Enhanced Wind Linked to Ozone Depletion Influences Photoprotective Responses in Antarctic Mosses via Water Stress

Abstract Climate change, including ozone depletion, has altered wind regimes around Antarctica in recent decades, intensifying environmental stress on coastal moss communities. However, the physiological impacts of wind on mosses remain poorly understood. This study explored the potential climatic drivers of wind speed (WS) changes and investigated the physiological effects of variation in WS on three dominant Antarctic moss species ( Schistidium antarctici , Ceratodon purpureus , and Bryum pseudotriquetrum ) in the Windmill Islands, East Antarctica. Our analysis showed that ozone depletion contributed to increased regional summer WS. To investigate biological responses, we examined changes in moss turf water content (TWC), the effective quantum yield of photosystem II [Y(II)], and pigment profiles between two growing seasons with contrasting climatic conditions. The 1999–2000 season was windier, colder, and less humid compared with the 2002–2003 season. Redundancy analysis (RDA) revealed that WS was the strongest predictor of moss physiological performance, explaining 31.8% of the variation in TWC and 37.4% for Y(II), both of which were negatively correlated with WS ( p < 0.0001). In the cosmopolitan moss species ( C . purpureus and B . pseudotriquetrum ), xanthophyll cycle photoprotection increased significantly ( p < 0.0001) under higher wind conditions but decreased with higher TWC ( p < 0.001). No such pattern was observed in the endemic S . antarctici . Our results suggest that increasing summer WS, associated with a more positive Southern Annular Mode, is exacerbating the desiccation of these coastal East Antarctic moss communities, thereby favoring the expansion of cosmopolitan species and displacing the endemic moss.