Soil biochar amendment affects the diversity of nosZ transcripts: Implications for N₂O formation

Area of Science:

• Environmental microbiology
• Soil science
• Biogeochemistry

Background:

• Denitrification processes are significant sources of nitrous oxide (N₂O), a potent greenhouse gas.
• Soil biochar amendment is known to reduce N₂O emissions, but its impact on microbial communities driving these transformations is unclear.

Purpose of the Study:

• To investigate the effect of biochar on the structure and function of microbial communities involved in nitrogen redox transformations, specifically denitrification and N₂O reduction.
• To analyze the community composition of actively denitrifying and N₂O-reducing microbes under biochar amendment.

Main Methods:

• Soil microcosm experiment under denitrifying conditions.
• RNA sampling at different time points.
• Illumina amplicon sequencing of nirK, typical nosZ, and atypical nosZ mRNA transcripts.

Main Results:

• Biochar significantly increased the diversity of nirK and typical nosZ transcripts within 10 days.
• Biochar addition induced taxonomic shifts in the typical nosZ-expressing microbial community.
• Increased transcript production was observed among microbial species specialized in direct N₂O reduction.

Conclusions:

• Biochar amendment enhances microbial N₂O reduction activity, potentially coupling reduced N₂O emissions with increased microbial N₂O reduction.
• Specific groups of typical and atypical N₂O reducers are influenced by biochar.
• Further research across diverse soil-biochar systems is needed to confirm these findings.