To protect natural reefs, we can build new reefs, artificial ones. Artificial reefs mimic, or copy, natural ones, but they can be created for different purposes. Some artificial reefs prevent coastal erosion. They force waves to deposit their energy offshore rather than directly on the coastline. Other artificial reefs are meant to hold sediment on beaches. Still others simply provide a habitat for fish and other aquatic life.
To build an artificial reef, a large object is usually installed in an area where the sea bottom is flat and featureless. When ocean currents encounter a large enough object, a plankton-rich upswelling occurs. That becomes a good spot for small fish to feed. This, in turn, draws larger fish to the area.
The object may also make a good hiding place for hole- and crevice-dwellers like snapper, eels, and triggerfish. Over months and years, the object provides hard surfaces to which algae and invertebrates such as barnacles, corals, and oysters can attach. As time passes, the community of sea life connected to the object becomes more and more complex and diverse.
These statues have been underwater for several years. Corals and algae grow on them. Fish swim among them.
Artist Jason deCaires Taylo carefully crafts the face on one of the underwater statues.
Creating an artificial reef takes time, and it’s not as simple as tossing an old tire into the ocean and waiting for it to sprout life. MUSA president Roberto Abraham says that one of the greatest challenges they faced in creating the underwater museum sculptures was using the right cement.
If the cement isn’t strong enough, the statues crumble over time. If the surface is too acidic, corals and algae can’t take hold and grow. Once the MUSA staff and artists found the right mix, they were able to create the statues. Then, they hand-seeded many of the statues. They placed young staghorn coral polyps on the surface of the statues to give the growth a head start. The transformation is slow but miraculous. “When we place these sculptures underwater they start out like a blank canvas,” Abraham says. “But soon nature paints them and provides textures. They evolve every day.”
Corals decorate these MUSA statues.
Art isn’t the only architecture that can be used to make an artificial reef. Abandoned oil rigs can also double as reefs! Oil rigs are enormous structures built in deep water. Typically, they are built on the continental shelf, which is made up of clay, mud, and sand. There, they drill for oil.
When these rigs are no longer in use, the Rigs to Reefs program turns them into deep-sea artificial reefs. In the United States, many of the Gulf States participate in this program. To date, more than 500 rigs have been converted, mostly in Texas and Louisiana. The rigs can be cut off at the base and tipped over. Or, they can be cut in half and the pieces arranged side-by-side. The rig can even be cut into pieces and hauled to a different location.
This rig may one day become part of an artificial reef.
Surrounded by fish, these corals grow on an artificial reef.
Helping Out a Giant
A typical rig can provide a habitat for as many as 14,000 fish! Per square foot, the rigs can support more marine life than natural reefs do. Creatures come to these rigs because the steel is a good surface for corals and sponges. Red snapper, hogfish, and barracudas make the rigs their home.
These rigs are helping revive a species that was once severely threatened. Goliath groupers have been protected since 1990 but are still vulnerable. These fish can grow to more than 2.4 meters (8 feet) long and can weigh almost 363 kilograms (800 pounds). In recent years, they have been most abundant near deep, artificial reefs. Keith Mille with the Florida Fish and Wildlife Conservation Commission has observed them on some of his dives. To him, it’s first‑hand evidence that the artificial reefs are supporting key species.