The Environmental Protection Agency has asked scientists to send in information about how ocean acidification may be affecting ecosystems and new techniques for measuring the phenomenon. The move by the Obama Administration comes after long resistance on the issue by the Bush EPA.The Center for Biological Diversity threatened to sue EPA last year before the agency relented, agreeing to review the criteria for regulating the acidity of natural water bodies.
Under current rules, EPA designates ocean or freshwater areas as "impaired waters" under the Clean Water Act if the pH of the water is 0.2 units off naturally occurring levels. Scientists want EPA to review these rules for a number of reasons. There's evidence that marine ecosystems may be affected by change in pH of less than 0.2 units. In addition, a simple numerical limit may not be an adequate safeguard. Perhaps a better standard, says CBD's Miyoko Sakashita, would be one in which environmental factors, such as the biological health of a particular species in a marine ecosystem, would be used by regulators to set appropriate limits. Plus, there's new science coming out on the problem all the time.
"It's going to be tricky to set regulations for," says geochemist Ken Caldeira of the Carnegie Institution for Science in Palo Alto, California. Different organisms in the same ecosystem often have different levels of tolerance for acidic water, he points out; one reef's threshold may be different than another's.