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Kilimanjaro Preserves Coral Reef

Cool water run-off from the mountain is enabling a 150 square mile reef to thrive with colourful coral and an abundance of marine life.

Marine biologists are constantly on the look out for coral refuges - places where coral reefs have the best chance to survive warming waters due to climate change. The good news is that researchers have recently discovered an incredibly rich coral refuge on Africa's east coast, off Kenya and Tanzania.


The coral refuge is thriving. It's teeming with spinner dolphins as well as rare species such as coelacanths - a species of fish that was once believed to be extinct - and it's also home to dugongs, a rare and elusive marine mammal that's similar to a manatee.


So, how is it possible for this coral refuge to exist when all around it other reefs are suffering from coral bleaching due to warming waters? The answer is, remarkably, Mt. Kilimanjaro.


The coral refuge stretches 50 miles from Mombasa, Kenya to Dar es Salaam, Tanzania - whilst in parallel on land, it's home to the majestic Mt. Kilimanjaro and its neighbouring Usambara mountains. Apparently, the glacial runoff from these mountains feeds into the ocean through deep channels that have formed over millennia, providing cool water to protect the corals from episodic warming events like El Niño.


“It turns out there is a long stretch from Kenyan waters into Dar Es Salaam where these warm water events like El Niño don’t penetrate. So the stress killing corals does not penetrate. Outside that area, the corals are bleached and dying. But inside the area, of around 400 sq km [150 sq miles] they retain their colour and their health. They are reds and brown. My research partner likes to call them: ‘happy corals’,” said Tim McClanahan, the author of the study published this month in Advances in Marine Biology.


“Our study shows that while warming waters may devastate surrounding reefs, this area could become an incredibly important sanctuary where marine species big and small will flock to find refuge from climate change,” “If well protected, this key transboundary marine ecosystem will remain a jewel of biodiversity for the entire east African coast.”


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