Can Concrete Save Our Coral Reefs?
The life cycle of concrete is a spectacular one. From its humble beginnings as mere gravel, sand, and cement it is transformed into expanses of surface area as far as the eye can see and looming skyscrapers as high as the eye can see. Inevitably, however, what goes up, must come down. And what is laid down, must come up. Sometimes that means going way down…even below the surface of the sea.
As concrete reaches the end of its life as a building or surface material, it is routinely recycled. There are many mundane, but quite worthy, reuses. Often, used concrete is ground down and sorted to be reused in new projects, permeable foundations, and similarly practical applications. It’s all very predictable and responsible and goes a long way toward reducing waste in landfills.
However—as is typical in the world of concrete—there exists a more exciting and innovative way to reuse concrete. And it involves schools of tropical fish, colorful crustaceans, and sprawling coral.
As the ocean faces various crises waged against its often fragile ecosystem, the marine community has made various attempts to aid the coral reefs. This has included the sinking of huge masses of that which can be sunk, including decommissioned ships, thousands of tires, old cars, pvc pipe, and even train cars. Some of these endeavors have been successful; for instance, the steel ships tend to acclimate well to their new ocean life, providing a safe harbor for all sorts of oceanic life. Others have been abject failures, such as the tires which proved not only to release toxins, but were also too lightweight to stay put.
You may not be surprised to learn that recycled concrete has emerged as a clear winner in supporting ocean life. Thanks to its simple, clean ingredients it nicely mimics the natural limestone qualities of coral and allows and encourages regrowth on its craggy surfaces. The weight of the concrete means it settles in and stays secure despite the constant movement that surrounds it. And the varying sizes and shapes of concrete chunks deposited on the ocean floor provide new dwellings for a multitude of ocean life. Flora and fauna that prefer to nestle down in tiny spaces and those who live more freely, closer to the surface, all find a comfy spot.
Constructing an artificial reef with concrete is a big undertaking, involving careful screening and cleaning of the material and much research on optimal placement of each chunk. When those details align, the pieces are loaded upon a barge that includes machinery for getting the heavy pieces offloaded and dropped into place. Once gravity has its way and the pieces have settled in, they are checked periodically by marine scientists to ensure the new habitat thrives.
A huge bonus to these concrete reefs is this: Small seedlings of coral can be grown on concrete in labs and then transferred to the underwater concrete landscape. This helps repopulate the coral and could help regrow our lost coral reefs. This is great news for our oceans—where coral lives and grows, so does rich, biodiverse marine life.
At Black Diamond Paving & Concrete, we prefer to do our concrete work without a wetsuit and diving tank. But we do love working with such fascinating materials that serve to enhance and better our environment for years to come. When solid materials meet innovation, the sky (or the ocean floor) is the limit.