Heavier isotopes tend to be left behind when water evaporates from the ocean surfaces, the remaining ocean water becomes progressively enriched in oxygen 18.
当水从海洋表面蒸发时，往往会留下较重的同位素，所以剩余的海水会逐渐富含氧18这种同位素。
2
Most hydrogen and oxygen atoms in water are stable, but traces of both elements are also present as heavier isotopes.
在水中大多数氢原子和氧原子是稳定的，但这两个元素也有微量以较重的同位素形式存在。
3
By measuring the proportion of heavier hydrogen and oxygenisotopes along a strand of hair, scientists can construct a geographic timeline.