Dear English-speaking readers, this page is an automatic Google translation from a post originally written in French. My apologies for the weird sentences and the funny mistakes that could have been generated during the process. If you can read French, the original and correct version can be found here:
Dozens and dozens of lights appear in the darkness, as if by magic. The reef seems even more alive and more mysterious, more fascinating than in daylight.
Fluorescence is a funny thing. It is not about "bioluminescence" as with glowworms and other critters capable of generating their own light in the dark. It is also not about "phosphorescence" created by a mineral (phosphorus), as with the needles of a watch that shine in the night after being exposed to a light source.
No, fluorescence is the ability of some organisms to return bright colors (green, yellow, red) when they receive a particular light: the so-called "black" light, that of UV and some range of blue.
It is a protein who performs the magic trick, capturing photons and sending others back. Why ? We do not know exactly yet: to protect ourselves from UV rays, to attract prey or to repel predators, in response to a stress situation ... Researchers are still working on the subject.
It seems that the parts of the reef where intense growth occurs are the brightest. And, in fact, one quickly finds coral "heads", polyps, and a whole lot of lighter spots even in the coral debris supposedly "dead". So many clues that show that life is at work everywhere ...
To see and photograph the fluorescence of coral and the underwater world, special equipment is needed. Dex, the Canadian who runs the Kri Eco Resort Papua Diving with his companion Melanie, gave me an express course, very informative, and helped prepare my box for this incredible dive.
It is necessary :
a special blue light lamp to cause the fluorescent reaction
a yellow-orange filter on the porthole to filter this blue light so that the camera or camera captures only the light emitted back by the fluorescent organisms
a mask with the same yellow-orange filterfor the same reason, the sensor being this time ... the eyes. Without an orange filter, you can not see the fluorescence!
The self-adhesive film placed on the glass of my porthole has filled its office (filter blue light), but the next time I do a fluo-diving, I will try to get a real filter, because the transparency of the film in plastic is not perfect, impossible to get the beautiful sharpness that I'm used to with my 7D, yet powerful in low light.
But whatever. These first fluo images, even imperfect ones, give a good idea of the fabulous spectacle that the reef reserves under a blue light ...
Immersion in another world
At first, it's a bit confusing compared to a "normal" night dive. I would advise to be already familiar with the night dives before attempting a fluo dive.
Better to know how to manage your buoyancy without even thinking about it and be comfortable with your equipment in the dark. Each luminous point catches the eye, captures all the attention and tends to forget the rest on the periphery.
It's an immersion in another world. A spectacle of stunning beauty. There is something magical about seeing the light and the life in liquid darkness, wherever one directs his blue lamp.
Corals draw fabulous abstract paintings, banal lizardfish become electric green metamorphose into monsters of another time, scorpionfish glow in the night, polyps seem tiny hands endowed with consciousness ...
To learn more about fluorescent diving and the phenomenon of fluorescence, I refer you to these sites:
In "googlisant" the terms "fluo diving" or "coral fluorescence" you will find a lot of literature on the subject. Diving centers are more and more numerous to offer these very special night dives. Do not hesitate, if you have the opportunity to test. It's really a fantastic experience!