Levels of nitrogen in the East China Sea, Yellow Sea, and Sea of Japan have risen sharply over the last 30 years because of growing industrial and agricultural pollution, according to a new study in the journal Science.
Analyzing data from the 1980s to the present, Korean researchers found that nitrogen levels had quadrupled in many areas, increasing the threat that these Pacific Ocean waters will suffer from algal blooms and dead zones with low oxygen levels.
Nitrogen pollution was particularly acute in the waters close to China, where nitrogen oxide pollution from coal-burning power plants and nitrogen runoff from fertilizers have soared in recent decades as China’s economy has boomed.
In one area, the Korean researchers measured nitrogen concentrations of 8 micromoles per liter of water — 30 times higher than concentrations found in the Gulf of Mexico, which has experienced massive algal blooms in recent years.
The Korean scientists said they were surprised to see high nitrogen levels in such large, deep bodies of water as the Sea of Japan, adding that their results offered evidence that growing nitrogen pollution is altering the chemical balance of the oceans. Algal blooms have also plagued many inland bodies of water in China.
Article appearing courtesy Yale Environment 360.