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Coming Out of His Shell
David Lewis’s after-school job is saving the Chesapeake Bay, one baby oyster at a time.

When you’re raising a budding ocean scientist, you have to be prepared to make some sacrifices. For the family of 17-year-old David Lewis of Yorktown, Virginia, one appreciable sacrifice has been the kitchen counter space that once was available for sandwich-making or vegetable-slicing but is now taken up by a 20-gallon glass aquarium inhabited by a colony of spiny, green, contentedly indolent sea urchins.

As he proudly shows them to a visitor, Lewis explains that he’s been testing the effects of temperature on sea urchins’ ability to flip over and right themselves when they fall off the side of the tank, where they like to congregate. But in truth it’s another species of aquatic organism that has most captured the fancy of this Eagle Scout and high school senior.

A short walk through his family’s suburban backyard ends at a wooden boat slip on Lambs Creek, a gently rolling tributary of the 12-mile-long Poquoson River, which flows out to the Chesapeake Bay. Lewis guides his visitor to the edge of the slip and pulls at a rope he has secured to a piling. Up comes a homemade float crafted from metal wire and PVC pipe, about the size of a mid-range flat-screen TV. Its bottom is pockmarked with barnacles; nestled in its basin—along with a few guppies and one rather startled crab—is a rectangular mesh bag. Inside the bag are roughly 1,000 Eastern oysters.

Lewis is now in his fifth year as a volunteer oyster gardener, a responsibility he first assumed as a 13-year-old Boy Scout in search of his next merit badge. Near the end of each summer, the Chesapeake Bay Foundation sends him home with a shipment of baby bivalves—each no bigger than a fingernail—which he then spends the better part of a year tending. Once these oysters have had a chance to grow up a little under Lewis’s watchful eye, he and CBF members deliver them to a state-protected sanctuary reef in the bay. Thanks to their year of being cared for, they’re healthier and sturdier than juveniles that were placed on reefs directly from hatcheries.

As he frees the oysters from their bag and gives it a good scrubbing, Lewis explains why he doesn’t mind removing caked-on oyster excreta from wire mesh when he could be playing video games. “An adult oyster is capable of filtering 50 gallons of water per day,” he says. As water flows through their slightly opened shells—and with it plankton, sediment, and algae-generating nitrogen—oysters, he notes, operate as highly efficient strainers for their habitats.

But because of overharvesting, pollution, and disease, oysters have almost disappeared from the Chesapeake Bay. Today their population hovers between 1 percent and 2 percent of historical levels. “Back in the 1600s, when John Smith came over to colonize the East Coast, he actually got his boat stuck,” says Lewis. “There were so many oysters that he was scraping the bottom of his hull.” In an effort to replenish the waters, the Chesapeake Bay Foundation and other groups have planted hundreds of millions of oysters onto 1,500 acres of oyster reefs since 2001.

In addition to performing routine cleaning and maintenance, Lewis must keep an eye out for hungry crabs, check for signs of disease or parasites, and, in the event of hurricanes or major storms, move his oysters to safety. (“They do just fine in the garage under a wet towel for a couple of days,” he says.)

He also conducts experiments. In one, he learned that when aqueous pH levels drop—most typically as the result of acidification brought on by CO2 absorption—“it definitely lowers filtering rates. Ocean acidification is right up there with overharvesting” as an obstacle to oysters’ long-term recovery, he says.

When Lewis heads off to college next year, he hopes to study biology with a focus on marine science. By his first day of class he’ll be able to say that he has already foster-parented more than 5,000 oysters: protecting them, nurturing them, ushering them into adulthood.

But never naming them. “Some other oyster gardeners do that,” Lewis says, grinning at the suggestion. “I don’t.”

On the other hand, he says, “I don’t eat them, either.”

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Jeff Turrentine is OnEarth's articles editor. A former editor at Architectural Digest, he is also a frequent contributor to Slate, The Washington Post, The New York Times Book Review, and other publications. MORE STORIES ➔