Besonderheiten bei der Ermittlung der Primärproduktion in der Elbe aus Sauerstoff-Ganglinien. Some Particularities in Estimating Primary Productivity in the River Elbe Using Oxygen Time Curves

The phytoplanktonic primary production was estimated in the River Elbe (average flow 325 m³/s) by ODUM 's twin and single curve analysis of changes in the oxygen content (1- and 2- SGA). The results were affected by the severe and varying waste water load and the non-uniform conditions along the upstream river stretch. It is shown how the gross primary productivity was corrected by using the photosynthesis-light-relationship. At favourable measuring sites, single curve analysis gives similar values as ODUM 's twin curve method. But they scatter more when applied to establish the photsynthesis-light-relationship.