HR: 0800h
AN: H21B-1333    [Abstracts]
TI: Controls on Soil Moisture Wicking Extent Away From Lake Fryxell (Constant Boundary Condition) in the Dry Valleys Polar Desert, Antarctica
AU: * Gooseff, M N
EM: mgooseff@mines.edu
AF: Colorado School of Mines, Dept. of Geology & Geological Engineering 1516 Illinois St., Golden, CO 80401 United States
AU: Barrett, J E
EM: john.e.barrett@dartmouth.edu
AF: Dartmouth College, Environmental Studies Program, Hanover, NH 03755 United States
AU: Hill, K R
EM: kenneth.hill@colorado.edu
AF: University of Colorado, Dept. of Geography, Boulder, CO 80322 United States
AU: Bate, D B
EM: d.bradley.bate@dartmouth.edu
AF: Dartmouth College, Environmental Studies Program, Hanover, NH 03755 United States
AU: Northcott, M L
EM: laurissa_lou@yahoo.com
AF: Colorado School of Mines, Dept. of Geology & Geological Engineering 1516 Illinois St., Golden, CO 80401 United States
AU: Northcott, M L
EM: laurissa_lou@yahoo.com
AF: University of Colorado, Dept. of Geography, Boulder, CO 80322 United States
AU: Zeglin, L H
EM: lzeglin@unm.edu
AF: University of New Mexico, Dept. of Biology, Albuquerque, NM 87131 United States
AU: Bobb, M
EM: bobbm@unm.edu
AF: University of New Mexico, Dept. of Biology, Albuquerque, NM 87131 United States
AU: Vesbach, C D
EM: cvesbach@unm.edu
AF: University of New Mexico, Dept. of Biology, Albuquerque, NM 87131 United States
AB: The extreme conditions of the Antarctic Dry Valleys, are accentuated by the lack of available water across the landscape. In general, the majority of soils are wetted only briefly after infrequent, small snowfall events. However, adjacent to glacial meltwater streams and closed-basin lakes, soils wick water from these sources and wetted fronts at the soil surface are visually conspicuous, extending several meters from shoreline. We postulate that this wicking of surface water is responsible for unique solute transport and microbial diversity within the Dry Valley landscape. We performed synoptic sampling and topographic surveys around Lake Fryxell, Taylor Valley, to quantify the influence of two geomorphic controls on the scaling of these wetting fronts: 1) near-shore topography (slope), and 2) soil grain size distribution. The topographic survey was carried out with a GPS RTK unit (>10,000 points), and in the synoptic sampling campaign we collected 120 samples (4 samples from wet to dry sediments at 30 transects around the lake) for gravimetric soil moisture and particle size analysis, and made measurements of surface soil moisture, depth to permafrost at an additional 114 transects. We found that wetted fronts range in distance from 1.4 to 22.2 m and depth to resistance of penetration (taken as depth of active layer) ranged from 12 to 63.5 cm, generally decreasing with distance from shore. Our results suggest that near-lake soils are fairly homogeneous in particle size distribution; therefore slope has a greater control on wicking front distance, explaining 54% of the variance as a power-law function.
UR: http://www.mines.edu/~mgooseff/web_antarctica/antarctic_proj.html
DE: 1845 Limnology (0458, 4239, 4942)
DE: 1865 Soils (0486)
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: Fall Meeting 2005