Which type of coral reef is characterized by a circular or continuous barrier reef surrounding a lagoon without any central island?

💡 Solution & Explanation

An atoll is a ring-shaped coral reef system that encircles a central lagoon completely or partially without any visible central landmass or island. Fringing reefs develop directly along coastlines, whereas barrier reefs are separated from the land by a deeper lagoon. Charles Darwin proposed the subsidence theory to explain the gradual evolution of fringing reefs into barrier reefs and atolls.