Call it Frankenreef.
The University of Hawaii will be awarded up to
$25 million by the Department of Defense to design and build a hybrid coral reef that aims to protect the coastline from the growing impacts of flooding, erosion and storms.
The part-man-made, part-natural reef structure will be installed at a yet-to-be-determined site on the coast of Oahu in a project funded by the DOD’s Defense Advanced Research Projects Agency.
Once finished in five years, the hybrid reef will stretch over 325 feet and be designed not only to dissipate wave energy, but provide habitat for corals and other reef life.
To help spark life into the structure, the Hawaii scientists plan to test and deploy an array of new technologies that aim to accelerate the health and growth of the corals that will be attached to the base framework.
“We’re trying to kick-start a living, growing coral reef,” said Rob Toonen, Hawaii Institute of Marine Biology professor and lead investigator for adaptive biology.
The groundbreaking project is being dubbed Rapid Resilient Reefs for Coastal Defense — or R3D — a joint effort between UH Manoa’s School of Ocean and Earth Science and Technology and the UH Applied Research Laboratory.
UH was one of three teams across the country
selected to work for the DoD agency’s Reefense project, which seeks to develop “self-healing, hybrid biological, and engineered reef-
mimicking structures” to address increasing incidents of storm surge and flooding.
The University of Miami will work on coral reefs in the Atlantic Ocean, while Rutgers University will focus on oyster reefs on the Gulf Coast.
According to DARPA, storm surge and flooding continue to devastate coastal areas around the world despite prevention efforts such as constructing concrete breakwaters. The Reefense program, the agency says, is an effort to try a new solution that doesn’t involve hardening the coastline.
Natural coral reefs are known to provide substantial protection to shorelines, absorbing and dissipating energy from storms and waves. But shorelines with insufficient reef coverage will be especially vulnerable in the years to come as climate change causes sea levels to rise.
In Hawaii at least 20 UH researchers representing five labs will work in partnership with experts from Florida Atlantic University; Scripps Institution of Oceanography at University of
California, San Diego; and Makai Ocean Engineering on Oahu.
Ben Jones, R3D principal investigator and director of ocean science and technology at UH’s Applied Research Laboratory, said he knew the university had the expertise, but it was still a challenge assembling the team.
“It’s not just biology. It’s not just ecology. It’s not just engineering. It’s putting all of those things together,” Jones said.
As planned, the hybrid reef will be constructed with a base of perforated, thin-walled concrete structures, described as low-cost efficient energy dissipators, that will be anchored to the seafloor.
Coral fragments from known heat-tolerant colonies and other local corals will be attached to concrete modules, where they will grow and eventually cover the base structures.
The finished product will be designed to function like a typical fringing reef, with a fore reef along the makai slope, a reef crest that absorbs much of the wave energy and a protected back reef that harbors more delicate species.
Having a diversity of life take over the structure is essential for allowing the system to self-heal and keep pace with sea level rise over time — just like a normal coral reef, officials said.
To push the process along, the scientists plan to try a number of novel technologies and techniques:
>> 3D design and biofilm chemistry to attract coral larvae and discourage algae growth.
>> Supplemental feeding for bleached corals.
>> Shading and the production of bubbles in the water column to protect and cool the reef in the early stages of reef development and during marine heat waves.
>> Piping in sounds of a healthy reef to attract organisms that help coral grow. Studies have shown that some fish that eat coral-killing algae are attracted to the sounds of a healthy reef.
Jones said the project will conduct small prototype testing in a wave flume on the Manoa campus. It will continue with scale-model testing in a larger wave flume at Oregon State University.
The exact location of the actual hybrid reef has yet to be determined, although the leading candidate site appears to be on the Mokapu Peninsula near Marine Corps Base Hawaii in Kaneohe.
The plan, Jones said, is to start constructing the first half of the actual reef structure on the coast in 18 months to see how it performs. That will be followed by the installation of the second half of the structure.
Toonen said the goal is to have the man-made framework 100% covered with life by the end of five years.
“It should look like a baby reef,” he said. “In five years it will have increased its biodiversity of fish and invertebrates. If there are fewer species, then we’ve failed.”
Judging by the growth rate of natural coral reefs, he said, it will take 25 years for it to blossom into a full-grown, vibrant reef ecosystem.
Toonen said he’s excited about the project and feeling optimistic for its success.
“The idea of why I got into science was to do something good,” he said. “Most research is about ‘the sky is falling.’ This is an opportunity to put our money where our mouth is and do something about it.”
Jones said he’s hoping the project will lead to additional hybrid reef projects as one solution to protecting Hawaii’s shoreline infrastructure. He added that the state Department of Transportation, which maintains many miles of coastal roads, has already taken an interest in the effort.
“It’s an ambitious project and it may not succeed,” Toonen said. “But we will learn a lot and expand our knowledge for the future.”
