What do citizens, fertilizer, animal feed, packaging materials, fuel, clothing and a way to remove CO2 from the air have to do with each other? As crazy as it may sound, seaweed is the common factor here. 98 percent of our food is produced on natural ground, while as much as 71 percent of the earth’s surface consists of seas and oceans. Should we be able to utilize water for other purposes – such as food production – then there is much to be gained here. And what thrives in the water, with CO2 as a nutrient? Exactly: seaweed! Millions of years ago, before plants and trees existed at all, tiny single-celled microalgae lived in the water. From this, thousands of species of seaweed have evolved, which are packed with proteins, minerals and vitamins. In other words, healthy for both humans and animals, especially as research has shown that cows that eat certain seaweeds produce more milk and are healthier. Cows fed with seaweed also emit less methane, which helps combat climate change! All over the world, startups are beginning to see the potential of the green-brown alga and discover its seemingly countless possibilities.
Figure 1: Seaweed coming from experimental farm ‘North Sea Innovation Lab’. Source: https://www.groene.nl/artikel/zeewier-komt-met-een-belofte
Let’s take a look at the numerous uses seaweed has to offer us.
Seaweed as food
In its most recognizable application: people know seaweed as the dark wrapper around their sushi snack. But did you know that there are now seaweed burgers, seaweed bread, seaweed bacon, seaweed pasta and seaweed salmon? Seaweed is packed with protein and could play a major role in the protein transition. After all, producing meat emits an incredible amount of CO2, and the green strands from the sea can provide humans and animals with the same nutrients as a replacement for meat. Calculations show that seaweed cultivation in an area the size of twice Portugal could provide the entire world population with all necessary protein. Large-scale cultivation in the North Sea by 2030 should even provide the amount of protein equivalent to 5.6 million chickens. The Dutch Weed Burger has been making food from seaweed since 2012, with their burger consisting of soy and the seaweed species kombu. Founder Mark Kulsdom says, “Our planet is being depleted by the large-scale meat and dairy industry. There is less and less usable farmland to feed all those animals, due to loss of nutrients and soil erosion. At the same time, there are more and more people on earth. To feed them, we need future-proof proteins.’
Figure 2: The Dutch Weed Burger. Source: https://dutchweedburger.com/ons-eten/
Seaweed contains many minerals and hormones, which are very useful for plants and soil life. Plants grow quickly as a result, which is why seaweed is widely used as a fertilizer.
We use a lot of single use plastics for things like sauce pouches, salad containers and “pods” for washing machines. Traditional plastic food packaging has two major drawbacks. First, they contribute to plastic pollution in the environment because they do not break down. Second, they often have condensation on the inside, which causes mold. Packaging made from seaweed is sustainable and biodegradable, so you can just throw it in the garbage. Another great advantage of seaweed-based packaging is that food dries out, preventing mold and keeping it unspoilt much longer. This prevents food waste. In addition, seaweed-based packaging is even edible and thus suitable as livestock feed. Due to its digestibility and biodegradability, neither animals nor the environment suffer. Unfortunately, the production costs of traditional plastic are much lower because of the cheap fossil fuels from which it is made. If multinationals such as Unilever and Nestlé ever embrace seaweed packaging, we will move toward a circular economy, as the biodegradable packaging enters the natural cycle.
Figure 3: Packaging made from seaweed. Source: https://www.plasticsoupfoundation.org/2021/02/verpakkingen-van-zeewier-eindelijk-een-echte-oplossing-voor-de-plasticsoep/
Seaweed as CO2 storage
As mentioned earlier, seaweed absorbs a lot of CO2 as it grows. Ten tons of wet seaweed equals one ton of CO2 absorbed. On one hectare you can grow 150 tons of seaweed. This means you can absorb 15 tons per hectare and 1500 tons of CO2 per square kilometer. If enough such plantations were established, enough CO2 could be taken out of the water, which means that the oceans could also take more CO2 out of the air. One drawback: when seaweed rots, the stored CO2 is released again. Solution: by sinking the seaweed into the deep sea and letting it rot there, the CO2 can no longer get into the upper layers of the water and therefore no longer into the atmosphere.
There is also much to be gained in the energy transition by using seaweed as a feedstock for biomass and biofuels. Calculations by the Netherlands Environmental Assessment Agency (PBL) show that by 2050 we will need 1,600 Petajoules of biomass as fuel to produce electricity. Seaweed has the potential to take up a third of this. The brown strands can be split into sugars, proteins and minerals. These substances are then reprocessed into semi-finished products from which liquid fuel can be made. KLM also seems to see the potential. Ever since 2008, they have had a desire to fly on algae. Energy producer ExxonMobil aims to achieve this by 2025 by producing ten thousand barrels of algae fuel per day. In 2009, they jointly invested six hundred million dollars with biotech company Synthetic Genomics to convert algae to fuel. By 2017, they had produced a microalgae that was forty percent oil!
The apparel industry is the second most polluting sector after the oil industry. As much as 8 percent of global greenhouse gas emissions come from the production of clothing and shoes. The industry is also responsible for surface water pollution and extreme water use. One T-shirt already requires 2,700 liters of water. Scottish Jasmine Linington designed a clothing collection made from seaweed. In turn, the American company Metawear has developed textile dyes based on seaweed, so that coloring clothes can also be sustainable.
Figure 4: Jewelry made from seaweed. Source:https://www.dezeen.com/2019/08/07/jasmine-linington-seaweed-girl-couture-clothing/
Although the possibilities with microalgae seem endless, serious consideration must be given to potential risks involved. On a small scale, seaweed cultivation has positive effects on biodiversity. But the alga only grows for six months and then disappears with the harvest. Furthermore, large monocultures quickly attract pests and diseases, just as in agriculture. Is there a risk that entire ecosystems will be disrupted by cultivation? Koen van Swam of the North Sea Farm Foundation says there are two ways to counteract that. One is that seaweed grows in the winter and the harvest takes place in April or May. By allowing other species to grow in the summer, you get a nice base for sea life. Another important solution is that the anchoring of the plant is nature-friendly. Zairah Khan, founder of research foundation BlueO2 indicates that seaweed cultivation is a complex product that still needs a lot of research. For example, are there enough nutrients in the water? Despite the legion of sustainable uses for seaweed, there is certainly still much to be done in terms of scaling up and cost reduction.
Seaweed Innovation Report 2022