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.
On an island
crustal sinking
crustal sinking
Atolls
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.
Oil is deposited in atolls in some regions of the Pacific through natural processes such as seepage from underground oil reservoirs, where oil rises to the surface and accumulates in the porous coral reefs and sands of atolls. This oil can also originate from oil spills or leaks from shipping vessels and other human activities. Over time, the oil can become trapped within the atoll's geological structures and persist in the environment.
lagoon
atolls
The opposite of an island (land completely surrounded by water) is a peninsula. A peninsula is a piece of land that is almost entirely surrounded by water but is connected to the mainland by a narrow strip of land.