Geology and developmental pathways of Sphagnum peatland-lake ecosystems in eastern Pomerania

We in ves ti gated sed i ments of three Sphag num peatland-lake eco sys tems lo cated in Tuchola for est, both in mo raine (Ma³e Leniwe near Rekowo) and outwash plain (Dury and Rybie Oko) land scape. Geo log i cal cross-sec tions were stud ied for each ba sin. Char ac ter is tic fea ture of these eco sys tems is the pres ence of float ing mats en croach ing the lakes and de po si tion of highly hy drated sed i ments be low the float ing mat. Prin ci pal con di tions fa vour ing the de vel op - ment of peatland-lake eco sys tems are (1) lo ca tion of the lake in a sandy, non-cal car e ous catch ment over grown by co - nif er ous for est, (2) steep ness of the lake ba sin, what pre vents emerged macrophytes suc ces sion and (3) the depth of the ba sin sig nif i cantly ex ceed ing 10 m to avoid com plete in fill ing of the lake ba sin. The de vel op men tal path way in the Dury I ba sin in di cates a shift in lake en vi ron ment from neu tral to acid one. Af ter ini tial de vel op ment of Charophytes, Potamogeton and Najas ex panded, which later on, were suc ceeded by Sphag num due to acid i fi ca tion of the lake wa ter. Ini tial stages of the de vel op ment of the lakes were de ter mined mainly by allogenic fac tors, whereas in later stages autogenic fac tors (de vel op ment of float ing mat and peat acid i fy ing the lake wa ter) played fun da men tal role