Swimming in bioluminescence

Based on 16.02, Galapagos (San Cristobal).

The third time we walked out to Playa Punta Carola that day, we needed our phone torches to find the way. The long wooden pier ran through the mangroves to the water’s edge, and beyond it the little rocky bay sat black and still under a sky so clear the Milky Way was out. By daylight this was one of San Cristobal’s best snorkelling spots, a small protected bay we already knew well. At night it was another place entirely.

We knew it a bit too well, if anything. We had snorkelled there earlier, and I had gone back that evening for another swim and been thoroughly spoiled: turtles, penguins, sea lions, the full Galapagos cast. Steffi had skipped that one. As far as we were concerned, the bay had already shown us everything it had, and we were back at the hostel making two minute noodles.

That is where the English traveller found us. She told us her story in the hostel kitchen: a local had wanted to take her on a date, and his pitch was that he knew a cool place to see bioluminescent plankton that very night. She had googled it, found the spot, and invited us along with a British friend of hers. The local, in the end, never turned up. So instead of a date, four of us set off into the dark with phone torches.

There was some moonlight, but not much. When we reached the end of the pier we switched the torches off and just stood there for a while, heads tipped back. The stars were astonishing. I spent a good stretch of time fiddling with camera settings, trying to hold the Milky Way still long enough to photograph it, and then we all sat down near the water to wait.

Someone stirred the water, and the sea answered.

Little blue specks appeared where the water moved, glowed dimly for a moment, and immediately went out again. It only happened with motion. Splash your hand through the shallows and a scatter of faint blue points followed it, then the black closed over them like nothing had happened. Steffi found it magical but very hard to see, and had to bring her face right down to the surface to catch it properly. From the wooden steps beside the water’s edge, the others flicked water back and forth, chasing the glow.

I decided the only sensible thing was to get in.

There was no debate on my side. Steffi’s side had a longer list: the water was dark, she knew how many fish and creatures were around, there were rocks and algae everywhere, nobody could tell how deep it was, and she had washed her hair only a few hours earlier. So she stayed on the steps, and I went down them alone and slipped into the sea.

The water was calm and somewhat cold, but not freezing. That is roughly the last practical thought I had. From inside the water, the glow was a different thing altogether. Every movement I made lit up around me. The plankton were invisible until touched, and my arms and legs were touching thousands of them. The best of it came when I rolled over and swam backwards, because then the water flowed over my whole body and the specks came flying over me, streaming across my chest and shoulders and trailing off into the dark. Above me was the Milky Way. Around me, a dimmer, moving version of the same thing. The glow lived and died with movement; the moment the water stilled, it all went black again.

I stayed in for about fifteen minutes. Earlier that evening, this exact stretch of water had handed me turtles, penguins and sea lions, and it had still been holding something back. Now it was quiet out in the bay, the others splashing at the steps somewhere behind me, and I just kept sweeping my arms through the black water to watch it answer.

Then I climbed out onto the pier, dripping, and we packed up the camera and walked the short way back to the hostel by torchlight. It was, on paper, an entirely uneventful walk.

People who have seen bioluminescence at its best describe whole bays lit up blue, waves glowing as they break. Ours was the faint version, the kind you have to put your face against the water to see, and we still hope to catch the bright kind somewhere one day. Not that we would plan a whole trip around it. But some nights I still think about rolling onto my back in that dark Galapagos bay, stars above and sparks below, watching the water answer every move I made.