This study investigated the impact of soil pH on denitrification processes, focusing on N₂O emissions and nitrite accumulation. Using metagenomics, transcriptomics, and phenomics, two soils with differing pH (3.8 and 6.8) were analyzed. The acidic soil exhibited delayed N₂O reduction despite *nosZ* transcription, indicating post-transcriptional inhibition of NosZ at low pH. Nitrite accumulation in neutral soil was attributed to high *nar* expression, while low nitrite concentrations in acidic soil were found to be primarily due to biological activity, not abiotic degradation. The study highlights the limitations of using gene and transcript quantification to predict community phenotypes.

Åsa Frostegård, Silas H. W. Vick, Natalie Y. N. Lim, Lars R. Bakken, James P. Shapleigh