Abstract
Marine mollusks are commonly subjected to heat stress. To evaluate the effects of heat stress on the physiological metabolism of the ark shell Scapharca subcrenata, clams were exposed to different high temperatures (24, 28 and 32 °C) for 72 h. The oxygen consumption and ammonia excretion rates were measured at 2, 12, 24, 48 and 72 h. The results indicated that the metabolic rates of the ark shell significantly increased with increasing heat stress, accompanied by mortalities in response to prolonged exposure. A metabolomics approach based on gas chromatography coupled with mass spectrometry was further applied to assess the changes of metabolites in the mantle of the ark shell at 32 °C. Moreover, multivariate and pathway analyses were conducted for the different metabolites. The results showed that the heat stress caused changes in energy metabolism, amino acid metabolism, osmotic regulation, carbohydrate metabolism and lipid metabolism through different metabolic pathways. These results are consistent with the significant changes of oxygen consumption rate and ammonia excretion rate. The present study contributes to the understanding of the impacts of heat stress on intertidal bivalves and elucidates the relationship between individual-level responses and underlying molecular metabolic dynamics.
Highlights
Temperature is one of the more prominent abiotic factors that influences the physiological metabolism of animals and determines the ecological niche of a species (Pörtner et al, 2006; Pörtner, 2010; Ezgeta-Balić et al, 2011)
Metabolic rates After the temperature was increased to 24 C, the oxygen consumption rate of S. subcrenata decreased for 2 h, followed by a significant increase at 24 h and 48 h
The oxygen consumption and ammonia excretion rates were determined during stress caused by different elevated temperatures in S. subcrenata
Summary
Temperature is one of the more prominent abiotic factors that influences the physiological metabolism of animals and determines the ecological niche of a species (Pörtner et al, 2006; Pörtner, 2010; Ezgeta-Balić et al, 2011). In response to environmental changes, organisms typically adjust their metabolic physiology to adapt to new energy requirements (Cheung & Lam, 1995; Lagerspetz, 2006; Zhang et al, 2017) Metabolic response of Scapharca subcrenata to heat stress using GC/MS-based metabolomics. Intertidal bivalves frequently face extreme heat stress (Han et al, 2013), and form reliable models to investigate the adaptations to highly fluctuating environments (Davenport & Davenport, 2005; Wang et al, 2015). Studying the underlying metabolic alterations can help to understand the physiological changes that happen in bivalves in response to thermal stress
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