Photoacclimation strategy of ice algal community in the seasonal sea ice

Abstract

Samples containing algal cells were collected from the bottom layers of sea-ice in Saroma-Ko Lagoon, Hokkaido, Japan in early spring 2010–2012. The physical and biogeochemical parameters of brine and sea ice, the structure of the ice algal community, and their photosynthetic characteristics were determined. Light responses of the relative electron transport rate (rETR) of the communities were estimated by quantum yield (ΔF/Fm′) of photosystem II at various light intensities with a pulse amplitude modulation (PAM) fluorometer. Although the compositions of the communities were different between the three years, their maximum quantum yields (Fv/Fm) were well correlated to in situ light attenuation. In contrast, their light acclimation index (Ek), the ratios of maximum rETR to the efficiency of the relative electron transport (α), varied year by year. This suggests that the ice algal communities have effective lightharvesting capabilities and their photoacclimation strategy might be related to the structure of the community.