Sea-bed oxygenation can solve eutrophication

Environmental Research Web: Researchers at the University of Gothenburg in Sweden have demonstrated that pumping oxygen-rich surface water down to the sea floor is an effective method of dealing with eutrophication. The researchers, led by Anders Stigebrandt, conducted pilot studies in two fjords in Sweden. A large wind-driven pump is now to be tested in open water in the Baltic.

The team found that oxygenation of the sea bed creates the necessary conditions for the establishment of new ecosystems that enable nature to deal with eutrophication.

"Today everyone is focused on reducing nutrient inputs to the sea to reduce eutrophication in the Baltic, but by helping nature to deal with the phosphorus that is discharged we can create a turbo effect in the battle against eutrophication," says Stigebrandt. "If oxygen-free bottoms in the Baltic are oxygenated, it can be anticipated that every square kilometre of bottom surface will be able to bind 3 tonnes of phosphorus in a short time, which is a purely geochemical effect. If the bottoms are then kept oxygenated for a prolonged period, fauna becomes established on and in the bottoms. This leads to the bottom sediments being oxygenated down to a depth of several centimetres, and the new ecosystem probably contributes to the possibility of further phosphorus being bound to the sediment."…

A phytoplankton bloom the Baltic Sea, shot by NASA