Oxidative stress biomarkers in the Mediterranean pond turtle ( Mauremys leprosa ) reveal contrasted aquatic environments in Southern France
Résumé
Increasing anthropogenic activities, like agricultural practices, constitute the main causes of the loss of
water quality and disruption of freshwater ecosystems. High concentrations of pesticides, as shown
under experimental conditions, can indeed impact freshwater animals. In Southern France, especially in
the Pyrenees-Orientales department, because agricultural activities are mainly based on fruit crops and
vineyards, glyphosate and AMPA were detected in some watercourses. Thereby we investigated the effects
of degraded waters on the physiology of the endemic endangered freshwater species, namely the
Mediterranean pond turtle Mauremys leprosa, in contrasted environments along the same rivers on the
one hand and between different rivers on the other. We measured the activity and gene expression of
two enzymes involved in the oxidative detoxification processes, namely the Catalase and the Superoxide
dismutase. We showed significant variations in the Catalase gene expression and activity within turtles
of the Fosseille River depending of their location, i.e. upstream or downstream of the wastewater
treatment plants (WTP). Because agricultural environments are similar all along this river, they can no be
longer considered as the unique source of turtle stress. The processed waters discharged by the WTP,