Slime for the climate, delivered by brown algae

Dec 26, 2022

In form of fucoidan, brown algae could remove up to 0.55 gigatons of carbon dioxide from the atmosphere every year

Brown algae are particularly widespread on rocky shores in temperate and cold latitudes and there absorb large amounts of carbon dioxide from the air worldwide. Photo: Hagen Buck-Wiese/Max Planck Institute for Marine Microbiology

Brown algae take up large amounts of carbon dioxide from the air and release parts of the carbon contained therein back into the environment in mucous form. This mucus is hard to break down for other ocean inhabitants, thus the carbon is removed from the atmosphere for a long time, as researchers from the MARUM MPG Bridge Group Marine Glycobiology, which is based at both the Bremen Max Planck Institute for Marine Microbiology and MARUM - Centre for Marine and Environmental Sciences at the University of Bremen now show.

They reveal that the algal mucus called fucoidan is particularly responsible for this carbon removal and estimate that brown algae could thus remove up to 550 million tons of carbon dioxide from the air every year – almost the amount of Germany's entire annual greenhouse gas emissions.

Brown algae are true wonder plants when it comes to absorbing carbon dioxide from the air. They even outcompete forests on land in this, and thus play a decisive role for the atmosphere and our climate. But what happens to the carbon dioxide after the algae have absorbed it? Researchers at the Max Planck Institute for Marine Microbiology now report in the Proceedings of the National Academy of Sciences (PNAS) that the brown algae can remove large amounts of carbon dioxide from the global cycle in the long term and thus can counteract global warming.

Fucus vesiculosus, the bladderwrack, is a perennial plant and grows up to 30 centimetres long. It clings to rocks and other substrates with an adhesive plate. The bladderwrack gets its name from the distinctive spherical gas bubbles that provide buoyancy and are clearly visible in this picture. Photo: Hagen Buck-Wiese/Max Planck Institute for Marine Microbiology

Original publication:

Hagen Buck-Wiese, Mona A. Andskog, Nguyen P. Nguyen, Margot Bligh, Eero Asmala, Silvia Vidal-Melgosa, Manuel Liebeke, Camilla Gustafsson, Jan-Hendrik Hehemann (2022): Fucoid brown algae inject fucoidan carbon into the ocean, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2210561119.

More information:

Press release Max Planck Institute for Marine Microbiology in Bremen

About the MARUM MPG Bridge Group Marine Glycobiology