Just like terrestrial animals, marine life needs oxygen to live. Oxygen, which is a gas dissolves in water and therefore the oxygen in the water is commonly referred to as dissolved oxygen. Surface water dissolved oxygen levels are affected by both point or non-point pollution.

Point discharges which contain microbes that are high in oxygen demand create a dissolved oxygen sag killing the aquatic species in the water. Non point discharges, commonly known as run-off, which contain nutrients also lead to low dissolved oxygen conditions.

The nutrients, such as fertilizer, stimulate the growth of microbes in the water which use up the dissolved oxygen leaving little left for other life forms such as fish. Although reoxygenation occurs as surface water takes up oxygen from the atmosphere, this process takes too long to prevent fish kills in low dissolved oxygen water.

The best practices for reducing low dissolved oxygen conditions are to prevent discharges that contain oxygen consuming microbes or to artificially infuse dissolved oxygen into the water through mechanical aerators.

Learn more about YSI's Dissolved Oxygen Instruments and accessories:
YSI 550 Dissolved Oxygen Instrument
Dissolved Oxygen Accessories
Handheld Field Instruments
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