Lohafex project update: Iron fertilization in Southern Ocean fixes little CO2

Some processes involved in iron fertilization of the ocean.

The BBC reports that the Lohafex project team (Loha in Hindi stands for iron) found negligible CO2 fixation upon iron fertilization in the Southern Ocean, in contrast to smaller-scale studies which indicated that the iron addition would help fix CO2 by the sinking of the dead plankton biomass.
As shown in the figure, this is a delicate balance between nutrient availability, settling rates and other creatures which consume phytoplankton. The team found that the additional plankton was consumed by microscopic animals. Additionally, the team discovered that their experiment ran into silicic acid (H4SiO4) limitations, with the result that diatoms were not the dominant species observed in the bloom.