第12回 生命科学科セミナー

日時 ： 令和7年　6月26日（金）

　　　　　13時00分～14時00分

会場 ： 日本大学文理学部3号館　3309教室

講師 ： Sung Mi Cho
  韓国極地研究所 Senior Researcher
  University of Science and Technology (韓国) 教授

Antarctic Snow Algae Across Scales: From Environmental Distribution to Photosynthetic Supercomplexes

Sung MI Cho

Division of Life Sciences, Korea Polar Research Institute (KOPRI), Incheon 21990, South Korea

Contact: smcho@kopri.re.kr

Snow algae are major primary producers in seasonal snow ecosystems and play important ecological roles in cryospheric carbon cycling and surface albedo reduction. Despite their ecological significance, the physiological adaptation mechanisms underlying their survival and diversification in extreme snow environments remain insufficiently understood. In particular, the relationship between microenvironmental heterogeneity and photosynthetic adaptation in Antarctic snow algae has received relatively limited attention.

In this seminar, I will introduce our recent studies on Antarctic snow algae collected from Barton Peninsula, King George Island, maritime Antarctica, with a focus on their diversity, ecological distribution, and temperature-dependent physiological responses. Our recent work identified a novel snow-associated green algal lineage, Chloromonas bartonica, which was isolated from transitional snow–terrestrial habitats. Integrative analyses combining morphology, phylogeny, environmental distribution patterns, and ecophysiological experiments suggested that microenvironmental heterogeneity may contribute to lineage diversification in Antarctic snow algae.

In addition, I will present ongoing comparative studies on psychrophilic and cold-tolerant snow algal strains, including analyses of photosynthetic performance under temperature stress using chlorophyll fluorescence approaches. These results indicate that Antarctic snow algae exhibit diverse physiological strategies for coping with fluctuating thermal conditions.

Finally, I will discuss future research directions focusing on the structural and functional regulation of photosynthetic machinery in snow algae, particularly temperature-dependent dynamics of thylakoid membrane protein supercomplexes. By integrating ecological observations, physiological experiments, and photosynthetic membrane analyses, this research aims to provide a mechanistic understanding of cold adaptation in cryophilic microalgae and contribute to broader insights into photosynthetic acclimation under rapidly changing polar environments.