At a river I fish there is a gas line or something that is underwater  and runs out to almost the main channel on the river....Well there is holes or something and in this one spot there is a bunch of bubbles everywhere and its like an arreator under the water and the area that is arreated is about 26 to 40 foot.  Now in the summer I can go out there and never move the boat all day and catch fish my guess is they would chase shad through the bubbles or something....Well went out there the other day and the graph looked like there might be some fish on the very bottom but i didnt get a bite and fished it for a while. Would they be even around water like this in the winter....the waters about 47to 50

Warm water holds less dissolved oxygen. Perhaps in the summer that is why they are more attracted to this area than they are in the winter.

When stream water gets too warm for trout, they will move into riffles. In a stream it's not that there is more oxygen in a given volume of water in a riffle, but that the fish can utilize what's called ram-jet ventilation -letting the force of the water move through the gills, while the fish sits quiet conserving energy. In still water they would have to physically pump that low oxygenated water through, at a high rate -like us breathing hard when out body tells us we need more 02.

In your situation it's less likely an O2 issue being a river (although if it's somewhat stagnant with high temps, it could be). More likely those fish are using that bubble curtain as structure/cover like you suspected. In trout streams the "bubble curtain" below falls is used by fish like this.

In winter, my guess is those fish are on bottom bc they are avoiding current in that cold water.

Those are my guesses from afar.