Oyster reefs are essential for healthy coastal ecosystems, filtering large volumes of water and improving water clarity and quality. In the Indian River Lagoon, where oyster populations have decreased as a result of overharvesting and habitat degradation, human-made oyster mats are a helpful tool in the fight to restore the estuary’s health.
But the mats are traditionally made using plastic mesh, a material which breaks down into smaller pieces that marine organisms ingest. These microplastics are an increasingly alarming problem across the globe, especially in large bodies of water.
Florida Tech assistant professor of Oceanography Kelli Hunsucker, along with professor of Oceanography and Ocean Engineering Geoffrey Swain, associate professor of Ocean Engineering Robert Weaver, and graduate student Afanasy Melnikov, are the recipients of a $40,000 grant from the Brevard County Tourism Development Council to investigate a new approach to oyster restoration in the lagoon.
They are exploring alternatives to the plastic mesh, looking closely at using electrically charged steel mesh instead. The electricity causes a rise in the pH levels, which results in calcium carbonate depositing on the steel mesh, similar to reef substratum or limestone. It allows for increased survival of oysters and growth through reinforced substrate stabilization. All of this allows for a more environmentally friendly approach to oyster rehabilitation.
The idea to use the charged mesh came from Swain, who is familiar with the work done using this process in coral reef systems. The Florida Tech team tested various materials to see which mesh would allow for optimal calcium carbonate growth and now have test mats in the lagoon as they assess how much mineral growth is occurring on each version and the electrochemical properties for each. Phase two of the project will involve working with local partners to deploy test mats lagoon wide, including: Rib City at Grant Station, the Environmentally Endangered Lands (EELS) program, and a Florida Tech facility in Port Canaveral.
“Part of our focus is to restore the natural filter feeders which have been overfished in the lagoon. We need to increase the number of these organisms, like oysters, to help us combat the water quality issues and the algal blooms that we have,” said Hunsucker, the principal investigator in the steel mesh research. “But obviously, removing the muck, stopping fertilizer and grass clippings from going into the lagoon, those are all really important, so I think of it as a multi-faceted approach. Our project is one piece of the effort to restore the Lagoon”