Fig. 8. Chart to show biphasic modelling for long duration dives during the first 15 s post surface for four tufted ducks. The smoothed V_O2 data (open circles) have been log-transformed. Least-squares regression is then performed using the linear and the biphasic regression lines. Phases 1 and 2 of the biphasic regression line can be seen with the point of inflection at 3.28 s post surface.