Abnormal Chemical Element Concentrations in Lichens of Isle Royale National Park
Bennett JP. 1995. Abnormal Chemical Element Concentrations in Lichens of Isle Royale National Park. Environmental and Experimental Botany. 35:259-277
Lichens have been used to monitor changes in deposited airborne chemical elements in many areas for many years, but few studies have focused on relatively pristine areas suspected of experiencing slightly elevated pollution. Detection of subtle patterns of slightly elevated pollutants calls for developing several lines of evidence as opposed to single line studies used in polluted areas. This study of two lichen species, Hypogymnia physodes and Evernia mesomorpha, in Isle Royale compares the concentrations and ranks of elements with the concentrations and ranks of the elements in the earth's crust, changes in element concentrations over a nine year period, and the geography of element concentrations in the park. Sulfur, Zn, Pb, Cd and Se were all elevated in both species and higher in rank compared to the concentrations and ranks in the earth's crust. Toxic elements increased 123% in Hypogymnia and 62% in Evernia over nine years, compared to increases of 45% and 59% for non-toxic elements in each species respectively. Geographically, the lichens at certain localities with higher exposures experienced higher than average element concentrations. Finally, tissue concentrations of Mn, S and Se at some localities are above levels known to be either toxic or similar to those found in polluted areas. These four lines of evidence suggest that Isle Royale National Park is experiencing the onset of chronic air pollution stress from a number of sources.
- Type
- Journal Article
- Authors
- Bennett, James
- Units
- ARD , ISRO
- Keywords
- Air Quality, AIRBIB, ARD_Park-Air-Info_Collection, Atmospheric Sciences, Contaminants, Deposition, Evernia mesomorpha (lichen), Heavy Metals, Hypogymnia physodes (lichen), Indicator Species, Lichen (Mycophycophyta), Mercury, Plant Studies, Pollution, Toxics