How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic

The Adaptive Capacity of Sea Urchin Embryos to Ocean Warming and Acidification
Foo, S.A., Dworjanyn, S.A., Poore, A.G.B. and Byrne, M. 2012. Adaptive capacity of the habitat modifying sea urchin Centrostephanus rodgersii to ocean warming and ocean acidification: Performance of early embryos. PLoS ONE 7: e42497.

The authors write that "selection by stressful conditions will only result in adaptation if [1] variation in stress tolerance exists within a population, if [2] tolerance of stressors is heritable, and if [3] changes in tolerance traits are not constrained by negative genetic correlations with other fitness traits," citing references both old and not so old: Darwin (1859) and Blows and Hoffmann (2005).

What was done
In harmony with these principles, Foo et al. indicate that they "quantified genetic variation in tolerance of early development of the ecologically important sea urchin Centrostephanus rodgersii to near-future (2100) ocean conditions projected for the southeast Australian global change hot spot," wherein "multiple dam-sire crosses were used to quantify the interactive effects of warming (+2-4°C) and acidification (-0.3-0.5 pH units) across twenty-seven family lines" of the species.

What was learned
The four Australian researchers report that "significant genotype by environment interactions for both stressors [warming and acidification] at gastrulation indicated the presence of heritable variation in thermal tolerance and the ability of embryos to respond to changing environments." And they say that "positive genetic correlations for gastrulation indicated that genotypes that did well at lower pH also did well in higher temperatures."

What it means
In the concluding paragraph of their paper, Foo et al. affirm that "the presence of tolerant genotypes, and the lack of a trade-off between tolerance to pH and tolerance to warming contribute to the potential of C. rodgersii to adapt to concurrent ocean warming and acidification, adding to the resilience of this ecologically important species in a changing ocean."

Blows, M.W. and Hoffmann, A.A. 2005. A reassessment of genetic limits to evolutionary change. Ecology 86: 1371-1384.

Darwin, C. 1859. On the Origin of Species. John Murray, London, United Kingdom.

Reviewed 13 February 2013