Morphology of Peatland Lakes

The morphometric features of 10 small (0.1–2.9 ha) and shallow (4–16 m) peatland lakes, located in basins filled with peat, were examined. The elongation of such lakes and the development coefficient of their shorelines are very low. The mean depth is close to the maximum value (7.0 ± 4.8 and 7.8 ± 3.9 m, respectively), as the lake bottom is normally flat and the basin walls are often vertical. In terms of morphometric features, the peatland lakes were divided into large (1.92 ± 1.12 ha) and small (0.33 ± 0.33 ha). The former are surrounded by a relatively narrow belt of peatlands and characterized by low values of Ohle coefficient and Schindler factor (1.81 ± 2.04 and 0.32 ± 0.13), which makes them very susceptible to the effect of peatlands. The smallest lakes are located in the central part of big peatlands. Their values of Ohle coefficient and Schindler factor are five times higher, whereas their volume is ten times less (13,750 m³ as compared to 125,000 m³; p < 0.001). The bottom slope angle is considerable. In peatland lakes, there is little space that could be occupied by vegetation. In deep moraine-dammed lakes plants occur only on vertical walls, whereas in shallow water bodies, plants also thrive on the bottom.