atolls
Ring-shaped reef islands
Atolls are ring-shaped coral islands or chains of islands encircling a lagoon.
They form when coral grows around a volcanic island that later sinks beneath the sea, leaving the reef structure behind.
Atolls are found primarily in tropical Pacific and Indian Ocean waters: The Maldives consist almost entirely of low-lying atolls.
Marine skeletal formation
- reefUnderwater rock or coral formation
- volcanicOf fiery mountain origin
- subsidenceGradual ground sinking
- fringingAdding decorative border
barrier · ring-shaped · lagoon · Darwin · seamount · hotspot · plate tectonics · erosion
Chain of scattered islands
- isletVery small land mass
- caySmall coral island
- MaldivesIndian Ocean archipelago nation
- Marshall IslandsPacific island republic
Kiribati · Bikini · Midway · Palmyra · Christmas Island · Polynesia · Micronesia · Pacific
Of hot, humid regions
- low-lyingNear the ground
- sea level riseIncreasing ocean surface height
- floodingOverwhelming water accumulation
- storm surgeWind-driven coastal flooding
cyclone · erosion · vulnerable · drought · coconut palm · adaptation · habitable · uninhabited
Surrounded and sealed within
- shallowWithout much depth
- turquoiseBlue-green opaque gemstone
- brackishMildly salty water
- tidalOf sea rhythms
pass · channel · anchorage · sheltered · sandbar · pinnacle · circulation · flushing
Range of life forms
- coral reefCalcium carbonate marine ecosystem
- sea turtlesOcean-dwelling shelled reptiles
- giant clamsMassive tropical reef bivalves
- manta raysLarge flat cartilaginous fish
reef sharks · parrotfish · seabirds · coconut crabs · nesting · spawning · marine sanctuary · endangered
coral
Marine skeletal formation
- reefUnderwater rock or coral formation
- volcanicOf fiery mountain origin
- subsidenceGradual ground sinking
fringing · barrier · ring-shaped · lagoon · Darwin · seamount · hotspot · plate tectonics · erosion · uplift
archipelago
Chain of scattered islands
Marshall Islands · Kiribati · Bikini · Midway · Palmyra · Christmas Island · Polynesia · Micronesia · Pacific · Indian Ocean
tropical
Of hot, humid regions
- low-lyingNear the ground
- sea level riseIncreasing ocean surface height
- floodingOverwhelming water accumulation
storm surge · cyclone · erosion · vulnerable · drought · coconut palm · adaptation · habitable · uninhabited · remote
enclosed
Surrounded and sealed within
tidal · pass · channel · anchorage · sheltered · sandbar · pinnacle · circulation · flushing · sedimentation
biodiversity
Range of life forms
- coral reefCalcium carbonate marine ecosystem
- sea turtlesOcean-dwelling shelled reptiles
- giant clamsMassive tropical reef bivalves
manta rays · reef sharks · parrotfish · seabirds · coconut crabs · nesting · spawning · marine sanctuary · endangered · bleaching
- Indian Ocean IslandsMaldives, Rodrigues, Christmas Island, coral islands, islands
- islandsisland, isle, isles, islet, islets
- ecosystemsrainforest, forest, desert, jungle, ocean
- Indian OceanArabian Sea, Bay of Bengal, Persian Gulf, Red Sea, Andaman Sea
- landformsmountain, cliff, valley, volcano, mountain ridge
- OceaniaFiji, New Zealand, Australia, Samoa, Tonga
atollsmainlands
Principal continuous land areas
continents · volcanic islands · mountain ranges · land bridges · peninsulas
atollsmountain peaks
Highest elevations of ranges
volcanic peaks · highlands · mountain ranges · mountainous terrain · alpine regions
- Bikini AtollIrradiated Pacific coral ring
- coral atollsRing-shaped island formations