Die wirkung der sauerstoffspannung auf die druckresistenz einiger mariner wirbelloser

Variations in oxygen tension exert a considerable influence on the resistance of invertebrates to high hydrostatic pressure. Pressure resistance of whole animals (Idotea baltica, Cyprina islandica) and of isolated tissues (gill tissues of Cyprina islandica and Mytilus edulis) is higher in a medium not fully air saturated; it decreases with increasing oxygen tension to about air saturation or higher. In some species, pressure resistance decreases when dissolved oxygen is almost absent. Oxygen tension influences pressure resistance not only during exposure to increased pressure; our experiments revealed that pressure resistance increases in isolated tissues kept under oxygen deficiency prior to the experiment. Lactic acid, a result of anaerobic glycolysis, increases cellular pressure resistance only if its presence is combined with decreased pH values. Metabolic inhibition with cyanide does not increase pressure resistance. It is suggested that the primary reasons for lowered pressure resistance at saturation or higher oxygen levels are oxydation and inhibition of sensitive SH-enzymes under pressure. Decrease of pressure resistance at extreme degrees of oxygen deficiency may be due to insufficient rates of ATP synthesis. According to Marsland (1957), ATP is required for maintenance of protoplasmic gel structures. Correlations between pressure resistance and oxygen tension are of special importance in deep-sea animals, which often have to face reduced oxygen contents in their ambient medium.