Jiang Lei, Guo Ya-Juan, Zhang Fang, Zhang Yu-Yang, McCook Laurence John, Yuan Xiang-Cheng, Lei Xin-Ming, Zhou Guo-Wei, Guo Ming-Lan, Cai Lin, Lian Jian-Sheng, Qian Pei-Yuan, Huang Hui
Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
Front Physiol. 2019 Jan 11;9:1952. doi: 10.3389/fphys.2018.01952. eCollection 2018.
Diurnal CO fluctuations have the potential to modulate the biological impact of ocean acidification (OA) on reef calcifiers, yet little is known about the physiological and biochemical responses of scleractinian corals to fluctuating carbonate chemistry under OA. Here, we exposed newly settled for 7 days to ambient CO, steady and elevated CO (stable OA) and diurnally fluctuating CO under future OA scenario (fluctuating OA). We measured the photo-physiology, growth (lateral growth, budding and calcification), oxidative stress and activities of carbonic anhydrase (CA), Ca-ATPase and Mg-ATPase. Results showed that while OA enhanced the photochemical performance of symbionts, it also increased catalase activity and lipid peroxidation. Furthermore, both OA treatments altered the activities of host and symbiont CA, suggesting functional changes in the uptake of dissolved inorganic carbon (DIC) for photosynthesis and calcification. Most importantly, only the fluctuating OA treatment resulted in a slight drop in calcification with concurrent up-regulation of Ca-ATPase and Mg-ATPase, implying increased energy expenditure on calcification. Consequently, asexual budding rates decreased by 50% under fluctuating OA. These results suggest that diel CO oscillations could modify the physiological responses and potentially alter the energy budget of coral recruits under future OA, and that fluctuating OA is more energetically expensive for the maintenance of coral recruits than stable OA.
昼夜CO波动有可能调节海洋酸化（OA）对珊瑚礁钙化生物的生物学影响，但对于造礁石珊瑚在OA条件下对波动的碳酸盐化学的生理和生化反应知之甚少。在此，我们将新附着的[具体对象]暴露于环境CO、稳定和升高的CO（稳定OA）以及未来OA情景下昼夜波动的CO（波动OA）中7天。我们测量了光生理学、生长（横向生长、出芽和钙化）、氧化应激以及碳酸酐酶（CA）、Ca - ATP酶和Mg - ATP酶的活性。结果表明，虽然OA增强了共生体的光化学性能，但也增加了过氧化氢酶活性和脂质过氧化。此外，两种OA处理都改变了宿主和共生体CA的活性，表明在光合作用和钙化过程中溶解无机碳（DIC）摄取的功能发生了变化。最重要的是，只有波动OA处理导致钙化略有下降，同时Ca - ATP酶和Mg - ATP酶上调，这意味着钙化过程中的能量消耗增加。因此，在波动OA条件下无性出芽率下降了50%。这些结果表明，昼夜CO振荡可能会改变未来OA条件下珊瑚幼体的生理反应并可能改变其能量收支，并且波动OA对维持珊瑚幼体来说比稳定OA在能量上消耗更大。
