HR: 17:15h
AN: C24A-06 [Abstracts]
TI: Small-scale Patterned Ground in the Arctic: Maps of Vegetation and Thaw Depth on a North-South
Transect
AU: * Raynolds, M K
EM: fnmkr@uaf.edu
AF: Institute of Arctic Biology, University of Alaska Fairbanks, 311 Irving
P.O. Box 757000, Fairbanks, AK 99775
United States
AU: Walker, D A
EM: ffdaw@uaf.edu
AF: Institute of Arctic Biology, University of Alaska Fairbanks, 311 Irving
P.O. Box 757000, Fairbanks, AK 99775
United States
AU: Kade, A N
EM: anja_kade@yahoo.com
AF: Institute of Arctic Biology, University of Alaska Fairbanks, 311 Irving
P.O. Box 757000, Fairbanks, AK 99775
United States
AU: Munger, C A
EM: fncam1@uaf.edu
AF: Institute of Arctic Biology, University of Alaska Fairbanks, 311 Irving
P.O. Box 757000, Fairbanks, AK 99775
United States
AB:
A set of 10 x 10 m grids were examined at 10 sites along an Arctic transect from treeline in the south to the coldest part of
the Canadian Arctic Islands. Six of the sites are on the Alaska North Slope, one near Inuvik on the Mackenzie River Delta,
and three on Canadian Arctic Islands: Banks, Prince Patrick, and Ellef Ringnes. At half the sites additional grids were
established to represent common moisture regimes. Vegetation maps are presented for 5 x 5 m portions of all the grids, and
also for 1 x 1 m portions for the most northern grids with smaller-scale patterning. Vegetation patterns, caused by
cracking, cryoturbation and frost-heave are evident. All the grids are underlain by permafrost, and have active layers of
annually thawed soil. Thaw depth maps are presented for all grids, interpolated from measurements at 0.5 m intervals. The
scale of vegetation patterning decreases with latitude from approximately 3 m to 0.5 m diameter. The amount of bare ground
increases from north to south, from <1% to >50% (zonal sites). Thaw depth reflects the vegetation patterns, ranging
from <10 cm to >80 cm, with less thaw in areas with thick, insulating vegetation. This relationship results in a
counter-intuitive effect - the shallowest thaw depths were found in the most southern plots where the vegetation, especially
moss, is thickest (live and dead moss thickness > 15 cm).
DE: 0704 Seasonally frozen ground
DE: 0706 Active layer
DE: 0718 Tundra (9315)
SC: Cryosphere [C]
MN: Fall Meeting 2005