Seasonal dynamics of active SAR11 ecotypes in the oligotrophic Northwest Mediterranean Sea.

ABSTRACT: A seven-year oceanographic time series in NW Mediterranean surface waters was combined with pyrosequencing of ribosomal RNA (16S rRNA) and ribosomal RNA gene copies (16S rDNA) to examine the environmental controls on SAR11 ecotype dynamics and potential activity. SAR11 diversity exhibited pronounced seasonal cycles remarkably similar to total bacterial diversity. The timing of diversity maxima was similar across narrow and broad phylogenetic clades and strongly associated with deep winter mixing. Diversity minima were associated with periods of stratification that were low in nutrients and phytoplankton biomass and characterised by intense phosphate limitation (turnover time<5 h). We propose a conceptual framework in which physical mixing of the water column periodically resets SAR11 commu

SUBMITTER: Salter I 

PROVIDER: S-EPMC4303628 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature