Contributing Monkie Sarah Backhouse
Published on April 24, 2008
When I first heard about ocean acidification wiping out most of the coral reefs by the end of the century, I was skeptical. For you novices, that’s the process whereby carbon dioxide from the air becomes carbonic acid, which in turn dissolves the calcium carbonate in coral. You keeping up? Then there were the supposed detrimental effects on coccolithophores (that’s a single-cell, carbonate-encased algae) in particular, the Emiliania huxleyi. Higher levels of acidity were thought to hinder “the algae’s ability to build the disks of carbonate that form its shell”. As if.
Well, it turns out my instincts were spot on. A new study led by scientists M. Debora Iglesias-Rodríguez of the National Oceanography Center at the University of Southampton and Paul Halloran, a graduate student at the University of Oxford, and published in the journal Science found the exact opposite to be true. Algae actually thrived and grew bigger in acidic water. The discrepancy can be attributed to differing methodologies: in the case of the former, acid was applied directly to the water; in the latter study it was applied indirectly “by bubbling carbon dioxide into the water”, a process closer to that found in nature. So, by lowering the pH, carbon dioxide in the water rose, kicking the algae’s “photosynthesis machinery” into high gear.
“It’s a really complex problem,” Dr. Iglesias-Rodríguez said, quoted by the New York Times. “You cannot look at calcification in isolation. You have to look at photosynthesis as well.” The lab findings coincide with real events in the ocean, “average mass of a coccolithophore increased 40 percent as ocean pH levels dropped”. Dr. Iglesias-Rodríguez stressed that this doesn’t negate ocean acidification or other impending ecological problems, rather “it points to how little data biologists currently have”.
But we knew that already, didn’t we?
(via the New York Times)