D.O
D.O means dissolved oxygen. Dissolved oxygen is oxygen dissolved in water. Oxygen gets in the water from surrounding air, forcing air into water that has fallen over falls, rapids and a waste product of photosynthesis. If the water gets to warm there may be to little oxygen in the water. When there is too much bacteria or aquatic creatures such as fish they can overpopulate by using too much D.O. Also if the water becomes to warm, even if 100% saturated, 02 levels may be suboptimal for many species of trout. Why is D.O important? It is important because earth bound animals and aquatic organisms need oxygen to breath. If D.O levels drop below 3.0 parts per million, the rough fish die. D.O can be one of the best indicators of a water ecosystem and the health of it. D.O can range from 0-18 ppm, most natural water systems use 5-6 ppm. Did you know dissolved oxygen could be measured in two different ways? To measure in meters you measure the partial pressure of the oxygen in the water. To use a field kit you add a solution that treats the water sample from the water. If the dissolved oxygen increases aquatic insects cannot tolerate decreases from dissolved oxygen. When this happens pollution-tolerant worms and larvae replace the pollution-intolerant organisms. When runoffs drain into rivers and streams the rain drains oil, gasoline and salt can pollute the water. Certain bacteria and water plants such as duckweed and water hyacinths, can clean up the polluted water. Dissolved oxygen decreases which means a decrease in dissolved oxygen levels is usually an indication of an influx of some type of organic pollutant. Decreases from dissolved oxygen can also change types and numbers of aquatic insects that live in the water. Did you know D.O levels change according to the time of day, weather and it's temperature? D.O levels are announced in percent saturation. For example D.O concentrations are calculated and the percent saturation will undo the effect the temperature. What does parts per million mean? Parts per million means a part in 1,000,000 (million) a mg/liter is equal to parts per million.