The Gooseneck Barnacle (Pollicipes pollicipes) as a candidate sentinel species for coastal contamination.

The assessment of toxic effects caused by complex mixtures of contaminants in the marine environment requires previous validation of toxicological criteria, which may include biomarker end points with distinct biological meanings. This is the case of oxidative stress/phase II detoxification (glutathione-S-transferases activity), oxidative damage (thiobarbituric acid reactive substances), and neurotransmission (cholinesterase activity), which are likely to be affected after toxic insults by common marine pollutants. The main purpose of the present study was to assess potential biological alterations in the mollusk species Pollicipes pollicipes (gooseneck barnacle) caused by human contamination and seasonality, during a period of 1 year, in three different areas of the North Atlantic shore of Portugal. Our results indicate that fluctuations of the mentioned biomarkers were strongly related to seasonality, but they may also suffer influence by the already documented patterns of chemical contamination. Organisms collected in contaminated sampling sites (urban areas and oil refinery) showed greater levels of metabolic enzymes and increased levels of lipid peroxidation. These alterations were more evident during the summer, and, in some cases, spring months, suggesting an association between the presence of chemical stressors and temperature-dependent seasonal physiological fluctuations, which contribute to the modulation of the toxic response. In general terms, P. pollicipes was shown to be a promising organism in coastal biomonitoring programs, with an adequate sensitivity toward contamination and/or seasonal fluctuations. However, it is of the utmost importance to consider seasonal fluctuations in physiological parameters that modulate the toxic response. These factors can ultimately compromise the development and interpretation of data from marine biomonitoring programs if a thorough characterization of biological responses is not previously performed.