A high throughput array microhabitat platform reveals how light and nitrogen colimit the growth of algal cells

Resource availability dictates how fast and how much microbial populations grow. Quantifying the relationship between microbial growth and resource concentrations makes it possible to promote, inhibit, and predict microbial activity. Microbes require many resources, including macronutrients (e.g., carbon and nitrogen), micronutrients (e.g., metals), and complex nutrients like vitamins and amino acids. When multiple resources are scarce, as frequently occurs in nature, microbes may experience resource colimitation in which more than one resource simultaneously limits growth. Despite growing evidence for colimitation, the data are difficult to interpret and compare due to a lack of quantitative measures of colimitation and systematic tests of resource conditions. We hypothesize that microbes experience a continuum of nutrient limitation states and that nutrient colimitation is common in the laboratory and in nature. To address this, we develop a quantitative theory of resource colimitation that captures the range of possible limitation states and describes how they can change dynamically with resource conditions. We apply this approach to clonal populations of Escherichia coli to show that colimitation occurs in common laboratory conditions. We also show that growth rate and growth yield are colimited differently, reflecting the different underlying biology of these traits. Finally, we analyze environmental data to provide intuition for the continuum of limitation and colimitation conditions in nature. Altogether our results provide a quantitative framework for understanding and quantifying colimitation of microbes in biogeochemical, biotechnology, and human health contexts.

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Nutrient colimitation is a quantitative, dynamic property of microbial populations

Held,

Krishna,

Crippa

et al. 2023

Preprint

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Nutrient availability dictates how fast and how much microbial populations grow. Quantifying the relationship between microbial growth and nutrient concentrations makes it possible to promote, inhibit, and predict microbial activity. Microbes require many different resources, including elemental nutrients such as carbon, nitrogen, and the trace metals, as well as complex nutrients like vitamins and amino acids. In nature, many of these nutrients are scarce and their abundances co-vary. This presents the possibility of nutrient colimitation, when more than one resource limits growth simultaneously. Despite growing evidence of possible colimitation in nature, the data is often difficult to interpret and compare due to lack of quantitative definitions for limitation and colimitation. Here we introduce a set of metrics that quantify multiple nutrient limitation in microbial growth. We introduce the limitation coefficient to quantify limitation by individual resources and a colimitation index for measuring the effective number of limiting resources. These quantities demonstrate that limitation conditions are not binary or static, but rather exist on a continuum and can change over time as resource conditions change. These definitions facilitate quantitative comparisons between laboratory experiments and nutrient conditions in nature. Furthermore, they allow us to illustrate how limitation of microbial growth rate and biomass yield are related but distinct notions. To demonstrate these concepts, we measure growth ofEscherichia coliunder laboratory conditions and demonstrate that colimitation occurs in clonal populations and is readily accessible in laboratory conditions. Finally, we apply our framework to environmental data to provide intuition for what limitation conditions might exist in nature.

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A high throughput array microhabitat platform reveals how light and nitrogen colimit the growth of algal cells

Cited by 3 publications

References 84 publications

Are microbes colimited by multiple resources?

Are microbes colimited by multiple resources?

Nutrient colimitation is a quantitative, dynamic property of microbial populations

Nutrient colimitation is a quantitative, dynamic property of microbial populations

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