05/08/2026
Seaweed captures carbon. But does it actually store it?
Seaweed absorbs carbon dioxide while it grows, but this does not automatically make every seaweed farm a permanent carbon sink.
A study published in Marine Pollution Bulletin in April 2026 examined sediments near a kelp and mussel farm in the United Kingdom. Researchers found limited carbon accumulation from the cultivated kelp. Another 2026 study showed that iron availability and competition with phytytoplankton can significantly reduce the estimated carbon-removal potential of large-scale seaweed cultivation.
The lesson is important: location, nutrients, water circulation, harvesting and the final use of the biomass all influence the real environmental impact of a seaweed farm.
This is exactly why SEAGROW is focused on measurement rather than assumptions.
In Galway Bay, the project will deploy 6,400 metres of cultivation rope as a living laboratory. Researchers will assess nutrient uptake, biodiversity, carbon storage and the full life cycle of cultivated kelp. SEAGROW will also test an integrated system combining seaweed and scallop farming.
Seaweed has enormous potential, but credible regenerative ocean farming must be supported by field data.