When we burn fossil fuels, we are not just putting carbon dioxide into the atmosphere. A lot of it goes into the sea. There, carbon dioxide turns into carbonic acid. And that turns ocean water corrosive, particularly to shellfish and corals.
Biologists are now coming to realize that rising acid levels in the ocean can affect many other forms of sea life as well.
Visit Moss Landing, Calif., in the spring and at first blush it seems marine life is flourishing. Sea lions, weighing in at 600 pounds or more, jostle for space and spar with one another as they try to cram themselves onto docks that groan under their weight.
Marine biologist Eric Pane looks on approvingly at what seems to be part of a Pacific success story. Up and down the coast, biologists see healthy populations of marine mammals, fish and other wildlife.
But as we cross the street and head into his laboratory at the Monterey Bay Aquarium Research Institute, Pane’s outlook about the future of life in the sea takes a dark turn. His budding career as a marine biologist is framed by an ominous trend: civilization is venting carbon dioxide from tailpipes, smokestacks and chimneys at a prodigious rate.
“And at least a third of it so far, has actually ended up in our oceans,” Pane says. “(That’s) sort of good and bad news because it has prevented more CO2 from accumulating in the atmosphere but it comes at a price. More CO2 in the ocean leads to it being acidified.”
Acidity is measured on the pH scale. Already, the oceans are a tenth of a unit more acidic. And by the end of the century, the pH is expected to change by half a unit. But don’t be fooled by these modest-sounding numbers.
“So we say ‘only’ — ‘only’ half a unit. What’s the big deal about that? Well, that’s a tripling of acidity,” Pane says. “That’s a three-fold increase.
That’s because the pH scale is logarithmic, so each unit increase actually represents a ten-fold increase in acidity.
Richard Harris, npr, 12 August 2009. Full article & audio.