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3A - Biomarker/Biomonitoring (TU8/2) An early warning in situ estuarine toxicity test using the shrimp Crangon crangon: combining biomarkers and ecologically relevant endpoints. Menezes, Salomé 1, Guilhermino, Lucia2, Soares, Amadeu1, Peck, Mika1, 1 Universidade de Aveiro, Campus Universitário de Santiago, Aveiro, Portugal2 Universidade do Porto, CIIMAR, Porto, Portugal ABSTRACT- An in situ estuarine toxicity test was developed using the euryhaline shrimp Crangon crangon to measure impacts on the molecular biomarkers acetylcholinesterase (AChE), glutathione S-transferase (GST) and lactate dehydrogenase (LDH). Impacts at the biomarker level provide an early indication of contaminant type and exposure and an ecologically relevant endpoint (feeding inhibition) provides an indication of impact at the population level. In situ deployment in estuarine environments means organisms are exposed to large natural fluctuations of potential stressors. It is vital that background variability of biomarkers in response to temperature and salinity be quantified to avoid confounding contaminant induced responses, for example, a slight increase in LDH was observed under constant salinity of 10 PSU that may be indicative of increased energy costs associated with the higher osmoregulatory work required to maintain a hypertonic haemolymph. Least stress was observed under exposure to a diurnally variable saline gradient from 5 PSU to 35 PSU; normal under estuarine conditions. Feeding was assessed using a novel method by encapsulating homogenised Artemia salinia in an alginate matrix. In addition, as a number of studies using in situ toxicity testing have concluded that factors other than contaminants may have resulted in false positives in field tests there is an urgent need for reliable controls. To address this, an in situ control chamber is under development for deployment alongside in situ chambers in the field. The in situ control chamber uses membranes to exclude contaminants from the chamber leaving the control shrimp exposed only to non-contaminant stressors such as temperature, thus providing a pertinent control. Key words: in situ, Estuarine, biomonitoring, shrimp |
