Die Bakterien- und Keimzahlen im Oberlauf der Donau bis Ulm
[Direct counts and plate counts of bacteria in the Danube between Breg Spring and Ulm]
published: Oct 1, 1972
In the Breg Spring, and at 7 other stations of the Danube above Ulm, the number of bacteria counted by the direct method, and the number of heterotrophic, saprophytic bacteria has been determined. Highest numbers could always be found during low water level below the outfalls of sewers. With the microscopic method numbers were found to range from 1900/ml at Breg spring to 36 000 000/ml at Tuttlingen, and with the plate count method from 49/ml to 640 000/ml at the same stations. The ratio direct count to plate count can be employed only with reservation to indicate the water quality. In spite of a high concentration of bacteria, the bacterial load is smallest at low water-level and highest during floods. Along the section of river investigated the bacterial load increases parallel to the rising flow.