Minimal influence of water and nutrient content on the bacterial community composition of a maritime Antarctic soil.

Bacterial community composition was determined by culture-independent PCR-based methods in two soils differing markedly in their water, C, N and P contents sampled from Mars Oasis on Alexander Island, western Antarctic Peninsula. 16S rRNA sequences of the phyla Actinobacteria, Cyanobacteria, α-Proteobacteria and Acidobacteria were commonly (> 8% frequency) obtained from soil. Those of β-, γ- and δ-Proteobacteria, Chloroflexi, Bacteroidetes, Verrucomicrobia, Planctomycetes, Gemmatimonadetes and Firmicutes were less frequent. Comparisons of slopes of collector's curves and the Shannon-Weiner diversity index indicated no difference in overall bacterial diversity between the two soils, although sequences of δ-Proteobacteria and the cyanobacterial genus Leptolyngbya were more commonly derived from the soil with the higher water and nutrient content. The data suggest that different levels of soil water, C, N and P have only a minor effect on the bacterial community composition of maritime Antarctic soils.