To clarify an unspecified marine sand-dwelling dinoflagellate isolated from samples collected at a sandy beach of Geoje Island, Korea, its morphology and molecular phylogeny based on the small (SSU) and partial large subunit (LSU) rRNA gene sequences were examined. In addition, growth responses and fatty acid content of the isolate under different temperature conditions were investigated to assess its physiological traits and aquaculture potential. Cells were 26.3–41.5 μm long (34.8 ± 3.6 μm) and 19.8–40.8 μm deep (28.9 ± 4.8 μm), and a nucleus located in the dorsal half of the cell and pyrenoid surrounded by a starch sheath were observed. Scanning electron microscope observations revealed that the cells displayed a plate formula of apical pore complex (APC), 4′, 6C, 4S, 5′′′, 5p and 1′′′′, and were characterized by a lack of precingular plates, scattered thecal pores, a single flagellar pore and a shallow anterior cingulum. One or two pores were present on the plate 3p, and one pore was consistently observed on plate 4p. Together with morphological characterizations, the phylogenetic analyses based on the SSU and LSU revealed that the Korean isolate can be identified as Pseudadenoides kofoidii that has not previously been described in Korean coastal area. The Korean isolate of P. kofoidii appeared to prefer moderate temperatures (15 and 20℃) rather than higher temperature (25℃), and could tolerate an abrupt temperature decrease from 20℃ to 10℃ and 15℃. No compositional changes were observed in the fatty acids of P. kofoidii exposed to abrupt temperature changes. Although this species exhibited temperature-dependent variation in PUFAs (DHA and EPA) content, P. kofoidii maintained remarkably high levels of polyunsaturated fatty acids (PUFAs) in its fatty acid composition (>42% of total fatty acid content), highlighting its potential as a promising new marine fatty acid resource for aquaculture applications.
 

TAXONOMY,ECOLOGY,AQUACULTURE APPLICATION