Plankton disturbance at Suape estuarine area -Pernambuco - Brazil after a port complex implantation

The plankton structure was investigated at the estuary of the River Ipojuca after 10 years implantation of a Port Complex. Plankton was sampled in one fixed station. Concurrent hydrological, climatological and chlorophyll a d ata were taken. The course of the river alteration resulted into an estuary that tends to evolves from a classical towards a coastal lagoon type. Chlo rophyll a presented low values for an estuarine mangrove area. Plankton hig h diversity (> 3.0 bits.ind(-1)) can be explained by the spatial heterogene ity, although a general biodiversity decrease was registered after port imp lantation. Phytoplankton presented 98 taxa outranking diatoms (72 species). Zooplankton presented 63 taxa outranking rotifers (29 species) and copepod s (21 species). Less than 5% of these taxa were very frequent. Irregular fl uctuations in plankton densities were observed with a sharp abundance decre ase after port implantation. The community was dominated by marine eurihali ne species with a high proportion of littoral taxa. Meroplanktonic larval r ecruitment was reduced by landing and dredging. The anthropic impacts affec ted the system balance.