translation.en: They plumb the depths down to 600 meters, in temperatures to one degree centigrade, and this is why you see them on the surface -- it's so cold down there.
translation.zh: 它们垂直下降可达600米，那里的温度仅1摄氏度， 这也是为什么会看到它们在海面的原因，那下面太冷了。