Adaptive patterns of bacterial communities under increased temperature and precipitation associated with soil displacement

Abstract:

The temperature and precipitation variations caused by global climate change have profoundly impacted soil microbial communities. Understanding the impacts of the variations on the structure and function of microbial communities over time is crucial for predicting and adapting to future climate changes. [Objective] To explore the variations in the diversity, composition, structure, and succession of bacterial communities in mollisol soil in the context of climate change. [Methods] Based on a long-term soil transplantation experiment platform of Hailun, Fengqiu and Yingtan Agroecosystem Field Experiment Stations of the Chinese Academy of Sciences, we translocated the mollisol soil from a cold-temperate region (Hailun) to a warm-temperate region (Fengqiu) and a mid-subtropical region (Yingtan) to simulate the increasing conditions of temperature and precipitation. We collected 63 mollisol soil samples from Hailun, Fengqiu, and Yingtan during 2005–2011. We employed high-throughput sequencing of the 16S rRNA gene to study the diversity, composition, and structure of soil bacterial communities under different temperature and precipitation conditions. With consideration to the soil physicochemical properties, we analyzed the relationship between environmental factors and microbial community characteristics and calculated the species turnover rate. [Results] After six years of transplantation of the mollisol soil from the cold temperate zone to warm temperate and mid-subtropical zones, significant changes occurred in soil physicochemical properties, including decreases in soil organic matter and total nitrogen, along with a noticeable reduction in aboveground biomass. Moreover, the bacterial diversity in the soil decreased, and significant changes occurred in the community composition and structure. The dominant bacteria included Verrucomicrobia, Proteobacteria, Acidobacteria, and Actinobacteria, among which Verrucomicrobia showed increased relative abundance after the soil transplantation to the warmer area Yingtan. Additionally, climatic factors were highly correlated with microbial community characteristics. The nonmetric multidimensional scaling analysis showed that the bacterial community structure evolved with changes in temperature and precipitation and over time, which was related to the increased microbial species turnover rate. The species turnover rates of bacterial communities varied significantly under different temperature and precipitation conditions, following an increasing trend of Hailun (0.030)[Conclusion] A six-year increase in temperature and precipitation significantly reduced the bacterial diversity, altered the bacterial community composition and structure, and accelerated the species turnover.