Sensitivity of soil nitrifying and denitrifying microorganisms to nitrogen deposition on the Qinghai–Tibetan plateau

Abstract

Purpose Nitrogen deposition at rate not more than 50 kg ha−1 year−1 is generally considered to stimulate soil nitrifying and denitrifying microorganisms via increases in soil nitrogen content. However, this phenomenon in alpine ecosystems remains largely untested. Methods We conducted an 8-year nitrogen deposition experiment on the Qinghai–Tibetan Plateau, with four nitrogen deposition rates of 10 (atmospheric deposition), 20, 30, and 50 kg ha−1 year−1. Results The abundances of two nitrifying genes and four denitrifying genes and the N2O emission rate initially increased and subsequently decreased as the nitrogen deposition rate increased. The observed decrease in these indices at the rate of 50 kg ha−1 year−1 was caused by the toxicity of excessive NH4+. Conclusions Our study demonstrates the vulnerability of alpine microorganisms under global changes.

Composition and distribution of bacterial communities and potential radiation-resistant bacteria at different elevations in the eastern Pamirs

“…To date, prior studies on microorganisms in plateau regions have focused on the Tibetan, Loess, and Mongolian Plateaus. These studies have involved variations in soil enzyme activities and microbial communities along elevation gradients ( Fan et al, 2021 ), reflections of functional microorganisms in soil to natural factors such as nitrogen deposition and precipitation ( Xu et al, 2021 ; Li et al, 2023 ), or different responses of soil microorganisms from different plant communities to changes in environmental stresses ( Xu et al, 2023 ). Relatively few studies have been conducted on the distribution of bacterial communities in East Pamir.…”