Screening of Ice Activity of Polar Microalgae

Abstract

Diatoms and other microalgae in sea ice are major primary producers in polar marine ecosystem. Of these organisms, polar cryophilic microalgae are cold-adapted microorganisms which grow well in 2℃ to 3℃ but not over 10℃. We have more than 100 microalgal strains from Dasan Station, Arctic and King Sejong Station, Antarctic in KOPRI culture collection for polar microorganisms (KCCPM). These organisms are cultivating at 3℃ and 24h light conditions. Among them, six Antarctic and one Arctic microalgal strains were screened by observing ice pitting and formation of ice crystals. Antarctic strains were KOPRI AnM0002, KOPRI AnM0010, KOPRI AnM0014, KOPRI AnM0041, KOPRI AnM0046, and KOPRI AnF0048. Arctic strains were KOPRI ArM0016.To identify activities of ice binding, we have used our own designed instrument for observing ice pitting and nanoliter-osmometer for ice crystals. All seven microalgal strains were shown to have formations of hexagonal ice crystals. Especially, KOPRI AnM0010, KOPRI AnM0014, KOPRI AnM0041, and KOPRI ArM0016 were forming clear hexagonal crystals. These results indicate that these cryophilic microalgae have strong ice binding activities. KCCPM has many cryophilic microalgae not been completely isolated. In other words, there are lots of microalgal strains that ice binding activities should be screened. We will observe and identify ice binding and antifreeze activities of KCCPM strains continuously.