Peatland ecosystems are significant components in the global carbon cycle, as they have sequestered from the atmosphere the largest single terrestrial carbon stock as organic soils over the course of the Holocene (the last 11,000 years). Peatland ecosystems also are one of the most important contemporary sources of atmospheric methane. Research from a range of high-latitude locations using a variety of methods has revealed that northern peatlands are highly sensitive to climatic variation, to the extent that they can switch interannually from net atmospheric carbon sinks to net carbon sources. The future role that these massive carbon stocks will play in a climate increasingly perturbed by anthropogenic greenhouse gases remains uncertain, however. Long-term carbon exchange behavior of these systems requires many years of observation, and basic understanding of peatland carbon cycling response to climate over decadal or longer periods remains poor. This doctoral dissertation research project will apply paleoecological tools to investigate Siberian peatland ecosystem response to past climatic changes. The West Siberian Lowland contains the world's highest density of peat carbon, yet is poorly studied relative to Fennoscandian, European, and North American peat deposits. This research will use information in identifiable plant remains, soil carbon characteristics, and 14-C AMS age determinations of peat from a wide collection of cores to investigate spatiotemporal patterns of carbon dynamics in West Siberian peatlands. Specifically, the project will (1) determine the spatiotemporal nature of major ecological changes in peatland history important to Holocene peatland-atmosphere methane exchange, (2) determine how Holocene peat accumulation rates have been affected by these changes, and (3) assess recent patterns of C accumulation in the WSL towards increased understanding of their sensitivity to modern warming.
Terrestrial Northern Hemisphere ecosystems have been identified as globally critical carbon sinks for excess anthropogenic carbon dioxide, however, the year-to-year strength of this important sink is variable. The greatest terrestrial concentration of sequestered carbon is stored in peats within the continental interiors of North America and Eurasia. Study of the West Siberian Lowland is crucial to the assessment of the role of northern high-latitude environments in the global carbon cycle owing to the relative paucity of historical carbon accumulation studies in the region, the massive carbon stocks present here, and its location at the focus of recent 1-degree Celsius to 2-degrees Celsius per decade Arctic warming. Previous NSF-funded Russian-American collaborative research has resulted in the highest quality peat carbon inventory to date as well as an unprecedented collection of hard-to-get peat records from the remote West Siberian Lowland. These initial studies have identified a large spatial gap in record coverage that is coincident with the maximum latitudinal storage of peat carbon in the south of the region. This Doctoral Dissertation Research Improvement award will allow a final field campaign to Siberia, and completion of laboratory analyses. A complete picture of West Siberian Lowland carbon accumulation history can only be conclusively developed when this gap is filled. This award also will provide support to enable a promising student to establish a strong independent research career.
