Aboveground Productivity Shapes the Active Soil Microbiome Across China

Area of Science:

• Soil microbiology
• Ecology
• Biogeochemistry

Background:

• Soil microbes are crucial for ecosystem functions, but only a small fraction is actively involved.
• Understanding the spatial distribution of the active soil microbiome is vital for predicting ecosystem responses to environmental changes.

Purpose of the Study:

• To investigate the proportion and spatial distribution of the active soil microbiome across China's major biomes.
• To identify the key environmental drivers shaping the active soil microbiome.

Main Methods:

• Standardized soil sampling across 601 sites in China.
• Quantification of the active soil microbiome proportion using 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) staining and flow cytometry.
• Analysis of environmental factors influencing the active soil microbiome.

Main Results:

• On average, less than 2% of soil microbes were active across all sites.
• Forest ecosystems exhibited the highest proportion of active soil microbiomes (>2%), whereas croplands had the lowest (<1%).
• Aboveground productivity, particularly in warmer, wetter tropical regions, was the primary determinant of active soil microbiome variation.

Conclusions:

• Aboveground productivity is a critical factor structuring the active soil microbiome spatially.
• A less productive global environment may lead to significant declines in the active soil microbiome.
• Reductions in the active soil microbiome could impair ecosystem functions and biogeochemical cycles, especially under climate change.