Photosynthetic responses of Arctic sea-ice microalgae to short-term temperature acclimation

摘要

In April-May 1986, sea-ice microalgae (southcastern Hudson Bay, Canadian Arctic) were acclimated to temperatures ranging from-1.5° to 10°C for short periods (3 h), after which photosynthesis and carboxylating enzyme activities were measured. Pmaxbincreased after acclimation to 10°C while photosynthetic parameters α, β and Ikas well as activities of PePC and PePCk did not show any significant change after temperature acclimation. Contrary to Pmaxb, the activity of RuBPC was lower for algae acclimated to 3°-10°C, the observed response increasing with temperature. There was also a seasonal trend in the response of RuBPC, the ability to compensate for rapid temperature changes being higher in May. These results show that ice algae were photosynthetically adaptable in the range of temperatures tested. For RuBPC, adaptability developed seasonally when the environmental temperature started to fluctuate in May. Photosynthetic acclimatization to temperature may be of high ecological significance in extending the growth season of ice