Bacterial activity in soils of a sub-antarctic island

Heterotrophic bacterial activities in the soils from five habitats on sub-Antarctic Marion Island (46°54'S, 37°45'E) were estimated by a kinetic method for glucose mineralization and by a dehydrogenase assay. The dehydrogenase assay yielded more reproducible activity estimates than did the glucose mineralization method. However, the two methods resulted in fairly similar inter-site patterns of relative activities. On a specific activity basis (i.e. activity per bacterial cell) values by the glucose mineralization procedure decreased across sites in the order albatross nest site > medium-altitude fjaeldmark > low-altitude fjaeldmark > fernbrake > mire. Based on dehydrogenase activity the order was albatross nest site > fernbrake > medium-altitude fjaeldmark > low-altitude fjaeldmark > mire. These patterns are discussed in the context of information on the numbers, biovolumes, morphologies and fluroescence characteristics of the bacteria at the various sites.