Things that amaze me No 2 - Bioluminesence

I’ve decided to start a new blog series on things that simply amaze me. I’ve got a list of 25+ topics (at the moment) so I hope you’ll enjoy reading and learning about amazing things. Things that amaze me No 2 – Bioluminesence – things that light up!

And do, please, tell me the things that amaze you, too! If we share an amazement, I might blog about it!

Bio-luminescence is very cool – and useful!

Bioluminescence amazes me!

I have swum in a lake where my skin lit up like you see in the picture above. A truly amazing experience.

Throughout history, many cultures have told stories of people and beings wreathed with halos or imbued with an irrepressible brilliance: gods, angels, fairies, saints, and jinns. To be infused with light is to be divine or supernatural, precisely because it is an impossibility for us.

There’s a very interesting podcast on the history of bioluminescence you can listen to here. The podcast includes some fascinting stories about how bioluminescence saved the life of an astronaut and revealed the location of submarines during wartime.

Being “all lit up” appeals to many. Despite the best efforts even by people who decide its a good idea to sew LEDs beneath their skin in order to backlight tattoos it doesn’t match bioluminesence for impact. I have never seen this in real life, but if you google blacklight tattoos you’ll discover millions of examples, like these. Nice try, guys.

There are many naturlly bioluminescent animals and plants. Why is it so, I wonder? Here’s some brief summaries I discovered.

What is bioluminescence?

The history in fascinating. 2000 years ago Roman naturalist and philosopher Pliny the Elder wrote that one could rub the slime of a certain luminous jellyfish, possibly Pelagia noctiluca, onto a walking stick to make it double as a torch. (Note: don’t try this – the Pelagia noctiluca sting can be extremely painful and the effects can be long lasting as you can see the scar tissue on the shoulder of the person above. As recently as August 5, 2020 swarms of the Pelagia noctiluca have been seen off the coast of Devon. For more on this phenomena watch this news item. )

In the late 17th century, the physician Georg Eberhard Rumphius described indigenous peoples of Indonesia using bioluminescent fungi as flashlights in the forest.

Before the 19th century, coal miners filled jars with fireflies, as well as dried fish skin crawling with bioluminescent bacteria, to serve as lanterns – the safety lamp had not yet been invented and carrying an open flame into a cave risked igniting explosive gas.

I didn’t realise how vast the population of bio-luminescent animals and plants there were until I started reading about them. It would seem to the untrained eye that there are bioluminescent properties in every area of fauna and fauna. I wrote a whole list of them here and the list was so long that I deleted it! Trust me you can find bioluminescence in bacteria (micro-organisms), invertebrates, fish, terrestrial animals, freshwater animals, and plants of course.

Why do they do it?

There are all sorts of reasons for an animal to create its own bioluminescence, it may be as a defensive function to startle predators, counter-illumination (camouflage), misdirection (smoke screen), distractive body parts, burglar alarm (making predators easier for higher predators to see), and a warning to deter settlers – and offensive functions like to lure, stun or confuse prey, illuminate prey, or alternatively for mate attraction.

Bioluminescence is used as a lure to attract prey by several deep sea fish such as the anglerfish.

A dangling appendage that extends from the head of the fish attracts small animals to within striking distance of the fish.

The cookiecutter shark uses bioluminescence for camouflage, but a small patch on its underbelly remains dark and appears as a small fish to large predatory fish like tuna and mackerel swimming beneath it. When these fish try to consume the “small fish”, they are bitten by the shark, which gouges out small circular “cookie cutter” shaped chunks of flesh from its hosts.

Dinoflagellates have an interesting twist on this mechanism. When a predator of these little plankton is sensed by their motion in the water, then the dinoflagellate luminesces. This in turn attracts even larger predators which then consume the would-be predator of the dinoflagellate.

Plankton can be responsible for bioluminescence by shooting a bioluminescent liquid into the water rather than illuminating themselves. It is thought that this lightshow is an evasive action to distract predators. Plankton may use their bioluminescence to shine bright and attract a mate.

Plankton will gather energy from the sun, store it during the day and then release it at night for maximum effect. The agitation of breaking waves will often create bioluminescence as a halo effect surrounding islands and along coastlines. The experience you can see below is when surfers moved through the waters at San Clemente. Watch the video and see this in action!

This was similar to our own experience on the Gippsland lakes years earlier.

In some cases the bioluminescent function simply isn’t known. Scientists haven’t worked out yet why three families of earthworm (Oligochaeta), produce light when they move. There are many more similar questions to answer. Look at these beautiful examples!

Interestingly, some plants have been altered by scientists to emit an eerie green glow, they look like foliage from a retro computer game! But in fact they are light-emitting plants produced in a laboratory. It all contributes to our understanding of the phenomenon.

Researchers say the glowing greenery could not only add an unusual dimension to home decor but also open up a fresh way for scientists to explore the inner workings of plants. They even hope to replace street lighting with this technology some time in the future.

There’s an interesting blog about how luminescence happens locally here in Australia in the very own Gippsland lakes my family and I were visiting. Phil Hart has written about this on numerous occasions in the last few years. Read more here. These are his images.

Want to experience bioluminescence on your next holiday?

If you’d like to see bio-luminescence in an ocean one day, there’s a website to help you locate some to assist in your planning for your next holiday. Here’s the link. Let me know how you go. This is what you might see if you visit Japan at the right moment!