The 'secret weapon' in fight against climate change — planting eelgrass

We've all heard of planting trees to combat climate change. Now, a team in Nova Scotia is working on "reforestation" for the ocean. 

Dalhousie University and the Ecology Action Centre in Halifax are managing a project this summer to plant an often overlooked species — eelgrass — in the race to remove carbon dioxide from the atmosphere.

To the untrained eye, eelgrass looks like your average seaweed, but project lead Kristina Boerder says it's much more.

"It's a bit of a treasure, a secret treasure. Not a lot of people know about it," said Boerder.

Eelgrass boosts biodiversity along shorelines by providing shelter for young fish, crustaceans and even food for some waterfowl. It also has many benefits for humans.

"It protects our coasts from erosion. It's good for water quality. And also it stores our emissions. So it's a secret weapon in our fight [against] climate change," she says.

Seagrasses on the whole absorb carbon and methane through photosynthesis and sequester them in their root systems. One study estimates an acre of seagrass can store over 335 kilograms of carbon per year — the equivalent of carbon emitted by a car driving from Yarmouth, N.S. to Dingwall, N.S. eight times.

Researchers are working to see how effective eelgrass is at carbon storage in Nova Scotia specifically. 

Its carbon-storing root system also helps moderate levels of acid in the ocean, which are rising due to climate change and damaging the health of some marine life.

But eelgrass meadows are shrinking, according to researchers due to damage from coastal development, pollution, invasive species and some types of fisheries mooring and anchoring practices.

This loss of seagrass meadows is a global phenomenon. One study estimated the world loses up to two football fields worth of seagrass each hour. Boerder says something needs to be done.

Boerder, along with students from Dalhousie and volunteers from the Ecology Action Centre, have spent the summer with snorkels and wetsuits out in the water, working to regenerate this precious plant.

Amy Irvine is a marine biology masters student involved with the project who endures long, muddy, cold days to plant the eelgrass.

"When you see all the trees around you, you recognize how important they are. But then when you come to the ocean, you don't think about this," she said, holding up a piece of the eelgrass.

The study

The team's days are long. Starting at 7 a.m. and going until 6 in the evening.

They meet at Cherry Hill Beach to harvest eelgrass from a lush bed where they suit up, wade in and fill buckets with the green grass.

"This is actually the easiest part of the day," said Irvine. This area is shallow and warm compared to the area where the eelgrass is transplanted.

The planters swim out, with Boerder following them in a boat. She hands them the grass and they dive down through the cloudy water to plant it.

They are trying different planting methods to see which is most effective.

"We don't know what works best for Nova Scotian Water. So we've got to explore that first," said Boerder.

The experiment consists of four different methods: planting seeds on their own, planting seeds in burlap sacks, planting sods, or the full plant with its roots, and planting shoots. They've planted over 6,000 eelgrass plants using these methods.

When it comes to improving biodiversity, planter Lauren La Porte says she's already seeing some results.

"Every time we're snorkeling, we see little critters swimming along in there, we see crabs and lobsters, and those are super beneficial to our local fisheries. "

Civilian science 

Jordy Thomson, the senior marine coordinator for the Ecology Action Centre, is happy to see volunteers coming out to help plant the eelgrass.

"We want to build up public momentum for an interest in conservation of eelgrass as a really critical coastal species for us here in Nova Scotia."

Thomson says community involvement has been key for the project. People offered up their private land for the group to provide access to ocean beds, and volunteers have been helping collect data on eelgrass by filming from their kayaks.

Many people have also been sending information about eelgrass through the iNaturalist app.

INaturalist is an app that encourages citizen science and the Ecology Action Centre asks people to upload photos of eelgrass beds to the app to help map their distribution and better understand their health throughout the province.

"We really are looking for anybody in Nova Scotia who lives or spends time along the coast to get involved and to send in some photos of eelgrass meadows in their area," Thomson said.

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