Detection of Toxic Phytoplankton Species by Immunochemical Particle Analysis Based on Flow Cytometry

Particulate suspended matter in oceanic, coastal, and estuarine regions can be specifically marked immunochemically with a fluorescent probe using antisera recognizing antigens present on their surface. Of the particulate matter, phytoplankton is a major component. Toxic species that may form harmful blooms can be a direct threat to aquaculturing, tourism, sea-life and man. In order to detect such species in natural fixed phytoplankton populations, immunochemical tagging has been combined with flow cytometric evaluation. Microalgal cells can be labeled with a fluorescent probe (fluorescein isothiocyanate, FITC, is recommended). Labeled cells are counted using a flow cytometer. This method has proved to be applicable in a monitoring programme in the North Sea.