This 3D scene shows the distribution of dissolved lead (Pb) in the Atlantic. At a depth of about 500 to 2,000 metres a red band runs across the Atlantic Ocean. It indicates relatively high lead concentrations. The increased concentrations are due to emissions of car exhaust gases in Europe and North America that found their way into the environment prior to the introduction of unleaded petrol. In the image South America is on the left while Africa is on the right.