Eight different diets were prepared for feeding to mussels during each experiment; microcapsules, cellulosic detritus, phytoplankton, benthic microalgae, lab-cultured bacte- ria, bacteria that were collected from Canary Creek just prior to each experiment, a mixed assemblage of lab-cultured bacteria and bacterivorous protists, and a mixed assemblage of bacteria and bacterivorous protists collected from Canary Creek just prior to each experiment.