Vertical distribution of the macrozoobenthos and sediment structure in the main channel of a large deep river, the Danube at river-kilometre 1889.9
Fesl, C.; Weilguni, H.
For the first time, the freeze-core technique has been applied for quantitative sampling in the main channel of a large deep river up to a water depth of 5 metres. Vertical distribution of sediment structure and fauna was investigated at four sites along a cross-section in a free-flowing part of the River Danube. Black sediment from 0.5 m downwards near the right bank indicated lack of oxygen. No tendency in mean particle size with depth could be observed. Sediment was well sorted with a preponderance of greater particle sizes. The pore space was about 30% of total sediment volume and remained constant with depth. The biota was dominated by Chironomidae, Oligochaeta and Crustacea and decreased from the left (low current velocity) to the right side and with depth. 90% of all individuals were found in the upper 40 cm. The faunal - substratum relationship was not highly correlated, with no evident pattern at high taxonomic levels.