Climate change: How it affects coral reefs

-By Christoffer Nilsson


A coral is an invertebrate animal with its skeleton on the outside, similar to shellfish. The corals extract calcium and carbonate from the seawater to build their skeleton. They live in symbiosis with a photosynthetic algae called “zooxanthellae”, which means that they benefit from each other. The algae produce sugars for the coral, and corals produce nutrients for the algae.

In tropical areas, coral reefs are very sensitive and are easily affected by climate change, specifically by rising seawater temperature and acidification of the oceans. Just 1-2 degrees change in sea water temperature affects the corals, causing them to expel the algae “zooxanthellae” making the coral turn completely white (bleaching). The corals can survive this if seawater temperature goes back to normal quickly. Coral reefs are very important to the marine environment as almost a third of all marine species live there. About 60% of the all the world’s reefs are estimated to be at risk due to climate change.

Since coral reefs host home for a third of all marine species it also plays an important role for humans living in these areas as they provide food for them. Nearly 500 million people depend in some way by coral reefs through fishing tourism or protection. I can only imagine what would happen if the reefs started to diminish even more. The situation is much worse than I previously knew. Even if the article states that around 500 million people are affected in some way I think the entire ecosystem will be gravely affected by the diminishing coral reefs which means that everyone on the planet is affected.
The article does not mention anything about how tourism and scuba diving affects the corals reefs but it is not hard to conclude that climate change is the biggest threat to the coral reefs.

Scuba divers may damage corals locally, but dive-related damages are usually quite small so the impact on the marine ecosystem as a whole is relatively low. Scuba divers are often restricted to specific areas and when comparisons have been made to areas where little or no scuba diving is being carried out the damages are the same. Tourism however is a bigger concern and scuba diving is in a way a part of this. Tourism increases global warming since a lot of “transportation” of people is being carried out, people are travelling the world in much greater scale every year which contributes to increased emissions of greenhouses gases.




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