Species-specific responses of tropical gastropods to moderate ocean warming

Global change is leading to warmer sea surface temperatures. The responses of marine species to such changes are likely to be dependent upon whether the change drives them past their thermal tolerance limit; a boundary beyond which critical physiological processes can no longer be maintained. It has been suggested, therefore, that tropical marine species may be particularly susceptible to ocean warming as they live closer to their thermal tolerance limits than colder-water species. There is also a growing body of evidence in the literature of differences in thermal tolerance limits among tropical species. To examine these ideas, here we compared the physiological capabilities of gastropod species found in the tropical waters of Hong Kong. We first exposed the gastropods to either current summer temperatures, or those anticipated for the end of the century. We quantified how prolonged exposure to moderate warming modified gastropod survival, feeding rates, growth rates, and oxygen consumption. Collectively, these results indicate that, in contrast to expectations, moderate warming may have limited effects on these gastropod species. We then exposed the gastropods to an acute thermal ramp and quantified their oxygen consumption rates. The results obtained from this additional measure indicate that chronic exposure to warming can influence the potential of gastropods to acclimate and survive. Ocean warming can change, or maintain, the physiological processes of gastropods, potentially having consequences for the ecosystems they occur within.