Prokaryote diversity in Antarctic soils and sediments

Prokaryotes community structures of eight distinct sites around Casey Station, Antarctica were investigated by denaturing gradient gel electrophoresis (DGGE) of amplified 16S rDNA fragments. Twelve different bacterial sequences were successfully obtained from excised DGGE bands. Nine sequences belong to the phylum Bacteriodetes, two are related to Proteobacteria and one is affiliated to Gemmatimonadetes. The bacterial DGGE profiles were transferred into presence/absence matrix to test for similarity between sites.

Comparison of community structure based on non-metric multidimensional scaling plots (nMDS) suggested that bacterial diversity in the protected areas, ASPA 135 (mossy area) and ASPA 136 (penquin rookery), are similar to one another but are distinct from that found in Browning Peninsula. On the other hand, highly impacted sites such as Thalla Valley and Red Shed yielded lower bacterial diversity. A number of environmental variables including soil pH, carbon, nitrogen, and water content were also measured in order to correlate the environmental variables with the bacterial community. The results showed that pH might be the most significant factor in determining bacterial community structure.