Inhibition of massive blooms of Cochlodinium polykrikoides due to abnormal high temperature from Changjiang River discharge in Korea

Abstract

For the past 20 years, blooms of Cochlodinium polykrikoides have been consistently present along the Tongyeong coast, Korea, but they abruptly disappeared in 2016. Despite extensive studies on this dinoflagellate, the cause of this abrupt decline remains largely unknown. To understand these phenomena, physico-chemical and biological data were collected along the Tongyeong coast through a biweekly field survey from June to Septembe. In the Goheung-Oenarodo area, which is thewestern part of the southern Korean coastal waters (KCW), C. polykrikoides blooms were observed, but they did not expand to the entire southern KCW, unlike in previous years. At that time,the strong winds from the Malakas typhoon may have terminated the bloom. In addition, westward winds may have inhibited the spread of the bloom eastward along the Tongyeong coast. The combination of these environmental factors may have contributed to the decline of massive C. polykrikoides blooms.ecline remains largely unknown. To understand these phenomena, physico-chemical and biological data were collected along the Tongyeong coast through a biweekly field survey from June to Septembe. In the Goheung-Oenarodo area, which is thewestern part of the southern Korean coastal waters (KCW), C. polykrikoides blooms were observed, but they did not expand to the entire southern KCW, unlike in previous years. At that time,the strong winds from the Malakas typhoon may have terminated the bloom. In addition, westward winds may have inhibited the spread of the bloom eastward along the Tongyeong coast. The combination of these environmental factors may have contributed to the decline of massive C. polykrikoides blooms.