Sediment sampling in estuaries: site selection and sampling techniques

In this chapter a range of sediment sampling techniques specifically suited to estuarine conditions are briefly described and discussed. Advice is provided about the selection of appropriate coring sites and techniques for a variety of conditions, including water depth, varying sediment composition, and sample analytical requirements. In the section on experimental design we briefly consider issues to do with sample replication from both a biological and geological perspective. During coring, alterations are inevitably made to the texture of the sediment, including compaction and water loss, resulting in changes to bulk density and the structure of the pore spaces, and physical disruption to layering. We comment on the nature of some of these disturbances, their dependency on sediment composition, which techniques to choose to minimise occurrence and, if necessary, how and when to make measurements to determine the amount of change caused by coring. Several factors need to be considered during the core recovery phase to ensure optimal retrieval of the core. These include use of core catchers and plugs to minimise or prevent loss of sediment during recovery. Freeze coring is recommended where the sediment-water interface is poorly defined or the sediments are particularly watery. Finally, we discuss transport and initial storage of core