The diver re-surfaced after staying underwater for half an hour.

re-surfaced 由前缀 re-（表示"再次"）和动词 surface（浮出水面）组成，surface 本身由名词 surface（表面）转化而来。re-surfaced 字面意思是"再次浮出表面"，即"重新浮出水面"。