Would like some discussion on the chart. Not a DO expert but there must be other factors at work as our water is routinely over 80F and has 5 + ppm O2. Also if the chart is right and there are no other factors then most all the fish in 90 F water would be dead as 2 ppm is death range.
This is a good basic info source.
http://edis.ifas.ufl.edu/fa002 High Water Temperature
Warm water is much less capable of holding oxygen gas in solution than cool water. For example, water that is 90° F can only hold 7.4 mg/L DO at saturation, whereas water that is 45° F can hold 11.9 mg/L DO at saturation. This physical phenomenon puts the fish in double jeopardy because at high water temperatures their metabolic rates increase, hence their physiologic demand for oxygen increases.
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