A novel nutrient upwelling solution to enable large-scale offshore aquafarming

To restore our climate and achieve a Net-Zero society by 2050, we need to be able to sequester at least as much CO2 as we emit. There is insufficient land available to meet this target through planting trees, and existing carbon-removal technologies, such as direct air capture (DAC) or carbon capture and storage (CCS), are expensive and challenging to scale. Solutions capable of sequestering gigatonnes of CO2 are urgently required to heal the climate.

Sargassum seaweed represents one of nature's best candidates to solve the climate challenge. Sargassum is free-floating, has a high carbon-to-nutrient ratio, doubles in size every two weeks, and can grow with almost unlimited scale. Carbon accounts for 30% of the dry mass of Sargassum, and it can sequester 10x more CO2 than phytoplankton with the same amount of nutrients.

Furthermore, Sargassum extracts can replace fossil-fuel derived products as raw materials for plastics, fertilisers, and fuels.

Seafields is developing modular offshore aquafarm technology to sustainably grow Sargassum at scale. The aquafarm infrastructure comprises low-cost floating barriers made from sustainable materials and contained by offshore currents or through tethering to existing offshore infrastructure. The seaweed biomass will be harvested, processed onboard a mother-ship to extract valuable products, and the carbon-rich residues will be baled and stored in the deep ocean for long-term (\>1,000-years) carbon-sequestration.

The Innovate UK project will develop a groundbreaking scientific test facility, enabling the validation of scalable infrastructure required to continuously supply the surface aquafarm with nutrients abundant in deeper layers of seawater. The project will accelerate economically feasible offshore aquafarming and is a key step in our mission to sequester 1Gt/year of CO2 by 2035\.

Seafields will be the first to domesticate Sargassum, becoming a global leader in a carbon-capture market forecast to reach $4.4 trillion by 2050 whilst having a major positive impact on our climate and ocean biodiversity.