Microbial community assembly in an evolving ecosystem: Ecological succession and functional properties of soil microbes

The themes of community assembly and ecological succession in soils constitutes rather traditional concepts in ecology, that are as yet not fully appreciated in soil microbiology. This thesis aimed at integrating these themes within microbial ecology by making use of a study system that represents a natural salt marsh landscape formation (i.e. a soil chronosequence). I purposely focused the work carried out throughout this within a two-pronged perspective: (i) fostering the understanding of how different mechanisms drive community assembly and promote spatiotemporal dynamics through ecological succession of the microbial communities along the chronosequence; here I provide both the phylogenetic and functional aspects of the communities, i.e. ‘the ecosystem ecology perspective’; and (ii) explore this natural system for general ecological principles and mechanisms that are potentially applicable across other systems: ‘the microbial ecology perspective’. With respect to the first perspective, the knowledge gained in this thesis provides a better understanding of microbial community variations, connecting these to potential changes in ecosystem functioning. As such, the data are of critical importance for the development of models that aim to better manage salt marsh ecosystems, in particular with respect to monitoring and mitigating anthropogenic and climate change impacts. The second perspective, however, aims at contributing to the continued integration of microbial ecology into the broader field of (theoretical) ecology. I developed and applied concepts from the field of community ecology within microbiology, in an effort to improve our knowledge on the mechanisms that mediate microbial community assembly and successional dynamics.