The role of phytoplanktonic size fractions in the microbial food webs in two north Patagonian lakes (Argentina)

QUEIMALIÑOS, CP

VERH. INTERNAT. VEREIN LIMNOL.

E. Schweizerbart'sche Verlagsbuchhandlung

Lugar: Sttutgart; Año: 2002 vol. 28 p. 1236 - 1240

0368-0770

The different phytoplanktonic size fractions exhibit important interactions in the microbial food webs. In view of their significance, their role was analysed in two South Andean lakes (Argentina). The picoplankton, which together with the bacterioplankton constitute the prey for the mixotrophic and heterotrophic microorganisms, is dominant in both lakes, while the nanoplanktonic assemblage in these North Patagonian lakes is mainly constituted by flagellates. However, the microphytoplankton of the ultraoligotrophic Lake Moreno Oeste is largely constituted by dinoflagellates, while in Lake Morenito mixotrophic species of Dinobryon dominate. In order to determine grazing activities, short term feeding experiments were performed.