TEMPORAL ABUNDANCE OF NAKED BACTERIVORE AMEBAS IN COASTAL EAST ANTARCTICA

The densities of naked amoebae in the water column of two coastal site s off Eastern Antarctica were sampled throughout 1993. A few samples w ere also collected from nearby Ellis Fjord. This is the first study to detail abundances of bacterivore amoebae in Antarctic coastal waters. Overall numbers in the water column were highly variable (below detec tion to 2000 amoebae l(-1)) and showed no clear seasonal trends. The h igh scatter in the data is believed to reflect patchiness within the w ater column; amoebae are predominantly floc-associated. Highest abunda nces, up to 2626 amoebae l(-1), were recorded at the ice-water interfa ce. The majority of amoebae isolated throughout the year were flattene d, fan-shaped vannellids and platyamoebae. Small morphotypes (less tha n 10 mu m long) were occasionally abundant, comprising up to 45% of th e total count. Despite the relatively constant population of amoebae i n these coastal waters, their contribution to the total carbon pool of microbial plankton was less than 1%. (C) 1998 Academic Press Limited.