Gas solubility in water decreases pretty strongly due to the gaseous phase being more entropic (in governing thermodynamic potentials the entropic term is -T•∆S). Unfortunately this is unavoidable with rising temperatures.
>For example, the midwaters off of Central California have lost 40% of their oxygen in the last few decades.
As the oxygen carrying capacity of water is very low, an increase in temperature, that increases the overall consumption rates of organisms near the surface, could cause large magnitude changes in DO concentrations.