Shifts in taxonomic and functional structure of bacterial communities during a short-term succession in the High Arctic

Abstract

Primary succession after glacier retreat has been widely studied in plant communities, but bacterial succession is still poorly understood. Here, we investigated the shift in bacterial community structure and soil development along a 145-year old chronosequence in Austre Lovenbreen glacier foreland on Svalbard. Soil bacterial community was investigated via 16S rRNA gene pyrosequencing and potential metabolic functions were estimated using metagenome prediction. Time after glacier retreat played a key role in determining bacterial community structure and soil development during succession. However, environmental filtering (i.e. soil temperature) also accounted for the different but substantial proportion of taxonomic and functional structure of bacterial communities, which was not true for edaphic compositions. Using the functional trait-based approach, we found that average rRNA operon (rrn) copy number decreased over successional time and there is a strong positive relationship between rrn copy number and metabolic functional diversity. It suggests that bacteria rapidly responding to nutrient availability may have potential to adapt well to fluctuating environmental conditions by shifting cellular metabolism and physiology. These results demonstrate an importance role of soil temperature in bacterial community assembly and functioning in deglaciated forefields and trait-based studies have potential to predict the responses of microbial communities to environmental change by linking ecological strategies of soil microbes with ecosystem processes.