Sunk On Purpose

Did you know that the coastlines of the United States have become a dumping ground for old ships, subway cars, and tanks, among other things? Sounds like a major source of ocean pollution, right? Well, think again. All of these items have been placed onto the bottom of the ocean on purpose as a way to build up marine habitat.

The Adolphus Busch, a 210-foot cargo ship, was deliberately sunk in the Florida Keys to serve as an artificial reef. (Photo credit: Michael Patrick O’Neill/Alamy)

What Is an Artificial Reef?

Though exact definitions vary, according to the International Maritime Organization, an artificial reef refers to any submerged structure deliberately constructed or placed on the seabed to emulate some functions of a natural reef such as protecting, regenerating, concentrating, and/or enhancing populations of living marine resources. Some marine scientists also consider structures that are designed for other purposes–such as bridges, piers, and docks–to have the potential to be artificial reefs as well.

Though many states now regulate what can and cannot be used as an artificial reef, in previous years, there was a lot less regulation. This anything goes attitude led to a number of unfortunate projects, including the dumping of over 700,000 tires off the coast of Fort Lauderdale. Lauded as a way to both improve marine habitat and get rid of waste that would otherwise end up in a landfill, this ill begotten project continues to wreak havoc with the Florida coast today. Though the tires were strapped together, these straps were often no match for tropical storms, and many have since come apart. Tires can now roll freely along the ocean floor, destroying natural coral reefs. In addition, a number of tires end up as garbage on the beach after washing ashore. Marine scientists hope to learn from these past mistakes use these lessons as cautionary tales in the development of current artificial reef projects.

In recent years, a number of human-made items have been plunged to the bottom of the ocean. What exactly is down there? Artificial reefs are constructed of concrete slabs, small boats, aircraft carriers, subway cars, and tanks. Some artificial reefs are not made up of these re-purposed materials and are instead constructed especially for use as an artificial reef. Several companies make specialized structures specifically for use as an artificial reef. These structures vary in shape in size, and include mound, pyramid, and cube shapes.

Advantages of Artificial Reefs

Artificial reefs are often lauded as a means to not only increase habitat for fish and other marine species, but also as a way to boost the local economy. Unusual artificial reefs, such as sunken subway cars or ships, are quite popular destinations for recreational divers. Artificial reefs are also touted as excellent locations for sport fishing. For example, a study conducted in 2001 by researchers at the University of Florida IFAS Extension estimated that non-residents and tourists spent $1.7 billion annually on fishing and diving activities associated with artificial reefs in southeast Florida.

This structure was built specifically for use as an artificial reef. (Photo credit: Poelzer Wolfgang / Alamy)

Disadvantages of Artificial Reefs

However, not everyone is convinced that artificial reefs are a good thing. Some marine scientists are concerned that items pushed into the sea, even though thoroughly cleaned of grease and other potential contaminants beforehand, may still contribute to ocean pollution. The tire incident of the 1970s is a clear example that not everything is suitable to become an artificial reef. Conservationists also worry that instead of protecting marine species, such as ocean-dwelling fish, artificial reef just serve to draw populations away from their natural habitats, concentrating them around the artificial reef. This makes them easy pickings for sport fishers, and in no way abates the worry of the overfishing of the oceans. Another concern is the lack of federal regulations to oversee artificial reef programs around the United States. Currently, artificial reefs are managed on a state-by-state basis, and each state has a different set of criteria that they follow.

What Do You Think?

Clearly, there are many advantages and disadvantages to the use of artificial reefs. Where do you stand on the topic of artificial reefs? Do you think they are a good idea or a bad idea? Do the benefits of artificial reefs to a marine ecosystem and to the local economy outweigh their costs? Where do you stand?