Original paper

Effect of temperature and light on growth of planktic green algae isolated from Lake Hovsgol, Mongolia

Tsujimura, Shigeo; Kumagai, Michio; Urabe, Jotaro; Sekino, Tatsuki; Hayami, Yuichi; Maruo, Masahiro


Four species of planktic green algae, Oocystella mongolica, Monoraphidium contortum, Pseudodidymocystis planctonica and Closterium parvulum were isolated from the ancient ultraoligotrophic Lake Hövsgöl, Mongolia. While O. mongolica is considered to be an endemic species of the lake, the others are cosmopolitan species. Lake Hövsgöl freezes between November and May, and the maximum water temperature in the pelagic area is ca. 14 °C in summer. In order to clarify the growth characteristics on temperature and light of the strains, culture experiments were conducted. Although these algae live in cold habitats, the optimum temperatures for growth of the strains were 20-25 °C under high light conditions. All strains could grow at 5 °C, which was the lowest temperature examined, and showed their best growth rate at 10 °C under the lowest light conditions (10 μmol photons m−2.s−1). The results of culture experiments were discussed with regard to their natural habitats.


endemic speciesgreen algaegrowth ratelake hovsgol (khubsugul)lightphytoplanktontemperature