Análise nictemeral de fitoplâncton e zooplâncton no reservatório do Passauna em Curitiba-PR

Abstract

Supply reservoirs are targets for studies and monitoring of water quality. The planktonic community is used in this control by the developmental characteristics of the organisms. Thus, this work aimed to recognize changes in the 24-hour period in the population of plankton present in the Passaúna reservoir located in Curitiba/PR, which is responsible for 20% of the integrated supply system in Curitiba. Close to the water catchment, phytoplankton samples were collected in a 24-hour period at a 3- hour interval, at three depths: surface, 3 and 10 meters. From these samples, 1 ml was taken to count the presence of individuals. Abiotic data characterized the environment as stratified at the time of collection, due to a difference in the average temperature of the day between the bottom and the surface of 5ºC. Chlorophyll-a values were higher in the transition region between the surface and the bottom of the site, showing a possible agglomeration of algae in this region. The phytoplankton assemblage was more abundant, the genera Pediastrum, Peridinium and Aulacoseira were more frequent. The predominant zooplankton belong to the Cruataceae subphylum: Copepoda and Cladocera. Through the abundance of organisms, it was possible to identify the phenomenon of nocturnal migration of zooplankton to the surface, with the intention of feeding on algae. Thus, it is possible to consider that the collection point has good water quality, however, one must pay attention to the dominance of the genera found, specifically the Pediastrum, so that there is no imbalance in the ecosystem.