Focused study on metal allocation patterns in Usnea antarctica lichen from James Ross Island

This study employed laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to investigate the spatial distribution of essential and potentially toxic elements in Usnea antarctica from James Ross Island, Antarctica. A triple quadrupole ICP-MS system coupled with a new laser ablation system enabled 15 μm spatial resolution, facilitating the acquisition of detailed bioimages. Bioimages captured Cu, Co, Ni, Mn, Fe, Zn, Cr, Pb, and U allocation across lichen pseudotissues, revealing allocation patterns between the cortical, photobiont, and medullary regions. These elemental distribution trends support previous Antarctic biomonitoring studies, differentiation between long-range transport, structural embedding and essential roles of inorganic nutrients. High-speed triple-quadrupole acquisition and refined laser probe spatial resolution provided an improved framework for elemental bioimaging in complex biological matrices. The results indicate preferential accumulation of Fe and U in the cortical layer, while Cr, Cu, Ni, Zn, and Pb exhibited a gradient from the cortex to the medulla. These findings support those of previous Antarctic biomonitoring studies, reinforcing studied patterns of atmospheric deposition and geogenic absorption in lichenized fungi with physiological implications of both essential as well as potentially toxic roles of metals.