The power and potential of seaweed
Seaweed is something we’re all familiar with from trips to the beach, but its potential as a business opportunity for the aquaculture industry is now emerging.
Aquaculture is simply farming underwater – whether that’s salmon or seabass, or more increasingly, seaweed. We’re following the development of seaweed aquaculture and exploring some exciting opportunities for this versatile product.
What can seaweed be used for?
Cosmetics
Kelp, nori, and bladderwrack are all popular seaweeds used in cosmetics
Credit: Leighann Blackwood/Unsplash
Medicine
Seaweed has also been used for medicinal purposes for centuries. Its rich nutrient content makes it a versatile treatment for respiratory ailments, arthritis, colds, and influenza.
Seaweed baths are also used to relieve muscle and joint pain, eczema, and reduce swelling.
In addition, seaweed-derived carrageenan and algins are used in pharmaceutical products as binders, stabilizers, and emulsifiers, and polysaccharides from seaweed are used for wound dressings.
Biofuel
Seaweed is a promising source of biofuel. It's well-suited to anaerobic digestion, a process used to make biogas, and fermentation, which makes ethanol. Seaweed biofuel is a renewable energy source that doesn't contribute additional emissions to the environment, as the carbon it releases is already drawn from the atmosphere. This makes seaweed-made biofuel a low-carbon alternative.
Edible water capsules
Seaweed can also be used to create eco-friendly packaging alternatives. Notpla, a sustainable packaging company, has developed edible water capsules called 'Ooho,' made from seaweed.
Ooho is an edible, biodegradable, and tasteless membrane that can be used to store water and other liquids in small capsules or bubbles. These capsules are ideal for single-use servings at events and festivals, where they could replace the millions of plastic bottles used each year.
Burger boxes and sauce sachets
Takeaway food containers, burger boxes, sauce sachets and oil pipettes are some more of the packaging alternatives to plastic.
Seaweed grows quickly – with some growing up to 60cm per day, it doesn’t compete with food crops and doesn’t require fresh water or fertiliser, making it a great renewable resource.
Packaging made from seaweed can be composted at home and breaks down in 4-6 weeks, compared to the hundreds of years it can take plastic to. Some of the packaging is also edible, further reducing waste
Food
Seaweed has long been used as a nutritious food source and is becoming increasingly popular in Western cuisine. It's low in calories and high in vitamins, minerals, and antioxidants, making it a healthy addition to any diet. It can be used in salads, soups, and sushi, and is a popular snack in many cultures.
Onigiri is a popular dish that uses seaweed as a main component
Credit: Kat/Unsplash
Where could it be farmed?
Co-locating seaweed farms with offshore wind
As the UK strives to achieve its net zero emissions target by 2050, seaweed aquaculture could be a solution to easing the competition for space experienced in coastal waters.
Seaweed is just one species that could be grown in conjunction with offshore wind farms, providing a unique opportunity for co-location with existing structures like offshore wind turbines.
Multi-species aquaculture
In some aquaculture systems such as net pens in seawater, it is possible to grow different species, such as fish, shellfish and seaweed, next to each other.
The combination of fish, shellfish, and seaweed are complementary, meaning the waste generated by the finfish can be used as a food source for the shellfish and seaweed species. This results in cleaner surrounding water and three commercial species being produced rather than one.
Rewilding
Rewilding or restorative aquaculture refers to the practice of farming species to help recover biodiversity, rather than farming for profit.
A good example of this in the UK is the Sussex Kelp Restoration Project which aims to restore 200 km2 of the once-abundant kelp forest along the Sussex coastline using kelp farming techniques.
If successful, the project could increase seabed diversity, create new habitat and nursery grounds particularly of bass, black seabream, and cuttlefish. It could help with the regeneration of natural oyster beds, create a better food web structure, offer increased coastal protection, and lock in carbon.
A kelp forest found around Orkney, Scotland
Credit: Alison Moore
What else can seaweed do to help us?
Producing oxygen and absorbing carbon
Seaweed plays a vital role in producing oxygen and absorbing carbon, making it a valuable resource in our changing climate. It produces 70% more oxygen than land plants and absorbs carbon more effectively than trees, storing an estimated 175 million tonnes of carbon each year.
Seaweed can also remove nutrients from water, making it an environmentally friendly tool to improve water quality, and helps prevent coastal erosion by buffering strong waves and currents. Kelp forests are particularly effective in lessening the impact of waves and protecting coastlines.
Cleaning up water and absorbing nutrients
Seaweeds can play an important role in removing nutrients from the surrounding water. Nutrients such as ammonia, nitrate, phosphorus and nitrogen, which are found in agricultural run-off, industrial and sewage water discharge, can all be absorbed by seaweed.
Farming seaweed in areas where these discharges occur, could be used as an environmentally friendly tool to assist with improving water quality.
The seaweed around Farne Lighthouse in England protects the island from coastal erosion
Credit: Kirsty Andrews
Funding from the Levine Family Foundation
We are extremely grateful for the funding the Levine Family Foundation provided us, which enabled us to kickstart a seaweed aquaculture programme of work for the UK and increase our understanding of how to guide the industry to develop in a sustainable and environmentally friendly way.