Fig. 7From: Non-invasive quantification of cardiac stroke volume in the edible crab Cancer pagurusStroke volume proxy of C. pagurus over time under different levels of water PO2. The cardiac stroke volume was approximated from signal peak integrals of IR-PPG recordings (cf. Figure 4) at 12 °C water temperature. Values were averaged over the last 6 h before switching to hypoxic conditions to represent controls and then transformed to a log2 scale. After at least 15 h of normoxic control, water PO2 was reduced to 15% air saturation by adding N2 gas. Hypoxic conditions were maintained for 6 h, after which the aeration was returned to ambient air. a and b are two runs on animal 1, separated by one week of recovery; c = animal 2; d = animal 3Back to article page