The Alfred Wegener Institute for Polar and Marine Research explained that the addition of iron to 300 square kilometres of the South Atlantic did promote plankton growth, but they were unexpectedly eaten by small crustacean zooplankton before they could absorb more of the greenhouse gas.
“Nevertheless, despite the hard work under difficult circumstances, LOHAFEX has been an exciting experience laced with the spirit of adventure and haunted by uncertainty quite unlike other scientific cruises,” said Dr. Victor Smetacek, co-chief scientist from the Alfred Wegener Institute, which took the German research boat Polarstern on the journey.
Based on the preliminary results, the team doubts that iron fertilisation will lead to a removal of significant amounts of CO2 from the atmosphere, the statement said.
Such experiments are called geo-engineering and have been highly controversial among environmentalists because of their unpredictable results.
The decision to allow the experiment to go ahead with India's National Institute of Oceanography (NIO) caused divisions within Germany's coalition government in late January. Research Minister Annette Schavan, who is a member of Chancellor Angela Merkel's conservative Christian Democrats, gave the test the green light, saying "after a study of expert reports, I am convinced there are no scientific or legal objections against the... ocean research experiment LOHAFEX."
But a spokesman for the environment ministry, headed by centre-left Social Democrat member Sigmar Gabriel, later said in the statement that the ministry "regrets the decision" to approve the LOHAFEX test. Gabriel had reportedly told Schavan in an earlier letter that the experiment "destroys Germany's credibility and its vanguard role in protecting biodiversity."
Researchers from the Alfred Wegener Institute said that the experiment had left behind “no trace other than a swarm of well-fed amphipods.”