Dominance of cyanobacteria in the composition of phytoplankton in a supply reservoir in the semiarid region of Ceará

• Autor(a) principal: Vieira, Rosimara de Sales
• Data de Publicação: 2020
• Outros Autores: Oliveira, Elaine Cristina Conceição de, Ricarte, Elizângela Maria Ferreira, Rodrigues, Joice Layanne Guimarães, Vieira, Diane Sales, Alencar, Samara Alves de, Teixeira, Raimundo Nonato Pereira, Lacerda, Sírleis Rodrigues
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Research, Society and Development
• Texto Completo: https://rsdjournal.org/index.php/rsd/article/view/9476
• topic: Fitoplancton; Cyanophyceae; Abastecimento público; Qualidade da água.; Phytoplankton; Cyanophyceae; Public supply; Water quality.; Fitoplancton; Cyanophyceae; Abastecimiento público; Calidad del agua.

Among aquatic organisms, microalgae deserve to be highlighted because they respond promptly to changes in water bodies. The present study aimed to understand the structure of the phytoplankton community in the Canoas reservoir, Ceará, Brazil, analyzing its relationship with environmental factors, in different periods (dry and rainy). Samples were collected monthly at three sampling points. The samples for analysis of the physical-chemical were obtained with the aid of a collection bottle of the Van Dorn type of 3.5 liters. For the quantification of phytoplankton, the samples were collected from the subsurface, fixed with lugol, analyzed and counted according to the Utermöhl method, using an inverted ZeissAxiovert microscope. Densities, dominant and abundant species, diversity index and equitability were determined. To test the significance between phytoplankton densities and environmental variables, the Shapiro-Wilk test and Pearson's correlation were used. Cyanophyceae showed the highest densities, especially the species of Cylindrospermopsis raciborskii and Pseudanabaena catenata, in both periods. Among the taxa, only two species were considered dominant and five were abundant. The phytoplankton community revealed a specific diversity considered low and the equitability showed a non-uniform distribution (66.6%), confirming the domain of few species. Some physical-chemical variables influenced the structure of the phytoplankton community, a significant correlation was observed (p <0.05). The higher densities observed for Cyanobacteria alert to possible public health risks, since this reservoir is used for public supply, and monitoring is relevant to prevent and minimize possible disorders that may occur due to the presence of a high concentration of these organisms in the water.