Southeast Asian Coral Reefs - Bleaching


Bleaching is one significant threat to the corals. Bleaching is a term that refers to a process that expels the photosynthetic algae from the corals' "stomachs" or polyps. This algae is called zooxanthellae. It is vital to the reef's life because it provides the coral with nutrients; it is also responsible for the color. The process is called bleaching because when the algae is ejected from the coral reef the animal loses its pigment. Zooxanthellae densities are continually changing; bleaching is really an extreme of what naturally happens. The detrimental exaggeration of the natural occurrence can be explained by the increasing temperature of the oceans which is accused to be a result of the "Greenhouse Effect," or global warming (Blackman and Hughes). Biological oceanographer Paul Falkowski and marine biologist Andrew Baker from the Wildlife Conservation Society study bleaching and why it occurs. Their explanations can be put in their simplest terms as such: the algae's membrane melts from the rise in temperature and, as a result, spits out an "oxygen species" directly into the reef. The animal, in turn, views this process as a threat and ejects the algae as a defense mechanism. Once the zooxanthellae are expelled the coral have nothing to feed off and die. Bleaching has been shown to cause up to 90% mortality rate of the affected corals. However, there is a catch. The reefs that are victims of bleaching have been found to be affected in patches, suggesting that there are several factors that affect the bleaching threshold. Not only that, but both bleached and non-bleached corals are often found right next to each other. These cases are numerous, and the variation and impact of factors (such as species or light) are still being heavily questioned, researched, and are vaguely understood.

Read more about this topic:  Southeast Asian Coral Reefs

Other articles related to "bleaching":

Blanqueador - History
... The earliest form of bleaching involved spreading fabrics and cloth out in a bleachfield to be whitened by the action of the sun and water ... Tennant first produced a solution of calcium hypochlorite, then solid calcium hypochlorite (bleaching powder) Louis Jacques Thénard first produced hydrogen peroxide in 1818 by reacting barium peroxide ... Hydrogen peroxide was first used for bleaching in 1882, but did not become commercially important until after 1930 ...
Blanqueador - Classes of Bleaches - Reducing Bleaches
... dithionite (also known as sodium hydrosulfite) is one of the most important reductive bleaching agents ... processes to eliminate excess dye, residual oxide, and unintended pigments and for bleaching wood pulp ... + NaHOCH2SO2 which is used in bleaching wood pulp, cotton, wool, leather and clay ...
Deinking Process - Bleaching
... If white paper is desired, bleaching uses peroxides or hydrosulfites to increase the brightness of the pulp ... The bleaching methods are similar for mechanical pulp, but the goal is to make the fiber brighter ...
... The bleaching process has been known for thousands of years, but the chemicals currently used for bleaching resulted from the work of several 18th century scientists ... is so ubiquitous that many people just call it "bleach", and calcium hypochlorite (bleaching powder) ... Oxidizing bleaching agents that do not contain chlorine most often are based on peroxides, such as hydrogen peroxide, sodium percarbonate and sodium perborate ...
Bleaching Of Wood Pulp - Bleaching Chemical Pulps - Hydrogen Peroxide
... Hydrogen peroxide is sometimes used with oxygen in the same bleaching stage and this is give the letter designation Op in bleaching sequences ... peroxide, so some improvement in the efficiency of peroxide bleaching can be achieved if the metal levels are controlled ...

Famous quotes containing the word bleaching:

    Worn down by the hoofs of millions of half-wild Texas cattle driven along it to the railheads in Kansas, the trail was a bare, brown, dusty strip hundreds of miles long, lined with the bleaching bones of longhorns and cow ponies. Here and there a broken-down chuck wagon or a small mound marking the grave of some cowhand buried by his partners “on the lone prairie” gave evidence to the hardships of the journey.
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