Coral Bleaching: Potential Mechanisms and Observed Adaptations :: Sea Coral Corals Ecosystem Papers

Coral Bleaching Potential Mechanisms and Observed AdaptationsCoral reefs be the most biologically diverse marine ecosystems. Driving this diversity ar cnidarian precious precious corals which be obligate mutualistic symbioses between coral animals and dinoflagellate alga of the genus symbiodinium. These algae are commonly called zooxanthellae. This symbiosis between heterotrophic hordes and photosynthetic symbionts allows coral to thrive in nutrient poor seas and deposit calcium change to build reefs (Toller et al. 2001, 348).Coral bleaching occurs when there is a loss of zooxanthellae from their coral host. This is tended to(p) by loss of a corals general color that may or may not be detectable to the human eye. Bleaching can pass by to coral death when prolonged, although links between bleaching and subsequent coral recovery or death are not well known. Causes of bleaching have been observe to include salinity, exposure to air, and sedimentation. The primary reason s cited to grow most instances of coral bleaching are increased sea temperatures and solar radiation sickness. These two factors have been observe to cause the most damage in combination (Fitt et al. 2001, 51).The two types of bleaching that result from existence damage or disturbance are algal-stress bleaching and animal-stress bleaching. Algal-stress bleaching is characterized by expulsion of soulfulness zooxanthellae from a host cell. Animal-stress bleaching is characterized by host cell detachment, which is expulsion of zooxanthellae from the coral animal along with the host cell they occupy. Radiation and temperature induced animal-stress bleaching and host cell detachment have not been observed in the study at current sea temperatures. This type of bleaching has only been observed low laboratory conditions (Fitt et al. 2001, 55). A third type of bleaching, physiological bleaching, occurs in an light coral-zooxanthellae holobiont as a method of shedding excess zoo xanthellae from host cells. Zooxanthellae denseness within host cells varies seasonally in this manner. Maximum zooxanthellae density is observed to occur during the coolest season with the lowest solar radiation. The minimum density is observed to occur at the end of the warmest season with the highest solar radiation (Fitt et al. 2001, 54).The temperature at which coral bleaching occurs has been observed to be from 30 to 34 degrees Celsius (Ralph et al. 2001, 163). Solar radiation exacerbates bleaching in this temperature range and can also cause bleaching at normal temperatures when at sufficient intensity.