Preface. Plenary. 1. New perspectives through brackish water ecology; R.E. Ulanowicz. Ecophysiology. 2. Physiological and proteomic responses in Mytilus edulis exposed to PCBs and PAHs extracted from Baltic Sea sediments; B. Olsson, et al. 3. Modelling of pristine depth limits for macrophyte growth in the southern Baltic Sea; A. Domin, et al. 4. Active carbon uptake in Laminaria digitata and L. saccharina (Phaeophyta) is driven by a proton pump in the plasma membrane; M. Klenell, et al. Trophic interactions. 5. Growth and C:N:P ratios in copepods grazing on N- or Si-limited phytoplankton blooms; L. van Nieuwerburgh, et al. 6. Effects of grazing and excretion by pelagic mysids (mysis spp.) on the size, structure and biomass of the phytoplankton community; E. Lindén, H. Kuosa. 7. Food and habitat choice of the isopod Idotea baltica in the northeastern Baltic Sea; H. Orav-Kotta, J. Kotta. 8. Blue mussels (Mytilus edulis) in the diet of roach (Rutilus rutilus) in outer archipelago areas of the western Gulf of Finland, Baltic Sea; A. Lappalainen, et al. 9. The effects of turbidity and light intensity on the consumption of mysids by juvenile perch (Perca fluviatilis L.); M. Granqvist, J. Mattila. Population structure and dynamics. 10. The growth of pikeperch (Sander lucioperca L.) and perch (Perca fluviatilis L.) under different water temperature and salinity conditions in the Curonian Lagoon and Lithuanian coastal waters of the Baltic Sea; L. Ložys. 11. Effects of temperatureon egg and larval survival of cod (Gadus morhua) and sprat (Sprattus sprattus) in the Baltic Sea - implications for stock development; A. Nissling. Community structure and dynamics. 12. Infuence of dissolved organic matter from terrestrial origin on the changes of dynoflagellate species composition in the Gulf of Riga, Baltic Sea; I. Purina, et al. 13. Temporal and spatial patterns of crustacean zooplankton dynamics in a transitional lagoon ecosystem; Z.R. Gaziūnaitė, A. Razinkovas. 14. Classification and description of phytobenthic communities in the waters of the West-Estonian Archipelago Sea; G. Martin, K. Torn. 15. Phytobenthos and macrozoobenthos of the Slupsk Bank stony reefs, Baltic Sea; E. Andrulewicz, et al. 16. Climatic and hydrological controls over the zoobenthos in a southern Baltic coastal lagoon; T. Radziejewska, M. Chabior. Modelling. 17. Effects of land-rise on the development of a coastal ecosystem of the Baltic Sea and its implications for the long-term fate of 14C discharges; L. Kumblad, U. Kautsky. Invasive species. 18. Distribution, population structure and salinity tolerance of the invasive amphipod Gmelinoides fasciatus (Stebbing) in the Neva estuary (Gulf of Finland, Baltic Sea); N.A. Berezina, V.E. Panov. 19. Establishment of the zebra mussel, Dreissena polymorpha Pallas, in the Neva estuary (Gulf of Finland, Baltic Sea): distribution, population structure and possible impact on local unionid bivalves; M.I. Orlova, V.E. Panov. 20. The round goby (Neogobius melanostomus) in the Gulf of Gdańsk: a species introduction into the Balt