Microorganisms mediate multiple phosphorus fractions to respond to the precipitation patterns in arid deserts

Understanding the relationship between microorganisms and phosphorus (P) fractions under varying precipitation is crucial for developing microbial nutrition strategies in response to environmental changes in arid regions. Here we assessed microorganisms, enzyme kinetics, P fraction dynamics, and P desorption kinetics in a two-year field experiment with various precipitations: drought intensification, natural precipitation, and increased precipitation. The findings showed increased precipitation enhanced bacterial diversity while reducing fungal diversity, observed species, and desorption energy site. Drought intensification promoted stress-tolerant species abundance but decreased moisture-sensitive species, inorganic pyrophosphatase activity, and maximum reaction rate. For P fraction changes, bacteria+fungi jointly contributed 49.9%, enzymes 28.8%, and P desorption 21.4%. A key pathway for microorganisms mediating P fractions in response to precipitation involved enhancing enzyme kinetics, promoting P fraction concentration, facilitating P desorption, and increasing desorbed P, which was then utilized by microorganisms (primarily bacteria). This study provides insight into microbial nutrition strategies in changing ecosystems. Increased precipitation enhanced bacterial diversity but reduced fungal diversity, while drought intensification increased stress-tolerant species but decreased moisture-sensitive species, according to a two-year field experiment with different precipitation treatments in Xiaohongshan, China.