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Coral or Chaos? 

Which Do We Want? Data from the Great Barrier Reef suggests we’ve already chosen the latter.

Diving in the Reef

by Ari Tulk, 2023

The Great Barrier Reef is a beautiful and complex coral ecosystem off the northeastern coast of Australia.

It has existed–and thrived–for 1.05 million years. Reef ecosystems are some of the oldest, largest, and most diverse of the world. Or so they were. 


Reefs contain a quarter of the world’s marine life and are like the thick walls of a fortress, protecting coastlines from storms, purifying the air and water, and guarding against erosion of coastal lands. 


Apart from how much we (the whole of Australia’s people, plants, and animals, and the entirety of the world) need the Great Barrier Reef to survive physically, the disappearance of its beauty would break our hearts as much as our economy, and our earth–perhaps even more. 


As an Australian immigrant to the U.S., the Great Barrier Reef has a special significance to me. Being made to feel like an outsider in the United States, the place that I’ve grown up in, the place I call home, sometimes makes me feel ashamed of where I come from, but the Great Barrier Reef has always symbolized why I should be proud of being Australian. 


When daily reminders of my difference make me feel like an outsider in the United States–the place I’ve grown up in, the place I call home–I sometimes resent and feel ashamed of where I come from. But the Great Barrier Reef, a symbol to me of all the wonderful things about the country, is a reminder to be proud of being Australian. 


It would break my heart if, by the time I get to visit Australia for the first time since I was baby, it is too late to see the Great Barrier Reef in its full glory.


The brightly-colored coral, the thousands of species living there, the sparkling aqua marine water, are together so breathtaking that any viewer is struck by its power and delicacy.  For the Great Barrier Reef is an image for us all to see, of the glorious harmony of a balanced ecosystem.

But this most vital and beloved ecosystem is dying.


How?? How can an ancient ecosystem die after hundreds of thousands of years of harmonious life and balance? The answer is easily. It is too easy to set the scale rocking. We can kill an ecosystem at the drop of a hat–that’s why we have to hold onto the hat, and polish it daily, and wear it proudly–because ecosystems are just that perfect.


Each organism in an ecosystem is utterly dependent on everyone else, and none more so than those of the Great Barrier Reef. Because of the delicate balance of food chains and food webs–the means of transference of energy in all ecosystems–if one part is taken away, or added, everything else is knocked out of balance. 


Ocean acidification and global warming, both caused by an excess of carbon in the atmosphere, are doing just that–messing up ecosystems all over the world. Oceans are the most sensitive–they are the raw nerve to everything going wrong, so we can see the horrible effects of climate change first in our ocean, and especially in the reefs.


What makes the Great Barrier Reef so fragile and strong at the same time?


The answer is in the complexity of the interwoven food chains within the ecosystem.


Ecosystems are complex food webs, made up of many food chains. Food chains are single pathways of feeding relationships and energy transfers between organisms. Food webs are all the food chains connected. Food webs can be very complex, containing thousands of species–it depends on the size of the ecosystem and the level of biodiversity.  


Zooming in on a single fragment of the immense coral reef ecosystem, we can begin to see how complex this large ecosystem is–in just 17 species there are so many interconnected feeding relationships!


In The Great Barrier Reef the energy begins in the marine algae, which creates energy from the sunlight. The marine algae is eaten by the krill, plankton, giant clams and mollusks, which are then eaten by the  the clown fish, the box jellyfish, the hump-backed whale, the whale shark, and the red base, who are then eaten by the sea turtles, sea snakes, tiger sharks, sea eagles, dugongs and whale sharks, who are then eaten by the dugongs, white-tipped reef sharks, hump-backed whales, tiger sharks, and whale sharks who are eaten by no one, being apex predators.

Considering the immense complexity of the Great Barrier Reef, you may be confused as to how it can be so delicate.


The resilience of the ecosystem depends entirely on biodiversity.


Biodiversity refers to the different kinds of species in specific habitats. The more species in an ecosystem the better it is at dealing with challenges. 


