LIVING LIGHTS
LIVING LIGHTS
written and illustrated by
POOJA CHAUDHARY
This book was printed for the purpose of a college project titled ‘The Living Visual Project’ during the course of Semester 7. The brief of the project was to work within the realm of biology and apply to it the skills and knowledge of visual communication to develop a final outcome. This book is a brief introduction to the world of bioluminescence in the oceans of the world. The journey has been long and one of turmoil, but nonetheless worthwhile. So I’d like to take this opportunity to thank all those who’ve helped me along the way - you know who you are. And to the readers, I hope you enjoy the book as much as I enjoyed making it. Printed and bound at Kolor Kode, Bangalore 2016 Copyright © Pooja Chaudhary 2016
for K, without whom this book would never be complete
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As the sun goes down and the stars begin to show, a whole new world begins to awaken. Bats and owls roam the skies in search for food and fireflies blink on trees on warm summer nights. You’d think that everything else remains in absolute darkness except for a few creatures,
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But in the dark depths of the ocean, where everything seems black, an underwater glow, a fleeting gleam of light makes the ocean shine.
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Just like the fireflies in the skies, scores and scores of marine animals gleam with lights that are mostly blue, sometimes green and rarely even yellow. Scientists call this ability bioluminescence.
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biolumine [bahy-oh-loo-muh-nes-uh-ns]
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escence
n.
the production of light by living organisms Some creatures, especially in the ocean have evolved ways of being able to make light. They use this light to catch prey, attract mates, scare of predators, communicates and even hide. While most of these bioluminescent creatures live in the deep sea like the anglerfish, some can be found near the coast and even on land, like fireflies. In the deep sea, it isn’t only fish that glow. There are jellyfish, octopuses, squids, bacteria, eels and even worms that can produce light.
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DINOFLAGELLATES
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Dinoflagellates are unicellular plankton that live in almost any possible aquatic environment, whether they are fresh water or salt water - in oceans, rivers, lakes and even sea ice. They are so tiny that you cannot see them without a microscope. But inspite of being so tiny, sometimes they can multiply so much that they can cause red tides.
but without harming it at all. While the host animal gives it energy. the dinoflagellates give it the power to glow in the dark.
A number of these dinoflagellates sometimes live in other animals as symbiotic partners. The host animal swallows them and makes them a part of its tissues,
They are also capable of bioluminescence for which they are called ‘fire plants’. Each plankton begins to glow as it gets dark but will glow even brighter when
Dinoflagelletes are noteworthy for several reasons the primary reason being that they are the basis of the food chain, especially in the oceans.
agitated, like if a ship passes by. Even strong waves can make then glow. A chemical called luciferin is the reason it can glow at all. A dinoflagellete will continue to glow till its entire store of chemical is over. When the sun rises, it will recharge itself, like a battery and glow again at night.
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cephal [sef-uh-luh-pod]
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lopod
n.
a type of mollusc Molluscs are invertebrate animals and live mostly in aquatic or damp habitats. Slugs, snails, cuttlefish, mussels, squids, octopuses, oysters and clams are all different kinds of molluscs. Out of these, squids, cuttlefish and octopuses are specifically cephalopods. Cephalopods are different from other kinds of molluscs because they have large heads, tentacles and can squirt ink.
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A bobtail squid hatchling catching bioluminescent bacteria
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BOBTAIL SQUID The bobtail squid is a tiny cephalopod, not longer than your little finger, which lives in the shallow waters of the Pacific and Indian Oceans. It spends all day hiding in the sand and comes out at night to hunt. But while hunting, it also has to avoid being eaten by its predators. So to avoid being found, it shelters a certain bioluminescent bacteria on its underbelly to mimic the moonlight. Due to this, the predator cannot see the squid’s shadow and so it remains hidden. But the squid is not born with these bacteria. The hatchlings of the squid must carefully select these bacteria from the thousands of other micro organisms in the ocean. To catch these bacteria, the hatchling secretes a mucus that attracts all kinds of micro organisms. But still, it has to choose that one specific bacteria that will allow it to glow. Even today, scientists don’t know how these hatchlings do it, but miraculously these bacteria beat all the others that are stuck on the mucus. You would think that’s all it takes but after they have won, they still need to pass a few more tests till the hatchling’s body completely accepts them, Once the bacteria becomes a part of its body, the squid feeds it while the bacteria helps it to hide. They live together in symbiotic relationship.
