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Abstracts
SEARCH Open Science Meeting
October 27, 2003
Seattle, Washington, USA
The Spatio-Temporal Pattern of Peatland Development in the Western Siberian Lowlands and the Potential Impact of Northern Peatlands on the Global Carbon Cycle
Glen M. MacDonald1, Lawerence Smith2, Konstantine Kremenetski3, Yongwei Sheng4, David Beilman5, Karen Frey6, Andrei Velichko7
1Department of Geography, UCLA, 405 Hilgard Ave., Los Angeles, CA, CA, 90095, USA, Phone 310-825-1071, Fax 310-206-5976, macdonal@geog.ucla.edu
2Department of Geography, UCLA, 405 Hilgard Ave., Los Angeles, CA, 91361, USA, Phone 310-825-3154, Fax 310-206-5976, lsmith@geog.ucla.edu
3Department of Geography, UCLA, 405 Hilgard Ave., Los Angeles, CA, 91361, USA
4Department of Geography, UCLA, 405 Hilgard Ave., Los Angeles, CA, USA, ysheng@geog.ucla.edu
5Department of Geography, UCLA, 405 Hilgard Ave., Los Angeles, CA, USA, Phone 310-206-2261, Fax 310-914-9008, dbeilman@ucla.edu
6Department of Geography, UCLA, 405 Hilgard Ave., Los Angeles, CA, USA, Phone 310-206-2261, Fax 310-206-5976, frey@ucla.edu
7Laboratory of Evolutionary Geography, nstitute of Geography, Russian Academyof Science, Staromonetny Street 29, Moscow, 109017, Russia
The largest northern peatland complex in the world is found in the Western Siberian Lowlands (WSL) and covers some 600,000 km2. The development of high latitude peatlands was an important component in postglacial landscape development and significantly impacted the hydrology, flora, fauna and human occupants of the subarctic. In addition, peatland development influenced atmospheric carbon concentrations through the opposing impacts of sequestering carbon and generating methane. Understanding the temporal and spatial history of high latitude peatlands is critical to understanding the dynamics of the global carbon cycle.
We radiocarbon dated the basal peats from 87 cores taken from 60 N to the Arctic coastline in the WSL. Combined with existing Russian radiocarbon dates this provided over 100 age estimates for the initial formation of peatlands in the WSL. In order to develop a circumpolar history of peatland initiation we collated published basal radiocarbon dates from subarctic peatlands in North America and Eurasia. The results indicate that subarctic peatland development commenced in the early Holocene- by around 11,500-11,000 CAL yr BP in the WSL and some ice-free areas of North America. This period of initial peatland development also coincides with the development of northern boreal forest in Siberia.
Peatland initiation in the WSL does not show a strong latitudinal or longitudinal pattern. In contrast, the southern fringes of the current peatland zone in central Canada mainly developed in the late Holocene. Carbon analysis of the WSL cores and the GIS based analysis of new and older Our core data combined with Russian peat depth data provide a new peat carbon pool estimate of 70.2 Pg C for the WSL. This value is highly conservative because like previous investigators we do not consider thin peats (<50 cm) in our inventory and we conservatively assume 52% peat organic carbon content. However, even at 70.2 Pg C the WSL represents a substantial Holocene carbon sink, averaging 6.1 Tg C yr-1 over the past ~11.5 ka. However, a strong peak in peatland initiation in the WSL between 11,500 and 9000 CAL yr BP also coincides with increased levels of atmospheric methane attributable to high latitude sources in the northern hemisphere. The release of carbon from long-term storage in northern peatlands, particularly if it involved the genration of methane, would have a significant impact upon atmosphic carbon and climate change.
Abstract Categories: Changes on Land
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