Does the Level of Turbidity Affect the Amount of Oxygen in Water?

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Turbidity can impact the level of dissolved oxygen in water in multiple ways. Increased light absorbency by turbid water can lead to increased water temperatures and decreased oxygen levels. The contents of the particles causing turbidity can also lead to a decrease in dissolved oxygen levels. Soil particles with excess nutrients can lead to algal blooms. The decomposition of these algal blooms and other organic compounds associated with turbidity causing particles leads to decreased levels of oxygen.

What is Turbidity?

• Turbidity describes how murky or cloudy water is. Water containing high levels of suspended particles is referred to as being very turbid.

Does Turbidity Affect Oxygen Levels in Water?

• Turbidity can impact dissolved oxygen levels in multiple ways through its light absorbing qualities and the chemical nature of the particles causing the turbidity.

Turbidity and Light Absorbtion

• Turbidity causing particles absorb lots of the sun's rays. When these rays are absorbed by a dark colored particle, energy is released as heat in much the same way that asphalt gets hot on sunny days. Due to this light absorbing property, turbid water it heated more rapidly by the sun than clearer water. As it warms, water loses its ability to hold dissolved oxygen; therefore turbidity can lead to a decrease in oxygen levels by its impact on water temperature.

Turbidity and Nutrients

• Turbidity is often caused by tiny soil particles that have washed into a waterbody from the land. These particles can contain nutrients that, when combined with water and sunlight, cause explosive growth of algae. When this algae dies and decomposes. The decomposition of algae involves a biological process that uses up significant quantities of oxygen. In this way, turbidity can cause lower levels of dissolved oxygen in water by causing algal blooms. This particular process is largely responsible for the enormous "dead-zones" found in many of our oceans.

Turbidity and Biological Oxygen Demand

• The various substances making up turbidity causing particles can have a high biological oxygen demand (BOD), which is a measure of the amount of oxygen used to decompose a substance. Increased turbidity is therefore associated with increased BOD and decreased