Florida Keys National Marine Sanctuary

The Seagrasses and Mangroves of the Keys and surrounding region are highly productive and essential ecological habitats for numerous species that live in the Florida Keys National Marine Sanctuary. Turtle grass (Thalassia testudinum) is the dominant submerged macrophyte in both areal extent and biomass. Manatee grass (Syringodium filiforme) and shoal grass (Halodule wrightii) are found where conditions prevent dense turtle grass growth. Manatee grass is prevalent in deep channels on the outer fringes of Florida Bay, while shoal grass is common in shallow waters on banks or adjacent to mangrove islands.

Most islands are fringed by red mangroves, which form a narrow outer border of taller trees at the periphery and exhibit the characteristics of the fringe mangrove forest. A broader zone of black mangroves generally dominates inside the red mangrove fringe.

Numerous species of algae occur on the reefs of the Florida Keys including encrusting red algae of the genera Lithothamnium, Goniolithon, and Peyssonellia. Other plants present include Halimeda opuntia, Bryopsis pennata, Dictyota spp., Udotea conglutiata and Galazura obtusat.

The South Florida and Florida Keys region contains one of North America’s most diverse assemblages of terrestrial, estuarine, and marine fauna. The area has mangrove-fringed shorelines, mangrove islands, seagrass meadows, hardbottom habitats, thousands of patch reefs, and one of the world's largest coral reef tracts, which create one of the most complex ecosystems on Earth that houses thousands of animal species. Bisecting the region is the Florida Keys, which serve as a partial biogeographic barrier between the warm-temperate waters of the Gulf of Mexico and the tropical to subtropical waters of the Atlantic Ocean. This division has resulted in a marine ecosystem with fauna components that are found in both the warm-temperate and tropical Caribbean.