The effect of zinc on the increase in length of five species of intertidal fucales

The growth rate of Pelvetia canaliculata (L.) Dec. et Thur., Fucus spiralis L., F. vesiculosus L., F. serratus L., and Ascophyllum nodosum (L.) Le Jolis was measured in six different concentrations of zinc (0.025–14 mg/l) during a period of ten days. No significant growth response was observed at 0.1 mg/l of zinc. A significant reduction of growth during the first two to three days of exposure to 1.4 mg/l or more was followed by no or small further decline. Apices of A. nodosum from localities with different background load of zinc (0.1–0.5 mg/l and <0.01 mg/l) showed no difference in response to 2.6 mg/l of zinc.