The Southern Ocean plays a major role in the climate system, and is recognized as the ocean most sensitive to climate change . The control of biological productivity e.g. the phytoplankton community by iron in the Southern Ocean has been shown by iron adding experiments.
The availability of iron limits biological productivity and the associated uptake of carbon over large areas of the ocean. Iron plays an important role in the carbon cycle, and changes in iron supply to the ocean surface may have had a significant effect on atmospheric carbon dioxide concentrations.
Blain and his colleagues in Nature 2007, 26th April , vol 446, pp 1070-74, have shown that a large phytoplankton bloom over the Kerguelen plateau in the Southern Ocean is maintained by the supply of iron and major nutrients to surface waters from iron-rich deep water below. The efficiency of fertilization, defined as the ratio of the carbon export to the amount of iron supplied, was at least ten times higher than previous estimates from short-term blooms induced by iron-addition experiments’. This result sheds new light on the effect of long-term fertilization by iron and macronutrients on carbon sequestration, suggesting that changes in iron supply from below may have a more significant effect on atmospheric carbon dioxide concentrations.
However another major factor is the availability of carbon to convert into organic materials. ( Boyd Nature 2007, vol 446, pp 989-90.
Blain and his colleagues in Nature 2007, 26th April , vol 446, pp 1070-74
- Martin Eastwood