Studies describing microbial diversity have increased remarkably over the last decade. However, hypotheses, theories, and conceptual frameworks explaining the complexity of microbial diversity and community assembly are still lacking.
Microbial dispersion is a key mechanism connecting very distant communities. Biogeographical studies will benefit from including the dispersion of both active and dormant microorganisms as drivers of the biogeographic patterns observed on different spatiotemporal scales.
Improving our knowledge of microbial dispersion vectors and the biology of dormant microorganisms will help us to unveil the processes driving the assembly of microbial communities, as well as the dynamics of the rare biosphere.
Protecting microbial dispersion mechanisms should be included in sustainable environmental management plans if we want to ensure the functioning of the ecosystems being managed.
Despite the recent increase in knowledge concerning microorganisms, the processes determining their global distribution and functioning have not been disentangled. Microbial dormant stages are adapted to endure specific adverse conditions related to their dispersion path, suggesting that dispersion is not entirely a stochastic process. Long-term dormancy enhances microbial dispersion, promoting the ubiquity of microorganisms. The evidence leads us to propose that there is a global, recurrent, and spatially cyclical dispersion of microorganisms that we have called the Microbial Conveyor Belt. These dispersion cycles directly influence the distribution of microorganisms, the global cycling of inorganic and organic matter, and thus the Earth system’s functioning.
