Soil microbial community on Tibetan plateau

The Qinghai-Tibetan Plateau is experiencing a rapid warming and wetting since the 1950s. However, there was limited information about how the projected climate change will impact on the soil microbial community and their activity in the region. 72 soil samples were collected at 24 different sites along a temperature and precipitation gradient (substituted by aridity index ranging from 0.079 to 0.89) of the Tibetan Plateau. The abundance of bacteria, ammonia-oxidizers (AOA and AOB) and denitrifers (NirK/S and NosZ genes containing communities) as well as N turnover enzyme activities (potential nitrification rate (PNR) and denitrification enzyme activity (DEA)) of the samples were assessed. We found quadratic polynomial relationships between the aridity index (AI) and soil microbial parameters (gene abundance, community structures, microbial diversity, and N turnover enzyme activity) with a threshold at AI= 0.27. Soil microbial parameters were significantly changed (linear increase or decrease) in areas with AI<0.27 (alpine steppes), while most parameters were relatively stable in mesic areas with 0.27