SCIENCE

National Geographic Emerging Explorer David Gruber found a secret world under the sea—and it glows. His expeditions have turned up hundreds of shimmering creatures, all showing off for one another with a mysterious fluorescence. It’s an underwater display that had never been seen before. (National Geographic News)

Use our resources to learn more about marine creatures’ “Living Light.”

Teachers, scroll all the way down for a short list of key resources in our “Teachers’ Toolkit.”

Discussion Ideas

• Read through our activity “Bioluminescence: Living Light.” What is different about the habitats of the creatures discussed in the activity and habitats of the creatures David Gruber studied?
  • The organisms discussed in the activity are native to the cold, dark, deep sea. The animals studied by Dr. Gruber live in warmer, shallower, moderately moonlit coral reefs.

• What is the difference between the bioluminescent glow emitted by the creatures in the activity, and the biofluorescence studied by Dr. Gruber and his colleagues? Think about the different marine habitats, and read through our encyclopedic entry on bioluminescence—just search for “fluorescence”—for some help.
  • Biofluorescence requires “some ambient light,” according to the Nat Geo News article. The ambient (surrounding) light is absorbed and re-emitted. The biofluorescent light is only visible in the presence of the ambient light. In the coral reefs studied by Dr. Gruber, the ambient light comes from the Moon.
  • Bioluminescence, on the other hand, is an entirely self-contained chemical reaction and does not require any light at all. Most bioluminescent creatures are native to the deep sea—too deep for sunlight (or moonlight) to penetrate.

• The amazing biodiversity of coral reefs has been studied for centuries. Why hasn’t anyone ever noticed that familiar creatures as stingrays or soles glow in the dark?
  • Because their glows are invisible to the human eye. To “see” like a fish, Dr. Gruber uses a yellow filter on his camera that mimics the lens in a fish’s eye. “There’s a hidden layer of pattern and color that humans are just tuning in to,” Dr. Gruber says. “It’s a whole new way for us to perceive, and better understand, life in the sea.”

TEACHERS’ TOOLKIT

Nat Geo News: David Gruber: Seeing the Ocean in Neon

Nat Geo Education activity: Bioluminescence: Living Light

Nat Geo Education encyclopedic entry: bioluminescence

Nat Geo glossary:
bioluminescence
fluorescence
ambient

(extra credit!) PLOS ONE: The Covert World of Fish Biofluorescence: A Phylogenetically Widespread and Phenotypically Variable Phenomenon