Corals Glossary

bathymetry

water depth measured to the ocean floor from the water surface; the oceanic equivalent of topography.

calcification

the process by which corals extract calcium from seawater and create calcium carbonate.

cnidaria

an animal phylum characterized by stinging cells called nematocysts, that contains the stony (hard) corals, anemones, sea fans, sea pens, hydras, and jellyfish.

coral

a group of marine animals belonging to the phylum cnidaria, that exist as small sea anemone-like polyps, typically in colonies of many identical individuals; or the skeletal remains of coral polyps.

coral bleaching

the loss of color in corals due to stress-induced expulsion of symbiotic zooxanthellae algae.

coral polyp

a small individual coral animal with a tube-shaped body and a mouth surrounded by tentacles.

coral reef

aragonite (calcium carbonate) structure produced by corals and found in shallow, tropical marine waters.

molecular diffusion

the process by which carbon dioxide moves freely between air and sea. The exchange occurs in a film of water at the surface. Carbon dioxide travels wherever concentrations are lowest. If levels in the atmosphere are high, the gas goes into the ocean. If they are higher in the sea, as they have been for much of the past, the gas leaves the water and enters the air.

mutualism

symbiotic relationship in which both species benefit.

photosynthesis

the process by which plants make sugar from sunlight, water, and carbon dioxide.

respiration

process inside living cells in which sugars and oxygen are turned into carbon dioxide, water and energy.

salinity

the concentration of salts dissolved in water.

symbiosis

the close association of two different organisms, in which one or both benefit from the relationship.

watershed

area of land where all the water that is under it or drains off of it goes into the same place.

zooxanthellae

any of various yellow-green algae that live symbiotically within the cells of other organisms, such as reef-building coral polyps.