Nature’s Glow: The Illuminating World of Bioluminescence

Anyone remember this scene in Pixar’s “Finding Nemo” when Dory and Marlin swim down to the deepest depths of the ocean and are confronted with an anglerfish aglow with rage?

Well, that furious fluorescence is an example of bioluminescence – one of the most strange and complex of adaptions seen in nature. Bioluminescence is the ability for an organism to produce it’s own light. Bio- Latin for life and lumen- Latin for light (and inspiration for the Harry Potter spell Lumos). It is found naturally in several species, the most famous being the deep-sea anglerfish a’ la Finding Nemo.

The deep-sea anglerfish (nicknamed “Sea-Devil”) predominately uses bioluminescence to attract prey. Imagine floating around in a jet-black abyss completely blind to your surroundings, a tiny glowing light suddenly appears. You’d be a little curious to find out where it’s coming from, would you not? That’s what the anglerfish is betting on anyway. The female anglerfish possesses a modified glowing dorsal spine that hangs above their mouth, a siren call luring curious creatures straight into their mouths.

But, in fact, the lady anglerfish aren’t producing any of this light themselves; the actual hard work is being done by scores of bacteria housed with the fish’s dorsal spine tip. It is a symbiotic relationship; the anglerfish provides the bacteria with food and shelter, which in turn allows the bacteria to carry out chemical reactions. The chemical reaction gives off light as a product and there you go: the living, swimming glow-stick!

Many marine creatures have the ability to produce light: crustaceans, jellyfish, sea stars, worms, fish, sharks and octopus to name a few. The bioluminescent octopus, for example, has “photophores” all over its body. These photophores can be turned on and off to create a twinkling effect that last for a few minutes. Scientists believe there are several advantages to this glowing: not only to lure prey but also to deter predation and even to attract mates.

Speaking of attractive, bioluminescent plankton may not sound like the most awe-inspiring of creatures, but on a dark night at a Jervis Bay beach they can be just that. As millions of the plankton are washed towards to the coastline, the movement of the waves triggers the single- celled dinoflagelletes inside the organisms to light up and glow. The result is an ocean that appears to mirror the Milky Way above, an entire cloak of glittering, swirling stars being pushed up towards the beach. This phenomenon occurs in a range of places all over the world if the conditions are just right.

As for terrestrial organisms, glowworms and fireflies are key examples of bioluminescence in effect, but do any mammals produce their own light? Well naturally, no but technically, yes. In 1995, scientists at Stanford University used genetic engineering techniques to insert the genes responsible for bioluminescence into salmonella bacteria and feeding this altered bacteria to lab mice. The scientists could then track the pathway of the bacteria through the mice’s body and by doing so created the first ever “bioluminescent mammals”.

The future use of bioluminescence and gene editing have become quite topical in recent years due to the possibilities it could provide for clean energy sources. Scientists have already created a glowing tobacco crop by the addition of the bioluminescent gene into the plant. This concept of a glowing plant: one that needs no batteries to run and very little money to maintain has sparked the imagination of designers and scientists worldwide. In the home for example, a glowing houseplant can replace a desk lamp but why stop there? Imagine roads illuminated by rows of glowing trees instead of street lamps. Not only would it be beautiful to witness it would be beneficial to the environment and low cost. There has always been debate, of course, about the ethical and moral responsibilities of gene editing, “how far is too far?”  …We will have to wait and see.

Bioluminescence in deep-sea organisms is both a biological and visual marvel. Whether or not the harnessing of this adaption will be beneficial to human kind and the environment is still a mystery. I, for one, am intrigued about the seemingly endless possibilities it could offer, but in the meantime am adding “watching a glowing ocean on the beach” to my bucket list.

First published on 10th June 2016 on RiAus – Australia’s Science Channel

Header image credit: Picture of the bioluminescence of the deep-sea zoanthid Gerardia, along with the bioluminescence of an unknown planktonic animal (as shot from the submersible). Notice how the planktonic light is bluer. Image courtesy of Bioluminescence 2009 Expedition, NOAA/OER

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