Fucoid seaweed Georgie Bull

The power and potential of seaweed

3 minute read

Seaweed is something we almost always encounter when down by the coast. But what is it used for apart from a salty snack, spa treatments and sushi? We’re sharing some lesser-known uses of seaweed to show just how versatile it is

Producing oxygen and absorbing carbon

Seaweed produces more oxygen that land plants. In fact, around 70% of the oxygen we breathe comes from seaweed.

Not only does it release oxygen into the atmosphere, but seaweed also absorbs and stores carbon, helping us combat climate change.

Seaweed absorbs CO2 more effectively than trees, and it’s estimated that it stores around 175 million tonnes of carbon each year – that’s equal to 10% of the world’s car emissions. In Scotland alone, a type of seaweed called maerl stores an estimated 440,000 tonnes of carbon.

When it photosynthesizes, seaweed removes carbon dioxide from the atmosphere and converts it into sugars, which they store and use to grow. When they die, seaweeds break down and sink to the seabed, where the carbon can be stored. Here, it's less likely to be disturbed and released back into the atmosphere, making seaweed more effective at sequestering carbon than land-based plants.

Wave breaking and coastal protection

Seaweeds, particularly kelp, can help prevent coastal erosion by lessening the impact of waves. Because of their large size and dense structure, kelp forests can tolerate strong waves and currents, and buffer them. This helps protect the coast from erosion, which is primarily caused by strong waves.

Seaweeds which end up on beaches also release nutrients into dune habitats, which helps stabilise and protect sediments.

Kelp, Orkney, Scotland. Alison Moore

Kelp in Orkney, Scotland

Credit: Alison Moore


You could be using seaweed every day as part of your skincare or dental routine without even realising! Seaweed extracts are commonly used in cosmetics such as face, hand and body lotions and creams, as well as soaps, shampoos and even toothpaste.

Its properties and nutrients make seaweed a popular ingredient in skincare products.

It can regulate oil production and contains essential fatty acids and polysaccharides which can help moisturise the skin. Seaweed also has anti-inflammatory properties and contains zinc and magnesium which can combat redness. It can also reduce acne by decreasing the bacteria which forms it. Certain species are rich in amino acids and antioxidants, which promote collagen production, too.


Seaweed has been used for medicinal purposes for thousands of years.

It’s rich in vitamins, minerals, polyunsaturated fatty acids, bioactive metabolites, proteins, polysaccharides and dietary fibres, meaning it can be used for various treatments.

It’s been used to treat respiratory ailments such as sinus infections and pneumonia, as well as for tuberculosis, arthritis, colds, and influenza.

Seaweed baths are also used to relieve muscle and joint pain, eczema, and to reduce swelling.

Carrageenan and algins from seaweeds are used in pharmaceutical products as binders, stabilisers, and emulsifiers. They stabilise and thicken oral liquids such as cough medicine and are used to control the release of solid medications, too.

The dental industry uses carrageenan and algins in preparing moulds, and polysaccharides from seaweeds are used for wound dressings.

Seaweed is very high in iodine – something all vertebrates need, and has been used to combat deficiency in China.

Fucoid seaweed Georgie Bull

Fucoid seaweed

Credit: Georgie Bull


As well as producing oxygen, seaweed can produce energy – by being turned into biofuel.

Between 85-90% of seaweed is water, making it well-suited to anaerobic digestion - a process where bacteria break down organic matter in the absence of oxygen - which is used to make biogas, and fermentation which makes ethanol (a renewable fuel made from plants). Many species, like sugar kelp, also have high carbohydrate and low lignin content, which makes it great for producing bioethanol (a form of ethanol).

Although it still releases greenhouse gases when burned, seaweed biofuel is made with carbon which the seaweed has already drawn from the atmosphere, meaning that it shouldn’t contribute any additional emissions to the environment.

Edible water capsules

Seaweed can be used to create packaging with a low environmental impact and could offer an alternative to plastic.

Sustainable packaging company, Notpla, have developed edible water capsules called ‘Ooho’ which are made from seaweed –basically a seaweed water bottle. Ooho is an edible, biodegradable and tasteless membrane made from seaweed, which can be used to store water and other liquids in a small capsule or bubble.

Because of their small size, Ooho capsules are ideal for sporting events and festivals, where single-use servings are most suitable. With around 900,000 plastic bottles used in each London Marathon, think of the difference using seaweed alternatives could make.

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.

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