Purple Sea Urchins: Primed for Rapid Evolution in Acidifying Seas
Pespeni, M.H., Sanford, E., Gaylord, B., Hill, T.M., Hosfelt, J.D., Jaris, H.K., LaVigne, M., Lenz, E.A., Russell, A.D., Young, M.K. and Palumbi, S.R. 2013. Evolutionary change during experimental ocean acidification. Proceedings of the National Academy of Sciences USA 110: 6937-6942.
Working with seven different populations collected along a 1,200-km mosaic of coastal upwelling-driven acidification of the California Current System, Pespeni et al. combined (1) sequencing across the transcriptome of the purple sea urchin, (2) growth measurements under experimental acidification, and (3) tests of frequency shifts in 19,493 polymorphisms during development, while detecting in the process "the widespread occurrence of genetic variation to tolerate ocean acidification."
The eleven researchers report that although larval development and morphology showed little response to elevated CO2, they found "substantial allelic change in 40 functional classes of proteins involving hundreds of loci." More particularly, they state that "pronounced genetic changes, including excess amino acid replacements, were detected in all populations and occurred in genes for biomineralization, lipid metabolism, and ion homeostasis - gene classes that build skeletons and interact in pH regulation," while noting that "such genetic change represents a neglected and important impact of ocean acidification that may influence populations that show few outward signs of response to acidification."
In considering all of the above, the researchers conclude "our results demonstrate the capacity for rapid evolution in the face of ocean acidification and show that standing genetic variation could be a reservoir of resilience [italics added] to climate change in this coastal upwelling ecosystem."