Metabolic response of the cannonball jellyfish Stomolophus meleagris upon short-term exposure to thermal stress

Abstract

Jellyfish are non-model organisms that have brought the scientific community's attention over the last decades since the frequency and intensity of these species blooms around the world have increased significantly. The occurrence of blooms has been hypothesized due to the rise in seawater temperature associated with climate change. This fact has promoted an increased interest in studying jellyfish metabolic responses to face thermal stress and maintain cell homeostasis. In this study, the response of the cannonball jellyfish Stomolophus meleagris to short-term exposure to different temperatures was evaluated. The survival and respiratory rates, and the concentration of glucose, L-lactate, glycogen, ATP, and total soluble protein in the umbrella of adult jellyfish were measured. Low survival rates at extreme temperatures (18 and 33 °C) and an increase in the jellyfish respiratory rates were observed as seawater temperature raised. Rapid changes were detected in energy substrates such as glucose and glycogen that significantly varied at extreme temperatures and longer exposure periods. L-lactate levels increased after 2 h of exposure, and then remained steady at longer times of exposure. Soluble protein concentration decreased significantly in jellyfish exposed to extreme temperatures, and ATP increased after exposure to non-optimal temperatures (18, 28, and 33 °C). These results suggest that S. meleagris faces temperature changes through rapid metabolic responses that use energetic reserves, activate anaerobic metabolism, and display a remarkable ability to synthesize ATP and maintain energy, even at long exposure.