Classic methods and controls of biota parameters of fresh reservoirs have a row of substantial defects to that belong: systematic uncharacter of control of informatively important parameters; subzero exactness of parameters control; large volume of hand operations; necessity of knowledge of mathematical bases of method; bad interpretation of results; need to use support staff. The shortcomings of known methods can be corrected with an automated way of obtaining and processing the informative parameters of fresh water biota. A structural scheme of the process of obtaining the selected parameters of the biota and the preferential algorithm of their processing have been developed. It is shown that the most convenient for collecting mass material about the content of dissolved oxygen in the reservoir is the optical method. Comparison of synchronous measurements by optical and electrochemical sensors showed a significant underestimation of the dissolved oxygen content by an electrochemical sensor compared to the optical one. The optical method of measuring the content of oxygen dissolved in water is based on finding the time and intensity of fluorescence of the sensitive membrane by empirical ratio. Molecules of dissolved oxygen reduce the time and the intensity of membrane fluorescence, created from carefully selected chemical elements. An absolute concentration can be determined after linearization and thermocompensation, which is performed with the help of a built-in water temperature sensor
biota, oxygen, optical sensor, fresh reservoir, ecological state