SS2.01 Effects of Biotic Interactions on the Structure and Function of Microbial Food Webs
Date: Wednesday, June 12, 2002
Location: Poster Session - VCC
 
BeardsleyC, Max-Planck-Institute for Marine Microbiology, Bremen, Germany, cbeardsl@mpi-bremen.de
Pernthaler, J, , Max-Planck-Institute for Marine Microbiology, Bremen, Germany, jperntha@mpi-bremen.de
 
IDENTIFICATION OF FREE-LIVING HETEROTROPHIC FLAGELLATES BY FLUORESCENCE IN SITU HYBRIDIZATION
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Free-living pelagic flagellates are a functionally diverse group of small protists, which occupy different niches in microbial food webs. Flagellates are a polyphyletic group and autotrophy has evolved independently several times, leading to co-existing modes of trophy in closely related species. Presently their identification is based on morphological features derived from electron microscopy and on live observations by light microscopy. For ecological purposes an identification scheme would be required that allows for a rapid quantification of different flagellate groups and also retains the possibility for functional classification into autotrophs and heterotrophs. We designed a oligonucleotide probe targeted to the SSU-rRNA of a monophyletic flagellate lineage and established specific conditions for fluorescence in situ hybridization. A protocol was developed that permits detection and quantification of small eucaryotes with low ribosome content in coastal marine plankton, and at the same time preserves chlorophyll fluorescence. Thus we could distinguish between auto-and heterotrophic members within the studied group in environmental samples.