Local school students have concluded the Eclipse-headquartered Nansemond River Preservation Alliance’s inaugural oyster gardening project by planting about 35,000 of the water-rejuvenating mollusks.

Alliance Education Committee Co-Chair Karla Smith said students from 10 Suffolk and Isle of Wight elementary, middle and high schools learned about improving the health of the river, getting their hands satisfyingly dirty in the process.

“They get a hands-on experience in dealing with the oysters and learn stewardship of the river,” she said.

Students delivered the oysters to two sites by boat during field trips and the alliance’s River and Creek Fest at Bennett’s Creek Park on June 2.

They had raised the baby oysters since October in floats tethered to docks and other structures.

The alliance held two events in August to train teachers leading the groups, who built about 20 “Taylor floats” — mesh baskets suspended from rectangular PVC-pipe frames, inside which the oysters live and grow before being left to fend for themselves.

“The mesh bag protects the baby oysters and the float keeps it from resting on the (river) bottom,” Smith said.

“The water flows through and oysters feed on plankton and phytoplankton, and they’re protected from predators.”

Over the growing season, the floats were pulled monthly and the oysters taken to participating schools for scientific analysis.

John Wass, Smith’s fellow co-chair on the Education Committee, said students used different instruments to check things like water salinity, water clarity and temperature, and also removed dead oysters.

Students learned about math, measurement and new vocabulary, Wass said, while improving their understanding of the river ecology and becoming better citizens.

Smith said, “The whole idea is science becomes real. The children get so involved and they are really a part of what’s going on, not just passive observers.

“The more opportunity they have to handle these oysters … the more interested they are going to be” when they hear about environmental issues affecting the Chesapeake Bay.

Experts say that when John Smith arrived, the oyster population could filter the entire bay in one week. But 400 years later, it takes an entire year.

Oysters are being killed by two diseases, MSX and dermo, and have been overfished for hundreds of years, Wass said.

“One hundred years ago, the natural resources in this country were considered unlimited,” he said. “They didn’t know any better, they didn’t think they would ever run out.”

Two separate sites were selected to plant the oysters. About 33,000 were submerged at a spot on the Nansemond, while the other 2,500-odd have been planted on an intertidal reef in Chuckatuck Creek.

Morbidity rates between the two sites will be compared to gauge how oysters survive in areas that become regularly exposed with the tidal cycle against being entirely underwater.

The alliance funded the project this year with a Virginia Environmental Endowment grant and has secured funding for next year from the Chesapeake Bay Restoration Fund.