On an island
These atolls are both in the Marshall Islands.
No, the word atolls is the plural form for the singular noun atoll. Example:There are a number of atolls on the coast near my home.
Atolls are formed first as a reef that fringes a volcanic island. The two largest atolls are Suvadiva in the Maldives Island and Kwajalein in the Marshall Islands.
Bikini and Eniwetok atolls are US protectorates in the Marshal Islands of the pacific. They are considered legally US property.
crustal sinking
crustal sinking
Atolls
Atolls, Coral reefs, and lagoons Source: World Geography textbook
Atolls don't float to start with. There is land, the remnants of former volcanic islands, beneath them. The lagoon in the centre is not connected to the sea.
lagoon
atolls