Combined effects of temperature and emersion-immersion cycles on metabolism and bioenergetics of the Pacific oyster Crassostrea (Magallana) gigas

Life on tidal coasts presents physiological major challenges for sessile species. Fluctuations in oxygen and temperature can affect bioenergetics and modulate metabolism and redox balance, but their combined effects are not well understood. We investigated the effects of intermittent hypoxia (12h/12h) in combination with different temperature regimes (normal (15 degrees C), elevated (30 degrees C) and fluctuating (15 degrees C water/30 degrees C air)) on the Pacific oyster Crassostrea (Magallana) gigas. Fluctuating temperature led to energetic costly metabolic rearrangements and accumulation of proteins in oyster tissues. Elevated temperature led to high (60%) mortality and oxidative damage in survivors. Normal temperature had no major negative effects but caused metabolic shifts. Our study shows high plasticity of oyster metabolism in response to oxygen and temperature fluctuations and indicates that metabolic adjustments to oxygen deficiency are strongly modulated by the ambient temperature. Co-exposure to constant elevated temperature and intermittent hypoxia demonstrates the limits of this adaptive metabolic plasticity.

Automated summary

Life on tidal coasts presents challenges for sessile species due to fluctuations in oxygen and temperature. This study investigated the effects of intermittent hypoxia and different temperature regimes on Pacific oysters. The results showed that fluctuating temperature led to metabolic rearrangements and protein accumulation, elevated temperature caused high mortality and oxidative damage, and normal temperature caused metabolic shifts. The study highlights the plasticity of oyster metabolism in response to oxygen and temperature fluctuations, with metabolic adjustments strongly influenced by ambient temperature.