Measuring the content of oxygen dissolved in a freshwater reservoir

For the life of fish and other aquatic animals, the oxygen dissolved in water is particularly important. Oxygen partially penetrates into water from the atmosphere, partially released in the reservoir itself as a result of the livelihoods of plant organisms. By means of chlorophyll, green plants extracted from carbon dioxide needed to construct a living matter of carbon, allocating oxygen in the surrounding space. This process of photosynthesis proceeds due to the energy of sunlight only in the light time of day. The penetration of oxygen in the atmosphere contributes to wind, flow, precipitation, sharp changes in temperature and other reasons that increase the mixing of water layers. In reservoirs, strongly contaminated organic substances, the water in addition to the rich salts of sulfuric acid (sulfates) may appear poisonous for fish and other aqueous animals gaz – hydrogen sulfide. It occurs only in the absence of oxygen with the participation of special bacteria. Carbon dioxide is accumulated as a result of breathing aquatic organisms, and most importantly - as a result of oxidation of organic matter. Therefore, the excess of carbon dioxide indicates a significant contamination of reservoirs by organic substances.