Biofilm disturbance and tracer particle experiment from Mill Creek in Cleveland, OH

Clay tiles and tracer particles were deployed in Mill Creek in Cleveland, OH to investigate how biofilm and streambed materials respond to high flow events. Ten cross-sectional transects were established evenly across a 100-meter reach where cinderblocks with 16 unglazed clay tiles were buried in the streambed near the deepest part of the channel to promote biofilm growth. Particles of sizes corresponding to the 50th, 75th, and 90th percentile of the substrate size classes at each transect were painted and numbered for use as tracer particles. Samples from the tiles were collected after each high-flow event and measured their biomass using chlorophyll a (chla) and ash-free dry mass (AFDM). Movement of tracer particles (yes/no) was recorded to estimate how much of the streambed moved.