Coral Reefs in Crisis
Today’s corals are descended from species that lived about 240 million years ago. Reef-like structures have existed on Earth for at least 200 million years. But coral reefs—corals and the organisms that thrive in their shelter—are now in great danger. Warmer waters, caused by human-induced climate change, can kill many corals through a process called coral bleaching. Pollution is hurting the corals and other marine life in the reefs. Overfishing robs coral reefs of marine life, upsetting the delicate ecological balance. Blast fishing—using dynamite to bring dead fish to the surface—destroys the reef structures. Even the bump of a boat or the simple touch of a snorkeling diver can harm the delicate corals.
Scientific name: Gorgonia flabellum
Common name: Venus sea fan
Size: up to 2 meters wide
Diet: zooplankton (animal plankton)
Habitat: Caribbean Sea, Gulf of Mexico, and western Atlantic around Florida, between 1 m and 10 m deep
Characteristics: colorful branching trees or fans; the polyps are tube-shaped animals
Most corals are:
herbivores (organisms that eat plants)
carnivores (organisms that eat animals)
omnivores (organisms that eat plants and animals)
Correct!
Many coral species use stinging cells in their tentacles to catch small fishes and zooplankton (tiny, drifting animals), which they then eat.
Coral polyps can obtain their energy and nutrients in other ways too. Some of it comes from dinoflagellate algae that live inside them, converting sunlight into energy. And some species filter food out of the water to eat it, including bacteria and phytoplankton, or tiny, drifting plantlike organisms.
Corals are alive.
Fact
Corals are made up of small animals called coral polyps. Most coral species have tiny, colorful organisms called dinoflagellate algae living inside them that convert sunlight into energy, helping feed the coral polyps. The white structures you sometimes find on the beach are the skeletons of dead coral.