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The Science Survey

We've got the news down to a science!

The Science Survey

We've got the news down to a science!

The Science Survey

Coral Bleaching : A Call to Action

As our coral reefs continue to die at record rates, our planet — and by extension ourselves — is put more and more at risk.
Some coral species are more endangered than others, with the Acropora, seen above, being listed as threatened. (Photo Credit: Vardhan Patankar, CC BY-SA 4.0 , via Wikimedia Commons)

The fact that our planet is getting warmer has hung in the back of our minds for decades. Even though scientists and activists continue to call for immediate attention, it’s easy to feel like climate change is a problem for future generations, something that will show its true horrors long after it matters to the people living right now. Unfortunately, climate change is here now, and we are the only people who can do anything about it. 

Climate change obviously impacts the temperatures of our planet, but we often forget that that includes our oceans. Changing ocean temperatures can lead to coral bleaching. Coral bleaching is when coral, known for its vibrant colors, turns bone-white in response to changing ocean temperatures. While most documented cases are caused by temperature increases, one incident in the Florida Keys in 2010 proved that temperatures dropping to around 12 degrees Fahrenheit could be just as fatal. 

At a glance, this may not feel like a serious concern. Many appreciate the beauty of coral, but don’t try to understand it beyond that. But coral – and by extension the ocean – is essential to the health of our planet. Our coral reefs are some of the most ecologically diverse places in the world, providing habitats for over one million different species and housing more animals than any other marine habitat. 

From a more human-oriented perspective, reefs provide food, income, and protection for over half a billion people. The food and income is a result of the prosperous fishing possible in thriving coral reefs. Coral protects shorelines from eroding, which keeps people’s houses stable for longer. They also draw in tourists, with countries like Australia and Bermuda being known for their prime snorkeling locations.  

Many scientists are also starting to use coral reef animals and plants as potential treatments or even cures for health conditions like cancer, arthritis, or viruses. In fact, over half of all cancer treatment research is focused on chemical compounds produced by organisms living in coral reefs.  

The list of how coral reefs are intertwined with maintaining the health of our planet goes on, even tying into climate change as corals absorb carbon dioxide fifty times more efficiently than trees. Protecting coral is in our best interest; our health cannot be separated from coral’s health. 

The declining health of our coral reefs is due to rising ocean temperatures. The easy assumption is that rising ocean temperatures follow the increase in air temperatures, but it’s actually more complicated than that. As our greenhouse gas emissions increase, and trap heat against the Earth’s surface, the majority of that heat is stored in our oceans because water has a higher specific heat capacity than air, meaning it takes more heat for water to increase in temperature than for air. This has led to ocean temperatures breaking new levels almost daily in recent years. 

Throughout late 2023 and early 2024, our planet experienced ‘El Niño,’ which occurs when southeast trade winds weaken. The name is derived from the Spanish word for “little boy,” and referred to Jesus due to the fact that El Niño events seemed to happen near Christmas. This prevents the water upwelling zones, or spots in our oceans that have very cold water, from being distributed, causing areas like Peru to experience severe flooding. El Niño also tends to make our planet warmer, thus expediting the impacts of climate change. 

Scientists have proven that once ocean temperatures increase by two degrees Celsius, the majority of marine wildlife will die.  

Our rising ocean temperature actually doesn’t affect the coral directly. Instead, it impacts the algae living inside of coral, known as zooxanthellae. 

Coral and zooxanthellae have a symbiotic relationship: the coral provides a habitat for the zooxanthellae and the zooxanthellae provide necessary nutrients for the coral. Once the ocean temperatures get too hot, the algae gets stressed and immediately leave the coral, stripping it of its bright color and effectively “bleaching” it. Without the algae, the coral cannot survive for long, and if the water doesn’t cool down sufficiently, the coral will die.  

During my interview with Ms. Lillian Nichols, an A.P Environmental Science teacher at Bronx Science, she elaborated on this idea, stating, “When ocean temperatures spike, coral undergo a stress response that involves them expelling the beneficial photosynthetic algae (zooxanthellae) living within their tissues. Without this algae, the coral is left colorless (“bleached”) in appearance, largely unable to obtain nutrients, and vulnerable to death.  To a lesser extent, bleaching can also be caused by certain pollutants and ocean acidification.” 

