The oxygenisotope ratio of the ocean changes as a great deal of water is withdrawn from it by evaporation and is precipitated as snow to form glacial ice.
随着大量的水通过蒸发被抽离，并以雪的形式沉淀形成冰川冰，海洋中氧同位素的比率就发生了变化。
2
Almost all the oxygen in water is oxygen 16, but a few molecules out of every thousand incorporate the heavier isotope 18.
水中几乎所有的氧都是氧16，但每一千个分子中就有几个含有较重的同位素18。
3
When the air was warm, vapor containing the heavier isotope, oxygen-18, condensed and formed precipitation, in the form of snow, more readily than did vapor containing oxygen-16.