Scaling microbial processes in soil from single cells to the global carbon cycle

One of the major challenges in ecology is to understand how individual organisms operate in the environment to impact ecosystem level processes.

My research addresses this challenge in the context of microbial communities in soil, which play a central role in the global biogeochemical cycling of elements.

My vision to meet this challenge is to create a scalable understanding of microbial processes from single cells to populations to communities to ecosystems to the global scale.

In this seminar, I will present my work that combines theorical, empirical and modelling approaches to understand the ecophysiology of microbes in the soil physico-chemical matrix, their response to land use and climate change and its consequences for soil carbon stabilisation or loss.

To quantitatively link shifting microbial physiology to changes in soil carbon in response to anthropogenic change, we have proposed to characterise the spectrum of microbial physiology as traits.

We hypothesised that individual-level investments and the resulting trade-offs among traits structure populations. This determines the emergent community response to environmental change and consequences for organic matter transformations.

I will present our research on identifying microbial life history strategies based on their traits, and on ways to representing these strategies in models simulating different environmental conditions.

By adapting several theories from macroecology, we define microbial high yield (Y), resource acquisition (A), and stress tolerance (S) strategies. Using multi-omics and stable carbon isotope probing tools, we empirically validated our Y-A-S framework by studying variations in traits across climate change factors (experimentally simulated drought in California grass and shrub ecosystems) and along gradients of resource availability and abiotic conditions arising from land use (across a UK-wide land use intensity gradient and a UK-wide comparison of peatland sites with natural, degraded, and resorted treatments).

These empirical studies demonstrate how trade-offs in key microbial traits can have consequences on soil carbon decomposition and storage.

This emerging mechanistic understanding can be used to design real world interventions for sustainable agriculture, ecosystem drought resilience and peatland restoration.