A Laser-Based Optical Filtering System to Analyze Samples of Diatom Communities

Biomonitoring systems designed to protect the integrity of aquatic ecosystems must satisfy two complementary requirements if they are to be used in a successful management program. First, they must generate reliable information with respect to the current biological status of the ecosystem; second, they must be capable of reducing the lag time in the feedback of this information. This paper describes a biomonitoring system, currently being developed, that employs coherent optical spatial filtering techniques to rapidly identify diatoms and process species-abundance information. Preliminary results indicate that the optical problems associated with such a system can be overcome satisfactorily, although investigations are continuing into the problem of interfacing a microscope directly to the optical system. We envision that this system can eventually be employed in a management program along with chemical and physical data to obtain full beneficial use of the ecosystem without damage.