Dissolved Oxygen

    Dissolved Oxygen

    Dissolved Oxygen 

    Definition: A measure of oxygen dissolved oxygen units and rangesmolecules dissolved in the water. These are not the bubbles in the water and are invisible to our eyes.

    Why we monitor dissolved oxygen: Dissolved oxygen is essential for aquatic organisms. This is what fish and macroinvertebrates breathe through their gills underwater. If values get too low then organisms can die.

    What influences dissolved oxygen: Water temperature has a large effect on dissolved oxygen. As water warms, the amount of dissolved oxygen water can hold decreases. Therefore, human actions that increase stream temperature (e.g. removing water or riparian trees that create shade) lead to lower dissolved oxygen levels. Aquatic plants also influence dissolved oxygen because the photosynthesis process releases oxygen into the water so dissolved oxygen concentrations often increase throughout a day. At night plants use oxygen but do not photosynthesize, so dissolved oxygen concentrations decrease until the sun comes up again.

    The State of Utah has set minimum dissolved oxygen concentrations to protect fish and other aquatic animals. In addition, different species and different activities require different concentrations of oxygen. You can find the water quality standards as part of the Utah Administrative Code R 317-2

    For more information on dissolved oxygen visit our Dissolved Oxygen page.

    For instructions on how to monitor dissolved oxygen select either the Chemets (Tier 1 method) or the LaMotte method above.