Bioluminescence is a phenomenon that occurs when organisms glow on their own. Through internal chemical reactions, animals like jellyfish and fireflies produce light, and many of these organisms live in bodies of water, collecting in large quantities to create a glow in the water. Bioluminescent creatures can create a spectacle of blue-colored light in five bays in the world, and Puerto Rico holds the most bioluminescent bays in the world.
When people take boats into the bays, they can see a glowing blue trail where their boat moves and glowing blue outlines of fish as they swim in the water.
Puerto Rico has three bioluminescent bays—Laguna Grande, La Parguera, and Mosquito Bay. To light up at night, these bays contain dinoflagellates, or dinos. Dinos are microscopic, single-celled organisms that are bioluminescent and live in Puerto Rico. When any sort of movement occurs in the waters of the bays, the dinos activate their bioluminescence and light up. This phenomenon occurs because the dinos use their bioluminescence as a defense mechanism; any movement causes the dinos to glow. When people take boats into the bays, they can see a glowing blue trail where their boat moves and glowing blue outlines of fish as they swim in the water.
Mosquito Bay is “the brightest bioluminescent bay in the world” containing “an average of 1,000,000 to 2,100,000 [dinos] per gallon of water.” Mosquito Bay is protected from light pollution, so only natural light is allowed to enter the bay, allowing the dinos to shine much brighter. I’ve been to Mosquito Bay myself, and I can state that it’s an amazing experience. If anyone is planning on going to Puerto Rico in the future, I’d highly recommend visiting Mosquito Bay or another bioluminescent bay.