Carbon Pool of Permafrost in Kolyma-Indigirka Lowland

Denis Shmelev, Institute of Physical Chemical and Biological Problems of Soil Science, Pushchino, Russia, Alexandra Veremeeva, Institute of Physicochemical and Biological Problems in Soil Science, Pushchino, Russia, Gleb Kraev, Center of Ecology and Productivity of Forests, Moscow, Russia, Alexander L Kholodov, University of Alaska Fairbanks, Geophysical Institute, Fairbanks, AK, United States and Elizaveta Rivkina, Institute of Physiochemical and Biological Problems in Soil Science, Pushchino, Russia
Abstract:
The original database of total carbon, bulk density and iciness and new Geological map were compiled for carbon pool permafrost estimating in Quaternary deposits of North East Yakutia. The database was based on original drilling data on the main Quaternary stratigraphic units of Kolyma-Indigirka Lowland (12 key sites, 120 boreholes, 1000 samples). New geological map was created according Landsat-7 Satellite Image (spatial resolution - 30 m), the State Geological map of Quaternary Deposits (2000) and our field investigation for last 30 years in studying region. Studying area was divided into 3 regions according stratigraphy: East of Yana-Indigirka Lowland, Chukochya and Alazeya Rivers basins, East of Kolyma Lowland. Estimating was compiled for upper 25 m thickness.

4 main geomorphological levels were selected for calculation: yedoma (12,8% of total area), alasses (48%), river valley (20,9%) and coastal accumulative lowland (16,7%). Our studies shows, that distribution of yedoma was overestimated in 3,5 times by State Geological Map, mainly due to underestimating of allases (increasing area on 60%).

According our assessment, inorganic carbon doesn’t exceed 10% of total carbon in the studying area. Permafrost stratigraphic units contain 0.6-2.1% of TC, with the highest concentrations found in Cover Layer and Ice Complex (Yedoma). The biggest carbon pool is found in Olyor, which refers to the most widespread sediments studied and high carbon concentration (up to 18 kg*m-3). The TC pool of Yedoma was 1.5-2 times overestimated by previous studies due to less samples and underestimated iciness. The TC pool of Kolyma delta is 5-7 times overestimated because of higher total organic carbon values considered. Taking the morphology into account, the TC pool assessed is 23.4 ± 9.5 Gt at near 95 000 km2 area. Mean specific carbon content is around 9.9 kg*m-3 in Kolyma Lowland permafrost. The stratigraphic unit-based approach used to compile the database and its analysis provides detailed study of carbon storage in Arctic permafrost. It is well organized for adequately forecasting of permafrost degradation consequences for carbon cycle, including activation of microbiological processes and greenhouse gases emissions.

This research was supported by Russian Scientific Fund, Grant RSF 14-14-01115

Back to: Vulnerability of Permafrost Carbon to Climate Change II