain; ETH Zurich; Consiglio Nazionale delle Ricerche (CNR); Istituto di Scienze Polari (ISP-CNR); Helmholtz Association; Alfred Wegener Institute, Helmholtz Centre for Polar & Marine Research; University of Potsdam
推荐引用方式 GB/T 7714	Jong, Dirk,Broder, Lisa,Tesi, Tommaso,et al. Selective Sorting and Degradation of Permafrost Organic Matter in the Nearshore Zone of Herschel Island (Yukon, Canada)[J],2024,129(1).
APA	Jong, Dirk.,Broder, Lisa.,Tesi, Tommaso.,Tanski, George.,Oudenhuijsen, Mickolai.,...&Vonk, Jorien.(2024).Selective Sorting and Degradation of Permafrost Organic Matter in the Nearshore Zone of Herschel Island (Yukon, Canada).JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES,129(1).
MLA	Jong, Dirk,et al."Selective Sorting and Degradation of Permafrost Organic Matter in the Nearshore Zone of Herschel Island (Yukon, Canada)".JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES 129.1(2024).