Abstract

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.

Keywords

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

SLU Authors

• Kardol, Paul

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Ecology
Soil Science


Publication identifier

DOI: https://doi.org/10.1111/nph.17950

Permanent link to this page (URI)

https://res.slu.se/id/publ/116109