|The effect of environmental oxygen concentration on the rate of oxygen consumption of the Polychaete Sthenelais boa (Johnston)|
Cosgrove, W.B.; Hajduk, S.L. (1980). The effect of environmental oxygen concentration on the rate of oxygen consumption of the Polychaete Sthenelais boa (Johnston). Cah. Biol. Mar. 21(2): 123-133
In: Cahiers de Biologie Marine. Station Biologique de Roscoff: Paris. ISSN 0007-9723, more
|Authors|| || Top |
- Cosgrove, W.B.
- Hajduk, S.L.
The oxygen consumption, V-02 , of S. boa has been calculated from continuous recordings of the partial pressure of oxygen in a sealed respiration chamber containing a single individual and the partial pressure of oxygen in the coelom, P-02 (I), at several environmental partial pressures of oxygen, P-02 (E), has been measured with a micro-O-2 electrode inserted into the coelomic cavity. All of the 19 individuals studied were strict oxyconformers at least up to P-02 (E) of 159 torr; at that partial pressure, V-02 's were higher than values reported for other species of annelids of comparable size (0.99 to 3.31 g body weight). Mean P-02 (I) was 33 torr at P-02 (E) of 159 torr, decreasing to zero at a predicted mean P-02 (E) of 6.2 torr. No evidence of the incurring of oxygen debts was found. The strict oxyconformity indicates that oxygen activity in the tissues is insufficient to saturate the terminal oxidases over the whole range of environmental partial pressures oxygen encountered under natural conditions. The authors propose that this insufficiency results from the combination of a respiratory surface which is inefficient in oxygen exchange and a circulatory system which is poorly developed and lacks hemoglobin to assist in the transport of oxygen. The myoglobin-like pigment surrounding the central nervous system may provide this structure with an improved supply of oxygen. The strict oxyconformity which prevails in the resting individual requires that the extra energy expended during activity be supplied by anaerobic metabolic processes.