OSPAR request to investigate spatial representation of existing CEMP sediment monitoring stations
ICES advises that there is nosingle method that can be recommended to determine the geographic representativeness of existing sediment monitoring stationsthat would meet all monitoring purposes. Four different methods might be considered,depending on the monitoring purpose:
i) Sediment transport models are not yet sufficiently developed to be able to describe (with sufficient detail on a region scale) where sampling stations should be located;
ii) Existing monitoring stations that are in areas of fine sediment can be used for regional-scale assessment of status in relation to GES for MSFD Descriptor 8,based on whole sediment concentrations (i.e. not normalized or sieved). Monitoring of temporal change should,however,use data from sieved samples.If only sieved samples are available, then whole sediment concentrations can be back-calculated from concentrations in the sieved fraction.
iii) There is no strong relationship between variability of concentrations and size of a geographic area/strata.
iv) Visual representations of existing data can provide information on the geographic pattern of concentrations of sediment contamination.
It is apparent from several lines of enquiry that the degree of variability will differ for different substances and between geographic areas.
Published under the auspices of the following ICES Steering Group or Committee