Thursday, October 15, 2009

Biologists Fight Erosion in Jamaica Bay by John Lauinger - NY Daily News

Read original...

Biologist Melissa Alvarez examines clumps of salt marsh grasses on Elder’s Point East in Jamaica Bay. Showalter - News

This is the new hope for the bay's future.

The island's picturesque shores are covered in clam shells and frequented by sea gulls, but its current form is almost entirely man-made - just like the capped landfill towering above the bay's northern shore.

Three winters ago, at a cost of roughly $15 million, the U.S. Army Corps of Engineers molded a mountain of sand around the scattered remnants of the erosion-ravaged island, and rooted a million salt marsh grasses by hand.

Still maturing, the 38-acre wetland has served as a laboratory of sorts where scientists have learned lessons that will be used in the reconstruction of a neighboring island, Elder's Point West, beginning next month.

"There were a lot of experiments that were tried here that will make Elder's West even better," Len Houston, chief of the corps' environmental analysis branch in New York, said during a recent tour of Elder's East.

East and West were once part of a single 130-acre island that decayed into smaller pieces due to the wetland-dieoff phenomenon that some scientists predict could one day eradicate the bays' tidal marshes.

Contracts were awarded Sept. 29 for the Elder's West project, which has a $12 million price tag and will encompass 30 acres to 40 acres, depending on the final design, Houston said.

By all accounts, the grasses are thriving at Elder's East, and erosion has been minimal.

"We're not losing sand - even where there is erosion, it is shifting onto the island, not off of it," said Melissa Alvarez, a biologist with the corps.

More than 85% of the transplanted grasses - grown from seeds taken from the island's original stock - survived.

"The site is very well vegetated," said Chris Miller, a plant materials specialist for the U.S. Department of Agriculture, which raised the seedlings. "The plants are doing very well."

Based on lessons from East, the reconstruction of West will include more widespread use of fertilizer and a greater reliance on planting grass seeds, as opposed to seedlings, which will make the work less expensive.

Some scientists believe the bay's wetlands - now less than 1,000 acres - are vanishing at a documented rate of 40 acres per year because accumulated toxins in the marshes are causing their soil bases to break apart and wash away.

At East, sand was filled in around existing fragmented clumps of grass, and seedlings were then transplanted into the new sand. But the existing soil base, which has a soot-colored, gooey appearance, proved inhospitable.

"Now, most of the original clumps are gone and none of those seedlings survived," Alvarez said, noting that existing clumps at West will be transplanted into new sand.

"The substrate that is there is pretty much toxic to the plants," Alvarez said. "Once you pull the plants out of the old clumps, they do fine."

Elder's East alone has not reversed the alarming die-off trend, experts said, but it has become an important cog in the bay's ecosystem, providing habitat for horseshoe crabs, soft-shell clams and blue mussels.

"You never saw soft-shell clams here before," Alvarez said. "Blue mussels right now are not very common in this bay, so that is very encouraging."