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Potential Risks of Ocean Iron Fertilization Include Ecosystem Disruption

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 are ecosystem disruption.

Ecosystem Disruption​

Intervening in the nutrient dynamics of marine ecosystems through OIF can lead to profound disruptions. Phytoplankton, the primary beneficiaries of added iron, can proliferate rapidly, outcompeting other species and altering the existing food web. Such shifts can have cascading effects, potentially reducing biodiversity and altering the functional dynamics of ecosystems. Species that thrive under typical nutrient conditions may suffer from the sudden abundance of phytoplankton, which can also alter habitat structures and nutrient availability for a range of marine organisms.123

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Footnotes​

  1. Martin, J., Coale, K., Johnson, K., et al. (1994). Testing the iron hypothesis in ecosystems of the equatorial Pacific Ocean. Nature, 371(6711), 123-129. https://doi.org/10.1038/371123a0 ↩

  2. Cullen, J. J., & Boyd, P. W. (2008). Predicting and verifying the intended and unintended consequences of large-scale ocean iron fertilization. Marine Ecology Progress Series, 364, 295-301. https://doi.org/10.3354/meps07551 ↩

  3. Smetacek, V., Klaas, C., Strass, V., et al. (2012). Deep carbon export from a Southern Ocean iron-fertilized diatom bloom. Nature, 487(7394), 313-319. https://doi.org/10.1038/nature11229 ↩