Ceramic disks with eelgrass plants woven into them sink to the bottom of the water column, so they don’t have to be planted at low tide. In the ocean, the disks settle into the sediment. PHOTO BY EARL BRECHLIN

Pottery kiln aids in eelgrass restoration

BAR HARBOR — A multi-year eelgrass restoration project at the Mount Desert Island Biological Laboratory (MDIBL) got a boost this summer with the development of a new technique that will make transplanting the grasses easier.

Jane Disney, director of MDIBL’s Community Environmental Health Lab, has been directing the project to bring back ecologically important eelgrass beds in Frenchman Bay since 2007. The submerged grass provides habitat for several marine species, including commercially important ones. They also prevent erosion and improve water quality.

“We’ve continued to refine our method,” she said. In 2013, MDIBL scientist George Kidder and others published a scientific paper on eelgrass restoration using biodegradable grids in the “Journal of Coastal Research.”

Jane Disney and one of the new restoration disks that she hopes will allow eelgrass restoration projects around the state to scale up. PHOTO BY EARL BRECHLIN

Jane Disney and one of the new restoration disks that she hopes will allow eelgrass restoration projects around the state to scale up.

“At first, we were using wire grids,” Disney said, “but we had to take them back in by order of the Army Corps of Engineers,” who were concerned about leaving metal on the ocean floor. They switched to wooden frames with biodegradable string, but they were labor-intensive to set up and had to be set on the bottom at low tide.

“We usually get a couple of good low tides a summer,” she said, and the whole process had to happen all at once because the frames were too large to store in a fish tank.

“We brainstormed last year with kids and parents in our Young Environmental Leaders program,” Disney said. “We were recognizing that the more of those you try to do, the harder it is. I had heard that up in Canada they were using metal washers for similar projects, something you can just drop in the water and it will sink to the bottom, but I didn’t want to go back to putting a lot of metal at the bottom of the ocean. We wondered if you could make a washer out of something biodegradable, or at least inert.”

One of the parents in the group, Mary McInnes, is a professor of art history at Alfred University in western New York. McInnes spoke with fellow professor William Carty, a ceramic engineer, about the conundrum. A few months later, “they came back with this beautiful ceramic disc with five holes,” Disney said. The disks are molded of soft clay and fired in a pottery kiln. If necessary, they easily can be mass produced.

Carty’s group at the university sent 70 of these six-inch “restoration disks” for trial use by Disney’s lab this summer. “We weave plants in and out of the holes,” Disney said. “The real beauty is I can get volunteers and students to weave these disks whenever it’s convenient and hold them in tanks if we need to.”

They’re not reliant on the tides for the project.

“We’ll see if we can get an eelgrass bed established out of these 70. Already the disks are settling into the sediment,” she said.

The eelgrass restoration project may wind down in Frenchman Bay, Disney said, because the grass seems to be recovering in the area. There aren’t as many green crabs. Green crabs eating the eel grass was thought to be one of the reasons for the disappearance of the plant in many places two years ago.

The MDIBL group is now consulting with groups working in Deer Isle, Stonington, Casco Bay and the Bagaduce River on similar projects.

Liz Graves

Liz Graves

Reporter at Mount Desert Islander
Former Islander reporter and editor Liz Graves grew up in California and came to Maine as a schooner sailor.

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