title: Iron content and its relations to the sulphur and titanium contents of epiphytic and terricolous lichens and pine bark in Finland.
abstract: The iron content was studied in the epiphytic lichens Hypogymnia physodes (L.) Nyl. and Pseudevernia furfuracea (L.) Zopf, in the terricolous lichens Cladina sp. and Peltigera aphthosa (L.) Willd., and in pine bark collected from 31 sites in Finland. There appeared to be differences between lichen species, epiphytes having generally higher concentrations. The iron content of H. physodes was highly significantly correlated (p<0.001) with its sulphur content, reflecting the relations of these elements in precipitation. The highly significant correlations between the iron and titanium contents indicated differences of the phorophytes. The iron/sulphur ratio of H. physodes on pine was 1.3 and on birch 1.4 and iron/titanium ratios were 10.4 and 11.3 respectively. The iron content of Cladina sp. showed highly significant parallel correlations (p<0.001) with its sulphur and titanium contents. The iron/titanium ratio decreased from 9.6 to 8.2 when the iron content increased by 95%, the sulphur content being equal. The iron/titanium ratio of Cladina sp. was nearly identical to that of P. furfuracea. The relation between iron and sulphur, and the fraction of soluble and insoluble iron in precipitation versus lichens and pine bark were considered. Special attention was paid in the discussion to differences in substrate: pine and birch bark for H. physodes, and soil for Cladina sp.
authors.affiliation: Ecological Laboratory, Department of Environmental Sciences, University of Kuopio, P.O. Box 1627, SF-70211 Kuopio, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Takala
authors.forename: H
authors.initials: H
authors.lastname: Olkkonen
authors.forename: R
authors.initials: R
authors.lastname: Salminen