Estuaries are places of transition from land to sea, supporting unique communities of plants and animals especially adapted to life at the margin of the ocean. Estuaries are among the most productive and complex ecosystems. Estuaries and their associated wetlands provide essential habitat for wildlife. Many organisms rely on estuaries for food, places to breed, and serve as stopovers during migration. Humans also rely on estuaries for food, recreation, jobs, and coastal protection.