Is ocean iron fertilization back from the dead as a CO₂ removal tool?
by Jeremy Hance, Conversation News, November 14, 2023
“In 2009, a controversial scientific experiment dumped 6 metric tons of dissolved iron into the Southern Ocean to see if it would trigger a massive bloom of phytoplankton in iron-deficient waters. In one way, the experiment succeeded: The scientists produced a phytoplankton bloom. However, they didn’t get what they were really after: Proof that such a scheme could lead to large-scale carbon dioxide sequestration. You see, when phytoplankton die, they sometimes sink to the bottom of the sea — a phenomenon known as marine snow — carrying the carbon dioxide they absorbed during photosynthesis with them to be sequestered in the seabed for decades to millennia. In 2009, the vast majority of the experimental bloom was consumed by zooplankton near the surface and failed to reach the ocean floor. Since then, except for an even more controversial attempt by a for-profit company in 2012 in Canadian waters, there have been no large-scale experiments of ocean iron fertilization as a potential tool to counteract climate change.”