Abstract
Anthropogenic activities have increased phosphorus (P) inputs to wetland ecosystems, potentially altering nutrient cycling and greenhouse gas dynamics. However, the effects of P enrichment on methane (CH(4)) emissions in alpine wetland systems, particularly on the Qinghai-Tibet Plateau (QTP), remain poorly understood. Here, we conducted a 2-year field experiment with graded P additions-low-P (LP, 5 kg·ha(- 1)·a(- 1)), medium-P (MP, 10 kg·ha(- 1)·a(- 1)), high-P (HP, 15 kg·ha(- 1)·a(- 1))-and a control (CK) to assess CH(4) flux during the growing season (May-October). Using opaque static chambers and gas chromatography, we quantified CH(4) emissions alongside key soil environmental parameters and microbial community structures. Results showed that P addition significantly increased CH(4) emissions from the Gahai wet meadow, with CH₄ fluxes 3.75-5.21 times higher than in the control. P enrichment also significantly elevated soil organic carbon and total phosphorus content (P < 0.05), increased the relative abundance of Chloroflexi, and reduced Bacteroidete-a microbial shift likely driving enhanced CH(4) emissions. These findings suggest that phosphorus enrichment alters nutrient availability and microbial community composition in alpine wetlands, promoting CH(4) release and exacerbating carbon loss and greenhouse effects in these ecosystems.