Measurements of carbon dioxide concentrations and isotopic ratios from air samples collected at the surface and at altitude between New Zealand and the South Pole to determine if the Southern Ocean is a carbon sink

The role of the Southern Ocean as a carbon sink in the carbon cycle was investigated by collecting air samples at regular intervals between New Zealand and McMurdo Sound both at the surface and at altitude to determine changes in concentration and isotopic composition of air both at the ocean surface and at altitude in the free troposphere.

The samples were measured for CO2 concentration and 13C/12C ratios. The shifts observed at the surface due to an ocean sink will be much stronger than those at altitude and from this sink strength can be calculated.