## 3 Results
### Response at Population Level  
Among the dominant species present in the initial communities and present in all variants of the experiments, mainly diatoms were observed. The most abundant species were _Bacillusaria pasillifera, Diatoma moilliormis, Diatoma vulgaris, Navicula perminuta, Tabularia fasciculata_ (Bacillusariophyceae), and _Melosira nummuloides_ (Coscinodiscophyaceae), among others. Among Cyanobacteria (formerly Cyanobacteria), the most abundant taxa were _Spirulina sp._ and _Merismopedia_ sp. Regardless of the degree of dominance in the initial community, individual taxa showed different types of response to the presence of the tested substance. Three types of response were identified: an increase in abundance, which was interpreted as growth stimulation; no change in abundance, interpreted as no response ('indifferent' taxa); and a decrease in abundance, interpreted as growth inhibition. An example of a species that was stimulated by all the substances tested was _Navicula perminuta_ (Figure 3A). This species showed an increase in cell number, by approximately 50% relative to the control, under the influence of copper (II) chloride, an eightfold increase in abundance in the presence of glyphosate, as well as a tenfold increase in abundance in the presence of ionic liquid [BMI]Cl on the seventh day of testing. An unusually large, up to fourfold, increase in abundance under the influence of copper chloride was also observed in _Granmatoripora marina_ (Bacillusariophyceae) (Figure 3B) on the third day, and, in the case of glyphosate and ionic liquid (1.75\(\cdot\)10\({}^{-2}\) g\(\cdot\)dm\({}^{-3}\)), a twofold increase on the seventh day of testing. Some taxa were stimulated by the presence of chemicals only during the initial phase of testing. For example, the number of _Adnanthes adnata_ (formerly _Adnanthes brevipes_) (Bacillusariophyceae) cells in the presence of copper (II) chloride was 135% of the abundance in the control sample on the third day, but only 64% on the seventh day (Figure 3C). Other taxa responded differently depending on the substance  
Figure 2: Average abundance of taxonomic groups in communities during tests. Designations used: the first part of the caption encodes the concentration, e.g., C–control solution, 2\(\cdot\)10\({}^{-3}\)–CuCl\({}_{2}\) concentration; the second part encodes the day of the test—e.g., \(3\) is the third day, \(7\) is the seventh day. Statistically significant differences were marked with * symbol. and/or concentration. For example, glyphosate stimulated the cells of representatives of cyanobacteria to increase in abundance very intensively. Cell abundance of _Spirulina_ sp. increased by 17.5 times that of the control on the last day (Figure 3D), and abundance of _Merismopedia_ sp. increased by about four times for lower concentrations on the third day (Figure 3E). However, the other substances did not affect the change in abundance (neutral response for _Spirulina_ sp. in [BMIM]CI) or had an inhibitory effect (_Spirulina_ sp. and _Merismopedia_ sp. in CuCl\({}_{2}\)). Similarly different responses were observed for the diatom _T. fasciculata_ (Figure 3F). In the case of glyphosate, a stimulation of up to 40% increase in cell numbers relative to the control solution was observed at the highest concentration, no response was observed at intermediate concentrations, and growth inhibition was observed at the lowest concentration. In contrast, copper chloride had no significant effect on changes in abundance for this taxon (\(p<0.05\)). The group of taxa that showed a lack of response to copper (II) chloride also included, for example, _Diatoma moniliformis_ (\(p<0.05\)) (Figure 4A) and _Bacillaria pasillifera_ (\(p<0.05\)) (Figure 5B). However, in the presence of glyphosate and ionic liquid, few taxa showed a lack of response, such as the aforementioned _Spirulina_ sp. which, at 0.85 g\(\cdot\)dm\({}^{-3}\) glyphosate and at both ionic liquid concentrations used, did not change its abundance over the course of the tests.