hydrobiologia volume 277 (1994), contents no. 1 J. C. Roos & A. J. H. Pieterse: Light, temperature and flow regimes of the Vaal River at Balkfon- tein, South Africa D. Hongve: Nutrient metabolism (C, N, P, and Si) in the trophogenic zone of a meromictic lake D. Daby: Possible implications of the oceanographic thermal effects in a landsat infrared imagery of Mauritius |. IZaguirre & A. Vinocur: Typology of shallow lakes of the Salado River basin (Argentina), based on phytoplankton communities R. K. Betsill & M. J. van den Avyle: Spatial heterogeneity of reservoir zooplankton: a matter of timing? no. 2 M. Fabiano & R. Danovaro: Composition of organic matter in sediments facing a river estuary (Tyrrhenian Sea): relationships with bacteria and microphytobenthic biomass A. Wong & T. Beebee: Identification of a uniceilular, non-pigmented alga that mediates growth inhibition in anuran tadpoles: a new species of the genus Prototheca (Chlorophyceae: Chlorococcales) M. Serra, M. J. Carmona & M. R. Miracle: Survival analysis of three clones of Brachionus plicatilis (Rotifera) A. Munzinger: The influence of nickel on population dynamics and on some demographic parameters of Daphnia magna R. A. Curry, J. Gehrels, D. L. G. Noakes & R. Swainson: Effects of river flow fluctuations on groundwater discharge through brook trout, Sa/velinus fontinalis, spawning and incubation habitats no. 3 N. Wang & R. Eckmann: Distribution of perch (Perca fluviatilis L.) during their first year of life in Lake Constance L. Wang & J. C. Priscu: Stimulation of aquatic bacterial activity by cyanobacteria L. E. Barnese & C. L. Schelske: Effects of nitrogen, phosphorus and carbon enrichment on planktonic and periphytic algae in a softwater, oligotrophic lake in Florida, USA C. W. Lindau, R. D. DeLaune & J. H. Pardue: Inorganic nitrogen processing and assimilation in a forested wetland S. Meintjes, M. T. Seaman & D. J. Kok: Variations in the morphological characteristics of Triops granarius (Lucas) (Crustacea : Notostraca) in a pan system at Bain’s Vlei, South Africa A. J. Martin, R. M. H. Seaby & J. O. Young: The consequence of a food refuge collapse on a guild of lake-dwelling triclads and leeches Author index