When people think about climate change, the link with melting glaciers and polar ice caps is quickly made. Way fewer people make a link between climate change and dying coral reefs. However, coral reefs are heavily affected by acidification and rising temperature of oceans worldwide. Time to dive into this! Read more in the article below.
Coral reefs and their place in ecosystems
Although they occupy less than 0.1% of the ocean floor, corals are crucial for healthy oceans. Coral reefs support a whopping 25% of marine species—that’s more species than tropical rainforests!
Reefs provide shelter, food, and breeding grounds for marine life, while also serving as natural barriers that protect coastal communities from hurricanes and tsunamis.
But what is coral?
Corals are tiny animals (polyps). They live in large colonies and protect their delicate bodies, by using minerals from the seawater to build a limestone skeleton. All these skeletons together form what we know as coral reefs.
On these skeletons live algae. These algae are vital to the coral's survival, as they provide up to 90% of the coral's energy through photosynthesis and give the corals their vibrant colors. A true symbiotic relationship.
And an amazing thing about coral: they take in CO2, and release oxygen.
Oceans & CO2
Oceans take up more carbon from the atmosphere than anything else. Almost one-half of all the CO2 released into Earth’s atmosphere by human activities, has been absorbed by the oceans.
But as the ocean absorbs more carbon, its waters become increasingly acidic. Since the Industrial Revolution, ocean acidity has surged by 30%, pushing coral reefs to the brink of collapse. And this process weakens coral skeletons, killing algae, and triggering mass coral bleaching. When this happens, the coral reefs die.
One of the areas where this is happening at a huge scale, is the Great Barrier Reef. Nearly 80 per cent of coral outcrops had bleached here, according to a report from the Australian government.
Another reason for the coral reefs bleaching are rising water temperatures, due to global warming and climate change. When water temperatures rise, the coral become stressed and expels its zooxanthellae. And with this, the coral becomes prone to disease and starvation.
Leticia Carvalho, the Head of the Marine and Freshwater Branch of the United Nations Environment Programme (UNEP): “The loss of corals would be a true tragedy from a biodiversity and economic perspective. It would be devastating for one of the richest ecosystems on our blue planet and hundreds of millions of people around the world who depend on coastal fisheries.”
What to expect?
Over the last three decades, the world has lost half of its reefs. Scientists predict that we could lose over 90% of our coral reefs by 2050, if we don't act urgently to reduce our greenhouse gas emissions. This is truly a climate emergency.
Oceans cover over two-thirds of our planet and play an essential role in stabilizing global temperatures. Without healthy reefs, the entire marine ecosystem—along with the communities and economies that depend on it—will degrade.
Time to protect coral
But the good news: bleaching is not always fatal for corals. If water temperatures cool quickly enough, the animals can recover.
So, also in this context it is very important to reduce our CO2-emissions. And protect and restore the coral reefs that are already damaged.
Hedgehogs Clara and Max spoke with Mike Odenhoven, Co–Founder of Sumthing. Sumting works on nature-restoration, in a transparent & reliable way. Coral Reef restoration is one of their major areas of focus.
Read more about this on Sumthings website, or listen the podcast episode Technologie, transparantie & natuurherstel (in Dutch) on Spotify or Apple Podcasts.
Sources
https://www.britannica.com/science/ocean-acidification
https://www.wwf.org.uk/coral-reefs-and-climate-change
https://www.unep.org/news-and-stories/story/worlds-corals-are-bleaching-heres-why-and-what-it-means-oceans-future
