Abstract

Environmental heterogeneity plays a key role in spatio-temporal distribution of organisms, their ecology and their evolutionary biology, with their physiological response, or tolerance to the environment defining their distributional range. The macroalgae of the sub-Antarctic ecoregion of Magallanes are subject to a wide range of environments, resulting from geomorphological processes (glacial erosion in the Quaternary), oceanographic gradients, and drastic seasonal variations of photoperiod and irradiance (winter < 8 h of light, summer > 17 h). We examined the tolerance response of the brown alga Lessonia flavicans to contrasting environments (three salinities, two temperatures, and two photoperiods) under controlled laboratory conditions. Our results suggest that L. flavicans has limited salinity tolerance that is affected by temperature and photoperiod. Summer temperature (9 A degrees C A +/- 0.02) and photoperiod (18:6 h L:D) and salinity 32 psu seem optimal conditions for L. flavicans sporophyte development. Results of the present study provide key information for culturing a species of high economic and biological value, and could aid in predicting the species potential tolerance response to environmental fluctuations in the wake of global changes.