Phosphorus accumulation by seabird nesting changes soil bacterial community and nutrient cycles of a subtropical Island

Comprehensive understanding of how seabird nesting influences island soil ecosystems and the underlying mechanisms remains limited. Here, the response of soil bacterial communities in biodiversity and functions to the changing soil properties induced by seabird nesting were investigated based on a case study on a subtropical, unpopulated island of China. Results showed that seabird nesting increased phosphorus input. Soil nitrate nitrogen was also significantly increased, while ammonium nitrogen was decreased. Seabird nesting decreased the alpha diversity of soil bacterial communities and led to a more frangible bacterial co-occurrence network. The relative abundances of Acidobacteriota and Proteobacteria were significantly increased, while that of Chloroflexi was significantly reduced. Soil nutrient cycling might also be weakened via the inhibition of functional genes involved in methane metabolism (pfkA, PFK, etc.), phosphonate transporter (phnC, phnE, etc.), and sulfate reduction (soxA, soxX, etc.). In addition, phosphorus dynamic was identified as the key driver of seabird nesting shifting island soil bacterial communities and nutrient cycles.