Biofilms are increasingly being recognised as important contributors to both ecological food webs and biogeochemical processes within streams, due to being important sites of microbial diversity, nutrient cycling and biosynthesis. The microbial community composition within biofilms is likely a product of how stream water chemistry is influenced by hydrological processes, importing nutrients such as allochthonous organic matter (OM) from the surrounding landscape, and how microbes themselves influence the chemical environment of streams. Peatlands can be an important source of dissolved OM (DOM) due to natural processes that allow them to store large amounts of OM, that can later be released into streams. Climate change models have predicted that many landscapes will experience shifts in both weather patterns and the intensity of weather events, which will likely impact the concentration and composition of OM and DOM entering stream systems, in turn influencing the composition of stream biofilms.
Little is known about how microbial communities within biofilms respond to sudden intense changes of DOM within stream systems. This study aimed to determine how alpine peatland associated stream biofilm composition changed as a consequence of a storm event. Biofilm samples were collected before and after two storm events and metagenomic techniques were used to determine the composition of the biofilms. Statistical analyses, such as PERMANOVA, nMDS and SIMPER were carried out to determine if any change in biofilm community composition in response to storm driven changes in DOM dynamics could be detected. No statistically significant difference in community composition could be determined between storm events, but site was a strong determining factor of community composition. Our findings suggest biofilm communities are resilient to short-term intense changes to stream water chemistry.