What is coral bleaching?

I’m sure you all have heard many stories about the effects of climate change recently,  so here’s one that I was unaware of until now. The ecological issue I will be talking about is coral bleaching. The rising water temperatures due to climate change are causing a phenomenon that is hurting many ecosystems due to eliminating a key player, which is coral reefs. To survive, coral reefs depend on their symbiotic relationship with tiny, one-celled organisms that are similar to algae, called zooxanthellae. The little organisms make a big difference in the reefs; they live within the tissues and give the coral nutrients using photosynthesis. They also happen to be what gives the coral its colouration. In return, the coral gives the zooxanthellae carbon dioxide and ammonium, needed for photosynthesis. Because of climate change, the ability of the coral to give back to its helper is challenged, and the coral instinctively kicks the zooxanthellae out of its tissue. This causes the discolouration of the coral, and because the zooxanthellae provided nutrients, the coral may start to die.

The ecosystem that is affected is the sea life that depends on coral reefs to hide from their predators. According to the National Oceanic and Atmospheric Administration, About 25% of the ocean's fish depend on healthy coral reefs. Fishes and other organisms shelter, find food, reproduce, and rear their young in the many nooks and crannies formed by corals. Now, of course, this doesn’t only affect the fish population. Think about it; if there are less fish, then the animals that eat fish are also affected. And the animals that eat those animals are also affected. This creates a long domino effect but in total, most of the animals that are affected by coral bleaching are fish, plants, invertebrates, sea turtles, marine mammals, and birds. That’s a lot of organisms!

But that’s not even the end of the problem. We, humans, are affected too! As the National Oceanic and Atmospheric Administration states, coral reefs protect coastlines from storms and erosion, provide jobs for local communities, and offer opportunities for recreation. They are also are a source of food and new medicines. Over half a billion people depend on reefs for food, income, and protection.

So I guess it really is a full circle, isn't it? We, the humans who are causing climate change, are also being negatively affected by it. And no, I’m not one to hide behind my computer screen and point fingers because, as The Good Place (a great TV show) got correctly, it is getting harder and harder to be a good person in today’s world. Our life is based on decisions that big businesses make and that we have no say in, and are sometimes completely unaware of. For example, when you go to the grocery store and want to buy a snack, there is no big label that says “Hey, this product relies on fossil fuels to be mass-produced!”. There are lots of things that are just out of our control. That doesn’t mean that you can’t do anything though. Shopping local, relying less on single-use products, and driving a more efficient car (and driving less obviously) are all things you can do to make a change.

Learn more about this phenomenon with my favourite page (here) and video on the subject (here)

Sources: NOAA, Wikipedia, Marine Conservation

Photo by milan degraeve on Unsplash