Objectives of this study were to (1) determine whether feeding by the lugworm, Arenicola marina, reduces abundance or alters composition of sedimentary bacterial assemblages, (2) examine recovery of “disturbed” patches of egesta, and (3) test for effects on bacterial abundance, diversity and composition at spatial scales larger than individual fecal mounds. Field comparative studies in Lubec, Maine, were conducted to test for the effects of ingestion, and manipulative experiments were done to assess rates and mechanisms of recolonization of egesta. Bacterial assemblage attributes were followed using epifluorescence microscopy and DGGE analysis of 16S rDNA. Next we examined landscape-scale effects using field addition experiments to manipulate lugworm density (0, 5, and 15 worms m-2). Findings indicate that (1) lugworm feeding qualitatively and quantitatively alters bacterial assemblages, (2) recovery in these biotically disturbed sediments is minimal during a single tidal emersion (∼4.5 h), (3) the small-scale patchiness caused by animal feeding is homogenized by sediment movement following tidal immersion, and (4) landscape-scale effects appear to be small, e.g. with respect to bacterial abundance and “species” richness. One notable landscape-scale effect, however, was a consistent and stable increase in relative abundance of a few specific bacterial phylotypes in high lugworm density plots.