## 4 Results
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Properties of Groups of**}} & \multicolumn{8}{c}{**Sectors**} \\ \cline{2-10}  & \multicolumn{2}{c}{**PFR**} & \multicolumn{2}{c}{**R**} & \multicolumn{2}{c}{**RA**} & \multicolumn{2}{c}{**FR**} \\ \cline{2-10}  & **2007** & **2018** & **2007** & **2018** & **2007** & **2018** & **2007** & **2018** \\ \hline \multicolumn{10}{c}{**Emerging Macrophytes (EM)**} \\ \hline Number of species & 7 & 17 & 4 & 8 & 3 & 5 & 3 & 3 \\ Range: depth (m) & 1.3 & 1.4 & 1.2 & 1.2 & 1.2 & 1.3 & 1.3 & 1.3 \\ Density (ind\(\cdot\)m\({}^{-2}\)) & 48 & 52 & 50 & 53 & 20 & 24 & 30 & 37 \\ Biomass of emerging & 312 & 345.2 & 202.4 & 237 & 84.8 & 96.5 & 79.5 & 107 \\ \multicolumn{10}{c}{Species dominant in biomass} & Ph. aust. & Ph. aust. & Ph. aust. & Ph. aust. & Ph. aust. & Ph. aust. & Ph. aust. & Ph. aust. \\ \hline \multicolumn{10}{c}{**Submerged Macrolytes (SM)**} \\ \hline Number of species & 5 & 7 & 7 & 5 & 7 & 6 & 8 & 9 \\ Range: depth (m) & 6.2 & 6.7 & 5 & 6.1 & 5.3 & 6.5 & 5.2 & 5.5 \\ Biomass of emerging & 67.3 & 108.6 & 99.8 & 298.9 & 216.4 & 270.9 & 208.2 & 214.3 \\ \multicolumn{10}{c}{Species dominant in biomass} & Ch. frag. & Ch. frag. & Myr. & Myr. & Myr. & Myr. & Elod. & Myr. \\ Number of species of the & 0 & 1 + 1 & 7 & 2 & 7 & 2 & 2 & 2 \\ remaining groups (PM+ FM) & 88 & 102.1 & 15 & 39.7 & 2 & 10.85 & 8.5 & 9.03 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: The characteristics of particular groups of macrophytes of the littoral of Lake Piaseczno (EM, emerging macrophytes; SM, submerged macrophytes; FM, floating macrophytes; PM, pleuston macrophytes; Ph. aust., _Phragmites australis_, Ch. frag., _Chara fragilis_, Myr. alter., _Myriophyllum alternifoliaium_, Elod. can., _Elouca canadensis_). Figure 6: Mean values with ranges of biological indicators of the trophic status of waters of the littoral in sectors of the catchment of Lake Piaseczno in the 2015 and 2018 summer seasons: GPP, Gross Primary Production (mg \(\mathrm{C_{ass}\cdot m^{-2}\cdot h^{-1}}\)); CHLa, chlorophyll \(a\) concentration (mg ChL_a_\(\cdot m^{-2}\)); TSI CHLa, Carlson’s Trophic State Index. Chlorophyll \(a\) concentrations (CHLa) showed a somewhat lower variability. In the 2015 summer season, the mean values of the factor varied from 5.55 (R-RA) to 8.61 (PFR) mg ChL_a_\(\cdot\)m\({}^{-2}\), and in 2018 from 5.12 (FR) to 8.29 (PFR) mg ChL_a_\(\cdot\)m\({}^{-2}\). They contributed to the adequate variability of values of the calculated Carlson's Trophic State Index (TSI CHLa): 47.03 (R-RA) and 50.63 (PFR) for the 2015 summer season and 46.55 (FR) and 50.8 (PFR) for the 2018 summer season (compare Figure 6). The values of the analysed physical-chemical properties of littoral waters in the period showed low variability, adopting ranges that are typical of waters with low intensity in the eutrophication process. Reaction (pH) in the 2015 and 2018 summer seasons varied from 7.05 to 7.85, the electrolytic conductivity (EC) from 92.1 to 100.5 \(\upmu\)S\(\cdot\)cm\({}^{-1}\), the oxygen concentration (O\({}_{2}\)) from 8.25 to 9.60 mg O\({}_{2}\)\(\cdot\)dm\({}^{-3}\), and water temperature from 23.0 to 24.6 \({}^{\circ}\)C (compare Figure 7). Due to the intensification of metabolic processes related to the direct contact with the catchment, the lake's littoral is not a competent location for the analysis of the limnological status of the entire lake. The appropriate place for such analyses is the trophogenic zone of the pelagial of Lake Piaseczno, for which the mean values of biological trophic indices in the 2015 and 2018 summer seasons were as follows: GPP: from 9.02 (2018) to 14.6 (2015) mg C\({}_{\text{ass}}\cdot\)m\({}^{-2}\cdot\)h\({}^{-1}\) (translating into: 108.24-175.2 mg C\({}_{\text{ass}}\cdot\)m\({}^{-2}\cdot\)d\({}^{-1}\)); CHLa: from 4.49 (2015) to 4.54 (2018) mg ChL_a_\(\cdot\)m\({}^{-2}\) (which translated into similar values of the calculated indicator); and TSI CHLa: from 45.1 (2018) to 45.22 (2015) (Figure 8).