NIWA biological oceanographer Dr Philip Boyd explains the iron hypothesis: what it is, its history, and some recent experiments in the Southern Ocean.
The hypothesis proposes that, in parts of the ocean that are deficient in iron, this deficiency limits phytoplankton growth, so adding iron should promote it. Philip describes a recent experiment where NIWA scientists dissolved an iron salt and spread it across 1000 square kilometres of the Southern Ocean, a very iron-deficient ocean. They produced a phytoplankton bloom visible from space, confirming the iron hypothesis. A further experiment showed that adding iron to the Southern Ocean is an ineffective solution to climate change.