according to a weekend report in the uk’s independent a new study shows that oceanic “dead zones” are on the increase globally and now number at about 150. this number is double that of 10 years ago.
dead zones in the sea are created as part of a chain of events starting with an excess of nutrients – nitrogen being key – that build up and cause excessive blooms of phytoplankton and other alages. when these blooms die and rot, they consume oxygen at a rapid rate, suffocating all other marine life.
agricultural fertilizers, vehicle and factory emissions, and human wastes are to blame for the increase in dead zones, some of which take up 70,000 square kilometres and are growing. the impacts of such zones on fish and fisheries is fairly obviousl as large swaths of the world’s seas become uninhabitable for any plant or animal life.