Coral calcification under daily oxygen saturation and pH dynamics reveals the important role of oxygen
Coral calcification under daily oxygen saturation and pH dynamics reveals the important role of oxygen
复制标题
日常氧饱和度和 pH 动态下的珊瑚钙化揭示了氧的重要作用
作者：
T. Wijgerde;Catarina I. F. Silva;V. Scherders;Judith D L van Bleijswijk;R. Osinga
摘要珊瑚礁对许多国家至关重要，目前全球正在衰退。虽然气候模型预测海水pH值（0.03个单位）和氧饱和度（0.05个百分点）会下降，但许多珊瑚礁目前的每日pH值和氧波动（pH值7.8-8.7和27- 241%O2饱和度）超过了这些。 我们研究了氧气和pH值波动对珊瑚钙化的影响，在实验室中使用的模式物种鹿角珊瑚millepora。海水pH值的增加使轻度钙化率大大提高（+178%），但仅在常氧条件下;高氧完全否定了这种积极作用。在缺氧条件下，暗钙化率明显受到抑制（51-75%），而pH值没有影响。我们的初步结果表明，在目前的氧气和pH值范围内，氧气对珊瑚生长有很大的控制作用，而pH值的作用是有限的。在这个气候迅速变化的时代，这对珊瑚礁的形成产生了影响，同时由于水温升高和沿海富营养化，海水氧饱和度下降。
ABSTRACT Coral reefs are essential to many nations, and are currently in global decline. Although climate models predict decreases in seawater pH (∼0.3 units) and oxygen saturation (∼5 percentage points), these are exceeded by the current daily pH and oxygen fluctuations on many reefs (pH 7.8–8.7 and 27–241% O2 saturation). We investigated the effect of oxygen and pH fluctuations on coral calcification in the laboratory using the model species Acropora millepora. Light calcification rates were greatly enhanced (+178%) by increased seawater pH, but only at normoxia; hyperoxia completely negated this positive effect. Dark calcification rates were significantly inhibited (51–75%) at hypoxia, whereas pH had no effect. Our preliminary results suggest that within the current oxygen and pH range, oxygen has substantial control over coral growth, whereas the role of pH is limited. This has implications for reef formation in this era of rapid climate change, which is accompanied by a decrease in seawater oxygen saturation owing to higher water temperatures and coastal eutrophication.