Comparability of Cartesian Diver, Gilson, Warburg and Winkler methods of measuring the respiratory rates of aquatic invertebrates in ecological studies.

Comparison of Cartesian Diver-Winkler measurements of respiratory rates in larvae of the damselfly Pyrrhosoma nymphula, and Cartesian Diver-Gilson comparisons in the snail Potamopyrgus jenkinsi are descibed. Measurements of oxygen uptake using these different methods do not differ significantly for the same species of animal at the same temperature. Published data likewise suggest that Warburg and Winkler measurements can give similar results.All these methods, therefore, appear to be equally suitable for ecological work, providing they are used carefully and with a sound knowledge of the biology of the animal under investigation.