German researchers set sail on novel global warming expedition

Brussels, 26 Jan 2004

50 German researchers from the Alfred Wegener institute for polar and marine research have put to sea in order to find out whether adding iron to the Southern Ocean will help to permanently remove carbon dioxide (CO2) from the atmosphere, thus alleviating global warming.

The theory is that the iron will encourage the growth of phytoplankton, a single celled algae that absorbs CO2 from the atmosphere during photosynthesis. Phytoplankton are believed to be responsible for almost half of the total photosynthetic activity on Earth.

While the idea has already been tested on a small scale, the long term effects of adding large quantities of iron to the ecosystem are not known. Furthermore, as the institute's Victor Smetacek explains, the absorbed CO2 will only be removed from the air permanently if the phytoplankton die and sink to the bottom of the sea. If not, the CO2 in the plankton will simply move up the food chain and eventually be re-released into the atmosphere through the respiration of larger sea creatures.

In order to find the answers to both these questions, scientists aboard the German research vessel Polarstern will dissolve an iron sulphate solution in a 150 to 200 square kilometre area of the Southern Ocean. Using a helicopter, they will then monitor the growth of phytoplankton, and examine the impact on other sea creatures for a period of eight to ten weeks.

'We need to find out whether the algae die after the bloom and sink down to the ocean floor,' said Dr Smetacek. 'Only then can we be sure that the carbon is permanently removed from the atmosphere.'

Scientists warn that even if this part of the of the theory is proved effective, the associated interference with the marine food chain could have a dramatically negative effect on ocean ecology as a whole.

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