Sinking iron into the ocean could improve carbon capture

The "iron hypothesis," which proposes fertilising the ocean with iron to boost algae growth and sequester carbon dioxide, is far more complex than initially thought. While early experiments supported the idea, subsequent research has shown that the carbon capture benefits are inconsistent and may not outweigh the potential ecological risks. Natural sources of iron in the ocean are more efficient at stimulating phytoplankton growth than artificially added iron, which often rusts and sinks where it cannot benefit algae. The complexity of iron bioavailability in seawater suggests that further ocean iron fertilisation experiments should be avoided, according to polar oceanographer Audrey Fourquez. (CORDIS)