Biodiversity, community structure and function of biofilms in stream ecosystems

Abstract

Multi-species, surface-attached biofilms often dominate microbial life in streams and rivers, where they contribute substantially to biogeochemical processes. The microbial diversity of natural biofilms is huge, and may have important implications for the functioning of aquatic environments and the ecosystem services they provide. Yet the causes and consequences of biofilm biodiversity remain insufficiently understood. This review aims to give an overview of current knowledge on the distribution of stream biofilm biodiversity, the mechanisms generating biodiversity patterns and the relationship between biofilm biodiversity and ecosystem functioning.

Keywords: Biofilm; Microbial diversity; Microbial ecology; Stream ecosystems.

Figure 1

Schematic overview of the interplay of regional and local processes shaping biofilm diversity and community composition patterns. At the regional scale, hydrologic flow paths determine stream biogeochemistry and the metacommunity collected and transported by the streamwater. At the local scale, streambed topography and hydrodynamic conditions control turbulent transport of microbial cells and substrates to the surface, thereby affecting both dispersal and local environmental conditions. Biotic interactions like competition or protozoan grazing, for instance, further modify biofilm community composition and diversity.