Coral Bleaching

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Coral bleaching is an occurrence that happens when the environment is inhabitable for the coral to live in.[1] This happens when the corals are stressed because of their conditions. Light, changes in temperature, and nutrients can stress the coral and this causes them to expel the algae they use for nutrition, to die. This causes the coral to turn a ghostly white color.

Causes of coral bleaching

An infograph from NOAA.
NOAA: infograph from NOAA [Coral Bleaching].

There are a few causes of coral bleaching. The main thing is the abnormal ocean temperatures. These higher than normal ocean temperatures are due to the warming of the Earth or when the water is too warm, the coral become extremely stressed. [1] They then expel their nutrients, algae, and die because they end up starving to death. Other reasons why the coral are dying is due to human pollution and sometimes low water levels. The pollution is caused by runoff from storms and this can bleach the coral closest to the shore. Low water levels can cause the coral to become exposed to the elements and die. Ocean acidification can also cause this bleaching. The ocean absorbs the carbon dioxide from the air and it effects the ocean. As these levels rise, it affects the animals and plants that live in the ocean. As carbon dioxide increases, the ocean pH decreases and becomes more acidic.


The bleaching and death of the coral is preventable if people are aware of the reasons that cause it. Scientist can do more research and people can be more cautious of what they do and how it affects the environment. Pollution and runoff from storms can affect the coral. Coral near the coastline and in the middle of the Pacific Ocean are the ones most affected. The chemicals from fertilizers and cars get into the ocean and affect things there.[2] People can become more aware of what they use on their lawns and properties. Another action people can do is raise awareness on this growing problem.

In Hawaii, they are having awareness events that inform people about this problem called Bleachapalooza. [2] This was a statewide event where volunteers went into the water and reported on the status of the coral. The volunteers also went into the water and helped spot the areas where the coral was bleached. Events like this can help people become more informed on this issue.

Another way the coral can be saved is by investing in scientific research. There are scientists who have been studying the coral and have concluded that there are ways that the coral can be saved. They have tested the coral and concluded that by feeding them zooplankton and phosphorus, the corals’ resilience can be increased. However, other nutrients the coral were given made the bleaching worse.

Current status of coral

A picture of bleached coral from Islamorada, Florida in 2014.
USGS: A picture of bleached coral from Islamorada, Florida in 2014 [USGS Coral Bleaching].

Currently, coral is suffering greatly, especially the coral off of the coasts of Hawaii. As of November 2015, the most damage is from the coasts of Mexico across the Pacific Ocean to Australia. Other regions with bleaching is off the coast of western Africa towards North America. [3] Most of the bleaching is around the tropical latitudes, where the water is the warmest. The warm temperatures are causing the coral to become stressed and then die. This, ocean acidification, and pollution are killing the coral. As the pH levels change and chemicals pollute the ocean, the more the bleaching will occur.

Bleaching in Hawaii

NOAA has reported in October 2015, that this year has had the world’s third worst bleaching event.[4] This is expected to get worse as global warming becomes a bigger issue. As the waters become warmer, the coral will suffer and continue to die. Once they die, they cannot come back. The coral are also suffering in other areas like the Great Barrier Reef and some coastal regions. The scientist predict that it will get worse as time goes on. They are trying to find preventative measures to help keep the coral alive.

See also

Other closely related articles in this wiki include:


  1. 1.0 1.1 US Department of Commerce, N. O. and A. A. (2015, February 17). What is coral bleaching? Retrieved September 18, 2015. NOAA Ocean Service Facts
  2. 2.0 2.1 Thayer, M. (2015, October 6). Bleached coral found in Maalaea Harbor - | News, Sports, Jobs, Visitor’s Information - The Maui News. Retrieved October 7, 2015, from Maui News
  3. NOAA. (2015, November 16). Current Operational Coral Bleaching HotSpot Charts - Office of Satellite and Product Operations. Retrieved November 17, 2015, from
  4. Belva, K. (2015, October 8). NOAA declares third ever global coral bleaching event. Retrieved October 19, 2015, from NOAA

External links