Oxygenation (environmental)

Environmental oxygenation can be important to the sustainability of a particular ecosystem. Insufficient oxygen (environmental hypoxia) may occur in bodies of water such as ponds and rivers, tending to suppress the presence of aerobic organisms such as fish. Deoxygenation increases the relative population of anaerobic organisms such as plants and some bacteria, resulting in fish kills and other adverse events. The net effect is to alter the balance of nature by increasing the concentration of anaerobic over aerobic species.

Oxygenation by water aeration can be part of the environmental remediation of a usually stagnant body of water. For example, Bubbly Creek in Chicago, Illinois, was hypoxic (deficient in oxygen) due to its use as an open sewer by Chicago's meat packing industry but has been oxygenated by introducing compressed air into its waters, increasing the fish population. A similar technique has previously been used in the Thames.

Dissolved oxygen (DO) is measured in standard solution units such as millilitres O₂ per liter (ml/L), millimoles O₂ per liter (mmol/L), milligrams O₂ per liter (mg/L) and moles O₂ per cubic meter (mol/mm³). For example, in freshwater under atmospheric pressure at 20 °C, O₂ saturation is 9.1 mg/L.

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