Ref ID : 1055
G.R. Hawthorn and J.C. Ellis-Evans; Benthic protozoa from maritime antractic freshwater lakes and pools. Br.Antarct.Surv.Bull. 62:67-81, 1984
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Eighty-two species of benthic Protozoa (33 flagellates, 15 rhizopods, 4 heliozoans and 30 ciliates) have been isolated from a variety of Maritime Antarctic freshwater lakes and pools. Of these, 43 species were new records from Antarctica. All the Protozoa were cosmopolitan and, with few exceptions, of small size (under 150 µm). Flagellates and ciliates showed the greatest species diversity but flagellates and amoebae dominated numerically. Cluster analysis identified differences in species composition between lake populations and pool populations. However, despite the wide range of trophic status evident within the two groups of systems, population composition was remarkably similar within each group. Seasonal fluctuations, both in major groups (flagellates and rhizopod amoebae) and individual species, were linked with fluctuations in numbers and activity of algae and bacteria. A large proportion of the rhizopod population was always encysted whereas flagellate cysts normally constituted less than 5% of the total population. It is concluded that flagellates are the most important protozoan group in these polar freshwater systems and constitute a potentially substantial grazing component.