The possibilities of seawilding and the future of carbon capture

This article is part of our collaboration with The Ferret. Each edition will see a different issue in Scotland tackled, and this time we're looking at seawilding and the potential future of carbon capture​. Sign up for the free monthly newsletter HERE.

‘WATCH out for orange crabs, and jellyfish … they can give a sore sting,” warns Philip Price. “Pour hot water on it as quickly as you can.” It’s just after 9am on a dreich day in August and he’s in a boatshed on the shore of Loch Craignish, in Argyll.

Price – who describes himself as a “seawilder” – is giving a safety talk to a team of volunteers about to snorkel in the loch and harvest seagrass underwater. “Use this barrier cream for protection,” he adds, referring to the perils of jellyfish while holding up a plastic bottle. ”Put it on your face, hands and lips.”

The six volunteers – who hail from as far afield as Cambridge, London and Sardinia – listen intently and all heed Price’s advice. They have donned wetsuits and after the protective cream is applied, face masks and flippers are adjusted as the team prepares for the cold water plunge. The temperature of the loch, Price says, will be less than 15 degrees but he stresses that no-one is expected to stay in the water if they get too cold.

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For four years now, Loch Craignish – which lies between Oban and the Crinan Canal, and opens to the Isle of Jura Sound – has been home to a seagrass meadow restoration project hailed as a pioneering way to help mitigate the climate crisis.

Seagrass meadows are naturally occurring ecosystems of flowering plants in shallow waters. They are an essential species which retain carbon while providing a habitat and spawning ground for fish and other marine life. The meadows have been dubbed “the lungs of the ocean” and some are capable of absorbing carbon dioxide 35 times faster than tropical rainforests.​ They also improve water quality, reduce contamination in seafood, and offer protection from flooding and storms.

Seagrass meadows have been declining globally since the 1930s, however, with ​estimates that seven per cent are being lost each year. The UK’s meadows have shrunk by up to 92%, with roughly half this loss occurring in the past 90 years.

Pollution from agricultural runoff and destructive coastal development are to blame, as well as destructive fishing and dredging which damages seagrass meadows directly. Extreme weather, rising temperatures and the acidification of the ocean, caused by carbon dioxide emissions, also endanger these habitats.

Now, in the fight against climate change, restoring seagrass is viewed as increasingly important for carbon storage globally. Seagrass is part of a UN project called Decade On Ecosystem Restoration while £2m has been allocated to restore meadows in Scottish waters​. This initiative​ – a public/private ​project – will see at least 14 hectares of seagrass planted over the next few years, to add to projects already under way – including Loch Craignish, where Price and colleagues at a charity called Seawilding have been at the vanguard of trialling restoration methods.

“Seagrass was just this weed that grew in the sea for a long time then suddenly somebody looked at it and studied it for a bit,” Price tells The Ferret. “Then scientists realised what an incredible species seagrass is – what it does for the ecosystem.”

“It’s probably taken a while for that science to infiltrate into the wider consciousness, and we’ve just hit the point where people say: ‘Wow! Seagrass is incredible, it does this, this, this, and this. Oh no! We haven’t got very much of it left – and we used to have loads’.”

Price says we should think about restoration as like planting woodlands – you start by planting a few small saplings and, after several years, there will hopefully be a large forest.

But what evidence is there that restoring seagrass meadows is viable over the long term for carbon storage? How effective have Scottish trials been so far? What challenges exist, and can Scotland learn from international projects?

A core sampling takes place in Loch Craignish Image (Image: Philip Price/Seawilding)

As part of The Ferret’s solutions journalism project, Fixing Scotland, in collaboration with the Sunday National, we wanted to look in-depth at both its potential and limitations for addressing climate change locally and improving our waters.

Due to climate change, Scottish winters were nine per cent wetter between 2010 and 2019 than they were between 1961 and 1990. With winters getting warmer, there is projected to be less snowfall in future, and summers are expected to become drier as well as hotter in future.

Scotland aims to reach net-zero by 2045 and carbon storage is a vital part of the plan.

