🐾 Coral Reef

Coral Reef

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Scientific name: Class Anthozoa (order Scleractinia)
Family & relatives: Corals are animals related to jellyfish and sea anemones; each reef is built by tiny animals called polyps.
How to spot it: A coral reef looks like a colorful underwater garden of branching, boulder, and fan-shaped stony structures teeming with fish.

Size: A single polyp is tiny, but reefs join together into huge structures; the Great Barrier Reef stretches over 1,400 miles.
Weight: Coral reefs are made of countless tons of limestone slowly built by generations of polyps.
Body & adaptations: Each polyp is a soft, tube-shaped animal with a ring of stinging tentacles and a stony cup it builds around itself.
Top speed: Coral polyps stay fixed in place, but a reef grows very slowly, often less than an inch a year.
Strength: Together, tiny polyps build the largest living structures on Earth, big enough to be seen from space.
Senses: Coral polyps have no eyes or brain but can sense light, touch, and chemicals in the water.
Growing up: Coral larvae float in the water, settle on hard surfaces, and grow into polyps that copy themselves to form a colony.

Habitat: Reef-building corals live in warm, clear, shallow, sunny tropical seas.
Where in the world: Coral reefs grow in tropical oceans around the world, especially in the Indo-Pacific and Caribbean.
Territory: Corals compete for space and sunlight, and some sting or overgrow neighbors to claim their spot on the reef.

Diet: Coral feeds in two ways: tiny algae living inside it make food from sunlight, and at night its tentacles catch drifting plankton.
Favorite foods: Corals get most of their energy from their algae partners and also eat plankton and tiny floating particles.
How it hunts: At night, polyps spread their stinging tentacles to grab tiny plankton drifting past.

How it moves: Adult coral cannot move, but its young larvae swim and drift before settling down for life.
When it is active: Many corals pull in their tentacles by day and open them to feed at night.
Family life: Coral polyps live together in colonies of thousands, sharing tissue and building the reef as one community.
How it talks: Corals release chemical cues into the water, and many spawn all at once on the same nights, cued by the moon.
Babies: Corals reproduce by budding new polyps and by releasing eggs and sperm into the water during mass spawning events.

Role in nature: Coral reefs are home to about a quarter of all sea life and protect coastlines from storm waves.
Conservation: Reefs are threatened by coral bleaching from warming seas, pollution, and acidification, making them one of the most at-risk ecosystems.
Dangers: Reefs are harmed by warming water, hungry crown-of-thorns starfish, storms, and human damage.

How long it lives: Individual polyps live for years, but a coral colony can live for hundreds of years and a reef for thousands.
In our culture: Coral reefs draw divers and snorkelers from around the world and are treasured for their beauty.
Where to see it: Explore coral reefs by snorkeling or diving in tropical seas, or see them in large public aquariums.
Fun fact: The Great Barrier Reef is the largest living structure on Earth and can be seen from space.

Video: Pixabay · Photos: Wikimedia Commons & Pixabay