2020 CAHIERS DE BIOLOGIE MARINE 2020 61(卷), 2(期), (149-158页)
The mesozooplankton biodiversity was studied in the Pacoti estuary, an estuary characterized by a low freshwater flow caused by both semiarid climate conditions and a low river input due to the presence of dams. The mesozooplankton was collected at a fixed-point during ebb and flood tides (spring tide), during the rainy and dry seasons in 2008. Thirty-eight taxa were identified, mainly copepods, such as Acartia (Odontacartia) lilljeborgi and Temora turbinata. No pattern in the distribution of the holoplankton densities was observed between seasons. The low river input promotes the homogeneity in mesozooplankton composition throughout the year. In particular, the high salinity observed most of the year allows the occurrence of marine zooplankton species in the area. When the estuary receives a flush of freshwater from rain or dam's liberation, freshwater zooplankton species may reach downstream regions.