TY - JOUR
T1 - Differential Responses of Growth and Photochemical Performance of Marine Diatoms to Ocean Warming and High Light Irradiance
AU - Wu, Yaping
AU - Zhang, Mengjuan
AU - Li, Zhenzhen
AU - Xu, Juntian
AU - Beardall, John
PY - 2020/9
Y1 - 2020/9
N2 - Diatoms have relatively high biomass in mid- to high-latitude oceans, which is also the most sensitive region to climate change. Photoautotrophs are thus predicted to become exposed to both higher temperatures and increased solar 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 energetic expenditure required by the diatoms to repair damage could lead to their lower overall growth in future oceans.
AB - Diatoms have relatively high biomass in mid- to high-latitude oceans, which is also the most sensitive region to climate change. Photoautotrophs are thus predicted to become exposed to both higher temperatures and increased solar 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 energetic expenditure required by the diatoms to repair damage could lead to their lower overall growth in future oceans.
UR - http://www.scopus.com/inward/record.url?scp=85085006235&partnerID=8YFLogxK
U2 - 10.1111/php.13268
DO - 10.1111/php.13268
M3 - Article
C2 - 32222969
AN - SCOPUS:85085006235
SN - 0031-8655
SP - 1074
EP - 1082
JO - Photochemistry and Photobiology
JF - Photochemistry and Photobiology
ER -