With our collaborators Noelle Held, AJ Devaux, and Donat Crippa, former lab members Aswin and Anastasia, and current lab postdoc Rachana, we have just published our paper "Nutrient colimitation is a quantitative, dynamic property of microbial populations" in PNAS (PDF and code are available).
This is the result of our lab's collaboration with Noelle starting over three years ago at ETH Zurich and Eawag, when we first asked how to rigorously define nutrient colimitation and, given such a definition, whether microbial populations in the lab and in nature often experience significant levels of colimitation. In this paper, we develop a theoretical approach to defining nutrient limitation and colimitation in analogy with metabolic control analysis. We apply this approach to systematic laboratory measurements of E. coli population growth over varying glucose and ammonium concentrations to show that colimitation of these nutrients is common under typical laboratory conditions. We then use the framework to analyze data on a variety of species and nutrients from natural environments, which suggests that significant levels of colimitation are common in several natural microbial ecosystems. The approach and results developed in this paper will help us probe the physiological and ecological consequences of microbial colimitation in the future.
