ESTIMATING THE PARAMETERS OF DISSOLVED-OXYGEN DYNAMICS IN SHALLOW PONDS

A modelling of the circadian evolution of dissolved oxygen dynamics in shallow homogeneous ponds, using a very simple and short-term mechanistic model and continuous measurements of dissolved oxygen, water temperature and light intensity, is presented. Two levels of results are obtained. First, a qualitative level providing information on the general behaviour of the model and its ability to fit the data. The point is to appreciate the suitability and the range of validity of the model, when a great number of data sets is available in various situations. Secondly, a quantitative level providing in situ daily values for pond respiration, oxygen transfer coefficient, initial slope and maximum of the photosynthesis versus light relationship. Such simple models, running on short periods and fitted on continuous measurements, should be considered as complementary tools for in situ investigations of aquatic ecosystems and for ecological model building.