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

Lichens and mosses constitute the bulk of plant biomass in terrestrial
ecosystem of continental Antarctica. 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.
Possible effects of predicted climatic changes on biogeochemistry of Antarctic
terrestrial ecosystems were discussed.