Abstract:
The temporal dynamics of desert soil microbial communities are poorly understood. Given the
implications for ecosystem functioning under a global change scenario, a better understanding of
desert microbial community stability is crucial. Here, we sampled soils in the central Namib Desert
on sixteen different occasions over a one-year period. Using Illumina-based amplicon sequencing of
the 16S rRNA gene, we found that α-diversity (richness) was more variable at a given sampling date
(spatial variability) than over the course of one year (temporal variability). Community composition
remained essentially unchanged across the first 10 months, indicating that spatial sampling might be
more important than temporal sampling when assessing β-diversity patterns in desert soils. However,
a major shift in microbial community composition was found following a single precipitation event. This
shift in composition was associated with a rapid increase in CO2 respiration and productivity, supporting
the view that desert soil microbial communities respond rapidly to re-wetting and that this response
may be the result of both taxon-specific selection and changes in the availability or accessibility of
organic substrates. Recovery to quasi pre-disturbance community composition was achieved within one
month after rainfall.