Loch Craignish has been an experimental site since 2021 when Seawilding was formed – the UK’s first community-led native oyster and seagrass restoration project. It aims to restore lost biodiversity, sequester carbon, create green jobs and mentor other community groups to do the same. So far, 350,000 native oysters have been restored to Loch Craignish and 300,000 seagrass seeds have been planted, and Price and colleagues are trying to work out the best way to restore seagrass at the lowest possible cost, and at scale.

Seawilding’s research has helped inform what it calls the “infant science of seagrass restoration” and its results have been shared with other projects worldwide, community groups in Scotland, as well as the Scottish Government. Loch Craignish currently has ten small seagrass meadows totalling approximately five hectares, but surveys suggest there are around 80 hectares of seabed ripe for restoration.

It’s labour-intensive work and volunteers are welcomed by Seawilding to help. Depending on the tide today, we will be in the water harvesting seeds for around 30 minutes to an hour, chaperoned by Price and other Seawilding staff.

The seeds are harvested underwater by hand, with seed pods carefully snapped off and bagged. They are stored, processed and later planted underwater. Like plants on land, seagrass starts growing in the spring, producing its seed in the summer.

After watching a short film on seagrass harvesting, we navigate a slippery, stony shore to the lochside, ready to start snorkelling and gathering seeds. Masks are donned and heads are lowered into the water to practice breathing, and the group sets off. It’s a pleasant, meditative experience and any jellyfish that appear are easily swerved. No-one gets stung.

Challenges

SEAWILDING has made considerable progress since 2021 but there are challenges. Price stresses there needs to be a long-term commitment to seagrass restoration – instant success isn’t feasible. The charity’s germination success rate is between five and 10%. That means from 100,000 seeds planted only 5000 to 10,000 turn into plants. This rate is much higher than what occurs naturally though.

“The actual germination rate of seeds in the wild is usually down at 0.1 per cent,” Price explains. “But before humans destroyed a lot of the seagrass, there would have been vast meadows with billions of seeds, so 0.1 per cent would be possibly another million plants in a meadow, so it worked really well at that level.”

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“With small transplantations we need it to be a lot better than that,” he adds. “All our efforts are channelled into how you get seagrass meadows to expand. “We’re trying all the different methodologies so we can say this is the one that is maybe going to work.”

Solutions

IT’S a learning curve, a case of trial and error. One of today’s volunteers is Jenny Black, a marine consultant with an organisation based in Oban called SAMS-Enterprise. She’s involved in mapping coastal areas to try and work out the best places for seagrass restoration.

“We’re helping Seawilding with some of the monitoring and analysis of soil,” Black says. “One thing which [Seawilding is] finding is that the microbiome of seagrass meadows is extremely important”. The microbiome is made up of “microscopic organisms in the soil, potentially key to the success of a restoration project because this helps the environment to grow,” she explains. “The soil health is very very important for restoration.”

Black points out that seagrass species in Scotland are not as good at storing carbon as some others. “The Mediterranean species posidonia oceanica often skews the statistics around seagrass carbon storage potential, which includes some of the statistics that we see in news headlines, like how seagrass can store 10 times the amount of carbon as a terrestrial forest can. This isn’t to say that the species we have around the UK – zostera marina and nanozostera noltei – don’t store carbon, they just don’t store as much as this species.”

In terms of the health of our ecosystems, seagrass is extremely important, Black adds, as it creates habitat and ensures we have clean water. “I think that’s something that is sometimes overlooked when there’s a conversation about climate change,” she says. “It’s very important to have a diverse coastline because it offers so many other benefits, as well as carbon storage.”

Seeds from one place can be moved to another location to aid restoration, Black points out. One example is a project in the Firth of Forth called Restoration Forth, launched in 2022, which is trying to regenerate seagrass meadows with 25,000 seeds harvested in Orkney.

The meadows in Orkney and the Firth of Forth are genetically similar, researchers found, in contrast to seagrass from the west coast, which are quite different.

