ISSN:
1573-5117
Keywords:
phytoplankton
;
crustacean plankton
;
long-term observation
;
interrelationships
;
Secchi depth
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Fifteen years of data (1975–1990) on the phyto- and crustacean plankton in the meso/eutrophic Saidenbach Reservoir were analysed to reveal correlations between these groups or members of them. The weekly or fortnightly samples were collected from different depths and times, and were integrated to form seasonal averages. For the dominant organisms, summer means of abundance were plotted against one another. Among the Crustacea, Daphnia galeata exerts a strong influence on nanoplankton resulting in an increased Secchi depth in years with a high standing stock of Daphnia. No such correlations were found for Eudiaptomus and the Cyclopoida, which are not able to remove such small particles. The abundance of Daphnia showed no obvious effects on Cyanophyta, colony forming Chlorophyta and Asterionella formosa. This implies that in the Saidenbach Reservoir, factors other than crustacean grazing are of crucial importance for the population dynamics of the latter algal groups. It is shown, that the influence of the Crustacea on the phytoplankton is evident not only for short periods, i.e. in clear-water stages, or in biomanipulated lakes, but also can be observed under ‘non-manipulated’ conditions for longer time periods.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00032017
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