As saturation levels fall, the energy required for calcification will increase, and calcification rates will decline. Eventually, saturation levels may drop so low that corals quit calcifying altogether, but long before that point, they will be in trouble. This is because out in the real world, reefs are constantly being eaten away at by fish and sea urchins and burrowing worms. They are also being battered by waves and storms, like the one that created One Tree. Thus, just to hold their own, reefs must always be growing.
