Seasonal analysis of microbial metatranscriptomes at the Radiales station E2-Gijón/Xixón

The temporal dynamics in expression patterns of microbial species and gene suites remains largely unexplored, particularly at relatively long time-scales such as during seasonal cycles. We analysed eight metatranscriptomes isolated from coastal waters over two consecutive years with the aim of analysing the seasonal reocurrency in gene expression of active microbial players and a selection of key functional genes. The contribution of the 100 top-expressed taxa to the metatranscriptomes was highly correlated in summer and autumn, but only weakly in spring. Seasonal differences were found in the expression of several functional marker genes, such as pufM, coxL, rbcL or phosphate and BCCT transporters. Different broad taxonomic bacterial groups dominated the expression of these genes, as evidence of functional partinioning of these taxa. In summary, we found temporal reocurrency in the expression of marker genes of globally relevant microbial processes, as potential indicators of seasonal variations in their related biogeochemical rates.