Hello everyone. I'm sure there is a really good reason as to why this hasn't been done yet but I just wanted to ask and see if it could be done. Why can't we make a mouth peice that basically takes in water, filters out the oxygen and then expels the water back into the ocean, then takes in some more water, extracts the oxygen ect? Do we not yet have technology capable of extracting oxygen from water? Or is it just that the technology is too large for it to be used in these circumstances?