After a high water event of the River Danube in April 1994, bacterial cell numbers were determined in newly formed deposits in a backwater near Hainburg (Lower Austria) within a time course of 140 days. This data set shows that expressing bacterial numbers per fresh sediment volume, per sediment dry mass, or per pore-water fluid volume, respectively, yield significantly different results and ecological conlusions. These findings refer particularly to intra-study and time-course comparisons as presented in our case. Bacterial cell numbers expressed per gram sediment dry mass revealed statistically significant differences between the beginning and the end of the study, whereas expressed per cm3 of fresh sediment or fluid volume of sediment pore water, no statistical difference could be detected. It is argued that these differences were caused by physical sediment compaction and mineralisation processes over the considered time-course. Such mechanisms may simulate biological activity if some basic sediment parameters are neglected and thus standardisation has to be done with caution for the particular situation being observed.
- Bacterial numbers
- Newly deposited sediments
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science