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. 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, both visually and scientifically.
Fluorescence exploration data:
The expedition team will focus on three deployment strategies:
- Using the OpenROV trident underwater drone. By using the drone, the team can cover a larger area with the fluorescent torches at depths beyond diver accessibility (60 - 100 meters).
- Using BRUVs with fluo torches attached, sampling observations will take place at depth with a baited apparatus inviting predatory species into the camera field of view. Observations can range from shallow intertidal waters to depths of 90 - 90 meters.
- Diver based observations will be conducted in shallow waters and specifically focusing on coral and benthic species.