JOURNAL OF PLANKTON RESEARCH | VOLUME 26 | NUMBER 1 | PAGES 61-66 | 2004
© Oxford University Press 2004; all rights reserved
Effects of temperature, salinity and irradiance on the growth of the harmful red tide dinoflagellate Cochlodinium polykrikoides Margalef (Dinophyceae)
Laboratory of Fisheries Bioenvironmental Science, Division of Bioresource and Bioenvironmental Sciences, Kyushu University, Hakozaki, Fukuoka 812-8581, 1 Harmful Algal Blooms Division, National Research Institute of Fisheries And Environment of Inland Sea, Ohno, Saeki, Hiroshima 739-04, Japan and 2 Department of Ocean Environment System Program, Yosu National University, Dun-Deok, Yosu, 550-749, Korea
* Corresponding Author: dikim{at}agr.kyushu-u.ac.jp
The effects of temperature, salinity and irradiance on the growth of the harmful red tide dinoflagellate Cochlodinium polykrikoides were examined in the laboratory. From 60 different combinations of temperature (10–30°C) and salinity (10–40) under saturated irradiance, C. polykrikoides exhibited its maximum specific growth rate of 0.41 day-1 at a combination of 25°C and salinity of 34. Optimum growth rates of >0.3 day-1 were observed at temperatures ranging from 21 to 26°C and at salinities from 30 to 36. The organism did not grow at temperatures 
10°C and only grew at salinities >30 if the temperature was >15°C. It was able to grow in temperatures ranging from 15 to 30°C and at salinities from 20 to 36. These values closely resembled those observed for this species in situ. It appears as if C. polykrikoides is a stenohaline organism that prefers high salinities, indicative of offshore waters. Temperature had the greatest influence on the growth rate, followed by salinity, and then the interaction between temperature and salinity. The optimum irradiance for growth was >90 µmol m-2 s-1. Photoinhibition did not occur at 230 µmol m-2 s-1, which was the maximum irradiance used in this study.