Coral bleaching – will global warming kill the reefs?
Glossary
coral reef. A marine ridge or mound that has been built up over thousands of years from limestone (calcium carbonate) deposited in the skeletons of coral polyps. The term coral reef is often used to refer to the entire ecosystem – the coral, the substrate built by the coral and the organisms that live in, on and around the reef. The geographical shape of a reef can also be part of the definition – fringing reefs, barrier reefs and atolls. For more information see How does a coral reef form? (CRC Reef Research Centre, Australia).
electromagnetic radiation. Electromagnetic radiation is simply energy which travels through space at about 300,000 kilometres per second – the speed of light. We imagine radiation moving like a wave. The distance between two adjacent wave crests is called a wavelength. The shorter the wavelength, the more energetic the radiation is said to be. Also, the shorter the wavelength, the greater the frequency of the radiation. Other than wavelength, frequency and energy there is no difference between a radio wave, an X-ray and the colour green. They all possess the same physical nature. For more information see Back to Basics: Electromagnetic radiation (Australian Academy of Science) and Electromagnetic Spectrum (NASA Goddard Space Flight Center, USA).
fluorescent pigment. A pigment that absorbs light (electromagnetic radiation) at one wavelength and emits it at a different wavelength. Usually the emitted light has a lower energy than the light absorbed by the pigment.
photosynthesis. The biochemical process in which green plants (and some microorganisms) use energy from light to synthesise carbohydrates from carbon dioxide and water. Photosynthesis can be shown as:
CO2 + H2O + energy→ [CH2O] + O2
plankton. Microscopic plants and animals that live near the surface of oceans and lakes.
ultraviolet (UV). A form of electromagnetic radiation. UV radiation has shorter wavelengths than visible light and it therefore carries more energy. It is divided into three broad categories: A, B and C. UV-A has the longest wavelength and is the least damaging form, although sufficient exposure will cause sunburn. UV-B damages proteins in unprotected organisms and can cause cancer, while UV-C is extremely dangerous because it can cause mutations in DNA.
Posted April 2003.