Unveiling the Growth Characterizations of Dinoflagellates Causing Red Tides

- Published in the January issue of Science Advances

The Ministry of Oceans and Fisheries (MOF; Minister MOON, Seong-Hyeok) announced that a research team supported by the Ministry of Ocean and Fisheries (MOF) revealed growth characterizations of marine red-tide dinoflagellates and uni-celluar plankton, and published the results in the issue of January 9th of Sciences Advances, a highly prestigious journal.

‘Dinoflagellates’ have two flagella and make a whirl when they swim. In marine ecosystems, they play important roles as prey for larvae of fish and shellfish. Dinoflagellates and are major producers of O2 as they absorb CO2 and Nitrogen, but at times, their overgrowth can cause red tides.

A research team leaded by Professor Hae Jin Jeong at Seoul National University, Korea revealed growth characterizations of marine dinoflagellates while conducting a project called “Development of infra-technologies of increasing useful dinoflagellates and controlling parasitic ciliates using marine dinoflagellates” which the MOF supported since 2016. The research team found that 15 of 3,500 formally described dinoflagellate species caused red tides in the waters of more than 10 countries throughout 1990-2019. These 15 species have been found in the Korean waters.

To reveal growth characterizations of these 15 dinoflagellates causing red tide globally, the research team analyzed the ecological and genetic characterizations of 7 newly found species of dinoflagellates from Korean coastal waters and then compared their characterizations.

The research team found that these 15 dinoflagellates causing global red tides were mixotrophic and could survive under unfavorable photosynthesis conditions by feeding on prey, although their growth rates were relatively slow. In particular, the mixotrophic dinoflagellate species having diverse species of prey cause global red tides, whereas those having one or a few species of prey caused one or no red tides.

The results of this study will serve as an important knowledge when predicting the population dynamics of red tide dinoflagellates and thus establishing an accurate prediction system for red tide outbreaks. This system is expected to be useful in minimizing the losses in aquaculture industry caused by large-scale mortalities of finfish and shellfish.

Dinoflagellates often take more than 20% of the annual carbon retention of marine organisms in marine ecosystems. Thus, identifying which dinoflagellate species dominate is useful for better understanding carbon cycling and eventually achieving carbon neutrality*, a big global issue.

*Balancing carbon dioxide emissions with carbon offsets

The project entitled “Development of infra-technologies of increasing useful dinoflagellates and controlling parasitic ciliates using marine dinoflagellates” will end in this year. However, establishing new dinoflagellate species after isolating cells in Korean waters and developing methods of increasing their populations will continue.

In Kyung Kim, the Director of Marine and Fisheries Bioresources Division, said “The results of this study can be used to develop models that help predict the outbreak of red tides in advance.” She added “The MOF plans to provide continued support for R&D projects with potential to produce useful outcomes in marine biotechnology and also contribute to marine environmental issues.”