Vertical microzonation of ciliates in cryoconite holes in Ecology Glacier, King George Island

There are hardly any data concerning the vertical micro−distribution of protozoa in water column in cryoconite holes on the glacier surface. Such comparisons can provide in− sights into the ecology of protozoa. The present research wasmade on Ecology Glacier (South Shetland Islands, Antarctic); vertical microzonation of ciliates in relation to physical and chemical parameters in cryoconite holes was studied. The density and biomass of protozoans significantly differed between the studied stations (cryoconite holes), with the lowest num− bers in the surface water and the highest in the bottom water. The surface waters were domi− nated by mixotrophic and omnivorous taxa,whereas the deepest sampling level has shown the increase of the proportion of bacterivore species. Ordination analysis indicated that TN and P−PO4 can strongly regulate the abundance and species composition of protozoa. The redun− dancy analyses (RDA) showed that the ciliate communities can be separated into two groups. The first group included species associated with surface water: Halteria grandinella and Codonella sp. The second group included species that are associated with bottom water: Prorodon sp., Holosticha pullaster, Stylonychia mytilus−complex and small scuticociliates.