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Protecting Shorelines

A new job for our versatile oyster 
Horn Point scientist Matthew Gray, front, removes seed oysters from a holding pen. He is helping oversee an experiment on whether constructed concrete oyster reefs, right, can help stave off rising sea levels.
      What can’t an oyster do? It builds communities for underwater life, it filters its surrounding waters and feeds many species, including humans. Now scientists at the University of Maryland’s Horn Point Laboratory in Cambridge are putting it to work to help fight shoreline erosion.
     That’s a problem worsened by climate change, which has led to a rise in water levels in the Bay. Indeed, scientists say the Chesapeake has some of the fastest-rising sea levels in the United States. 
      Next to an eroding shoreline at the Lab, researchers are constructing oyster reefs as breakwaters against waves hitting along the shoreline. “This is like a living laboratory, because unfortunately, we had some erosion,” said Horn Point scientist Matthew Gray. “So we are trying to apply this technology to see if it can stop the erosion right on this campus.” 
      The reefs are constructed from a series of interlocking concrete cinder blocks, called oyster castles, onto which have been placed millions of oyster larvae. The researchers use late-stage larvae that are expected to set onto the blocks within minutes of exposure to the water. To assure the attachment, they surround the structures with silt fences.
     Once attached, these juvenile oysters, known as spat, will start to feed, putting most of their energy into growth. Oysters typically grow up to an inch each year by absorbing minerals from the water and nutrients through their filter-feeding on suspended particles, like algae. As a result, growth rates may vary depending upon the salinity and quality of the water.
      The oyster reef experiment is based on the idea that constructed reefs of living, growing shelled organisms may mitigate the effects of rising seas.
      “We want to prove that a living reef, one that is alive and growing, can keep pace over time with rising water levels,” said another scientist, William Nardin. 
     This project is funded in part by Dominion Energy and the Palmer Foundation. The researchers are also working with the National Wildlife Federation to study the effects of these structures on water quality. 
      Horn Point Laboratory, the site of the experiment, maintains one of the largest oyster hatchery facilities on the East Coast. The hatchery produces a variety of oyster larvae for use in research, education and oyster restoration.