Baltic Sea hypoxia

Baltic Sea hypoxia refers to low levels of oxygen in bottom waters, also known as hypoxia, occurring regularly in the Baltic Sea. As of 2009 the total area of bottom covered with hypoxic waters with oxygen concentrations less than 2 mg/L in the Baltic Sea has averaged 49,000 km2 over the last 40 years. The ultimate cause of hypoxia is excess nutrient loading from human activities causing algal blooms. The blooms sink to the bottom and use oxygen to decompose at a rate faster than it can be added back into the system through the physical processes of mixing. The lack of oxygen (anoxia) kills bottom-living organisms and creates dead zones. rdf:langString