A Mechanism of Red Tide Formation. I. Growth Rate Estimate by DCMU-Induced Flourescence Increase

Abstract

Growth experiments with unialgal cultures of 'red tide' flagellates Prorocentrum triestinum and Olisthodiscus luteus showed that relative growth rates of phytoplankton can be estimated from DCMU-~nduced fluorescence increase (DCMU-FI). This method was applied to the estimation of relative growth rate of a natural population in Tanigawa Harbor (Japan) where 0. luteus was dominant throughout the experiment. Measurements were made three times a day over a week. A steady increase of photosynthetic capacity indicated by DCMU-F1 was followed by a red t ~ d e of 0. luteus. Such increase of photosynthetic capacity was associated with accumulation of ammonia and low dissolved oxygen levels in the water colunln near the bottom.