Schlüsselprozesse im Energiehaushalt von Fließgewässern: Primärproduktion und Respiration

The energy budgets of many lotic ecosystems are strongly influenced by the adjacent terrestrial environment. The riparian vegetation is not onlyasource of energy but also controls the primary productivity. Under the closed canopy of riparian trees the growth of primary producers (algae, mosses and macrophytes) is principally fimited by fight. Therefore, the energy turnover is domina ted by the processing of organic matter. Along the continuum of ariver the ratio of primary production to organic matter processing changes with channel width and depth. The temporary loss of the autotrophic energy base caused by floods can be compensated by the pool of particulate organic matter, aresistant energy reservoir. Marginalization of the riparian tree vegetation, outfall of treated sewage and runoff from agricultural areas create optimal conditions for the growth of algae and macrophytes. Such conditions offen result in weed and water quality problems. Size and orientation of a river limit the control of the primary production by restoring the riparian wood vegetation.