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DISSOLVED OXYGEN (DO)
What is it?
Why test for it?
Waters with consistently high levels of DO are considered healthy and stable aquatic ecosystems that can support a variety of life.
Low DO levels indicate a demand on the oxygen in a water body and may result from several scenarios.
What affects dissolved oxygen levels?
Increased suspended solids can affect dissolved oxygen by causing water to become warmer and lessening its ability to hold oxygen. Cooler water has a higher potential level of DO. DO levels also may be affected by the decomposition of plants. Aerobic bacteria consume oxygen as they break down dead organic material. Plants also affect the amount of DO through respiration. When photosynthesis stops, plants and animals continue to respire and consume oxygen. Just before dawn, DO falls to its lowest level.
How can we improve the DO capacity of a surface water?
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