The website of NASA reads “There is unequivocal evidence that Earth is warming at an unprecedented rate. Human activity is the principal cause.” and “Scientific evidence for warming of the climate system is unequivocal”. In Europe, we have seen the hottest summer since records began.

Surface air temperature anomaly for August 2022 relative to the August average for the period 1991-2020. Data source: ERA5. Credit: Copernicus Climate Change Service/ECMWF.

But what do slime and aquaculture have to do with it?

Brown algae take up a lot of CO₂ from the air and release part of it packaged in slime (mucus). This mucus is hard to break down for aquatic animals; therefore, the CO2 contained in it stays removed from the atmosphere for longer periods.

Algae synthesise structurally complex glycans (polysaccharides, a large number of monosaccharides linked glycosidically) to build a protective barrier called the extracellular matrix. The matrix has several functions, one of them being to prevent or slow down microorganisms that try to enter living algae by excreting certain enzymes. The slime not only slows down the microorganisms but degrades and converts the microorganisms’ organic carbon back to carbon dioxide and captures it.

Researchers from the Max Planck Institute for Marine Microbiology found that an algal mucus called fucoidan is mainly responsible for this carbon removal. They estimate that brown algae could thus remove up to 550 million tons of carbon dioxide from the air yearly – almost the amount of Germany’s annual greenhouse gas emissions.

In the following steps, the group around Buck-Wiese will explore which other algae might be able to bind carbon effectively and explore the role they could play in protecting the climate.

It is very obvious how the perspective on aquaculture with new insights is changing. This requires different skills in the industry. Projects like the EIT Food-funded AGAPE project will help to ensure that the skills will match the changing needs of the industry in the workforce.