We haven’t yet discussed bleaching of our coral reefs which we will address in greater detail next month. But for now, we want to highlight coral reef bleaching as one example of the economic costs of climate change, which we also will address in greater detail. We believe people should begin learning about and considering the costs of carbon emissions which have accelerated rising water temperatures in our oceans. Economic consequences from global warming are not limited to extreme weather and powerful storms. There are many different adverse impacts upon humans because of carbon emissions.
First, what exactly is coral bleaching? The simplest explanation is when corals lose their color and turn white, which indicates corals are, or may be unhealthy. A more biological explanation begins with knowing why corals are bright and colorful. It is because “microscopic algae called zooxanthellae” live inside the coral and this creates a “symbiotic” relationship which is mutually beneficial to the coral and algae, and each helps the other to survive. “Algae belonging to the group known as dinoflagellates live inside the corals’ tissues and “use photosynthesis to produce nutrients, many of which they pass to the corals’ cells. The corals in turn emit waste products in the form of ammonium, which the algae consume as a nutrient.” Symbiosis also helps build the coral reefs because healthy corals hosting algae can deposit calcium carbonate which is the hard skeleton that forms the beautiful coral reefs we see in underwater photographs. Symbiotic corals can deposit calcium carbonate “up to 10 times faster than non-symbiotic corals.”
The bleaching problems for corals are caused by environmental changes in our oceans. Perhaps the most significant problem for coral is the changing water temperature where the waters are getting warmer. If the water gets too hot, which may only be a few degrees, it stresses out the coral and the coral expels the algae. This destroys that great symbiosis because as the algae leaves the coral, it takes away the important source of nutrients from the coral, and the coral fades until it looks like it has been bleached. At this point the coral is not dead but is vulnerable to diseases, and likely to die. “If the temperature stays high, the coral won’t let the algae back inside, and the coral will die.” Coral may bleach for other reasons including “extremely low tides, pollution, or too much sunlight.” Today, reefs in the Atlantic, Pacific, and Indian Oceans are all experiencing bleaching, and many of these reefs are seriously threatened. To get a better picture of this threat, “[s]ince early 2023, mass bleaching of coral reefs has been confirmed throughout the tropics, including in Florida in the U.S.; the Caribbean; Brazil; the eastern Tropical Pacific (including Mexico, El Salvador, Costa Rica, Panama and Colombia); Australia’s Great Barrier Reef; large areas of the South Pacific (including Fiji, Vanuatu, Tuvalu, Kiribati, the Samoas and French Polynesia); the Red Sea (including the Gulf of Aqaba); the Persian Gulf; and the Gulf of Aden.” That is a huge amount of coral bleaching!
So, why does coral bleaching really matter? Once the corals die, they rarely come back. With fewer corals surviving, the corals have a much harder time reproducing. If the corals cannot reproduce, the coral reef will continue deteriorating. “According to the National Oceanic and Atmospheric Association, between 2014 and 2017 almost 75% of the world’s tropical coral reefs experienced heat-stress severe enough to trigger bleaching. For 30% of the world’s reefs, that heat-stress was enough to kill coral.” Coral reefs are the building blocks for entire reef ecosystems. We wrote an article on ecosystems which may be useful for you to read to refresh your understanding about the interplay among different species composing an ecosystem. Deteriorating corals will adversely impact reef ecosystems upon which people and wildlife depend. “Coral reefs support some of the most biodiverse ecosystems on the planet. Thousands of marine animals depend on coral reefs for survival, including some species of sea turtles, fish, crabs, shrimp, jellyfish, sea birds, starfish, and more. Coral reefs provide shelter, spawning grounds, and protection from predators. They also support organisms at the base of ocean food chains. As reef ecosystems collapse, already at-risk species may face extinction.”
How does this affect humans? Bleached coral “impacts peoples’ livelihoods, food security, and safety.” Think about the chain reaction to a dead or dying coral reef and the impacts upon the food chain. Without healthy coral, the smallest organisms up through the largest fish will disappear. “Bleached coral also compounds the overfishing crisis by removing links in the food web and depriving some fish and crustacean species of a place to spawn and develop. Anyone relying on these reef inhabitants as a primary source of income or protein will be in trouble. Reef tourism brings in billions of dollars each year and supports thousands of jobs. Bleached coral reefs, devoid of magnificent marine species, jeopardize it all.” Fishing, diving, and sightseeing will be severely hurt and all the people in the businesses relying on the reefs will be impacted, including hotels, restaurants, gift shops, stores, etc. Another huge loss for humans is the protection of nature. Healthy reefs are natural barriers keeping our coasts safer as they absorb the force of the waves and storm surges from powerful storms which can cause devastating property losses.
Nobody wants to see our magnificent reefs die. Coral reefs are treasures. If we want to have our children and grandchildren enjoy the wonders of our coral reef ecosystems, WE MUST DO SOMETHING ABOUT IT, otherwise they will be gone. It takes a village, and we need tons of people joining the worldwide grassroot campaigns to protect our environment, which includes putting pressure on our governments and leaders to make those changes. Right now, world governments are standing in the way of environmental protection and are NOT doing enough to help save our planet. Think about it. Help make that change.
Sources:
© Jürgen Freund / WWF
https://www.worldwildlife.org/pages/everything-you-need-to-know-about-coral- bleaching-and-how-we-can-stop-it
https://time.com/6969434/the-big-climate-costs-that-lie-just-below-the-surface/
https://www.noaa.gov/news-release/noaa-confirms-4th-global-coral-bleaching-event
https://www.princeton.edu/news/2016/11/02/when-corals-met-algae-symbiotic-relationship-crucial-reef-survival-dates-triassic
