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Research article2022Peer reviewedOpen access

Contribution of soil algae to the global carbon cycle

Jassey, Vincent E. J.; Walcker, Romain; Kardol, Paul; Geisen, Stefan; Heger, Thierry; Lamentowicz, Mariusz; Hamard, Samuel; Lara, Enrique


Soil photoautotrophic prokaryotes and micro-eukaryotes - known as soil algae - are, together with heterotrophic microorganisms, a constitutive part of the microbiome in surface soils. Similar to plants, they fix atmospheric carbon (C) through photosynthesis for their own growth, yet their contribution to global and regional biogeochemical C cycling still remains quantitatively elusive. Here, we compiled an extensive dataset on soil algae to generate a better understanding of their distribution across biomes and predict their productivity at a global scale by means of machine learning modelling. We found that, on average, (5.5 +/- 3.4) x 10(6) algae inhabit each gram of surface soil. Soil algal abundance especially peaked in acidic, moist and vegetated soils. We estimate that, globally, soil algae take up around 3.6 Pg C per year, which corresponds to c. 6% of the net primary production of terrestrial vegetation. We demonstrate that the C fixed by soil algae is crucial to the global C cycle and should be integrated into land-based efforts to mitigate C emissions.


biogeography; microbial photosynthesis; net primary productivity (NPP); photoautotrophs; soil carbon (C) cycle; soil microbiome

Published in

New Phytologist
2022, Volume: 234, number: 1, pages: 64-76
Publisher: WILEY

    UKÄ Subject classification

    Soil Science

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