The toxic dinoflagellate Gymnodinium catenatum isolated from the southern coast of Korea was described under light and scanning electron microscopy, and its large subunit (LSU) rDNA was sequenced. In addition, the effects of temperature and salinity on its growth were investigated. The cells of G. catenatum, as viewed under the electronic microscope, were green-brown color, 38.1-77.4 μm in length and 26.1-40.8 μm in width. The epicone was conical, while the hypocone was trapezoidal. The nucleus was located at the central part of the cell. The apical groove was horseshoe-shaped and small pores were irregularly distributed on the cell surface. Molecular phylogeny based on LSU rDNA gene sequences showed that the Korean G. catenatum and previously reported species formed a monophyletic clade within Gymnodinium sensu stricto clade. The maximum growth rate of 0.37 day-1, was obtained at 25°C and 35 psu, and the maximum cell density of 1,073 cells mL-1, was observed at 20°C and 25 psu. However, G. catenatum did not grow at temperature <15°C and <30°C. These results suggest that environmental conditions of summer and autumn in the southern coast of Korea may be favorable for the growth of G. catenatum.

질산염과 인산염의 농도가 다른 배지에서 Gymnodinium sanguineum과 Sketetonema costotum의 성장과 세포구성성분을 비교 분석하였다. 질산염은 0, 0.3, 0.6, 0.9, 1.2 mM, 인산염은 0, 15, 30, 45, 60μM을 각각 첨가한 배지에서 배양하였을 때, 저농도의 질산염 및 인산염 배지에서 G. sanguineum의 성장은 억제되었으나, S. costatum은 성장에 영향을 받지 않은 것으로 나타났다.