Deglacial records of terrigenous organic matter accumulation off the Yukon and Amur rivers based on lignin phenols and long-chain n-alkanes
Arctic warming and sea level change will lead to widespread permafrost thaw and subsequent mobilization. Sedimentary records of past warming events during the Last Glacial–interglacial transition can be used to study the conditions under which permafrost mobilization occurs and which changes in vege...
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ftcopernicus:oai:publications.copernicus.org:cp105933 2023-05-15T14:56:38+02:00 Deglacial records of terrigenous organic matter accumulation off the Yukon and Amur rivers based on lignin phenols and long-chain n-alkanes Cao, Mengli Hefter, Jens Tiedemann, Ralf Lembke-Jene, Lester Meyer, Vera D. Mollenhauer, Gesine 2023-01-23 application/pdf https://doi.org/10.5194/cp-19-159-2023 https://cp.copernicus.org/articles/19/159/2023/ eng eng doi:10.5194/cp-19-159-2023 https://cp.copernicus.org/articles/19/159/2023/ eISSN: 1814-9332 Text 2023 ftcopernicus https://doi.org/10.5194/cp-19-159-2023 2023-01-30T17:22:43Z Arctic warming and sea level change will lead to widespread permafrost thaw and subsequent mobilization. Sedimentary records of past warming events during the Last Glacial–interglacial transition can be used to study the conditions under which permafrost mobilization occurs and which changes in vegetation on land are associated with such warming. The Amur and Yukon rivers discharging into the Okhotsk and Bering seas, respectively, drain catchments that have been, or remain until today, covered by permafrost. Here we study two marine sediment cores recovered off the mouths of these rivers. We use lignin phenols as biomarkers, which are excellently suited for the reconstruction of terrestrial higher plant vegetation, and compare them with previously published lipid biomarker data. We find that in the Yukon basin, vegetation change and wetland expansion began already in the early deglaciation (ED; 14.6–19 ka). This timing is different from observed changes in the Okhotsk Sea reflecting input from the Amur basin, where wetland expansion and vegetation change occurred later in the Pre-Boreal (PB). In the two basins, angiosperm contribution and wetland extent all reached maxima during the PB, both decreasing and stabilizing after the PB. The permafrost of the Amur basin began to become remobilized in the PB. Retreat of sea ice coupled with increased sea surface temperatures in the Bering Sea during the ED might have promoted early permafrost mobilization. In modern Arctic river systems, lignin and n -alkanes are transported from land to the ocean via different pathways, i.e., surface runoff vs. erosion of deeper deposits, respectively. However, accumulation rates of lignin phenols and lipids are similar in our records, suggesting that under conditions of rapid sea level rise and shelf flooding, both types of terrestrial biomarkers are delivered by the same transport pathway. This finding suggests that the fate of terrigenous organic matter in the Arctic differs on both temporal and spatial scales. Text Arctic Bering Sea Ice okhotsk sea permafrost Sea ice Yukon Basin Yukon Copernicus Publications: E-Journals Arctic Bering Sea Okhotsk Yukon Yukon Basin ENVELOPE(-135.000,-135.000,64.282,64.282) Climate of the Past 19 1 159 178 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Arctic warming and sea level change will lead to widespread permafrost thaw and subsequent mobilization. Sedimentary records of past warming events during the Last Glacial–interglacial transition can be used to study the conditions under which permafrost mobilization occurs and which changes in vegetation on land are associated with such warming. The Amur and Yukon rivers discharging into the Okhotsk and Bering seas, respectively, drain catchments that have been, or remain until today, covered by permafrost. Here we study two marine sediment cores recovered off the mouths of these rivers. We use lignin phenols as biomarkers, which are excellently suited for the reconstruction of terrestrial higher plant vegetation, and compare them with previously published lipid biomarker data. We find that in the Yukon basin, vegetation change and wetland expansion began already in the early deglaciation (ED; 14.6–19 ka). This timing is different from observed changes in the Okhotsk Sea reflecting input from the Amur basin, where wetland expansion and vegetation change occurred later in the Pre-Boreal (PB). In the two basins, angiosperm contribution and wetland extent all reached maxima during the PB, both decreasing and stabilizing after the PB. The permafrost of the Amur basin began to become remobilized in the PB. Retreat of sea ice coupled with increased sea surface temperatures in the Bering Sea during the ED might have promoted early permafrost mobilization. In modern Arctic river systems, lignin and n -alkanes are transported from land to the ocean via different pathways, i.e., surface runoff vs. erosion of deeper deposits, respectively. However, accumulation rates of lignin phenols and lipids are similar in our records, suggesting that under conditions of rapid sea level rise and shelf flooding, both types of terrestrial biomarkers are delivered by the same transport pathway. This finding suggests that the fate of terrigenous organic matter in the Arctic differs on both temporal and spatial scales. |
format |
Text |
author |
Cao, Mengli Hefter, Jens Tiedemann, Ralf Lembke-Jene, Lester Meyer, Vera D. Mollenhauer, Gesine |
spellingShingle |
Cao, Mengli Hefter, Jens Tiedemann, Ralf Lembke-Jene, Lester Meyer, Vera D. Mollenhauer, Gesine Deglacial records of terrigenous organic matter accumulation off the Yukon and Amur rivers based on lignin phenols and long-chain n-alkanes |
author_facet |
Cao, Mengli Hefter, Jens Tiedemann, Ralf Lembke-Jene, Lester Meyer, Vera D. Mollenhauer, Gesine |
author_sort |
Cao, Mengli |
title |
Deglacial records of terrigenous organic matter accumulation off the Yukon and Amur rivers based on lignin phenols and long-chain n-alkanes |
title_short |
Deglacial records of terrigenous organic matter accumulation off the Yukon and Amur rivers based on lignin phenols and long-chain n-alkanes |
title_full |
Deglacial records of terrigenous organic matter accumulation off the Yukon and Amur rivers based on lignin phenols and long-chain n-alkanes |
title_fullStr |
Deglacial records of terrigenous organic matter accumulation off the Yukon and Amur rivers based on lignin phenols and long-chain n-alkanes |
title_full_unstemmed |
Deglacial records of terrigenous organic matter accumulation off the Yukon and Amur rivers based on lignin phenols and long-chain n-alkanes |
title_sort |
deglacial records of terrigenous organic matter accumulation off the yukon and amur rivers based on lignin phenols and long-chain n-alkanes |
publishDate |
2023 |
url |
https://doi.org/10.5194/cp-19-159-2023 https://cp.copernicus.org/articles/19/159/2023/ |
long_lat |
ENVELOPE(-135.000,-135.000,64.282,64.282) |
geographic |
Arctic Bering Sea Okhotsk Yukon Yukon Basin |
geographic_facet |
Arctic Bering Sea Okhotsk Yukon Yukon Basin |
genre |
Arctic Bering Sea Ice okhotsk sea permafrost Sea ice Yukon Basin Yukon |
genre_facet |
Arctic Bering Sea Ice okhotsk sea permafrost Sea ice Yukon Basin Yukon |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-19-159-2023 https://cp.copernicus.org/articles/19/159/2023/ |
op_doi |
https://doi.org/10.5194/cp-19-159-2023 |
container_title |
Climate of the Past |
container_volume |
19 |
container_issue |
1 |
container_start_page |
159 |
op_container_end_page |
178 |
_version_ |
1766328722574540800 |