“CORAL REEFS REPRESENT SOME OF THE
WORLD’S MOST SPECTACULAR BEAUTY SPOTS,
BUT THEY ARE THE FOUNDATION OF MARINE LIFE:
WITHOUT THEM, MANY OF THE SEA’S MOST
EXQUISITE SPECIES WILL NOT SURVIVE”
- Sheherazade Goldsmith
Coral reefs, the underground rainforests, have various vibrant colours and give life to entire ecosystems underwater. But, due to the changes in the environment, these organisms are under attack and are dying.
Coral Reefs and Their Colour
Coral reefs get their unique colours from microscopic algae called Zooxanthellae, which have a symbiotic relationship where the algae produce food through photosynthesis and give that to the coral and the coral polyps, in turn, provide a home to the algae. Coral polyps are in actuality clear and so they get their colour from the algae that reside in them.
Why is the Colour Relevant?
Only the outer layer of a coral reef is alive, underneath the living surface is a calcium carbonate skeleton that can vary in age. Coral polyps are sensitive to changes in temperature of the water they live in, and so, the ocean starts to get warmer through various climate change variables. One such variable being the frequency of El Niño events; once that happens the coral polyps expel the algae causing the coral reef to bleach. The white coral translates to algae being driven and once this happens it is rare for a coral to be revived.
Causes of Coral Bleaching :
Climate Change
- Climate change (the overall change of the climate in the atmosphere) has caused the temperature of the water to warm and this has a bad effect on the coral reefs as they are sensitive to temperature changes in the water. Climate change has caused Glaciers to melt due to the temperature rise which scientists say has made the water’s pH levels change to being more acidic. This greatly affects the coral reefs as the skeleton of the coral has difficulty forming underwater that has become more acidic than the norm. The density of the coral’s skeleton will decrease according to a study Proceeding of National Academy of Sciences leaving the coral more vulnerable to breakage.
El Niño (natural but due to global warming, patterns are irregular and may have a greater impact than they would have without global warming)
- Warming from El Niño is relatively short and is temporary though due to climate change, its effects have become worse. In a study, conducted by Claar, Danielle C., Lisa Szostek, Jamie M. Mcdevitt-Irwin, Julian J. Schanze, and Julia K. Baum (2018), research is done to show global warming effects on El Niño and how it affects coral reefs. El Niño is known to raise the temperature of the surface water of oceans and seas, but with the long-term effects of climate change/global warming, coral reefs are not able to adapt. The study concluded that the effects of the heat stress caused by climate change and the added effects of El Niño and La Niña have caused coral bleaching to be more prominent and coral reefs are not able to adapt to both climate change and El Niño/La Niña weather patterns. The study also points that the decline is more serious in the equatorial area than it is in areas of higher latitude. This study also suggested that more studies should be conducted and measures are put in place in order to minimize the damage on coral reefs.
Overfishing
- Overfishing causes changes in ecosystems which for coral reefs is very hard to adapt to. Due to poor management of fisheries, coral reefs can die because of the depletion of fishes and damage from fishing equipment.
Pollution
- This ties back with overfishing as many fishermen use large nets to capture fish and sometimes, these nets get left in the ocean which then snag onto coral reefs causing significant damage and blocking fishes from resources/protection gained from the coral reef. These nets may also be blocking nutrients that could be gained from the sunlight. Plastics are also affecting coral reefs because as clusters of plastics float on the surface of the water, it blocks the sunlight as well. Pollution also comes in the form of fertilizers, oil spills, and chemical waste that makes its way into the waters in which coral reefs reside. Products we use when we go swimming, like sunscreen, also have the ability to cause harm to reefs. The NOAA (National Oceanic Atmospheric Administration) created an infographic in which they list the ingredients found in sunscreens that should be avoided. They dubbed chemicals such as Oxybenzone, Benzophenone-1, and more considered dangerous for the ocean. This has led countries like Mexico to ban all products containing the listed ingredients.
The Impact of Coral Bleaching
Many marine species are dependent on coral reefs, an estimated 25%, this includes over 4,000 species of fish. Humans around the world are also dependent on coral reefs as they provide food; as food chains show humans need fish and fish need coral reefs. Coral reefs also provide coastal protection as they form a barrier to harsh waves, floods, and storms. Due to their barrier-like qualities, they protect coasts from erosion, they also have great economic worth as they bring in tourism due to their beautiful colours. Losing coral reefs would mean extinction for some species of fish and also a shortage of food for people and job loss for fishermen.
Although many people live in urban areas and do not see the significance of coral reefs in the broader picture of climate change, attention must be focused on protecting what we have now. Many focus on CO2 or lowering GHG emissions, few will remember coral reefs are victims of climate change. We as consumers must be more aware of the significance of coral reefs in our lives.
References:
“Basic Information about Coral Reefs.” EPA. May 04, 2018. https://www.epa.gov/coral-reefs/basic-information-about-coral-reefs#:~:text=Because photosynthesis requires sunlight, most, inside the polyps show through.
“How Does Overfishing Threaten Coral Reefs?” NOAA’s National Ocean Service. June 23, 2016. https://oceanservice.noaa.gov/facts/coral-overfishing.html.
Cho, Renee. “El Niño and Global Warming-What’s the Connection?” State of the Planet. February 20, 2019. https://news.climate.columbia.edu/2016/02/02/el-nino-and-global-warming-whats-the-connection/.
Claar, Danielle C., Lisa Szostek, Jamie M. Mcdevitt-Irwin, Julian J. Schanze, and Julia K. Baum. “Global Patterns and Impacts of El Niño Events on Coral Reefs: A Meta-analysis.” Plos One 13, no. 2 (February 05, 2018). doi:10.1371/journal.pone.0190957.
Hancock, Lorin. “Everything You Need to Know About Coral Bleaching-And How We Can Stop It.” WWF. Accessed May 26, 2021. https://www.worldwildlife.org/pages/everything-you-need-to-know-about-coral-bleaching-and-how-we-can-stop-it.
Lindsey, Rebecca, and LuAnn Dahlman. “Climate Change: Global Temperature: NOAA Climate.gov.” Climate.gov. March 15, 2021. https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature#:~:text=Change over time&text=According to NOAA’s 2020 Annual, more than twice that rate.
NOAA. “Skincare Chemicals and Marine Life.” National Ocean Service website. https://oceanservice.noaa.gov/news/sunscreen-corals.html, 02/26/21.
Petersen, Ben. “Hot Flashes in the Ocean.” Climate Change: How El Niño Affects Coral Reefs | Ask A Biologist. May 14, 2018. Accessed May 26, 2021. https://askabiologist.asu.edu/plosable/el-nino-coral-reefs.
Seemann, Katie. “These 7 Locations Have Sunscreen Bans — — Here’s What You Need To Know.” Zen Life and Travel. February 07, 2021. https://www.zenlifeandtravel.com/sunscreen-bans/.
