The influence of seasonality on biomarker responses in Mytilus edulis

Abstract

The utility of some biomarkers in environmental monitoring may be limited due to the lack of knowledge that exists on how they respond to extrinsic abiotic and intrinsic biotic factors. During the present study we investigated the seasonal responses of three biomarkers, Neutral Red Retention, clearance/filtration rate and heart rate in the common blue mussel Mytilus edulis located in the Exe Estuary, UK during September 2006-September 2007. During the current study, a significant decrease in feeding rate was observed in mussels during June, July and August 2007, coinciding with the period following spawning when the mussels lay down nutrient reserves. Heart rate also increased between April and September 2007 and corresponded with times when mussels were spawning and laying down nutrient reserves. By integrating the individual biomarker responses into a Biomarker Response Index (BRI) we were able to identify times of the year when environmental impact was highest and hence when the timing of monitoring programmes using biomarkers should be carried out. For many years the lack of knowledge of normal physiological ranges of biomarkers has impeded their applied use, however by integrating biomarker responses into the BRI and creating an index of health, we have shown that we can limit the natural variability of individual responses; and thus we are better able to make informed judgements on the overall health status of these populations of mussels.

Phase I and II biotransformation enzymes and polycyclic aromatic hydrocarbons in the Mediterranean mussel (Mytilus galloprovincialis, Lamarck, 1819) collected in front of an oil refinery

“…The observed outlier at 15 km of distance might probably reflect the biological variability of responses to environmental stressors of natural populations (native mussels) as in the present study. The potential exposure to other classes of environmental pollutants as PCBs or other alogenated compounds able to affect NADPH-cyt c red activity in mussels could not be also excluded (Nasci et al, 2002;Hagger et al, 2010). On the opposite, still regarding phase I enzymes, B(a)PMO activity did not change among sites except in specimens from HIS which resulted higher.…”

“…Nevertheless, to date most of field studies provide contradictory results despite the sensitivity of NADPH-cyt c red to PAHs and in particular B(a)P exposure has been already reported in several laboratory studies (Livingstone, 1988;Michel et al, 1993;Okay et al, 2000). Linking the exposure to PAHs with biomarker responses in the field is related to multi-factorial interaction of different environmental and physiological variables (Hagger et al, 2010). No changes in NADPH-cyt c red activity were observed in specimens of M. edulis collected along a PAH-gradient caused by an oil spill off the Galician coast (Solé et al, 1996).…”

Separate and combined effects of copper and freshwater on the biodiversity and functioning of fouling assemblages

“…Tolerance to copper has been reported to increase with the developmental stage of barnacles (bambang et al, 1995). There is also seasonal variation in the response of some organisms to pollution (due to reproductive status, availability of food and/or change in temperature) (Hagger et al, 2010) however the time difference between these two sampling dates may not explain the inconsistencies in this study. It is also important to note that indirect effects of the stressors may occur, modifying the assemblages' response.…”

Applications of biological tools or biomarkers in aquatic biota: A case study of the Tamar estuary, South West England

“…It is well established that studies which span multiple seasons are particularly important to establish robustness of biological tools (Bignell et al, 2008;Bocchetti et al, 2008;Garmendia et al, 2010;Geffard et al, 2002;Hagger et al, 2010). To use an example from the Tamar to illustrate the importance of seasonality -it is well established that marine mussels of the genus Mytilus show clear seasonal variation in a variety of biological responses as a result of their seasonal gametogenesis cycle (Dallas et al, unpublished data;Hagger et al, 2010;Banni et al, 2011).…”