Evaluation of genomic sequence-based growth rate methods for synchronized Synechococcus cultures

Standard methods for calculating microbial growth rates through the use of proxies, such as in situ fluorescence, cell cycle, or cell counts, are critical for determining the magnitude of the role bacteria play in marine carbon (C) and nitrogen (N) cycles. Taxon-specific growth rates in mixed assemblages would be useful for attributing biogeochemical processes to individual species and understanding niche differentiation among related clades, such as found in Synechococcus and Prochlorococcus. We tested three novel DNA sequencing-based methods (iRep, bPTR, and GRiD) for evaluating growth of light synchronized Synechococcus cultures under different light intensities and temperatures in order to determine whether they could be used to estimate instantaneous growth rates without the need for incubation experiments in both cultures and natural samples.