How does a fringing reef develop into a barrier reef?

According to the theory proposed by Charles Darwin, a fringing reef develops into a barrier reef through the process of land subsidence. As the landmass—typically a volcanic island—sinks, the reef continues to grow upward and outward to maintain its position near the water's surface. This upward growth creates a lagoon between the reef and the receding shoreline, effectively transforming the fringing reef into a barrier reef.12

While Darwin’s original concept remains foundational, modern science also attributes this development to the rise in sea level that followed the melting of ice sheets after the Pleistocene Epoch. In this context, the submergence of the landscape allows the reef to grow vertically, creating the characteristic separation between the reef and the mainland. Additionally, plate-tectonic theory explains that as the ocean floor moves away from oceanic ridges, it naturally subsides, facilitating the transition of reefs through these various developmental stages.1