Nature World: Here's something you may not have known: tropical coral reefs are constantly building up and breaking down. In healthy ecosystems, the building will outpace the breakdown, keeping reefs growing and sturdy even as their erosion feeds predators (like worms and the unusual parrotfish).
However, in recent years, researchers have begun to worry that in the wake of elevated levels of ocean acidity our reefs are eroding faster than they can grow.
Extensive records have shown that one of the most iconic...