Can Large-scale Pumps Inject Oxygen And Life Into The Lifeless Seabed Of The Baltic?

The Baltic Sea is actually characterised by a high phosphate content and by a considerable algal bloom during the summer. But it has not always been like that.

During the 1990s the phosphorus content in the Baltic fell by a third, a reduction which coincided with a marked thermocline which increased the oxygen content down to a depth of 120 m. These circumstances show that it should be possible to bring about a rapid reduction in the eutrophication symptoms in the Baltic proper, by adding water that is rich in oxygen in an artificial way and mixing the bodies of water intensively.

The question is whether it is possible to maintain the Baltic in this oxygen rich state, by continuously adding oxygen rich water to the deep water. This is what will now be investigated in a pilot project conducted by researchers from the University of Gothenburg. The project, called Box, is receiving support amounting to SEK 20 million from Formas and the Swedish National Environmental Protection Agency (Naturvårdsverket).

"We are going to investigate how you succeed in retaining the phosphorus in the bottom sediment under different external circumstances, with and without artificial oxygenation, in two coastal basins. Among other things we will be using the prototype of a wind-driven pump, but we will also investigate how a full-scale pump system in the Baltic proper might be designed," says project director Anders Stigebrandt, Professor at the Department of Earth Sciences at the University of Gothenburg.