Bacterioplankton and abiotic variables as indicators of water quality in shrimp ponds of the tropical region (Northeastern, Brazil)

Abstract

This work aimed to determine density of the bacterioplankton in two shrimp ponds in Northeastern Brazil during complete cultivate cycles of the Litopenaeus vannamei shrimp, as well as to evaluate correlated variables that influence the water quality and the dynamics of these ecosystems. The study was carried out in two shrimp ponds: one of them with fresh water, and another with marine water. Chlorophyll-a, total phosphorus, pH, dissolved oxygen, salinity, temperature and transparency were verified. Bacterial densities were determined by fluorescence microscopy. A model of the logarithm of the mean as a linear function of observed covariates was carried out. The result is a generalized linear model with Poisson response and link log. Both ponds, characterized as eutrophic environments, presented high densities of bacterioplankton (0.51 x 10⁸ to 1.72 x 10⁸ org mL^-1), and high concentrations of chlorophyll-a and total phosphorus. The study highlights the importance of the adequate management techniques to maintain the water quality in shrimp ponds and its effluents.