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Artificial reefs and their impact on existing ecosystems
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Coral reef ecosystems play an important role in the development of the marine environment; providing food, shelter, and breeding grounds for a large array of marine organisms. There are, however, limitations to coral reef growth. Temperate coral reefs (those found in areas outside of the tropics) occur only in areas where nature has provided suitable hard substrate to which corals, sponges, and several sedentary crustaceans can attach themselves. These hard bottom areas are not very common; and it is for this reason, among many others, that artificial reefs are being constructed along areas such as the eastern coast of the United States. These artificial reefs are creating populations in what would otherwise be barren landscape or “featureless flat bottom”(Block). However, it is hard to say whether or not artificial reefs are performing a positive function or whether they are simply moving existing populations to areas where they would yield a larger commercial gain.

It has long been known by many fishermen that the best places to catch fish were around the sites of shipwrecks and other debris that litters the ocean floor. Because of this many residents of coastal areas realized that if they placed their own underwater structures, new fishing grounds would be established. So in 1953, the state of Alabama gave permission for the dumping of “things like car bodies, old tires, refrigerators, clothes washers, and even shopping carts” to create sea-floor structures that would bring in game fish (Bailey 42). By the 1970’s, all of the coastal states of the United States were dumping large refuse into the ocean to create so-called artificial reefs. These materials of opportunity, as they are now called by scientists, began to cause several problems. Being unmarked and uncontrolled fishing boats would drag fishing nets over the reefs and tear the fishing nets. At the same time, because none of the objects were fitted so they stayed stationary underwater, pieces of junk were being carried onto the beaches by waves. The beached debris upset the locals as well as tourists because it dirtied up the coastline. The majority of the population involved in this dumping of materials of opportunity did not realize that saltwater will corrode almost any structure within a few years, so half of the objects dumped never turned into ecosystems because they were so short lived (42). metal objects that are corroded are usually of two substances, copper and steel. Both of these metals are easily corrupted by seawater and both have negative effects in the water column. Copper is toxic to invertebrates including corals and shrimp; steel will result in an increase of free floating iron, which in turn stimulates algal growth as opposed to coralline growth. The government realized the problem, and, by 1997, many states, including Alabama, banned the use of materials of opportunity with the intention of establishing artificial reefs.

To this day, however, materials of opportunity are still being used to create artificial reefs along the eastern coast of the United States. The materials most commonly used are tires, subway cars, and decommissioned Navy ships. All of these objects contain materials or chemicals that are hazardous to the environment as well as to marine organisms, such as: asbestos, PCB (polychlorinated Biphenyls), paint, fossil fuels, battery acid, mercury, and lead. There are few regulations on the removal of substances from possible reef material, but the Environmental Protection Agency (EPA) has drawn up a draft for possible guidelines that should be followed for the removal of hazardous substances from decommissioned ships prior to them being sunk. What the government and private companies are stating as promoting marine ecosystems may just be “the cheapest way to dispose of oversized objects”(Boyce 71).

In an attempt to rid themselves of some redbird subway cars, “the city’s transit system is retiring some 1,400 of the 1960’s era crimson-colored subway cars”(Block). Here is the catch, according to the New York City Transit, it would cost an estimated $13 million to properly dispose of these cars. So the city has found a loophole to retiring the 1,400 cars without spending a single penny by offering to give the subway cars away free of charge to any state that will use them to create artificial reefs. The State of Delaware has agreed to take 400 cars, which will then, “be cleaned and stripped and then sunk off the Delaware coast, 20 at a time, to create an artificial reef for fish and marine life”(Block).

Jeff Tinsman, the reef program coordinator for Delaware’s Department of Natural Resources and Environmental control, believes that the subway cars will supply the hard bottom substrate that is needed for blue mussel communities to thrive. When he was questioned on the subject of asbestos he stated, “we feel[the department], and our federal brothers support us, that asbestos is basically a problem when it is floating in the air”(Block). Research has shown for the most part that asbestos has no adverse effects underwater, even when inside the guts of fish and shellfish; this can be noted by observing the “many wrecks and ships that were sunk during World War II that had a huge, huge quantities of friable asbestos on board”(Block). Tinsman said that the federal government backed his program up ,yet the EPA stated in its report

preparation should eliminate the possibility of pieces of asbestos breaking free from the vessel during the sinking operation or asbestos materials losing surface integrity after the vessel has been placed as an artificial reef. Loose pieces can lead to rafting and may be capable of washing ashore. These asbestos pieces could dry up, break apart, and be reintroduced into the atmosphere.

