SEASONAL-VARIATION OF ELEMENTAL STATUS IN THE LICHEN RAMALINA-MENZIESII TAYL FROM 2 SITES IN SOUTHERN CALIFORNIA - EVIDENCE FOR DRY DEPOSITION ACCUMULATION

In southern California the lichen Ramalina menziesii was transplanted from a relatively unpolluted area to a highly polluted area for three periods over a year. During each period multi-element analyses of both water leachable extracts and residual fractions from the leached thallus were analyzed at 2-week intervals. Total concentrations were calculated by adding these two measurements. Total concentration of most elements did not exhibit distinct seasonal patterns but the higher concentrations exceeded background levels by factors of 1.3-3.7, depending on the element. In contrast, the elements in the leachates at the control and the polluted site exhibited distinct seasonal patterns with higher concentrations generally present in summer than in winter. High leachable concentrations were only found during dry periods, and consequently the leachable fraction was assumed to represent primarily dry deposition accumulation, particularly as the magnitude of the differences was higher at the polluted site. These elemental patterns reflected not only atmospheric deposition patterns, but also intracellular release of elements as injury occurred and to a lesser extent accumulation of marine aerosols and soil particulates. © 1990.