Bacterial diversity on different surfaces in urban freshwater.

Microbial loads in freshwater systems have important implications in biogeochemical cycling in urban environments. Immersed surfaces in freshwaters provide surfaces for bacterial attachment and growth. Microorganisms that adhere initially to these surfaces play a critical role in biofilm formation and sustenance. Currently, there is little understanding on the type of organisms that initially adhere to different surfaces in urban canals. In this study, water from an urban stormwater canal was employed to allow bacteria to attach to different surfaces in a flowcell apparatus and understand the differences and changes in bacterial community structure. Bacterial communities were highly diverse on different surfaces as indicated by Jaccard's indices of 0.14-0.56. Bacteria on aluminium were the most diverse and on Plexiglas the least. Bacterial communities were highly dynamic in the early attachment phase and it changed by 59% between 3 and 6 h on aluminium. Specificity of attachment to surfaces was observed for some bacteria. Judicious use of materials in urban aquatic environment would help mitigate microbial load in urban waters.