Experimental warming accelerates positive soil priming in a temperate grassland ecosystem

Area of Science:

• Ecology
• Climate Science
• Microbial Ecology

Background:

• Biosphere feedback mechanisms are critical for predicting global warming impacts.
• Soil priming, the decomposition of soil organic carbon (SOC) stimulated by fresh carbon inputs, is a significant feedback mechanism.
• The effect of climate warming on soil priming remains poorly understood.

Purpose of the Study:

• To investigate the impact of experimental warming on soil priming in a temperate grassland.
• To understand how warming affects soil microbial communities and their functional genes related to carbon decomposition.
• To integrate experimental findings into ecosystem models to reduce parameter uncertainty and simulate future carbon dynamics.

Main Methods:

• Experimental warming was applied to a temperate grassland ecosystem.
• Bacterial communities and their unique active phylotypes were analyzed under warming conditions.
• Functional genes associated with soil carbon decomposition were quantified.
• Lab-derived data were incorporated into an ecosystem model to simulate carbon cycling.

Main Results:

• Experimental warming significantly accelerated soil priming by 12.7%.
• Warming altered bacterial communities, with 38% unique active phylotypes observed.
• Genes essential for soil carbon decomposition were stimulated under warming.
• Ecosystem model simulations showed a 9.1% increase in priming-induced CO2 emissions from 2010 to 2016 due to warming.

Conclusions:

• Climate warming enhances soil priming, leading to increased soil organic carbon decomposition and CO2 release in temperate grasslands.
• Changes in bacterial communities and stimulated functional genes are linked to warming-induced priming effects.
• Soil priming represents a potentially significant positive feedback to climate change, influencing the terrestrial carbon cycle.