ENSO‐driven carbon see saw in the Indo‐Pacific

The sediment trap experiments have been carried out during the 2001/2002 El Niño/La Niña transition in the monsoon‐driven and freshwater influenced upwelling system off South Java. The results indicate that enhanced precipitation rates and associated river discharges increase the CO 2 ‐uptake of the biological pump by increasing the organic carbon export and reducing the carbonate precipitation. The freshwater, furthermore, forms a buoyant low salinity surface layer that caps off the nutrient and CO 2 ‐rich subsurface waters which shortens the upwelling season during wet La Niña conditions. A reduced capping‐effect during dryer El Niño conditions strengthens the upwelling and as shown by our model results increase CO 2 emission into the atmosphere along the freshwater influenced continental margins in SE Asia. By contrast El Niño weakens upwelling and reduces the CO 2 emission in the equatorial Pacific Ocean.