Japanese building giant Taisei Corp is using techniques used in the construction of underwater tunnels in turbulent environments to revive local ocean ecosystems imperilled by climate change.
The company has used its own proprietary technology to place 600 mortar blocks on the sea bed off Miyakojima island in Okinawa Prefecture, in order to serve as seeding beds for coral larvae.
While the placing of inert structures on the seabed to foster the growth of a life form as hardy as coral may appear to be an elementary task, it required the use of sophisticated methods to assess tidal movement and determine the locations where coral larvae were likely to alight.
In order to achieve this, Taisei Corp made use of its proprietary tide prediction technology, which it has already applied to the development of a tunnel across in Turkey across the Bosphorus Strait to link the Mediterranean Sea with the Black Sea.
Taisei was able to build an undersea tunnel in the strait by using its tide prediction technology to gauge the movements of the powerful and complex currents that traverse it. By anticipating the strait’s tidal movements, the Japanese construction giant was able to time the deployment of the 11 separate sections of the tunnel with little concern about disruptive water movement.
It was then able to connect the disparate section on site at depths of up to 60 metres in conditions of relative safety.
In the case of the Miyakojima Island coral reef project, Taisei was able to use the stream prediction method to determine at which points coral larvae were likely to fall in the island’s adjacent waters.
The company then deployed a series of 600 mortal blocks at these sites, where they are best-positioning able to reap the coral larvae as they underwater eddies channeled them towards these locations.
The method has proved as successful at fostering coral growth as it was at helping to build tunnels in hazardous waters. So far, a total of 42 coral larvae have settled on the blocks, growing to maximum sizes of four centimetres.
Taisei officials say the mortal blocks seeded with the nascent coral reefs can now be shifted to locations with preferable environmental conditions in order to best foster their future growth.
“We hope to contribute to recovering these lost natural resources as much as possible,” said Kazunori Ito, chief of the hydraulic and environmental engineering research section of Taisei’s civil engineering research institute.
The construction giant now plans to sell the coral restoration method to government bodies and other organisations concerned with the restoration of ocean environments.