pH-bicarbonate (Davenport) diagram demonstrating the time course of acid–base compensation. Blood acid–base status was determined along the experimental period of 168 h for animals exposed to control (pH 8.1), intermediate (pH 7.7) and low (pH 7.3) conditions. For clarity reasons the intermediate pH (A) and low pH (B) treatments are presented in two separate graphs, including control acid–base conditions along the incubation period of 168 h. The non-bicarbonate buffer line for Sepioteuthis lessoniana is indicated by a grey dashed line and was adopted from Lykkeboe and Johansen . The solid curved lines represent p CO2 isopleths. Numbers in brackets indicate sampling time points. Bars represent mean ± SE (n = 3 replicate tanks, with six biological replicates per time point and treatment).