Oceans running out of oxygen, say scientists

[Still Waters]

Climate change and nutrient pollution are driving the oxygen from our oceans, and threatening many species of fish.

That's the conclusion of the biggest study of its kind, undertaken by conservation group IUCN.

While nutrient run-off has been known for decades, researchers say that climate change is making the lack of oxygen worse.

Around 700 ocean sites are now suffering from low oxygen, compared with 45 in the 1960s.

Researchers say the depletion is threatening species including tuna, marlin and sharks.

https://www.bbc.co.uk/news/science-environment-50690995

[Doug1029]

Oxygen depletion is a function of pollution.  Organisms in the water break down the pollutants, using up oxygen as they do so.  During daylight this is not a problem as the oxygen is replaced by photosynthesis.  But at night there is no photosynthesis.  Fish and other things that need to breath die from a lack of oxygen, creating dead zones.

Doug