The research vessel Rachel Carson cruises up the Wye River on Maryland's Eastern Shore. The ship's crew spends days at a time collecting sediment and water samples to understand the chemistry of the Chesapeake Bay.
Walter Boynton, a marine scientist with the University of Maryland Center for Environmental Science, studies the complex interactions between marine life and its watery — and often muddy — habitat. Once the country's richest estuary for both commercial fishing and marine wildlife, the Chesapeake Bay has undergone a steady and steep decline over the past several decades.
Technicians spend all day collecting sediment samples that are essentially "biopsies" of the bay's bottom.
Each sediment core is carefully removed and transferred to "incubators" where the mud and all the organisms in it are kept at the same temperature as the bay bottom.
Dead sediments contain few, if any, living things. These samples taken along the Wye River are relatively healthy. They harbor everything from bacteria to small mollusks — and sometimes even a fish or two.
Technicians and students aboard the Rachel Carson work in a small chemistry lab, measuring things like dissolved oxygen in the sediments and water. Low levels of oxygen — and sometimes a complete lack of oxygen — is an increasing problem in the bay.
Residue from a day's work lies at the bottom of a collection tube. It may not look very exciting, but knowing the condition of sediments from around the bay helps researchers pinpoint areas where work needs to be done to reduce harmful pollutants.
Boynton gets plenty of visitors aboard the Rachel Carson; it's a favorite assignment for students — as well as University of Maryland Center for Environmental Science staff — to get out on the bay.
A summer of sampling creates a map of sediment chemistry and a guide to the location of harmful pollutants and low-oxygen hot spots throughout the 180-mile-long Chesapeake Bay.
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America's largest estuary, the Chesapeake Bay, remains polluted and sick despite decades of clean-up efforts that cost billions of dollars. Now the Environmental Protection Agency (EPA) is working on a new plan to try yet again to save the bay. A draft of the plan is due out this week.
One thing the EPA still needs to do is decide how to spend its money; the bay is 180-miles long and fraught with many problems — pollution, overfishing, and overcrowding. For help, the agency is turning to scientists like marine scientist Walter Boynton of the University of Maryland Center for Environmental Science.
Boynton has spent decades studying the bay — especially the sediments under the water. That's where a lot of the bay's basic chemistry takes place.
Aboard the research vessel Rachel Carson, Boynton plies the Wye River, a waterway along the bay's Eastern Shore. "We've been basically making a map of what the sediments are doing to the water in Chesapeake Bay," Boynton says as his team of technicians and students lower a clanking hunk of metal over the side and down to the river bottom. It's a sediment corer. It takes a chunk of oozing mud from the bottom and is then hauled back up.
A Messy Job
It's a messy job — everyone's wearing waterproof coveralls — but it pays big dividends. These tubes of glop are like biopsies — they indicate where the bay is healthy and where it's dying. That will help determine where the EPA needs to crack down on pollutants.
Boynton says dead sediments are easy to identify. "They almost feel as if you were making a pot of jello, and it hasn't quite congealed yet."
Dead sediments are basically mud with little or no oxygen. Clams and worms and microscopic plants at the bottom of the food chain — down in the mud — need that oxygen. But the bay is starved for oxygen. What it has instead are nitrogen and phosphorous. Way too much of it.
The extra nitrogen and phosphorous come mostly from sewage, cars and fertilizer. They act as "nutrients" for algae, which gorge on them and grow into huge floating blooms. When the algae die and decompose, that sucks oxygen out of the water. And that's deadly.
"The key issue in the bay program is [to] reduce the amount of nitrogen and phosphorous and dirt getting into the bay. That's one of the things I do, is build nutrient budgets," says Boynton. "We frankly need to know where does this stuff come from, how long does it hang out here, and where the heck does it go."
Mapping Pollution Hot Spots
Biologist Kristin Politano taps a canister of sediment to get oxygen bubbles to rise. She learned about nutrient pollution in Florida, but in some ways it's the same in the Chesapeake. Scientists can map the pollution hot spots, but someone has to follow them back to source to fix the problem.
"It all boils down to what we're actually putting into the watershed," says Politano. "People get upset about what's going on in the bay. What they have to realize is that a lot of the problems are coming from the upper watershed themselves. You have to look at restoring headwaters and streams, and rivers and things like that before you are going to see an improvement in the water quality that's coming into the bay."
Once Boynton measures the oxygen and nutrients in these sediments, the information goes into computer models that EPA can use to figure out where it needs to spend its new cleanup money, and where to crack down on polluters.
Like most scientists who've studied the bay, Boynton says progress has been frustratingly slow. But he's optimistic about a new start.
"I still maintain that if we start seeing big, big changes in nutrient loads we will see positive changes in the bay very quickly," he predicts, "and by very quickly I mean a year or two."
Making that happen, he adds, is up to politicians and the people who vote for them.