Nutrient dominance governs the assembly of microbial communities in mixed nutrient environments

A major open question in microbial community ecology is whether we can predict how the components of a diet collectively determine the taxonomic composition of microbial communities. Motivated by this challenge, we investigate whether communities assembled in pairs of nutrients can be predicted from those assembled in every single nutrient alone. We find that although the null, naturally additive model generally predicts well the family-level community composition, there exist systematic deviations from the additive predictions that reflect generic patterns of nutrient dominance at the family level. Pairs of more-similar nutrients (e.g. two sugars) are on average more additive than pairs of more dissimilar nutrients (one sugar-one organic acid). Furthermore, sugar-acid communities are generally more similar to the sugar than the acid community, which may be explained by family-level asymmetries in nutrient benefits. Overall, our results suggest that regularities in how nutrients interact may help predict community responses to dietary changes.

Automated summary

The study found that while the family-level community composition can generally be predicted using the null, naturally additive model, there are systematic deviations from the additive predictions that reflect generic patterns of nutrient dominance. Pairs of more similar nutrients tend to be more additive than pairs of dissimilar nutrients, and sugar-acid communities are generally more similar to sugar communities than acid communities, possibly due to family-level asymmetries in nutrient benefits. Overall, the study suggests that regularities in how nutrients interact may help predict community responses to dietary changes.