To 6 vessels with P. australis and 6 with non-vegetated sediment a copper saline solution was added, a solution with a concentration chosen to result in a sediment copper concentration of 270 lg g1 (a concentration corresponding to the ERM (effects range-median)value, which is the sediment quality guideline that indicates the pollutant concentration above which is frequent to occur adverse biological effects, in marine and estuarine sediments