Oxygen Consumption of Mayfly Nymphs in Relation to Available Oxygen

Abstract

LITTLE is known of the reasons why freshwater animals are confined to certain habitats, or of the effects of their particular environments on the metabolism of the animals. The first steps in a study of these questions were reported in NATURE, 130, 277 (1932). It has been shown that certain animals living in swift streams have a higher oxygen consumption and rate of heart beat than nearly related animals living in still waters, and that they are less resistant to water lacking oxygen^1,2,3. The next step has been to study the oxygen consumption of such animals in terms of the available oxygen, and we have confined ourselves to mayfly nymphs. We have used Baëtis scambus and Baëtis sp. (the latter is one third the weight of the former) from a swift stream, Leptophlebia vespertina from Lake Windermere, Cloëon dipterum from a pond, and Ephemera vulgata living in mud in a pond. Our results are summarized in Fig. 1, in which the vertical line at an oxygen concentration of 7.9 c.c. per litre marks the oxygen content of water in equilibrium with the atmosphere at the temperature of the experiments, namely, 10°.