Utilização do fitoplâncton como instrumento de avaliação em programas de monitoramento nos ecossistemas aquáticos costeiros. Estudo de caso: Laguna de Araruama/RJ.

Abstract

The severe deterioration of coastal ecosystems caused by human activities has created the need for development and improvement of methods for assessment of environmental quality. The environmental monitoring, basic tool for the management actions of environmental quality (article 6) of the Environment National Policy Law, 6938/81), is used to obtain reference standard situations, that essentially consists of measurements and specific observations generally directed to just a few parameters. The monitoring objectives are: determining whether certain environmental impacts are occurring, the magnitude scale, and also assess whether preventive measures adopted are being effective or not. The purpose of this paper is to highlight phytoplankton usage in the monitoring programs, as an instrument for the impact evaluation on coastal ecosystems. A case study was accomplished in Laguna de Araruama / RJ (22 ° 49 '- 22 ° 57' S and 042 ° 00 '- 042 ° 25' W), one of the largest hypersaline coastal lagoons in the world, and since the 70 s, due to the disorderly occupation of its areas, it has been suffering numerous impacts. When Consórcio Intermunicipal Lagos São João was created in 1999, a lot of positive interventions were performed for the lagoon recovery. One of those benefits was in the Monitoring Program, which uses the phytoplankton as a bioindicator of the quality of its waters, since it can be considered as the main primary producer of pelagic systems, and thus form the the entire trophic web of this system. In 2010 and 2011, the monitoring program revealed that this important ecosystem is eutrophicated and that some toxic diatoms species, such as, Pseudo-nitzschia delicatissima and Pseudo-nitzschia seriata, as well as dinoflagellates, such as, Dinophysis acuminata, and Gambierdiscus toxicus found revealed the danger that the lagoon and the inhabitants that have been feeding on bivalves molluscs and fish are running. Consequentlly, it becomes imperative the constantly monitoring of these species occurrence in fishing area and shellfish capturing, besides urgent steps to wastewater into receiving bodies and the effective implementation of the Projeto Orla by Região dos Lagos government.