Photosynthetic responses of the marine diatom Thalassiosira pseudonana to CO₂-induced seawater acidification

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• 作者：Qi Shi ; Wenqun Xiahou ; Hongyan Wu
• 关键词：Ocean acidification ; Diatom ; Thalassiosira pseudonana ; Photosynthesis
• 刊名：Hydrobiologia
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：788
• 期：1
• 页码：361-369
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Freshwater & Marine Ecology; Ecology; Zoology;
• 出版者：Springer International Publishing
• ISSN：1573-5117
• 卷排序：788

文摘

Ocean acidification due to atmospheric CO₂ rise is expected to influence marine phytoplankton. Diatoms are responsible for about 40% of the total primary production in the ocean. In order to investigate the physiological response of marine diatom Thalassiosira pseudonana to ocean acidification, we grew the cells under ambient CO₂ level (380 µatm) versus the elevated CO₂ level (800 µatm) at a light level of 180 µmol m−2 s−1 for 30 generations. Our results showed that the elevated CO₂ concentration caused a decrease of the effective photochemical efficiency of PSII \(\left( {{{F_{{\text{v}}}^{\prime } } \mathord{\left/ {\vphantom {{F_{{\text{v}}}^{\prime } } {F_{{\text{m}}}^{\prime } }}} \right. \kern-\nulldelimiterspace} {F_{{\text{m}}}^{\prime } }}} \right)\) and increase of the dark respiration in T. pseudonana. The intracellular carbonic anhydrase activity was suppressed and the photosynthetic affinity for CO₂ was lowered in the high CO₂-grown cells, reflecting a downregulation of the CO₂ concentrating mechanism (CCM). PSI activity was enhanced to support an increase in ATP synthesis by cyclic electron transfer as required for transport of inorganic carbon and regulation of intracellular pH. The energetic benefit from the downregulation of CCM to growth as reported in other diatom species was not observed here in T. pseudonana.