It might surprise you to learn that coral is an animal. It is a polyp (an invertebrate related to anemones and jellyfish) that secretes a hard layer of calcium carbonate in order to form its skeleton. Living symbiotically within the tissue of each polyp are cells of a type of dinoflagellate (micro alga) called zooxanthellae, which is what gives corals their bright colours.
Zooxanthellae provide around 90% of the nutrients for the host polyp, in the form of sugars and other organic molecules, produced via photosynthesis. Bleaching occurs when zooxanthellae leave or are expelled from the coral due to two different effects.
Your organisation does not have access to this article.
Sign up today to give your students the edge they need to achieve their best grades with subject expertise
Subscribe
