Do metals differentiate zooplankton communities in shallow and deep lakes affected by mining tailings? The case of the Fundão dam failure (Brazil)

Deep lakes support higher zooplankton functional diversity than shallow lakes: A case study in lacustrine environments affected by mining tailings (lower Doce River basin, Brazil)

“…Usually, a decrease in zooplankton biomass is related to a reduction in the body size spectrum of the specimens, one of the traits most widely used in the assessment of zooplankton functional diversity. The influence of metals on zooplankton richness in lacustrine environments affected by mining tailings in the LRDV was noticeable, with strong negative effects reported (Santos et al., 2022). Metals can also affect the propagules of zooplankton resting egg banks, as observed by Santos et al.…”

“…The toxic effect of metals in aquatic organisms is associated with the properties of the metal to generate reactive oxygen species (ROS), which present high reactivity and thus impair biomolecules such as proteins, lipids and DNA, modulating critical aspects of zooplankton fitness such as, for example, growth and reproduction (Marques et al, 2022). Evidence of physiological stress on marine zooplankton from the area under influence of the iron tailings was noticeable, with strong negative effects reported (Santos et al, 2022). Metals can also affect the propagules of zooplankton resting egg banks, as observed by Santos et al (2021), who detected a significant reduction in hatching rate and richness under the influence of mining tailings.…”

“…Several metrics have been used to assess the impact of mining tailings on aquatic biota (Isibor et al, 2020;Santos et al, 2022).…”

“…For instance, deep lakes (mean depth > 3.0 m) are commonly thermically and chemically stratified, (Marti & Imberger, 2008; Padisák & Reynolds, 2003), and less resuspension of bottom sediments may favour the retention of metals at the hypolimnion, reducing the deleterious impact of these contaminants on the epilimnion and consequently, on zooplankton. In shallow lakes (mean depth < 3.0 m), sediments are disturbed by wind, and the resuspension of mining tailings from the bottom may drastically alter the turbidity and geochemical characteristics of the water (Santos et al., 2022; Søndergaard et al., 2005; Whitmore et al., 1997), affecting zooplankton functional diversity. Therefore, in shallow lakes metal concentrations remain homogeneously distributed throughout the water column, whereas in deep lakes, owing to stratification, higher concentrations of tailings can be retained at the bottom.…”

“…Several metrics have been used to assess the impact of mining tailings on aquatic biota (Isibor et al., 2020; Santos et al., 2022). However, the functional approach has been gaining substantial prominence (Diniz, Braghin, Pinheiro, Melo, Bonecker, & Melo Junior, 2021; Diniz, Braghin, Pinheiro, Melo, Bonecker, & Melo Júnior, 2021) because, while taxonomic diversity treats species as equally important, functional diversity enables understanding of how species losses may affect ecosystem processes (Hébert et al., 2017; Petchey & Gaston, 2006).…”