Terra-cotta ceramics have been used for thousands of years, but a particularly 21st-century application gives the material an entirely new purpose.
Marine scientists and architects from the Swire Institute of Marine Science (SWIMS) of the University of Hong Kong (HKU) and its Robotic Fabrication Lab of the faculty of architecture, respectively, worked together to 3D print terra-cotta tiles that will act as artificial reefs. The result is a mesmerizing, organic swirl of line and negative space that reads like a burnt orange topographic map—and mimics the natural patterns of the coral itself.
Green Power attributes the decline to a combination of global warming, pollution, net fishing, and water sports. Researchers at HKU also cite bioerosion (gradual deterioration of coral habitat), coral bleaching, and partial mortality events (basically the rapid dying off of a species over a short time) due to red tide in 2015 and 2016, according to team member Vriko Yu. This is where manmade or artificial reefs come in—they help restore lost coral populations by reintroducing an environment amenable to regrowth—and they’ve been made of everything from purposefully submerged shipwrecks to cement sculptures.
While all the coral tiles are identical in this pilot study, the team will use different designs in the next iteration to figure out how they affect the species. The designs can also be specific to the environment and underwater conditions where they are placed; for instance, the team designed these tiles to prevent sedimentation buildup, a major problem in Hong Kong waters.
And since the tiles interlock, they appear as though the ocean floor has been retiled and renovated. It has in some sense. The reef tile design provides a “structurally complex foundation,” according to an HKU statement, which gives coral fragments lots of nooks and crannies to anchor onto, and prevents sediment buildup, which is a major threat to corals, they say.
The team placed the reef tiles seeded with coral fragments over about a 430-square-foot area across three sites within Hoi Ha Wan Marine Park in Hong Kong this past July. Researchers will monitor coral growth on the tiles over the next two years. This is just the beginning of the project: The team plans to develop new tile designs and further expand seabed restoration in the area.