5. The Reef-Olution: The Future of Human-Made Reefs

The Future of Coastal Protection Methods
In the past, artificial reefs have been made with old car frames, tyres, train carriages, and concrete rubble, but due to issues, like leaching toxins and physical instability, their use has declined. In 1970s Florida, USA, there were approximately two million tyres used to create an artificial reef - called the Osborne Reef (pictured below). This was created to attract fish and to repurpose old tyres to free up space in landfill sites. The reef was extremely unsuccessful as hurricanes and storms would move the tyres causing them to cover and damage existing corals. The leaching of toxic chemicals from the tyres killed and further hindered growth of coral, overall reducing the biodiversity in the area and creating a worse environment. While improving the environment is a good thing, and at most times necessary, it can be exploited. This can lead to greenwashing, in this instance, a practice in which companies dispose of waste materials under the misleading guise of creating ecological benefits.


Modern, sustainable reefs are often built from materials like concrete, steel, and natural stone, as these can be shaped and are considered harmless to the environment. In the future, reefs could be built from biodegradable materials that provide temporary structures, which break down after specific time periods, like after successful colonisation has taken place. Marine scientists and engineers are looking into creating artificial reefs using 3D-printers to design structures that optimise efficiency and that can be adapted for their specific environment.


The picture above shows 3D-printed reef structures, which were deployed near the Marmara Islands for Türkiye's first artificial reef project using this technology. A total of 160 of the 280 reefs in the project were created using 3D printers.


Other Innovative Solutions
Nature-based solutions is defined by the European Commission, as cost-effective methods that draw inspiration from and are supported by the natural world. Another example of a nature-based solution that aims to protect coasts and boost biodiversity is the planting of red mangroves (Rhizophora mangle). These salt-tolerant trees have intertwining roots (pictured below) that act as a natural shield against waves, thus protecting coastlines from erosion. These plants also provide shelter for smaller fish and crustaceans.  


Get Involved
If you would get involved in similar scientific projects that I have been a part of and learn many different aspects of coastal protection, biodiversity promotion, research and policy, you can contact Jon Christian Svendsen - senior scientist at DTU-Aqua (jos@aqua.dtu.dk). Jon can help you get involved in many projects across Denmark and its surrounding waters.



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