Stream ecosystems are complex systems where a range of process rates can be measured at multiple scales. Organic matter decomposition is a spatially variable process, and a patch dynamics perspective may provide an effective method of understanding variability in stream ecosystem function. Using a cotton-strip assay, decomposition and respiration rates were measured in diverse substrate and flow patches within a 100-meter reach of Breakneck Creek in Kent, Ohio. Cotton strips were placed at three depths in each of twelve sites representing silt to gravel substrate size. Strips were removed after 2-4 weeks and tensile strength and respiration rates were measured. Strips in coarse substrate decomposed faster when placed higher in the water column, but strips in patches of fine substrate decomposed at the same rate regardless of water column placement. These results show that differences in organic matter processing in different patches can be explained by substrate size and flow velocity. By understanding these mechanistic relationships between physical conditions and process rates, we gain a deeper understanding of the relationship between smaller scale environments to entire streams and watersheds.