Antarctic Science

Biological Sciences

Microbial biomass and community structure changes along a soil development chronosequence near Lake Wellman, southern Victoria Land

Jackie Aislabiea1 c1, James Bockheima2, Malcolm Mcleoda1, David Huntera1, Bryan Stevensona1 and Gary M. Barkera2

a1 Landcare Research, Private Bag 3127, Hamilton, New Zealand

a2 Department of Soil Sciences, University of Wisconsin, Madison, WI 53706-1299, USA


Four pedons on each of four drift sheets in the Lake Wellman area of the Darwin Mountains were sampled for chemical and microbial analyses. The four drifts, Hatherton, Britannia, Danum, and Isca, ranged from early Holocene (10 ka) to mid-Quaternary (c. 900 ka). The soil properties of weathering stage, salt stage, and depths of staining, visible salts, ghosts, and coherence increase with drift age. The landforms contain primarily high-centred polygons with windblown snow in the troughs. The soils are dominantly complexes of Typic Haplorthels and Typic Haploturbels. The soils were dry and alkaline with low levels of organic carbon, nitrogen and phosphorus. Electrical conductivity was high accompanied by high levels of water soluble anions and cations (especially calcium and sulphate in older soils). Soil microbial biomass, measured as phospholipid fatty acids, and numbers of culturable heterotrophic microbes, were low, with highest levels detected in less developed soils from the Hatherton drift. The microbial community structure of the Hatherton soil also differed from that of the Britannia, Danum and Isca soils. Ordination revealed the soil microbial community structure was influenced by soil development and organic carbon.

(Received June 20 2011)

(Accepted September 27 2011)

(Online publication December 15 2011)