The implications of ocean acidification are acute for calcifying organisms, notably tropical reef corals, for which accretion generally is depressed and dissolution enhanced at reduced seawater pH. We describe year-long experiments in which back reef and fore reef (17-m depth) communities from Moorea, French Polynesia, were incubated outdoors under pCO₂ regimes reflecting endpoints of representative concentration pathways (RCPs) expected by the end the century. Incubations were completed in three to four flumes (5.0 × 0.3 m, 500 L) in which seawater was refreshed and circulated at 0.1 m s⁻¹, and the response of the communities was evaluated monthly by measurements of net community calcification (NCC) and net community productivity (NCP). For both communities, NCC (but not NCP) was affected by treatments and time, with NCC declining with increasing pCO₂, and for the fore reef, becoming negative (i.e., dissolution was occurring) at the highest pCO₂ (1067–1433 μatm, RCP8.5). There was scant evidence of community adjustment to reduce the negative effects of ocean acidification, and inhibition of NCC intensified in the back reef as the abundance of massive Porites spp. declined. These results highlight the risks of dissolution under ocean acidification for coral reefs and suggest these effects will be most acute in fore reef habitats. Without signs of amelioration of the negative effects of ocean acidification during year-long experiments, it is reasonable to expect that the future of coral reefs in acidic seas can be predicted from their current known susceptibility to ocean acidification.

中文翻译：

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长年暴露于高 pCO2 对后礁和前礁群落代谢的影响

海洋酸化对钙化生物的影响非常严重，尤其是热带珊瑚礁，在海水 pH 值降低的情况下，钙化生物的增生通常会受到抑制，而溶解会增强。我们描述了为期一年的实验，其中法属波利尼西亚莫雷阿岛的后礁和前礁（17 米深）群落在 pCO ₂制度下在户外孵化，反映了预计到本世纪末的代表性浓度路径 (RCP) 的终点。孵化在三到四个水槽（5.0 × 0.3 m，500 L）中完成，其中海水以 0.1 m s ^-1的速度更新和循环，每月通过净群落钙化（NCC）和净群落钙化的测量来评估群落的反应。社区生产力（NCP）。对于这两个群落，NCC（但不是 NCP）受到处理和时间的影响，NCC 随着 pCO _{2 的}增加而下降，而对于前礁，在最高 pCO ₂ (1067–1433 μ)时变为负值（即发生溶解）。 atm、RCP8.5）。没有足够的证据表明群落进行了调整以减少海洋酸化的负面影响，并且随着大量滨珊瑚的大量存在，后礁对 NCC 的抑制作用增强。拒绝了。这些结果强调了海洋酸化对珊瑚礁的溶解风险，并表明这些影响在前礁栖息地中最为严重。在长达一年的实验中，如果海洋酸化的负面影响没有改善的迹象，我们可以合理地预期，可以根据目前已知的对海洋酸化的敏感性来预测酸性海洋中珊瑚礁的未来。