The permafrost thaw fingerprint: the Isotopic composition of Particulate Organic Carbon From Lena River to Laptev sea
Rapid climate warming in the Arctic region intensifies permafrost thaw, increases active layer depth in summer and enhances riverbank and coastal erosion. This causes the release of organic matter (OM) into streams and rivers and result in discharge of terrestrial OM into the Arctic Ocean. The focus...
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2021
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Online Access: | https://epic.awi.de/id/eprint/53923/ https://hdl.handle.net/10013/epic.51b081e9-611a-49e9-a9a0-88247535369d |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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Rapid climate warming in the Arctic region intensifies permafrost thaw, increases active layer depth in summer and enhances riverbank and coastal erosion. This causes the release of organic matter (OM) into streams and rivers and result in discharge of terrestrial OM into the Arctic Ocean. The focus of our study, particulate OM (POM) consists of a complex mixture of compounds from different sources with different chemical/physical resistance towards decomposition and mineralization. Particulate organic carbon (POC) transported by the Lena River represents a quantitatively important carbon pool exported to the Laptev Sea, but its quantity, quality, transport and transformation features are still not fully understood. With this study, we determined the sources (e.g., permafrost, soil, peat, phytoplankton, vegetation, etc.), quality and age of organic carbon transported by Arctic rivers to understand the effects of climate change on the river watersheds as well as on the Arctic coastal nearshore zone. Our study is embedded into the project ‘Changing Arctic Carbon cycle in the cOastal Ocean Nearshore (CACOON)’, which aims to investigate composition, seasonal effect, and changes during the transport and further fate of organic matter discharged by the Lena River to the Laptev sea (see Strauss et al 2021, this abstract book). To assess these data, we have had an intensive fieldwork in the Russian Arctic in summer 2019. Samples were collected across a ~1500 km transect from the Yakutsk through the centre of the Lena Delta to the Nearshore zone, covering the fresh-salt water transition. We analysed water samples from one to three different water depths to capture stratification in the water column. In a next step, the water was filtered at Samoylov Research Station through precombusted GF/F filters (25 mm diameter). Filters with POM were stored frozen in precombusted glass petri dishes. Later, the filters were analysed at AWI Bremerhaven for total suspended matter, total POC concentration, stable (δ13C) and radiocarbon (Δ14C) isotopes. We found significant qualitative and quantitative differences between the OM composition in the Lena River main channel and its delta. Further, we found suspended matter and POC concentrations decreased during the transit from the river to the Arctic Ocean. We demonstrate that deltaic POC is depleted in 13C relative to fluvial POC, and that its 14C signature suggests a modern composition indicating phytoplankton origin. This observation likely reflects the difference in hydrological conditions between the delta and the river main channel, caused by lower flow velocity and average water depth. |
format |
Conference Object |
author |
Ogneva, Olga Mollenhauer, Gesine Grotheer, Hendrik Fuchs, Matthias Palmtag, Juri Mann, Paul James Strauss, Jens |
spellingShingle |
Ogneva, Olga Mollenhauer, Gesine Grotheer, Hendrik Fuchs, Matthias Palmtag, Juri Mann, Paul James Strauss, Jens The permafrost thaw fingerprint: the Isotopic composition of Particulate Organic Carbon From Lena River to Laptev sea |
author_facet |
Ogneva, Olga Mollenhauer, Gesine Grotheer, Hendrik Fuchs, Matthias Palmtag, Juri Mann, Paul James Strauss, Jens |
author_sort |
Ogneva, Olga |
title |
The permafrost thaw fingerprint: the Isotopic composition of Particulate Organic Carbon From Lena River to Laptev sea |
title_short |
The permafrost thaw fingerprint: the Isotopic composition of Particulate Organic Carbon From Lena River to Laptev sea |
title_full |
The permafrost thaw fingerprint: the Isotopic composition of Particulate Organic Carbon From Lena River to Laptev sea |
title_fullStr |
The permafrost thaw fingerprint: the Isotopic composition of Particulate Organic Carbon From Lena River to Laptev sea |
title_full_unstemmed |
The permafrost thaw fingerprint: the Isotopic composition of Particulate Organic Carbon From Lena River to Laptev sea |
title_sort |
permafrost thaw fingerprint: the isotopic composition of particulate organic carbon from lena river to laptev sea |
publishDate |
2021 |
url |
https://epic.awi.de/id/eprint/53923/ https://hdl.handle.net/10013/epic.51b081e9-611a-49e9-a9a0-88247535369d |
long_lat |
ENVELOPE(-73.182,-73.182,-71.649,-71.649) |
geographic |
Arctic Arctic Ocean Laptev Sea Yakutsk Strauss |
geographic_facet |
Arctic Arctic Ocean Laptev Sea Yakutsk Strauss |
genre |
