Microbial Decomposition of Plant Litter Reveals New Insights into Dissolved Organic Matter Formation

Strategic Insights -

Research at Cornell University has shed new light on the microbial decomposition of plant litter and its impact on dissolved organic matter (DOM) formation. The study, conducted over a period of 150 days in five different ecosystem types, aimed to investigate the relationship between microbial diversity and DOM molecular diversity. The findings suggest that microbial diversity affects DOM molecular diversity, with a positive correlation between DOM functional molecular diversity and microbial community genome size.

Key Takeaways:

  • Microbial decomposition of plant litter decreases the molecular diversity of DOM, but this process is not conserved across ecosystems with differing microbial communities.
  • The study found a positive relationship between DOM functional molecular diversity and microbial community genome size, suggesting that a larger microbial metabolic capacity produces a greater diversity of functionally dissimilar DOM compounds.
  • Ecosystem type explained the most variation in DOM composition, but specific microbial phyla and genera were also correlated with DOM composition across the five ecosystems.
  • The research used 16S rRNA gene sequencing and tandem liquid-chromatography mass spectrometry (LC-MS/MS) to measure microbial richness, microbial diversity, and predicted genome size, as well as DOM molecular diversity.
  • The study received financial supporters from Schmittau-Novak Small Grant through Cornell University, Graduate Research Fellowship Program from the Cornell University Atkinson Center for Sustainability, and USDA National Institute of Food and Agriculture (NIFA) Pre-Doctoral Fellowship.

Statistics:

  • The study used materials sourced from five different ecosystem types.
  • The research was conducted over a period of 150 days.
  • The correlation between DOM functional molecular diversity and microbial community genome size was significant (Pearson's r = 0.61, p = 0.008).
  • Ecosystem type explained 89% of the variation in DOM composition (ADONIS PERMANOVA; R2 = 0.89, p-value = 0.001).
  • DOM molecular richness was most strongly correlated with ecosystem type (F(4,19) = 6.21; p-value = 0.002).
  • DOM functional molecular diversity had a stronger relationship with the predicted genome size of the microbial community (F(4,19) = 21.18; p-value = 0.0002).

Sources:

  • Soil Biology & Biochemistry, "Functional Molecular Diversity of Dissolved Organic Matter Explained By Predicted Genome Size of Soil Microbial Communities," 2025;210.
  • NewsRx, "Reports on Life Science from Cornell University Provide New Insights (Functional Molecular Diversity of Dissolved Organic Matter Explained By Predicted Genome Size of Soil Microbial Communities)," Life Science Weekly, November 4, 2025; p 4783.