The Respiratory Rate of Gammarus chevreuxi in Relation to Differences in Salinity

Abstract

1. The rate of oxygen uptake was studied in the brackish water amphipod Gammarus chevreuxi in water of different salinities (25 per cent, sea water and sea water). The respiratory rate was found to be approximately 20 per cent, lower in sea water than in 25 per cent, sea water which is a concentration occurring in the natural habitat. Anaesthetised animals showed the same percentage decrease as unanaesthetised animals. 2. The change in oxygen consumption takes place immediately after the transfer and remains constant thereafter. It is completely reversible. 3. A comparison with the unanaesthetised respiratory rates of the related freshwater species G. pulex and marine G. marinus shows that the rate of oxygen consumption of the brackish water form G. chevreuxi in 25 per cent, sea water lies between the two others.