High-temperature tolerance of a brown alga Eisenia bicyclis collected from different localities

Abstract

Kelp forests are important in coastal ecosystems as primary producers and
habitat for marine organisms. However, recent global warming has been inducing reductions of kelp forests in various parts of the world. This study investigated high-temperature tolerance of a representative kelp forest constituent Eisenia bicyclis collected from southern edge (Itoshima, Fukuoka Prefecture) and central (Tateyama, Chiba Prefecture) population. Adult sporophytes collected from the fields and juvenile sporophytes derived from gametophytes were used for the comparison. The sporophytes were cultivated under different temperature conditions: 20, 22, 24, 26, 28 and 30 ℃. Then, the maximum quantum yield (F_v /F_m) was measured using Imaging-PAM. The adult and juvenile sporophytes from Fukuoka maintained significantly higher F_v /F_m at 30 ℃ than those from Takeyama. This indicates that E. bicyclis from southern population (Fukuoka) has high-temperature tolerance.