Lisandrina Mari, a visiting PhD student from UMR CARRTEL - INRA, Université Savoie Mt Blanc will present her research:
In ectotherms, temperature is a key parameter influencing numerous biological traits. It is well known that modifications in environmental temperature are correlated with changes in metabolism and oxygen consumption, which in turn affect the oxidative balance of the organism. However, while the relationship between temperature, oxidative status and life history traits has been raising interest in some model organisms, such information has rarely been documented in non model organisms, in particular in wild populations.
The arctic charr (Salvelinus alpinus) is a cold-water-adapted and highly stenothermic salmonid that is widely distributed in subarctic regions. In alpine and peri-alpine lakes, the charr lives at the Southern edge of its native range and seems highly vulnerable to climate change as early life stages are known to be especially sensitive to temperature increase. Moreover, charr eggs and juveniles are particularly exposed to an array of environmental pressures such as pollutants or fine sediments that temperature might interact with.
In this study, we use a common garden approach to i) investigate the hypothesis of local adaptation of the species to thermal habitat, ii) assess the adaptive potential of populations, iii) study how temperature might modulate the impacts of other common stressors in freshwater environments.
We compare four arctic charr populations originating from thermally contrasted environments by rearing embryos at an optimum (5°C) or stressful (8.5°C) temperature and exposing them to several sediment loads. We examine adaptive differences at the population and individual levels in life history traits and physiological traits at the stages of hatching and emergence. The results are then discussed in relation to ecophysiological trade-offs hypotheses between the traits studied.