Mesodinium rubrum infusoria has dyed the water of the Avacha Bay
The water of the Avacha Bay in Petropavlovsk-Kamchatsky turned purple and crimson again, as in September 2024, Kamchatka.Today reports with reference to the Kamchatka branch of the Pacific Institute of Geography of the Far Eastern Branch of the Russian Academy of Sciences.
The so-called red tide is caused by the spring flowering of the marine ciliate Mesodinium rubrum (Myrionecta rubra). On April 12, 2025, a local change in the color of the water was observed in the northeastern part of the Avacha Bay.
Employees of the Laboratory of Hydrobiology of the Kamchatka branch of the Institute examined water samples taken from the Avacha Bay. The research results showed that the discoloration of the water was caused by the non-toxic Mesodinium rubrum (Myrionecta rubra) infusoria, whose abundance in the surface layer of the water was 452 thousand cells/liter.
“The Myrionecta rubra species does not produce toxins, that is, it is non-toxic, but its mass reproduction is unsafe. In the traced food chain, Myrionecta rubra is the food of larger dinoflagellates and other planktonic organisms. In Avacha Bay, planktonologist Galina Konovalova recorded 12 toxic and potentially toxic species and forms of dinoflagellates. And although the Myrionecta rubra species occupies an intermediate place in the trophic chain, its massive development can be followed by the flowering of other microorganisms, including toxic dinoflagellates and diatoms feeding on myrionecta,” the scientists note.
As the temperature increases, the number of Myrionecta rubra will increase.
Photo by S.G. Korostelev