Coral - Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically live in compact colonies of many identical individual polyps. Corals species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton
Runoff - Surface runoff is the flow of water that occurs when excess stormwater, meltwater, or other sources flow over the Earth's surface.
Symbiotic - type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasitic.
Zooxanthellae - single-celled algae photosynthesize and pass some of the food they make from the sun’s energy to their hosts, and in exchange the coral animal gives nutrients to the algae.
Polyp - The polyp is like a tin can open at just one end: the open end has a mouth surrounded by a ring of tentacles. The tentacles have stinging cells, called nematocysts, that allow the coral polyp to capture small organisms that swim too close.
Colony - a community of animals or plants of one kind living close together or forming a physically connected structure.