Adding Iron To The Ocean Can Remove CO2 - But At What Cost To Nature? (newswise.com)

Newswise — Adding iron to the ocean can cause plankton to absorb more CO2 from the atmosphere. However, the effect depends on where in the world the method is used, and it can have far-reaching consequences for marine ecosystems and food chains, according to a new study in Nature. Phytoplankton, microscopic plant-like organisms that drift through the ocean, play a central role in the ocean’s uptake of CO2. Through photosynthesis, plankton absorb carbon dioxide from the atmosphere, and some of this carbon dioxide is transported to the deep sea when the organisms die or are eaten. In large parts of the world’s oceans, however, growth is limited by a lack of iron, which is an essential nutrient. For this reason, researchers have for decades been investigating whether the ocean’s CO2 uptake can be increased by adding dissolved iron to iron-deficient areas. But how effective is this method, and what are its consequences for marine ecosystems? Professor Adam Martiny, DTU Aqua, has investigated this in a new study, which has been published in the prestigious scientific journal Nature. Using an advanced ocean model, the researchers have simulated 60 years of iron addition in ten different ocean regions to investigate both the...