KIOST-Central University Joint Research Team Discovers Phenomenon of Red Tide Increasing Marine Ecosystem Biodiversity

Published 17 Oct.2024 08:48(KST)

Increase in Zooplankton Biodiversity During Red Tide Occurrence

The Korea Institute of Ocean Science and Technology (KIOST), in collaboration with Chung-Ang University, discovered through joint research that red tide occurrences increase the biodiversity of zooplankton through complex interactions within the marine ecosystem, and published the research results in an international academic journal.

Korea Institute of Ocean Science and Technology.

Red tide, which mainly occurs in summer, is caused by the rapid proliferation of a type of phytoplankton distributed in the sea called ‘Cochlodinium (Margalefidinium polykrikoides)’. ‘Cochlodinium’ is known to attach to fish gills, reducing their oxygen exchange ability and causing fish mortality, thereby disrupting aquaculture fish and marine ecosystems.

Dr. Lee Yun-ho’s research team at KIOST, together with Professor Yoon Sung-il of Chung-Ang University, has been investigating the impact of red tide occurrences on the marine ecosystem in the Tongyeong area of the southern coast over the past seven years (2013?2019) through genetic analysis.

Comparing years with red tide occurrences (2013?2015) and years without (2016?2019), it was revealed that the biodiversity of zooplankton increased by more than 25% in the years when red tide occurred.

In years with red tide, the proportion of copepods (Copepoda), the dominant species constituting the marine ecosystem, decreased, while the proportion of larvae of various organisms such as branchiopods (Branchiopoda), echinoderms (Echinodermata), malacostracans (Malacostraca), and annelids (Annelida) increased, resulting in an overall increase in biodiversity. Larvae refer to young individuals floating in seawater.

The research team considered that the cause of this increase in biodiversity is the structural change in the marine ecosystem, where some organisms such as benthic invertebrates adapted to red tide perceive red tide occurrences as a signal for spawning and utilize it as favorable environmental conditions for survival and reproduction. They noted that organisms that have reproduced in environments with repeated red tides may gradually develop resistance to red tide and evolve to utilize red tide occurrences instead.

Lee Hee-seung, Director of KIOST, said, “This study shows that the impact of red tide occurrences on the marine ecosystem is much more complex than previously known,” and added, “We plan to conduct more in-depth research on the impact of red tide on marine resources in the future.”

Schematic diagram of the impact of red tide occurrence on the marine ecosystem.