Geoscience: Biological soil crusts reduce dust blowing in the wind

Biological soil crusts — a community of microbes, lichens and non-vascular plants living on the soil surface that is primarily located in drylands — may reduce global dust emissions by 55%, preventing the release of approximately 700 million tonnes of dust every year, according to a paper published in Nature Geoscience. These findings highlight the importance of biocrusts in the management of global environmental change.

Biological soil crusts or biocrusts are comparable to the living skin of global drylands, covering 12% of land surface worldwide and reducing soil erosion by increasing soil stability. This stabilization effect can reduce dust emissions in small-scale wind-controlled experiments. However, the extent to which biocrusts affect the global cycle of atmospheric dust — a type of aerosol with significant effects on our climate — is, as of yet, unknown.

Considering this stabilization effect, Emilio Rodriguez-Caballero and colleagues estimate the impacts of biocrusts on the global dust cycle and correspondingly, the climate, under current and future conditions. The authors reveal that biocrusts greatly reduce global dust emissions and deposition, leading to an overall reduction in the dust burden of 55%. Subsequently, biocrusts may impact the climatic effects of dust in a comparable manner as the direct effect of aerosols from human activity. However, if the loss of biocrusts — induced by climate change and land-use intensification — is as severe as expected, in 2070, the authors predict that the global dust burden will increase by up to 15%.

The authors conclude that the influence of biocrusts on global dust cycling and associated climatic effects have important implications for human health, biogeochemical cycling, and the functioning of ecosystems. Therefore, they state, these findings suggest the need to consider biocrusts as a key player in global change.