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#FantasticFibres: Seaweed Fibre Catches Carbon and Looks Great

December 20, 2019
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Seaweed: you’ve seen it at the beach, but prepare to see it in stores. Already a common additive in beauty and health products and ready to make a splash in the world of ecofashion. There are currently 2 main producers of it, SeaCell and AlgiKnit, and they are out there winning awards and attracting big name brands like lululemon and Frank and Oak. So far, it’s mostly been used for knits, underwear, and athleticwear, but seaweed fibre’s carbon-capturing potential means it might explode in popularity very soon. 

Kelp’s Environmental Benefits

So it turns out seaweed has been quite the climate-positive heavy hitter this entire time. Research is increasingly pointing out how coastal kelp forests growing worldwide are some of our best assets in the fight against climate change. Impressively, they can grow up to two feet per day, can sequester 20 times the carbon of terrestrial forest, and also work in tandem with mangroves in protecting coastline communities from storms. Once the plants die, some of them sink to the bottom of the ocean to decompose, hiding away that carbon instead of releasing it into the atmosphere. And since they are underwater, kelp forests avoid the pesky wildfire issues we have on land. Their presence on coastlines means that seaweed forests absorb a lot of sewer and agricultural run-off and use it to further growth. Kelp forests also provide shelter and habitats for a huge variety of marine species like fish and otters much like coral reefs do.

Many of these benefits are transferable to fashion. Seaweed grows everywhere at rapid rates, and eats carbon like little else. Realizing this, a couple of enterprising firms have decided to farm it to produce cloth. SeaCell is currently the biggest, using a species called Knotted Wrack found in Icelandic fjords and northern waters to create knits and athleticwear. SeaCell says they sustainably grow and harvest their kelp to encourage faster regrowth, contributing to that carbon-sucking kelpy goodness. They also use the same manufacturing process as lyocell to ensure a closed-loop process and no chemical waste or runoff. SeaCell is also OEKO-TEX Standard 100 certified, vegan, and biodegradable. 

Seaweed in Practice

The trick with SeaCell is that the kelp is actually an additive blended with cellulose, which is wood-based. This makes it a versatile option, but also means that the true percentage of seaweed present in the fibre is unclear and possibly quite low. That said, this might make it an easier eco-fibre to add to a collection. Proof of this is visible in big brands like Frank and Oak and lululemon creating pieces with it.


AlgiKnit, on the other hand, is committed to engineering fully seaweed-based fibres. Their seaweed of choice is oarweed, famous for growing worldwide and at a rate 10x faster than bamboo. It is ultra-renewable, and farming it provides fast and easy income for various coastal communities. With oarweed, AlgiKnit uses a closed loop production cycle to create a ‘bio yarn’ polymer that they are testing for knits and sportswear. It’s supposed to be largely chemical free and fully biodegradable, but only when the wearer is ready. Then, back to AlgiKnit it goes to be broken down by specific microorganisms and used to feed the next round of kelp.

This cutting-edge idea has attracted some big supporters. AlgiKnit is a graduate of the 2018 RebelBio startup incubator, and has won grants from National Geographic, the Fashion Institute of Technology, and the American Association of Textile Chemists and Colorists, to name a few. And it’s showing promise – they have successfully created their yarn, and even designed an in-house performance shoe.

Where it Stands Now

By encouraging farming of kelp, these two firms are encouraging growth of one of our best all-natural carbon-sucking methods. Seaweed fibre is a versatile, biodegradable option that has the potential to do double-duty and help with our carbon problem. That said, like with all of our #FantasticFibres, concrete lifecycle analysis data is nonexistent. SeaCell is commercially available, but as a blend with cellulose, not entirely on its own, and AlgiKnit is still in experimentation stages. And the kicker is that despite kelp being one of our best defenses against the looming threat of climate change, increase in ocean temperatures is likely to wipe them out. This means supply might become harder in coming years. 

All hope is not lost yet! If you are looking for an alternative to common, less sustainable knit fibres, seaweed is a promising option.