Convergent Succession of Grassland Archaeal Community under Climate Warming

Understanding the impact of climate warming on the under-ground microbial community in terrestrial ecosystems and the mechanisms driving its long-term succession are critical. Compared with bacteria, however, the archaeal community is frequently overlooked in terrestrial ecosystems. In this study, we examined the the temporal dynamics of soil archaeal communities in a global change experiment in a tall-grass prairie ecosystem from 2009 and 2016. The warming treatment plots have been subjected to continuous +3 oC warming by infrared radiators. Our results showed that experimental warming significantly alter the community structure of archaea. Experimental warming had opposite impacts on the temporal turnovers in archaea and bacteria, i.e., it enhanced the divergent succession of soil bacteria while increased the convergent succession of soil archaea, indicating the potential alleviation of selection pressure from the environment on the soil archaeal community. The predominant group Nitrososphaerales (comprising ≥ 96.5% of the archaeal community), which are potential ammonia oxidizers, showed similar convergent trend as of archaea. Ordination analysis and permutation analysis suggested that stochastic processes played larger roles than deterministic processes in explaining the taxonomic composition of the archaeal community, but less roles in explaining phylogenetic compositions (and the difference between warming and control was significant). Furthermore, the stochastic ratio between the warming and control groups decreased over time, suggesting that the deterministic filtering effect from warming is still an importance factor driving the archaeal community succession. Compared with previous studies, this study demonstrated that although climate warming drives the long-term succession of both the soil archaeal and bacterial community, its relative importance for archaea might be lesser. The restoration strategies for soil archaeal communities, particularly ammonia oxidizers, should focus on managing within community dynamics as a result of assembly rules.