The present work represents the first complete study on the mesozooplankton community in a shallow Antarctic coastal area: Potter cove, 25 de Mayo Island, South Shetlands. Results are based on samples obtained during two complete years (2002 and 2003) in Potter Cove and Maxwell Bay, a neighbouring area. This study was conducted within the frame of a comprehensive zooplankton investigation which started in 2002 and is still going on. The major aim of this study is to detect possible changes in the zooplankton community in connection with global change.The role of the main mesozooplankton species in carbon dynamics of Potter Cove was analyzed by calculating the feeding and fecal pellets production rates. By means of trophic markers (fatty acids and C and N stable isotopes) the position of mesozooplankton in Potter CoveŽs trophic web was delimited.Highly variable mesozooplankton abundances were determined through all the temporal and spatial scales analyzed. Fluctuations were associated with the area's hydrography and the variation in sea ice extension. The feeding pressure of some of the resident species (mainly cyclopoid copepods) and other mesozooplankton groups coming from external areas (mainly krill and salps) on the phytoplankton of Potter Cove was higher than the annual estimated primary production . These feeding patterns contribute to the carbon flux, probably representing a carbon source for the benthic fauna. Among the findings of this study, two new zooplankton species (one harpacticoid copepod and one narcomedusa) are described, as well as the first Antarctic record of some decapod larvae.