Articles | Volume 14, issue 22
Research article
14 Nov 2017
Research article |  | 14 Nov 2017

Differential photosynthetic responses of marine planktonic and benthic diatoms to ultraviolet radiation under various temperature regimes

Yaping Wu, Furong Yue, Juntian Xu, and John Beardall

Abstract. We studied the photophysiological responses to ultraviolet radiation (UVR) of two diatoms, isolated from different environmental niches. Both species showed the highest sensitivity to UV radiation under relatively low temperature, while they were less inhibited under moderately increased temperature. Under the highest temperature applied in this study, the benthic diatom Nitzschia sp. showed minimal sensitivity to UV radiation, while inhibition of the planktonic species, Skeletonema sp., increased further compared with that at the growth temperature. These photochemical responses were linked to values for the repair and damage processes within the cell; higher damage rates and lower repair rates were observed for Skeletonema sp. under suboptimal temperature, while for Nitzschia sp., repair rates increased and damage rates were stable within the applied temperature range. Our results suggested that the response of the microalgae to UV radiation correlated with their niche environments, the periodic exposure to extreme temperatures promoting the resistance of the benthic species to the combination of high temperature and UV radiation.

Short summary
Diatoms were less inhibited by UV radiation under moderately increased temperature. Benthic diatoms were more resistant to UV radiation than planktonic species under extremely high temperature as found in the intertidal zone. These differential responses were linked to repair and damage processes of photosystem II.
Final-revised paper