Can corals live at the bottom of the ocean?
The answer is…Yes! Scientists have discovered almost as many species of deep sea corals as they have of shallow water corals. These corals may exist as individual polyps or as reefs made of many different types of corals. Deep-sea corals are some of the oldest living organisms on Earth. One type of gold coral found in Hawaii was 2,742 years old. One species of black coral was found to be 4,265 years old! “Using radiocarbon dating techniques, dead Lophelia reefs in the Gulf of Mexico were estimated to be about 40,000 years old,” (oceanexplorer.noaa.gov).
Deep-sea corals are also called “cold water corals.” Corals can play an important role in deep-sea ecosystems. These corals provide a habitat for many groundfish (fish that live on the ocean floor), including black-bellied rosefish and the wreckfish.
Tropical shallow-water corals have a symbiotic algae called zooxanthellae, which are photosynthetic algae. This algae provides food for the coral polyps. Since the algae are photosynthetic, they need sunlight. Sunlight does not penetrate through the depths of ocean water, so zooxanthellae do not inhabit deep-sea corals. In order to eat, each coral polyp has tentacles that extend and allow it to sting and catch prey.