Fig. 3. White muscle PCr (A) and pH_i (B) in carp exposed to normoxia and hypoxia for up to 3 h at 15°C (squares) and 25°C (circles). Phosphocreatine levels are normalized to the sum of PCr and P_i, and expressed relative to normoxic controls. NMR data were collected at the fishes' acclimation temperature and for each time point an average consisting of 256 spectra gathered over 5 min is shown. The black horizontal bar immediately above the x-axis indicates the period of hypoxia exposure (P_O2=20 Torr). Each point represents mean ± s.e.m. N=7–10 for each point.