Submerged Solutions: How Artificial Reefs Rebuild Habitats

By Kelley Northam

Tropical ocean waters are often adorned with the hallmark pinks, oranges, and purples found in coral reefs. These beautiful living structures are thousands of years old and provide food, shelter, and breeding grounds for fish, barnacles, sea turtles, and millions of other organisms.

But, due to climate change, pollution, and extreme weather, coral reefs are dying, displacing marine life from their natural habitats. Between 2009 and 2014, the Global Coral Reef Monitoring Network found that 14 percent of coral had vanished from our oceans, and this decline is only expected to continue.

Ocean conservation and sustainability efforts can help combat this trend, but scientists around the globe are acting now to rebuild reef habitats using artificial reefs.

Sunken Structures

Artificial reefs are human-made structures intentionally submerged in bodies of water to foster aquatic life. These structures encourage coral growth and help provide the nutrition and space marine life needs to thrive. They also help protect coastlines from erosion and support sustainable fishing practices.

Sunken ships have incidentally become artificial reefs, but now retired metal ships are purposefully sunk to create artificial reefs. The ships are unloaded and cleaned, towed out to sea, and safely sunk in a pre-determined area.

Various concrete structures can also serve as artificial reefs. Some have even become underwater art galleries, such as the Molinere Underwater Sculpture Park by artist Jason deCaires Taylor, attracting coral and scuba divers alike.

Revolutionary Reefs

In addition to providing habitats for marine life, natural reefs protect coastlines from storm damage. But because climate change is causing more extreme weather, these reefs are being damaged and destroyed, leaving coastlines vulnerable.

To mitigate this, a team of Massachusetts Institute of Technology (MIT) engineers are designing an artificial reef to help fortify coastlines. Described in an MIT News article, unlike sunken ships, this reef’s design is far more compact—it’s a cylindrical structure with four slats that resemble ship rudders. When a wave crashes against the structure, water flows between the slats, breaking the wave’s energy and causing the water flow to go toward the sides instead of toward the shore. In their testing, they found that the design could reduce as much wave energy as traditional artificial reefs but use 10 times less material.

In addition to mitigating storm damage, this artificial reef will be made of a more sustainable, fish-friendly cement. The MIT team intends to mold the cement into microstructures that resemble egg cartons to create crevices where fish can live.

By repurposing old structures and engineering new ones, conservationists and scientists are leveraging artificial reefs to protect the human and aquatic residents of coastal communities around the globe.