Distinct ecological strategies drive divergent assembly: strong deterministic specialization in fungi versus higher stochastic adaptability in archaea in coastal salt marshes

Coastal salt marshes are among the most productive ecosystems on Earth, playing a critical role in “Blue Carbon” sequestration and biogeochemical cycling. However, in this dynamic habitat characterized by strong environmental gradients, the mechanisms by which microorganisms from different domains—Archaea and Fungi—respond to spatiotemporal environmental rhythms to maintain community stability remain poorly understood. This study systematically investigated the community composition, assembly mechanisms, and niche characteristics of archaea and fungi in sediments across a broad latitudinal gradient and seasonal scales along the coast of China. The results revealed distinct and contrasting ecological strategies between these two microbial groups. Fungal communities exhibited high environmental sensitivity. In contrast, archaeal communities demonstrated remarkable habitat resilience. This study highlights the contrasting mechanisms where archaea maintain structural stability through a higher relative proportion of generalists and stochastic resilience, while fungi respond to environmental changes through a more extreme reliance on niche specialization and deterministic turnover, providing a new theoretical framework for understanding the maintenance of multi-domain microbial assemblages in coastal wetlands under global climate change.