Soil organic carbon stocks along transects from Yedoma uplands into drained thaw lake basins on Sobo-Sise Island, Lena Delta, Siberia
Late Pleistocene ice-rich syngenetic permafrost deposits called Yedoma store large amounts of organic carbon and are highly affected by climate warming and permafrost degradation. Permafrost thaw, ice-wedge melt, and thermokarst processes affect and expose these carbon-rich deposits to increased mic...
| Main Authors: | , , |
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| Format: | Conference Object |
| Language: | unknown |
| Published: |
2016
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| Subjects: | |
| Online Access: | https://epic.awi.de/id/eprint/41264/ https://hdl.handle.net/10013/epic.48207 |
| Summary: | Late Pleistocene ice-rich syngenetic permafrost deposits called Yedoma store large amounts of organic carbon and are highly affected by climate warming and permafrost degradation. Permafrost thaw, ice-wedge melt, and thermokarst processes affect and expose these carbon-rich deposits to increased microbial activity. Therefore, organic carbon which has been protected by permafrost for thousands of years may partially be released to the atmosphere as greenhouse gases CO2 and CH4. However the fate of this low decomposed carbon and the amount and distribution of carbon stored in Yedoma uplands and deposits of thermokarst landforms is still discussed. Our study aims to present a detailed comparison of near-surface organic carbon and nitrogen stocks up to 3m depth in Yedoma uplands as well as thermokarst basins along two permafrost coring transects. The transects are located on Sobo-Sise Island in the eastern part of the Lena river delta (NE Siberia) and cover different stages of Yedoma degradation including adjacent deltaic deposits. Sobo-Sise Island is characterized by Yedoma uplands (third Lena River Delta terrace) which are fragmented by thaw-induced erosion and thermokarst landforms. Inventarization of relief units revealed that about one quarter (86 km2) of Sobo-Sise is covered by Yedoma and an additional 28% (95 km2) is covered by partially eroded Yedoma slopes between Yedoma and surrounding drained thaw lake basins or river channels. 11% (38 km2) are covered by lakes or rivers and the remaining area (117 km2 or 35%) is covered by drained thaw lake basins (DTLB). Our approach is based on transect based soil sampling including sample locations on Yedoma uplands, slopes, and adjacent drained thaw lake basins of different generations as well as delta floodplains. Two transects were sampled which run from Yedoma uplands into thermokarst basins in equidistant intervals between the sampling points. In total 15 locations have been sampled with soil pits for the active layer portion and a SIPRE corer for the underlying ... |
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