The Green Medium is an Emerald Award-winning, youth-run blog that seeks to innovate how we discuss and inform ourselves on environmental concerns.

Coral bleaching and its Impacts

We know that coral bleaching can be caused by the warmer waters, due to global warming and weather patterns. But what exactly is coral bleaching? And also how does it impact humans?

Coral bleaching occurs when a coral is stressed. Here are some factors that cause corals stress:

  • Extra-bright sunlight (so the depletion of the ozone layer affect them very much)
  • Water temperature outside of their livable range (both warm and cold water can stress corals)
  • Pollution and agricultural run-off
  • Change in water salinity
  • Sedimentation from undersea activities

When a coral is stressed, they expel the zooxanthellae* algae that they live in symbiosis. Zooxanthellae provides corals with food and is what gives the corals colors; thus, a coral will turn white if it expels the algae. Since reef-building corals are mainly dependent on zooxanthellae to provide food for them, they will become more vulnerable to diseases and die.

Steps toward death. Credit:

Why should we care? Shallow coral reefs are essential to fish habitat, meaning that both fishing and tourism-dependent countries rely on the existence of coral reefs to keep their economy stable. Coral reefs also protect the shores from large waves, storms, and floods. Moreover, scientists are trying to use corals to make new drugs to cure cancer, arthritis, and microbial infections.

One way to help support coral conservation is to reduce your carbon footprint by doing simple things like choosing to walk, bike, or take public transit instead of driving. You can also support forest conservation since trees reduce carbon dioxide in the air as well as agricultural run-off. You can also spread awareness or even adopt a coral reef [here].


*please refer to my previous article (link) for more information about corals



The decline of emperor penguins

Brief introduction to coral reefs and the individual polyp that make up their colony