THE AQUATIC TESTATE AMEBAS FAUNA OF THE STROMNESS BAY AREA, SOUTH-GEORGIA

Fortysix taxa of testate amoebae were found in 45 samples of aquatic environments ranging from small pools to lakes. Four assemblages were distinguished which, to some degree, can be related ecologically to different pH ranges, and to differences in the habitat structure. The Nebela collaris assemblage occurs in acid pools mostly vegetated with mosses. The Centropyxis gibba gibbosa-Euglypha tuberculata-Difflugia globularis/globulus assemblage is found in the sediments of circumneutral to slightly alkaline lakes. Both of the other assemblages are mainly found in pools, which are more (for the Trinema assemblage) or less vegetated with mosses, in slightly acid (the Difflugia penardi-Centropyxis aerophila assemblage) or circumneutral to slightly alkaline (the Trinema lineare assemblage) conditions. A generic comparison with the Arctic fauna indicates differences, especially in the role of Difflugia as a dominant genus in aquatic habitats.