CENTRED ON CORAL
• Grow into coral reefs
• Live within an exoskeleton cup (or calyx), produced as the coral secretes calcium carbonate to stick to the ground and also to its polyp friends in its colony.
• Polyps are interconnected via a system of gastrovascular canals that allow them to share nutrients and zooxanthellae. These canals run through a very thin tissue on the surface of the coral
colony. These tissues can be easily damaged.
CORALS ARE VITAL!
• Coral reefs provide goods and services worth an
estimated SGD375 billion each year.
• Coral reefs protect shorelines from wave action and prevent erosion, property damage and loss of life. Reefs also protect the highly productive wetlands along the coast, as well as ports and harbours and the economies they support.
• Globally, half a billion people are estimated to live within 100 kilometres of a coral reef and benefit from its production and protection.
• Do not produce a rigid calcium carbonate skeleton and do not form reefs, though they may be present
in a reef ecosystem.
• Can often appear to look like plants, as they bend and sway in the
• Are also very sensitive to touch and
easily damaged by careless divers
1 Coral is an animal. They eat plankton and other small microbes, catching them with their tentacles.
2 Individual coral polyps grow and live together to form colonies.
3 Coral polyps have a symbiotic relationship with an algae called zooxanthellae. The coral provides a home for the zooxanthellae. The polyps breathe in oxygen and breathe out carbon dioxide and water, which the zooxanthellae photosynthesise, producing nutrients that, in turn, the coral polyps use as food.
4 Growth rates vary between species, but is generally between 0.3 to 2 centimetres per year for “massive” corals, and up to 10 centimetres per year for “branching” corals.
5 It can take up to 10,000 years for a coral reef to develop. Depending on their size, barrier reefs and atolls can take from 100,000 to 30,000,000 years to fully form.
6 Coral reefs support more species per unit area than any other marine environment.
7 Scientists estimate that there may be another 1 to 8 million undiscovered species of organisms living in and around reefs.
8 Corals are most productive at less than 27 metres deep, but some deep-water species have been found at around 2,000 metres.
9 Coral reefs cover less than 1% of the surface of the planet.
Touching a hard coral can stop the polyps being able to communicate and share nutrients.