Histograms of the raw data for the single-cell measurements of carbon-13 isotope ratio of bacteria for samples taken at different time points from the algal-bacterial co-culture, for which the algae had been pre-labelled. The blue dotted line indicated the Gaussian distribution fit result when all data points are included and the red line shows the fit when outliers are removed from the analysis. The right plot overlays the Gaussian fit results (with outliers exluded) for all the different time points, which have been normalised such that the total integral of each curve is 1.