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The case for reporting PO2 (partial pressure of oxygen), in addition to DO (dissolved oxygen), in studies of aquatic systems
- Ultsch, Gordon R., Nordlie, Frank G.
- Comparative biochemistry and physiology 2019 v.235 pp. 66-68
- dissolved oxygen, oxygen, oxygen partial pressure
- In this essay, we question the sole use of mg/L (ppm) and the term DO (dissolved oxygen) when referring to oxygen supply in water, and discuss reasons for also reporting the partial pressure of oxygen (PO2). Oxygen moves from water into organisms by diffusion only, and the rate and direction of diffusion is solely dependent upon partial pressure gradients, not concentration gradients. However, the amount of oxygen moved into an organism is both a function of DO and PO2. Therefore, to have physiological and ecological relevance, the presence of oxygen in water, when reported as DO, should also include PO2.