SUSPENDED-MATTER PARTICLE-SIZE IN SOME WEST-EUROPEAN ESTUARIES .1. PARTICLE-SIZE DISTRIBUTION

Particle size of suspended matter was measured in five Northwest-European estuaries by Coulter counter and pipette analysis, and in situ with a suspension camera. Particle sizes measured by Coulter counter and pipette analysis became finer at the saltwater contact, but the in situ particle (floc) sizes did not show this. It is concluded that the particle size measured by Coulter counter and pipette analysis indicates the fragility (or firmness) of the flocs. The in situ particle size is variable, and is not related to changes in salinity, the content of organic matter in the flocs or the bulk composition of the organic matter. There is no consistent evidence that salt flocculation is an important factor in river mouths.