The influence of pH on trace element uptake by an alga (Scenedesmus pannonicus subsp. Berlin) and Fungus (Aureobasidium Pullulans)

Abstract

Experiments were carried oud in order to obtain information on the uptake characteristics of metals in the algal and fungus components of lichens. The uptake of (115)Cd, (65)Zn, (64)Cu, (140)La, (187)W, (75)Se, and (76)As in the alga Scenedesmus pannonicus, subsp. Berlin and the fungus Aureobasidium pullulans was determined during 11 days of incubation at pH 5 and pH 7. The results indicate different acid-sensitivity of the alga and the fungus. The metal uptake in the alga was generally faster at pH 7, in the fungus uptake rates were higher at pH 5. In both the alga and the fungus for different pH-values hardly any differences in ultimate metal levels could be observed for Cd(2+), Zn(2+), La(3+), and SeO inf3 (sup2-) . In algae, the ultimate levels of the accumulated anionic forms of W and As appeared to be independent of pH; in the fungi the ultimate W and As levels were higher at pH 5. No differences could be observed in the Zn(2+) accumulation capacities of both organisms. The As accumulation capacity of the alga was estimated to be about 10 times the As uptake capacity of the fungus. The results indicate the component-specific uptake and accumulatiom behaviour in intact lichens.