The latest troubling report on Australia's Great Barrier Reef has conservationists and the scientific community on alert, as researchers are trying to find answers to the grave bleaching problem affecting the world's corals.
After last month's online edition of the journal Nature featured an alarming study on the dire effects of ocean acidification, scientists have been surveying Australia's reefs only to discover they face possible extinction. Half of the world's coral reefs have already faded in the last 30 years and future estimates are even more somber: 90 percent are in danger of being wiped out by 2050.
Efforts to combat the coral bleaching crisis are making researchers grasp for any potential reef-saving idea and, as proven many times over, when brilliant minds come together creative solutions emerge.
In addition to marine life conservation programs, such as the 50 Reefs Project aiming to preserve the remaining unaffected coral reefs, salvation may come via technology, as scientists are beginning to explore the advantages of artificial reefs.
3D Printing Technology Offers New Hope
The notion of artificial reefs is not a novelty in itself. In previous restoration attempts, scientists have tried to recreate lost reefs from sunken shipwrecks, and even other types of materials - including plastic, concrete blocks, old tires, and cars, not to mention the famous Christ statue of Florida Keys - have been sunk to the ocean floor in hopes to invite in marine wildlife.
Since some of these experiments have successfully managed to blend in with their surroundings, attracting fish and coral polyps and enabling them to thrive, researchers are looking into ways to improve this favorable outcome and provide a more effective lifeline for marine creatures.
One idea that seems to stand out as the most beneficial is supplementing dying reefs with 3D-printed versions that are built to better withstand climate changes and are less likely to be destroyed by the effects of ocean chemistry.
Unlike other types of artificial reefs, 3D-printed variants can faithfully replicate the texture and architecture of natural reefs, providing protection, passageways, and camouflage for fish that are trying to feed or elude predators.
This technology's biggest advantage is that it allows the perfect mimicking of a reef's internal and exterior structure, all the way to the different natural angles that cast shade or light underwater. In other words, it features the optimal conditions for wildlife to make a home and prosper.
How 3D-Printed Corals Are Made
In nature, coral reefs are built by colonies of millions of tiny coral polyps, which attach themselves to different surfaces and to each other, in a symbiotic relationship with algae-like organisms. These organisms, called zooxanthellae, provide nourishment for the corals, while benefiting from their protection.
To meet with success, an artificially constructed reef must be able to support the life of both organisms, as well as other marine species.
Therefore, designing a natural-looking and functioning 3D replica is much like building an aquatic home for very specific inhabitants.
Reefs are living organisms that manage to make a life in harsh natural conditions, so mimicking their design and texture requires strong and durable materials. To build these artificial structures, scientists typically use a sandstone material with a minimal carbon footprint.
In a current project targeting the Monaco Larvotto Reserve, Boskalis - a Dutch maritime company working with the Prince Albert II of Monaco Foundation - has produced dolomite sand reefs weighing 2.5 tons each.
These fake reefs, measuring 6.5 feet in diameter and a little over 3 feet in height, individually took 13 hours to print.
Several Projects Already Underway
The first experimental installation of this kind was tested as early as 2012 in the Persian Gulf. Other 3D reefs are now being sunk in the Mediterranean, the Caribbean, and Australia, pending a monitoring period of a couple of years to measure their success rate.
More than granting shelter for marine species, the artificial reefs' main objective is to create alternative living spaces for coral polyps, which can expand the man-made structures and grow into new reefs if they successfully attach and multiply.
In the absence of coral polyps, the newly constructed reefs risk decay and erosion, and could crumble under the aggressive conditions in which these living structures normally exist.
Structural size, as well as the dimensions of each crevice within the artificial reef, also influences how many marine species will choose to occupy it.
"You are talking about a very complex environment, a complex animal with a lot of variations with each subspecies," explains Astrid Kramer, a Boskalis senior engineer.
"In the short term, we've seen a lot of positive momentum with certain species of coral. But remember, this is a drop in the bucket in a very, very large ocean," he adds.
