RECENT APPLICATIONS OF FLOW-CYTOMETRY IN AQUATIC MICROBIAL ECOLOGY

Microorganisms (unicellular algae, bacteria) constitute fundamental co mpartments of aquatic ecosystems because of their high concentrations and activities. The evaluation and understanding of their behaviour an d role raise different problems for which traditional methodologies ar e often inadequate, whether they refer to global or classical microsco pic analyses. Flow cytometry (FCM) has been recently used to study mic roorganisms in aquatic environments. Although this technology is still applied on a limited scale in our field, a large number of works has been done showing that FCM seems to be a promising tool for aquatic mi crobial ecology. This paper summarizes, from the literature produced d uring the last decade and with original data obtained in our laborator y, the main questions related to the cell identification, the evaluati on of cell viability, biomasses and productions and the measurements o f bacterial and phytoplanktonic activities. The representativeness of sampling and observation scales is also discussed within the framework of the FCM measurements.