Autumn
and winter communities upstream of the reservoirs were dominated
by centric diatoms mostly of the generaCyclotella, Cyclostephanos,
StephanodiscusandThalassiosira, along with pennate diatoms mostly
of the generaFragilaria, NaviculaandSynedra. Chlorophytes (coccal
green algae and single-celled Volvocales) were relevant in spring, and
summer communities were characterized by chlorophytes and dinoflagellates in the upstream section.