Coral Bleaching By Jaeson Vargas

According to the National Ocean Service, coral bleaching is when coral reefs lose their color after losing their symbiotic algae. Corals and algae depend on each other in a mutual relationship. The algae gives coral the majority of their nutrients and their pigmentation, in return corals give algae shelter inside of their polyps. The polyps need the algae for food, and fish in turn get their food from the polyps. When coral reefs become stressed by external factors like light, temperature, and nutrition intake, they begin to lose their color and turn white, eventually dying in the process.

Coral bleaching affects the entire reef ecosystem.
What causes coral bleaching?

Global Warming

The leading cause for coral bleaching around the world is global warming. Studies have shown that ocean waters have gradually increased in temperature over the past several decades. When the water becomes too warm, the coral reefs push out all of the algae that gives them their food. The warm water offsets the entire underwater food chain. Corals depend on algae, smaller fish feed off the corals, when the fish have nothing to feed on they die out or migrate, and predatory species like eels and sharks are forced to move as well. Thus, if all the reefs were to die out, the entire fish ecosystem crumbles.

Water Pollution

Another leading cause for coral bleaching is pollution in ocean water. Many loose sediments with harmful toxins cause algae to leave coral polyps. Other trash items have harmful chemicals that inflict the same effects. Trash items made of plastic often affect fish that are a vital part of the coral reef ecosystem.

What can be done?

According to studies conducted by the United Nations, if current temperature trends were to continue, it could result in losing 95% of the world's coral reefs.The best approach to stopping coral bleaching would be to lower global ocean water temperatures. In order to do that, there are several things that can be done. Lowering greenhouse gas emissions should be the primary goal. Fossil fuels from cars highly contribute to rise in global temperature. Another way would be to reduce pollutants making its way into reefs. Loose trash and sediments carry toxic fertilizers that kills symbiotic algae. Lastly, making an active effort in improving water quality by monitoring trash and pollutants will help prevent coral reef stress.

Created By
Jaeson Vargas


Created with images by pvandyke3 - "Porites lobata bleach 1" • oliver.dodd - "bleached" • Derek Keats - "Bleached area of a coral that has been killed by a crown of thorns starfish, Fiji" • q.phia - "vivian's reef, wakatobi, 2015 (70)" • pvandyke3 - "Pocillopora meandrina bleach 1" • pvandyke3 - "Montipora capitata bleached" • SarahDepper - "Staghorn Coral (with evidence of Coral bleaching :-( )" • Hans - "reef coral reef sponges aquarium underwater"

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