Quantifying sediment resuspension and internal phosphorus loading in shallow near-shore areas in the Gulf of Finland

Sediment resuspension was quantified in shallow, sheltered and semi-exposed coastal areas in the Gulf of Finland. Cylindrical sedimentation traps were placed at six locations including emergent aquatic vegetation stands (Phragmites australis), submerged vegetations stands (Myriophyllum spicatum, Potamogeton pectinatus and Potamogeton perfoliatus) and unvegetated shallow (1-1.5 m) areas. During the study period (19 May-29 September 2009. sampling interval of two weeks), there was a seasonal development of macrophyte stands, as well as variation in suspended matter and sediment resuspension. The resuspension-inhibiting effect of macrophytes was found as decreasing resuspension values in concordance with the increasing macrophyte density during the growing season. However, measured phosphorus resuspension was highest among emergent macrophytes due to high concentration of phosphorus in sediments. A linear regression model for resuspension in shallow coastal areas was developed with which sediment resuspension rate may be predicted.