Análise nictemeral da comunidade planctônica do reservatório do Passaúna em Curitiba-PR

Abstract

Supply reservoirs are constructions that modify the chemical, physical, and biological attributes of an entire area, potentially causing significant impacts. Therefore, they are the focus of various studies and monitoring efforts, such as water quality monitoring. The planktonic community can be used in this monitoring due to its characteristics and its susceptibility to abrupt changes. In view of this, the objective of this study was to evaluate the changes in the planktonic community over a 24-hour period in the Passaúna Reservoir located in Curitiba/PR, which is responsible for supplying about 22% of the population of the Metropolitan Region of Curitiba. In 2019, a floating photovoltaic power plant was installed near the reservoir's intake point. Thus, this study also seeks to assess whether these panels cause changes in the planktonic community by collecting samples at two points: LR (near the intake point) and PV (center of the floating photovoltaic power plant). Samples were collected over a 24-hour period, at 3-hour intervals, at three depths: surface, 4 meters, and 8 meters. From these samples, 1 ml was taken for counting the individuals present. Abiotic data characterized the environment as stratified at the time of sampling due to a mean temperature difference of 5º C between the bottom and the surface at point LR. At point PV, these data analyses were not conducted to the same depth as point LR, making it impossible to indicate stratification at this point. The most abundant phytoplankton taxa were Pediastrum and Peridinium, present at all times throughout the water column, and the most abundant zooplankton were taxa from the phylum Rotifera, notably Keratella. Due to weather conditions such as strong winds, it was not possible to identify the nocturnal migration phenomenon of zooplankton, but the vertical migration of phytoplankton was observed. It is considered that the intake region has good water quality, mainly due to the low occurrence of cyanobacteria, and that the floating photovoltaic power plant did not interfere with the diurnal migration of the planktonic community.