PRpod: Puerto Rico picture of the day

Discover Puerto Rico! Each day a different picture pertaining to the youth's tour of Puerto Rico is featured, along with a brief explanation and a few links for further investigation.

July 19, 2025

What is bioluminescence?

Bioluminescence is the ability of an organism to create light chemically. While relatively rare on land (fireflies can do it!), bioluminescence is very common in the ocean, especially in the gelatinous zooplankton, such as jellyfish, comb jellies, and other animals that are mostly made of water.
While usually blue in color, because that is the light that travels best through the water, bioluminescence can range from nearly violet to green-yellow (and very occasionally red).

Tomorrow's picture: Where are we going to be Ziplining?