The effect of substratum roughness and river flow rate on the development of a freshwater biofilm community

Abstract

This study assessed the effects of substratum roughness, using two grades of silicon carbide sandpaper coupons, and river flow rate on the colonisation dynamics of bacteria, hetero‐trophic flagellates and algae over a 16 week incubation period in the River Conder, UK. In the short‐term i.e. up to 2 weeks, a combination of substratum roughness and high river flow significantly increased bacterial biomass on the coupons, but did not affect any of the numbers cm‐2 of other organisms. In the long‐term i.e. up to 16 weeks, neither parameter appeared to affect the development and maintenance of the mature biofilms. Evidence of a diverse protozoan community within the biofilms was recorded, thereby highlighting the need to consider the effect of these primary consumers on biofilm dynamics in future studies.