Self-repairing oyster reefs will help protect coastlines

The University of Central Florida (UCF) has recently been co-opted to participate in a $12.6 million Defense Advanced Research Projects Agency (DARPA)-funded project called Reefense, which aims to develop self-healing, hybrid biological and engineering reef-mimicking structures. These self-repairing oyster reefs will help mitigate coastal flooding, erosion, and storm damage that currently threaten civilian and Department of Defense (DoD) infrastructure and personnel. 

Reefense plans to foster the growth and restoration of calcareous reef organisms – such as corals or oysters – through the use of custom wave-attenuating base structures. These structures will aid in self-healing and the accommodation of sea level rise over time. 

Additionally, the system will draw in other organisms vital to the maintenance of a thriving ecosystem. The incorporation of adaptive biology, without the use of genetically modified organisms, will also boost the resilience of corals and oysters against disease and temperature stress, thereby ensuring compatibility with a changing environment.

The Reefense project currently consists of three teams led by Rutgers University, the University of Miami, and the University of Hawaii. While Rutgers is focusing on oyster reef, the other two universities will work with corals. The UCF researchers – led by Kelly Kibler, an associate professor of Ecohydraulics – will monitor the pre- and post-implementation of the oyster reef structure and assess how the reef and habitat mosaic influence sediment transport near the shoreline.

“We’re not only focusing on the oyster reef, but we’re also bringing in a mosaic habitat concept. So, we’re not only working with one species but recognizing that multiple species that inhabit the intertidal zone work together to create further resilience,” Kibler explained. “This type of natural infrastructure design project is important especially to a state like Florida that is vulnerable to climate change impacts and rising sea level.”

The overall project consists of three phases including iterations of designing, implementing, and monitoring the structures. The UCF team – which will receive about $800,000 for their collaboration in the project – is currently in Phase 1 and is set to implement the first structure in 2024, as part of Phase 2.

According to Kibler, the long-term success of the reef will depend on the recruitment and survival of the oysters. If they turn out to be successful, these structures could be used in various regions in Florida and elsewhere in the world within the range of oysters.

“We hope to have a cost-effective, transferable design that would be taken up by communities, homeowners and landowners,” she concluded.

Why are oyster reefs important?

Oyster reefs provide numerous ecological and economic benefits, and they are considered important for a variety of reasons:

Biodiversity Support

Oyster reefs create complex habitats that provide shelter and breeding grounds for a multitude of marine species, including fish, crustaceans, and other shellfish. This helps to maintain high levels of biodiversity in the marine ecosystem.

Water Filtration

Oysters are filter feeders, meaning they extract plankton and other particles from the water. This process can significantly improve water quality by reducing excess nutrients, particulate matter, and harmful algal blooms.

Shoreline Protection

Oyster reefs can act as natural breakwaters, reducing the impact of waves, preventing erosion, and stabilizing shorelines. They can also buffer the effects of storm surges, helping to protect coastal communities.

Carbon Sequestration

Oysters, like other shellfish, help to remove carbon dioxide from the water, converting it into their calcium carbonate shells. This process aids in mitigating the effects of climate change.

Economic Value

Oyster reefs support commercial and recreational fisheries by providing habitat for valuable fish and shellfish species. The oyster industry itself is a significant economic contributor through the provision of jobs and seafood products.

Education and Research

Oyster reefs can serve as living laboratories for educational and scientific research, providing insights into marine ecology, habitat restoration, and climate change.

Despite their importance, oyster reefs are among the most threatened marine habitats globally due to overharvesting, disease, pollution, and habitat destruction. Restoration and conservation efforts are crucial to preserving these valuable ecosystems.

How will sea level rise impact coastlines?

Sea level rise can have significant impacts on coastlines. Here are some of the ways in which rising sea levels can affect coastal areas:

Coastal Erosion

Higher sea levels contribute to increased erosion of coastlines. As the water reaches farther inland, it erodes beaches, cliffs, and dunes. This can lead to the loss of valuable coastal land and damage to infrastructure, including buildings and roads.

Flooding

Low-lying coastal areas are at a greater risk of flooding as sea levels rise. Even small increases in sea level can lead to more frequent and severe coastal flooding during storms and high tides. Saltwater intrusion into freshwater sources can also occur, impacting drinking water supplies and ecosystems.

Wetland Loss

Coastal wetlands, such as marshes and mangroves, are highly vulnerable to sea level rise. These ecosystems act as natural buffers, absorbing and dissipating wave energy. However, as sea levels rise, these areas can become submerged, leading to the loss of important habitats and a decrease in their protective functions.

Displacement of Communities

Rising sea levels can force the relocation of coastal communities due to increased flood risks and erosion. Some small islands and low-lying coastal regions may become uninhabitable in the long term, leading to the displacement of populations and potential social, economic, and political challenges.

Impact on Infrastructure

Coastal infrastructure, including ports, harbors, and coastal defense systems, may be affected by sea level rise. Structures designed to withstand current sea levels may become inadequate, requiring expensive upgrades or adaptations to mitigate the risks.

Ecosystem Changes

Rising sea levels can disrupt coastal ecosystems by altering habitats and ecological processes. Changes in water salinity, flooding patterns, and erosion can affect coastal plants, animals, and biodiversity. Some species may be forced to migrate or face habitat loss, leading to ecosystem imbalances.

It is important to note that the extent of these impacts will depend on various factors, including the rate of sea level rise, the geomorphology of the coastline, and human interventions such as coastal management strategies and adaptation measures. Efforts to mitigate and adapt to sea level rise, such as coastal defenses, beach nourishment, and land-use planning, can help reduce the impacts on coastlines and coastal communities.

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By Andrei Ionescu, Earth.com Staff Writer

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