Some shellfish species are adapting better to increasing ocean acidification, according to a new study by Simon Fraser University researchers published today by the Public Library of Science.

Ocean acidification, caused by the absorption or atmospheric carbon dioxide, is widely believed to threaten ocean biodiversity and productivity. This study addresses one of the fundamental questions about the future of biodiversity under climate change: will populations be able to adapt via evolution?

“We measured the genetic variation in two species of marine animals in British Columbia – red sea urchins and blue mussels – and found they differ markedly in their potential ability to adapt,” says SFU biology graduate student Jennifer Sunday.

“The difference occurred because the sea urchins have more variable developmental responses at high CO2 – some sea urchins appear to develop faster, and others slower, in the increased acidity,” explains Sunday. “In contrast, mussels have very little natural, genetic variation in early development and thus are predicted to take longer to adapt.”

For the study, SFU and UBC researchers raised thousands of sea urchin and mussel larvae in both acidified water expected for the year 2100 (pH 7.9) and in regular seawater (pH 8.3). They then measured the larvae’s developmental responses and used quantitative genetics to calculate the genetic variation and heritability.

Initial estimates had wide confidence intervals, but researchers were still able to detect much greater genetic and phenotypic variation in sea urchins compared to mussels.

But there are still some unknowns as the study focused on a narrow period in the larvae’s development and can’t conclusively say sea urchins will thrive while mussels won’t. Instead, the findings indicate that species in general stand to differ in how quickly they can adapt.

“Despite remaining unknowns, this research is a key step toward predicting the winners and losers in our quickly changing oceans,” says Sunday. “Species with greater potential to adapt may become key natural resource species of the future, and the process could be sped up in an aquaculture setting using selective breeding.”

British Columbia’s shellfish industry is already taking precautions against future ocean acidification, says Sunday. She also warns that fish have been shown to lose key sensory behaviours relating to their sense of smell and sound in acidified waters. If B.C. fish are affected similarly, the PhD student says the consequences could be “catastrophic” and adaptation may be key.

Sunday collaborated on the paper with SFU biology professor Michael Hart and colleagues from the University of B.C.

Contact:
Jennifer Sunday, SFU Biology, sunday@sfu.ca, 604.789.1997 (cell)
Dixon Tam, SFU PAMR, dixont@sfu.ca, 778.782.8742

Simon Fraser University News, 9 August 2011. Article.