Assessment of new algicide thiazolidinedione (TD49) for the control of marine red tide organisms

Abstract

Worldwide development of harmful algal blooms causes serious problem for public health and fisheries industries. To evaluate the algicidal impact on the harmful algae bloom species in aquatic ecosystems of coast, a new algicide thiazolidinedione derivative (TD 49) were tentatively examined in the growth stages (i.e., lag, logarithmic and stationary phase) of rapidophyceae Heterosigma akashiwo, Chattonella marina and Chattonella sp.. Three strains could easily destroy in the lag phase due to relatively weak cell walls than those of the logarithmic and stationary phase. It is thought that inoculation of TD 49 substances into initial or developmental natural blooms with a threshold concentration (2 μM) can maximize the algicidal activity. Also, bio-chemical assays revealed that the algicidal substances from all culture strains were likely to be extracellular substances because those cells have easily destroyed in cell walls. On the other hand, natural zooplankton communities were influenced within the exposure experiments of 2 μM, which is showed the maximum algcidal activity of tested organisms. These results indicate that although the TD 49 substance is potential agents for the control of H. akashiwo, C. marina and Chattonella sp. in the enclosed eutrophic bay and coastal water, more detailed research of acute toxicity effect on high trophic organism in marine ecosystems need to be co