Plankton

Uael was right, after all.

Our guide during the Iwahig river trip did some magic with his paddle. He stuck it into the river, swirled the water with it, and made the river sparkle. 

He explained it was because of bio-luminescence. The plankton in the river had chemicals inside their bodies similar to those of fireflies'. When disturbed, they let out light.

Back to Uael. He said the same thing awhile back during out trip to Anawangin. We were swimming in the night and were amazed at the water glowing every time we splashed around. He explained it was because of plankton. I, on the other hand, was convinced it was simply something to do with the water ripples refracting and magnifying ambient light.

Turned out I was wrong. Hehe.