Coral Bleaching

It’s happening, and it’s worse than a bleached…You know. But what exactly is it? What causes it? And why should we care?

Coral and algae live a harmonious life together, like butter and bread. But when exposed to pollutants or extended periods of warmer (or cooler) ocean temperatures, the relationship can become toxic. More specifically, the algae produces toxic compounds and instead of sticking through the bumpy times, the coral sends the algae packing. With no algae to cover itself with, the coral is effectively naked. The translucent coral tissue lets us see right to the bones, giving the bleached effect we refer to. This bleaching can leave the coral without its major food source and more susceptible to disease. Like a misunderstood kiss in a rom-com, if the stress is not too severe coral have been known to recover.  But often the story is more like a Shakespearian tragedy; the coral dies and never recovers.

In recorded history (which isn’t very long) we have had three global bleaching events. They occurred in 1998, 2010, and one is currently ongoing (that is July 2016 for those reading in a post-apocalyptic future trying to figure out what the hell went wrong with the world), set to be the longest mass bleaching event yet. Guess what causes it…That’s right, climate change! These events have all been triggered by El Nino weather events, but given the rate of temperature increase we are seeing, it may not be very long before triggers are not needed to cause mass bleaching events. We often focus on the atmospheric consequences of our despicable appetite for burning fossil fuels, but given that the oceans absorb 93% of the heat and approximately half of the carbon dioxide we emit, maybe we should consider how that’s going to effect the thing that covers the vast majority of our planet. Coral bleaching is one of these consequences; they simply cannot cope with the warmer oceans. And if they try to recover, the added carbon dioxide that has been absorbed makes the oceans more acidic and actively dissolves new coral that is trying to grow. In the Great Barrier Reef 93% of corals have been hit by bleaching. And it’s a similar story all across the globe.

But why should I care? I’m not a diver, so I can live without these coral reefs and brightly coloured fish. Except I can’t. While these corals account for 0.1% of the world’s ocean floor, they help keep approximately 25% of marine species alive. This, in turn, means that the livelihood of 500 million people and $30 billion is at stake, because for some reason people only care about the environment when you relate it back to humans. It’s not like we should just stop killing things unnecessarily, right?

So there you have it, a quick article this time. Coral bleaching is occurring all over the globe, it’s caused by human induced climate change, and has severe consequences for the oceans, the planet, and the people that inhabit it. We should probably stop this whole “polluting the planet” thing now; it’s not that funny anymore.

-James


header image courtesy of XL Catlin Seaview Survey via globalcoralbleaching.org

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