Fig. 8. Comparison of tissue-specific (solid line, NADH fluorescence intensity of the limb muscles; this study) and whole-animal (dotted line, lactate content; dashed line, rate of oxygen consumption) responses of haemoglobin (Hb)-poor (A) and Hb-rich Daphnia magna (B) to different ambient oxygen partial pressures (P_O2amb). Lactate determination was performed using animals 1.7–2.0 mm long incubated at different values of P_O2amb for 1 h at 22°C (Usuki and Yamagushi, 1979). The rate of oxygen consumption (dashed line) was measured in animals 2.5 mm long at 20°C using a closed respirometry system (Kobayashi and Hoshi, 1984).