Frondose macroalgae usually harbors a diverse epifaunal community, whereas sediment among the fronds tends to decrease species richness and diversity. The macroalga Caulerpa racemosa is found in shallow waters and can trap sediment among its stolons. We investigated how the peracarid assemblages from two shores in southeastern Brazil are related to temporal changes in the algal biomass, sediment quantity trapped in C. racemosa patches, and organic matter content from adjacent areas. On both shores, there was no significant difference in the algal biomass through time. Algal clumps from Fortaleza retained at least four times more sediment than from Cigarras, and similar temporal trends of sediment retention were observed at both shores. Overall, 47 species of peracarids were identified. Assemblages from Cigarras were richer and more diverse but remained constant through time. Assemblages from Fortaleza had variation in peracarid species and feeding habits through time, with omnivorous and detritivorous species dominating periods of high loads of sediment. While the presence of sediment seems to negatively affect the abundance and diversity of the epifaunal assemblage, it may favor the presence of detritivores, and tube-building species.