Strong sesquiterpene emissions from Amazonian soils

Area of Science:

• Atmospheric Chemistry
• Microbiology
• Ecology

Background:

• The Amazon rainforest is a major global source of volatile isoprenoids.
• Canopy emissions are traditionally assumed to be the primary source influencing atmospheric chemistry.
• Recent data suggests additional, unidentified volatile sources exist.

Purpose of the Study:

• To identify and quantify previously unreported volatile organic compound sources in the Amazon.
• To investigate the role of soil microorganisms in atmospheric volatile emissions.
• To develop a model for predicting soil-atmosphere sesquiterpene fluxes.

Main Methods:

• Laboratory analysis of soil samples to determine sesquiterpene emission rates.
• Investigating the influence of soil moisture, oxygen, and microbial activity (rRNA abundance) on emissions.
• Developing a predictive model for soil-atmosphere sesquiterpene fluxes.

Main Results:

• Soil microorganisms are a significant source of reactive sesquiterpenes (SQTs).
• SQT emissions from Terra Firme soil during the dry season were comparable to global canopy emission models.
• Emission rates were correlated with soil moisture, oxygen levels, and microbial transcript abundance.

Conclusions:

• Soil microorganisms represent a major, previously unaccounted source of atmospheric sesquiterpenes.
• This discovery establishes a critical link between soil microbial communities and atmospheric volatile organic compound dynamics.
• Understanding these soil-based emissions is crucial for accurate atmospheric chemistry modeling.