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photop [foh-tuh--fohr]
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pores
n.
a tiny light emitting organ on the bodies of various marine animals. They look like tiny dots glowing with light on the bodies of fish and cephalopods. A lot of deep sea creatures have these light organs that they use to either hunt prey or confuse its predator. It is the photopores that contain the chemicals or the bioluminescent bacteria that the creature needs to be able to produce light, and so without them, no animal would be able to glow.
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Firefly squids glowing in the dark
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FIREFLY SQUID Of all the bioluminescent life forms in the ocean, the tiny firefly squid is another cephalopod which has a marvellous display of lights. There are thousands of photopores on its body that glow a deep blue colour. Like a firefly, it flashes its lights to attract small prey and then pounce on them with their powerful tentacles. Not only does its bioluminescence help it to get its next meal but also to find a mate and confuse its predator. Although these squid live deep in the ocean, in the summer they gather in Toyama Bay in Japan to lay eggs in the water. During this time, fishermen go out to catch these squids as they are a delicacy in Japan. As these fishermen drag out their catch, the ocean begins to glow a bright cobalt blue. The sight is so spectacular that people travel from all around the world to see this happen.
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Vampire squid squirting bioluminescent mucus
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VAMPIRE SQUID The vampire squid is a deep sea cephalopod which spends most of its time in aphotic parts of the ocean. Life is so slow here that it barely even needs any food. Instead of hunting for other creatures, it uses its two long sticky filaments to collect floating particles called marine snow. Marine snow is basically bits and pieces of dead plants and animals that float around in the water. This creature is quite unique because not only is it the only surviving member of its order, but it is also similar to octopuses. In fact, when it was first found, people thought it was an octopus! But unlike an octopus, it doesn’t have an ink sac. Instead when it feel extremely scared, it throws out a cloud of glowing, bioluminescent mucus from the tip of its arms. But usually, it simply turns inside out, like your clothes, to scare off other animals. It also has photopores on its body that it can turn on and off, like the firefly squid, but the ones near its eyes and the tip of its arms are more complex than the others.
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BRISTLEMOUTH FISH The bristlemouth fish is a tiny bioluminescent creature that lives in the dark ocean waters of the Indian, Pacific and Atlantic Oceans. It barely grows longer than your finger. These fish are so many of them that scientists say they outnumber humans quite easily! In fact, there are even more bristlemouth fish in the world than rats!
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Like most other deep sea fish, the size of its mouth is much bigger when compared to its body. This helps it to feed on a variety of sea creatures more easily. This is essential because in the zone that it lives, there is barely any food and so it must make sure that it can catch anything that it encounters if it has to survive. So how does this fish find its food in the first place?
Like the vampire and firefly squid, the bristlemouth fish also has photopores on its body. They are located on their bellies and sometimes on the underside of their heads. These pores either glow red or green. But unlike the vampire and firefly squid, it uses these lights to attract other small fish and crustaceans. When a prey passes close enough, it open up its mouth extraordinarily wide, baring needle-like fangs.
This strange little fish makes up for its tiny size with staggering numbers, as well as a behavioural trick or two. It starts life as a male and, in some cases, switches to become a female. Scientists call it protandrous. This ability helps out the bristlefish just in case there are no females around to mate.
