caa a22 4500 445893184 CHVBK 20180317145623.0 cr unu---uuuuu 170323e20111001xx s 000 0 eng 10.1007/s10750-011-0807-0 doi (NATIONALLICENCE)springer-10.1007/s10750-011-0807-0 Solar ultraviolet radiation and CO2-induced ocean acidification interacts to influence the photosynthetic performance of the red tide alga Phaeocystis globosa (Prymnesiophyceae) [Elektronische Daten] [Shanwen Chen, Kunshan Gao] Future CO2-induced ocean acidification may interact with solar UV radiation to affect physiological performance of microalgae. Therefore, CO2/pH perturbation experiments were carried out under solar radiation with or without UV radiation (295-400nm) to evaluate the combined effects of seawater acidification (pH 7.7 at 101.3Pa CO2) and UV on Phaeocystis globosa that forms harmful algal blooms. Under high levels of solar radiation, the acidification reduced the growth rate and photochemical efficiency either under PAR alone or with the presence of UVR radiation. Under reduced levels of solar radiation (cloudy days), however, the CO2-enrichment and UVA acted synergistically to stimulate the photochemical yield and enhanced the growth rate. That is, the effects of CO2-induced acidification were reversed from the negative (sunny days) to positive (cloudy days). CO2 concentrating mechanism f P. globosa was not affected by the elevated pCO2 in view of unchanged photosynthetic affinity for CO2 and stable activity of both intracellular and extracellular carbonic anhydrase. The increased acidity induced higher UVB-related photoinhibition of growth and non-photochemical quenching, and increased the dark respiration and the contents of Chl a, Chl c, and carotenoids, causing the cells to increase their energy demand against the combined stress. Overall, the findings imply that net or balanced effects of ocean acidification on phytoplankton would depend on the depth or mixing that alters the exposures of the cells in water columns to solar radiation. Springer Science+Business Media B.V., 2011 CO2 nationallicence Growth nationallicence Ocean acidification nationallicence Phaeocystis globosa nationallicence Photochemical yield nationallicence UV nationallicence PAR : Photosynthetically active radiation nationallicence PSII : Photosystem II nationallicence UVA/B/R : Ultraviolet-A/-B/radiation nationallicence P : PAR alone nationallicence PA : PAR+UVA nationallicence PAB : PAR+UVA +UVB nationallicence Chen Shanwen Marine Biology Institute, Shantou University, 515063, Shantou, China aut Gao Kunshan State Key Laboratory of Marine Environmental Science, Xiamen University, 361005, Xiamen, China aut Hydrobiologia Springer Netherlands 675/1(2011-10-01), 105-117 0018-8158 675:1<105 2011 675 10750 https://doi.org/10.1007/s10750-011-0807-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10750-011-0807-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Chen Shanwen Marine Biology Institute, Shantou University, 515063, Shantou, China aut NATIONALLICENCE 700 1- Gao Kunshan State Key Laboratory of Marine Environmental Science, Xiamen University, 361005, Xiamen, China aut NATIONALLICENCE 773 0- Hydrobiologia Springer Netherlands 675/1(2011-10-01), 105-117 0018-8158 675:1<105 2011 675 10750 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer