Artificial Reefs: Ocean Junk or Help for an Endangered Ecosystem?

Candice Gaukel Andrews by Candice Gaukel Andrews | February 8th, 2013 | 8 Comments
topic: Eco Travel, Green Living

Sea turtle

Coral reefs around the world are in trouble. According to the World Wildlife Fund, about one-quarter of coral reefs are considered damaged beyond repair, with another two-thirds under serious threat. Some suffer from heavy fishing pressures, while others are succumbing to pollution or careless tourism. Climate change, with its attendant rising sea temperatures, is exacerbating the problem, speeding coral deaths.

More than half a billion people live near corals, relying on them for food, shelter from storm surges and the income that tourism brings. With natural reefs diminishing, artificial reefs are increasingly gaining favor. These structures usually take the form of sunken ships, decrepit oil platforms or other human trash.

But is depositing more human refuse in the oceans in order to create artificial reefs healthy for the environment — and for us?

Turning trash to treasure

Kayak above reef

In some places, “reef tourism” is responsible for creating thousands of jobs. ©Tim Boyes

Coral reefs are a big part of the ocean food chain. Occupying less than one quarter of one percent of the marine environment, they are home to more than 25 percent of all known marine fish species. Coral reefs can yield an average of 15 tons of fish and other seafood per 0.38 square miles each year.

While a coral may look like a single entity, it’s actually a partnership between two microscopic organisms: a polyp, which is a tiny assemblage of mouths and tentacles; and a single-celled organism, usually an alga or dinoflagellate, which lives within that assemblage. The polyp builds a tiny calcium-carbonate structure that shelters the alga, and through photosynthesis, the alga provides food to the polyp. Millions of these little partnerships accumulate to form enormous, iconic reefs.

But warming waters can cause corals to expel their algal partners. The corals then turn bone white and die — a phenomenon called “bleaching.”

Unfortunately, according to the National Oceanic and Atmospheric Administration (NOAA), global sea surface temperatures have risen by about 1.5 degrees Fahrenheit over the last century. To put that in perspective, from 1876 to 1979 only three bleaching events were recorded. From 1980 to 1993, there were 60.

This decline of coral reefs has ecological and economic consequences. If the reefs vanished, experts say, hunger, poverty and political instability could ensue. Commonly consumed species of fish, such as grouper and snapper, could disappear altogether, while oysters, clams and other creatures — vital to many people’s diets — would also suffer. Commercial fisheries would not be able to meet the demand for seafood.

In Florida alone, more than 500 species of fish live and depend on coral reefs. In a state that is no stranger to storms, healthy reefs buffer up to 90 percent of the force of incoming waves, thus providing shoreline protection to people and property. Just in the Florida Keys, more than 33,000 jobs are dependent on ocean recreation and tourism, which accounts for 58 percent of the local economy and an average of $2.3 billion a year.

That’s why Florida has deployed derelict autos and old refrigerators in the Gulf of Mexico. Hard surfaces — whether natural coral or man-made — appeal to tiny creatures such as plankton, which in turn attract species up the food chain. Steel structures, especially, are soon covered by calcareous algae, which provide an adequate surface for coral larvae to grow quickly. The state of New York has sunk retired subway cars in the Atlantic in hopes of creating artificial reefs, and researchers in the Red Sea have found that several shipwrecks have become thriving coral communities.

These artificial reefs attract divers, easing human pressure on natural reefs. Artificial reefs can even enhance the development of rare coral species that are not often found in natural reefs. With time, say some scientists, there is no appreciable difference between a natural and artificial reef habitat.

Reef watchers needed

Disposing of our trash in the world’s waters isn’t without risk, however. There is a possibility that the metal structures can contribute to toxins in the ocean, which can affect and accumulate in any of the species that colonize the reefs. Anglers may be catching and consuming fish that have absorbed contaminants such as carcinogenic polychlorinated biphenyls (PCBs), as well as oil, asbestos and other pollutants leaching from sunken vessels.

Galapagos beach at sunset

Are artificial reefs helping to rebuild an endangered ecosystem, or polluting the ocean environment? ©Roberto Plaza

Too, dropping large objects into the sea to serve as artificial reefs can damage preexisting habitats or displace wildlife from their homes. And some artificial reefs have an unreliable safety record. According to Newsweek, an artificial reef composed of disused tires ended up coming apart, distributing two million tires throughout the sea and causing damage to natural reefs, boats and the shore. In addition, the safety of diving on decommissioned vehicles and vessels is questionable.

Another issue with artificial reefs involves who should monitor and maintain them once they are dropped into the water. Some artificial reefs require maintenance, repair or removal over time, which can be costly. They also need monitoring to track their effectiveness and impact on the environment.