Arctic Arctic Ocean Climate change laptev Laptev Sea lena delta lena river permafrost Phytoplankton Yakutsk |
genre_facet |
Arctic Arctic Ocean Climate change laptev Laptev Sea lena delta lena river permafrost Phytoplankton Yakutsk |
op_source |
EPIC3International Symposium 'Focus Siberian Permafrost – Terrestrial Cryosphere and Climate Change', 2021-03-24-2021-03-25 |
op_relation |
Ogneva, O. orcid:0000-0002-9309-2076 , Mollenhauer, G. orcid:0000-0001-5138-564X , Grotheer, H. orcid:0000-0003-0207-3767 , Fuchs, M. orcid:0000-0003-3529-8284 , Palmtag, J. orcid:0000-0002-6921-5697 , Mann, P. J. orcid:0000-0002-6221-3533 and Strauss, J. orcid:0000-0003-4678-4982 (2021) The permafrost thaw fingerprint: the Isotopic composition of Particulate Organic Carbon From Lena River to Laptev sea , International Symposium 'Focus Siberian Permafrost – Terrestrial Cryosphere and Climate Change', 24 March 2021 - 25 March 2021 . hdl:10013/epic.51b081e9-611a-49e9-a9a0-88247535369d |
_version_ |
1766319831696539648 |
spelling |
ftawi:oai:epic.awi.de:53923 2023-05-15T14:48:45+02:00 The permafrost thaw fingerprint: the Isotopic composition of Particulate Organic Carbon From Lena River to Laptev sea Ogneva, Olga Mollenhauer, Gesine Grotheer, Hendrik Fuchs, Matthias Palmtag, Juri Mann, Paul James Strauss, Jens 2021 https://epic.awi.de/id/eprint/53923/ https://hdl.handle.net/10013/epic.51b081e9-611a-49e9-a9a0-88247535369d unknown Ogneva, O. orcid:0000-0002-9309-2076 , Mollenhauer, G. orcid:0000-0001-5138-564X , Grotheer, H. orcid:0000-0003-0207-3767 , Fuchs, M. orcid:0000-0003-3529-8284 , Palmtag, J. orcid:0000-0002-6921-5697 , Mann, P. J. orcid:0000-0002-6221-3533 and Strauss, J. orcid:0000-0003-4678-4982 (2021) The permafrost thaw fingerprint: the Isotopic composition of Particulate Organic Carbon From Lena River to Laptev sea , International Symposium 'Focus Siberian Permafrost – Terrestrial Cryosphere and Climate Change', 24 March 2021 - 25 March 2021 . hdl:10013/epic.51b081e9-611a-49e9-a9a0-88247535369d EPIC3International Symposium 'Focus Siberian Permafrost – Terrestrial Cryosphere and Climate Change', 2021-03-24-2021-03-25 Conference notRev 2021 ftawi 2021-12-24T15:46:16Z Rapid climate warming in the Arctic region intensifies permafrost thaw, increases active layer depth in summer and enhances riverbank and coastal erosion. This causes the release of organic matter (OM) into streams and rivers and result in discharge of terrestrial OM into the Arctic Ocean. The focus of our study, particulate OM (POM) consists of a complex mixture of compounds from different sources with different chemical/physical resistance towards decomposition and mineralization. Particulate organic carbon (POC) transported by the Lena River represents a quantitatively important carbon pool exported to the Laptev Sea, but its quantity, quality, transport and transformation features are still not fully understood. With this study, we determined the sources (e.g., permafrost, soil, peat, phytoplankton, vegetation, etc.), quality and age of organic carbon transported by Arctic rivers to understand the effects of climate change on the river watersheds as well as on the Arctic coastal nearshore zone. Our study is embedded into the project ‘Changing Arctic Carbon cycle in the cOastal Ocean Nearshore (CACOON)’, which aims to investigate composition, seasonal effect, and changes during the transport and further fate of organic matter discharged by the Lena River to the Laptev sea (see Strauss et al 2021, this abstract book). To assess these data, we have had an intensive fieldwork in the Russian Arctic in summer 2019. Samples were collected across a ~1500 km transect from the Yakutsk through the centre of the Lena Delta to the Nearshore zone, covering the fresh-salt water transition. We analysed water samples from one to three different water depths to capture stratification in the water column. In a next step, the water was filtered at Samoylov Research Station through precombusted GF/F filters (25 mm diameter). Filters with POM were stored frozen in precombusted glass petri dishes. Later, the filters were analysed at AWI Bremerhaven for total suspended matter, total POC concentration, stable (δ13C) and radiocarbon (Δ14C) isotopes. We found significant qualitative and quantitative differences between the OM composition in the Lena River main channel and its delta. Further, we found suspended matter and POC concentrations decreased during the transit from the river to the Arctic Ocean. We demonstrate that deltaic POC is depleted in 13C relative to fluvial POC, and that its 14C signature suggests a modern composition indicating phytoplankton origin. This observation likely reflects the difference in hydrological conditions between the delta and the river main channel, caused by lower flow velocity and average water depth. Conference Object Arctic Arctic Ocean Climate change laptev Laptev Sea lena delta lena river permafrost Phytoplankton Yakutsk Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Arctic Arctic Ocean Laptev Sea Yakutsk Strauss ENVELOPE(-73.182,-73.182,-71.649,-71.649) |