Cold-water octocoral Viminella flagellum respiration rates during an acute Cu exposure

Herein we report the respiration rates (O2 consumption) of the cold-water coral Viminella flagellum exposed to acute Cu concentrations. In a lab experiment, sixty nubbins of V. flagellum were distributed in six aquaria of 8 L (ten nubbins per aquarium) of each Cu solution (0 (control); 60; 150; 250; 450 and 600 μg/L) for 96 h. After this period, four nubbins from each Cu treatment, selected randomly, were incubated individually for 6 h in glass chambers filled with ca. 110 mL of 0.2 μm pre-filtered seawater, with the respective Cu dilutions (4 chambers per Cu concentration). The incubation period was set to 6 h to record changes in O2 consumption without exposing corals to oxygen levels below 80 % (air saturation, a.s.). During the incubation period, dissolved O2 (μmol/L) depletion rates were recorded every 30 min and corrected by the corresponding rates/variations in chambers without corals. Coral respiration rates were normalized to the coral surface area and time. Results are presented by µmol of O2 consumption per m2 per h.