ABSTRACT: The seasonal and vertical abundances of ciliates and flagellates are described over a 2 yr period in Lake Kinneret, Israel, a warm meso-eutrophic monomictic lake. Ciliate numbers ranged from 3 to 47 cells ml^-1. At the thermocline and oxycline region, the highest ciliate numbers were observed in autumn, with Coleps hirtus as the dominant species. Maximum heterotrophic nanoflagellate abundance (1300 cells ml^-1) was found in the epilimnion in winter-spring, minimum numbers (66 cells ml^-1) occurred in autumn. Bacteria ranged from 10⁵ to 3.10⁷ cells ml^-1 with highest numbers at the decline of the Peridinium gatunense bloom and the lowest during winter. Protozoa, especially ciliates, appeared to be important food sources for metazooplankton. Top-down control is an important factor determining the structure of the microbial loop in Lake Kinneret.

KEY WORDS: HNAN · Ciliates · Bacteria · Lake Kinneret

Published in AME Vol. 14, No. 2 (1998) on February 13
Print ISSN: 0948-3055; Online ISSN: 1616-1564. Copyright © Inter-Research, Oldendorf/Luhe, 1998