Influence of temperature rise on the recovery capacity of Mytilus galloprovincialis exposed to mercury pollution

Abstract

Several studies have described the impacts caused by metals on estuarine species, including mussels, but scarce information is available regarding their effects in a global warming context. Moreover, increased temperatures can not only affect the response oforganisms but their capacity to recover from pollution events. In this way, the present study aimed to understand the impact of temperature rise on the capacity of Mytilus galloprovincialis to recover their biochemical performance from pre-exposure to Hg. For this, mussels were exposed during 14days at 17°C in the absence or presence of Hg (17°C; 17°C Hg), after which mussels were exposed for an additional period of 28days at 21°C in the absence or presence of Hg (21°C; 21°C Hg) or kept for the same period at 17°C in the absence or presence of Hg (17°C; 17°C Hg), and biomarkers related to mussels’ metabolic and oxidative stress status were evaluated as well as Hg accumulation. Our findings revealed that regardless of temperature regime, organisms previously exposed to Hg followed by a 28days recovery period (absence of Hg) presented a significant decrease on the metal concentration. Furthermore, energy-related and oxidative stress markers in mussels recovering for 28days in the absence of Hg demonstrated no differences between mussels exposed to warming conditions (21°C) and control temperature (17°C), with a tendency to match control values (observed in mussels exposed the entire experiment to 17°C in the absence of Hg), indicating that temperature has no influence on mussels’ recovery capacity.