Biofilms on plastic litter in an urban river: Community composition and activity vary by substrate type

This dataset represent biofilm activity measured on plastic and wood substrates. We incubated three plastics of distinct textures that are buoyant in rivers, low-density polyethylene (rigid; 1.7 mm thick), low-density polyethylene film (flexible; 0.0254 mm thick), and foamed polystyrene (brittle; 6.5 mm thick), as well as wood substrates (untreated oak veneer; 0.6 mm thick) in the Chicago River. Each material was incubated at three sizes (1, 7.5, and 15 cm2). Substrates were incubated at 2-10 cm depths and removed weekly for six weeks. On each substrate, we measured chlorophyll concentration, biofilm biomass, respiration, and flux of nitrogen gas. Chlorophyll, biomass, and N2 flux were similar across substrates, but respiration was greater on wood than plastics. This study provides valuable insights into the effects of substrate on biofilm characteristics, and the ecological impacts of plastic pollution on urban rivers.