Oceans acidification and arctic carbonates

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The buildup of carbon dioxide in the atmosphere, blamed for global warming, has an equally alarming offspring in the oceans: the rapid acidification of marine habitats. The accumulation of atmospheric carbon dioxide is indeed accompanied by an equally large buildup of carbon dioxide in the ocean. Once dissolved, carbon dioxide breaks into a more reactive compound that combines with hydrogen to form carbonic acid. Carbonic acid in the oceans puts enormous pressure on organisms that build a hard calcium carbonate skeleton (for example, corals), many of which exist in microscopic forms and constitute the base of the marine food chain. Carbon dioxide concentration in the atmosphere is only 35% above pre-industrial values, and yet ocean acidification is well underway. We will study the response of ancient oceans to a far more significant increase in atmospheric carbon dioxide which occurred between 325 to 250 million years ago when concentrations rose 5 to 10 times the modern values. We will investigate whether it is the associated increase in ocean acidity that contributed to a progressive eradication of calcium carbonate-secreting animals and plants. This phenomenon culminated in the largest mass extinction on Earth, when 95% of hard-shelled organisms had disappeared. We will study this phenomenon in the Canadian Arctic where the superb exposures of vegetation-free mountains lend themselves to such research.