The bass would have no available choices from which to choose. However, natural waters are rarely, if ever, uniform in pH. Decaying plants frequently produce acidic compounds that drive down the pH of overlying waters. Thus, bottom waters generally run lower in pH than surface waters. On the other hand, photosynthesis by algae, aquatic plants, and phytoplankton will drive the local pH up. Chemical pollutants can raise or lower pH depending on the specific nature of the pollutant.
Some soils are acidic.
Others are basic. Soil run-offs, therefore, can significantly alter the pH of feeder creeks and those areas where they empty into the main lake or stream. Agricultural fertilizers and nutrients are typically basic. Run-offs from farmlands will often raise the pH of recipient waters. Variances in pH can reach dramatic proportions in the spring due to higher than average rainfalls and snowmelt.