Lagons

Lagons are shallow coastal bodies of water separated from a larger sea by a barrier such as a sandbar, barrier island, or coral reef. Lagoons are found along many shores and also behind coral atolls. They can be open to the sea through inlets or tunnels, though the exchange is often limited.

Lagoons develop through sedimentation and sea-level changes. Coastal lagoons form when sediment builds a barrier that restricts direct seawater entry; in tropical regions, coral reefs commonly create barrier lagoons. Inland lagoons may form behind dunes, in floodplains, or in karst depressions.

Hydrology and ecology: Water is typically brackish; salinity varies with rainfall, evaporation, groundwater input, and the degree of connection to the sea. The water is often stratified; habitats include seagrass beds, mangroves, and salt marshes; the communities support numerous fish, crustaceans, birds, and invertebrates.

Human interactions and threats: Lagoons provide fisheries, tourism, and coastal protection; they filter runoff but are vulnerable to pollution, dredging, sedimentation, and development. Climate change and sea-level rise threaten their hydrology and habitats.

Conservation and management: Many lagoons are designated as protected areas and Ramsar sites; management aims to balance exploitation with habitat conservation; restoration efforts include reconnecting tidal flows, stabilizing barriers, and reducing nutrient inputs.