In this way, the high levels of nutrients, mainly at sites along and downstream of the city of Sao Mateus (as evidenced by the PCA) possibly have favored Bacillariophyceae and Cyanophyceae
No rio Guairaca, a densidade das classes foi Bacillariophyceae (93%), Zygnemaphyceae (2,2%), Cyanophyceae
(2%) e Chlorophyceae (2%).
Among dominant and abundant organisms occurred the predominance of filamentous algae; 83% of Cyanophyceae
and 54% of Zygnemaphyceae presented this morphology (Table 3).
No lago das Rosas, nos meses de junho e outubro, Cyanophyceae
foi a classe predominante, caracterizado por Synechocystis aquatilis, e no mes de agosto a classe Chlorophyceae foi a mais representativa, caracterizado por Desmodesmus communis (Figura 5C).
Em ambos os ambientes, as classes com maior densidade de algas cm todo período amostral, foram Cyanophyceae
e Bacillariophyceae (Figura 6).
In the phytoplankton, the dominant small Cyanophyceae
Regarding the frequency of occurrence of taxa (Table 2), the phytoplankton consisted of 30 common taxa (10 Cyanophyceae
, 05 Chlorophyceae, 04 Bacillariophyceae and 09 Zygnematophyceae, 01 Chrysophyceae and 01 Dinophyceae); 11 frequent taxa (05 Cyanophyceae
, 03 Bacillariophyceae, 02 Euglenophyceae and 01 Zygnematophyceae); 60 rare taxa (15 Chlorophyceae, 15 Zygnematophyceae, 13 Cyanophyceae
, 09 Bacillariophyceae, 03 Chrysophyceae, 02 Euglenophyceae, 02 Xantophyceae and 01 Cryptophyceae) and 08 constant taxa (02 Cyanophyceae
, 04 Chlorophyceae and 02 Bacillariophyceae), as indicated in the data presented in Figure 3 and Table 2.
In the next reservoir, Capivara, the most eutrophic in the series and with relatively high water retention time (130 ~ 150 days), Cyanophyceae
Ceratium's genera is normally found in waters rich in nutrients, especially phosphate and nitrate and usually in association with Cyanophyceae
(Lund et al.
, Cylindrospermopsis, Ecol, Portugal).
Over several decades, numerous papers have warned about the trophic status of the reservoirs in Rio Tercero basin, where algal blooms are very frequent, mainly Cyanophyceae
and Dinophyceae (Bonetto et al, 1976.
The phytoplankton community of the Armando Ribeiro Goncalves Reservoir, the Pataxo Channel and after the treatment plant, was represented by the following taxonomic groups: Cyanophyceae
, Chlorophyceae, Euglonophyceae and Bacillariophyceae, neverthless the group Cyanophyceae
figured as the most representative group in the three sampling stations (Figure 2) during January and June and in November of 2006.