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Find out more about UNSEEN, our projects and our images. Do not hesitate to contact us if you need any further information or if you wish to collaborate with us. You can now immerse yourself in the hidden wonders of the deep coral reefs of the Twilight Zone, also called Mesophotic Coral Ecosystems!

But wait… Deep coral reefs, Twilight Zone, Mesophotic Coral Ecosystems… What is that?

We all have this picture of colourful coral reefs, with plenty of fish swimming around. The fortunate ones even had a chance to explore them during snorkelling or diving trips in the tropics. They are the most studied coral ecosystems, as they are relatively shallow and therefore “easy” to access. But life doesn’t stop at 30 metres, the limit of recreational scuba diving. Between 30 to sometimes as deep as 150 metres, coral reef ecosystems can also be found! They are the deep coral reefs, rarely studied due to the difficulty to access those depth. We generally call this area the Twilight Zone, because the natural sunlight hardly reaches it. But corals are still thriving there and the colours are stunning, even in the darkness!

Mesophotic Coral Ecosystem (MCE) is the other - more scientific - name, for describing an environment where light-dependant coral communities and associated organisms are developing.

Why is it important to study MCEs?

As they are poorly studied, very few people are aware of their existence. Consequently, they are rarely taken into consideration during management plans like the establishment of Marine Protected Areas for example. But they host their own biodiversity and they are important for many marine organisms, at various stage of their life cycles. Some animals can only be found there, they are endemic to MCEs.

A vertical connectivity exists between MCEs and the more famous shallow reefs. Because of this vertical connection, some fish might find in MCEs a refuge from human pressure in the shallower waters (e.g. fishing, diving, pollution). Indeed, human pressure tends to diminish with depth. Because they are deeper, the water is also usually cooler. So the deep coral colonies can be less impacted by bleaching events linked to high temperatures… Thanks to this, MCEs can in some cases act as a lifebuoy for degraded shallow water reefs. Indeed, corals that are found both in shallow reefs and MCEs can survive the bleaching periods in the deeper cooler part of the reef, and regrow the degraded shallow water part once the water temperatures are back to normal.

There are many more reasons to learn more about those crucial ecosystems. We believe that by showing those natural wonders to public, people will be more likely to feel connected to them and willing to protect them. We believe at UNSEEN that conservation can come from awareness, as the better we know, the better we can preserve.

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