Total cell numbers may also be helpful to guide the interpretation of changes in relative abundances as shown in Figure 3. If the relative abundance of species B was found to decrease between two time points it could well be possible that the total number of cells did not change at all, which could indeed suggest a decrease of species B in the community. If we now assume that the total number of cells increased dramatically between the two time points (Fig. 3X), this could indicate that species B may have increase in number but not as much as other species, which would not suggest a decrease of species B in the community although the relative abundance data could be interpreted as such. These examples highlight that measures of total abundance in a non-targeted manner (cell numbers but also applies to microbial biomass and PLFAs) have a limited additional value to guide the interpretation of sequencing data. In contrast, the targeted enumeration of species of interested, as identified via sequencing, enables to...
Methods such as such as FISH....