But the uprooted plants live on, some of them helping clean up Boston Harbor and others participating in a scientific experiment that could help spread the species to other waters. And many could eventually find their way back to Gloucester Harbor once the storm drain work is done.

Eelgrass is a flowering marine plant that grows in sand and mud. Eelgrass beds are an important habitat and nursery for fish, shellfish and waterfowl.

The plants were harvested in two stages. In August, the Massachusetts Division of Marine Fisheries organized an effort that collected 6,000 eelgrass stocks, which were then transported and replanted in Boston Harbor in a restoration effort.

Another 7,000 plants were harvested this week by divers and about 80 volunteers recruited through the Massachusetts Institute of Technology's Sea Grant program and the state Coastal Zone Management agency.

"It's been amazing how many people have been involved," said Kathryn Glenn, CZM's regional manager for the North Shore.

The eelgrass pulled up this week is being stored at the Gloucester Maritime Heritage Center on Harbor Loop and at tanks at four schools.

Through Sea Grant, The Maritime Heritage Center, with MIT and CZM, established a 2,000-gallon tank that will be a storage bed for about 3,000 of the plants collected.

The other half of the plants will be stored in a "geocoir," a floating raft, that will be located at one of the piers near the Maritime Heritage Center at Harbor Loop. Constructed from coconut fibers, the raft will house the plants underwater throughout the winter and will be the first raft ever tested in New England to store eelgrass for long periods of time.

"The tank method has been tested and found successful in Washington State, but no one has ever tried storing eelgrass on a raft for a long period of time," said Brandi Wilbur, MIT Sea Grant educator.

Wilbur said the eelgrass will be weaved into 1 meter square fiber purses that will then be attached to the raft. Each of the 17 purses will hold 200 stocks of eelgrass.

The long, grasslike water plants help maintain good water quality and stabilize shorelines against erosion while providing a haven for fish, crabs and other ocean creatures, Wilbur said.

The overall idea of the Sea Grant educational and outreach program is to test whether eelgrass can be stored and raised either in storage tanks or on the geocoir, said Tay Evans, a marine biologist with the Division of Marine Fisheries. Evans added that the geocoir will be a great way to test the different growing habits of the plants and whether the sea plant would learn to adapt to the new environment of the raft.

The eelgrass will also be tested in smaller tank environments by science students at Winthrop Elementary School in Winthrop, Minuteman Regional High School in Lexington, Essex Agricultural & Technical High School in Hathorne and Dana Hall School in Wellesley. Each school will work with a tank of seedlings and a tank of adult eelgrass stocks.

"This has been a great opportunity for the students," said Chris Whitaker, an Environmental Technology teacher at Minuteman High School. "We have done a lot of work with raising and testing fish and turtles. This is our first opportunity to study a sea plant. Hopefully if this succeeds, we can invest in more tank space and a bigger project next year."

It was a busy day for more than 80 volunteers who spent Monday hard at work collecting and weaving plants, but Tony Wilbur, CZM marine biologist and organizer of this final harvest, said the work has just begun.

"There will be a lot of work that goes into maintaining this project," Wilbur said. "I am concerned that there will be 'fouling organisms' - organisms that will attach to the plant and smother it. We really don't know what will happen. But the goal is to learn as much about the eelgrass and its habitat as possible."

While both the tank and raft displays at the Heritage Center will remain for public exhibition, at the completion of the Washington Street Drain and Outfall Project next fall, the city will be required to replant the eelgrass bed that was disturbed by construction and plans to do so with the harvested plants stored in local waters.

Talking eelgrass

What: Eelgrass, a flowering marine plant that grows in sand and mud and is an important habitat and nursery for fish, shellfish and waterfowl.

Taken from: Waters off Pavilion Beach

Taken to: Boston Harbor and holding raft and tank at Gloucester Maritime Heritage Center

How many: About 13,000

Why: To make way for construction of a 550-foot storm drain outfall set to begin in mid October.