Studies on B group vitamin requirements of red tide phytoplankton. III. Physiological ecology of Chattonella antiqua (HADA) ONO on B group vitamin requirements.

Abstract

Physiological characteristics of the growth of two strains of Chattonella antiqua (HADA) ONO (Raphidophyceae), haarmful red tide phytoplankters, were examined in axenic clonal cultures with special reference to B group vitamin requirements. C. antiqua Harima-77 and TSU-8011 preferred a relatively high concentration of nutrients, and required essentially vitamin B12 among the B group vitamins for their growth. It was found that their growth rates and final cell yields were dependent on the vitamin B12 concentrations in the media. The half-saturation constant of vitamin. B12 for each strain was small:0.05ng/l for Harima-77 and 0.35ng/l for TSU-8011. The amount of vitamin B12 required to maximize final cell yields was around 10ng/l for Harima-77 and 20ng/l for TSU-8011. The maximum specific growth rate of each strain was 0.69 and 0.48 day-1, respectively. The minimum cell quota of vitamin B12 was estimated at 4.7×10-4pg/cell or 11.7 molecules/μm3 of cell for Harima-77 and 1.6×10-3pg/cell or 27.5 molecules/μm3 of cell for TSU-8011. These results suggest that vitamin B12 in seawater may be one of the principal factors con-trolling the growth of C. antiqua, and that the amount of the vitamin required to maximize both growth rates and growth yields is around 10 or 20ng/l.