How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic

The Transgenerational Plasticity of the Purple Sea Urchin

Paper Reviewed
Wong, J.M., Johnson, K.M., Kelly, M.W. and Hofmann, G.E. 2018. Transcriptomics reveal transgenerational effects in purple sea urchin embryos: Adult acclimation to upwelling conditions alters the response of their progeny to differential pCO2 levels. Molecular Ecology 27: 1120-1137.

Transgenerational plasticity (TP) is an adaptive mechanism by which parents can influence the phenotype of their offspring to be better suited to cope with abiotic stresses and/or changes in their environment. TP is postulated as a means by which marine organisms can successfully respond to future predictions of ocean acidification, reducing concerns of species' collapse-and possible extinction-as a result of projected declines in seawater pH levels. Nevertheless, TP research is limited, and more studies into this topic should help scientists better understand its potential as an adaptive mechanism to environmental stress.

Adding some insight on the subject, Wong et al. (2018) recently designed an experiment to examine the TP of the purple sea urchin (Strongylocentrotus purpuratus). For their study, the four researchers collected adult urchins from a subtidal rocky reef near Goleta, California, which they then transported to a laboratory at the Marine Science Institute at the University of California Santa Barbara and conditioned for approximately 4.5 months under one of two treatment levels. The two treatments included (1) ~400 µatm pCO2 seawater maintained at 17°C and (2) ~1100 µatm pCO2 seawater maintained at 14°C.

At the end of the conditioning period, spawning was induced and female eggs from urchins in both treatments were fertilized by a single male. Fertilized eggs from the females in each initial treatment were then reared through the early developmental stages under either low (~400 µatm) or high (~1100 µatm) pCO2 levels at a constant temperature of ~15°C. Then, at approximately 30 hours postfertilization, the researchers measured egg diameter and conducted RNA-seq and comparative transcriptomic analyses during the gastrula stage.

In presenting their findings, Wong et al. report that offspring of mothers conditioned to the high pCO2 treatment were larger in size at the gastrula stage than those whose mothers were conditioned in the low pCO2 treatment. RNA sequencing and transcriptome analyses revealed that the "differential conditioning of the adults had an effect on the gene expression patterns of the progeny," with the authors adding that their study "provides evidence that parental experience during gametogenesis can impact the F1 generation via TP and suggests that urchin populations can adjust to changing ocean conditions faster than adaptation can functionally occur." Consequently, it would appear that nature is fully equipped to deal with whatever challenges it faces, including predictions of future ocean acidification.

Posted 16 June 2018