The Respiratory Metabolism of Dendrostomum cymodoceae Edmonds (Sipunculoidea)

Abstract

The consumption of oxygen of Dendrostomum cymodoceae at 22'C in aerated sea-water varied from 4-5-5.5 μl/g (wet weight)/hr for adults to 20-31 μ/g/hr for juveniles. The production of carbon dioxide was 13-17 μ/g/hr (juveniles) and the R.Q. varied from 0.55 to 0.67 (juveniles). The rate of consunlption of oxygen decreased as the tension of the dissolved oxygen decreased. The oxygen combined with the pigment of the blood was 2.1 vols. of oxygen per 100 vols. of blood and the ratio of blood volume (ml) to total weight (g) of the animal was 0.47. D. cymodoceae was able to live under anaerobic conditions in sea-water for as long as 5 days and in paraffin oil for 4 days. The haemerythrin in the blood of animals kept under oil was found to be reduced after about 6 hr. Lactic acid was identified as one of the end-products of anaerobiosis. The concentration of lactic acid in the blood of animals living under anaerobic conditions increased after 60 hr from 7-12 to 46-61 μg/ml of blood. The ability to revert to anaerobiosis may have survival value for the species.