Why massive blooms of the fish-killing harmful dinoflagellate Cochlodinium polykrikoides did not occur along the Tongyeong coast (South Korea) in 2016

Title
Why massive blooms of the fish-killing harmful dinoflagellate Cochlodinium polykrikoides did not occur along the Tongyeong coast (South Korea) in 2016
Author(s)
백승호
KIOST Author(s)
Baek, Seung Ho(백승호)
Publication Year
2017-11-23
Abstract
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 September. The environmental differences between 2016 and previous years (2012-2015) were investigated. In August, the water temperatures (c.a.,30°C) and the salinity (c.a., 30) were outside the optimum ranges for C. polykrikoides growth in the study area. Moreover, the averages of these factors were significantly different from previous years (p<0.001). In 2016, the amount of Changjiang River discharge, which can affect coastal environments via ocean currents, was relatively larger than in the past four years, reducing the salinity in August. Throughout this study, the reason why the Cochlodinium bloom did not occur or spread to the Tongyeong coasts in 2016 was investigated. To summarize, (i) a larger than average amount of Changjiang River discharge was observed in July, 2016, and the Changjiang diluted water approached the Tongyeong coasts 1 month after the discharge, which resulted in abnormally low salinity and higher water temperatures in the offshore waters in August, (ii) the surface water currents driven by the westward wind prohibited the eastward expansion of the C. polykrikoides blooms along the Goheung-Oenarodo coast, (iii) a typhoon that resulted survey from June to September. The environmental differences between 2016 and previous years (2012-2015) were investigated. In August, the water temperatures (c.a.,30°C) and the salinity (c.a., 30) were outside the optimum ranges for C. polykrikoides growth in the study area. Moreover, the averages of these factors were significantly different from previous years (p<0.001). In 2016, the amount of Changjiang River discharge, which can affect coastal environments via ocean currents, was relatively larger than in the past four years, reducing the salinity in August. Throughout this study, the reason why the Cochlodinium bloom did not occur or spread to the Tongyeong coasts in 2016 was investigated. To summarize, (i) a larger than average amount of Changjiang River discharge was observed in July, 2016, and the Changjiang diluted water approached the Tongyeong coasts 1 month after the discharge, which resulted in abnormally low salinity and higher water temperatures in the offshore waters in August, (ii) the surface water currents driven by the westward wind prohibited the eastward expansion of the C. polykrikoides blooms along the Goheung-Oenarodo coast, (iii) a typhoon that resulte
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/23560
Bibliographic Citation
한국해양바이오학회, pp.74, 2017
Publisher
한국해양바이오학회
Type
Conference
Language
English
Publisher
한국해양바이오학회
Related Researcher
Research Interests

Marine Ecology,Marine Environment,HABs,해양생태,해양환경,적조

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