Abstract

In recent decades, marine heatwaves (MHWs) have increased in frequency, duration, and intensity, causing concerns about their impact on marine organisms. The aim of this study was to evaluate the impact of an extreme MHWs on oxygen consumption in Acanthina monodon, exposing them to two consecutive exposure/recovery periods, followed by a late recovery phase. Results showed a reduction in oxygen consumption during the initial exposure, but in subsequent exposures, the snails recovered their aerobic capacity, with no significant differences between treatments up to the 2nd recovery. Survival showed 60 % rate by day 18, while the control maintained a 100 % rate. The study suggests that A. monodon can acclimate to extreme MHWs by adjusting its oxygen consumption, potentially through memory-based plasticity developed from prior exposure. Although this response may enhance short-term survival, this adaptation appears to involve associated costs, as suggested by the mortality observed, potentially resulting from cumulative damage. These results underscore the importance of further research assessing the cellular, molecular, and reproductive consequences of extreme thermal events, particularly in the context of ongoing global change. These results highlight the capacity of A. monodon to acclimate to extreme thermal events through physiological adjustments, while also revealing the potential costs associated with prolonged or repeated exposures in the context of ongoing global change. © 2025 Elsevier B.V.