Ecology of testate amoebae (Protists) in mosses: distribution and relation of species assemblages with environmental parameters (King George Island, Antarctica)

Abstract

Microbial communities living in mosses are known to constitute early indicators of ecosystem disturbances, but little is known about their response to environmental factors in the Antarctic area. This paper presents the first major study on testate amoebae from different species of mosses occurring on King George Island (Antarctica). The objective of the study was to investigate the structure and spatial distribution of moss-dwelling testate amoebae communities and to identify the environmental factors determining the structure of their assemblages. Additionally, we compared moss-dwelling testate amoebae communities on King George Island with other isolated islands of the Antarctic. Samples were collected from different species of mosses (Polytrichastrum alpinum, Sanionia georgico-uncinata, Sanionia uncinata, and Brachythecium austrosalebrosum). Sampling was carried out three times from 17 January to 24 February 2012. The species richness and abundance of protozoa differed significantly between the stations studied with the lowest count found in Polytrichastrum and the highest in Sanionia. The total population of testate amoebae was dominated by small taxa recognised as cosmopolitan, also recorded on other islands of the maritime Antarctic. The RDA analysis showed that all variables together accounted for 84.5 % of the total variance. However, variables that significantly explained the variance in testate amoebae communities were moisture, temperature, pH, and dissolved oxygen. Further research is required to explain the impact of biotic factors influencing the presence of testate amoebae, including the abundance of bacteria, microalgae, and small metazoa.