I have to admit, I was a little disappointed that the entirety of Laguna Grande didn’t glow bright blue. Photos taken showing things like this are a) amazing, b) taken with better cameras than my iPhone and likely special UV filters or photoshopping, and c) a bit of false advertising. However, after that initial letdown faded, I found myself smiling and laughing like a little child, awestruck at the wonder of nature.

Laguna Grande is just that, a large lagoon, connected to the ocean by a long, narrow, and winding channel just outside the eastern Puerto Rican town of Fajardo. Fajardo sits about an hour outside of San Juan, connected by a couple of well maintained highways as part of a ring around the island’s coastal areas. The drive there is scenic, though it would be more so if the sun weren’t already down, and I resolve to make this journey again during daylight hours on a future trip.

After a brief safety tutorial – basically, don’t flip the kayak or open the valve in the bottom of it – our group of about twenty gets into two-person vessels, each armed with glowing bracelets taped to the front and back. (It is totally dark at this point, so without these, it would be tough to see the kayak in front of you. Even with them, there are frequent soft and unintentional rammings.) Our five guides take their positions, one in front, one in back, and the others spread out through our single file formation, and we head down the channel toward Laguna Grande.

The channel runs through a thick mangrove forest. One of our guides explains the importance of the mangroves to the bioluminescence process. Mangroves are fairly unique. They are able to take in salt water, filter it, and spit the salt back out. So the waters of both the channel and the lagoon have a higher salinity than the ocean. This makes for an ideal environment for dinoflagellates, single-celled marine plankton. These plankton absorb the sun’s light during the day. And while, sadly, they don’t just glow all night, they do give off their light as part of a defense mechanism when agitated.

Moonlight on Laguna Grande

Soon, everyone in the group is dipping hands into the water – or oars, though they lack fingers to truly mix the water rapidly – to watch the process. For microseconds, the water around each splash lights up with what seems to be tiny lightning bugs. Some claim the light glows blue; others – like me – just see white, although I have a remarkably blue-glow photo that I can’t really explain. The process is so fast that even those with more professional cameras cannot capture it. Of course, it also doesn’t help that it was a full moon only a few days ago. The glow is brightest in the complete dark, so we all paddle into the thickest part of the mangroves to see a bit better.

Photo taken from Thrillist, and obviously taken by a much better camera.

The trip itself is beautiful, the glow of the moon on the water of the lagoon every bit as pretty as the bioluminescence. It is dark, peaceful, shared only by the occasional “rival” kayak tour company and their groups.

I can’t explain this blue glow in front of the kayak, so I’m going to assume I did a great job finding some bioluminescence! (The round glow is the bracelet taped to the kayak itself, and the red/green is the back of a guide in front of me.)

And, oh, the stars. So many stars!

Stars as seen from an iPhone camera. Not bad!

Laguna Grande is one of only five year round bioluminescent bays in the world. Three are here in Puerto Rico; Mosquito Bay on the Puerto Rican island of Vieques is the brightest. (The other two are in Jamaica and Vietnam’s Halong Bay.) Additionally, there are a number of bays that experience seasonal or occasional bioluminescence. Salinity, tidal conditions, sunlight, biological factors, and sheer luck contribute to these being the only ones.

The tour takes about ninety minutes all in all, most spent kayaking the channel, dodging low hanging branches – no small feat in the dark – and each other’s kayaks. It is a fairly easy kayak, not needing much in the way of exertion, as there is nearly no disturbance on the calm waters.

A slightly blurry shot of our guide lighting up the mangroves

So no, the waters of Laguna Grande don’t glow blue in the way I had expected and hoped. But they glow. And you will, too, if you experience one of the coolest things the natural world has to offer.

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