Occurrence of reduced oxygen concentrations in Europe's coastal and marine waters, average 2013-2024

The map shows the mean 5-percentile of dissolved oxygen (DO) concentrations in near-bottom waters during summer-autumn months over the period 2013-2024, divided into four classes (<2mg/l; 2-4mg/l; 4-6mg/l and >6mg/l). The pie charts show the relative spatial coverage of the four DO concentration classes aggregated by marine region - North-East Atlantic, Baltic Sea, Mediterranean Sea and Black Sea (smaller pie charts) and across all regions combined (large pie chart in the centre). Oxygen concentrations above 6mg/l are considered to support marine life with minimal stress, while concentrations below 2mg/l (hypoxia, oxygen deficiency) are considered to cause severe problems.