The presented dissertation follows up on hydrochemical and vegetation ecology issues that were started during the previous bachelor and master studies at Leibniz Universität Hannover in the form of study and research projects as well as the respective final theses and are to be investigated in depth and purposefully as part of the doctorate.The focus is on spatio-temporal variable processes within a limnic ecosystem, which is exemplarily represented by the "Großes Heiliges Meer" in the nature reserve "Heiliges Meer" in the district of Steinfurt, Germany. The long-term development of the vegetation zonation of the Großes Heiliges Meer from a spatiotemporal perspective is investigated as well as the comparatively short-term hydrochemical diurnal processes of selected parameters.After this summarizing overview, in which the goal of this work is formulated, compact conceptions of the investigation area as well as the vegetation-scientific and hydrochemical-analytical investigation methodology follow. In addition, the concept of space-time dynamics is explanatorily differentiated into its spatial and temporal components in view of its importance for this work. The two large main parts contain the results and analyses of the hydrochemical diurnal dynamics in the annual cycle as well as the presentation of the vegetation composition of the present water body. Finally, the discussion of the results and a conclusion with an outlook are given.The aim of this dissertation is to present a comprehensive overview of the diurnal and annual cycles of selected hydrochemical parameters such as oxygen content for a stillwater of the North German Plain and to contrast these dynamics with spatiotemporal long-term processes such as vegetation development. In addition, however, both dynamics are highlighted in isolation with respect to their contribution to the limnetic ecosystem. Thus, this work is intended to be a complementary component for the Großes Heiliges Meer that has been intensively investigated and described from a natural science perspective by numerous works.