Phytoplankton groups description from the affluent and effluent in a Litopenaeus vannamei farm with a partial water recirculation system

Abstract

The present work aims to describe the chief phytoplanktonic groups from the affluent and effluent in a marine shrimp (Litopenaeus vannamei) rearing farm localized in the Brazilian Northeast, which has a partial water recirculation system. Samples were collected during the day, at low and high tides. Seven collect points strategically distributed were chosen to characterize the water since its entrance, passing through the interior of the farm, until the exit. All the found results were submitted to ANOVA, followed by the Tukey test with P < 0.05. Chlorophycea was the most abundant group of algae, with an average of 700,000 cell/mL, followed by the diatoms, with 400,000 cell/mL, cyanobacteria, with 230,000 cell/mL, and dinoflagellate, with 8,000 cell/mL, being also observed a growing gradient in the algae concentrations from the most external point (point 1) to the most internal (point 6) one, presenting higher concentrations during the low tide. Results show that the farm effluents increase the concentration of microalgae in the receiving coastal ecosystem.