Plankton fed with iron will absorb carbon dioxide to prevent it acting as a greenhouse gas, scientists have shown.
Measurements taken in the Southern Ocean around Antarctica confirmed that so-called "iron fertilization" would help plankton to grow and thus take in more carbon. Indeed, they took the carbon so deep under the water that it would be locked away for a century.
The results, achieved by a team from the National Oceanography Centre in Southampton, England, were hailed by rival researchers as a significant step in the search for ways to reduce carbon in the atmosphere.
But hopes that the technique could be developed commercially to counteract global warming took a blow because far less carbon was taken out of circulation than some experts had predicted.
Iron fertilization is one of several schemes that have been put forward to try to slow global warming. The theory is that if tons of iron particles are dropped into the ocean, they would stimulate the growth of plankton that would remove carbon from the atmosphere.