A novel analysis of water flow in the Southern Ocean surrounding the Antarctic is revealing previously hidden structures that are crucial in controlling the transport of drifting plants and animals as well as the distribution of nutrients and pollutants that affect ocean life.

Researchers at the University of New South Wales in Australia and the Universitat Paderborn in Germany discovered that barriers to currents, which can lead to swirling gyres and eddies that trap material for long periods, may escape detection with traditional analyses that concentrate on monitoring average water flow or sea surface height.



Rather than tracking flow in the ocean point by point, as is typical of most ocean studies, the researchers applied a more holistic approach based on a mathematical technique known as Lagrangian analysis. In effect, the method allows them to simultaneously consider all the possible ways that currents can move in the ocean, and then pick out the most likely solution.

When the team tested their approach on a simulated model of ocean current flow, they found that regions where drifting material might be trapped in seas near the Antarctic were clearly identified with the Lagrangian approach. Traditional analyses, however, can only hint at the regions' locales. The researchers plan to extend their study to encompass current flow on a global scale. The work should help to provide a clearer picture of the currents that are vital to the health of our planet's oceans.

Source: Physical Review Letters, G. Froyland, K. Padberg, M. H. England, A. M. Treguier