HR: 15:25h
AN: C23B-08    [Abstracts]
TI: Monitoring Snow on ice as Critical Habitat for Ringed Seals
AU: * Kelly, B P
EM: bkelly@nsf.gov
AF: Office of Polar Programs, National Science Foundation, 4201 Wilson Blvd. Suite 755, Arlington, VA 22230, United States
AU: Moran, J
EM: john.moran@noaa.gov
AF: Ted Stevens Marine Research Institute, NOAA, 17109 Pt Lena Loop Rd, Juneau, AK 99801, United States
AU: Douglas, D C
EM: david_douglas@usgs.gov
AF: USGS Alaska Science Center, Juneau Office, 3100 National Park Rd., Juneau, AK 99801, United States
AU: Nghiem, S V
EM: Son.V.Nghiem@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, MS 300-235, Pasadena, CA 91109, United States
AB: Ringed seals are the primary prey of polar bears, and they are found in all seasonally ice covered seas of the northern hemisphere as well as in several freshwater lakes. The presence of snow covered sea ice is essential for successful ringed seal reproduction. Ringed seals abrade holes in the ice allowing them to surface and breathe under the snow cover. Where snow accumulates to sufficient depths, ringed seals excavate subnivean lairs above breathing holes. They rest, give birth, and nurse their young in those lairs. Temperatures within the lairs remain within a few degrees of freezing, well within the zone of thermal neutrality for newborn ringed seals, even at ambient temperatures of -30° C. High rates of seal mortality have been recorded when early snow melt caused lairs to collapse exposing newborn seals to predators and to subsequent extreme cold events. As melt onset dates come earlier in the Arctic Ocean, ringed seal populations (and the polar bears that depend upon them) will be increasingly challenged. We determined dates of lair abandonment by ringed seals fitted with radio transmitters in the Beaufort Sea (n = 60). We compared abandonment dates to melt onset dates measured in the field, as well as estimated dates derived from active (Ku-band backscatter) and passive (SSM/I) microwave satellite imagery. Date of snow melt significantly improved models of environmental influences on the timing of lair abandonment. We used an algorithm based on multi-channel means and variances of passive microwave data to detect melt onset dates. Those melt onset dates predicted the date of lair abandonment ± 3 days (r ² = 0.982, p = 0.001). The predictive power of passive microwave proxies combined with their historical record suggest they could serve to monitor critical changes to ringed seal habitat.
DE: 0456 Life in extreme environments
DE: 0480 Remote sensing
DE: 0736 Snow (1827, 1863)
DE: 0740 Snowmelt
SC: Cryosphere [C]
MN: 2007 Fall Meeting