Abstract

Seawater desalination raises concerns about its environmental repercussions, particularly the impact of brine discharge on benthic communities. In this study, we evaluated the effects of desalination and artificial brines on the sea anemone Anthothoe chilensis , following its observed proliferation near a brine outfall from a Chilean desalination plant. We measured biomarkers for oxidative stress (ROS content, lipid peroxidation, and protein carbonylation), antioxidant response (thiols), and osmotic stress (free amino acids and proline) in individuals collected from a brine discharge pipe (similar to 56 psu) and compared them to a population living in natural seawater salinity. Additionally, we conducted controlled laboratory experiments where A. chilensis specimens were exposed to a control salinity of 33 psu and to elevated salinities of 37 and 42 psu for 24 and 48 h. Results revealed a significant decrease in oxidative damage biomarkers, such as protein carbonylation and ROS content, along with an increase in free amino acids, proline, and thiols content at higher salinity levels, particularly under controlled conditions. These findings demonstrate the remarkable efficient cellular stress responses of this highly halotolerant species, which could potentially promote risky A. chilensis blooms in brine discharges areas. Additionally, this study provides valuable biomarker information for assessing the short-term impacts of brine discharges, which can be used in biomonitoring programs within the desalination sector.