So even though the asbestos does not present a threat to the marine environment it does present a threat to the humans living along the coast near these artificial reefs if the asbestos is not removed from the subway cars.

To further show the lack of government regulation for the adequate construction of artificial reefs, NPR’s Melissa Block asked Jeff Tinsman how they were going to place the subway cars underwater, he simply replied that they would just push them off the side of a barge with a bulldozer. This shows just how unregulated artificial reefs can be. With nothing to hold the subway cars in place, no one can tell what will happen, whether or not the cars will be dragged by the tides, which could cause damage to the surrounding ecosystem. This incident mirrors that of the 1970’s when thousands of tires where dumped offshore to create artificial reefs, only later to realize that the “tires were light, easily damaged by strong undercurrents, and were ineffective as a fish shelter or spawning ground”(Zakaria). The worst effect was that the tires were “reacting chemically with the saltwater,” which led to contamination of the marine environment (Zakaria).

Under misguided pretenses of environmental improvement, the United States government has been dumping known hazardous substances into the marine habitat. The most common objects are decommissioned ships, which provide a large hard bottom area for reef formation. Originally, most of the ships were just placed in strategic locations and sunk, after having some items removed from the hull. This simple procedure resulted in several accidents such as, “a liberty ship sunk in 1976, leaked oil”(Boyce 70). The Environmental Protection Agency has guidelines, as a result of these accidents and recent studies, for the stripping and removal of hazardous substances such as oil and fuel, which have a variety of environmental impacts depending on the properties of the oil, but range from slicks to poisoning of marine organisms; asbestos, which has no known impact on the marine environment; polychlorinated biphenyls--man made organic compounds-- are known to bio-accumulate in the fatty tissues of organisms, which in turn can result in reproductive problems for many organisms; paint, which causes both acute and chronic toxicity; other miscellaneous objects that may have a negative effect in the marine environment such as battery acid (United States EPA). The USS Oriskany was the first decommissioned ship to undergo the EPA guidelines for decontamination for reefing; it was sunk in august 2004 (Boyce 70).

The government’s motivation for the sinking of decommissioned ships seems to have more to do with saving the government money than it does with improving the marine environment. It costs on average “around $20,000 a year for the Navy to maintain a decommissioned ship, though the clean up is expensive it still costs less than to have ships scrapped” this offshore sinking could save the Navy up to 1.5 billion dollars (Boyce 71). There are other economic advantages to artificial reefs, many of which are not in the least ecologically minded. The commercial fishing industry benefits from artificial reefs because they provides areas where fish are easily accessible. No scientific method has been created that can tell whether a new reef actually stimulates fish reproduction or whether it lures fish to areas where hooks await them (Boyce 71). The sports diving industry also benefits from artificial reefs, because they provide areas where divers can see a large concentration of fish in an area that would normally be devoid of any. There are perhaps a few ecological gains for the construction of artificial reefs.

Despite the lack of no scientific method to measure how beneficial an artificial reef ecosystem is to existing ecosystems, the increase in fish yields has led to the conclusion that artificial reefs have really resulted in an increase of fish reproduction by providing new breeding ground (Zakaria). Also when artificial reefs are constructed near overexploited natural reefs, the stress put on the populations of the ecosystem are relieved, allowing the natural reef to recover. Artificial reefs provide alternative diving spots, which also relieves the stress applied to existing reef systems by reducing the amount of damage done to the reef structure. Artificial reef research has greatly increased our knowledge about designing reef, so that now more artificial reefs are being designed for specific reasons, and it has led to the construction of specific materials just for the construction of reefs as well as the use of already existing structures. These structures are mainly oilrigs, which tend to accumulate a large biomass during their lifetime (Oil Rigs as reefs). Companies such as Reef BallsÔ have begun to construct hollow porous spheres of concrete that are ecologically sound and have an average lifetime of 500 years as opposed to the 100-year lifetimes of ships (Harris 1). Reef BallsÔ are being used primarily for repair of damaged reefs, but they are also being used as wave breakers.

