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‘Iron Fertilization’ kicks up dust

Artificial iron fertilization of the oceans is at least 10 times less efficient in carbon sequestration than its natural equivalent, but that does not stop private companies trying.

Results from the KEOPS cruise carried out in the Southern Ocean show that natural iron fertilization from the plateau’s sediments produces atmospheric CO2 drawdown 2-3 times higher than that observed during seeding experiments. This is a direct result of the eightfold higher dissolved iron flux from the plateau’s sediments to the surface waters, compared to windswept dust. The seasonally sustained supply of easier to assimilate forms of iron (see also Boyd et al., Science, 2 Feb 2007), results in carbon export from the surface waters that is at least 10 times greater than that observed during the dozen or so short seeding experiments performed between 1993 and 2005.

In conclusion, the authors ‘emphasize that the high sequestration efficiency determined in the Kerguelen bloom should not be taken as an indication that controversial geoengineering CO2 mitigation proposals will be able to obtain high efficiencies’. The paper is published just before the first commercial ocean iron fertilization project gets under way. The privately funded, self-proclaimed eco-restoration company Planktos aims to iron-fertilize 10 000 km sq. of ocean around the Galapagos Islands in an effort to explore the method’s viability as a climate mitigation strategy, and targets the international carbon credit market for offsetting corporate CO2 emissions.

Reference:
Stéphane Blain* et al., 2007. Effect of natural iron fertilization on carbon sequestration in the Southern Ocean, Nature Volume 446(7139), 26 April 2007, pp 1070-1074 *EUROCEANS PI

RELEVANT LINKS: Iron Fertilization in the Press:
- NatureNews.com, 3 March 2008 - PLANKTOS dead in the water
- New York Times, 7 Nov 2007 - Seagoing Climate Experiment Begins;
- The Times (UK) 3 May 2007 - How the surge in plankton may be the saviour of mankind
- IPCC Mitigation of Climate Change - 4 May 2007
- The Independent (UK) 3 May 2007 - Researchers 'seed' ocean with iron to soak up CO2;
- New York Times (USA) 1 May 2007 - Recruiting Plankton to Fight Global Warming;
- Le Monde (France) 28 April 2007 - L'épandange de fer dans l'océan ne favoriserait pas l'absorption de CO2 par le plancton
- Figaro (France) 26 April 2007 - Capter du CO2 dans les océans : l'espoir recule;



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