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Aggregate‐Associated Bacteria and Heterotrophic Flagellates in the River Elbe – Their Relative Significance along the Longitudinal Profile from km 46 to km 583
Author(s) -
Wörner Ute,
ZimmermannTimm Heike,
Kausch Hartmut
Publication year - 2002
Publication title -
international review of hydrobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 1434-2944
DOI - 10.1002/1522-2632(200205)87:2/3<255::aid-iroh255>3.0.co;2-r
Subject(s) - heterotroph , chlorophyll a , dry weight , bacteria , nutrient , zoology , environmental science , phytoplankton , biology , environmental chemistry , chemistry , botany , ecology , genetics
The aim of this study was to investigate the occurrence of microaggregates and their colonization by bacteria and heterotrophic flagellates along the longitudinal profile of the River Elbe from km 46 in Dresden up to km 583 near Hamburg. As additional parameters, the content of chlorophyll a , the dry weight of the suspended particles and the concentration of nutrients in the river were measured. Abundances of aggregates ranged between 322 and 1196 aggregates ml –1 with the lowest value at the uppermost location. Aggregate dry weight also showed the lowest value at this location with a mean of 0.02 g l –1 . The chlorophyll a ‐content revealed a gradual increase from the uppermost to the lowest reach with a maximum of 216 μg l –1 at km 583. The total abundances of bacteria and heterotrophic flagellates reached values of 9.9 · 10 6 cells ml –1 and 1.2 · 10 3 cells ml –1 , respectively. The percentages of aggregate‐associated cells in the river water ranged from 2.2 to 13.3% in the case of bacteria and from 16.7 to 73% for heterotrophic flagellates. The highest values occurred in both cases in the midreaches between km 475 and km 275; these coincided with high concentrations of aggregates. In general, low abundances of cells were detected in the upper part of the river, but high values were reached when numbers of cells were related to aggregate volume and dry weight.