Selective control of marine algal species by electrolysis treatment.
SAMAN WIJESEKARA. R.G, NAKAO NOMURA AND MASATOSHI MATSUMURA
This paper deals with the application of electrolysis technology for the selective control of marine algal species. The sensitivity of different marine algal species to electrolysis may be different due to their size and structural differences. Electrolysis experiments were conducted using four algal species, namely Chlorella spp., Chaetoceros spp., Isochrysis spp. and Tetraselmis spp. Batch and continuous runs were conducted from 0-7 minutes and 0-80 minutes, respectively. Drastic depletion of algal cell number was not observed during batch electrolysis. However, fluorescein diacetate and propidium iodide staining showed significant algal mortality. Different sensitivities were also observed for similar electrolysis conditions. Continuous electrolysis data revealed almost no survival for Chlorella spp. at 80 minute electrolysis time while survival for Isochrysis spp. was around 60% at similar conditions. Results indicated that the green algae Chlorella spp. is the most sensitive while the brown algae Isochrysis spp. is the most resistant among the four species studied. More importantly, this confirmed that the beneficial marine algae Isochrysis spp. can be allowed to dominate by selectively limiting the growth of three other algal species tested in this work through electrolysis treatment.