Take a moment to imagine the sea architecture of a coral reef surrounded with schools of bright colored fish, which are visible through crystal clear water. Then a human comes on the scene; a diver swims to the side of the reef, exploring and enjoying his day in nature. He is stunned when he notices that the reef is built on the New York City subway car.
Artificial reefs are built to promote marine life expansion, control erosion, block ships from passage and even improve surfing, fishing and diving. Some are created in tropical areas where there is a “featureless bottom” sea floor, usually within a couple of hundred feet from shore.
Sinking oil rigs (Rigs-to-Reefs program), construction debris, shipwrecks or intentionally scuttled ships provide hard surfaces where algae, barnacles, oysters and corals attach. These structures eventually serve as the ecosystem, where marine-life thrives and fishermen and recreational divers enjoy their activities.
“Hard bottom” or “live-bottom” reef areas in the United States are located above the southern tip of Florida and off the southeastern coastal states from North Carolina to Florida. These areas have a hard surface (usually limestone rock) where sponges, corals and other invertebrates can attach to create natural reefs. Sadly these “live bottom” areas are very limited; only five to ten percent of South Carolina’s coast has a sea floor, where these reefs can naturally occur.
In “hard bottom” areas, artificial reefs are sometimes created to increase a more productive habitat. When suitable durable and environmentally safe materials (steel, concrete or New York City subway cars) are placed on the ocean floor while nature does the rest. Most artificial reefs will be active for one to five hundred years, or as long as the material they are built of survives.