Question 1

What is the difference between Bioluminescence and Fluorescence?

Accepted Answer

Bioluminescence generates its own photons chemically and works in total darkness. Fluorescence merely absorbs incoming light and re-emits it at a longer wavelength, so it needs an external source. Most 'glowing coral' photographs are fluorescence, not bioluminescence.

Question 2

How do I know if I mean Bioluminescence rather than Fluorescence?

Accepted Answer

Readers who land here meaning Bioluminescence rather than Fluorescence are usually searching for phrases like “how does bioluminescence work”, “why do sea creatures glow”, “bioluminescence vs fluorescence”.

Aspect	Bioluminescence	Fluorescence
Needs a light source	No	Yes
Works in the dark	Yes	No
Energy from	Chemistry	Incoming light
Coral photos	Rarely	Usually

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Bioluminescence

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