Ocean Rainforest’s harvesting vessel chugs along a fjord in the Faroe Islands

Seaweed: The food and fuel of the future?

The Faroe Islands is a part of the Kingdom of Denmark

This is a farm, but not as you know it. Banish your images of wheat and tractors; on this farm, the seaweed is the crop, and the ocean is field and furrow rolled into one. The first harvest is usually ready by late April, at which point the seaweed is sliced off the lines, collected in boxes, and brought to shore.

The company that owns the farm is called Ocean Rainforest. Its director, Olavur Gregersen, believes that seaweed farming is the future. “Some 10 years ago, a young man came to me with an idea about how the Faroe Islands could mitigate climate change by growing a forest in the ocean,” he says. “That was basically how it started.”

While The Faroe Islands have no native forests, this ocean farm is a good proxy for the ecosystem services that trees provide. Columns of seaweed absorb carbon dioxide. And as they grow, the huge organisms not only help tackle climate change but also create a pop-up habitat for marine species—just as trees absorb CO2 and provide shelter for wildlife on land.
When seaweed is left unharvested, some of the carbon it absorbs is eventually sequestered at the bottom of the ocean, where it can remain for centuries. But the point of seaweed farming is to harvest the crop. When this occurs, up to half of the seaweed produced will still wind up on the seabed because of the farming process, while the rest will be transformed into other products, including feed for livestock. Working with farmers to integrate seaweed into the diets of their animals could also lead to big environmental gains.
For example, swapping some soybeans for seaweed would mean that the planet’s supply of poultry, pork, dairy, and beef would require less arable land for feed crops. This could reduce deforestation and degradation in sensitive ecosystems such as the Amazon and the Cerrado, and decrease the need for resources like pesticides, water, and fertilizer. Scientists have also suggested that adding seaweed to the diets of cattle could significantly reduce methane emissions without diminishing milk production.

Moreover, by combating ocean acidification, seaweed farms help to protect local shellfish populations—an important source of nutrition for coastal communities around the world.
Most farmed seaweed is consumed in food, but extracts are used in a wide variety of products. Whether it is toothpaste, cosmetics, medicines, or pet food, these often contain hydrocolloids derived from seaweed, which have gelling or thickening properties.
And more products are coming, with other firms working on textiles and plastic alternatives, including biodegradable packaging, water capsules, and drinking straws.

Ocean Rainforest recently won funding from the US Department of Energy to build a similar system in California, where there’s interest in developing industrialized seaweed production for future biofuels.
As Ocean Rainforest expands, Gregersen and his team will be documenting the impact of their work on the ecosystem. But already, “we can see, just by observation, that we have an influence,” he says. “We are giving something to it, rather than taking something away.”

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