Threats to biodiversity–such as diseases, global warming, isolation due to habitat fragmentation, homogenization (ecosystems in similar climates becoming the same due to species introduction), species exploitation (such as mass farming), pollution, and climate change–are threats to ecosystems. 

Anything that harms any part of any ecosystem threatens biodiversity.

The Great Barrier Reef, however biodiverse it is, cannot recover easily from the loss of coral. It was able to continue surviving when the parrotfish was exploited for human trade, but the coral isn’t just a dependent species, it’s the heart of the reef. It is depended on for shelter, food, territory, hunting, and hundreds of other things.

Coral is dying, attacked by both global warming and ocean acidification—twin evils caused by excess carbon.


Carbon Brief The first diagram, of the Great Barrier Reef,  shows coral loss, and coral gain, green meaning where coral has recovered better, and red showing where it has completely died. The second graph shows heat exposure. The red shows high heat, and the blue low heat. If one compares these diagrams, one will see that the places that are blue in the second graph, recovered better, and the places that were exposed to high heat were lost completely.





Ocean acidification is the dramatic pH increase in our oceans. The ocean absorbs 50% of our carbon emissions. When carbon dioxide and water combine in a solution, they split apart to become hydrogen ions. Hydrogen ions eat carbonate, which Coral uses to develop its skeleton, and to outgrow the constant erosion that the ever-changing tides wreak on them. The introduction of a competitor in colossal numbers deprives the coral from the food it needs. As the corals cannot fully regenerate what has been lost to erosion, they are gradually dissolving, increasing susceptibility to any challenges they might face.


NOAA View Global Data Explorer This is a representation of the pH of Australia’s coastal oceans in 1861. Compare it to the key below to see that in 1861 the pH was 8.3.

NOAA View Global Data Explorer This is a representation of the pH of Australia’s coastal oceans in 2022. Compare it to the key below it to see that the pH is now 8.



NOAA View Global Data Explorer This is a representation of a scientific prediction of what the pH of Australia’s coastal oceans will be in 2100. Compare the color of the oceans to the colors in the key below it to see that the pH will then be only 7.7.



The most dangerous challenge they are facing is global warming.


Humans have disrupted the delicate balance of the carbon cycle (how the earth naturally releases and absorbs carbon, maintaining balanced circulation) by putting out carbon into the atmosphere, faster than any other natural carbon release. We create it, but not absorb it. In the last 150 years there has been a 42% increase in carbon in the atmosphere. This gas has the ability to hold heat. When the warmth from the sun enters the atmosphere, carbon dioxide traps it, weaving a thick insulating blanket around the earth.  


The average temperatures are increasing, and the oceans are heating up. Unfortunately, coral is very sensitive to heat. Like a human temperature, only a few degrees above the normal can be fatal. Corals collaborate to create energy with zooxanthellae, small photosynthesizing plant cells living inside of them. When temperatures rise, corals expel the algal cells that live inside them, leaving them translucently white and deprived of an essential food source. 


As ocean temperatures rise exceedingly fast, devastating bleaching events are becoming more regular, with less time between each one than the one before. Major bleaching events have occurred in 1998, 2002, 2006, 2016 and 2017.


Australia’s most precious and vital ecosystem is suffering, but I believe that its delicacy, though it enables swift degradation, is not a weakness. It gives me hope for swift regeneration! This fragility gives me hope for our beautiful, wronged earth. This proof of our earth’s ecosystemic connection shows that our reefs are not lost. I believe that if we change something even small, the whole ecosystem will feel it, and begin the long process of healing immediately. 

Because if we can unravel an ecosystem, just by threatening one species, couldn’t we step onto the right path, the path of earth-nurturing, and respect for each other and our planet–couldn’t we heal an ecosystem, just by bringing one back?

Coral Reef Island
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Vex This shows the percentages of coral loss in different areas of the Great Barrier Reef. The further south the cooler the temperatures, and also the further south the better the coral recovery. The further north, the hotter the temperatures, because it is closer to the equator, and also the further north, the more coral has died.

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