The phytoplankton of Venice Lagoon. 1. Northern and southern basins (April1988 March 1989)

During research on the phytoplankton in the Lagoon of Venice, monthly sampl ings were carried out from April 1988 to March 198. Samples were collected from four stations in the northern and southern basins of the lagoon during the spring tides (flood and ebb tide). Moreover some environmental paramet ers (transparency, temperature, salinity, dissolved oxygen and pH) were mea sured to point out ecological differences between the stations. Taxonomical identification and quantitative analyses of the planktonic microalgae were carried out. The planktonic microflora was composed by 261 taxa. Diatoms w ere prevalent and only Skeletonema costatum showed sometimes the higher val ues. Microflagellates, which are a heterogeneous group, were also abundant and widespread. Dinophyceae, Cyanophyceae, Euglenophyceae and Chlorophyceae showed low density values; in the southern basin, in January, Dictyocha sp eculum (Dictyochophyceae) registered very high cell density values. On the other hand, in the southern sampling stations, phytoplanktonic concentratio ns were higher than in the northern ones.