What happens if you add oxygen to water lacking oxygen?

[MulderFBI]

Does adding oxygen influence any physical properties of water which is oxygen deficient? Is it possible that adding oxygen leads to some temperature change and expansion?

 

[berkeman]

Does adding oxygen influence any physical properties of water which is oxygen deficient?

I would think that the aquatic plants and fish would care...

Is it possible that adding oxygen leads to some temperature change and expansion?

Why a temperature change? I'm assuming the temperature of the O2 introduced matches the H2O temperature, right?

And why would it change the density? Does the O2 dissolve or not?

 

[MulderFBI]

I would think that the aquatic plants and fish would care...

Why a temperature change? I'm assuming the temperature of the O2 introduced matches the H2O temperature, right?

And why would it change the density? Does the O2 dissolve or not?

No it doesn't - oxygen comes from surface air (lets say ranging from 10-30 degrees) and it mixes with deoxygenated water at 4 deg celsius. And the expansion should come from temperature increase (above 4deg anomaly point) but I would like to know if that really happens.

The air will be implemented with a gore-tex like membrane allowing O2 or air molecules to enter deoxygenated water but not allowing water to get out. So if O2 comes from hotter than water air will this lead to temperature increase or it's more complex? I wonder...

 

[jim mcnamara]

Assuming lake or pond water in a fixed volume, not chlorinated tap water:
Pond water has lots of organisms that use oxygen, so adding oxygen changes the bacterial makeup of the water because the aerobic beasties are dormant when oxygen levels are low. Oxygen is toxic to anaerobes, so they shut down. This can raise pH because anaerobes produce molecules like H₂S that are acidic.

You are throwing off questions you could answer, so you get to give us the answer. Note that warming water decreases oxygen solubility, so does altitude.

Off the cuff ignoring some complications:
Assume that oxygen dissolved in water has zero solution volume, I'm not looking that up right now. If you "magically" add oxygen at 50 °C to the entire volume of 100L of pond water at 20 °C to a level of 10g/L you have added 1000g of "hot" oxygen to the tank. You have 1000g at 50 plus 100*1000g at 20 °C in the same volume. The temperature will rise by _____ degrees. (hint: this is not a big number)

Note: you will get evaporative cooling by adding oxygen via the surface. I do not know precisely what happens when you bubble warm oxygen into a tank of colder water in terms of evaporative cooling -- some has to exist. I gather that @Bystander probably knows a priori. I'm also ignoring the fact that gas dissolution in water is usually exothermic - so warm bubbles probably ultimately cool the water. Don't know.

 

[Bystander]

that @Bystander probably knows a priori.

Solubility is very approximately equal volumes at STP; this thread is going to be locked under the "PMM" clause, so, I've been ignoring it.

 

[jim mcnamara]

Yup. It is locked now.