The Tiny Crustaceans and the Co2

We haven’t heard a lot about the iron fertilisation controversy in the Antarctic for a while – at least not in the mainstream media.

(The German research vessel Polarstern, belonging to the Alfred Wegener Institute for Polar and Marine Research, conducting the research with Indian partners).

– See blog entries of 9.-15-1-2009 for the background –
Are you surprised to hear that the controversial experiment did not produce the desired results? Artificially fertlizing the ocean with iron is not a way to substantially reduce the concentration of CO2 in the atmosphere!
It seems the scientists on board the Polarstern were surprised by what did actually happen during the German-Indian experiment. Here’s a short excerpt from the Alfred Wegener Institute’s summary:

“As expected, iron addition stimulated growth of the planktonic algae (phytoplankton), which doubled their biomass within the first two weeks by taking up CO2 from the water. “However, the increasing grazing pressure of small crustacean zooplankton (copepods) prevented further growth of the phytoplankton bloom,” explains Dr Wajih Naqvi, co-chief scientist from the National Institute of Oceanography of the Council of Scientific and Industrial Research. Those algal species, which regularly make blooms in coastal regions including the Antarctic, were most heavily grazed. As a result, only a modest amount of carbon sank out of the surface layer by the end of the experiment. Hence, the transfer of CO2 from the atmosphere to the ocean to compensate the deficit caused by the LOHAFEX bloom was minor compared to earlier ocean iron fertilization experiments. ”

Clausocalanus laticeps
The smaller copepod species Clausocalanus laticeps with orange bands round its midriff.
Photo: G. Mazzochi, SZN / Alfred Wegener Institute