How much dissolved oxygen is in normal ocean water?

Oxygen is sea water is much less than 0.6% it's about 10–15 parts per million ( mg/L ) in fresh water and 8–11 ppm in sea water , but fish can happily work with this very low concentration because the surface area of their gills is very large. Fish will be stressed at 5ppm but at around 10ppm they thrive. read more

As the amount of dissolved oxygen drops below normal levels in water bodies, the water quality is harmed and creatures begin to die off. Indeed, a water body can "die", a process called eutrophication. read more

According to Henry’s Law, the dissolved oxygen content of water is proportional to the percent of oxygen (partial pressure) in the air above it 13. As oxygen in the atmosphere is about 20.3%, the partial pressure of oxygen at sea level (1 atm) is 0.203 atm. read more