Abstract
Marine animals are challenged by chronically raised temperatures alongside an increased frequency of discrete, severe warming events. Exposure to repeated heat shocks could result in heat hardening, where sub-lethal exposure to thermal stress temporarily enhances thermotolerance, and may be an important mechanism by which marine species will cope with future thermal challenges. However, we have relatively little understanding of the effects of heat hardening in comparison to chronic exposure to elevated temperatures. Therefore, we compared the effects of heat hardening from repeated exposure to acute heat shocks and chronic exposure to elevated temperatures on thermal tolerance in the European abalone, Haliotis tuberculata. Adult abalones were exposed to either control temperature (15 °C), chronic warming (20 °C) or a regime of two events of repeated acute heat shock cycles (23–25 °C) during six months, and their thermal tolerance and performance, based upon cardiac activity, compared using a dynamic ramping assay. The cost associated with each treatment was also estimated via measurements of condition index (CI). Abalone exposed to both temperature treatments had higher upper thermal limits than the control, but heat-hardened individuals had significantly higher CI values, indicating an enhancement in condition status. Differences in the shape of the thermal performance curve suggest different mechanisms may be at play under different temperature exposure treatments. We conclude that heat hardening can boost thermal tolerance in this species, without performance trade-offs associated with chronic warming.
Original language | English |
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Article number | 103963 |
Journal | Journal of Thermal Biology |
Volume | 124 |
Early online date | 26 Aug 2024 |
DOIs | |
Publication status | Published - 30 Aug 2024 |
ASJC Scopus subject areas
- Physiology
- Biochemistry
- General Agricultural and Biological Sciences
- Developmental Biology
Keywords
- Ct
- Frontloading
- Heart rate
- Heat shocks
- Stress conditioning
- Thermal performance
- Upper thermal limits