The problem of measuring the heat production of small aquatic animals

Abstract

This paper considers the construction of a very sensitive and rapidly responding flow-through microcalorimeter to be used, for instance, for studying the effects of environmental circumstances on the metabolic rate of small aquatic organisms. The measurement principle, which allows random fluctuations of the inflow temperature, is based on the repetitive determination of the temperature differences between inflow and outflow of a small measuring vessel. Temperature differences between inflow and outflow are recorded at a rate of several measurements per second. In the design of the calorimeter, special attention is paid to the temperature homogenisation in the measuring vessel. The temperature data are used to calculate the heat dissipation according to an algorithm as derived in this paper. In a numerical model, the performance of the design is tested in order to derive optimal parameter settings for measuring frequency in relation to measuring accuracy.