As it turns out, oysters remove nitrogen pollution from the waters of the Chesapeake Bay and other bodies of waters at rates that are higher than previously known, according to a new report by researchers at the Virginia Institute of Marine Science and the University of Maryland Center for Environmental Science.
Restored oyster reefs in the Bay can absorb up to 10 times more nitrogen –- which feeds algal blooms and low-oxygen “dead zones” –- than areas of the estuary without healthy reefs, providing new evidence that replanting and rebuilding oyster reefs can clean up the nation’s largest estuary, according to the study, “Denitrification and Nutrient Assimilation on a Restored Oyster Reef.”
“Our study showed that a successfully restored oyster reef can remove significant levels of nutrients from the water column,” said Lisa Kellogg, a researcher at William & Mary’s Virginia Institute of Marine Science. “We found that annual denitrification rates at the restored site were enhanced by an order of magnitude and that rates in August were among the highest ever recorded for an aquatic system.”
And oysters not only remove nitrogen pollution. They also filter out algae, and their reefs provide habitat for scores of other forms of life. As part of the research project, scientists examined a restored oyster reef in Maryland’s Choptank River that had 131 large oysters per square meter to an adjacent unrestored site that was suitable for restoration, according to a VIMS press release.
The restored reef provided habitat for almost 25,000 bottom-dwelling organisms per square meter compared to just over 2,000 organisms per square meter at the control site.
That’s 25,000 good reasons to support oyster restoration projects in the Bay.
To learn about the Chesapeake Bay Foundation's oyster restoration efforts, please click here.
To read the whole report in the Marine Ecology Progress series, click here.
By Tom Pelton
Chesapeake Bay Foundation
(Photo from the Chesapeake Bay Program)