Bioerosion
The physical wearing away and breakdown of coral reef structures by organisms—fish, sea urchins, and other creatures—that scrape, bore, or grind away at the calcium carbonate skeleton.
The process by which marine organisms mechanically erode and fragment coral reef structures. Fish, sea urchins, mollusks, and other creatures bore into, scrape, or grind away at the calcium carbonate skeleton through feeding, burrowing, or movement, gradually breaking down the reef's physical framework independent of chemical dissolution.
What this means in real life
A parrotfish grazes on algae growing on a coral head, scraping away the underlying limestone with its beak-like mouth—over time, this feeding behavior, multiplied across thousands of fish, physically grinds down the reef structure into sand.
What it isn’t
It is not the same as coral bleaching or disease, which kill the living coral animal itself. Bioerosion is the mechanical breakdown of the dead skeleton that remains after corals die, not the death of the coral tissue.
Commonly misused online
Often conflated with 'coral death' or 'reef destruction' as if they are the same process. In reality, bioerosion is a natural, ongoing process that accelerates when reef-building corals decline, but it is distinct from the causes of that decline.