Contribution of zooplankton as a biological element in the assessment of reservoir water quality

Abstract

Contribution of zooplankton as a biological element in the assessment of reservoir water qualityEuropean water policies aim to achieve a good ecological status in all water bodies. The Water Framework Directive (WFD) defined a group of biological elements to assess water quality. In reservoirs and lakes, phytoplankton is the only biological element used for water quality evaluation. However, zooplankton is an important link in the trophic web, since it is able to control the phytoplankton community and was already described as a good bioindicator, with high sensitivity to different environmental stresses. The main goal of this work is to demonstrate the ability of zooplankton communities to be used in the evaluation of water quality in reservoirs. A group of four reservoirs in the north of Portugal (Paradela, Alto Cávado, Alto Rabagão, and Venda Nova) were sampled every three months, during one year, to assess the water quality. Physical and chemical parameters, as well as phytoplankton communities, were studied according to the metrics proposed by the WFD for this typology of water bodies. Additionally, zooplankton communities were also sampled in each reservoir, to understand if their seasonal dynamics are influenced by alterations of the water quality in the reservoirs. Results show that the reservoirs present a good ecological potential, according to WFD reference values for physical and chemical parameters and phytoplankton communities, with occasional drops to moderate ecological potential due to variations in the dissolved O 2 and total phosphorus values. The results observed in the dynamics of zooplankton communities show that this biological element is sensitive to changes in the reservoirs and provides a more detailed image of the state of the ecosystem. Zooplankton communities responded to alterations in the water level in the reservoir, to shifts in the trophic status and in the water quality, both at the taxonomic level and on a functional perspective. Therefore, the metrics proposed by WFD to evaluate water quality in reservoirs seem to be insufficient to understand all the alterations that occur in these aquatic ecosystems.

A review on plankton as a bioindicator: A promising tool for monitoring water quality

“…Zooplankton are an important part of aquatic ecosystems as they connect different trophic levels and regulate the flow of energy between different trophic levels (Abrantes et al, 2006; Jensen et al, 2013). Zooplankton provides clear information about the changes in the structure of the ecosystem as compared with phytoplankton (Almeida et al, 2020). Zooplankton species are present in different environmental conditions, and they indicate different environmental conditions (Table 4).…”

Congruence of water column, contemporary and pre‐industrial sediment cladoceran assemblages in 85 Canadian lakes of contrasting human impact levels

“…The most common approach in lake monitoring has been to measure environmental variables and to sample living communities from the water column, to assess current biodiversity responses to stressors. Water column zooplankton structure has thus been incorporated into many water quality monitoring programmes around the globe (e.g., Sodré et al, 2020;Paquette et al, 2021, but see Jeppesen et al, 2011Almeida et al, 2020).…”

“…The most common approach in lake monitoring has been to measure environmental variables and to sample living communities from the water column, to assess current biodiversity responses to stressors. Water column zooplankton structure has thus been incorporated into many water quality monitoring programmes around the globe (e.g., Sodré et al., 2020; Paquette et al., 2021, but see Jeppesen et al., 2011; Almeida et al., 2020). Increasingly, paleolimnological approaches based on the study of natural archives preserved in lake sediments, have been used to provide an integrated perspective capturing changes within lakes and their catchments over longer periods (decades to millennia) (Saulnier‐Talbot, 2016).…”

Assessing the Seasonal and Spatial Dynamics of Zooplankton through DNA Metabarcoding in a Temperate Estuary

“…Ultimately, we will improve our understanding of how climate change impacts marine and coastal ecosystems [10][11][12][13][14]. For instance, these communities have been reported to be sensitive to changes in water levels of reservoirs, trophic changes, and water quality, where commonly used WFD metrics were found to be insufficient for comprehensive quality assessments in these locations [15]. Similarly, in several estuarine systems, zooplankton were found to quickly respond to environmental conditions and anthropogenic pressures [16][17][18][19].…”