AMU Emergency Management Public Safety

Coral Bleaching: What is it and Why Does it Matter?

Coral reefs are vital to ocean health

Coral reefs are living, breathing, ecosystems in the ocean that are vital to its health and balance. Referred to as the rainforests of the sea, coral reefs offer a unique and diverse ecosystem that provides food and shelter for an estimated 25 percent of all fish, crustaceans, and other sea life. Humans also [link url=”http://ocean.si.edu/corals-and-coral-reefs#section_Coral_Bleaching” title=”benefit from coral reefs,“] as they provide food, medicine, shoreline protection, and tourism jobs — all of which add to the national economy.

Coral reefs have an estimated value of $30 billion, with some numbers claiming close to $172 billion for the resources and products they provide. Their loss would have a significant impact to the national and global economy, and any disruption to these reefs is likely to alter ocean functions and negatively impact many other species, including fish, mammals, birds, and humans.

Understanding coral reefs

Coral reefs exist throughout the ocean, in both deep and shallow waters. However, reef-building corals are only found in the shallower and warmer waters of the subtropical and tropical oceans. An algae known as zooxanthellae provides a critical function to the growth and production of a reef system – it provides food to its coral hosts. These algae, which live inside the corals, are tiny and colorful, rely on the sunlight for energy, and can only tolerate small changes in water temperatures.

Corals take a [link url=”http://ocean.si.edu/corals-and-coral-reefs#section_Coral_Bleaching” title=”long time to grow“] — approximately one inch or less per year. The fastest growing corals gaining about six inches per year. Reefs can last for a very long time; the [link url=”http://www.cnn.com/2016/04/20/asia/great-barrier-reef-coral-bleaching/” title=”Great Barrier Reef“] is one example of a reef that has been in existence for nearly [link url=”http://ocean.si.edu/corals-and-coral-reefs#section_Coral_Bleaching” title=”20,000 years“]. Much like trees, corals produce growth rings, allowing scientists to develop a timeline for the reef’s existence.

Human influences negatively impact coral reefs

Coral reefs across the globe are in trouble thanks to anthropogenic (human) influences on climate change. Rising global temperatures are warming ocean waters and exceeding the acceptable temperatures for these algae. Compounding the problem is ocean acidification – a process that is caused by the ocean’s capture of carbon from the atmosphere. These two processes have different impacts on coral reefs, but both contribute to a reef’s destruction. Acidification makes it difficult for coral to build their skeletons, while warming temperatures kill the algae that provide them with food.

Coral bleaching

The [link url=”http://www.coralcoe.org.au/resources/for-managers/coral-bleaching-and-the-great-barrier-reef” title=”loss of the zooxanthellae algae“] removes the coral’s food and color source, exposing a coral’s skeleton, making them transparent, or white. Not all corals that undergo bleaching die, but the longer the adverse conditions exist, the higher the chances the coral and the reef will die – either from disease or starvation.

coral infographic
Photo Credit: NOAA

There are [link url=”http://www.cbc.ca/news/technology/coral-heat-pollution-bacteria-disease-1.3620305″ title=”other causes of coral bleaching“], such as water run-off from land, including mud and soil that is contaminated with fertilizers, pesticides, and other toxic chemicals, overfishing, and the over harvesting of corals. The impact of all the threats combined greatly increases the risks to coral reefs. However, the greatest threats to these vital ecosystems come from greenhouse gas emissions that increase atmospheric carbon levels, that then contribute to warming water temperatures and ocean acidification.

Ocean protection critical for life

Oceans are vital to human life and the assets, goods, and services (transportation, recreation, food, etc.) of the [link url=”http://www.worldwildlife.org/stories/ocean-assets-valued-at-24-trillion-but-dwindling-fast” title=”world’s oceans are valued at nearly $24 trillion“]. Since the oceans also provide about 50 percent of the oxygen we need to live, and capture roughly 30 percent of atmospheric carbon, protecting them is critical to human survival.

Decreasing the amount of chemicals in runoff, preventing overfishing, and reducing water pollution will help coral reefs survive. But the best way to protect them and ensure they thrive is by reducing carbon emissions globally.

Kimberly Arsenault serves as an intern at the Cleveland/Bradley County Emergency Management Agency where she works on plan revisions and special projects. Previously, Kimberly spent 15 years in commercial and business aviation. Her positions included station manager at the former Midwest Express Airlines, as well as corporate flight attendant, inflight manager, and charter flight coordinator. Kimberly currently holds a master's degree in emergency and disaster management from American Public University.

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