Much like any living system soil has its own metabolism driven by a complex network of plants insects worms and especially microorganisms that break down organic matter and cycle nutrients. Soil microbiomes made up of thousands of interacting species play a central role in this process.

Due to this complexity predicting how these microbial communities respond to environmental changes like shifts in temperature moisture pH or nutrients has been a major challenge. However new research from the University of Chicago reveals that a surprisingly simple mathematical model using just two variables can capture these dynamics. The model shows that changes in pH consistently lead soil microbiomes to fall into one of three distinct metabolic states.

Published this week in Nature the study demonstrates how using mathematical models to describe complex systems can simplify our understanding and enable accurate predictions of how soil metabolism responds to environmental changes. This insight could guide efforts to enhance agriculture and restore ecosystems.

The study represents a major effort led by Kiseok Lee a graduate student in Dr. Kuehn’s lab. Lee collected soil samples from 20 natural sites at Cook Agronomy Farm in Pullman Washington an area with wide natural variation in pH but minimal differences in other environmental factors. In the lab he adjusted the pH of each sample in small increments conducting 1,500 microcosm experiments.

Soil pH, which measures the concentration of hydrogen ions influences microbial composition metabolic activity, and soil chemistry. The team specifically investigated how pH changes impact anaerobic nitrate respiration a crucial energy-generating process for microbes that live without oxygen and a key factor in soil health and agricultural productivity.

Understanding how soil microbiomes respond to environmental shifts can inform targeted interventions for instance adjusting pH to reduce nitrate runoff and prevent algal blooms. Knowing the range of possible responses helps us predict how ecosystems will react to future disturbances said Dr. Kuehn.

The study Functional regimes define soil microbiome response to environmental change was published in Nature and supported by several institutions, including NSF NIH and the Chan-Zuckerberg Initiative.

Source: https://www.eurekalert.org/news-releases/1091125