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
![black sea](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/10/100815_ts_blacksea_free.jpg?fit=860%2C460&ssl=1)
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)