Microbes and Soil Animals in Ecosystem models

I am working with soil scientists, ecologists, and ecosystem modelers to improve how we model microbes and soil animals

A figure from a paper in Ecology Letters showing how microbes breakdown organic matter and how they interact with each other and other soil organisms.

Models tracking the flow of carbon and nitrogen through ecosystems have advanced dramatically over the past decade. We are better at predicting ecosystem nutrient cycling, which in turn helps us understand our own effects on carbon and nitrogen cycles (e.g. by the release of nitrogen into ecosystems or CO2 into the atmosphere). I work with these models to add more details about the ecology of microorgnisms and soil animals. My collaborators and I hope to improve our representation of these organisms in models to ensure our models capture their response and its feedbacks to a changing world.

Should we model microbes directly?

Many new models of soil carbon build up and loss include soil microbes explicitly as a pool that can grow and die in response to changes in food supply. These models are better at predicting global trends in soil carbon decomposition than traditional models, which approximate microbial activity by adjusting decomposition rates based on local environmental conditions. Even with these new approaches, it is still difficult to decide how we should include microbes in our models. Do we need to think about their nutrient demands? (I think so!) How about the other soil organisms that feed on them? (I also think so) Some great co-authors and I have written a few papers examining the ways to build microbial ecology into ecosystem and earth system models.