Over 50 percent of the Earth’s coral has died in the past thirty years, and the rate of coral death is only expected to increase. There have been four global coral bleaching events throughout our history, and dozens of more localized ones. The first global bleaching event lasted from September 1998 to March 1999, coinciding with El Niño. The second event lasted throughout 2010, and the third, which up until now is the longest-lasting bleaching event ever recorded, spanned from 2014 to 2017. In April 2024, the National Oceanic and Atmospheric Administration, or NOAA, confirmed that we are experiencing the fourth such event. It is clear that these events continue to occur with more intensity and frequency, as every year breaks the heat record set by the year before it. 

Starting as far back as February 2023, scientists have documented mass bleaching throughout the Northern and Southern Hemispheres, ranging from Florida to Brazil to the Great Barrier Reef. The 2023 heatwave in Florida was more severe than anyone predicted, marking the most intense such event in that region ever recorded. This inspired a mad rush to maintain the threatened species in the Florida Keys, with scientists collecting samples of various individual corals, and then loaded into trailers so they could be used as gene banks in the future.  

The worst thing we can do now is give in to the seeming hopelessness of our situation. On the contrary, there are a lot of ways that we can save our planet from total coral death. NOAA has implemented the Iconic Reefs program, which involves transporting coral reefs to cooler water in order to keep them alive, as well as placing sunshades over coral reefs to limit the heat penetrating the water. 

Another such solution is coral seeding, or the process of collecting wild coral sperm and eggs and bringing them back to the lab. This is done especially during the mass coral spawning event, which takes place over a few days once a year and involves the production of hundreds of billions of coral sperm and eggs. Once these are gathered, scientists are able to facilitate the fertilization of said eggs, and over the next ten days, the eggs will go through the larval stage, and eventually into polyps, or coral babies. 

These corals are then brought back to their environment, which is usually the Great Barrier Reef as that is the main location for coral seeding at the moment. The corals are set up with a device to protect the coral in the hopes that they make it to at least one year of age. 

Currently, there are several protective device prototypes being developed, some that look like cages, others like pyramids, even others like small octopuses. But regardless of the effectiveness of any of these devices, they are not a fix-all solution. They merely treat the symptoms, not the sickness. 

Individuals can help, but not in the way that we have been taught to. We cannot reduce, reuse, recycle our way out of coral bleaching or climate change. As Ms. Nichols said, “Human activity impacts the oceans in a host a negative ways, but when it comes to bleaching, it is primarily our society’s continued dependence on fossil fuels to blame. These carbon emissions are what’s driving global warming. Individuals don’t have a lot of control over the source of their energy.”

The fact of the matter is that major industries are contributing to the bulk of carbon emissions, and the form of energy that corporations and even individual houses use is under the power of the government. So if  you want to address the root of the issue, help by using your voice in the government. This includes voting for politicians advocating for environment-oriented legislation, such as mandating that a certain percentage of our energy be provided by wind, solar, hydroelectric, and nuclear power, instead of fossil fuel combustion. It also includes engaging in peaceful protests, such as Climate Marches, to make sure we are not ignored. The idea of our country passing such sweeping legislation may seem impossible, but we’ve done it in the past with legislation such as the Montreal Protocol in 1987. 

Giving up hope in our planet is the easy route. Continuing to believe that we can keep our coral – and by extension ourselves – healthy takes strength, and that is what we will need to save our planet together.

As Ms. Lillian Nichols, an A.P Environmental Science teacher at Bronx Science, said, “Human activity impacts the oceans in a host a negative ways, but when it comes to bleaching, it is primarily our society’s continued dependence on fossil fuels to blame. These carbon emissions are what’s driving global warming. Individuals don’t have a lot of control over the source of their energy.

About the Contributor
Monica Reilly, Staff Reporter
Monica Reilly is an Editor-in-Chief for ‘The Science Survey.' She has always loved using the art of journalism to educate and connect with people. She prioritizes the voices that are often unheard in our world. She loves writing on topics about which she is passionate, as well as on issues that impact people throughout the world. She believes that good journalism and good journalistic photography can make you view the world through someone else’s eyes. Outside of writing articles, she enjoys reading, dancing, and listening to music. In college, Monica hopes to pursue a career in the liberal arts as well as to continue to engage with music and journalism on the side.