But Stillman and colleagues say those kinds of studies showing how species react in the short term are not enough to predict what our oceans will look like in the future. Marine scientists need new tools --including genetic surveys and experimental evolution studies -- to discover how organisms might adapt in the long run to acidification.
Surveying the variety in genes related to how organisms respond to acidification could reveal the pathways through which adaptation might occur. Experimental evolution studies, where a group of organisms is bred under controlled acidic conditions, mimic the natural selection process that would occur in nature over tens or hundreds of years.
The ideal experiment would be to follow "organisms over many generations, and to be able to look at what the genetic contribution is to how they respond to changes in their environment," Stillman said. "It would be similar to breeding studies that the biomedical community has been doing for a long time in animals like mice, but it's something that we don't typically do that often or that well with marine organisms."
The hotspots for studying adaptation to acidity, Stillman said, are places where there is a strong variability in acidity already, such as the California coast. Upwelling of deeper, more acidic water along the coast has already produced a range of responses to acidity in creatures such as sea urchins, he noted.
These pulses of very acidic water along the California coast could increase as runoff pollutants, such as fertilizer nutrients, contribute to a rise in carbon dioxide that acidifies upwelled water. As temperatures rise inland as a result of global climate change, Stillman said, "We're going to see more of those intense winds that cause the upwelling of that acidified water."
All of these factors
|Contact: Nan Broadbent|
San Francisco State University