Meade 1994 J Exp Zool
|Meade ME, Doeller JE, Kraus DW, Watts SA (1994) Heat and oxygen flux as a function of environmental pO2 in juvenile Australian crayfish, Cherax quadricarinatus. J Exp Zool 270:460-6.|
Meade ME, Doeller JE, Kraus DW, Watts SA (1994) J Exp Zool
Abstract: Oxygen and heat flux of the juvenile Australian red claw crayfish, Cherax quadricarinatus, were measured in parallel respirometry and calorimetry systems at 28 °C at varying levels of environmental po2. Juvenile crayfish maintained an average oxygen flux of 5.0 ± 0.4 (SEM) pmol O2/(s*mg fresh weight) over the po2 range from 20.7 to 5 kPa. At approximately 4 kPa po2, oxygen flux decreased, conforming to decreasing oxygen tensions. Juvenile crayfish maintained an average heat flux of −2.2 ± 0.2 μW/mg fresh weight when exposed to 100 and 50% air saturated conditions (18.1 to 20.7 and 7.8 to 10.4kPa po2, respectively). The ratio of the amount of heat dissipated per oxygen consumed, called the calorimetric/respirometric (CR) ratio, at 100 and 50% air saturated conditions averaged −440 kJ/mol O2. When crayfish were exposed to 25% air saturated conditions (2.5 to 5.2 kPa po2), heat flux decreased initially to −1.1 ± 0.4 μW/mg fresh weight. Within 4 hr, however, heat flux returned to normoxic values. When crayfish were exposed to anoxic conditions, heat flux decreased to zero. Most juvenile crayfish did not survive short-term (1–2 hr) anoxic stress. These data suggest that juvenile C. quadricarinatus are excellent oxygen regulators over a wide range of environmental po2. These data indicate also that juvenile C. quadricarinatus can compensate metabolically, possibly via aerobic and/or anaerobic adjustments, in order to maintain metabolic rate at critically low po2. Last, this crayfish appears limited in its ability to utilize anaerobic pathways to maintain metabolic rate in anoxic Environments.
• O2k-Network Lab: US AL Birmingham Kraus DW
Labels: MiParea: Respiration, Comparative MiP;environmental MiP, Developmental biology
Stress:Ischemia-reperfusion Organism: Crustaceans