Ocean Glow
DB: This is Earth and Sky. Christopher Springman of Pt. Reyes, California asks: “Why does the ocean glow at night?”
JB: Christopher, the ocean itself doesn’t actually glow, but plenty of things that live in it do. The light they emit is called bioluminescence, and there are hundreds of different kinds of organisms on Earth that create it. Most of them live in the sea.
DB: One kind of bioluminescence that many people are familiar with appears as sparkling streaks of light at the bow and in the wake of a moving boat in the ocean at night. The light comes from tiny, single-celled algae called dinoflagellates that live in seawater.
JB: Water agitation prompts the light-giving chemical reaction in the dinoflagellates. Most light comes off as bluish, but different chemicals produce different colors. In the case of dinoflagellates, the intensity of light depends on the concentration of algae in the water. In some places, like the Indian Ocean, sailors have reported a soft white glow on the surface of the water – a “milky sea” that stretches as far as they can see.
DB: Other types of bioluminescent organisms include fireflies, centipedes, fungi, squid, jellyfish, worms, and some fish. That’s our show. Thanks for your question, Christopher.
JB: And thanks today to the National Oceanic and Atmospheric Administration, and to the National Fish and Wildlife Foundation. We’re Block and Byrd for Earth and Sky.
The following people were interviewed for today’s program. Our thanks to:
William Patzert
Research Scientist
Oceanography Group
Jet Propulsion Laboratory
NASA
Gene Carl Feldman
Oceanographer
NASA/Goddard Space Flight Center
For more information:
Bioluminescence web page (Univerity of California Santa Barbara)
Harbor Branch Oceanographic Institute’s bioluminescence page
Additional Teacher Resources
University of California Santa Barbra, The Bioluminescence Web Page: The Bioluminescence Web Page
This site provides a variety of information on ocean bioluminescence and the species that cause it. It includes sections on how bioluminescence works, physiology, chemistry, organisms and myths.
Duke University, Ocean Chemistry: Natural Product Chemistry from Marine Organisms
Have you ever seen waves crashing at night flash a green light? This greenish glow, known as bioluminescence, is light that is emitted from dinoflagellates, a type of marine plankton. This report explains the chemistry and natural history behind dinoflagellates and bioluminescence.
National Geographic for Kids: Go With The Glow
This site is a good resource for younger students. This brief article explains dinoflagellates bioluminescence in terms all students can understand, as well as providing interactive links, photo images, and maps.
