• Question: Do jellyfish really glow in the dark, or just in cartoons? :D

    Asked by petrinabean to Clare, Dave, Glo, Ozge, Sean on 20 Jun 2011.
    • Photo: Ozge Ozkaya

      Ozge Ozkaya answered on 20 Jun 2011:

      No they really do, and they are not even the only thing that glows. So many other organisms glow in the dark too. On land fireflies do the same. Also anglerfish (the really scary fish in nemo remember?) and even some bacteria produce light. Krill glows in the dark!! Some mushrooms even glow!

      The phenomenon is called bioluminescence (from greek bios=living and latin lumen=light). It is a chemical reaction that releases energy in the form of light. In nature bioluminescence is used for a number of purposes, to attract pray for instance, for camouflage, to repulse a predator, to communicate and illuminate! It is really cool stuff!

      In bioengineering we can use bioluminescense, believe it or not there are designer (transgenic) zebrafish that glow in the dark. We can use it as a measure of circadian (24h) rhythmicity. If we put the gene of the enzyme (luciderase) that catalyses the reaction that produces light under the promoter of a gene that is expressed rhythmically in fruitflies we see flies fluorescing on and off every 12 hours!!! How cool is that?!

    • Photo: Gloeta Massie

      Gloeta Massie answered on 20 Jun 2011:

      Cartoons have NOTHING on Mother Nature. Up to 90% of the animals in the deep sea glow in the dark, and a lot of them in the shallows do, too! Check out this awesome video on this topic – including the jellyfish that use bioluminescence to signal HELP!

    • Photo: Sean Clement

      Sean Clement answered on 20 Jun 2011:

      If you ever find yourself in a boat at night, or by the sea even, try running your hands through the water. What might happen is that you’ll see a trail of faint light in the ripples caused by your hand. This, as Ozge and Glo have said, is caused by bioluminesence from Planktonic organisms called Dinoflagellates. By creating a short and sharp (for something microscopic, anyway) burst of light, they hope to scare away whatever predator causing the disturbance (which, in the case, is your hand)

      Try it some time!

Comments