Ocean Acidification and Non-Calcifying Organisms

While the vast majority of research to date on ocean acidification has focused on potential impacts of rising levels of carbon dioxide on ocean calcareous organisms. However, a new study in the Proceedings of the Royal Society, B (subscription required) suggests that ocean acidification may also have serious implications for some non-calcareous species also, with the focus of the article on an extremely important oceanic ecosystem, kelp forests . The article also looks at the interesting issue of how ocean acidification and rising oceanic temperatures associated with climate change may exert synergistic effects.

The key take-aways from this study are as follows:

  1. While future projected levels of carbon dioxide had no positive effect on turf-forming algae, which can inhibit the growth of, and replace, kelp forests, when these future elevated levels are combined with projected increases in temperature.
    • When future carbon dioxide and temperature impacts are factored in, turfs occupied greater than 80% of available space, a full 25% more space that would be predicted by the independent effects of carbon dioxide and temperature;
    • The combined effects of carbon dioxide and increase temperature are projected to be 4x greater than ambient conditions
  2. Kelp loss may thus be exacerbated by the synergistic impacts of increasing carbon dioxide levels and temperatures. Unlike the case of nutrients, this will potentially cause habitat shifts even on “pristine” coasts

Increasing evidence that ocean acidification may adversely impact non-calcareous organisms, as well as the prospects for synergistic impacts, emphasizes the urgency of far more extensive research on ocean acidification. This could be an excellent law review article topic for students, as there has been some discussion about using U.S. domestic instruments e.g. the Clean Water Act, to regulate acidification, as well suggestions that several international instruments, e.g. UNCLOS and UNFSA may play a role in the future.

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