Abstract
Organisms inhabiting tidal mixing-front zones in shallow temperate seas are subjected to large semidiurnal temperature fluctuations in summer. The ability to optimize energy acquisition to this episodic thermal oscillation may determine the survival, growth and development of these ectotherms. We compared the physiological and molecular responses of Haliotis discus hannai cultivated in suspended cages to fluctuating or stable temperature conditions. Several physiological indicators (respiration, excretion rates and O:N) were measured in both conditions, and alterations in the proteome during thermal fluctuations were assessed. No summer mortality was observed in abalone cultivated in fluctuating temperatures compared with that at stable high temperatures. Metabolic rates increased sharply during stable warm summer conditions and fluctuated in accordance with short-term temperature fluctuations (20–26 °C). Ammonia excretion rates during acute responses were comparable in both conditions. When abalone were exposed to fluctuating temperatures, enzyme activities were downregulated and structure-related protein expression was upregulated compared with that at an acclimation temperature (26 °C), highlighting that exposure to low temperatures during fluctuations alters molecular processes. Our results reveal that modulation of physiological traits and protein expression during semidiurnal thermal fluctuations may buffer abalone from the lethal consequences of extreme temperatures in summer.
Highlights
The temperature dependence of physiological processes in marine ectotherms is well recognized[1,2]
We evaluated the thermal dependence of the metabolic rate of the abalone in response to daily temperature fluctuations under controlled conditions, comparing this with the responses of those acclimated to seasonal temperature conditions (Fig. 1)
The daily temperature fluctuation was largest at the NM of all cages (ANOVA, F2,27 = 23.61, P < 0.001; Tukey test, P < 0.05)
Summary
The temperature dependence of physiological processes in marine ectotherms is well recognized[1,2]. Given the expected acute responses of abalone to the prevalence of fluctuating thermal conditions and their mortality across a widespread cultivation area around Wando Island in summer, we hypothesized that the physiological responses of abalone to thermal fluctuations would limit their ability to maintain growth and performance compared with those acclimated to stable thermal conditions To test this hypothesis, we evaluated the thermal dependence of the metabolic rate of the abalone in response to daily temperature fluctuations under controlled conditions, comparing this with the responses of those acclimated to seasonal temperature conditions (Fig. 1). We combined physiological analysis with isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative mass spectrometry (MS) of the abalone proteome to highlight the regulatory molecular mechanisms behind their physiological performance in response to semidiurnal temperature fluctuation[32,33]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
