Temperature-dependent physiological response of Carcinus maenas exposed to copper

The effect of temperature on the heart rate (fH) of Carcinus maenas exposed to a sublethal nominal concentration (0.5 mg l−1) of copper is reported. Adult, intermoult males (4 cm carapace width) were collected from Stavanger Fjord (Norway) in August (seawater TEMPERATURE=17 °C) and maintained in the laboratory (fed ad libitum) at 5, 15 and 25 °C for 7 days. Following this holding period, crabs were exposed to waterborne copper at the same temperature. After 3 days of exposure, individual fH was measured using the non-invasive Computer Aided Physiological MONitoring system (CAPMON) method. Copper-exposed individuals demonstrated significantly increased fH compared with controls at 5 and 25 °C (P<0.01). It is inferred that physiological function in C. maenas may be more vulnerable to copper contamination at seasonal temperature extremes (5 and 25 °C) than at the ‘standardʹ test temperature (15 °C). Additionally, cardiac arrest observed at 5 °C is interpreted as a physiological response to limit copper uptake while the erratic fH in the 25 °C group reflected enhanced copper toxicity.