HR: 0800h
AN: PP41A-0178    [Abstracts]
TI: Reconstruction of Centennial and Millennial-scale Climate and Environmental Variability during the Holocene in the Central Canadian Arctic
AU: * Rolland, N
EM: rolland.4@osu.edu
AF: The Ohio State University Nicolas Rolland, David Porinchu, Department of Geography 1036 Derby Hall 154 North Oval Mall, Columbus, OH 43210, United States
AU: Porinchu, D
EM: porinchu.1@osu.edu
AF: The Ohio State University Nicolas Rolland, David Porinchu, Department of Geography 1036 Derby Hall 154 North Oval Mall, Columbus, OH 43210, United States
AU: MacDonald, G
EM: macdonal@geog.ucla.edu
AF: UCLA Glen M. MacDonald, Department of Geography 1125 Bunche Hall, Los Angeles, CA 90095, United States
AU: Moser, K
EM: kmoser@uwo.ca
AF: University of Western Ontario Katrina A. Moser, Department of Geography Social Science Building 1151 Richmond Street North, London, ON N6A 5C2, Canada
AB: The Arctic and sub-Arctic regions are experiencing dramatic changes in surface temperature, sea-ice extent, glacial melt, river discharge, soil carbon storage and snow cover. According to the IPCC high latitude regions are expected to warm between 4^oC and 7^oC over the next 100 years. The magnitude of warming and the rate at which it occurs will dwarf any previous warming episodes experienced by latitude regions over the last 11,000 years. It is critical that we improve our understanding of how the Arctic and sub-Arctic regions responded to past periods of warming, especially in light of the changes these regions will be experiencing over the next 100 years. One of the lines of evidence increasingly utilized in multi-proxy paleolimnological research is the Chironomidae (Insecta: Diptera). Also known as non-biting midge flies, chironomids are ubiquitous, frequently the most abundant insects found in freshwater ecosystems and very sensitive to environmental conditions. This research uses Chironomidae to quantitatively characterize climate and environmental conditions of the continental interior of Arctic Canada during the Holocene. Spanning four major vegetation zones (boreal forest, forest-tundra, birch tundra and herb tundra), the surface samples of 80 lakes recovered from the central Canadian Arctic were used to assess the relationship of 22 environmental variables with the chironomid distribution. Redundancy analysis (RDA) identified four variables, total Kjeldahl nitrogen (TKN), pH, summer surface water temperature (SSWT) and depth, which best explain the variance in the distribution of chironomids within these ecoregions. In order to provide new quantitative estimates of SSWT, a 1-component weighted average partial least square (WA-PLS) model was developed (r²jack = 0.76, RMSEP = 1.42^oC) and applied downcore in two low arctic continental Nunavut lakes located approximately 50 km and 200 km north of modern treeline. This robust midge-inferred temperature reconstruction of the Holocene thermal conditions will then be compared with previous research describing vegetation development in this region. This study provides new and important data which helps to further resolve millennial and centennial-scale climate variability in the central Canadian Arctic during the Holocene.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1637 Regional climate change
DE: 4914 Continental climate records
DE: 4942 Limnology (0458, 1845, 4239)
DE: 4950 Paleoecology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting