Which world coastlines have many barrier island lagoons?

Barrier island lagoons are widely distributed, accounting for approximately 13 percent of the world's total coastline. These features typically form on low or moderate-energy coasts, particularly along the eastern edges of continents where wave swells are less intense, and in high-latitude regions where offshore ice provides protection.1

Key locations where barrier island lagoons are common include:

• Europe: The southern Baltic coast, the southeast North Sea, the Black Sea, the Caspian Sea, and the Mediterranean Sea.1
• North America: The southeastern United States and the Gulf of Mexico.1
• South America: Southern Brazil.1
• Asia and Oceania: Northeastern Russia, Japan, Australia, and New Zealand.1
• Other regions: The east coast of Madagascar and isolated sections of the African and Indian coastlines.1

These lagoons thrive in areas with low to moderate tidal ranges and require an abundant supply of sediment, typically sand, to construct the protective barrier islands.12