Microbial interactions



Interactions between microbes represent the baseline for the functioning of any ecosystem. We study the mechanisms driving interactions in fresh- and seawaters at different levels, from single prokaryotic cells to microbial communities.
The main ecological interactive factors driving the composition of a microbial community (predation, competition, cooperation) promote the development of complex relations between species and between single bacterial cells within the same species. This is true not only for more simple interactions (e.g. prey-predator) where co-evolution between the predator and its prey often results in a precise and well defined interaction, but also for more complex and obscure interactions, for example communities where different potential competitors and their predators act together for a most efficient degradation of organic matter, or a more efficient genetic transfer.

We focus our researches on the interactions between bacteria and protists in waters, with a specific interest towards co-aggregation of different bacterial strains, or coaggregation between bacteria and cyanobacteria, up to the development of huge co-aggregates where also grazers are involved, and where productivity, efficiency and community composition significantly change from those in the surrounding environment.

Our approach is based on experimental tests and further modelling. We either work with artificial communities built from our a la carte menu of strains, or with single strains, or with natural communities adapted to lab conditions.

The MEG runs a continuous culture facility, but many experiments are also carried out in situ, in batches, or in semi-continuous systems. In the last years we tested a number of ecological factors on microbial communities and on direct strain-to-strain interactions: nutrient limitations and nutrient quality and the relative importance of microplastics in promote interactions within disturbed bacterial communities (with IGB Berlin), antimicrobials (with ETH Zurich, Salerno University, Sun-Yat Sen University in Guangzhou, and Hong-Kong University), predation (with Zurich University and CNR-IRSA Rome), overall community resistance to invasions (with CAS Ceske Budejovice, CNR-ISMAR Venice, and University of Milan).