Distribution of carbon and nitrogen cycle microbes along permafrost peatland profile in Northeast China

Abstract Microorganisms play critical roles in carbon (C) and nitrogen (N) cycles. However, our understanding of the distribution of C‐ and N‐cycling microbial communities along the permafrost peatland profile was limited. We characterized changes in the abundances of bacteria, fungi, archaea, methanogen, methanotroph, ammonia‐oxidizing bacteria, and denitrifying bacteria along a soil profile in the permafrost peatland of the Great Hing'an Mountains, China. Maximum values of bacteria, fungi, archaea, methanotroph, and nir K ‐ type denitrifying bacteria abundances were found for the 0–40 cm layer and minimum values for the 100–150 cm layer. Bacteria, fungi, archaea, methanotroph, and nir K ‐ type denitrifying bacteria gradually decreased in terms of abundance with increasing soil depths. Methanogen, ammonia‐oxidizing bacteria, and nir S‐type denitrifying bacteria all showed the highest abundances in the 40–80 cm layer. Abundances of bacteria, fungi, archaea, methanogen, methanotroph, and nir K‐type denitrifying bacteria were all significantly negatively correlated with pH and C:N values, but significantly positively correlated with TC, TN, and TP levels. In the context of climate change, microbial distribution characteristics in the active, transition, and frozen layers in permafrost peatlands will change, and then affect C and N cycles. Results in this study highlighted the importance of sampling deeper soil depths in the study of microbial distribution and C/N cycles in peatland ecosystems.