Aquatic grasses bounce back

Chesapeake: Anti-pollution measures in Pennsylvania contribute to flourishing vegetation that supports bay crabs and fish.

August 25, 2004|By Rona Kobell | Rona Kobell,SUN STAFF

HAVRE DE GRACE - Mike Naylor planted his boat in the grass-filled waters near the shoreline, pulled on his snorkel mask and offered a salesman's promise about the vegetation below.

"I'll be back in five minutes or less," he called, "with 10 species or more."

The Department of Natural Resources biologist was even faster than he predicted. Within three minutes, he waded back to the boat with a fistful of wild celery, coontail and yellow-flowered water star grass.

"In all my travels of the bay, I've never seen such a huge geographic area where practically all the shallow water habitats are covered in aquatic plants," Naylor said. "It's just remarkable."

At a time when research shows that grasses throughout the bay have reached a 20-year low, the Upper Chesapeake Bay is experiencing diverse grass growth at a pace not seen in decades. The lush beds are not only beckoning more fish, crabs and clams, but also waterfowl that depend on the grasses for food.

That the comeback is happening in the shallow waters known as the Susquehanna Flats is even more surprising, researchers say, both because the area is so vast and because its rebirth is largely driven by what is happening in Pennsylvania.

Historically, the Keystone State's vast farming operations and its sewage treatment plants have been responsible for a fair amount of nitrogen and phosphorus in the Susquehanna River, which delivers that pollution to the bay.

The nutrients encourage the growth of algae, which block sunlight so the grasses can't grow. Without grasses, crab, fish and waterfowl populations drop significantly.

Bay restoration officials who have often focused their criticisms northward are now pointing out that Pennsylvania is making progress. According to the Chesapeake Bay Program, the multi-agency initiative overseeing the bay cleanup, the amount of phosphorus in the upper bay has declined in recent years, and it gives much of the credit to Pennsylvania.

"What that does say is that the work they've done so far is obviously making a difference in their local streams," said Richard Batiuk, the bay program's associate director for science.

John Murtha, the Pennsylvania Department of Environmental Protection's wastewater operations and compliance chief, said phosphorus reduction efforts that the state began in the 1980s are showing results now. He also said that continued limits for sewage treatment plants on phosphorus discharges are finally having an effect.

"You do not get rid of phosphorus" once it's in the watershed, Murtha said. "It can't be converted to something else. If you put it into the system, it remains there until it's flushed out."

Bay advocates say Pennsylvania's land preservation and forest conservation programs are also contributing to water quality. And state officials say the clarity should improve even more in the Susquehanna under new farm management regulations.

But Pennsylvania's efforts aren't the whole story. The Susquehanna Flats, so named because of their flat and shallow bottom, are covered with another shade of green that scientists think might be working in tandem with the nutrient reductions to help the grasses along.

Ironically, the helper plant is a type of algae, a dark green scum that is covering acres of the flats like a shag carpet. It's so dense in places that it traps clams. More than once, the plant trapped Naylor's propeller, stranding the boat on a canopy of Astroturf.

Though the algae has been nothing but trouble for crabbers, researchers are looking into evidence that this unusual species is actually helping the grasses grow by trapping sediment.

"It's hard for people to see that this could be the ugly side of restoration," said Peter Tango, chief of quantitative ecological assessment for the Maryland Department of Natural Resources.

The algae bloom would not be the first strange water clarity tool surfacing in the bay this summer. Near Anne Arundel County, several rivers are filled with a small mussel that seems to be filtering the water. But researchers say that, in order for the grasses to be this abundant, there also has to be some nutrient reduction going on.

Whatever the reason, the return of the grasses has brought hope that Havre de Grace's signature bird, the canvasback duck, might soon follow.

The red-headed ducks, which fed off the wild celery grasses, were once so abundant that the sky would be dark as they flew across the bay en masse. Canvasbacks covered the Susquehanna Flats and were so linked to the wild celery that their species name, valisineria, is derived from the Latin name for the plant.

Canvasbacks began to disappear in the 1970s, after Tropical Storm Agnes ruined much of the wild celery, forcing them to winter elsewhere.

After years in which canvasbacks were rarely seen outside their glass cases at the city's decoy museum, locals are reporting the bird is coming back - if not en masse, at least occasionally.

"They're steadily coming back," said Margaret C. Jones, the decoy museum's special events coordinator. "There are more ducks coming into town than there used to be."

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