As an avid admirer of all things mermaid since the age of six, I found this rather practical even before I realised textiles involved time-consuming tasks such as spinning, weaving and dyeing. Mermaids could devote their time to more interesting pursuits like studying the plant life around them. Not that I found it very fascinating; seaweed was decidedly unexciting and a bit yucky to step on underwater (I never knew if those fronds were hiding sea urchins or not!).

I grudgingly learnt to appreciate algae at university, where I was introduced to the amazing ecosystems they create, such as kelp forests (and discovered they could be eaten). Still, they didn’t hold my interest for long and were relegated to the back of my mind… until a few months ago, when I received an intriguing email from a friend.

She wrote from half an ocean away, from a new job in the Canary Islands; after years in a botanical garden, she’d begun working at the Spanish Bank of Algae (BEA). Like me, she hadn’t given much thought to seaweed in decades, and was fascinated by the projects that were underway at the BEA.

One of these projects was delightfully unexpected: a search for textile dyes among the hitherto uncharted fields of algae biodiversity.

They were on a search for sea colours (which, fittingly, happens to be the name of the project).

If mermaids could read this, they would certainly be shocked, perhaps amused. Seaweed and colours? Right, sure…

After the mermaids got over their initial shock I would then remind them that, although dyestuff extraction from algae is a modern development, it does have ancient historical roots — albeit hidden ones.

Algae has entered into colourful partnerships with certain fungi, and the resulting organisms have been exploited for centuries as dyes. Yes, I’m referring to the lichens, of which many species have been used across the globe. One of the most famous ones in the West was orchil (from the Roccellaceae family, especially genus Roccella), treated with ammonia (ie urine) to obtain violet hues. Cottage industries based on orchil-collection were born along the coasts of Scotland, Scandinavia and the Canary Islands; the lichen was then sold in places like London, where a ton of ‘orchella weed’ could fetch £1000 during the 17^th and 18^th centuries.

However, lichens aren’t algae, and their historic use as dyestuffs doesn’t guarantee that its team members taken separately will yield useful colours.

So, if you want to find dyes in seaweed, where do you start?

To the BEA, the answer was rather obvious. They store nearly 1700 strains of algae from all kinds of Macaronesian aquatic environments (marine, fresh water, hypersaline, etc.). For a biotechnologist this is like holding a thousand unopened lottery tickets – an abundance of opportunities to explore whether any of them may be hiding colourful tricks up their watery sleeves.

And they may be hiding many, given how diverse algae are as a group —or rather, a group of groups, loosely held together by a set of common characteristics: they live in water, produce their own food, and know the tricks of oxygen-producing photosynthesis. Yet the approximately 72, 500 species of organisms in their ranks come in all sizes (from microscopic to extra-large), family affiliations (from bacteria to plants proper) and colours.

The pigments that have so far caught the project team’s attention fall under two main categories: carotenoids (yellow to orange; cousins to the compounds in carrots and autumn leaves), and ficobiliproteins, pigments yielding red and blue dyes that no land plant ever learnt how to produce.

(This shouldn’t be surprising: after all, green plants evolved from a small algal offshoot of the seaweed pool, a group that knew just a handful of the many biochemical recipes found among algae; any seaweedy marvels that weren’t on that recipe list were left behind in the water.)

As scientific director Juan Luis Gómez Pinchetti explained, the BEA was in charge of colour-searching among the tiny: cyanobacteria, and micro-algae. Based on previous studies, 25 candidates were first selected to participate in the Miss Seacolors competition. They had to answer hard questions, such as ‘Can you be grown successfully under certain conditions? How quickly can you do so?’ And, ‘Do you even know the recipe for the molecule we’re after? How much of it do you normally produce? Can you churn out more if we tweak growth conditions?’ And so on and so forth.

Other project partners were in charge of the heftier seaweeds; others had to test the winners’ pigments (extraction, mordant use, dyeing methods), making sure they performed well under standard processes. Being a textile dye is a tough life: you must attach fast and hard to a wide range of fibres and then hold on to them for dear life, else you fade away and leave the wearer deeply disappointed.

I’m sure mermaids were much easier to please than land-dwellers.

The project isn’t aimed at dabbling around with colourful seaweed to be used in small-scale craft workshops; it’s part of a quest to find substitutes for the synthetic colours currently used in the textile industry.

Industry!? A tall order for our watery maids; nevertheless, the results look encouraging. As I write this, I’m looking at pictures of cotton T-shirts with the project’s logo printed in green and pink, and I dream of a future in which the colours on my clothes come from a similarly sustainable source, produced following environment-friendly processes.

We’re not there yet, Gómez Pinchetti warns: many technical complexities are yet to be solved, from growth under industrial conditions to mordants and fastness. It’s still a long road ahead for our Misses Synechococcus, Erythrotrichia, Arthrospira (spirulina!), Leptolingbya, Nostoc, Hallochlorella, Sarcinochrysis, Caespitella, Gracilaria, Grateloupia, Phorphyra, Osmundea, Bifurcaria and Ulva.

(I know. We need pet names for them if we must consciously invite them into our lives and wardrobes.)

If it works out though, this would be an entirely new relationship with seaweed, one forged out of human ingenuity and algal resourcefulness.

Even more important, this could spell the end of mermaids having to swim naked: we could teach them how to dress themselves in all the colours of the sea.

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Many thanks to Ruth Jaen Molina, Tamara Rodríguez Ramos and Juan Luis Gómez Pinchetti for their invaluable help in providing information for this article. More information may be found on the project’s website. Images supplied by the Sea Colours team.

More of Aina’s writing is available to read on her website and blog.