Global International Waters Assessment is a systematic assessment of the environmental conditions and problems in large transboundary waters, comprising marine, coastal and freshwater areas, and surface waters as well as ground waters. Involving over 1,500 expert it has assessed 66 of the world’s major river basins and recently published a synthesis report. These publications are freely available online. The synthesis report‘s section on pollution provides a map of eutrophication impact.

As mentioned in a earlier post on mapping dead zones, eutrophication can produce large coastal hypoxic zones. The GIWA regional assessments reported that dead zones:

… have become increasingly common in the world’s lakes, estuaries and coastal zones, with serious impacts on local fisheries, biodiversity and ecosystem functions. Extensive dead zones have been observed for many years in the Baltic Sea, Black Sea and Gulf of Mexico. The GIWA assessment has compiled information on dead zones in the Southern Hemisphere, including several lagoons in the Brazil Current region, coastal locations in the Humboldt Current region, and in the Yangtze River estuary located in the East China Sea region.