Hae Jin Jeonga,b,*, Kyung Ha Leea,*, Yeong Du Yooc, Nam Seon Kangd, Jae Yoon Songa,Tae Hoon Kime, Kyeong Ah Seongc, Jae Seong Kime, Eric Potvina
aSchool of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Republic of Korea
bAdvanced Institutes of Convergence Technology, Suwon, Gyeonggi-do, 16229, Republic of Korea
cDepartment of Marine Biotechnology, Kunsan National University, Kunsan, 54150, Republic of Korea
dMarine Biodiversity Institute of Korea, Seochun-gun, Chungchungnam-do, 33662, Republic of Korea
eWater and Eco-Bio Corporation, Kunsan National University, Kunsan, 54150, Republic of Korea
*Corresponding authors
Abstract
Among mixotrophic dinoflagellates, the maximum mixotrophic growth rate of the red-tide dinoflagellate Paragymnodinium shiwhaense is relatively high, whereas mortality due to predation is low. To investigate the effects of major environmental parameters on P. shiwhaense, growth and ingestion rates of one strain of P. shiwhaense on the algal prey species Amphidinium carterae (also a dinoflagellate) were determined under various light intensities (0-500 μE m-2s-1), water temperatures (5-30 °C), and salinities (5-40). Cells of P. shiwhaense did not grow well in darkness but grew well at light intensities ≥ 10 μE m-2s-1. There were no significant differences in either growth or ingestion rates of P. shiwhaense fed A. carterae at light intensities between 10 and 500 μE m-2s-1. Furthermore, P. shiwhaense did not grow at 5 °C or ≥ 28 °C. Its growth rates between 7 and 26 °C were significantly affected by temperature, and the optimal temperature for maximal growth was 25 °C. With increasing salinity from 5 to 20, the growth rate of P. shiwhaense fed A. carterae increased and became saturated at salinities between 20 and 40, while the ingestion rate at salinities between 10 and 40 did not significantly change. Thus, overall, the growth and ingestion rates of P. shiwhaense fed A. carterae were affected by temperature and salinity, but not by light intensity other than darkness. These findings provide a beginning basis for understanding the ecology of this potentially harmful algal species in marine coastal ecosystems.
Keywords : Feeding, Ingestion, Irradiance, Physiology, Protist, Red tide