Growth and mortality of coastal microbial taxa

To examine the impacts of bottom-up and top-down controls on marine cyanobacteria microdiversity, we combined a traditional dilution technique with 16S rRNA sequencing and flow cytometry to quantify gross growth rates and mortality rates of natural marine cyanobacteria at the amplicon sequence variant (ASV) level. We hypothesized that, in general, coastal cyanobacteria ASVs would exhibit different gross growth and mortality rates; however, co-occurring ASVs may share similar rate patterns, even if they belong to distinct groups. We also predicted that growth and mortality can help explain the seasonal abundance and dynamics of coastal cyanobacteria at different phylogenetic resolutions. This research will enhance our understanding of microbial community assembly and the mechanisms of co-occurrence for bacteria in the oceans, thereby facilitating the prediction of microbial community responses to ongoing climate change.