The microorganisms, acting as tiny helpers in the soil, consume leftover plant parts. The food they ingest can be utilized for their growth or released as a gas known as CO2. The research reveals that these helpers release three times more CO2 from the more challenging, woody plants than the sugary parts. This significant finding deepens our understanding of the soil’s role in climate change.
Researchers, in a collaborative effort, found that microbes play a crucial role in soil carbon cycling. This information, discovered through our collective scientific endeavor, can help us better predict how soil carbon impacts climate change. The study, led by Ludmilla Aristilde from Northwestern University, was published in Environmental Science & Technology.
Soil stores about ten times more carbon than the atmosphere, and understanding microbial processes is essential. As temperatures rise, more organic matter becomes available in soil, affecting CO2 emissions from microbial activity.
Ludmilla Aristilde investigates soil carbon dynamics. Her study explores how soil stores and releases carbon. Instead of tracking individual compounds, her team used a mixture to represent natural conditions.
Researchers tagged carbon atoms with isotopes to trace their paths in bacterial metabolism. Different pathways produce varying amounts of carbon dioxide. For instance, sugar carbons from cellulose follow glycolytic and pentose-phosphate pathways, while aromatic carbons from lignin take a different route through the tricarboxylic acid cycle.
Ludmilla Aristilde and her team analyzed microbial metabolism to quantify CO2 production from different plant matter. When microbes consumed a mixture of plant materials, they produced three times more CO2 from lignin-derived carbons than cellulose-derived carbons. Despite simultaneous consumption, the carbon types led to disproportionate CO2 generation due to distinct metabolic pathways.
The study found that when soil bacteria break down different types of organic matter, they release varying amounts of carbon dioxide (CO2). This variability affects how efficiently carbon is used in the ecosystem.
Journal reference:
- Caroll M. Mendonca, Lichun Zhang, et al., Disproportionate Carbon Dioxide Efflux in Bacterial Metabolic Pathways for Different Organic Substrates Leads to Variable Contribution to Carbon-Use Efficiency. Environmental Science & Technology. DOI: 10.1021/acs.est.4c01328.