Coral Bleaching: Killing the Seas
The estimated environmental and economic value of coral reefs is estimated at $375 billion per year, and over 25% of all marine life depends on coral reefs. Yet, we have lost over 50% of the world’s corals in the last 50 years due to human-induced environmental changes such as ocean acidification and climate change. In 2016 alone, over 29% of the majestic Great Barrier Reef was lost and this past year an equally devastating bleaching event occurred. This is especially alarming when over half a billion people directly rely on healthy coral reefs for food and livelihood, and when coral reefs provide critical habitat for fisheries, create tourism opportunities, and act as natural buffers from large waves that cause coastal erosion. Furthermore, organisms that live on coral reefs are also major sources of new drugs – such as treatments for cancer, arthritis, asthma, AIDS, and other diseases. For example, the cone snail provides serious pain relief by presenting an alternative to opioid drugs from a compound found in the snail’s venom called Rg1A that effectively blocks a key pain pathway receptor in the body.
Upon recognizing all of the benefits that coral reefs provide the environment as well as our society, it is vital that we protect this habitat and make steps to reduce our impact on the climate and the oceans. However, before we can discuss properly discuss these measures, it is important to appreciate coral and understand how we are killing it first.
Corals are not plants, but actually very complex animals with many polyps used for catching food and reproduction. There’s an organism called Zooxanthellae that lives inside the tissues of coral. Zooxanthellae is a dinoflagellate that provides coral with 90% of its food, as well as its coloration. These dinoflagellates (as well as the coral they reside in) need very specific conditions to survive. If their environment becomes too hot or acidic, they produce toxins instead of food and the coral ejects them out. When coral lose Zooxanthellae, all that is left is their transparent tissue and the bright white skeleton underneath. This is why it is called coral bleaching. Once this process occurs, coral are very unlikely to survive.
Climate change exacerbates bleaching. Carbon dioxide released from burning fossil fuels is the biggest cause of atmospheric warming, and the levels of this gas currently exceed the highest previously recorded numbers dating back millions of years. Additionally, over 93% of the atmosphere’s heat is absorbed by the ocean. Both of these factors increase the chances of Zooxanthellae leaving the coral. Furthermore, ocean acidification caused by carbon dioxide absorption into the ocean is another critical stresser resulting in bleaching. You can read more about acidification specifically here.
What are some things you can do to stop coral bleaching? You can help accelerate the transition to clean energy by using your voice to call, email, or tweet to your city or state leaders to let them know this issue – and clean energy – matters to you and others. You can join a local campaign promoting clean energy, such as 350.org, Sierra Club, or The Nature Conservancy, or start your own campaign. You can spread the word about this issue and educate others about why this matters and why it is important. You can take daily steps to reduce your carbon footprint, such as turning off lights, carpooling, and unplugging electronics when they are not in use. Finally, you can support coral preservation efforts already in motion. You can stand behind the Great Barrier Reef by joining the call for a ban on new coal plants or supporting organizations that actively aim to make a difference.
Coral reefs are incredible structures that host beautiful ecosystems many people across the world flock to see. They provide many benefits to our health through medicine, to our economy, to our fishing industries, and to the health of our cities by acting as buffers from hazardous waves. Let’s not let this amazing organism and natural beauty be lost. It’s time to rise up and start protecting coral.