What is an atoll?

An atoll is defined as a circular coral reef that encloses a lagoon. This geological feature typically forms around the rim of a volcanic island that has subsided over time. As the island erodes and sinks, corals continue to grow upwards, creating a ring-shaped structure with a central lagoon. This distinct formation is indicative of tropical marine environments and is important for biodiversity, providing habitat for various marine species. The structure of an atoll not only highlights the dynamic processes involved in coral reef development but also emphasizes the interconnection between geological and biological systems in marine ecosystems.