A sunny autumn view of Loch Craignish in the Scottish Highlands (Image: Peter Watson/Loop Images/Universal Images Group via Getty Images)

Lyle Boyle, a seagrass officer with The Ecology Centre, is working on the multi-partner project. He says the Orkney seeds have produced encouraging results at two sites where there are existing seagrass meadows, Drumsands and Burntisland. “We’ve done a lot of investigating and trials but large-scale restoration hasn’t been pursued yet,” says Boyle.

Germination rates were good at Drum Sands (10 to 12%) and Burntisland (five to six per cent) but for another seagrass bed, at Belhaven Bay, were “inconclusive”. “It looks really promising but we had easterly storms last year which undid a lot of our good work on the seabed,” adds Boyle.

Solutions

ADVERSE weather is just one challenge in Scotland. Another hurdle is how to scale up seagrass restoration and reduce costs because harvesting seeds and transplanting them by hand is a time-consuming process. In Edinburgh, Niall McGrath has a plan.

He is the co-founder and CEO of green-tech firm, Robocean, and his aim is to build a subsea robot to place seagrass seeds on the seabed, faster and cheaper than currently available methods – a method he describes as a “minimum viable product for commercial markets” globally.

McGrath, who studied mechanical engineering and renewable energy at the University of Edinburgh, says it can take 2000 volunteers six months to plant just one hectare of seagrass – the equivalent of 1.5 football pitches – at a cost of between £200,000 and £500,000.

“If we can have an autonomous system that can deliver multi-hectares of seagrass restoration in a single day then we can bring those costs down,” he says. “Also, the restoration process is slow to start up and you need a lot of resources. It’s very volunteer-driven in the UK and on the east coast of America, and the Mediterranean – that’s quite a common approach.

“You need a large workforce to make it viable. Volunteers bring your costs down. You’ve got to have the resources to collect seeds at scale and store them, process them and plant them afterwards, which is a massive process. We want to deliver restoration for anyone, using the same processes anywhere in the world, and make it affordable and scaleable.”

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In June, McGrath attended an international seagrass conference in Naples, Italy. It was three times the size of previous events, he says, indicative of the increased global interest in seagrass restoration.

Elsewhere, seagrass meadows have been planted at scale. In the US, researchers from the University of Virginia planted seeds from Chesapeake Bay into smaller bays. Some 72 million seeds were used and nearly 10,000 acres of seagrass now sway underwater. With the seagrass restored, the marine ecosystem has flourished with anchovies, silversides, pinfish, and blue crabs all returning.

In Scotland, there is now £2m of funding available to restore Scottish seagrass meadows. The project, announced in March by NatureScot, is a partnership between the Scottish Marine Environmental Enhancement Fund and Scottish and Southern Electricity Networks Distribution. According to NatureScot, this “is the largest-ever single donation to marine enhancement in Scotland” and the fund will be open for applications later this year.

The wildlife agency’s chief executive Francesca Osowska described it as a “unique project” and said: “Nature and climate are intrinsically linked; if one is suffering, the other will be as well. So we need to take care of our seas and our seagrass.”

Price cautions that funders shouldn’t expect instant success. He says restoration is a “difficult sell to a funder” as the pitch is “we’re probably going to fail for a couple of years but then we’ll succeed”.

He adds: “If you look at any restoration project globally there are 10 years of things not quite working before it takes off and that’s one of the challenges we have as a charity. We’re talking five to 10-year timescales. You want to see success. But unfortunately for ecosystems, success takes a bit of a punt. We just need to have more time to see how these successes roll and scale up – and that’s a long-term process.”

But Price is optimistic. He says Seawilding is doing a “really interesting experiment this year” by using plants from an existing meadow and transplanting some to its edges to make the meadow expand outwards. This worked “very well in Canada” he says. They are also trying different sediment types to see if that affects the viability of this technique. “So that’s been fantastic and it looks amazing at the moment. We just finished our trial and did about 10,000 plants. And it looks incredible so fingers crossed it survives the winter.”