Effects of temperature and salinity on the growth of four harmful red tide flagellates occurring in Isahaya Bay in Ariake Sound, Japan.

摘要

Three harmful red tide causative raphidophytes Chattonella antiqua, Chattonella marina and Heterosigma akashiwo, and a dinoflagellate, Cochlodinium polykrikoides, were isolated from Isahaya Bay, Japan in 2003 and 2004. The growth characteristics of these 4 clonal cultures were examined in 60 different temperature (10-32.5 degrees C) and salinity combinations (16-36) under a light intensity of 80 micro mol/m2/s. Chattonella antiqua reproduced at 15-32.5 degrees C and 16-36 PSU, and the maximum growth rate was 0.99/day at 30 degrees C and 32 PSU. Chattonella marina reproduced at 12.5-32.5 degrees C and 16-36 PSU. The maximum growth rate was 0.83/day, which was obtained at 30 degrees C and 24 PSU. H. akashiwo reproduced at 10-32.5 degrees C and 16-36 PSU. The maximum growth rate was 1.14/day at 25 degrees C and 24 PSU. Cochlodinium polykrikoides reproduced at 10-32.5 degrees C and 16-36 PSU. The maximum growth rate was 0.56/day at 27.5 degrees C and 32 PSU. The 4 red tide flagellates examined in this study appeared to be euryhaline. The optimum temperatures for maximum growth were different in each species and these conditions clearly corresponded with recent red tide occurrences in Isahaya Bay. Compared to the growth conditions previously reported, these 4 isolates from Isahaya Bay are likely to tolerate relatively higher temperatures..