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COOKIECUTTER SHARK The cookiecutter shark is a kind of dogfish shark that lives in the deep ocean waters and is one of the smallest kind of shark in the ocean. It comes up to the warmer waters in the night time to feed. This shark doesn’t eat by killing its prey, which are much much bigger than it. Instead it takes a bite out of its prey and swims away. Whales, dolphins, tuna, marlins, sting rays and even other sharks get naturally attracted to it because of its green bioluminescent underbelly. The glowing area makes it look like a small fish when you see it from below. This makes the larger fish think that they can easily prey on it and so they come closer to eat it. But just as they are about to bite the cookiecutter shark, the large fish is unexpectedly bitten by the shark. The cookiecutter shark attaches itself to its prey with its sucking lips and sharp pointy upper teeth. Once it is attached, the small shark twists and turns its body. It then removes a cookie-shaped piece from the flesh of its prey with its larger bottom teeth. The prey is left with a perfectly round cookie cutter-shaped hole in the side of its body. But this trick works only if the shark moves upwards, otherwise it can easily be detected by its predators as well.
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ANGLERFISH The anglerfish is the most commonly known bioluminescent creature in the ocean. You might have seen it in the movie ‘Finding Nemo’ and perhaps remember it as a black, demon like scary fish with large teeth and a bulb hanging from its head. Although this is slightly true, some anglerfish are even pink. But unlike the brownish ones, these live in much shallower waters. Most anglerfish live in the deepest parts of the ocean, where there is barely any food, very little oxygen and so much pressure that if you were to go there you would become a pancake! To be able to survive in such a difficult environment, it does a lot of things differently. To begin with, it isn’t fussy about food at all - it’ll eat just about anything that it can find. It swims upside down to save energy and has skin that reflects blue light. Amazingly, since most bioluminescent creatures emit blue light, the angler fish becomes invisible to them in the dark water.
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But its most complex adaptation is the esca that it has developed to catch prey. The esca is like a fishing rod with a light at the end. Bioluminescent bacteria in the esca produce a greenish blue light that attracts other fish and crustaceans living in the ocean. When they get close enough to the esca, the anglerfish opens up its larger mouth and eat it all up! Interestingly, only the female anglerfish has an esca. The male anglerfish, on the other hand, has a sensitive sense of smell which it uses to find a female. He then latches himself onto her and gets the energy he needs to live from her body. In return, he makes sure that he can allow her to make baby anglerfish whenever she is ready to.
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A split view of an atolla jellyfish in the light and glowing in the dark
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ATOLLA JELLYFISH The atolla jellyfish is a deep sea crown jellyfish, which means that the bell of the jellyfish, instead of looking like an umbrella, looks like a crown. It lives in the deep ocean all around the world. Like every other crown jellyfish, the atolla jellyfish are bioluminescent. This jellyfish flashes light like a police car when it is scared and because of this habit, it has been nicknamed the alarm jellyfish.
mislead, or distract its predators with the light that it produce. But mostly it uses its bioluminescence to lure or dazzle its next meal. The light attracts a crustacean or other organic matter that is passing by. With its one long tentacle, which is much much longer than the others, it grabs onto its prey before digesting it.
If a predator gets too close, its bell lights up. Otherwise, the bell of a crown jellyfish looks transparent when undisturbed. It tries to startle,
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atolla jellyfish
anglerfish cookiecutter shark
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TO SCALE firefly squid
vampire squid
bobtail squid
bristlemouth fish
dinoflagellates
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glossary aphotic (n.) the portion of the ocean where there is little or no sunlight pg. 18
plankton (n.) Extremely small creatures drifting or floating in the sea or fresh water. They can be either plants or animals. pg. 1
crustacean (n.) a very large group of arthropods (invertebrate animal having an exoskeleton) which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill, woodlice and barnacles
red tides (n.) sea water that becomes toxic and an odd red in colour when too many dinoflagellates grow in it pg. 1
pg. 20, 24
hatchlings (n.) a young animal that has recently emerged from its egg
symbiotic partners (n.) Two or more living things in a special relation in which they help each other out to survive in some way or the other.
pg. 12
pg. 1, 12
mucus (n.) a slimy substance. You can see it coming out of your body through your nose when you have a cold or cough
unicellular (n.) an organism that consists of only one cell
pg. 12
order (n.) one of the ranks that animals and plants are classified into in the study of biology. Order is sixth in sequence after life, domain, kingdom, phylum and class. pg. 18
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pg. 1
But in the dark depths of the ocean, where everything seems black, an underwater glow, a fleeting gleam of light makes the ocean shine.