A coral island or islands, consisting of a belt of coral reef, partly submerged, surrounding a central lagoon or depression; a lagoon island.
A circular reef that encloses a relatively shallow lagoon and extends from a very great depth to the sea surface. An atoll forms when an oceanic island ringed by a barrier reef sinks below sea level.
A ring of low coral islands surrounding a lagoon.
A massive coral growth on a submerged mountain range or volcano, common in the Indian and Pacific Oceans. The only English word derived from the Maldivian language, an atoll is a large coral reef, containing low inhabitable islands, encircling a sea water lagoon.
a ring-shaped coral reef that forms around a volcanic island.
A ringlike coral island and reef that nearly or entirely encloses a lagoon.
ring of coral islands and reefs surrounding a central lagoon.
A continuous or broken circle of coral reefs and low coral islands surrounding a central lagoon.
a closed loop of coral reef surrounding an open lagoon with no island inside
a type of coral reef that grows in the shape of a circle, enclosing or nearly enclosing a lagoon.
a circular, or horseshoe-shaped coral island surrounding a lagoon with one or more openings to the sea
a circular surrounding a lagoon, often not associated with any obvious land
a coral formation that grows during hundreds or thousands of years around a volcanic crater and stands out above the surface of the sea
a coral island encircling a lagoon like a ring
a group of coconut tree-fringed islets that sprout from the rim of a long-dead underwater volcano
a group of islands with a reef that nearly or entirely encloses a ring-like lagoon
a limestone cap - commonly bowl-shaped at the surface with a ring like ridge or reef enclosing a body of water or lagoon, which is surrounded by the open ocean
a low-lying island formed of coral reefs that have built up on the circular or oval rim of a submerged volcano
an annular reef formed around a subsiding volcanic island
an circular ring of coral that is above the water
an island formed from a coral reef that has grown on an eroded and submerged volcanic island
a reef surrounding a lagoon that has no central island, with passages through the reef to the sea
a ring- or horseshoe-shaped group of islands, surrounding a lagoon
a ring-shaped coral island surrounding a lagoon, always beautiful, and almost exclusively found in the South Pacific
a sunken volcanic ridge
a type of low, coral island found in the tropical ocean consisting of a coral-algal reef surrounding a central depression
a ring shaped coral reef that grows upward from a submerged volcanic peak and encloses a lagoon; may support low-lying islands composed of coral debris
Annular coral reef enclosing a lagoon which communicates or not with the open sea by one or more passes.
an island formed from a coral reef, sometimes circular or horseshoe-shaped, with a lagoon in the center
A region of DNA that is absent on the chromosome of an organism but absent from closely related organisms (i.e., the opposite of a genetic island). The loss of such genetic material may confer a distinctive phenotype. For example, absence of certain genes from E. coli enhances virulence.
circular, or near circular coral reef appearing as a low coral island or a ring of closely spaced coral islets encircling a shallow lagoon in which there is no pre-existing land, and surrounded by deep water of the open sea, formed above an underwater volcano. arometric pressure: a measure of the force exerted by the atmosphere used to forecast the weather.
An atoll is a ring (or partial ring) of coral that forms an island in an ocean or sea.
A horseshoe or circular array of islands, capping a coral reef system perched around an oceanic volcanic seamount and enclosing or nearly enclosing a lagoon.
Island surrounded by a coral reef.
A torus-shaped organic reef enclosing a lagoon in which there is no pre-existing land, and being surrounded by open sea.
a ring-shaped coral reef or string of coral islands, usually enclosing a shallow lagoon
A nearly circular island initally formed by a volcano, which eroded leaving a coral island consisting of a reef surrounding a lagoon.
A ring-shaped coral reef, often with low sandy islands, nearly or entirely surrounding a central lagoon.
A coral reef that develops around a circular reef surrounding a lagoon.