PHYTOPLANKTONIC COMMUNITY IN ANTHROPITED AREA IN THE ANIL RIVER ESTUARY, SÃO LUÍS - MA

Abstract

Estuaries, as they are connecting areas between rivers and seas, favor the development of urban agglomerations and, as a result, enable activities with great socioeconomic impact, in addition to supporting intense biological activity, being authentic nurseries and maternity hospitals. To carry out this work, two sampling campaigns were carried out, corresponding to the rainy season – PC (Apr/2022) and the dry season – PE (Sep/2022), in spring tides,
during the ebb tide. Collections took place at two sampling points, located upstream of the river, therefore, with greater limnetic input. The studied area corresponds to the Anil River estuary – ERA, currently the most urbanized estuary on the island of São Luís, MA. The physical-chemical data and nutrients of the seawater and the qualitative analysis of the phytoplankton were evaluated, packaged in bottles and transported to the Laboratory of Plant and Marine Biology (LBVM/UEMA) and kept in a freezer. Then, the phytoplankton species were identified to the lowest possible taxonomic level with the aid of an optical microscope and identification keys. For the relevant results, the reduction in water
transparency and salinity values during the rainy season occurred due to a greater supply of water received by estuaries and high rainfall. For nutrients, ammonium ion showed high concentrations at both sampling points, which may be a result of the continuous release of sewage in the study area. In ERA, 156 phytoplankton taxa were recorded, there
was a predominance of diatoms, which were the group with the largest number of families and species throughout the study, they are considered the most important and common phytoplankton group in coastal and estuarine areas.