## 3 Results and Discussion
In our study, we also observed that the average ALP content was higher in measurement points located at greater depths (points 5 and 9). However, this relationship was not observed for ACP (Figures 4 and 5). These specific points, 5 and 9, located in Lake Jeziory Wielkie, are positioned in an area exposed to greater surface runoff due to the steepest declines occurring within the catchment area, which exceed 31\({}^{\circ}\) (Figure 7). An area with steeper slopes may have a more pronounced impact on pollutant runoff, potentially leading to adverse effects on water quality [34]. This pattern aligns with the findings of [PERSON] et al. [35], who, in their research on alkaline enzyme levels in Lake Sancha, noted that ALP enzyme content was higher in places of pollutant inflow. The parent materials of soils in these catchment areas are glacial till and loamy sand. This explains the higher enzyme contents observed in the case of points 5 and 9 in Lake Jeziory Wielkie, as this type of soil facilitates the penetration of pollutants from agricultural areas with steep slopes. Figure 4: ACP enzyme in bottom sediments of Lake Jeziory Wielkie and Lake Lekno during spring (A) and summer (B). Figure 5: ALP enzyme in bottom sediments of Lake Jeziory Wielkie and Lake Lekno during spring. (A) and summer (B). Figure 6: Analysis of the granulometric composition of soil samples in the lakes. In the case of Lake Lekno, a slightly lower pH was observed in overlying waters during both measurement periods. The average pH in this lake was 7.721. However, concerning org-P in overlying waters in spring, the content was nearly twice as high as during the summer. In summer, the average org-P content was 0.04 mg dm\({}^{-3}\), while in spring, it reached 0.07 mg dm\({}^{-3}\) (Table 2). Upon analyzing the enzymatic activity of phosphatase, it was observed that Lake Lekno exhibited slight differences compared to Lake Jeziory Wielkie. In spring, higher ALP and ACP phosphatase contents were recorded in Lake Lekno than in Lake Jeziory Wielkie. The average ALP content in Lake Lekno was six times higher than in Lake Jeziory Wielkie, amounting to 1567.55 \(\upmu\)g p-nitrofenol g\({}^{-1}\) h\({}^{-1}\). This relationship was also observed for ACP, but the increase in content was slightly lower. The ACP content in Lake Lekno was twice as high as that observed in Lake jeziory Wielkie. Moreover, higher ALP and ACP values were observed in the summer period, reaching three times higher levels than in the spring. Such a high content of ALP and ACP in Lake Lekno can be associated with the specific land use in the catchment area. Forest catchments are characterized by a lower pH, which causes enzymatic processes to differ from those occurring in Lake Jeziory Wielkie (Figures 4 and 5). The highest content of both ALP and ACP enzymes in Lake Lekno was recorded at points 2 and 6, irrespective of the season. These points are situated near water seepage, which are likely to supply the lake with phosphorus compounds that cause such high values of ALP and ACP enzymes. Physicochemical analysis of seepage is important from the point of view of supplying the lake with substances like N and P. The additional water supply can stimulate the growth of phytoplankton and subsequently lead to increased enzymatic activity. In their study, [PERSON] et al. (2016) proved that in lakes with seepage, the concentration of P in lake water samples was positively correlated with the water quality of the seepage. The results of [PERSON]'s WSD test for unequal sample sizes are presented in Table 3. The average depth of bottom sediment sampling was 3.14 m and 2.35 m for Lake Jeziory Wielkie and Lake Lekno, respectively. However, the distance of measurement points from  
Figure 7: Slope in the catchment area of Lake Jeziory Wielkie and Lake Lekno. the shore was, on average, 94.60 m and 70.67 m for Lake Jeziory Wielkie and Lake Lekno, respectively (Table 3). These two variables did not show a statistically significant difference between the analyzed sizes for both lakes.