Is it possible to evaluate the ecological status of a reservoir using the phytoplankton community?

Abstract

Aim: The present study aims to evaluate the ecological status of the Broa reservoir through the application of the ecological index Evenness E2 on phytoplankton. Methods Phytoplankton samples from surface were obtained during the dry period (June/2015) in 9 points (P1 to P9), along a longitudinal transect in the reservoir. The qualitative analysis was performed using binocular optical microscope, and the quantitative analysis was performed using the sedimentation chamber method and inverted microscope analysis. The Uniformity Index was calculated on density and richness data. The reference values used in this study were set according to the literature covering 5 classifications (High, Good, Moderate, Low and Bad) for the water quality from Evenness E2 index for phytoplankton, being 1 the maximum value. Results The values observed ranged from 0.1142 in P1 to 0.1468 in P3, being both classified as “Bad”, since values were less than0.21. Conclusions The result reinforces the sanitary problem of the reservoir, the occurrence of consecutive algae blooms because the amount of nutrients in the region. A massive occurrence of Cyanobacteria was observed, with emphasis on the species Aphanizomenon gracile, which may be related to the adaptive advantages that this class presents on the community in eutrophic environments. Activities in the basin can contribute effectively to the eutrophication process of the reservoir, such as agriculture, sand mining and livestock. The water quality is compromised due to the dense presence of potentially toxic species, reflects of the eutrophication process, pointing commitments for the multiple uses of the reservoir, as well as human and ecosystem health. These processes could be corroborated by the application of the index and indication of poor water quality.

Functional erosion and trait loss in fish assemblages from Neotropical reservoirs: The man beyond the environment

“…We observed that the human pressure (indexed by the HFI) was the variable with the most significant number of relationships with fish functional traits. In reservoirs with intensified human activities, we may also expect a higher trophic degree (eutrophication; Vicentin et al., 2018) and an increased number of introduced species (Ortega et al., 2015). The eutrophication process emerges because of the intense nutrient input from untreated human sewage such as reactive phosphates and sulphates (Schindler, 1974; Vicentin et al., 2018).…”

Permanent occurrence of Raphidiopsis raciborskii and cyanotoxins in a subtropical reservoir polluted by domestic effluents (Itupararanga reservoir, São Paulo, Brazil)

“…However, Casali et al (2017) identi ed an opposite pattern in the dominance of R. raciborskii with respect to the climate, with high biomass values in the dry period (>1.0 x 10 7 µm 3 mL -1 ) and lower values in the rainy season (~5.0 x 10 6 µm 3 mL -1 ). Other studies have also reported the abundance of R. raciborskii in Brazilian reservoirs in the dry and rainy seasons, in addition to species of the genera Dolichospermum and Aphanizomenon (Figueredo & Giani 2009;Moschini-Carlos et al 2009;Sant'Anna et al 2011;Bittencourt-Oliveira et al 2014;Fonseca et al 2014;Nishimura et al 2014;Machado et al 2016;Santos et al 2018;Vicentin et al 2018;Rodrigues et al 2019).…”

“…This occurred after the reported intoxication of 131 chronic kidney disease patients at a hemodialysis clinic in the city of Caruarú (Pernambuco State, Brazil), due to contamination of the water by microcystins (Carmichael et al 2001). Studies have reported the occurrence of blooms of potentially toxic species in different regions of Brazil, mainly associated with the presence of R. raciborskii and Microcystis spp (Figueredo & Giani 2009;Moschini-Carlos et al 2009;Cunha & Calijuri 2011b;Bittencourt-Oliveira et al 2014;Fonseca et al 2014;Nishimura et al 2014;Machado et al 2016;Casali et al 2017;Santos et al 2018;Vicentin et al 2018;Rodrigues et al 2019). The identi ed cyanotoxins included saxitoxins, microcystins, and cylindrospermopsin (Molica et al 2002;Moschini-Carlos et al 2009;Bittencourt-Oliveira et al 2014;Casali et al 2017;Pedrosa et al 2020).…”

Phytoplankton, Trophic State and Ecological Potential in reservoirs in the State of São Paulo, Brazil

“…These organisms represent an important element of aquatic ecosystems, playing a central role in their structure and functioning. Phytoplankton responds rapidly to any change in the environmental characteristics of an ecosystem, mainly to nutrient concentrations, and has been widely used in water monitoring studies (Vicentin et al, 2018;Batista and Fonseca, 2018;Moschini-Carlos et al, 2017;Tucci et al, 2009).…”