Dear English-speaking readers, this page is an automatic translation made from a post originally written in French. My apologies for any strange sentences and funny mistakes that may have been generated during the process. If you are reading French, click on the French flag below to access the original and correct text:
Dozens and dozens of lights appear in the darkness, as if by magic. The reef seems even more alive and mysterious, more fascinating than in the daytime.
Fluorescence is a funny thing. It is not "bioluminescence" as with glow worms and other bugs able to generate their own light in the dark. It is not "phosphorescence" created by a mineral (phosphorus), as with the hands of a watch that shine in the night after being exposed to a light source.
No, fluorescence is the ability of some organisms to send back bright colors (green, yellow, red) when they receive a very specific light: the so-called "black" light, UV light and a certain range of blue light.
It is a protein which performs the magic trick, capturing photons and sending back others. Why does it do this? We don't know yet exactly: to protect itself from UV rays, to attract prey or repel predators, in reaction to a stress situation... Researchers are still working on the subject.
It seems that the parts of the reef where intense growth takes place are the brightest. And, in fact, we can quickly spot the coral "heads", the polyps, and a whole bunch of small lighter spots even in the debris of supposedly "dead" coral. 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 partner Melanie, gave me an express course, very instructive, and helped me to prepare my tank for this incredible dive.
You have to:
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 only captures the light emitted by the fluorescent organisms
a mask with the same yellow-orange filterfor the same reason, the sensor this time being... the eyes. Without an orange filter, it's impossible to see the fluorescence!
The sticky film placed on the glass of my porthole did its job (filtering the blue light), but the next time I will do a fluo-diving trip, I will try to get a real filter, because the transparency of the plastic film is not perfect, impossible to get the nice sharpness I am used to with my 7D, yet powerful in low light.
But who cares? These first fluorescent images, even if imperfect, give a good idea of the fabulous show that the reef offers under a blue light...
Immersion in another world
At the beginning, it is a bit confusing compared to a "normal" night dive. I would advise you to be familiar with night diving before attempting a fluorescent dive.
It is better to know how to manage your buoyancy without even thinking about it and to be comfortable with your equipment in the dark. Each point of light catches the eye, captures all the attention and tends to make you forget the rest on the periphery.
It is an immersion in another world. A show of staggering beauty. There is something magical about seeing light and life emerge in the liquid darkness, wherever you point your blue lamp.
The corals draw fabulous abstract paintings, the banal lizardfish become electric green and metamorphose into monsters from another time, the scorpionfish glow in the night, the polyps seem like tiny hands endowed with consciousness...
To learn more about fluorescent diving and the phenomenon of fluorescence, I refer you to these sites:
By "googling" the terms "fluo diving" or "coral fluorescence" you will find a lot of literature on the subject. More and more dive centers are offering these very special night dives. Don't hesitate, if you have the possibility to try it. It is really a fantastic experience!