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
When scientists did find multicellular organisms, they assumed that they'd sunk from oxygen-enriched waters.
而当科学家们确实在深海发现这种多细胞有机生物时，他们曾猜想这些生物是从富氧水域沉降而来的。
3
It is important to note that fire chemistry starts to change in oxygen-enriched environments.