Thermokarst Landscape Evolution Recorded by n-Alkanes in a Deep Sediment Core from Bykovsky Peninsula, Northeast Siberia
Warming of the Arctic triggers deep permafrost thaw, which has a strong impact on permafrost organic carbon (OC) storage. To identify the sedimentation history and organic matter (OM) characteristics of thermokarst-affected permafrost landscapes, we carried out an expedition in spring 2017 to the By...
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ftawi:oai:epic.awi.de:53784 2024-09-15T18:17:35+00:00 Thermokarst Landscape Evolution Recorded by n-Alkanes in a Deep Sediment Core from Bykovsky Peninsula, Northeast Siberia Jongejans, Loeka L. Mangelsdorf, Kai Liebner, Susanne Schirrmeister, Lutz Grigoriev, Mikhail Maksimov, Georgy T. Biskaborn, Boris K. Grosse, Guido Wagner, Dirk Strauss, Jens 2020-12-14 https://epic.awi.de/id/eprint/53784/ https://agu.confex.com/agu/fm20/meetingapp.cgi/Paper/671643 https://hdl.handle.net/10013/epic.1d404502-a513-4b0b-8d01-bce2c0eec5c8 unknown AGU Jongejans, L. L. orcid:0000-0002-0383-4567 , Mangelsdorf, K. , Liebner, S. , Schirrmeister, L. orcid:0000-0001-9455-0596 , Grigoriev, M. , Maksimov, G. T. , Biskaborn, B. K. orcid:0000-0003-2378-0348 , Grosse, G. orcid:0000-0001-5895-2141 , Wagner, D. and Strauss, J. orcid:0000-0003-4678-4982 (2020) Thermokarst Landscape Evolution Recorded by n-Alkanes in a Deep Sediment Core from Bykovsky Peninsula, Northeast Siberia , AGU Fall Meeting 2020, Virtual/Online, 1 December 2020 - 17 December 2020 . hdl:10013/epic.1d404502-a513-4b0b-8d01-bce2c0eec5c8 EPIC3AGU Fall Meeting 2020, Virtual/Online, 2020-12-01-2020-12-17AGU Conference notRev 2020 ftawi 2024-06-24T04:26:11Z Warming of the Arctic triggers deep permafrost thaw, which has a strong impact on permafrost organic carbon (OC) storage. To identify the sedimentation history and organic matter (OM) characteristics of thermokarst-affected permafrost landscapes, we carried out an expedition in spring 2017 to the Bykovsky Peninsula. This is a remnant of a late Pleistocene accumulation plain on the Laptev Sea coast, northeastern Siberia. We retrieved a 31-m-long sediment core from underneath a thermokarst lake (water depth: 5.1 m) and analyzed the sediments for n-alkanes, total organic carbon content (TOC) and grain size. From the bottom upwards, the core contained 3 m of frozen sediments from underneath the thaw bulb (Unit I: 36.6-33 m), 25 m of unfrozen Yedoma (taberal) sediments (Unit II: 33-18 m, Unit III: 18-10 m) and 4 m of unfrozen lake sediments (Unit IV: 10-5.1 m). Unit I contained coarsest sediments and rounded pebbles, which point to a strong fluvial influence. Here, we found the highest TOC values (17.8 wt%) and drift wood (organic remains up to 4 cm in size). The dominant mid-chains n-alkanes n-C23 and n-C25 and a high aquatic plant n-alkane proxy Paq (median: 0.65) suggest the growth of submerged/floating macrophytes. With a value of 2.2, the odd-over-even predominance (OEP) is lowest in Unit I. Unit II has a lower relative distribution of the midchain n-alkanes, which suggests the vegetation was likely emergent rather than submerged (median Paq: 0.44). This indicates the onset of Yedoma formation and low-centered polygon development. In the finer sediments of Unit III, the Paq further decreases (median: 0.32) and n-C31 becomes more important, indicating the transition to a drier, grass dominated environment. The thermokarst lake (Unit IV) formed about 8 cal ka BP, indicated by a peat layer. The OM in Unit IV is fresh (median OEP: 8.4) and has the highest n-alkane concentration (20.8 µg g-1 sediment). In this study, we show that thermokarst formation has a potential of mobilizing a large OC pool to tens of meters ... Conference Object laptev Laptev Sea permafrost Thermokarst Siberia Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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Open Polar |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
