Coral is divided into two main subtypes, hard and soft. These animals grow incredibly slowly, and in symbiosis with many other types of sealife.
There are around 6,000 types of Coral, and a few of the common ones are:
Algea that lives inside corals absorb much of the suns energy. As the oceans get warmer, some of the algea cannot survive leaving the coral exposed to the suns energy. Some coral are capable of producing a vibrant pigment which acts as sunscreen for them, this is why some coral looks fluorescent.
As Wikipedia states: Fluorescence serves a wide variety of functions in coral. Fluorescent proteins in corals may contribute to photosynthesis by converting otherwise unusable wavelengths of light into ones for which the coral's symbiotic algae are able to conduct photosynthesis. Also, the proteins may fluctuate in number as more or less light becomes available as a means of photoacclimation. Similarly, these fluorescent proteins may possess antioxidant capacities to eliminate oxygen radicals produced by photosynthesis. Finally, through modulating photosynthesis, the fluorescent proteins may also serve as a means of regulating the activity of the coral's photosynthetic algal symbionts,
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