The Silent Guardians of Our Soil: The Unseen Power of Biocrusts

Biocrusts, the microbial assemblages that form a resilient surface layer on soils, are an unseen power in our ecosystems. These perennial, well-organised surfaces are widespread, occurring on all continents where light can reach bare soil due to a shortage of water.

The biological soil crusts cover nearly 12% of Earth’s terrestrial surface, providing invaluable services such as carbon and nitrogen fixing, nutrient recycling, and soil stabilisation. Despite their importance, researchers expect a decrease of 25% to 40% in biocrusts within the next 65 years due to climate change and land-use intensification.

Biocrusts are found on all continents, mostly in areas where water scarcity limits the growth of common plants, but where there is still sufficient moisture to support the life of these beneficial microorganisms. They are particularly prevalent in drylands, where they effectively reduce dust emissions to the atmosphere, impacting the climate and human health significantly.

As part of a decades’ worth of research, scientists at Penn State have found that the loss of biocrusts could cause a 5% to 15% increase in global dust emission and deposition.

The team studied biocrust samples from the Colorado Plateau, employing sophisticated tools such as biorthogonal non-canonical amino acid tagging and shotgun metagenomic sequencing to understand the microbial functions. They found that the biocrust community differed in species richness and composition after a simulated rain event.

Atmospheric dust can affect the earth’s climate by scattering and absorbing radiation, directly influencing the surface temperature. Rainfall, air pollution, and air quality can all be affected by dust, highlighting the impact of these tiny atmospheric particles have on human health.

The findings underscore the importance of understanding and preserving these microbial communities in our battle against climate change and in maintaining the health of our soils.