EFFECTS OF ENVIRONMENTAL FACTORS ON SUCCESSION OF MICRO-PHYTOPLANKTON COMMUNITY IN A MARINE SHRIMP POND AND ADJACENT AMAZON ESTUARY

This study aims to evaluate the effects of the environmental factors and Litopenaeus vannamei farm effluents on succession and structure of the micro-phytoplankton community and water quality in the shrimp pond and adjacent estuarine waters along the two intensive shrimp production cycles. The surface water samples for quali-quantitative analyses were monthly collected in five points, in the shrimp pond (3) and the adjacent estuary (2), using a plankton net (64 mu m) and polyethylene containers, during in the rainy season, and in the dry period. The micro-phytoplankton community was composed by 205 taxa. The environments were different in relation to the total abundance, richness and species indicators with the estuary presented the highest values in relation to the shrimp pond. The diatoms were predominant mainly in the estuary, with the higher abundances and the great majority of indicator species, while in the shrimp pond, the number of indicator diatoms was much lower allowing the establishment euglenophytes and cyanophytes as also indicator species. In the shrimp pond the main drivers of micro-phytoplankton community structure were the higher concentrations of ammoniacal nitrogen, nitrite, nitrate and phosphate, mainly in relation to the feed accumulation, while in the estuary, the main driver factor was the seasonality.