Fungicide and warming interact to reduce soil ecosystem functioning

Area of Science:

• Environmental microbiology
• Soil science
• Ecosystem ecology

Background:

• Soil microbial communities are crucial for ecosystem functions like plant growth and bioremediation.
• Intensive agriculture and climate change create multiple environmental stressors in soils.
• Understanding microbial responses to combined stressors is vital for predicting ecosystem impacts.

Purpose of the Study:

• To investigate the synergistic effects of fungicide and warming temperatures on soil microbial communities.
• To assess the impact of combined stressors on microbial respiration, metabolic capacity, and plant growth.
• To determine if warming constrains microbial adaptation to fungicides.

Main Methods:

• Experimental evolution and community phenotyping.
• 16S rRNA gene sequencing for microbial community analysis.
• Fungicide resistance assays and Hordeum vulgare plant experiments.

Main Results:

• Combined fungicide and warming synergistically reduced soil respiration, metabolic capacity, and plant shoot biomass.
• Widespread loss of metabolic activity, particularly for carbohydrates and carboxylic acids, was observed under combined stress.
• Fungicide resistance increased 16-fold in fungicide-only treated soil but was constrained by warming.

Conclusions:

• The number of environmental stressors, not just individual ones, is critical for predicting soil microbial community responses.
• Combined stressors can lead to synergistic negative impacts on soil ecosystem functions.
• Warming temperatures can interfere with microbial adaptation to other environmental challenges like fungicide application.