Global biogeography of desert cyanobacteria

Terrestrial ecosystems that experience prolonged moisture deficit are known as deserts or drylands and these comprise the largest terrestrial biome. As aridity increases vascular plants and metazoans decrease in abundance and the importance of microbial communities increases. A major focus of research has been the hypolithic microbial communities that develop as biofilms on the ventral surfaces of quartz stones, since this substrate is ubiquitous as ‘desert pavement’ in extreme deserts worldwide. Here we hypothesized that hypolithic cyanobacteria display a detectable climate-related difference in diversity, and that this has an impact on overall community assembly and putative community functionality. Here we hypothesized that hypolithic cyanobacteria display a detectable climate-related difference in diversity, and that this has an impact on overall community assembly and putative community functionality. We used a global dataset of hypolithic communities, and combined t-RFLP fingerprinting and high throughput sequencing of 16S rRNA and nifH genes to reveal patterns of taxonomic and putative diazotrophic diversity for hot, cold and polar desert communities.