Oilrigs have served as important breeding grounds for such fish as grouper and red snapper, both of which are slow to reproduce and are over harvested (Vitter). According to current government policies, oilrigs must be removed within one year of being out of operation. Due to this, ecosystems that have been forming around the structures during the years of operation are then ripped out of the sea causing a sudden collapse in the surrounding biomass which in turn causes a collapse in the ecosystem and a decline in fish populations. Over the years, scientists have realized the benefits of these rigs and have pushed for a bill to create an act that allows for all decommissioned rigs to be given a possible alternative of being artificial reefs. Chairman of Energy and Mineral Resources, David Vitter, has pushed for the passing of HR 2654, or the Rigs to Reef Act, which “will give the secretary of the interior authority to create a program to allow using decommissioned platforms for culturing marine organisms”. If the bill is passed the predicted 2,500 rigs that will be abandoned will be allowed to continue existing as artificial reefs (Oil).

What actually goes on underneath the water’s surface of an oil rig? Coral polyps and sedentary crustaceans are carried by the tides during their larval stage to these structures, where they bind to the surface of the legs. As coral population increase they draw in fish, crustaceans and other marine organisms. As more organisms are drawn to the area the more complex the interactions between them, resulting in the creation of an ecosystem. These ecosystems tend to foster as thriving communities of many rare and endangered species of marine invertebrates and fish. So if the rigs are allowed to stay then the ecosystems will continue to thrive and act as areas of scientific research to study the rare species of corals and to search for possible medicinal sources among these organisms (Vitter). These thriving artificial reefs can then be further aided with the addition of Reef BallsÔ to add additional surface space.

Reef BallsÔ have become the new future for artificial reef construction. They have been used as wave breakers, guide markers for snorkel and divers, increase the amount of hard bottom habitat which in turn relieves stress on existing reefs, and acting as obstacles for ships and nets (Harris 1). These spherical concrete structures have almost limitless number of functions. The construction of these balls involves the use of inert materials such as concrete, but allow for the customization of materials to meet specific needs such as the texture of the sphere, the addition of carbonate, and of other minerals and nutrients that are beneficial to reefs. Corals may be directly transplanted on to Reef BallsÔ to further mitigate coral growth and inhabitation by marine organisms. The spheres, being hollow had many holes leading to the inside where additional objects are added to add nooks and crannies that stimulate inhabitation of specific species such as the spiny lobster.

Artificial reefs serve both economical and ecological gains. Though the original motivation for artificial reef construction may have been negative; over the past years, due to the increase in scientific studies of artificial reefs, the population has become more aware of what materials are actually beneficial. This in turn has led to the decontamination of materials of opportunity, reducing their chances of polluting the marine environment, as well as the creation of reef material that is entirely ecologically minded and inert, therefore eliminating any possible pollution problems. As long as research continues to lead to a better use of artificial reefs, they will present a benefit to exploited and over stressed systems without harming existing populations and existing landscape.


Last edited by Megil Tel'Zeke at 16-Feb-2005 17:20

apparently no one likes long articles

i like it, very well written, good job Megil

Daka<<<<

Yup, people are too lazy to read it.

I did though! And it was very good. Lots of information, and very well written. Good job.

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They shade the glow of it with their mossy-misty costumes,
They wear masks of silk, porcelain, brass, and silver,
So as not to mislead with their own, ordinary faces.

nice article

a few questions come to mind tho
those reef balls r concrete which will b placed on sand
what depth r they being placed
sure there great but as tides n water n wind currents go will they b sunk into the sand?
n how long does it actually take for corals to begin to reproduce?
surely it cant b a fast process did u come across that information during ur reseach?

the reef balls are being placed on and around reef systems. i don't think the sand moves so drastically around reefs otherwise the reef structure would also be eventually covered with sand, which of course doesn't happen. i believe the reef adds as a buffer from the tides, preventing so much beach erosion.

as for coral growth it depends on the species. some i think will attach pretty readily id say a few months but other that are much slow growers probly don't start growing on the reef balls for some time possibly years.

for more information just find the reef ball website they have a a page of links that includes all sorts of documents regarding reef ball research.

Last edited by Megil Tel'Zeke at 17-Feb-2005 20:09

Im sure its a good artical(didn't bother reading it, no offence)