Differential responses of growth and photochemical performance of marine diatoms to ocean warming and high light irradiance

In this study we examined the consequences of such changes for the growth and photo‐physiology of two diatoms by mimicking the scenarios that correspond to present day and that predicted for the end of this century. Elevated light induced higher rates of damage to photosystem II (PSII) that significantly reduced photochemical yields of both diatoms. Treatments including UV radiation induced ~ 50% inhibition of PSII under present PAR levels. Generally, warming alleviated UVR inhibition, resulting in higher photochemical yields, and faster recovery during dim light exposure. Therefore, concurrent increase of irradiance and temperature mitigated UV inhibition of PSII by 8‐15%. The growth was stimulated by warming under PAR treatment, while less stimulation, or even decreased growth rates, were found under the PAR+UVR treatment. Results suggest that ocean warming could fully offset the inhibition of high light on PSII. However, under the latter higher UVR stress scenario, the energet ic expenditure required by the diatoms to repair damage could lead to their lower overall growth in future oceans.

Source: Photochemistry and Photobiology - March 28, 2020 Category: Science Authors: Yaping Wu, Mengjuan Zhang, Zhenzhen Li, Juntian Xu, John Beardall Tags: RESEARCH ARTICLE Source Type: research