How seaweed is a powerful, yet surprising, climate solution

Picture a place at the centre of a global seaweed revolution. I’ll bet the small English seaside town of Paignton in south Devon is not what comes to mind. A decade ago, I moved from the edge of Dartmoor to the coast. It was about a simple change in work-life balance, but what followed was more surprising.

The kids were four and seven. I’d always tried to inspire them with my scientific research. Moving to Paignton and walking along Broadsands beach one day, I started noticing piles of seaweed.

I’d spent my entire professional career researching microalgae (microscopic marine plants) but knew next-to-nothing about their bigger macroalgal cousins, the seaweeds. This felt like an opportunity to have some fun and for all of us to learn together.

So I bought us a seaweed guidebook, some stickers and set the Allen family the task of finding ten different seaweeds on our local beach. We’d mark a page with a sticker when we found it – the ultimate scientific reward chart. A few weeks later, we’d found 30 and exhausted our sticker sheet.

I was amazed at the diversity that I had never previously noticed. The colours, the textures, the structures – it was like I’d never really seen seaweed properly before. The professional scientist in me kicked in.

My kids and I started taking samples home. I built the kids a lab in a lean-to on the back of the house. We dried them out and put them in little jam jars, akin to a seaweed spice rack. It got me thinking of useful or sustainable things I could do with them.

One day, I posted a picture of these jars on Twitter, with the hashtag #SeaweedApothecary. It started something I could never have predicted.

Seaweed has an astonishing number of uses. It can be used to produce biofuels and fertilisers, foods such as laverbread, nori sheets for sushi and crisps, cosmetics and toothpaste, pharmaceuticals and food supplements like omega-3. I’d also been incorporating seaweed in my day-to-day research at the University of Exeter, trying to convert it into a biofuel.

Then, my colleagues in the broader academic and industrial science community started asking for samples. Like me, they’d been ignoring seaweed too – until they saw my social media posts and realised the potential.

The kids (now both teenagers) are acknowledged on at least a dozen scientific research articles and have continued to help me unlock the potential of seaweed. We’ve done degradation experiments in the raised beds in our garden, tested different seaweeds as feeds for a friend’s chickens, trialled them as fertilisers for our tomatoes – even mixed dried seaweed powder in with cement, to see if it can be used as a structural material filler. All fun, simple science that anyone can do at home.

Local science, global stories.

This article is part of a series, Secrets of the Sea, exploring how marine scientists are developing climate solutions.

In collaboration with the BBC, Anna Turns travels around the West Country coastline to meet ocean experts making exciting discoveries beneath the waves.

Swamped by sargassum

Then came a call from a Mexican friend, asking me to take a look at a seaweed problem. Every year, Caribbean islands and Mexican coasts are inundated with 30-40 million tonnes of floating sargassum seaweed washing ashore.

Rotting sargassum causes ecological and economical devastation, destroying livelihoods and the environment. I started converting it into fuels and fertilisers, trying to turn a massive problem into a positive opportunity. Ten years on, I’d become a seaweed expert.

I was asked to do a podcast on the subject. The presenter, Paddy Estridge, and I chatted about seaweed’s problems, opportunities and potential – and by the end of it, we were both pretty inspired. Together, we founded a company called SeaGen to harness the power of seaweed using autonomous robotics that can seed, cultivate, monitor and harvest it.

Seaweed holds huge potential to create a more sustainable future. But at the moment, this industry lacks the ability to safely seed, grow, monitor, harvest and process seaweed at scale. Solving these challenges is what SeaGen is all about. We’re designing a suite of automated robotic solutions to make abundant, sustainable supply an economic reality.

Our mission is a long way from those initial experiments with the kids, but the joy and pursuit of knowledge remains the same. The sticker chart perhaps holds less appeal to teenagers, but we’ve nearly hit 70 different species and I’m always on the look out for the next.

Those initial seaweed samples paved the way for a whole new aspect to my research portfolio, led to millions of pounds in grant funding, and the creation of a company employing a dozen people. Now, I’m part of a global seaweed and robotics revolution.

Not a bad outcome from a walk along the beach.

Listen to episode two of Secrets of the Sea here on BBC Sounds, presented by Anna Turns for The Conversation.

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