Clouds reflect in the sea with seaweed plantations stretching along the coastline.

The seaweed industry is growing rapidly, but climate change could threaten the livelihood of those who work in it. Image © Cavan-Images/Shutterstock.

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Scientists plan ‘seaweed breakthrough’ to restore threatened species

Seaweeds play a vital role in the modern world, but their existence is under threat.

As climate change, disease and invasive species puts the algae under pressure, an international team of scientists has just started work on a project to protect and restore seaweed stocks.

Is it time to say so long to sushi, and later to laverbread?

Around the world, the seaweed industry is becoming bigger than ever. In the past 20 years, seaweed supply has tripled as demand for its use in food, medicines and even building materials has risen.

However, the impact of rising temperatures, pollution, overharvesting and invasive species could make seaweeds 70% less common by 2100.

With fewer seaweeds, some of the planet’s most productive ecosystems will be lost, hindering our ability to fight climate change and world hunger. A new project, named GlobalSeaweed-SUPERSTAR, hopes to prevent this by putting together new plans to protect and restore the marine algae all over the world.

Project leader Professor Elizabeth Cottier-Cook says, ‘Despite their significant ecological and economic importance, wild seaweeds receive minimal or no protection through policies or legislation globally.’

‘We’re not just looking at a looming biodiversity crisis; there is an entire economy that supports millions of families in developing nations. Women, who are integral to seaweed cultivation, are also able to be economically active in this industry, in areas where few opportunities exist.’

‘We hope to set out policies that can be adopted at the highest intergovernmental level to help safeguard wild stocks and, ultimately, safeguard the global seaweed farming industry.’

The team hope to unveil their strategy, or ‘Seaweed Breakthrough’, at the COP31 climate summit in 2026.

Shoals of fish swim between towering kelp.

Seaweed provides the structure of marine habitats, and is especially important in cooler seas. Image © Andrew B Stowe/Shutterstock. 

Big business

Seaweeds are some of the most important marine species on Earth. They provide shelter for sea life, protect coastlines from erosion, and take carbon dioxide out of the atmosphere, as well as providing food for a wide range of animals.

The properties which make them so useful in the natural world also make them valuable in the business world. Particular attention has been drawn to the sustainability of seaweeds, as they grow very quickly without the need for a lot of fertiliser or excess water.

As a result, these algae are rising stars of the modern day, with a wide variety of uses from agar to energy production. The seaweed industry is currently worth around $15 billion, but is expected to reach $25 billion by the end of the decade.

The vast majority of the industry is based in Asia where almost all seaweed is grown in farms. Major crop species include Eucheuma in tropical regions, and Japanese kelp and nori species in more temperate waters.

Elsewhere in the world, seaweed production heavily relies on harvesting wild seaweeds, with more than 90% of the output taken directly from the environment.

A pair of chopsticks holding green wakame seaweed above a bowl.

As well as being a popular food, wakame has become an invasive species in Europe. Image © Lesterman/Shutterstock. 

In principle seaweed farming is better for the environment than growing food on land, but in the past it has caused significant problems. Wakame, for instance, was accidentally imported into Europe and has now become an invasive species, while the overharvesting of other wild seaweeds can threaten their populations.

Alongside threats such as climate change and disease, unsustainable harvesting is now starting to make its impact known. While seaweeds still appear to be very abundant, recent research in the UK found that some species have experienced large losses which hadn’t previously been noticed.

Professor Juliet Brodie, a seaweed specialist from the Natural History Museum who is part of the GlobalSeaweed-SUPERSTAR team, says, ‘Seaweeds are often taken for granted, and I think people don’t really realise how important seaweed habitats are.’

‘We’re only now getting the data to confirm what we’ve heard anecdotally for the past 10 to 20 years, that seaweeds are in decline. Even then, there’s still a lot more that we need to find out.’

The ubiquity of seaweeds in shallow seas means that they are often overlooked when it comes to protecting the ocean. While some important seaweed sites may end up in marine protected areas (MPAs), seaweeds are almost always protected because of other species.

GlobalSeaweed-SUPERSTAR aims to change this by putting together action plans to protect seaweeds, as well as supporting the seaweed industry to grow sustainably.

A photo showing a seaweed farm beneath the waves next to a tropical island.

Breeding new heat and pest-resistant cultivars can help seaweed farms to thrive. Image © Dudarev Mikhail/Shutterstock. 

Save our seaweeds

The project is ambitious, including aspects of policy, experimental research and public outreach. But even seemingly simple proposals, such as agreeing on seaweed names, can be a challenge.

‘Seaweeds can be difficult to identify, as they are morphologically very variable,’ explains Juliet. ‘This is compounded by their wide variety of lifestyles.’

‘Knowing what species live where is critical in conservation, but at the moment seaweed names are a bit of a mess. Around the world many species aren’t being identified accurately enough to protect them.’

By accurately identifying where different seaweeds live, the project hopes to highlight new seaweed hotspots which can then be protected by new and existing MPAs. They also hope to expand their work with local people to build up a better picture of how seaweeds are faring.

‘I’m keen to encourage people on the ground to get involved in seaweed conservation through community science projects,’ Juliet says. ‘This can then be backed up with wider government support, so that local people can take ownership of their region’s resources.’

‘I’d also like to explore what I call ‘ethnophycology’, where we use the knowledge of local people to find out more about seaweeds. This might include, for instance, talking to older people in a community about their memories of seaweeds in the past.’

‘By adding up all the insights from these conversations, it can provide a baseline for seaweeds in the past, and contribute to a better understanding of how things are changing.’

Iridescent light reflects off a brown seaweed.

It's hoped that educating the public about charismatic seaweeds like Iridaea, more people will become passionate about these marine algae. Image © Juliet Brodie.

This information will help the researchers develop and test new strains of seaweed, which they hoped will make more efficient crops. The team are looking to test more heat-tolerant and pest-resistant seaweeds that are better adapted for the challenges of the twenty-first century.

The project is set to run for the next three years, with the team hoping that their work will also inspire people to pay more attention to the humble yet incredibly valuable seaweeds.

‘It would be great to see people being able to recognise a few key types of charismatic seaweeds, such as the iridescent Iridaea or marvellous Padina species with their funnel-shaped lobes and white calcite coating,’ Juliet says.

‘Getting more people to appreciate seaweeds would go a long way towards helping to protect them.’