ABSTRACT: Coralline algae play foundational roles in coastal ecosystems and are globally significant components of benthic habitats down to the limits of the photic zone. Despite their vulnerability to ocean acidification (OA) and importance in low light environments, there is a limited understanding of how the interplay between irradiance and OA influences coralline reproduction and recruitment. To better understand this interaction, a 212 d experiment was run exposing coralline communities to 2 pH levels (present-day pH 8.03, OA pH 7.65) and a gradient of daily light dose (0.35, 0.17 and 0.1 mol m^-2 d^-1), based on in situ measurements. In the highest light dose treatment, lowered seawater pH projected for 2100 (pH_(T) 7.65) reduced recruitment by 56%. This OA-driven reduction in recruitment was amplified under reduced light, with recruitment near zero in the lowest light treatment. This study shows, for the first time, the increased vulnerability of coralline community recruitment to OA under low light. Coralline algae are known to be the deepest growing macroalgae and thus, in these low light zones, OA may have the potential to reduce coralline depth distribution.

中文翻译：

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低辐照度放大了海洋酸化对珊瑚藻群落补充的负面影响

摘要：珊瑚藻在沿海生态系统中发挥着基础性作用，并且是低至光区极限的底栖栖息地的全球重要组成部分。尽管它们容易受到海洋酸化 (OA) 的影响并且在弱光环境中很重要，但人们对辐照度和 OA 之间的相互作用如何影响珊瑚繁殖和补充的了解有限。为了更好地理解这种相互作用，进行了 212 天的实验，将珊瑚群落暴露于 2 个 pH 水平（当前 pH 8.03，OA pH 7.65）和日光剂量梯度（0.35、0.17 和 0.1 mol m ^-2 d ^-1 )，基于原位测量。在最高光剂量处理中，降低海水 pH 值预计为 2100 (pH _(T)7.65) 招聘减少了 56%。这种 OA 驱动的招募减少在减弱的光线下被放大，在最低光处理中招募接近零。这项研究首次表明，在弱光下珊瑚群落招募对 OA 的脆弱性增加。众所周知，珊瑚藻是生长最深的大型藻类，因此，在这些低光照区域，OA 可能有可能减少珊瑚深度分布。