The Sea as major source of ions to lichens in terrestrial ecosystems of Victoria Land

On the hypothesis that cryptogams can be used as an early warning system to detect the effects of climatic changes on environmental biochemistry, we investigated the elemental composition and the main source of soluble ions to the saxicolous lichen Umbilicaria decussata in Victoria Land. Concentrations of major anions (Cl-, SO42-, NO3-), cations (Na+, Ca2+, Mg2+, NH4+) and trace elements (Al, Cu, Fe, Mn and Zn) were determined in lichens, snow, salt encrustations and wet filter papers laid on lichen supporting rocks.

Enrichment Factors calculate using Na as marine reference element were close to 1 for most of analyzed ions irrespectively of rock type. A crustal contribution of Ca, K and above all Cu was found in the lichen thalli growing on grabbo and ultramafic rocks. The uptake of marine ions in Umbilicaria thalli probably occurs directly from the snow and aerosols and indirectly through the solubilization of salt encrustation on rock surfaces.