Study: Fertilizing oceans with iron dust helps sink carbon

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Fertilizing oceans with iron dust helps sink carbon: study

Surfersvillage Global Surf News, 23 July, 2012 : - - Dumping iron in the seas can help transfer carbon from the atmosphere and bury it on the ocean floor for centuries, helping to fight climate change, according to a study released by an international team of experts last Wednesday. The report provided a boost for the disputed use of such ocean fertilization for combating global warming. But it failed to answer questions over possible damage to marine life.

When dumped into the ocean, the iron can spur growth of tiny plants that carry heat-trapping carbon to the ocean floor when they die. Scientists dumped seven tons of iron sulphate, a vital nutrient for marine plants, into the Southern Ocean in 2004. At least half of the heat-trapping carbon in the resulting bloom of diatoms, a type of algae, sank below 1,000 meters (3,300 ft).

Burying carbon in the oceans would help the fight against climate change, caused by a build-up of carbon dioxide in the atmosphere that scientists say is raising temperatures and causing more floods, mudslides, droughts and higher sea levels. The study was the first convincing evidence that carbon, absorbed by algae, can sink to the ocean bed.

One doubt about ocean fertilization has been whether the carbon stays in the upper ocean layers, where it can mix back into the air. A dozen previous studies have shown that iron dust can help provoke blooms of algae but were inconclusive about whether it sank.

Large-scale experiments with ocean fertilization using iron are currently banned by the international London Convention on dumping at sea because of fears about side-effects.

Ocean fertilization is one of several suggested techniques for slowing climate change known as "geo-engineering". Other possibilities include reflecting sunlight with giant mirrors in space.

The publication had been delayed since 2004 partly because of problems in checking that the 150 square km (60 square miles) patch of ocean where the iron was dumped - an eddy in the Antarctic Circumpolar Current - had not mixed with waters outside. The experts said that the input of iron was similar to that found after the melt of icebergs in the oceans - iron concentrations in coastal regions tend to be much higher. Read more

Source: WNE

Author: The Editors

Tags: Global Warming, Climate Change

Environment: Surfersvillage