Fire and ecosystem change in the Arctic across the Paleocene-Eocene Thermal Maximum

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Author(s): Denis, Elizabeth H.; Pedentchouk, Nikolai; Schouten, Stefan; Pagani, Mark; Freeman, Katherine H.
Author Affiliation(s): Primary:
Pennsylvania State University, University Park, PA, United States
University of East Anglia, United Kingdom
Royal Netherlands Institute for Sea Research, Netherlands
Yale University, United States
Volume Title: AGU 2016 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2016; American Geophysical Union 2016 fall meeting, San Francisco, CA, Dec. 12-16, 2016. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: Fire, an important component of ecosystems at a range of spatial and temporal scales, affects vegetation distribution, the carbon cycle, and climate. In turn, climate influences fuel composition (e.g., amount and type of vegetation), fuel availability (e.g., vegetation that can burn based on precipitation and temperature), and ignition sources (e.g., lightning). Climate studies predict increased wildfire activity in future decades, but mechanisms that control the relationship between climate and fire are complex. Reconstructing environmental conditions during past warming events (e.g., the Paleocene-Eocene Thermal Maximum (PETM)) will help elucidate climate-vegetation-fire relationships that are expressed over long durations (1,000-10,000 yrs). The abrupt global warming during the PETM dramatically altered vegetation and hydrologic patterns, and, possibly, fire occurrence. To investigate coincident changes in climate, vegetation, and fire occurrence, we studied biomarkers, including polycyclic aromatic hydrocarbons (PAHs), terpenoids, and alkanes from the PETM interval at IODP site 302 (the Lomonosov Ridge) in the Arctic Ocean. Both pollen and biomarker records indicate angiosperms abundance increased during the PETM relative to gymnosperms, reflecting a significant ecological shift to angiosperm-dominated vegetation. PAH abundances increased relative to plant biomarkers throughout the PETM, which suggests PAH production increased relative to plant productivity. Increased PAH production associated with the angiosperm vegetation shift indicates a greater prevalence of more fire-prone species. A time lag between increased moisture transport (based on published δD of n-alkanes data) to the Arctic and increased angiosperms and PAH production suggests wetter conditions, followed by increased air temperatures, favored angiosperms and combined to enhance fire occurrence.
Year of Publication: 2016
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Arctic Coring EXpedition; Arctic Ocean; Cenozoic; Expedition 302; Integrated Ocean Drilling Program; Lomonosov Ridge; Paleocene-Eocene Thermal Maximum; Paleoclimatology; Paleoenvironment; Paleogene; Tertiary
Coordinates: N875100 N875600 E1393300 E1361000
Record ID: 2018008346
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