Tell me if this line of reasoning is correct: The partial pressure (PP) of oxygen in water which is saturated with air is the same as the partial pressure of the oxygen in the air around the water. Now, if I have a channel where cells are consuming oxygen, the PP is going to be going down over the length of the channel. Now, lets say I am measuring the partial pressure of the oxygen along the bottom of the channel (where the cells are) and I normalize these values against the inlet (saturated PP concentration) -- now lets say I have a model which gives me oxygen concentrations in terms of absolute concentrations along the bottom of the same channel (i.e. in mol/m^3) - I then normalize these concentrations against the inlet concentration. Shouldn't these too normalized graphs be the same (assuming nothing else happens [other changes in temperature and pressure] - and both cases are describing the same system under the same conditions)?