Objective: The aim of the project is to understand the role of the animal’s physiology in its decision to stay in a warm environment or move to a cooler one. The link between physiology and behaviour is crucial for understanding the movement of coastal and estuarine fish in the face of increasingly intense and frequent heat waves (Frölicher, et al. 2018). The project will be carried out on a model of high economic importance and food resource for human: the European sea bass.
Background: The energy metabolism of ectothermic animals varies with the temperature of their environment. Extreme temperature fluctuations such as heat waves are predicted to negatively affect many aspects of ectothermic metabolism, including an increase in the need for nutrient resources and oxygen, and a decrease in their ability to produce cellular energy, Adenosine TriPhosphate -ATP (Blier, et al. 2013). An ectothermic organism exposed to heat requires more ATP to provide chemical energy for cellular processes such as protein synthesis, cell division, osmoregulation or even cardiac contractions, the rates of which increase with temperature (Schulte 2015). There is particular uncertainty about the role of optimal temperature for mitochondrial ATP synthesis in the thermal preference of aquatic ectotherms. At warm temperatures, mitochondria dysfunction, their inner membrane becomes leaky and energy is dissipated in proton leakage in place of the ATP production, which can lead to ATP limitation for proper cellular function, loss of consciousness of the animal and death. Before becoming ATP-limited, the animal may engage in thermoregulatory behaviour, i.e. move towards a thermally favourable area. The thermoregulatory behaviour of a mobile animal, such as a fish, is typically measured by its choice to spend the majority of its time in one thermal environment rather than another. It is therefore possible that an organism with mitochondria whose optimal temperature is high prefers to stay in relatively warm water compared with an animal whose mitochondria perform better at lower temperatures; the latter will prefer to flee to a cooler environment.
Hypothesis: the thermal preference of juvenile sea bass can be explained by the thermal optimum of their mitochondria. Individuals that spend more time in warm water are able to produce a lot of ATP at higher temperatures than individuals that prefer cooler water
Compensation:
Erasmus + grant available depending on eligibility criteria of your home university
Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Education and Culture Executive Agency (EACEA). Neither the European Union nor EACEA can be held responsible for them.
