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Ocean Acidification: Not One Thing Or Another

June 24, 2013 | A version of this story appeared in Volume 91, Issue 25

The proper way of responding to a letter such as that from Jerry L. Krause on the issue of ocean acidification is difficult (C&EN, May 13, page 2). Perhaps it’s best to mention simple things. Krause points out that the acid concept is relatively new, and electrochemical methods of measuring pH date back only to 1906. He asks how it is possible, then, that we have measurements of pH going back more than 250 years.

As one who follows such things, I know there are biogeochemical proxies for pH including, among others, boron isotope ratios of foraminiferal carbonate, which can take us back much further than 250 years. Krause tries to minimize the measured decrease of pH in the oceans from 8.2 to 8.1 as not being precise. He can be assured that pH variations with location and time have been measured well enough by both proxy and more recent instrumental methods to make such a statement meaningful. In addition, we have observed the expected decrease in the amounts of aragonite from which many sea animals build their shells.

I agree with Krause that many factors are stressing the productivity of Pacific Northwest fisheries. Indeed, this is a classic case of not one thing or another—but rather one thing and another and yet another and so on. But each “another” counts, and for the fishery to flourish each must be dealt with, including acidification, the effects of which are global.

Joshua Halpern
Washington, D.C.


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