Cross-domain interactions induce community stability to benthic biofilms in proglacial streams

Cross-domain interactions are an integral part of the success of complex biofilms in natural environments. Here, we report on cross-domain interactions in biofilms of streams draining proglacial floodplains in the Swiss Alps. These streams, as a consequence of the retreat of glaciers, are characterized by environmental gradients along longitudinal and lateral chronosequences. We estimate co-occurrence of prokaryotic and eukaryotic communities along these chronosequences and show that key community members have disproportionate effects on the stability of co-occurrence networks. The topology of the networks across the chronosequences was similar, however, the stability of the networks was higher in the more recent sections of the chronosequence. We find that both pro- and eukaryotes are central to the stability of these networks, which fragment upon the removal of both pro- and eukaryotic taxa. These ‘keyplayers’ are not always abundant, suggesting an underlying functional component to their contributions. Overall, our findings elucidate the role of individual taxa to the microbial community stability within glacier-fed streams.