Is the Great Barrier Reef dead?
A writer named Rowan Jacobsen recently wrote and posted an obituary for the Great Barrier Reef on a website known as Outside Online. Most experts agree that the Great Barrier Reef is not dead, but it is facing damage and there is great cause for concern. Here is an excerpt from Jacobsen's Great Barrier Reef obituary:
"The Great Barrier Reef of Australia passed away in 2016 after a long illness. It was 25 million years old.
For most of its life, the reef was the world’s largest living structure, and the only one visible from space. It was 1,400 miles long, with 2,900 individual reefs and 1,050 islands. In total area, it was larger than the United Kingdom, and it contained more biodiversity than all of Europe combined. It harbored 1,625 species of fish, 3,000 species of mollusk, 450 species of coral, 220 species of birds, and 30 species of whales and dolphins. Among its many other achievements, the reef was home to one of the world’s largest populations of dugong and the largest breeding ground of green turtles."
Jacobsen listed the cause of death of the Great Barrier Reef as coral bleaching. Here is the quote:
"In 1981, the same year that UNESCO designated the reef a World Heritage Site and called it “the most impressive marine area in the world,” it experienced its first mass-bleaching incident. Corals derive their astonishing colors, and much of their nourishment, from symbiotic algae that live on their surfaces. The algae photosynthesize and make sugars, which the corals feed on. But when temperatures rise too high, the algae produce too much oxygen, which is toxic in high concentrations, and the corals must eject their algae to survive. Without the algae, the corals turn bone white and begin to starve. If water temperatures soon return to normal, the corals can recruit new algae and recover, but if not, they will die in months. In 1981, water temperatures soared, two-thirds of the coral in the inner portions of the reef bleached, and scientists began to suspect that climate change threatened coral reefs in ways that no marine park could prevent.
By the turn of the millennium, mass bleachings were common. The winter of 1997–98 brought the next big one, followed by an even more severe one in 2001–02, and another whopper in 2005–06. By then, it was apparent that warming water was not the only threat brought by climate change. As the oceans absorbed more carbon from the atmosphere, they became more acidic, and that acid was beginning to dissolve the living reef itself."
Deborah Netburn reported in the Los Angeles Times that the Great Barrier Reef is not dead, but it is in trouble. She cites Kim Cobb, who is a professor at Georgia Technical University's School of Earth and Atmospheric Sciences. Cobb studies coral resilience. She concedes that recently there was a massive bleaching event. She explains the process that occurs during a bleaching event below:
"Coral is an animal, and the animal exists in symbiosis with photosynthetic algae. The algae provides food for the coral in exchange for a great home. But when the water gets too warm, the algae become chemically destructive to the coral.
When that happens, the coral convulses and spits out puffs of algae to protect itself. That removes all the color from the coral tissue which is transparent, allowing you to see right through to the underlying skeleton. So you are not necessarily seeing dead coral, you’re really just seeing clear coral without its algae."
Symbiosis is a mutually beneficial relationship between two organisms, where each member is interdependent. An example would be oxpeckers, a type of bird that rides around on zebras. The oxpecker gets a meal from this relationship, picking lice and other parasites off the zebra. The zebra gets a free security system, due to the scream an oxpecker emits when a predator is near.
Cobb says that the rise in ocean temperature lasted nine months in 2015 due to an extended El Nino event. Oceanographers are also worried about the general warming trend in ocean waters.
Many scientists are concerned that Jacobsen's obituary could lead people to believe that there is no hope for the Great Barrier Reef. Many experts see this as a cause for intervention and study, not for panic.
"Professor John Pandolfi from the ARC Centre at the University of Queensland has expressed hope. 'It is critically important now to bolster the resilience of the reef, and to maximize its natural capacity to recover.' But the effects are serious and possibly permanent. 'The reef is no longer as resilient as it once was, and it's struggling to cope with three bleaching events in just 18 years,' he said."