Vásquez-Elizondo Román Manuel, Enríquez Susana
Unidad Académica de Sistemas Arrecifales Puerto Morelos (Reef System Academic Unit), Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México (ICML-UNAM), Apartado postal 1152, Cancún, Q. Roo 77500, Mexico.
Sci Rep. 2016 Jan 7;6:19030. doi: 10.1038/srep19030.
In this study we analyzed the physiological responses of coralline algae to ocean acidification (OA) and global warming, by exposing algal thalli of three species with contrasting photobiology and growth-form to reduced pH and elevated temperature. The analysis aimed to discern between direct and combined effects, while elucidating the role of light and photosynthesis inhibition in this response. We demonstrate the high sensitivity of coralline algae to photodamage under elevated temperature and its severe consequences on thallus photosynthesis and calcification rates. Moderate levels of light-stress, however, were maintained under reduced pH, resulting in no impact on algal photosynthesis, although moderate adverse effects on calcification rates were still observed. Accordingly, our results support the conclusion that global warming is a stronger threat to algal performance than OA, in particular in highly illuminated habitats such as coral reefs. We provide in this study a quantitative physiological model for the estimation of the impact of thermal-stress on coralline carbonate production, useful to foresee the impact of global warming on coralline contribution to reef carbon budgets, reef cementation, coral recruitment and the maintenance of reef biodiversity. This model, however, cannot yet account for the moderate physiological impact of low pH on coralline calcification.
在本研究中，我们通过将三种具有不同光生物学特性和生长形态的藻体暴露于降低的pH值和升高的温度下，分析了珊瑚藻对海洋酸化（OA）和全球变暖的生理响应。该分析旨在区分直接效应和综合效应，同时阐明光照和光合作用抑制在这种响应中的作用。我们证明了珊瑚藻在温度升高时对光损伤高度敏感，以及这对藻体光合作用和钙化率的严重影响。然而，在pH值降低的情况下，维持了适度的光胁迫水平，尽管仍观察到对钙化率有适度的不利影响，但对藻类光合作用没有影响。因此，我们的结果支持以下结论：全球变暖对藻类性能的威胁比海洋酸化更大，特别是在珊瑚礁等高光照栖息地。我们在本研究中提供了一个定量生理模型，用于估计热胁迫对珊瑚碳酸盐产量的影响，有助于预测全球变暖对珊瑚礁碳预算、礁体胶结、珊瑚补充以及礁体生物多样性维持中珊瑚藻贡献的影响。然而，该模型尚未考虑低pH对珊瑚藻钙化的适度生理影响。
