Increased temperature enhances microbial-mediated lignin decomposition in river sediment.
Jialing Li1,2, Weimin Sun3, Yingjie Cao1
1State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Stress Biology, School of Environmental Science and Engineering, School of Life Sciences, School of Ecology, Sun Yat-Sen University, Guangzhou, Guangdong, 510275, China.
Microbiome
|April 1, 2025
Summary
Rising temperatures accelerate lignin decomposition in river sediments by boosting microbial activity. This suggests global warming may increase the breakdown of stable organic carbon, impacting the global carbon cycle.
Area of Science:
- Environmental Science
- Microbiology
- Geochemistry
Background:
- Lignin is a key recalcitrant organic carbon in terrestrial and aquatic ecosystems.
- Sedimentary lignin accumulation forms a stable carbon reservoir.
- Rising temperatures may alter microbial decomposition of lignin in sediments, affecting carbon cycling.
Purpose of the Study:
- Investigate temperature effects on microbial lignin decomposition in river sediment.
- Identify lignin-degrading microbes and pathways influenced by temperature.
- Understand the implications for riverine carbon reservoirs and climate feedbacks.
Main Methods:
- Stable isotope probing with 13C-lignin and 13C-vanillin.
- Analysis of CO2 production and respiration.
- 16S rRNA gene sequencing, metagenomics, and metatranscriptomics.
Main Results:
- Elevated temperatures increased CO2 emissions from lignin/vanillin decomposition and enhanced priming effects.
- Bacterial taxa like Burkholderiales, Sphingomonadales, and Pseudomonadales were identified as key lignin decomposers, with increased abundance and activity at higher temperatures.
- Temperature rise boosted activity of lignin degradation pathways (e.g., β-aryl ether) and other carbon cycling genes.
Conclusions:
- Increased temperature accelerates lignin/vanillin decomposition by enhancing microbial activity.
- Global warming may intensify the decomposition of recalcitrant organic carbon in river sediments.
- This process has significant implications for the global carbon cycle.
