The addition of carbon dioxide into the water causes carbonates to break down into bicarbonates, inhibiting the growth of shells in shellfish, corals and other ocean life critical to the fisheries, said Robert J. Foy, director of the NOAA Fisheries Science Center in Kodiak.

In the case of crab larvae, which come initially to near the surface of the ocean after being released by the crab, studies have shown that increased acidity in the ocean has a negative affect on the larvae, Foy told participants in ComFish 2008 on March 22. “We are now trying to determine how this affects survival rates in the wild,” he said.

The removal of carbonates also affects shell formation of plankton, cold water corals and other sea life critical to the ocean food chain. Pink salmon, for example, rely on pteropods for 45 percent of their diet. A 10 percent decrease in the pteropod population would result in a 20 percent drop in the weight of pink salmon, Foy said.

“We won't see animals dissolving on the beach; what we will see is recruitment failures,” he said.

Since the start of the industrial revolution, the highest concentration of manmade carbon dioxide has been in the North Atlantic Ocean, but since the vertical circulation of the ocean starts in the North Atlantic and comes up in the North Pacific, it is the North Pacific that will be affected first by removal of carbonates from the ecosystem, Foy said.

Carbon dioxide is both man-made and natural in the ocean. The man-made carbon dioxide is found mostly in the top layers of the ocean and is most concentrated in the North Atlantic.

Natural carbon dioxide is found in the deep layers of the ocean, but due to global circulation, it sinks in the North Atlantic and up-wells in the North Pacific. The combination of man-made carbon dioxide in the surface waters and carbon dioxide being up-welled makes the North Pacific ecosystem particularly susceptible to the effects of ocean acidification.

The Alaska Fisheries Science Center has been working with other climate change groups to study these changes in the ocean, but has been inhibited by the cost of such studies, Foy said.

“The scale to measure this is in the millions of dollars,” he said.

The critical issues of ocean acidification are now being studied on a worldwide basis.

The Ocean Acidification Network, an information network for the international scientific community, has scheduled its second symposium on the ocean in a high carbon dioxide level world for Oct. 6-9 in Monaco. Details on this symposium are at www.ocean-acidification.net.

NOAA's Pacific Marine Environmental Laboratory carbon dioxide program, located in Seattle, is conducting ocean carbon cycle research from ships and moorings in all of the major ocean basin areas, in cooperation with NOAA's Atlantic Oceanographic and Meteorological Laboratory. Its goal is to assess the ocean's role in controlling atmospheric carbon dioxide levels with a focus on observations of the exchange of carbon dioxide across the air-sea interface, and its eventual penetration into the waters of the deep ocean.

Scientists with NOAA's climate program office have noted that current models used to project future atmospheric carbon dioxide concentrations assume that the carbon cycle will continue to operate the same way it has in the recent past.

It has been suggested that long-term uptake and storage of carbon by the ocean may be reduced by climate change, resulting in an increased proportion of carbon dioxide remaining in the atmosphere.