Photo: UCF
Photo: University of Hawaii
Photo: UCF
Photo: UCF
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Higher Education: Environment
Nature vs. Nature
The U.S. Department of Defense is partnering with universities in using oysters and corals to shield military bases from storms and rising seas.
To protect coastal military bases from sea-level rise and storm surge, the U.S. Department of Defense is tapping into the most powerful and enduring force on Earth: Nature.
The DOD’s Defense Advanced Research Projects Agency, DARPA, has contracted with three universities to develop structures that could defend multi-billion-dollar coastal military bases against nature’s destructive side.
With most of Florida’s 21 military bases located along the coast — including Tyndall Air Force Base, which was ravaged in 2018 by Hurricane Michael — what is coming to their rescue?
Oysters. And, it is hoped, corals.
Rugged oyster reefs and rock-like corals can diffuse wave action that steadily erodes a coastline or shreds it during storms. The problem is that there are few wild oysters and native corals left because of habitat degradation.
Enter “Reefense.”
“Despite previous efforts to implement storm mitigation solutions — including concrete breakwaters — damage due to storm surge and flooding continues to devastate coastal areas around the world,” DARPA announced last June while granting up to $45 million in R&D funding to the three universities. The Reefense program — engaging universities in Florida and elsewhere — aims to develop “self-healing, hybrid biological and engineered reef-mimicking structures to address the challenges,” DARPA said. Rutgers University in New Jersey is leading the work to engineer hybrid oyster reefs while the University of Miami and the University of Hawaii are charged with engineering hybrid coral reefs.
WSP USA is leading the engineering for the “mosaic oyster habitat” DARPA-funded project to create 20 acres of oyster reefs and 30 acres of saltmarshes in East Bay in Bay County. The company was instrumental in developing a “living shoreline” of plants and animals stabilizing a coastal section of U.S. 98 in Franklin County, where rock walls built to protect the site from erosion have repeatedly failed to prevent it from collapsing during storms.
Back to nature, sort of
Healthy, wild oyster reefs have been depleted largely by habitat degradation. Scientists and aquaculturists are trying to learn to cultivate oysters as seafood, but unlike wild oysters in healthy habitats, farmed shellfish do not thrive on their own.
Likewise, oyster reefs that once cleaned the water, provided habitat for other marine plants and animals and buffered shorelines from battering waves are no longer self-perpetuating. Marine scientists and the Defense Department are investing in hybrid reef technology that can re-establish oyster reefs to serve as natural infrastructure.
“It’s a relatively new idea to think about shellfish reefs as coastal protection. Now that we’ve figured it out, we can put nature back to work for us,” says Kelly Kibler, an associate professor of engineering at the University of Central Florida and a member of the DARPA/Rutgers oyster project team. She specializes in ecohydraulics — how water and sediment move and settle around living things in the aquatic environment — and says she is pleased that reefs are getting the respect they deserve.
“My prediction is Florida will become the hotbed of knowledge about climate change adaptation because we’re going to have to be. We’re going to have to be bold and try things that are high risk, high reward. We’ll learn a lot from doing it, and we’ll be a model for others that will unfortunately be following in our footsteps,” Kibler says.
“Ecologists refer to oysters as ecosystem engineers because just their presence alters the physical environment to make it more hospitable to themselves so they can grow and thrive. You can describe marsh vegetation also as an ecosystem engineer,” Kibler says. “When we build an oyster reef and our goal is coastal protection, we get a lot more: We’re also improving our water quality; we’re providing habitat for Florida’s amazing biodiversity; we’re tackling many different issues with the restoration of just one habitat type.”
Kibler and her UCF team are assessing a pilot site in East Bay ahead of helping the larger team design and install engineered structures on which oyster larvae can attach and grow into reefs. As part of the “mosaic” of the ecosystem, the team also wants the engineered reef to collect sediment deposits that grow seagrasses and marsh grasses, support water quality and marine life and dissipate wave intensity hitting shorelines. Also, unlike non-living structures, oysters reefs can self-heal after a storm or other damaging event.
Kickstarter for corals
DARPA granted the University of Miami Rosenstiel School of Marine, Atmospheric and Earth Science $7.5 million for initial-phase design and development of hybrid coral reefs to help protect vulnerable coastal regions in Florida and the Caribbean.
UM’s Andrew C. Baker, director of the Coral Reef Futures Lab at the Rosenstiel School and principal investigator on the corals project, says the DARPA/UM team will develop “next-generation structural designs” on which coral can take hold and grow into reefs.
“At the same time, we will also be testing new adaptive biology approaches to produce corals that are faster-growing and more resilient to a warming climate,” Baker adds.
Nicknamed X-REEFS, the work focuses on ways to protect Florida’s often densely populated, low-lying coastlines from storm surge and coastal flooding. It involves coralreef specialists from SECORE International, a leading conservation group in the field of coral restoration, and from the University of California, Santa Cruz; Pennsylvania State University; Johns Hopkins University, Texas A&M University; Florida International University; the University of Florida; the Florida Aquarium; and the Smithsonian Marine Station. Engineering firm AECOM supports X-REEFS with project management and engineering services.
Kibler and others say Florida is an ideal place to engineer and deploy technology that restores natural infrastructure such as oyster reefs, coral reefs and saltmarshes needed now more than ever. She is hoping that a boost in federal funding from the 2021 Bipartisan Infrastructure Law may propel the work.
“If we can really harness the power of evolutionary experience that’s embedded in these ecosystem engineer organisms, we can solve a lot of problems we have with traditional coastal infrastructure,” Kibler says. “Species that have been around for millennia, these are the smart technologies. The design lifespan of a natural infrastructure system could theoretically be, you know, forever.”
Mimicking Reefs
As the Department of Defense’s 1,700 coastal military installations worldwide face increased flood threats, the DOD’s “Reefense” project aims to build hybrid reefs that reduce the intensity of waves. Engineers and biologists are testing artificial structures on which oysters and corals can grow if conditions allow. The larger the reefs, the more they reduce wave-induced flooding.
