Oceans acidification and arctic carbonates

大气中二氧化碳的积聚被指责为全球变暖的罪魁祸首，但在海洋中也有同样令人担忧的后果：海洋生物栖息地的迅速酸化。大气中二氧化碳的积累确实伴随着海洋中同样大量的二氧化碳积累。二氧化碳一旦溶解，就会分解成一种活性更强的化合物，与氢结合形成碳酸。海洋中的碳酸给构成坚硬碳酸钙骨架的生物(例如珊瑚)带来了巨大的压力，其中许多以微观形式存在，构成了海洋食物链的基础。大气中的二氧化碳浓度仅比工业化前的数值高出35%，但海洋酸化正在顺利进行。我们将研究古代海洋对大气二氧化碳显著增加的反应，这种增加发生在3.25亿到2.5亿年前，当时二氧化碳浓度上升了5到10倍于现代的数值。我们将调查海洋酸度的增加是否导致分泌碳酸钙的动植物逐渐灭绝。这一现象最终导致了地球上最大规模的物种灭绝，当时95%的硬壳生物已经消失。我们将在加拿大北极研究这一现象，在那里，无植被山脉的绝佳暴露为此类研究提供了有利条件。

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.