Global Change Biol. doi:10.1111/j.1365-2486.2008.01593.x (2008)


Deserts may be a much more important storehouse for carbon dioxide than previously thought, suggests a new study of the Mojave Desert in the southwestern United States. The retention of atmospheric carbon dioxide in desert soils, which cover more than 30 per cent of the Earth's surface, is often assumed to be low owing to the characteristic sparse vegetation.

Georg Wohlfahrt at the Universität Innsbruck, Austria, and colleagues from the Desert Research Institute in Nevada measured carbon exchange between the desert ecosystem and the atmosphere during 2005 and 2006. By combining measurements of atmospheric carbon dioxide and vertical wind speed, they quantified the net carbon dioxide consumed by the ecosystem's biomass, from shrubs to microscopic organisms living in the soil. The annual removal of the greenhouse gas from the atmosphere was upwards of 100 grams of carbon per square metre, on a par with some temperate forests, with the majority being consumed during spring months.

As this amount of carbon dioxide is not being stored in desert plants alone, however, the authors suggest that a significant portion could be stored in the biological crusts, such as blue-green algae, lichens and mosses, that cover most desert soils.