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Storm over planned ocean fertilization experiment (updated)

Stimulating algal growth by adding iron to nutrient-poor ocean regions is one of several geo-engineering methods that could possibly mitigate greenhouse warming. But given widespread worries about possibly harmful side-effects on marine life, large-scale ocean ‘fertilization’ is currently not considered advisable.

Predictably, environmental groups have therefore jumped on an iron fertilization experiment which an international team of oceanographers is set to conduct over the next two months in the Southern Ocean near the island of South Georgia. Critics claim that LOHAFEX violates the moratorium on ocean fertilization activities which the United Nations had agreed upon last year. The Nature news story here has more details.

The somewhat ambivalent wording of the legally binding UN Convention on Biological Diversity adds to the controversy. ‘Small-scale’ scientific experiments in ‘coastal waters’ are exempted from the moratorium, it reads. But ‘small-scale’ is a relative term, and where exactly coastal waters give way to the open ocean remains also undefined.


Picture: The Polarstern (Alfred Wegener Institute)

The team on board the German ‘Polarstern’, who plan to spread 20 tonnes of iron sulphate over less than 20 by 20 kilometres-large patch of ocean surface in the Scotia Sea, hope that the study will provide new insight into how ocean ecosystems respond to fertilization – the very data, hence, that are needed to assess whether or not larger-scale future activities might be justified. But opponents counter that such doing already qualifies as an activity banned by UN law. Pressure groups have launched a signature campaign aimed at stopping the Polarstern crew, which will reach its destination by the end of the week, from dumping its load.

A number of companies, such as the now defunct Planktos Inc., had in the past hoped to commercialize ocean fertilization for the carbon credit market. Scientists and institutes participating in LOHAFEX stress that the experiment has no commercial background whatsoever.


The Indo-German ocean fertilization experiment, LOHAFEX, has been suspended. The German science ministry, in response to environmental concerns, has asked the Alfred Wegener Institute (AWI) in Bremerhaven that an additional independent assessment be conducted before the planned activities can commence.

Meanwhile, the Polarstern, scheduled to reach the planned study region in the Scotia Sea by the end of the week, will continue its journey as planned. On arrival, the 48 scientists on board will start doing preparatory work, but the team will have to await permission from the ministry before they can dump any nutrients into the ocean. AWI has today commissioned two undisclosed institutions to carry out the required extra assessment. It hopes the reports will be delivered within ten days.

Quirin Schiermeier


  1. Report this comment

    Milan said:

    How are they actually planning to measure the amount of CO2 absorbed?

    Also, is there any way to measure how much of it stays sequestered for any particular span of time?

  2. Report this comment

    Quirin Schiermeier said:

    The team will monitor and measure the rain of organic particles as they sink through the water column following the decay of the bloom. The fate of carbon from the bloom was not precisely determined in previous experiments. LOHAFEX will investigate the partitioning of carbon between atmosphere and the deep ocean in more detail.

    To determine the flux of particles from the surface the scientists will use sediment traps, profiling cameras and Thorium isotopes. Carbon in organic particles that sink from the decaying bloom to the deep ocean is sequestered from exchange with the atmosphere for centuries.

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