Growing Ocean Acidity Problem Thins Shells of Ocean Creatures

[n2doc]

By Andrea Thompson, Senior Writer
posted: 08 March 2009 02:21 pm ET

Scientists have started to see some of the expected effects of Earth's increasing carbon dioxide burden: The shells of microscopic animals in the ocean are becoming thinner thanks to the ocean's absorption of some of that excess carbon dioxide, a new study shows.

The shells of those creatures studies are about one-third lighter.

As carbon dioxide from the burning of fossil fuels has accumulated in the atmosphere, some of it has been absorbed by the ocean. As the gas dissolves in the water, it forms a weak acid (the same kind that's in bubbly soft drinks), causing the ocean itself to become gradually more acidic.

As ocean water becomes more acidic, it also lowers the amount of calcium carbonate available to aquatic animals that use the mineral to build shells or skeletons, such as corals. These organisms can be important links in the marine food chain.

Scientists have predicted that the increase in ocean acidification could significantly reduce the ability of these creatures to build their casings, potentially devastating them and causing rippling effects through the ecosystem. But "until now the potential impact on ocean chemistry and marine life has been based on projections and models" and laboratory experiments, said leader of the new study, Will Howard of the Antarctic Climate & Ecosystems Cooperative Research Centre in Australia.

more:

http://www.livescience.com/environment/090308-acidification-shells.html