Capturing carbon 35 times faster than the Amazon, seagrasses have faced centuries of decline. Now restoration projects across North America are seeing their meadows quadruple in size.

Credit: Nicolas Winkler Photography.

October 9, 2025

This story is part of:

Waterline

Waterline is an ongoing series that explores the solutions making rivers, waterways and ocean food chains healthier. It is funded by a grant from the Walton Family Foundation.

This story has been co-published by Reasons to be Cheerful and the Outrider Foundation.

In late spring last year, Betty Hodgson, president of the Nova Scotia non-profit group Friends of the Pugwash Estuary, sat in the bow of a small boat with Kristina Boerder, a marine biologist at Dalhousie University. As they maneuvered the dingy through the shallow estuarine waters that flow undaunted into Canada’s Northumberland Strait, the pair leaned over the boat’s edge, scanning below the rippling surface for any sign of silvery-green ribboned blades of eelgrass. What they were really looking for was hope.

Living in shallow water along the intertidal coastlines and estuaries of more than 190 countries, eelgrass, or Zostera* marina*, is part of the seagrass family of plants and the most common seagrass species in Canada.

Despite covering just 0.2 percent of the sea floor, seagrasses account for an estimated 10 percent of all the carbon stored by the world’s oceans. They are also able to capture carbon from the atmosphere up to 35 times faster than tropical rainforests such as the Amazon.

Globally, however, seagrasses have declined almost 30 percent since the late 1800s. At current rates, it’s estimated that a football field’s worth of seagrasses disappears every second.

Scientists don’t yet know all the reasons for the plant family’s decline, but they do know some of the major stressors, not least climate change and its associated impacts such as warming sea waters, ocean acidification and increasingly intense storm surges. Boerder, lead scientist with Dalhousie University’sCommunity Eelgrass Restoration Initiative (CERI), points to Hurricanes Fiona in 2022 and Dorian in 2019 that swept along the coastline of Nova Scotia and uprooted entire eelgrass meadows.

There are other factors at play too, including seagrass wasting disease, which wiped out up to 60 percent of eelgrass in the Pacific Northwest between 2013 and 2015, and the invasive European green crab, which uproots meadows while burrowing and feeding.

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These pressures are compounded by human activities such as coastal development, overfishing and pollution. The result is that this once thriving climate hero is up against the ropes.

It’s something Hodgson knows well. “Local people will call me,” she says, “and say, ‘I always cut eelgrass for my garden, and there’s no eelgrass anymore!”

But Hodgson also recalls the moment that the fate of eelgrass in the Pugwash Estuary changed for the better. Looking over the side of the dingy that spring day, she spotted one plant. It was all the proof she and Boerder needed to know eelgrass was still able to grow in these waters.

Following that sighting, CERI and Friends of the Pugwash Estuary spearheaded an eelgrass restoration project in the summer of 2024 that saw eelgrass shoots from the River Philip (which runs parallel to the Pugwash River) transplanted into the sediment of the Pugwash Estuary.

It was a gamble. The River Philip is a freshwater channel right up until it meets the Northumberland Strait. By contrast, Hodgeson points out, the Pugwash Estuary is a brackish mix where the cold saltwater of the Northumberland Strait presses inland to meet the river’s fresh current.

It may seem a small thing, but transplanting eelgrass from one environment into another with even a small change like this could spell disaster for restoration efforts. With the adage “nothing ventured, nothing gained” guiding them, volunteers from Friends of the Pugwash Estuary pressed forward, working with CERI to repopulate the estuary.

Eelgrass replanting at the Pugwash Estuary. Credit: CERI.

“We had an eelgrass planting party,” Hodgson says, “and invited people from the community to come out and get wet and muddy, which they did and had a ball.” The newly restored meadow took off and, a year later, according to Hodgson, it was 300 to 400 percent larger in area than when it was first planted.

Restoring eelgrass meadows and outsmarting some of the stressors causing its decline is also top of mind on the opposite side of the continent, on Washington State’s San Juan Island. Here, the story is strikingly similar to Pugwash Estuary. “There are locations such as Wescott Bay and False Bay on the island that apparently used to be full of eelgrass,” says Mitch McCloskey, eelgrass conservation manager for the San Juan Islands Conservation District.

This past spring, McCloskey and his team began planting small patches of eelgrass along the coastline of the island to see if it would grow. It’s too soon to tell if the trial has been successful, and if the eelgrass can survive a full year, but this isn’t dissuading McCloskey, who is already looking at new ways to implant more eelgrass seedlings into the seabed.

“Things we do when we’re planting that gives the grass a little extra edge are to push the seed down in the sediment with injection seeding guns,” McCloskey says. “But now we’re going to actually glue seeds to cockle shells.” The idea behind bivalve-facilitated seeding, as this process is known, is that as the cockles burrow, they help plant the seeds in the sediment and aerate the soil. This stirs up essential nutrients that help the seeds’ survival. In the future, McCloskey hopes this method will help replenish the lost meadows of the San Juans.

While these efforts and those in the Pugwash Estuary are fairly new endeavors, a seagrass restoration project in Virginia has been ongoing for more than two decades. To help scientists restore meadows, volunteers working with the Virginia Institute of Marine Science and the Nature Conservancy collect eelgrass shoots along the Virginia coastline each spring. The shoots are then cured in climate-controlled tanks before the seeds are extracted and sown back into the wild.

This is a stark improvement following the decimation of the seagrass meadows in Virginia’s coastal bays in the 1930s.

It’s the ability of restoration projects such as those in Virginia and Nova Scotia to find a balance between community and science that Broeder finds so rewarding. To her, the work is so much more than just restoring and studying eelgrass, it’s a way to help heal the environmental grief she feels many people are experiencing in the face of the constant bombardment of negative news about the environment and climate change.

“Scientifically speaking, we could do this restoration work more efficiently and quicker ourselves,” she says. “It’s seeing how people change their attitude and awareness. The stewardship people feel towards one ecosystem snowballs to other ecosystems.”

Scrolling photos courtesy of Nicolas Winkler Photography.