- Conducting the test: A dissolved oxygen test kit is used. A sample of the river water and a solution, which causes the water to change color. This color is then compared to the color bar in the test kit to determine the DO level.
- Testing: The amount of oxygen in the water available to aquatic organisms for respiration.
- Importance: Dissolved oxygen is needed for nearly all aquatic life to breath and survive. If an area is too low in DO, then it becomes a dead zone, which cannot sustain any life.
- Natural Occurrence: Aquatic plants that perform photosynthesis produce the dissolved oxygen in a water body. Oxygen is also absorbed in water through direct diffusion and surface-water agitation. In diffusion, oxygen in high concentrations in the air naturally moves to the water, which has a lower concentration of oxygen. In surface-water agitation, air and water are mixed when winds or the flow of the water create disturbances on the surface.
- Human Impact: Any organic matter introduced into the river will be broken down by decomposers who use up the dissolved oxygen. This organic matter is often introduced by humans through sources such as sewage pipes (see image below). Decomposers flock to the organic matter to break it down, and while carrying out the process they consume some of the available oxygen. This leaves less DO for the aquatic organisms in the area.
- Data: Our tests revealed an average DO concentration of 11.67 mg/L, which translates into a Q-Value of 87/100. This means that the water quality in this area is very good in terms of the amount of dissolved oxygen.
- Explanation of Results: These results indicate that there is enough oxygen in the water to support lots of aquatic life. It also means that there has likely not been an algal bloom recently in this portion of the river. Little human-caused disruption of the river is a leading factor in the high water quality in terms of DO.