CAMBRIDGE -- In a county sometimes described as being half water, it's not surprising that lanky 13-year-old Gary Phillips likes to spend an occasional afternoon fishing in the little inlets and ponds so plentiful here.
Higgins Millpond used to be a favorite -- the narrow inland pond is the headwater of the Transquaking River, one of the Chesapeake Bay's many tributaries.
But these days, when you find Gary by the shore of the pond, it is likely that instead of a hook, he will be lowering a flat white disk at the end of his line into the water.
Gary's testing the waters, so to speak.
The small saucer-like object called a Secchi disk helps testers like Gary gauge water clarity, a key measure of the pond's healthiness.
These days Gary, like an increasing number of children on the Eastern Shore, views the bay watershed through the eyes of the environmentalist. Along with about 30 other students at Mace's Lane Middle School, he's become part of a volunteer corps of "Riverwatchers," dedicated to monitoring water quality.
Gary has been collecting data for a year.
"When I started on the program, I thought the bay was in great condition. You could catch fish there. You could catch crabs there," said the eighth-grader.
But now he's not so sure.
There's been an algae bloom on one side of Higgins Millpond for several months now. Gary knows what that means -- elevated levels of nitrogen, phosphorus and possibly ammonia. It means the water is not healthy.
"It's just a matter of interpreting the data," he said.
Up and down the shore, students as young as 11 are talking knowledgeably about nutrient levels, dissolved oxygen, phosphate and nitrogen levels, salinity and temperature of the bay. They use sophisticated instruments like hydrometers, spectrophotometers and colorimeters to measure chemical levels down to specific parts per million. And they communicate their findings by computer, zipping their data in their Apple computers by modem into a statewide bulletin board.
They are part of a growing number of students who are learning about disciplines as varied as statistics, biology and chemistry by learning about the bay.
It is a trend that state education policy is trying to ride. Last year, the Maryland State Board of Education passed a bylaw mandating that all schools teach information about the environment, using the Chesapeake Bay as an example. The bylaw took effect last semester.
Counties have augmented their environmental curriculums and teacher training with grants from a $125,000 state fund set aside for environmental education.
Here on the Eastern Shore, it is difficult to ignore the bay when it's right outside the back door, said George Radcliffe Jr., a teacher at Mace's Lane Middle School.
Mr. Radcliffe, a transplanted Baltimorean, began the river monitoring program at Mace's Lane Middle School more than three years ago. He said students told him they wanted to do more than go out once or twice a year on brief field trips.
"The Chesapeake Bay is one thing we all have in common," Mr. Radcliffe said, talking in a classroom festooned with Greenpeace posters and Far Side cartoons. Students wanted to know what was happening to it.
So Mr. Radcliffe managed to secure a grant from the Chesapeake Trust and set up a water quality lab at the school.
An Apple computer with a hard disk sits on one slate-topped table. Scientific equipment -- such as colorimeters, spectrophotometers and their like -- were on another. The
drawers were filled with chemicals and testing kits.
In the lab, Gary and several classmates were completing tests on his latest sample, a sickly green jar of water from the pond.
One girl poured a test tube full and added some chemicals that turned the water an inky black. Then she dropped in a solution of manganese sulfate until suddenly the water turned clear.
"That means the oxygen level is about 9.8 parts per million. About normal," she said.
But other measures showed that the levels of the nutrients nitrogen and phosphorus are higher than they should be.
Gary said he thinks the source is a rendering plant that pours some wastewater into the pond. Algae feast on the nutrient-laden water.
At 13, Autumn-Lynn Harrison is the dean of a group of bay watchers who have been monitoring Dorchester County's water quality for more than three years.
She recalled that when she was young -- 7 or 8 years old -- she didn't know much about the bay.
"I would just look at the water, but I didn't know about any of its problems," she said. "But the more you know, the more you get hooked on it. It's hard to stop caring."
Now she can tell the effects of a small change in nutrient levels. Phosphates, she explained, can cause blooms of algae. When the algae die, they use up oxygen, killing fish and other underwater life.
Teachers and other adults say they have noticed that children -- even as young as 7 or 8 -- have a surprisingly sophisticated view of the bay.