HR: 0800h
AN: B31A-0204    [Abstracts]
TI: The Role of the Permafrost Reservoir in the Global Carbon Budget
AU: * Zimov, S
EM: sazimov@cher.sakha.ru
AF: Northeast Science Station of Cherskii, Russian Academy of Sciences, PO Box 18, Cherskii, 678830 Russian Federation
AU: Davydov, S
EM: sazimov@cher.sakha.ru
AF: Northeast Science Station of Cherskii, Russian Academy of Sciences, PO Box 18, Cherskii, 678830 Russian Federation
AU: Zimova, G
EM: sazimov@cher.sakha.ru
AF: Northeast Science Station of Cherskii, Russian Academy of Sciences, PO Box 18, Cherskii, 678830 Russian Federation
AU: Davydova, A I
EM: sazimov@cher.sakha.ru
AF: Northeast Science Station of Cherskii, Russian Academy of Sciences, PO Box 18, Cherskii, 678830 Russian Federation
AU: Zimov, N S
EM: sazimov@cher.sakha.ru
AF: Northeast Science Station of Cherskii, Russian Academy of Sciences, PO Box 18, Cherskii, 678830 Russian Federation
AU: Chuprynin, V I
AF: Institute for Geography, Russian Academy of Sciences, 1 Radio Ave, Vladivostok, 678830 Russian Federation
AU: Molchanova, L A
AF: Far East State University, 10 Lenin Prospect, Vladivostok, 678830 Russian Federation
AU: Schuur, T
EM: tschuur@ufl.edu
AF: Department of Botany, University of Florida, 220 Bartram Hall PO Box 118526, Gainesville, FL 32611 Russian Federation
AU: Chapin, F S
EM: terry.chapin@uaf.edu
AF: Insitute of Arctic Biology, University of Alaska PO Box 757000, Fairbanks, AK 99775 United States
AB: A high organic content is typical for all frozen sediments accumulated on permafrost, because these sediments are per se cryopreserved soils. The most interesting of these types of sediments is the frozen Pleistocene loess. It is the soil of the mammoth tundra-steppe. It covers about one million square kilometers of the north of Siberia. Carbon content of the soil is about 2%. Total carbon storage in the sediments is about 400 Gt. For many years, experiments and field measurements showed that the carbon is highly labile. The soils respire upon thawing at a rate of 3 to 20 mg C/kg/day. In the case of vast thawing of the sediments, CO$_{2}$ emission connected with this will be comparable with anthropogenic emission. Field experiments and modeling showed that the thermal flux connected with Pleistocene soil respiration upon thawing (self-heating) may provide progressive permafrost melting. It is accepted that during the Pleistocene glaciation, carbon storage in terrestrial ecosystems was reduced to about 500 Gt (0 to 1350 Gt range) . But during that time, the permafrost zone occupied all the territory north of 40-45$^{o}$ N. By making an analogy with carbon content in preserved frozen sediments in Siberia and Alaska we can suppose that terrestrial carbon storage during glaciation was 1500 to 2000 Gt higher than present assessments. The value includes carbon storage in large-scale tundra-steppe biomes; in frozen loess of Europe and the southwest of Siberia; in solifluction sediments of slopes and in alluvium; in soil, loess and peat buried under glacial sheets. Thawing of permafrost and glaciers was accompanied by oxidation of the carbon and CO$_{2}$ emission into the atmosphere. Data of the Pleistocene-Holocene dynamic of atmospheric CO$_{2}$ and $^{14}$C corresponds to the permafrost reservoir dynamic. Budget of $^{13}$ CO$_{2}$ corresponds to this dynamic only under conditions when the storage of organic carbon in the ocean during glaciation was significantly reduced.
DE: 1823 Frozen ground
DE: 1851 Plant ecology
DE: 1863 Snow and ice (1827)
DE: 0315 Biosphere/atmosphere interactions
DE: 0325 Evolution of the atmosphere
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting