Arianne Dalton couldn't see the muddy bottom of the South River, which is exactly why she was standing waist-deep in the water holding a rock covered with baby oysters.
"You just have to feel for the edge of the rocks and where the land starts," said Dalton, who enjoys sailing on the bay. "It's our environment, where we live. ... I've seen it degrade and I want to do my part to help it out."
Dalton, an Annapolis resident, and about a dozen other volunteers took the plunge for the environment Monday evening at Edgewater Beach, adding about 680 rocks caked with 2-month-old oysters to the river bottom to create a reef in hopes of improving water clarity and quality.
The project, organized by the Chesapeake Bay Foundation and the South River Federation, is the third effort of its kind in Anne Arundel County. The Naval Academy seawall and the breakwaters at the CBF headquarters in Bay Ridge also have man-made oyster reefs.
At one time, oysters were so plentiful in bay waters that they were known as "white gold." Capt. John Smith sailed the waters in early 17th century and is said to have noted that the waters were so thick with oysters that it was difficult to navigate his ship.
Over the past century, disease, pollution and over-harvesting have wiped out 96 percent of the bay's native oyster population, according to CBF estimates.
The foundation grows and plants millions of oysters every year and runs an oyster gardening program to boost the dwindling oyster population.
About 36,000 were planted Monday, about six inches below tide, to protect the oysters from exposure to freezing winter temperatures.
"As the oysters grow up, they will filter water and provide nesting places for bait fish, for blue crabs and mud crabs," said Jennifer Pitz, CBF oyster gardening coordinator. "They will cover the breakwaters and live here."
An adult oyster can purify as much as 60 gallons of water a day, and cleaner water means more sunlight for the river bottom. More clarity means more grasses thriving at the bottom, more oxygen and more life.
Over the past 50 years, South River underwater grasses have shrunk from 500 acres to 15, said Drew Koslow, the South River riverkeeper.
"The oysters turn the breakwaters into living things," he said. "The whole cycle has been broken by the way we live on land, but the oysters will make the water clear again."
John Flood, project designer, consultant manager and founding member of the federation, said of the effort, "We're putting the 'live' in living shoreline."
The oyster project and move to create a living shoreline at the South River complements a May 2006 project on the same site that added 200 tons of rock and sand to create a beach and break up wave energy.
Grassroots, volunteer efforts such as Monday's will be crucial to beating back environmental damage because funding for and attention to the problem at the federal and state level has at best stagnated, said Will Nuckols, a marine biologist who works for the federal government. He said agencies are doing what they can but that more helping hands are needed.
"We have to increase dramatically the number of people who are working on the environment," said the Annapolis resident who swims in the South River almost every day. "It has to start with these folks so that decades from now, they can educate people who have zero interest in the environment. This is the way to make progress."
Such is the aim of Myrtha Allen, a ninth-grade biology teacher at Patterson High School in Baltimore who set down about a dozen rocks flecked with bronze- and silver-colored oysters as part of the project.
In the classroom, her lessons often veer to issues of water quality and drinking quality, and the Chesapeake Bay. Allen's students have expressed concerns about water pollution, and she said her efforts to stem the tide of environmental harm will encourage them to act.
"When school starts I can tell my students that I did a service learning project and if I can do it, they can do it," she said. "It makes a difference for them to know that their teacher is involved in serving the community and the environment."
For information on gardening workshops call 410-268-8816 or visit www.cbf.org.