The promise of seaweed

by Thomas Jensen

Sharing insights on a burgeoning industry at Seagriculture 2021

This article was featured in Eurofish Magazine 6 2021

It’s not enough that seaweed helps produce 50%–70% of the world’s oxygen. The various species of seaweed (72,500 known species and an unknown number of undiscovered species) can be used to produce food for humans, feed for animals and fish, pharmaceuticals, bioplastics, fertilisers, biofuels, and much more. Seaweed protects and regenerates ocean ecosystems, not to mention decarbonising the atmosphere. Yet, so far, seaweed’s potential has been largely overlooked.

At the 10th edition of the Seagriculture Conference, held 15–16 September 2021, more than 25 speakers from 11 countries focused on the technical aspects of wild seaweed harvesting, farming, and production, as well as related aspects such as ecosystems, marketing, supply chain, sustainability, and future developments. The conference, attended online by more than 180 participants from 27 countries, gave entrepreneurs and academics the opportunity to showcase their services, products, and research.

The conference especially underlined the innovative character of today’s seaweed industry. Felix Leinemann, DG Maritime Affairs and Fisheries, presented the “European Union—Seagriculture Algae Innovation Award” to Taiwan (gold), Spain (silver), and Malaysia (bronze). Sixteen innovations were submitted from around the world, 40% of which were submitted from Europe. By funding the Seagriculture Innovation Awards, the European Commission highlighted its commitment to the expansion of a thriving, regenerative algae industry. The conference made it clear that, in Europe, seaweed is indeed underappreciated and not fully understood, and that closing these gaps is a large part of the work yet to be done. The conference also made it clear that discovering seaweed’s many possibilities takes a pioneering spirit.

Global seaweed industry is set for double digit growth

The global seaweed industry is growing. According to the Food and Agriculture Organization of the United Nations, the global market has more than tripled between 2000 and 2018, reaching 32.4 million tonnes of production with a value of USD13.3 billion (EUR11.3 billion) in 2018. According to Seaweed for Europe, a coalition to advance and scale a sustainable and innovative seaweed industry in Europe, the global industry is expected to expand by 12% per year until 2024. Many market forecasts expect a double-digit compound annual growth rate for the next 5–10 years. Most of the world’s seaweed, however, is farmed in Asia, and Europe, the top importer of seaweed products (USD613 million in 2016), is clearly lagging behind. The nascent European seaweed industry must accelerate and significantly grow its production capacity.

The European seaweed industry is still in its infancy. Of the 223 companies sampled by Seaweed for Europe, 123 (55%) were created less than 10 years ago. It is also small scale; 130 of the 223 companies (58%) have fewer than 10 employees. Most (188 or 85%) of the companies in the industry have an advanced technology readiness level of at least 8 on a scale of 1–9, and are already generating revenues. This indicates a strong momentum for the European seaweed industry. Seaweed for Europe forecast that, from the 300,000 tonnes of fresh weight seaweed produced today, more than 8 million tonnes of fresh weight seaweed will be produced in 2030, with a value of up to EUR9.3 billion, and generate 85,000 jobs.

Currently, more than 50% of the companies concentrate on human-food and animal-feed applications. However, as companies begin to explore alternative applications, they are developing more diverse portfolios. It is a perfect time to scale up the industry. Europe’s cold and nutrient-rich waters provide ideal growing conditions, and the industry in Europe is ideally positioned to expand as the EU recognises seaweed’s potential and its strong harmony with the European Green Deal. The industry will benefit from growing political support at global, national, and local levels as well as increasing interest from large corporations, which are investing in seaweed.

An exciting range of applications

Seaweed (macroalgae) grows in a variety of forms and colours in the ocean as well as in freshwater environments. Its biochemical composition and properties make seaweed a valuable material, and its range of applications is growing as current R&D technologies are refined and new discoveries are made. They include food products for humans, animal feed, cosmetics, bio-based chemicals for various industries, fertilisers, biofuel, and high-quality building insulation, among others. Many of these applications provide sustainable, low-carbon alternatives to existing options and offer many environmental and health benefits. A strong European seaweed industry will boost economic growth, by channelling investment into coastal communities, and create jobs. Seaweed cultivation is also interesting for what it doesn’t do. It doesn’t require cleared land for cultivation. It doesn’t make demands on the supply of freshwater, which is becoming scarce in parts of the world. It doesn’t require fertiliser, which causes pollution and eutrophication and is toxic to humans and wildlife.

Feeding humans, animals, and fish

Seaweed has long been a source of human nutrition. It is rich in minerals, such as calcium, iron, vitamins, and polysaccharides, and some species contain large amounts of amino acids, proteins, and unsaturated fatty acids. Further, it is low in calories and rich in dietary fibre, indicating substantial health benefits, including reduced blood pressure and improved digestive health. The bioactive compounds in seaweed might help stabilise blood sugar levels in the management of diabetes. According to a report by the Memorial Sloan Kettering Cancer Center, other health benefits may include boosting the immune system, reducing inflammation, preventing cancer, lowering blood pressure, preventing blood clots and infection, and fighting obesity. More study is required to confirm all of these claims, but serious scientific research is continuing.

