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Potential Risks of Ocean Iron Fertilization Include Oxygen Depletion

Ocean Iron Fertilization (OIF) has emerged as a contentious geoengineering technique aimed at enhancing the ocean's biological carbon pump to combat climate change. By introducing iron to iron-deficient regions of the ocean, proponents aim to stimulate the growth of phytoplankton, which absorb atmospheric carbon dioxide (CO2) and eventually sequester it in the deep ocean as they die and sink. While this approach holds promise, it is fraught with potential ecological risks that could far outweigh its benefits. Among these risks is oxygen depletion.

Oxygen Depletion (Hypoxia)​

The massive phytoplankton blooms resulting from OIF eventually die and decompose, a process that depletes oxygen in the water. This can lead to hypoxic conditions or "dead zones," where oxygen levels are too low to support most marine life. Such conditions can cause significant biodiversity loss and disrupt entire marine habitats, further compounding the ecosystem imbalance initiated by iron addition.12345

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Footnotes​

  1. International Union for Conservation of Nature (IUCN). (2023, January). Ocean deoxygenation links to harmful algal blooms. https://portals.iucn.org/library/sites/library/files/documents/03.3%20DEOX.pdf ↩

  2. Peng, L., Lan, C. Q., & Zhang, Z. (2013, August). Evolution, detrimental effects, and removal of oxygen in microalga cultures: A review. Environmental Progress & Sustainable Energy, 32(4), 982-988. https://doi.org/10.1002/ep.11841 ↩

  3. Limburg, K. E., Breitburg, D. L., Swaney, D. P., & Jacinto, G. S. (2020, January). Ocean deoxygenation: A primer. One Earth, 2(1), 24-29. https://doi.org/10.1016/j.oneear.2020.01.001 ↩

  4. Altieri, A. H., & Díaz, R. J. (2019, January). Dead zones: Oxygen depletion in coastal ecosystems. In Coastal and Marine Hazards, Risks, and Disasters (pp. 453-473). Elsevier BV. https://doi.org/10.1016/b978-0-12-805052-1.00021-8 ↩

  5. Díaz, R. J., & Rosenberg, R. (2008, August). Spreading dead zones and consequences for marine ecosystems. Science, 321(5891), 926-929. https://doi.org/10.1126/science.1156401 ↩