Photo of the Day: Bioluminescence is produced naturally when chemical energy is emitted as light instead of heat. This process makes fireflies blink, and phytoplankton (seen here) glow. . . . #POTD #photooftheday #picoftheday #ScienceSunday #phytoplankton #bioluminescence #pretty #glow #fireflies #weird #truefacts #strangebuttrue #nature #naturephotography #sciencephotography #longexposure #HDR #wildlife #landscape #landscapephotography #travel