A laboratory controlled biological response of black lichen communities to prolonged seawater submersion as a climate-change-relevant stressor

Climate change also affects the conservation of outdoor cultural heritage. The coastal Phoenician archaeological site of Motya could be affected by rising sea levels induced by climate change, with a predicted difference of about +59 cm above local mean sea level by 2100 in the Mediterranean Sea. If the maximum sea level rise occurs, the archaeological structures are expected to be submerged. On Motya Island, the stone walls of the archaeological site are colonised by black lichens, which are complex symbiotic microbial communities that colonise a variety of substrates, causing aesthetic and physicochemical degradation. This study investigated how lichens respond to prolonged submersion under controlled laboratory conditions, which is relevant to potential future flooding scenarios. The findings provide preliminary experimental evidence of the effects of seawater submersion as a stressor relevant to climate change on the microbial profile, and its implications for the conservation of stone artwork.