PARENT SESSION
Oral Session #25: Soil Ecology: Microbial and Invertebrate. Presiding: W. Parsons.
Tuesday, August 7, 2001. 8:00 AM to 12:00 PM. Hall of Ideas G.
Invertebrates in frozen systems: the cryoconite holes of the Antarctic Dry Valleys.
PORAZINSKA, DOROTA1, FOUNTAIN, ANDREW2, MUELLER, DEREK3, NYLEN, THOMAS2, VIRGINIA, ROSS4, WALL, DIANA1, 1 2 3 4
ABSTRACT- Invertebrates occur in cryconite holes (isolated water pockets found beneath the ice surface) in the Arctic and Antarctic ice shelves, but their presence, abundance, and distribution have not been investigated in glaciers. In the Antarctic Dry Valley landscape, glaciers are important sources of water to the bare soils, ice-covered lakes, and meltstreams. We examined Canada glacier in the MCM LTER Taylor Valley ecosystem as a habitat for invertebrates. We sampled (with a SIPRE ice corer) 55 cryoconite holes from 8 spatially separated locations on Canada Glacier. Dimensions, water chemistry, sediment, and invertebrate abundance were collected for each cryoconite hole. Tardigrades(overall mean = 1029/ice core) and rotifers (overall mean = 1411/ice core) were abundant in most (75% and 91%) of cryoconite holes. Nematodes, the dominant invertebrate group in soils, were not found. Cryoconite holes from the Upper and East parts of Canada glacier were smaller (by 10 - 30%), contained less sediment (20 - 40%), and supported smaller (by ~50%) populations of invertebrates than cryoconite holes from the Lower and West parts of the glacier. Similar trends were observed for acidity and salinity. We hypothesize that presence and abundance of invertebrates, and the distribution of cryoconite holes suitable for invertebrates are determined by the wind direction, aeolian material transfer (soil particles and invertebrates), aspect, and the abundance of invertebrates in the surrounding soil, lakes, and stream environments.
KEY WORDS: cryoconite holes, extreme environment, glaciers, ice