Land-use changes alter the soil microbial community structure and key C, N, and S metabolic functional potentials in the Yuncheng Salt Lake wetland

Abstract

A comprehensive understanding of the microbial communities inhabiting alkaline lake wetlands is critical to maintaining their ecological functions. However, current evidence regarding microbial variations in different habitats of biologically challenging alkaline lake wetlands remains limited. Here, we used high-throughput sequencing technology (16S, ITS, and metagenomic) to analyze the microbial community profile and key metabolic potential of C, N, and S in the surface soil (0–20 cm) of different land-use types (farmland, grassland, and lake embankment) in the Yuncheng Salt Lake wetland. We found significant spatial heterogeneity in wetland soil properties, with salinity gradients and nutrient availability being the main factors driving spatial variation in microbial community structure and metabolic function. Soil bacterial community assembly was primarily driven by environmental heterogeneity selection, whereas stochastic drift processes predominantly governed the structure of fungal communities. The grassland with moderate salinity and rich nutrients exhibited higher co-occurrence network topological complexity and possessed element cycling potential, such as methane degradation. In contrast, the lake embankment under extreme high-salinity stress formed a unique cross-kingdom collaboration pattern distinct from those in farmland and grassland (with an increased proportion of bacterial-fungal interactions) and imposed selective pressure on microbial element metabolism. The diversity of microbial taxa contributing to C, N, and S metabolism was high, which further reflects the critical role of microorganisms in supporting wetland element cycling. Overall, these results provide important insights into understanding microbial adaptive strategies and the functional metabolism of their driving elemental geochemical cycles in alkaline lake wetlands.