Oxygen in Black Sea has declined by more than a third since 1955
Surface, O2-rich layer shrank, decreasing habitable volume and moving toxic waters closer to atmosphere

SUFFOCATING SEA The Black Sea lost 36 percent of its oxygen from 1955 through 2013, new research finds. The sea’s oxygen-rich surface water insulates the atmosphere from toxic deep waters.
Alexandru Panoiu/Flickr (CC BY 2.0)