Atoll
a lake and some coral?
A body of water that is encircled by a coral reef is called a lagoon. A lagoon is usually shallow and is separated from the ocean by coral reefs, barrier islands, or sandbars.
Anatollis a ring-shaped coral reef including a coral rim that encircles a lagoon partially or completely.
A backreef is a lagoon found in a coral reef ecosystem.
A Barrier Reef. The barrier reefs grow parallel to the shore of an island and are separated from it by a deep lagoon.
Atoll
It's a Lagoon.
lagoon maybe?
poop
An encircling coral reef or sandbar can create a shallower area of water near an island, called a lagoon.
An atoll is a ring-shaped coral island or string of islands that surround a lagoon. Atolls typically form from volcanic islands that sink into the ocean, leaving a coral reef formation around the edge of the submerged island. The lagoon in the center of an atoll is often shallow and can support diverse marine life.
An atoll is a ring-shaped coral reef and features a lagoon. Some examples of atolls are the Bikini atoll, Tubbataha Reef and Lighthouse Reef.