거제도 장목항에서 적조원인생물 Akashiwo sanguinea (Dinophyceae): 형태, 분자계통학적 특성 및 온도와 염분에 따른 성장 특성

Abstract

The morphological characteristics of the bloom-forming dinoflagellate Akashiwo sanguinea isolated from Jangmok Harbour, Geoje in Korea was examined using light and scanning electron microscope (SEM), and its large subunit (LSU) rDNA was sequenced. Additionally, investigation was done on the effects of temperature and salinity on the growth of A. sanguinea. The cells were dorso-ventrally compressed up to 54.7-70.3 μm long and 31.5-48.5 μm wide. The epicone was conical while the hypocone was separated into two lobes. The nucleus was positioned at the center of the cell. The yellow-brown chloroplasts radiated close to the cell center. SEM observation indicated that A. sanguinea has an e-shaped apical groove. Molecular phylogeny based on LSU rDNA gene sequences revealed that the A. sanguinea strains isolated from Jangmok Harbor were classified in the clade of ribotype A. The maximum growth rate (0.50 day-1) was observed at 20°C and 20 psu, while the maximum cell density (1,372 cells mL-1) was observed at 25°C and 30 psu. This indicates that the blooms of A. sanguinea ribotype A in Korean coastal area are affected by water temperature, rather than the salinity.