Food, fuel and more will be produced in sea farms of future

Meet the farm of the future, where common seaweed is being upgraded from an environmental problem to a valuable natural resource and raw material

“The fact is that algae can absorb nitrogen from the water as effectively as a wastewater treatment plant,” says Gröndahl, a KTH Royal Institute of Technology researcher and head of the Seafarm project, which converts algae into eco-friendly food, medicine, plastic and energy.

The excessive fertilisation (eutrophication) of our seas results in an over-production of algae, commonly known as seaweed. Bathing beaches become unusable on account of algae blooms and entire ecosystems can be threatened.

“But, in our research, we turn the argument on its head and see algae as a resource. We collect excess algae along the coasts and cultivate new algae out at sea,” Gröndahl says.

Already, seaweed is getting scooped up from the Baltic Sea, along Sweden’s southern coast, in order to be converted to biogas. The coast is rich with the seaweed. The city of Trelleborg estimates that its beaches host an excess of algae that is equivalent to the energy from 2.8 million litres of diesel fuel.

Almost three quarters of the earth’s surface is covered by sea, and the seas possess as great a production capacity as the land. At the present time, humankind utilises 40 per cent of the production from land-based ecosystems whereas only 1 per cent of the seas’ ecosystems are currently utilised.

Unfortunately, this percentage at present consists largely of ruthless exploitation; where the fishing industry trawls up every living thing and hoovers the sea bottoms. “We really need new solutions, such as harvesting the excess algae for fuel and cultivating new, pure algae for special products and foodstuffs,” Gröndahl says.

Gröndahl points out that algae contain vitamins, amino acids and minerals, indeed the entire list of the periodic elements, including iron. Algae may be eaten directly or cooked; and in recent years an interest in algae products in foodstuffs has increased in Sweden, thanks in part to the popularity of Asian food culture. Even spices and cooking oil can be produced by algae.

The brown algae known as sugar kelp (Saccharina latissima), for example, contain up to three times as much sugar as sugar beet. “Of course, it’s unwise to burden the earth with oil palm and sugar beet cultivation when corresponding products can be produced in an ecologically sustainable way from algae,” explains Gröndahl.

Algae may, in the future, be an ingredient of animal feed to replace the environmentally damaging fish meal which is common in pig and poultry diets.

Furthermore, salmon today is fed with fishmeal from wild caught fish, and calculations show that no less than 5 kg of wild fish go to produce 1 kg of farmed fish.

“Clearly, it’s not a good idea to feed fish with fish. Algae feed, in this case, will be of great benefit for the environment,” he says. “What’s more, we’re counting on Seafarm’s cultivation of algae being able to favour the marine environment as a whole, since they form secondary reefs in free bodies of water. This sort of reef attracts fish and other animal species.

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