Halogenated compounds in seaweeds – A new market opportunity for the UK seaweed industry (FS109)

Project Outcome:

Development of seaweed as a dietary supplement to cut emissions of methane, a greenhouse gas, from cattle and sheep has centred on Asparagopsis, a seaweed native to semi-tropical waters in the southern hemisphere. But do seaweed species native to, or common in, UK waters exert similar effects?

We sampled almost 40 species of seaweed from the Scottish coast and tested their effects on methane at laboratory scale. None of the seaweeds matched Asparagopsis as a methane mitigator, and none contained significant quantities of the chemicals known to account for the effects of Asparagopsis.

However, a small number of UK-sourced species did show more modest, but potentially valuable, effects on methane production, with reductions of up to 30%. So, while UK seaweeds are not a ‘magic bullet’ for methane mitigation they may still have a role to play, especially as seaweed supply chains develop and expand to meet demands for seaweed for food, fertiliser, and other industrial uses. Further studies are needed to confirm that beneficial effects seen in the laboratory are also seen when seaweeds are fed to cattle and sheep.