WATER QUALITY AND PHYTO-ZOOPLANKTONIC BIOINDICTORS IN THE COCÓ RIVER ESTUARY, FORTALEZA/CE

Abstract

With the aim of analyzing water quality and verify the presence of phyto-zooplanktonic bioindicators in the Cocó River estuary, monthly plankton collections were carried out between April/22 and April/23. In situ the parameters of water temperature and transparency, salinity, pH, dissolved oxygen (DO), and phosphate and ammonia contents were obtained. The phyto-zooplankton was collected with a specific net and, in the laboratory, analyzed using a trinocular microscope with an attached camera. The presence of Escherichia coli was also verified. The results showed water with transparency characteristic of mesotrophic water, while the phosphate and ammonia contents were similar to those of eutrophic waters. 13 phytoplankton species were identified, distributed in the Cyanophyceae, Bacillariophyceae and Chlorophyceae Classes. As bioindicator species of eutrophicated waters were identified: Cylindrospermopsis raciborskii, Nitzschia sp., Chroococcus sp., Oscillatoria spp. and Ulothrix sp. Species diversity and richness were low, with significant evenness. As for the zooplankton, 18 species were identified, distributed in the Classes Eurotatoria, Copepoda, Branchiopoda, Tubulinea and Ostracoda. As bioindicator species: Brachionus calyciflorus, Filinia longiseta, Moina sp., Hexarthra sp. and Polyarthra sp. Diversity was medium, richness was low and evenness was significant. Microbiological analyzes showed the presence of E. coli. Overall, the waters of the Cocó River estuary were classified as Class 3 brackish and eutrophic.