Jane Lubchenco, a marine biologist who heads NOAA, was quoted as saying, “Reefs are precious sources of food, medicine and livelihoods for hundreds of thousands around the world. They are also special places of renewal and recreation for thousands more. Their exotic beauty and diverse bounty are global treasures.”

Reefs are certainly treasures that we can’t afford to lose, but they may also be ones we take a risk in making.

Do you think that creating artificial reefs with trash is a good way to help rebuild one of the world’s most endangered ecosystems, or a dangerous use of our garbage?

Happy trails,


Feature photo: Reefs appeal to tiny creatures such as plankton, which in turn attract species up the food chain. ©Jeff Foote


  1. We’re looking at the hotel and resort experience differently from both the environmental side and the regional tourism side with the addition of artificial reefs for tourism/snorkeling and dive training – unlike any that have been seen before.

    Reef Worlds Video

    Reef Worlds is developing complete underwater worlds for tourism and the environment. It’s an exciting and visually stunning new tourism paradigm. The ability to take waterfronts that have no tourism value, areas with sand bed bottoms, or regional areas where no tourism is present and create instant tourism by just integrating objects that take well known design cues (Mayan, Aztec, South Asia) to create engaging worlds underwater.

    Artificial Reefs have come of age. Gone are the days of costly ship drops, reef balls, and objects that have little to no tourism value, or value to a much smaller tourism base. With carefully designed and placed regional underwater worlds at depths of 20-40 feet, hotels and resorts can attract the widest audiences and governments can now set up regional tourism offerings in places where the natural environment is degraded.

    Example Cancun

    Fact is if you took a survey of all the PADI, NAUI and SSI divers in the world today and asked them how many dives they had actually done, including the training, the average number is six.

    There’s huge waiting market of divers and snorkelers out there who cannot, or should not dive past 40 feet, so the concept of a resort based artificial reef program placed in shallow waters not only addresses an untapped market segment but also reinvigorates waterfronts that currently have no interest to paying hotel guests. It’s time we got off the beach and back into the oceans.

    Additionally, 100% neutral artificial reef objects like the ones we are currently building become a haven for wildlife. These sites are quickly inhabited by a wide range of colorful fish and soft corals. These sites also aggregate mass tourism allowing natural reefs offshore to remain pristine.

    What we do is the future of artificial reefs.

    Mike Wallce | February 9th, 2013 | Comment Permalink
  2. Not if it means ignoring the original problem of rising water temperatures, pollution and run-off from over-used shorelines. Just another delaying tactic, denial of the causes, and a saleable solution for disposal of otherwise cumbersome unused items.

    Cindy Reid | February 15th, 2013 | Comment Permalink
  3. It’s a question of goal- fish productivity, hydrology/coastal protection, recreation/tourism, etc. A pile of ceramic roofing tiles might be a great thing for tiny lobsters & oysters, but snorkelers won’t like it much.

    Unfortunately many projects don’t properly establish their goal before going forward, so they end up doing something (often a costly something) that isn’t the best or correct solution, and sometimes provides an ecological negative.

    And yes, greenwashing a dump also counts as a “goal,” though it shouldn’t be supported.

    Andrew Ross | February 15th, 2013 | Comment Permalink
  4. Dumping more trash in the water to fix a problem that is partly caused by us dumping trash and pollutants, in the air and water, in the first place, doesn’t seem quite right to me.

    John H. Gaukel | February 17th, 2013 | Comment Permalink
  5. I think we should work on the big problem, global warming, rather than try to patch all the resulting problems with debatable “solutions” like putting our garbage in the ocean as artificial reefs. We humans should practice more responsible recycling in the form of responsible reuse. All kinds of toxic materials are going to come out of these old cars, refrigerators, any other type of old machinery thrown into the ocean and cause more pollution problems. I hope they at least had the sense to remove oil, lead, acids, gas, refrigerant and other obvious toxins from the machines before they dumped them!

    Tamara | February 17th, 2013 | Comment Permalink
  6. The experience of artificial reefs is still not complete. I think using garbage for building artificial reefs may lead to miss use of garbage without checking its content which might be toxic or unfavorable for reef or fish.

    Taher Issa | February 19th, 2013 | Comment Permalink
  7. Without a doubt the core issues of acidification, and water temps not to mention trophic collapse are all pressing issues, we are not ignoring them.

    Mike Wallce | February 22nd, 2013 | Comment Permalink
  8. [...] learning about some pros and cons of artificial reefs in this article. For further reading, check out the concept of green burials, where memorial reefs are set up to [...]

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