Effects of feeding and light intensity on the response of the coral Porites rus to ocean acidification@en

Recently, it has been suggested that there are conditions under which some coral species appear to be resistant to the effects of ocean acidification. To test if such resistance can be explained by environmental factors such as light and food availability, the present study investigated the effect of 3 feeding regimes crossed with 2 light levels on the response of the coral Porites rus to 2 levels of pCO2 at 28 °C. After 1, 2, and 3 weeks of incubation under experimental conditions, none of the factors-including pCO2-significantly affected area-normalized calcification and biomass-normalized calcification. Biomass also was unaffected during the first 2 weeks, but after 3 weeks, corals that were fed had more biomass per unit area than starved corals. These results suggest that P. rus is resistant to short-term exposure to high pCO2, regardless of food availability and light intensity. P. rus might therefore represent a model system for exploring the genetic basis of tolerance to OA.近年来已有研究表明，在特定条件下部分珊瑚物种可对海洋酸化（ocean acidification, OA）的影响产生抗性。为探究此类抗性是否可由光照、食物可获得性等环境因素解释，本研究设置3种投喂模式与2种光照水平的交叉实验，于28℃条件下探究该组合效应对两种二氧化碳分压（pCO2）水平下块状滨珊瑚（Porites rus）响应的影响。在实验条件下培养1、2、3周后，包括二氧化碳分压在内的所有实验因素，均未显著影响单位面积钙化率与单位生物量钙化率。前两周珊瑚生物量亦未受各因素影响，但培养至第3周时，投喂组珊瑚的单位面积生物量显著高于饥饿处理组。上述结果表明，块状滨珊瑚对短期高二氧化碳分压暴露具有抗性，且该抗性不受食物可获得性与光照强度的影响。因此，块状滨珊瑚可作为探究海洋酸化耐受遗传基础的模式系统。