There’s a wholly different and mesmerising world, hidden in plain sight, at night, underwater. There are things that glow in the dark. It's called fluorescent diving and it all happens with the flick of a switch. 

That’s what we learnt in February this year when Mike Markovina of Moving Sushi introduced the Two Oceans Aquarium to Jacques Vieira, founder of the Fluorescent Shark Project South Africa [link goes to Facebook]. Their request was simple: could they come to the Aquarium after dark to find out what does, or doesn’t, fluoresce underwater? Our response was immediate: Please do!

Linda Markovina is a photojournalist and the other half of Moving Sushi, which is a team dedicated to all things ocean related … from filmmaking, journalism and photography to ground-breaking expeditions, fisheries science and ocean conservation. In this post, she writes about the fluo diving experience.

Photo by Ross Frylinck

Jacques Vieira and a small team made up of Moving Sushi and other ocean advocates, including Ross Frylinck of the Sea-Change Project, came to the Two Oceans Aquarium one night in February to investigate and discover more about fluorescing animals. Once all the tourists and visitors had left for the day, the Aquarium turned off the lights. There in the dark, when the blue lights were shone on the different shark and fish species, something spectacular happened. Things were fluorescing that had not before been understood to even be capable of such actions. Penguins fluoresced, and so did crabs, horsefish, seahorses and the small puffadder and dark shysharks darting between the kelp.

Jacques Vieira

What also became apparent is how little we know about this amazing fluorescing function. Sharks that we assumed must fluoresce, did absolutely nothing under the blue light, while other species, like some turtles, only fluoresced on certain parts of their bodies … And other turtle species didn’t fluoresce at all. This is the challenge that the  Fluorescent Shark Project South Africa now faces - there simply is not enough information out there. But therein lies the sheer wonderment of doing something new. Since there is so little information out there, the discoveries are potentially endless.

Photo © Mike Markovina

Jacques, a former resident of Gonubie in the Eastern Cape and now of Madagascar, started scuba diving at a very young age. His first sea dive was a birthday present from his dad, a dive shop owner, at the tender age of 10. Seeking his fortune outside of South Africa, Jacques travelled to Madagascar and eventually settled as the manager of a dive centre on the smaller island of Nosy Sakatia. No roads, no shops, just a secluded neighbourhood with lots of reefs right on its doorstep. Working and diving every day, he made a life for himself on the island, but it was only after watching the BBC series Oceans that he learnt about an interesting aspect of diving that he did not consider before: fluorescent diving.

Nosy Be in Madagascar, where Jacques is based, is a tropical island destination for divers the world over. They come in their holiday best to spend the days snorkelling over the shorelines of the different islands, watching passing turtles and whale sharks, swimming alongside reef fish and the coral-lined lagoons of this volcanic perfume island. It’s hard to imagine that it gets any better than this, but when the night rolls in and most people retreat to the shoreline for cocktails, more adventurous divers gather their kits and head out into the dark water. Because, out there, another diving realm for those who are looking for something a little unusual is waiting. The calmer nights of the northern tip of Madagascar is the perfect place to be introduced to a whole new way of looking into the ocean, and it all happens with the flick of a switch.

Photo © Mike Markovina

“After being inspired by the BBC series I did a lot of research on the subject of fluorescent diving and found a producer that makes the blue-light torches and yellow filters in the Netherlands and Germany,” Jacques recalls. “When I hit the water, what I saw blew me away. Once you have seen the underwater world under blue light and through a yellow filter, your mind floods with millions of questions, especially when you get to understand that this is actually how the animals of this underwater world see each other and communicate.”

Photo © Mike Markovina

Fluorescent or fluo diving refers to diving at night with the use of a small torch that emits a blue light, which you then shine over the reef or dive site. A blue light is used because it is at the very end of the visible light spectrum, between 450 and 470nm. Colours have wavelengths. The shorter the wave, the higher the energy. We know that violet has the "highest" energy with a wavelength of around 400nm and then blues (~450), green (~550) and finally reds (~650). That means that when going deeper red will disappear first, then greens, then blues and then violet...)

Photo © Mike Markovina

When you look at the resulting illuminations through a yellow filter on your dive mask, what you see is nothing short of an explosion of colour and light. It can be intimidating at first: heading out into the night water, sometimes very far out, where not much can be seen with the naked eye. But, when the blue light is turned on, the reef becomes an underwater disco. Yellows, greens, reds, purples and blues bounce off every fluorescent corner.

The fluorescence you are picking up with your torch is actually an emission of light by a substance that has absorbed light or other electromagnetic radiation and you see this as a form of luminescence (low-energy light) when you hit it with the blue light (higher-energy light.) The actual colour of the light we see through the tinted mask is determined by how many quantum states the electron has "decayed" or relaxed back to. What you end up seeing can be quite overwhelming.

Photo © Mike Markovina

A normally dense-looking brown patch of reef becomes a fireball of red and undulating electric blue. Crabs hiding underneath rocks, normally blending in with their surrounds, are unmistakable in their shockingly bright illuminations. The sides of small fish light up yellow and lightning white as they dart past your eyes. Gather up a small magnifying glass and you can spy on a macro world where corals turn into a super-structure of brightly lit-up parts.

Photo © Mike Markovina

The demand for this new kind of diving experience is gaining traction, but the real magic is happening in the world of science and the study of the creatures that do, or do not, light up and, most importantly, why this is the case. “This diving has been a big success back in Madagascar where I am the only one currently doing it,” says Jacques. “I started wondering what more could be done with this process. Being a passionate ocean advocate and having a vested interest in the life of the ocean, I had the idea of coming to Cape Town and starting the Fluorescent Shark Project South Africa, with the aim of understanding sharks from a new perspective in order to help protect them and add to the greater knowledge of these magnificent species.

Photo © Mike Markovina

“The challenges that I see are to focus on and limit the questions. It would be so easy to get lost in the maze,” Jacques reflected after the Aquarium dive. “I hope that I can dedicate my life to getting all the answers to the million questions I have, so that we can understand how the underwater world communicates. Understanding this complexity may then enable us to protect the marine environment in a better and more appropriate manner. I see myself dedicating every last moment to fluo and hope to spread the work along the entire South African coastline.”

Photo © Mike Markovina

With most of the earth’s surface covered by the ocean, it’s no wonder that we still know so little about what happens just below the surface. It is estimated that for every one marine species we know of, there are at least three that are yet to be discovered. We can only imagine the possibilities when we turn off the lights and see the ocean through a whole new spectrum - who knows what might still be out there?

More details of the work being done can be found on the the Fluorescent Shark Project South Africa’s Facebook page. You can contact Jacques on fluosharkproject@gmail.com.

Photo © Mike Markovina

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