Synergistic effects of ocean acidification and warming on the thermal tolerance and locomotion of a sea urchin

VENERUS, LEONARDO ARIEL; CHINDRIS, ANUTA; DOMENICI, PAOLO; ANTOGNARELLI, FABIO; MANRÍQUEZ, PATRICIO; MARRAS, STEFANO; SATTA, ANDREA; RODRIGO TORRES

Sevilla

Congreso; SEB Seville 2019; 2019

Society for Experimental Biology

Recent studies have shown that ocean acidification and warming, driven by anthropogenic carbon dioxide (CO2) emissions, can affect the behaviour and physiology of aquatic animals. While each isolated stressor has been studied extensively, their synergistic effects are less known. Here we tested the combined effect of medium-term (30 days) exposure to elevated CO2 and different temperatures on the thermal tolerance and locomotion of the sea urchin Paracentrotus lividus. Individuals exposed to one of four treatments (two CO2 levels, 400 and 1000 ppm and two temperatures, 14 and 24°C) were tested for their critical maximal (CTmax) and minimal (CTmin) temperature, the highest temperature for self-righting behaviour (TSR) and their horizontal and vertical locomotion. We found that high temperature had a positive effect on all the variables measured compared with the combined exposure to elevated CO2 and high temperature or the independent effect of elevated CO2. Exposure to high temperature led to an increase in CTmax , TSR and the locomotor performance during horizontal and vertical displacement. By contrast, we observed littleinfluence of elevated CO2, suggesting that thermal tolerance and locomotion were robust to this environmental stressor. Knowledge of how these traits may change as a result of concurrent exposure to elevated CO2 and high temperatures represents an important step to predict the responses of this species to climate change.