Highlights
- The effects of thermal history on thermal threshold and physiology were assessed.
- Gastropods acclimated to warmer environments had higher thermal threshold (CTmax).
- Warm-acclimated gastropods were metabolically less active than cool-acclimated ones.
- Energy conservation appeared to be a strategy for thermal acclimation.
- Long-term thermal acclimation may allow marine organisms to adjust to climate change.
Abstract
Ocean warming is predicted to challenge the persistence of a variety of marine organisms, especially when combined with ocean acidification. Whilst temperature affects virtually all physiological processes, the extent to which thermal history mediates the adaptive capacity of marine organisms to climate change has been largely overlooked. Using populations of a marine gastropod (Turbo undulatus) with different thermal histories (cool vs. warm), we compared their physiological adjustments following exposure (8-week) to ocean acidification and warming. Compared to cool-acclimated counterparts, we found that warm-acclimated individuals had higher thermal threshold (i.e. increased CTmax by 2°C), which was unaffected by the exposure to ocean acidification and warming. Thermal history also strongly mediated physiological effects, where warm-acclimated individuals adjusted to warming by conserving energy, suggested by lower respiration and ingestion rates, energy budget (i.e. scope for growth) and O:N ratio. After exposure to warming, warm-acclimated individuals had higher metabolic rates and greater energy budget due to boosted ingestion rates, but such compensatory feeding disappeared when combined with ocean acidification. Overall, we suggest that thermal history can be a critical mediator of physiological performance under future climatic conditions. Given the relatively gradual rate of global warming, marine organisms may be better able to adaptively adjust their physiology to future climate than what short-term experiments currently convey.
Leung J. Y. S., Russell B. D., Coleman M. A., Kelaher B. P. & Connell S. D., in press. Long-term thermal acclimation drives adaptive physiological adjustments of a marine gastropod to reduce sensitivity to climate change. Science of The Total Environment. Article (subscription required).
