coralCoral Bleaching: Proof of Destructive Climate Change

by Gabbie Baillargeon

The classic image of a thriving reef full of life and color has begun to transform into a bleached white wasteland that is incapable of supporting life. Corals have gone from being the ocean’s lifeline to fighting for its own vitality, due to the onset of global warming. We have all heard the term “global warming” but not always speculated the drastic alterations that it has made to our planet. Corals are proof that global warming is taking place right under our noses. The mass bleaching events that have taken place since 1998 have exterminated 20 percent of the world’s reefs.

Why does coral bleaching occur?

Corals are invertebrates that are incredibly sensitive to temperature and pH changes. Coral Polyps settle in reefs and then construct hard, protective calcium carbonate exteriors. Corals have a unique symbiotic relationship with a phytoplankton called zooxanthellae (zo•o•xan•thel•la). Zooxanthellae are photosynthetic and produce approximately 90 percent of the coral’s essential nutrients. Thanks to the bioluminescent zooxanthellae, coral’s display bright, stunning colors that have made them top tourist spots.

In times when the reef experiences an unusual temperature change, even as little as 1 degree Celsius, that results in warmer waters they expel their zooxanthellae. For most corals it means a loss of a food source, which could lead to their destruction. Though some coral species have been found to survive without their symbiotic; however, most struggle for survival and ultimately die, leaving only the calcium carbonate skeleton behind.
Coral bleaching is a relatively quick process considering it only takes a temperature change of 1 degree, lasting for four weeks to start a bleaching event. In addition, after 8 weeks of temperature change the corals tragically die. Excessive pollution resulting in pH change can also cause these catastrophic mass bleachings. Some experts debate that the bleaching is beneficial for the corals, “Bleaching may not signify coral’s imminent demise, but its ability to tough out new conditions.” Either way corals need our help, but there is hope that they can make a mighty comeback.


Paul Marshall and Heidi Schuttenberg, A Reef Manager’s Guide to Coral Bleaching, Great Barrier Reef Marine Park Authority, November 30, 2006 (p.5)

Hope for the Future

The NOAA stated, “In 2005, the U.S. lost half of its coral reefs in the Caribbean in one year due to massive bleaching events.” When the coral dies so does the reef, as the species that once inhabited it are forced to move locations. In total, coral reef systems support 2 million species globally; the loss of reefs is the loss of much more, as they are an oasis for growth and protection of many marine species. Sustaining reefs is an integral part of keeping our oceans clean and healthy.

The coral triangle has experienced 30% reef loss and the consequences are obvious: No reef, no life. The abundant marine life have scattered after coral deaths. In 1998 the first coral bleaching happened on a global scale, then again in 2005 and 2010. If this pattern of mass coral bleaching continues the oceans will be in trouble, and so will we.

The world’s largest reef, the Great Barrier Reef, is not immune to the threat of coral bleaching; in fact, both in 2005 and 2008 over half of the coral was bleached. Many government agencies such as the NOAA in the U.S. have recognized the need for protecting reefs, so they developed the “NOAA Coral Conservation Program” which monitors reefs and develops solutions for preventing bleaching. The best solution is to more strictly limit the amount of Carbon Dioxide emissions that are released into the atmosphere, which result in warmer ocean temperatures. Simple actions such as lowering your carbon footprint and recycling result in big changes for the environment.

The IUCN red list recently added 20 coral species, which raises awareness about the need to protect corals. Corals, fish, marine mammals, they all need each other to survive and the coral is the ecosystem’s core which destroyed leaves the ocean in pieces. Without healthy coral reefs ecotourism and the fishing industry suffer. Humans depend on the oceans for a stable economy, which is just another reason why it is pertinent that we direct attention to helping corals rebound.





“Climate Change.” NOAA’s Coral Reef Conservation Program:. N.p., n.d. Web. 14 Sept. 2014. <>.
“Dinoflagellata: Life History and Ecology.” Life History and Ecology of the Dinoflagellata. N.p., n.d. Web. 14 Sept. 2014. <>.
“Is Bleaching Coral’s Way of Making the Best of a Bad Situation?.” National Geographic. National Geographic Society, n.d. Web. 14 Sept. 2014. <>.
“Scientists: Caribbean coral die-off may be worst ever, Southeast Asia and Indian Ocean bleaching “may prove to be the worst such event known to science..” ThinkProgress Scientists Caribbean coral dieoff may be worst ever Southeast Asia and Indian Ocean bleaching may prove to be the worst such event known to science Comments. N.p., n.d. Web. 14 Sept. 2014. <>.
Shah, Anup . “Coral Reefs.” Global Issues. N.p., n.d. Web. 13 Sept. 2014. <>.
“What is coral bleaching?.” National Oceanic and Atmospheric Administration. N.p., n.d. Web. 14 Sept. 2014. <>.
“Working together today for a healthier Reef tomorrow….” Great Barrier Reef Marine Park Authority. Australian Government, n.d. Web. 14 Sept. 2014. <>.