Local temperature increases reduce soil microbial residues and carbon stocks

Area of Science:

• Soil Science
• Microbial Ecology
• Climate Change Research

Background:

• Soil carbon (C) stocks are crucial for global C cycling.
• Warming temperatures are known to decrease soil C by increasing microbial respiration and decomposition of microbial residue carbon (MRC).
• The specific contribution of MRC to soil organic carbon (SOC) across temperature gradients remains unclear.

Purpose of the Study:

• To investigate the contribution of MRC to SOC along elevation gradients.
• To understand the impact of temperature on MRC and SOC dynamics.
• To elucidate the mechanisms of soil C sequestration under climate change.

Main Methods:

• Studied two elevation gradients in the Tibetan Plateau and Shennongjia Mountain, China.
• Analyzed the relationship between temperature, MRC, and SOC.
• Assessed the influence of environmental factors (soil pH, moisture) and microbial traits.

Main Results:

• Increased local temperatures were negatively correlated with both MRC and SOC.
• Rising temperatures reduced SOC primarily by decreasing MRC.
• Soil pH and moisture were more significant drivers of SOC than microbial traits.

Conclusions:

• Climate warming can reduce C sequestration by accelerating MRC decomposition.
• This process exacerbates the positive feedback loop between rising temperatures and CO2 efflux.
• Understanding these microbial-mediated C processes is vital for predicting soil C dynamics under global climate change.