Original paper

Microbial investigations in rivers VII. Seasonal variations of bacterial numbers and activity in eutrophied rivers of Northern Germany

Gocke, Klaus; Rheinheimer, Gerhard

Archiv für Hydrobiologie Volume 112 Number 2 (1988), p. 197 - 219

34 references

published: Apr 21, 1988

DOI: 10.1127/archiv-hydrobiol/112/1988/197

BibTeX file

ArtNo. ESP141011202002, Price: 29.00 €

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Abstract

Over a period of 2 years water samples were taken at monthly intervals from a midstream station of the Elbe and the Trave Rivers (Northern Germany). Besides physical and chemical parameters, the following variables were investigated: total bacterial numbers and biomass by means of direct microscopical counts, numbers of saprophytes, numbers of coliform bacteria and the turnover times (Tt) and turnover rates (Tr) of glucose, aspartic acid and acetate as a measure of the heterotrophic activity. The average annual values found for the Elbe and Trave Rivers, respectively, were: total numbers of bacteria 11.4 x 106 and 10.5 x 106cells ml-1bacterial biomass 154 and 129 µg Cl-1 saprophytes 82.5 x 103 and 48.9 x 103 cells ml-1; turnover time for glucose 1.89 and 3.18 h; Tt for aspartic acid 1.20 and 2.10 h; Tt for acetate 1.12 and 1.94 h. The heterotrophic activity (Tr) shows a clear annual periodicity with high values in the summer and lower ones in the winter. The differences between the most extreme values, which for both rivers are less than one order of magnitude, are more pronounced in the Trave. This is due to the fact that, in this river, total bacterial numbers are highly significantly correlated with the temperature, so that the influence of number and temperature on the turnover rates works in the same direction. In the Elbe, on the other hand, no significant correlation between temperature and total bacterial numbers was observed. Thus, in this river the increase in heterotrophic activity during summer is relatively small and almost completely explainable by the rise of the temperature alone.

Keywords

Elbe • Trave Rivers • Northern Germany • saprophytes • glucose • aspartic