Biological activity as influenced by microtopography in a Cryosolic soil, Baffin Island, Canada

Biological activity and cellulose decomposition in the topsoil of an east-w est oriented slope in the Canadian Arctic were studied in the summers of 19 95 and 1996. Two microsites, small mounds and the adjacent troughs, charact erize the surface of the study site on a slope. This microtopography result s from erosion in the past when the area was not vegetated, and recent fros t action. The aim of the study was to describe differences in the decomposi tion processes and the contributing factors in relation to the microtopogra phy. Biological activity in the soil was measured by the feeding activity o f the soil organisms. In both years of the study feeding activity by bait-l amina test and cellulose decomposition by nylon-mesh-bag assessment were hi gher in the troughs than in the mounds. The C/N ratios and acidity were sim ilar in the zone showing the highest biological activity at both sites, but soil temperatures and water content were different. Soil moisture was foun d to be the main factor affecting feeding activity and cellulose decomposit ion at both microsites. Copyright (C) 1999 John Wiley & Sons, Ltd.