To test the hypothesis that terrestrial runoff affects the functions of calcareous sediments in coral reefs and hampers the development of corals, we analysed calcareous sediments with different levels of bound phosphate, collected from reef areas of Okinawajima, Japan. We confirmed that phosphate bound to calcareous sediments was readily released into ambient seawater, resulting in much higher concentrations of phosphorous in seawater from heavily polluted areas (4.3–19.0 µM as compared with less than 0.096 µM in natural ambient seawater). Additionally, we examined the effect of phosphate released from calcareous sediments on the development of Acropora digitifera coral juveniles. We found that high phosphate concentrations in seawater clearly inhibit the skeletal formation of coral juveniles. Our results demonstrate that calcareous sediments in reef areas play a crucial role in mediating the impact of terrestrial runoff on corals by storing and releasing phosphate in seawater.

为了检验假说，地表径流会影响珊瑚礁中钙质沉积物的功能并阻碍珊瑚的发育，我们分析了从日本冲绳岛珊瑚礁地区收集的钙磷含量不同的钙质沉积物。我们证实，与钙质沉积物结合的磷酸盐很容易释放到周围的海水中，导致重度污染地区的海水中磷的浓度更高（4.3-19.0 µM，而自然环境海水中的磷含量低于0.096 µM）。此外，我们检查了钙质沉积物中释放的磷酸盐对棘指藻发育的影响。珊瑚少年。我们发现海水中的高磷酸盐浓度明显抑制了珊瑚少年的骨骼形成。我们的结果表明，礁石区的钙质沉积物通过在海水中储存和释放磷酸盐来介导陆地径流对珊瑚的影响中起着至关重要的作用。