Longstreet Highroad Guide to the Florida Keys & Everglades
By Rick Ferren
John Pennekamp and the Key Largo Marine Sanctuary contain three unique types of coral reefs: outer bank reefs, inner bank reefs, and patch reefs. Outer bank reefs include popular Pennekamp diving sites such as Elbow, Molasses, French, and Carysfort reefs. They are characterized by a series of long limestone ridges that alternate with sandy channels. The ridges support live coral formations, called spur-and-groove, along their length. The spur-and-groove formations can be found in depths from 5 to 30 feet.
A flat sand and seagrass area can also be found on the back side of the reefs. These shallow areas contain many important invertebrates and young corals. A part of the outer reef bank known as the intermediate reef extends from 30 to 70 feet and is characterized by low-profile corals, large fish, and sponges.
Key Largo Dry Rocks, where the Christ of the Deep statue is located, is a prime example of an inner bank reef. Unique to Florida, these reefs have smaller spur-and-groove formations on the seaward side, but also the flat, shallow top and well-formed circumference of the larger patch reefs.
Found in the park's shallow waters, patch reefs are distinguished by a sandy perimeter, or "halo." Inhabited by many varieties of tropical fish, they are ideal for snorkeling and shallow scuba diving. The sides of these reefs are usually quite steep beginning near the surface and going as deep as 20 feet. Many flexible corals, such as sea fans and sea whips, grow on the patch reefs.