phytoplankton was mainly composed of diatoms (mean values ranged from 52% to 74% of total), except at Marghera, where microflagellates prevailed (avg¼52%
of total; Fig. 2). Other classes were found occasionally:
coccolithophorids, typical of marine environments, were
mainly observed at Lido, but always in very small percentages
(max 1%).