National Geographic : 2015 Mar
Luminous Life 85 darkroom. On a table, in a small dish, is another example of living luminosity... Several months after the voyage on the Western Flyer, I visited Vieques, a small island that belongs to Puerto Rico. The island is famous for its bahía bioluminiscente, or “bio bay”— a flask-shaped inlet that is home to countless dinoflagellates, those speck-of-dust-size beings that light up when the water is disturbed. The night is dark. The moon has not yet risen, and the island has just a smattering of streetlights, so the sky is full of stars. I am sitting in a transpar- ent canoe, here as part of a tour—one of several tonight. Our group has eight canoes, two people in each; I’m sharing mine with a lawyer from Washington. We’re “parked” in the middle of the bay, looking at the dark sea and the starry sky, and listening to the guide explain the challenges the place faces—increasing numbers of tourists, and rising light pollution as more houses and roads get built on the island. Although there are few streetlights now, their impact is noticeable: The edge of the bay away from the lights is visibly darker, the flashes from the dinoflagellates vis- ibly brighter. While the guide talks, a fish darts through the water; it looks like a meteor. Now we’ve started moving. Our canoe has fallen behind the group, and I have the illusion we are out here alone. As we paddle forward, the movement of the canoe disturbs the microbes, and they light up in a bright, flickering stream. Watching them through the transparent floor of the canoe, I have the powerful impression that the water is part of the sky, and we are paddling through the stars. j MORE ONLINE ngm.com/more In a long exposure, bioluminescence creates streaks of light from the backs of three Brazilian click beetles. They use light to attract mates and, perhaps, to scare off potential predators. ELATERIDAE VIDEO Why do some mushrooms glow?