Many westerners associate seaweed with Asia, where it is part of the food culture and plays a role in Asian medicine. For example, seaweed is an integral part of Japanese cuisine, including nori (wrapped around sushi), wakame (in miso soup), Mozuku (a side dish), and kombu (the broth in soup). Although Europeans might view seaweed as a food of the future, they may be surprised to learn that inhabitants of Western Scotland have consumed a variety known as dulse since at least the sixth century.


Seaweed plays a central role in providing critical ecosystem services in the ocean. It forms an integral part of a complex foodweb and offers habitat, nursery grounds, and protection from predators to fish, invertebrates, birds, and marine mammals. It is a natural protector, restraining the ocean’s force by dissipating wave energy and preventing coastal erosion. Seaweed also absorbs a range of excess inorganic nutrients from the ocean, including nitrogen and phosphorus.

From CO2 to seaweed biomass

In his presentation, Stefan Kraan, from The Seaweed Company, Ireland, noted that seaweed farming is instrumental in converting and sequestering CO2, as well as supporting ocean regeneration. Because oceans cover 70% of the planet, ocean ecosystem restoration has the greatest potential—greater than traditional land ecosystems, such as forests—to capture CO2 from the atmosphere. Seaweed uses photosynthesis to turn CO2 into seaweed biomass, the carbon of which is sequestered in their underlying sediments in underground and below-ground biomass and in dead biomass. This process is known as carbon sequestration. Seaweed grows extremely quickly, so it can absorb CO2 at a phenomenal rate. Once the CO2 is locked into seaweed biomass, it can be harvested for use, it can sink to the seabed, or it can be stored underground where the excess CO2 originally came from.

Mr Kraan also noted the pressing problem of fixing organic carbon in soil for longer durations. The Seaweed Company has been experimenting with a bio-growth stimulant product made from seaweed that fixes an extra 11 tonnes of carbon per hectare in the soil. This translates to approximately 40 tonnes of CO2. He admits that it’s not a huge amount, but it
adds up.

A weapon in the fight against climate change

Seaweed used as a livestock feed may offer a way to reduce methane emissions produced by livestock. Methane, produced as a natural consequence of the ruminal digestion, is a potent greenhouse gas. Presenters Deepak Pandey and Ying Yen, PhD students at Nord University, Norway demonstrated that hot water blanching can improve the rumen degradability of selective brown species of seaweed with high total polyphenol contents (TPC), although not of red and green species with lower TPC contents. Ying Yen also reported on work done in post-harvest preservation. Usually, seaweed is dried or frozen, which requires a great deal of energy and is quantity sensitive. Her work in ensiling, a process of preserving wet plant material by sealing the seaweed either in a pit or in a barrow, ensures anaerobic conditions, which demands less energy.

Tamara Singer of Lofoten Seaweed, Norway, pointed out that many Europeans are unaware of seaweed’s benefits—consumers must be persuaded to buy seaweed and taught how to use it. Owing to a fragmented value chain, a lack of awareness outside the industry of seaweed’s potential—in particular among policy makers—and limited investment, the European seaweed industry is still far from attaining its full potential. For example, Europe has focused mainly on harvesting natural seaweed, but a maximum sustainable production level has been reached. To expand, the industry must move towards sustainable farming.

Ms Singer and her business partner Angelita Eriksen practise wild harvesting. This gives them access to a whole range of species for which farming technology doesn’t exist. Ms Eriksen emphasised the need—and duty—that wild harvesters have to protect and monitor their environment. Sustainable harvesting principles include cutting the seaweed at a height that encourages it to grow back and rotating among patches, so that patches are not overexploited. They map each gram of seaweed that they harvest and add the results to a database to ensure that they work consistently from year to year.

More than one presenter echoed the sentiments expressed by Angelita Eriksen: It is crucial to press regulatory bodies to establish regulations that are not overly restrictive. Governments need to support industry development with policies that encourage aquaculture and streamline the licensing process. Out-of-date, restrictive policies must be updated. Currently, many agencies have no framework for seaweed aquaculture. For a seaweed carbon sequestration market to exist, someone must be willing to pay to store carbon in seaweed. Currently, there is no carbon credit exchange market for seaweed.

The EU’s algae initiative will help boost the sector

A recent public consultation by the European Commission revealed a broad interest in the sustainable production, consumption, and use of algae and algae-based products in the European Union. An overwhelming majority of EU and non-EU citizens, research institutions, NGOs, business organisations, companies, and public authorities confirmed their wish to see the EU support the development of the EU algae sector and help it become more competitive and sustainable. Based on this consultation and further preparatory work in the course of 2021, the Commission will now identify effective actions, new opportunities, and the needs of the sector to be considered within the forthcoming EU Algae Initiative. Because of algae’s small carbon and environmental footprint, increasing its production and use will help achieve the objectives of the European Green Deal.

Seagriculture EU, the European edition of Seagriculture, will be held on 29–30 June 2022 in Bremerhaven, Germany. A new, North American edition will be added next year. Seagriculture USA 2022 will be held 7–8 September in Portland, Maine. The state of Maine is one of the hot spots for seaweed farming in the United States.

William Anthony

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