Usnea antarctica

Table 6.9. Trace elements contents in Usnea aurantiacoatra and Usnea antarctica from Potter Cove, King George Island ((xg g dry weight)...

The objective of this preliminary study was to assess levels of Cd, Cu, Fe, Mn, Pb and Zn in two species of epilithic macrolichens Usnea aurantiacoatra (only found in maritime Antarctica) and Usnea antarctica (found in maritime and continental Antarctica) (57). Usnea antarctica has an antarctic circumpolar distribution continental and subantarctic regions. New Zealand and Tierra del Fuego (58). Table 6.9 shows the concentrations of Cd, Cu, Fe, Mn, Pb and Zn in specimens of the Antarctic lichens Usnea aurantiacoatra and Usnea antarctica in areas close to Jubany Station. Two different trends of trace metals accumulation have been identified, namely ... 

A better understanding of the different trends in the accumulation of metals observed in Usnea antarctica and Usnea aurantiacoatra demand more studies, such as the estimation of the age of lichens, their growing rate and the composition of the soil and rocky substrates in eontact with them. 

Lichens Usnea aurantiacoatra and Usnea antarctica) could be useful as monitors to evaluate the Antarctic ecosystem and to identify patterns of the deposition of atmospherically transported heavy metals. Thus, it would be possible to study variations in the spatial distribution of these elements not only at the local, but also at the regional scale. Knowing the effect of the different local and regional growth rates and evaluating metal contents of the soil, it would be possible to perform metal biomonitoring in different zones of Antarctica and of the southern hemisphere. 

Evernia mesomorpha, Lecanora stenotropa, Leptogium saturninum, Parmelia omphalodes, Ramalina terebrata, Umbilicaria decussata, Usnea antarctica 687)... 

Motivated by their wish to acquire basic knowledge on the elemental content of lichens in Antarctic regions and in Antarctica itself, a few authors collected and analyzed samples in different sites in and around this isolated continent. Bargagli et al. (1993) measured the Hg content of two species of macrolichens, Umbilicaria decussata and Usnea antartica, sampled on the coast of northern Victoria Land. These lichens contained higher Hg levels than lichens in other remote areas. It was suggested that a certain part of the airborne Hg, accumulated in the lichen, derived from local volcanic activity. 

Poblet, A., Andrade, S., Scagliola, M., Vodopivez, C., Curtosi, A., Pucci, A., Marcovecchio, J., 1997. The use of epilithic Antarctic lichens (Usnea aurantiacoatra and V. antartica) to determine deposition patterns of heavy metals in the Shetland Islands, Antarctica. Sci. Total Environ. 207, 187-194. 

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