Metabolic responses to food and temperature in deep-sea isopods, Bathynomus doederleini

Abstract

Metabolic rate, the amount of energy consumed per unit of time, for an organism to sustain life, is influenced by both intrinsic and extrinsic factors. Despite similarities among living organisms across the various domains of life, those adapted to deep-sea environments exhibit notable differences from those in shallower waters, even when accounting for size and temperature. However, as deep-sea organisms are infrequently kept in captivity for prolonged periods, investigations into their potential metabolic responses to food and temperature have not been conducted. In this study, we demonstrate the impact of food (specific dynamic action: SDA) and temperature (Q10) on the metabolic rate of the deep-sea isopod, Bathynomus doederleini. There were positive correlations between SDA parameters (peak rate, time to peak, duration, and factorial scope) and meal size in deep-sea organisms. The postprandial metabolic rate, at a meal constituting 45% of wet body weight, increased by approximately 6.5-fold, and the duration was 20 days. Within the temperature range of their natural habitat (15–6 °C), the overall Q10 was 2.36, indicating that a 10 °C increase would lead to a 2.4-fold increase in resting metabolic rate. This species could survive for a year on a few grams of whale blubber at a water temperature of 10.5 °C. This information is crucial to understand the metabolic strategies and consequences of adaptation to deep-sea environments.