Spatial and temporal variability evaluation of periphytc algae and cyanobacteria in backwater areas of Itanhaém river basin, São Paulo south coast

Abstract

Periphyton has great ecological importance in aquatic ecosystems, but identification of the factors that drive their spatial and temporal variability is still a challenge. In addition, the community of periphyton algae and cyanobacteria have important attributes as bioindicators and can be used in the monitoring of the watershed, mainly by ubiquity, sessile mode of life and short life cycle, in addition to integrating the quality of the column of water, as well as the substrate to which it is associated; is generally rich in species, providing a rich system of ecological information for environmental monitoring, thus forming a community spatially compressed, with well defined limits.This project is part of a larger project entitled "Structure and dynamics of communities in coastal streams and rivers of the Atlantic - Itanhaém River basin", under the direction of Professor Dr. Antonio Fernando Monteiro Camargo, established by CNPq (called MCTI / CNPq / FAPs No. 34/2012 - Long Program Ecological Research - PELD).The goal of this research is to increase knowledge about the composition, structure and dynamics of periphytic algae and cyanobacteria, showing information on the geographic distribution and population variability. So goal that guides this study is to check the spatial and temporal heterogeneity of periphytic algae and cyanobacteria on natural substrate of Eichhornia azurea ( Sw.) Kunth in backwater areas of Itanhaém river basin.The Itanhaém river basin is located on the southern coast of the state of São Paulo, this in turn presents rivers with high spatial and temporal variability in their physical and chemical characteristics. The causes of this variability are associated with several factors: such as the origins of each river, the land covered with different aspects of geological, geomorphological and vegetation, in addition to various degrees of anthropogenic influence. Sampling of periphyton community will be held in the areas of backwater eight sampling stations in Itanhaém river basin, being rivers Preto ( 2 ), Castro ( 1 ), Aguapeú ( 2 ) , Mineiros ( 1 ) and Branco (2). The use of these sampling stations is due to the abundant presence of macrophytes in these rivers and the fact that the Preto and Branco rivers are the main affluent of the Itanhaém river these being the most representative river of the basin. The collections will be held quarterly between October 2013 and July 2014, including the different seasonal periods. The natural substrates for material collection petioles periphytic habitats consist of macrophytes in adult stage of the species Eichhornia azurea ( Sw.) Kunth (emerging). The abiotic and biotic data will be obtained simultaneously in the same sampling stations and times. To determine the composition and community structure of periphytic algae, there will be a cut on the petiole submerged for subsequent removal of periphyton. The analysis of the periphyton community will be held under the structural and species composition. The physico-chemical water analysis will be: water temperature, dissolved oxygen, conductivity and pH determined in situ, and the series of nitrogen and phosphorus to will be determined in the laboratory. The chemical composition of aquatic macrophytes used in scraping the material periphytic habitats, will also be determined. For the evaluation of the results will be used biotic and abiotic factors in the multivariate analysis.