Coral Catastrophe

The race to save the Great Barrier Reef before it’s too late.

It may be the ultimate stress test. Climate change brought on by human activity is placing the planet under unprecedented strain. With threats of increased drought, floods, storms, polar melting, unbearably hot temperatures, and more, the question is how well we and the environment will be able to handle it. Early indications are not good.

The Great Barrier Reef off the coast of Australia is the world’s largest living thing. And it is dying right in front of our eyes. In the past year alone, coral bleaching brought on by climate change (also overfishing, pollution, coral mining, and other human activities) has turned most of the reef into the pale skeletal remains of what used to be a colourful, healthy ecosystem teeming with life.

Coral bleaching is a global environmental phenomenon that’s been around for decades. But it’s grown much more severe in recent years. The climate is changing so fast, coral simply can’t adapt. The various species of coral can only live within a narrow range of environmental conditions. In other words, they hate change so much, it can kill them.

Coral relies on a close relationship with single-celled algae called zooxanthellae that live inside the coral cells. These algae use sunlight and produce food that is then transferred to the coral tissues and give coral their colour. The two cannot live without one another. When the environment changes, the algae produce toxic compounds and damage the cellular structure of the coral. Eventually, the algae disappear and the coral dies, resulting in the ghostly white skeleton.

I think if you’re not willing to take risks in scientific research, you’ll end up just doing things that have already been done.

However, there may be a way to help coral deal with the stress. Madeleine van Oppen, a senior research scientist at the Australian Institute of Marine Science, is working on ways to make coral more resilient.

“Algae has a very important impact on the stress tolerance of coral, so depending on which strain or species of algae the coral associates with, it has a very large effect on its relative tolerance to, say, temperature.”

So van Oppen and her team are selectively breeding algae. “If you grow a culture that goes through many cell divisions and you grow them under the conditions, say high temperature, then you hope that some of these random mutations might be beneficial. Some might result in the algae being more able to cope with the high temperature. And if that’s the case, that mutant will out-compete everything else.”

To test it, they can then take the mutant algae and implant it into coral in their National Sea Simulator, a massive aquarium that acts as a living laboratory. Here they can also see what happens when they manipulate the conditions under which coral live. They can even grow new coral and watch what the effect is when they change the temperature of the water, the acidity, or the amount of sediment and nutrients. They can also cross-breed coral in the hopes of growing hybrids that have helpful characteristics, the same way it’s done with crops.

Time is not on their side. Even if all greenhouse gas emissions were stopped, climate change would continue for many years. “It’s quite a grim picture on the future of coral reefs,” says van Oppen. Not only that, she and her team really don’t know whether their experiments will go anywhere. “Sometimes things don’t work and you waste a lot of time, so yeah, the pressure’s always on.” But finding new solutions to save coral reefs is a game of taking risks. There’s no other way. “I think if you’re not willing to take risks in scientific research, you’ll end up just doing things that have already been done.”

Look at the Great Barrier Reef today and one thing is obvious. What’s already been done isn’t helping.


Header: A before-and-after image of the bleaching in American Samoa. The first image was taken in December 2014. The second image was taken in February 2015, when the XL Catlin Seaview Survey responded to a coral bleaching alert from the National Oceanic and Atmospheric Administration.