Warming of the Arctic triggers deep permafrost thaw, which has a strong impact on permafrost organic carbon (OC) storage. To identify the sedimentation history and organic matter (OM) characteristics of thermokarst-affected permafrost landscapes, we carried out an expedition in spring 2017 to the Bykovsky Peninsula. This is a remnant of a late Pleistocene accumulation plain on the Laptev Sea coast, northeastern Siberia. We retrieved a 31-m-long sediment core from underneath a thermokarst lake (water depth: 5.1 m) and analyzed the sediments for n-alkanes, total organic carbon content (TOC) and grain size. From the bottom upwards, the core contained 3 m of frozen sediments from underneath the thaw bulb (Unit I: 36.6-33 m), 25 m of unfrozen Yedoma (taberal) sediments (Unit II: 33-18 m, Unit III: 18-10 m) and 4 m of unfrozen lake sediments (Unit IV: 10-5.1 m). Unit I contained coarsest sediments and rounded pebbles, which point to a strong fluvial influence. Here, we found the highest TOC values (17.8 wt%) and drift wood (organic remains up to 4 cm in size). The dominant mid-chains n-alkanes n-C23 and n-C25 and a high aquatic plant n-alkane proxy Paq (median: 0.65) suggest the growth of submerged/floating macrophytes. With a value of 2.2, the odd-over-even predominance (OEP) is lowest in Unit I. Unit II has a lower relative distribution of the midchain n-alkanes, which suggests the vegetation was likely emergent rather than submerged (median Paq: 0.44). This indicates the onset of Yedoma formation and low-centered polygon development. In the finer sediments of Unit III, the Paq further decreases (median: 0.32) and n-C31 becomes more important, indicating the transition to a drier, grass dominated environment. The thermokarst lake (Unit IV) formed about 8 cal ka BP, indicated by a peat layer. The OM in Unit IV is fresh (median OEP: 8.4) and has the highest n-alkane concentration (20.8 µg g-1 sediment). In this study, we show that thermokarst formation has a potential of mobilizing a large OC pool to tens of meters ... |
format |
Conference Object |
author |
Jongejans, Loeka L. Mangelsdorf, Kai Liebner, Susanne Schirrmeister, Lutz Grigoriev, Mikhail Maksimov, Georgy T. Biskaborn, Boris K. Grosse, Guido Wagner, Dirk Strauss, Jens |
spellingShingle |
Jongejans, Loeka L. Mangelsdorf, Kai Liebner, Susanne Schirrmeister, Lutz Grigoriev, Mikhail Maksimov, Georgy T. Biskaborn, Boris K. Grosse, Guido Wagner, Dirk Strauss, Jens Thermokarst Landscape Evolution Recorded by n-Alkanes in a Deep Sediment Core from Bykovsky Peninsula, Northeast Siberia |
author_facet |
Jongejans, Loeka L. Mangelsdorf, Kai Liebner, Susanne Schirrmeister, Lutz Grigoriev, Mikhail Maksimov, Georgy T. Biskaborn, Boris K. Grosse, Guido Wagner, Dirk Strauss, Jens |
author_sort |
Jongejans, Loeka L. |
title |
Thermokarst Landscape Evolution Recorded by n-Alkanes in a Deep Sediment Core from Bykovsky Peninsula, Northeast Siberia |
title_short |
Thermokarst Landscape Evolution Recorded by n-Alkanes in a Deep Sediment Core from Bykovsky Peninsula, Northeast Siberia |
title_full |
Thermokarst Landscape Evolution Recorded by n-Alkanes in a Deep Sediment Core from Bykovsky Peninsula, Northeast Siberia |
title_fullStr |
Thermokarst Landscape Evolution Recorded by n-Alkanes in a Deep Sediment Core from Bykovsky Peninsula, Northeast Siberia |
title_full_unstemmed |
Thermokarst Landscape Evolution Recorded by n-Alkanes in a Deep Sediment Core from Bykovsky Peninsula, Northeast Siberia |
title_sort |
thermokarst landscape evolution recorded by n-alkanes in a deep sediment core from bykovsky peninsula, northeast siberia |
publisher |
AGU |
publishDate |
2020 |
url |
https://epic.awi.de/id/eprint/53784/ https://agu.confex.com/agu/fm20/meetingapp.cgi/Paper/671643 https://hdl.handle.net/10013/epic.1d404502-a513-4b0b-8d01-bce2c0eec5c8 |
genre |
laptev Laptev Sea permafrost Thermokarst Siberia |
genre_facet |
laptev Laptev Sea permafrost Thermokarst Siberia |
op_source |
EPIC3AGU Fall Meeting 2020, Virtual/Online, 2020-12-01-2020-12-17AGU |
op_relation |
Jongejans, L. L. orcid:0000-0002-0383-4567 , Mangelsdorf, K. , Liebner, S. , Schirrmeister, L. orcid:0000-0001-9455-0596 , Grigoriev, M. , Maksimov, G. T. , Biskaborn, B. K. orcid:0000-0003-2378-0348 , Grosse, G. orcid:0000-0001-5895-2141 , Wagner, D. and Strauss, J. orcid:0000-0003-4678-4982 (2020) Thermokarst Landscape Evolution Recorded by n-Alkanes in a Deep Sediment Core from Bykovsky Peninsula, Northeast Siberia , AGU Fall Meeting 2020, Virtual/Online, 1 December 2020 - 17 December 2020 . hdl:10013/epic.1d404502-a513-4b0b-8d01-bce2c0eec5c8 |
_version_ |
1810455647219613696 |