Diel tuning of photosynthetic systems in ice algae at Saroma-ko Lagoon, Hokkaido, Japan

Shimpei Aikawa, Hiroshi Hattori, Yasushi Gomi, Kentaro Watanabe, Sakae Kudoh, Yasuhiro Kashino, Kazuhiko Satoh

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Ice algae are the major primary producers in seasonally ice-covered oceans during the cold season. Diurnal change in solar radiation is inevitable for ice algae, even beneath seasonal sea ice in lower-latitude regions. In this work, we focused on the photosynthetic response of ice algae under diurnally changing irradiance in Saroma-ko Lagoon, Japan. Photosynthetic properties were assessed by pulse-amplitude modulation (PAM) fluorometry. The species composition remained almost the same throughout the investigation. The maximum electron transport rate (rETRmax), which indicates the capacity of photosynthetic electron transport, increased from sunrise until around noon and decreased toward sunset, with no sign of the afternoon depression commonly observed in other photosynthetic organisms. The level of non-photochemical quenching, which indicates photoprotection activity by dissipating excess light energy via thermal processes, changed with diurnal variations in irradiance. The pigment composition appeared constant, except for xanthophyll cycle pigments, which changed irrespective of irradiance. These results indicate that ice algae tune their photosynthetic system harmonically to achieve efficient photosynthesis under diurnally changing irradiance, while avoiding damage to photosystems. This regulation system may be essential for productive photosynthesis in ice algae.

Original languageEnglish
Pages (from-to)57-72
Number of pages16
JournalPolar Science
Issue number1
Publication statusPublished - 2009 Jun
Externally publishedYes


  • Diurnal change
  • Ice algae
  • Non-photochemical quenching
  • Photosynthesis
  • Saroma-ko Lagoon

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Ecology
  • Earth and Planetary Sciences(all)


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