How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic

How Southern Ocean Echinoderm Larvae Respond to Elevated CO2
Yu, P.C., Sewell, M.A., Matson, P.G., Rivest, E.B., Kapsenberg, L. and Hofmann, G.E. 2013. Growth attenuation with developmental schedule progression in embryos and early larvae of Sterechinus neumayeri raised under elevated CO2. PLOS ONE 8: e52448.

The authors write that "the Southern Ocean, a region that will be an ocean acidification hotspot in the near future, is home to a uniquely adapted fauna that includes a diversity of lightly-calcified invertebrates," and, hence, they felt it important to investigate how the early life stages of one of these life forms are impacted by the levels of atmospheric CO2 enrichment being predicted to occur within the current century.

What was done
Yu et al., as they describe it, utilized the sea urchin Sterechinus neumayeri to test the effects of high CO2/low pH on early development and larval growth by exposing them to environmental levels of CO2 in McMurdo Sound (control: 410 ppm) and mildly elevated CO2 levels, both near the level of the aragonite saturation horizon (510 ppm), and to under-saturating conditions (730 ppm).

What was learned
The six scientists report that over the course of development from egg to late four-arm pluteus, they found that "(1) early embryological development was normal with the exception of the hatching process, which was slightly delayed, (2) the onset of calcification as determined by the appearance of CaCO3 spicule nuclei was on schedule, (3) the lengths of the spicule elements, and the elongation of the spicule nuclei into the larval skeleton, were significantly shorter in the highest CO2 treatment four days after the initial appearance of the spicule nuclei, and (4) finally, without evidence of true developmental delay, larvae were smaller overall under high CO2 treatments; and arm length, the most plastic morphological aspect of the echinopluteus, exhibited the greatest response to high CO2/low pH/low carbonate conditions."

What it means
After all was said and done, Yu et al. concluded, in the final sentence of their paper's abstract, that "effects of elevated CO2 representative of near future climate scenarios are proportionally minor on these early development stages."

Reviewed 19 June 2013