No abstract

The aim of this study was to determine the structure of zooplankton in three artificial water reservoirs, the technological function of which is to pre-treat waters from a drainage system of a brown coal open mine by removing inorganic suspension. The background for the zooplankton qualitative and quantitative analyses was the hydrochemical conditions in the individual reservoirs. The greatest zooplankton abundance (N), number of taxa (n), Shannon’s diversity (H'), and species eveness (J') was noted in reservoir Chabielice (Nmean = 1311 ind. L−1, n = 26, H' = 2.09, J' = 0.64) which was dominated by eurytopic Rotifera species (Keratella cochlearis,Keratella tecta,Keratella valga,Polyarthra longiremis,Filinia longiseta). Their abundance was positively correlated with water pH and nutrient concentrations. Reservoir Kamień was characterized by the highest mean values of total suspension (9.6 mg L−1), chlorophyll a (Chl a) content (10.4 μg L−1), and water temperature (20.0 °C). These factors significantly correlated with crustacean biomass. The thermal-oxygenation conditions, low trophic level, and low productivity of the water (Chl a = 5.4 μg L−1) in reservoir Północny determined the overall low zooplankton abundance (Nmean = 153 ind. L−1). Artificial water bodies of opencast mine drainage systems are biologically unstable, but they do have some characteristics of natural ecosystems, and they do take over their functions. Zooplankton is an indicator of their ecological functionality. Knowledge gained about such reservoirs could contribute to decision-making about strategies for water reclamation and how to manage it.

Water from mining drainage is turbid because of suspensions. We tested the hypothesis that the chemical composition as well as shape and size of particles in suspensions of natural origin affect the density and functional diversity of zooplankton. The suspensions were analyzed with atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and optical microscopy. Elements found in the beidellite clays were also identified in the mineral structure of the particles. As the size of the microparticles decreased, the weight proportions of phosphorus, sulfur, and chlorine increased in the suspensions. These conditions facilitated the biomass growth of large and small microphages and raptorials. As the size of the nanoparticles decreased, the shares of silicon, aluminum, iron, and magnesium increased. These conditions inhibited raptorials the most. Ecosystem functionality was the highest with intermediate suspension parameters, which were at the lower range of the microphase and the upper range of the nanophase. The functional traits of zooplankton demonstrate their potential for use as sensitive indicators of disruptions in aquatic ecosystems that are linked with the presence of suspensions, and they facilitate gaining an understanding of the causes and scales of the impact of suspensions.

Predation is an exceptionally important interaction observed in the natural environment. It regulates the population size of potential prey and at the same time decreases competitiveness between them. Among predators inhabiting water environments, especially notable predators are water beetles, particularly adults of Dytiscidae. The results presented herein are an attempt to learn the trophic relations between adult Dytiscidae and non-biting midges (Diptera: Chironomidae). The studies were conducted in one-month intervals from April to September 2012–2013. In the diet structure of adult Dytiscidae of two size categories, the genus

Functional traits can be used to identify various ecosystem processes that are influenced by natural and anthropogenic factors. We tested the hypothesis that the species composition and functional feeding traits of zooplankton are influenced by environmental gradients, such as depth, trophic status, and ion content. This hypothesis was tested in three lignite strip mine lakes in Central Poland. Two shallow, polymictic lakes were reclaimed (1994 and 2008), and the third deep, stratified lake has been reclaimed during the flooding process, since 2011. Samples were collected monthly in 2016 and 2017. The functional responses of zooplankton communities to environmental variables were tested through redundancy analyses. Both eutrophy and oligotrophy contributed to the taxonomic heterogeneity and functional homogeneity of zooplankton. In eutrophic condition small microphagous rotifers and small-sized crustaceans dominated, while oligotrophy and high ion concentrations favored dominance of large microphagous and stationary/suspended feeders. In turn, the depth gradient of a newly emerging, stratified lake resulted in taxonomic and functional heterogeneity of zooplankton. Our results complement existing knowledge about zooplankton in post-industrial areas, and also provide new information on the mechanisms of formation and functioning of mine pit lake ecosystems.