Wiktionary
n. the reduction in the concentration of dissolved oxygen in water, especially as a result of pollution
Usage examples of "oxygen depletion".
At least two dozen potential culprits have been identified as causes or prime contributors: global warming, global cooling, changing sea levels, oxygen depletion of the seas (a condition known as anoxia), epidemics, giant leaks of methane gas from the seafloor, meteor and comet impacts, runaway hurricanes of a type known as hypercanes, huge volcanic upwellings, catastrophic solar flares.
Soon all the mass media were off the air and Walter had had reports that pressure had been breached in several major cities, and other places had suffered oxygen depletion.
Whereas humans went slightly blue, when done to death by oxygen depletion, the Posleen went greenish.
A long time she hung there, sensing, while those she sought, with burning lungs, endured the scarlet flashes of oxygen depletion vivid against their eyelids.
So rapid was one of the upward rushes that his ears popped repeatedly, and he felt the first faint symptoms of oxygen depletion.