Haemolymph oxygen transport and acid-base status in Glyptonotus antarcticus Eights

Haemolymph samples were withdrawn from routinely active male intermoult Glyptonotus held at 0 +/- 0.5 degrees C, and analysed for blood-gas and acid-base variables. In both the arterialised (a) and venous (v) haemolymph, over 50% of the oxygen was transported as dissolved oxygen at PaO2 and PvO(2) levels of 12.0 +/- 1.15 and 7.70 +/- 1.89 kPa, respectively. The maximum oxygen-carrying capacity of the haemocyanin (C(max)HcO(2)) was relatively low at 0.19 +/- 0.05 mmol 1(-1) accompanied by relatively low protein and [Cu2+] levels indicating low circulating haemocyanin concentrations. Arterialised haemolymph had a mean pH of 7.88 +/- 0.02(6) at a PCO2 of 0.12 +/- 0.01(6) kPa and a bicarbonate level of 12.95 +/- 0.80(6) mequiv 1(-1) with small differences in PCO2 and pH between arterial and venous haemolymph. The non-bicarbonate buffering capacity of Glyptonotus haemolymph was low at -2.0 mequiv 1(-1) HCO3- pH unit(-1). Haemolymph [L-lactate] and [D-glucose] levels were similar at < 1 mmol 1(-1) in animals held in the laboratory and those sampled in Antarctica. The blood-gas and acid-base status of Glyptonotus haemolymph may be a reflection of the low and stable temperatures experienced by this Antarctic crustacean.