An approach towards absolute abundance data from soil communities are direct cell counts obtained through fluorescence microscopy \cite{Bloem1995} or fluorescence activated cell counting \cite{Khalili_2019}. Total counts help to assess the absolute abundance of microbial cells that fall within a certain range of parameters such as cell size and morphology. This also means that cell counting is way easier for bacteria than for fungi or other soil eukaryotes.
Counting of cells may help to circumvent overestimation of bacterial diversity related to extracellular DNA by counting only intact cells (48, 49)⁠. 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 within 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 increased 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 (e.g. total cell numbers, microbial biomass and PLFAs) can help guiding the interpretation of sequencing data but that their additional value is limited at the same time. 
In contrast, the observation and enumeration of target species of interest through marker-based approaches (e.g. FISH: fluorescence in situ hybridization) enable the quantification of absolute abundances of those species identified through sequencing. This practice not only enables soil ecologists to 1) knowing if the change observed in relative abundance indeed translates to changes in the community \cite{Piwosz2020} , but also expands the interpretation of sequencing data to 2) localizing and visualizing species of interest in situ \cite{Martin_2020} and 3) to hypothesizing about ecological causalities behind changing abundances of target species in soil samples (REF).
Applications of FISH to soil samples are rare (e.g. \cite{Ushio_2014}) which may be due to the fact that the technique was mainly used in marine and limnic ecological research and has been considered as challenging in soil mainly due to low activity of soil bacteria (i.e. low copy number of 16S rRNA genes per cell). These limitations have been largely addressed through methodological adaptations to increasing fluorescence \cite{Schmidt_2013,Stoecker2010} and we suggest to include targeted enumeration if the dynamics of certain phylogenetic groups in soil are to be understood on a quantitative basis .