Ecological indexes and phytoplankton structure of urban reservoirs supplied by estuarine waters and under the effects of seasonality (Belém, Pará, Brazil)

Ecological indices are used in the study of phytoplankton because they related to their productivity and can describe stresses caused by anthropogenic impacts on aquatic environment. The aim this was evaluate structure application ecological monitoring water quality public supply reservoirs Belém (Pará). Monthly sampling occurred four stations Bologna Água Preta from January October/2019, determine abiotic biotic factors calculation indices. Turbidity, transparency, precipitation dissolved oxygen were main variables that differentiated reservoirs, evidencing estuarine, seasonal influence species distribution. A total 187 identified with representation diatoms. In January, reservoir presented lower diversity (2.14 ± 0.58 nats.ind-1), equitability (0.57 0.14) higher dominance (0.25 0.19) Trachelomonas volvocina density, contrary June no dominance. Bolonha showed richness (8.3 1.9), (1.2 0.5 nats.ind-1) (0.32 0.12) Gonyostomum sp. (0.55 0.19). sense, considered diverse well distributed environment, while low a species. spatio-temporal variation these good approach environmental quality.