This is not your average night dive. You float weightless in darkness; the seafloor is a mile below; a single light suspended on a downline beckons unknown creatures from the void. This is blackwater diving, and it's an increasingly popular activity at dive destinations around the world.
The appeal of blackwater diving is small – very small. It's about catching a glimpse or snapping an image of the miniature creatures that rise from the depths each night to feed near the surface. Marine biologists call it vertical migration. It happens in oceans worldwide, and it's the greatest simultaneous moment of life on Earth, involving billions of individual organisms.
Decades before recreational blackwater diving became a thing when French scientists descended into the nighttime waters of the Mediterranean to collect marine life samples. The practice caught on in California and Hawaii, and in addition to taking samples some researchers started capturing images of the weird and wonderful things that showed up under their dive lights. In 1982, author Christopher Newbert published the first collection of these images in his book Within a Rainbowed Sea.
It would take another 20 years for blackwater diving to catch on with recreational shooters. The game changer was the advent of high-quality digital cameras sporting high-resolution monitors. Instead of squinting through a small viewfinder and hoping for the best with a 36-exposure roll of film. Digital shooters could put their rigs into low-light mode and fire ways, filling image cards with hundreds of possibilities.
Today, blackwater diving has spread to destinations around the world, from Palm Beach Florida and Cozumel to Hawaii, Palau, the Philippines, Indonesia, Tahiti and beyond. All that is needed is a site where deep water runs within a reasonable distance of shore. Underwater photographers are the driving force behind the modern blackwater diving trend, but it also appeals to some non-shooters with a bit of curiosity and a sense of adventure.
A blackwater excursion begins well after sunset when all surface light is gone. Dives are conducted from a free-drifting boat, and divers enter the water and descend to depths of 30 to 60 feet to hang motionless in the glow of a central light source suspended from a surface float. This light does double duty, illuminating marine life while also serving as a fixed vertical reference point in a realm where it's easy to lose track of depth.
What's there to see? Some of the most fascinating finds are larval fish. Many species of both pelagic and reef fish spend their early days hiding in the depths, rising each night to feed, then making a return descent before sunrise. These tiny specimens often look nothing like their adult counterparts. Many have translucence bodies that make them nearly invisible in dim light. When illuminated by the beam of a dive light, they present a shimmering profile that makes for an intriguing portrait.
Numerous species of shrimp, squid and octopus are also revealed by underwater lighting. Some display an eerie bioluminescent glow that reveals their presence in the dark waters beyond the glow. The darkness may also be lit by the faint glow of bioluminescent zooplankton – tiny jellyfish, crustaceans and other organisms. Lights may capture larger jellyfish feeding on this protoplasmic soup.
Blackwater photo buffs devote all their attention to capturing the small and sometimes bizarre creatures revealed by underwater lighting. Camera-free divers who are along for the experience may want to divide their attention between the small stuff and the pelagic hunters that sometimes show up in the glow to capitalize on the a meal they would have otherwise missed. The possibility of glimpsing a swordfish or a shark circle on the edge of the glow adds an element in intrigue to what is otherwise described as a relaxing and ethereal experience of weightlessness and detachment from the everyday world.