High abundances of crustose coralline algae inside cryptic coral habitats linked to coral reef functioning.

Cryptic habitats on coral reefs consist of crevices, tunnels, and holes that are estimated to comprise 30%-75% of the total reef surface area. These large habitats are vastly understudied because they are often difficult to access. Crustose coralline algae (CCA) are thought to perform important ecological functions, including calcium accretion, both inside cryptic habitats and on the exposed (top) reef.