ELEMENT LOSSES FOLLOWING DISTILLED WATER RINSING OF LEAVES OF THE SEAGRASS POSIDONIA-OCEANICA (L) DELILE

Rinsing of seagrasses with distilled water is often carried out prior to element analysis. The present study shows that such rinsing of the leaves of the Mediterranean seagrass Posidonia oceanica (L.) Delile re sults in significant element leakages, depending on leaf age. In adult leaves, only Fe concentrations are reduced. In younger leaves, signif icant concentration reductions occur for S, Mg, Na, Zn, Pb, Cd, Fe, Cr , and Ti, while concentrations of N, P, Ca, and Cu remain unaffected. C and K concentrations increase following distilled water rinsing owin g to weight loss by leaching of Na and probably other major ions. The relative contribution of the different age classes to total shoot weig ht implies that distilled water rinsing also affects element analysis of whole shoots. The use of distilled water rinsing prior to element a nalysis should thus be avoided.