Coral grubbs give off a gas that is lighter than air.This keeps the isles suspended in the sky, but can be a nuisance when attempting to construct buildings.

• 珊瑚虫会放出一种比空气还轻的气体，这种气体使诸岛悬浮于空中，但对于兴建楼房屋宇却又是阻碍不少。