Study reveals how aridity shifts soil food-web energy from plants to microbes, affecting grassland carbon storage

Summary

This study investigates how increasing aridity across global grasslands affects soil food-web energetics and carbon storage. Using a 4,000-km natural aridity gradient spanning temperate and alpine grasslands, researchers found that aridity shifts energy flow from green plant-based channels to brown microbe-based channels in soil food webs. This "browning" effect predicts soil carbon depletion in temperate grasslands, while alpine grasslands show increased soil organic carbon when the green-to-brown energy ratio falls below a certain threshold. The findings reveal a mechanistic link between aridity-driven food-web restructuring and soil carbon sequestration outcomes.