Hach Application Note: LDO Sensors, “Optical Dissolved Oxygen Measurements in Power and Boiler Applications.” (DOC043.52.30333) ...

However, fish have it much harder. To breathe, fish have to pull out molecules of oxygen dissolved in water using their gills, according to the Iowa Department of Natural Resources.

The amount of dissolved oxygen in a river is a matter of life or death for the plants and animals living within it, but this oxygen concentration varies drastically from one river to another ...

On several expeditions, the team’s dissolved oxygen sensors oddly suggested that the substance, rather than just being consumed by organisms, was actually, on the whole, being produced.