Dec. 23 () –
Brown algae have a great capacity to absorb carbon dioxide from the air, which even exceeds that of terrestrial forests, so They play a decisive role for the atmosphere and climate.
According to a study published in the journal ‘Proceedings of the National Academy of Sciences’ (PNAS), may be able to remove from the atmosphere up to 0.55 gigatonnes of carbon dioxide per year.
Researchers at the Max Planck Institute for Marine Microbiology in Germany now report that brown algae can remove large amounts of carbon dioxide from the global cycle in the long term and thus counteract global warming.
The algae absorb carbon dioxide from the atmosphere and use it to grow. They release up to a third of the carbon they absorb into seawater, for example in the form of sugary excretions. Depending on the structure of these excretions, they are quickly used by other organisms or sink to the seabed.
“The excretions of brown algae are very complex and therefore incredibly difficult to measure,” explains first author Hagen Buck-Wiese of the Max Planck Institute. “However, we have managed to develop a method to analyze them in detail “.
Using this method, the researchers examined a large number of different substances. The so-called fucoidan turned out to be especially interesting.
“Fucoidan made up about half of the excretions of the brown algae species we studied, called fucus,” Buck-Wiese explains. It is so complex that it is very difficult for other organisms to use it. Nobody seems to like it.”
As a consequence, carbon from fucoidan does not quickly return to the atmosphere. “This makes brown algae especially good helpers in removing carbon dioxide from the atmosphere over the long term: hundreds or thousands of years,” he adds.
Brown algae are extraordinarily productive. It is estimated that they absorb about 1 gigatonne (billion tons) of carbon from the air per year. Based on the results of the present study, this would mean that brown algae sequester up to 0.15 gigatons of carbon, equivalent to 0.55 gigatons of carbon dioxide, each year over the long term. For comparison: Germany’s annual greenhouse gas emissions currently amount to about 0.74 gigatonnes of carbon dioxideaccording to the Federal Environment Agency (estimate for 2020).
“And even better: Fucoidan does not contain nutrients such as nitrogen,” Buck-Wiese further points out. Thus, the growth of brown algae is not affected by carbon losses.
For the current study, Buck-Wiese and colleagues from the MARUM MPG Bridge Group Marine Glycobiology, which is based at both the Max Planck Institute Bremen and the MARUM – Center for Marine and Environmental Sciences at the University of Bremen, conducted their experiments at the Tvärminne Zoological Station in southern Finland.
“Now we want to study other species of brown algae and other places,” Buck-Wiese said. The great potential of brown algae for climate protection must be further investigated and exploited“.
