Engineering and Earth and Ocean Sciences

Description

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Bed stability in riverine or estuarine hydrological systems is altered by the existence and activity of microorganisms such as bacteria and diatoms. Through secretion of polymeric materials, they are able to weakly cement sediment grains, a process known as bio-stabilisation. The combination of this binding process together with the flow characteristics and river/estuarine morphology will control bed erosion and sediment mobility in such environments.

Contents

This project will comprise laboratory investigations into the enhancement of bed stability by microbial growth, in particular to understand how the presence of microbial exudates and subsequent biostabilisation affects the dynamics of sediment mobility, and in particular the threshold of motion of bed sediment. Current understanding of the threshold of motion has been developed from experimental studies using clean, non-cohesive sediments where the bed mobility is considered only in terms of the physical interaction between the flow properties and the bed particles. Important objectives include the determination of properties of sediment/microbial aggregates and the impact of spatially heterogeneous biostabilisation on flow processes and subsequent patterns of bed erosion.