Aquatic Ecosystem Stability Depends on Microbial Biogeography

ABSTRACT Aim Aquatic ecosystem stability is mediated by microbial interactions across multiple processes, but its spatial comparability and distribution patterns are poorly understood. A large‐scale field survey spanning diverse aquatic ecosystems was conducted to characterise spatiotemporal ecosystem functional stability (EFS) at genetic, population and ecosystem levels. The study aimed to (1) elucidate geographical patterns of aquatic ecosystem stability and their driving factors and (2) explore the characteristics of ecosystem stability across biological organisation levels. Location China. Time Period July to August in 2019 and 2021; bimonthly from September 2021 to July 2022. Major Taxa Studied Archaea, bacteria, phytoplankton. Methods A framework was developed within the biodiversity‐ecosystem function paradigm to parameterize functional variability, taxonomic variability and EFS in aquatic ecosystems. The carbon biogeochemical cycle served as a key indicator of ecological functions. At the gene level, targeted variables included carbon‐cycling functional genes and bacterial and archaeal community composition; at the population level, photosynthetic efficiency and phytoplankton community structure were analysed; and at the ecosystem level, δ 13 C signatures and microbial community composition (including phytoplankton, bacteria and archaea) were assessed. These hierarchical variables enabled the characterisation of EFS as well as functional and taxonomic variability from genes to ecosystems. Results The EFS exhibited a clear geographical pattern, which was regulated by a trade‐off between the functional and taxonomic variability of planktonic microbial consortia. Notably, EFS displayed allometric scaling from gene to ecosystem levels, with this hierarchy‐specific evolution potentially endowing EFS with multiple perspectives. Furthermore, within the EFS hierarchy, wetlands exhibited the lowest scaling‐up magnitude compared to other aquatic ecosystems (i.e., rivers, lakes and reservoirs). These quantitative attributes of ecosystem stability imply a current state‐dependent regulatory mechanism for managing ecological resilience in the Earth System. Main Conclusion Aquatic ecosystem stability is hierarchically dependent on microbial biogeography across biological organisation levels.