Julie, Beccy, Irvine and Jack are just back from two weeks away for an interdisciplinary field campaign carried out in the Dee estuary and involving several institutes, including SERG, as part of the NERC-funded COHBED project. Physical measurements of sediment behaviour (sandy and cohesive mixed sediments) were observed during consecutive tidal cycles using ripple profilers, as well as state of the art optical and acoustic instruments deployed by COHBED partner institutes (NOC Liverpool, Plymouth, Bangor and Hull universities), while the biological characteristics of the sediment at each site were assessed by the SERG members. These measurements were related to the current velocities at 3 sites on the intertidal flats, with biological and physical sediment properties assessed during low tide and also during tidal immersion.
The influence of the microphytobenthic community and the adhesive polymers produced by these organisms, on sediment erosion and bedform formation was determined. Temporal variation in biological properties within the sediment bed were assessed through repeat sampling both over and within tidal immersion periods, and the dissolution of the polymers into the water column was determined with a time series of water samples taken close to the bed during tidal immersion.
The measurements observed across all institutes will provide a comprehesive dataset allowing the inclusion of both physical and biological properties on sediment behaviour, in particular sediment erosion, transport and ripple formation in future predictive models.