New research from southwest China shows that the type of bedrock beneath a forest can change how soil microbes cycle carbon, nitrogen, phosphorus, and sulfur. Soils formed on limestone carried more functional genes tied to nutrient cycling than soils on dolostone or clasolite. The study used HT-qPCR to profile microbial genes and found limestone soils were especially rich in genes for breaking down organic matter, ammonification, denitrification, phosphorus solubilization, and sulfur oxidation. The authors propose a framework based on nitrogen availability, microbial resource limitation, and reactive minerals. They argue Earth system models should treat carbonate rock types separately instead of grouping all carbonate soils together. That matters for carbon cycle predictions and for any project trying to estimate soil carbon storage or emissions in karst regions.
