The relative contributions of physical and microbiological factors to cohesive sediment stability

摘要

The stabilising effects of natural benthic diatom and bacterial assemblages on cohesive sediments were compared with those caused by physico-chemical binding alone. Cohesive sediment beds were reconstructed in 4 annular laboratory miniflumes, using sediment collected at 5–6 m water depth from a local fjord. The sediment was left to stabilise (consolidate) for 1, 2, 5 and 10 days, before being fully resuspended in a series of erosion experiments. The flumes were aerated and subjected to different light/dark conditions; antibiotics were used to isolate diatom from bacteria effects. During consolidation, a constant current velocity was maintained, at a speed well below erosion threshold.