Iron Fertilization
Adding small amounts of iron to the ocean’s surface can trigger a bloom of phytoplankton big enough to be seen from space. Such additions happen naturally, such as when winds blow dust from the Sahara Desert or ash from a volcanic eruption. When the plume of dust or ash settles over the ocean’s surface, it triggers massive blooms of phytoplankton that remove substantial amounts of carbon dioxide from the atmosphere. Iron fertilization is a Carbon Dioxide Removal (CDR) technique that would mimic this natural system, artificially adding iron to the ocean’s surface to stimulate growth of phytoplankton.
New technologies using autonomous platforms and sensors now exist that allow scientists to fully investigate the potential for iron to remove atmospheric carbon and track the subsequent movement of that carbon through the ocean. Because iron fertilization would be relatively inexpensive, it could be an important part of a suite of CDR activities aimed at removing excessive amounts of carbon dioxide from our atmosphere. But it’s important to remember that such approaches do not replace the need for immediate and major reductions in the use of fossil fuels that produce carbon dioxide in the first place.