expected that the relative rate of a modelled process should be
proportional across depths to the biomass of microbes performing
that process. This interpretative framework, which we call ‘inferred
biomass’, reinterprets implicit biomass models as hypotheses about
microbial community structure. Consistent with these assumptions,
our model largely reproduced the distribution of key organisms
known to perform the corresponding metabolisms in 2013 (Fig. 3)
and 2008 (Supplementary Fig. 7).
The model captures the major patterns in the lake’s chemical
dynamics, but there are discrepancies between the model and observation.
For example, in the final 2013 survey, oxygen concentrations
reach undetectable levels at about 5 m, increase until about 8 m,
then decrease again until reaching the detection limit at 14 m. In
contrast, the model predicts that oxygen concentrations would
decrease monotonically with depth.