Artificial reefs often add a touch of intrigue to a dive. There is something eerie about coming upon a structure common on dry land when you dip underwater. But while artificial reefs and scuttled wrecks often provide habitats for marine life, they are not always beneficial to the environment.
What is an artificial reef?
Generally, an artificial reef is anything manmade that you might see underwater. These could include structures specially designed to encourage coral growth, purposefully scuttled vessels and, of course, ships and planes that sank due to either weather conditions or as victims of war. In time, most of these artificial reefs become a home for new life, as polyps (baby coral) need hard substrate to attach to and grow on.
Artificial reefs long predate modern history as well; Japanese fishermen in the Middle Ages made them from bamboo. More recently objects made from various materials, such as concrete, have been employed to create underwater experiences for divers as well as in an attempt to generate healthy underwater ecosystems.
How do artificial reefs benefit the marine environment?
As mentioned, artificial reefs provide a substrate where coral polyps can attach to regenerate and grow. Over time, these areas can become flourishing ecosystems, attracting a variety of marine life. The placement of artificial reefs can also help reduce coastal erosion. Furthermore, artificial reefs can increase the amount of oxygen being produced underwater. This, in turn, reduces oxygen deficiency in the deeper areas of the ocean.
Reefs that see many divers each year are often exposed to larger amounts of damage, aside from that caused by pollution, rising CO2 and water temperature levels. Novice and irresponsible divers can cause damage to coral reefs that might take years to regenerate. Artificial reefs provide divers with additional areas to explore, taking pressure off natural reef systems in the area.
What are some of the drawbacks of artificial reefs?
Artificial reefs, while taking some pressure off of natural reefs, can also attract more visitors to the area in general. Thus, while divers and snorkelers might visit an area because of an artificial reef, they will likely pair that with a number of visits to natural reefs in the area, which could lead to more damage on the reefs. Also, if they aren’t carefully monitored, artificial reefs can become habitat and spawning grounds for invasive species, such as orange-cup coral.
The creation of artificial reefs involves intensive planning, long-term monitoring and evaluation so as not to cause damage to the surrounding marine ecosystems or change the equilibrium of species native to the area.
Wrecks like old planes and ships can carry pollutants like asbestos, PCBs, floating debris and fuels. It is crucially important that these objects are thoroughly cleaned before they are scuttled. It is also important to consider the material used for artificial reefs. In the 1970s, about 2 million old tires were dumped off the Florida coast in an ill-advised attempt to create an artificial reef. Very little marine life has attached to the tires, which have subsequently become unmoored and destroyed natural substrata, as well as decomposing and floating in pieces in the ocean.
While artificial reefs can take pressure off natural reefs and encourage marine life growth and rehabilitation, it is important to follow the correct procedures when planning and installing these structures.