NCAR: Global Temperature Increase Depletes Oxygen in Most Ocean Zones by the 2030s
Scientists know that a warming climate can be expected to gradually sap the ocean of oxygen, leaving fish, crabs, squid, sea stars, and other marine life struggling to breathe.
The entire ocean—from the depths to the shallows—gets its oxygen supply from the surface, either directly from the atmosphere or from phytoplankton, which release oxygen into the water through photosynthesis. Warming surface waters, however, absorb less oxygen. And in a double whammy, the oxygen that is absorbed has a more difficult time traveling deeper into the ocean. That’s because as water heats up, it expands, becoming lighter than the water below it and less likely to sink.