A Trip to the Depth of the Oceans — The Twilight Zone
Travelling can be pretty fun, but what if we are travelling to the depths of the ocean where we can only survive for 10 minutes? What do we need to know? Read on and find out!
“No matter the sorrow
No matter the cost
That not all who wonder
or wander are lost”
One cannot go through more than ten stories on social media without stumbling on the word “wanderlust”. In that spirit, we decided to take a trip ourselves, but unlike most travellers, we didn’t go up the mountains and read a book sitting outside while sipping on a hot cup of coffee. Instead, we went to visit the old gods, deep in the bowels of the ocean, to the place where even light does not dare enter, where the ecosystems are so different that one might think they have entered another dimension, where death lurks around in a constant inevitability. If this seems like an exciting prospect to you — for the love of god, are you insane? We are talking about a place where you make one small mistake and you wouldn’t be able to see the sun ever again; but go on if you want to — let us tell you what you might need and what you might see when you take this perilous journey.
First and foremost, the one thing you need above all is a strong heart; if you have that, well, continue ahead and see for yourself the wonders that the ocean holds for you! Now, before travelling to any place, it is always good to know a little about it because you don’t want to end up in a ditch somewhere, which, to be honest, has a very high chance here. So to learn about our place of travel, let’s understand a little about our majestic oceans:
We all understand that oceans cover 71 per cent of the earth, but what we fail to grasp is the depth of the oceans. At the deepest part, it extends to around 10.994 kilometres. To put it in perspective, the height of the tallest mountain on earth, which is Mount Everest, is 8.89 kilometres. In general, the average depth of oceans is around 3700 metres, which for the purpose of studying oceans, is divided into three zones based on how far the light reaches:
Sunlight Zone, or the Epipelagic Zone, extends down to 200 metres and covers only 5 percent of the depth. This zone is our sweet spot for scuba diving or other activities that one usually looks forward to on vacation.
Twilight Zone, or the Mesopelagic Zone, extends up to 1000 metres and covers around 20 percent of the depth. This is the spot we are looking forward to parking our vans at and looking around.
The Deep Ocean is further divided into the Midnight Zone, the Abyss and the Trenches. It covers the rest of the ocean, covered in darkness. If you thought the Twilight Zone was an adventurous place to go, the Deep Ocean is going to haunt your dreams even during waking hours.
Now that we know a little about our destination and its surroundings let’s learn more about the Twilight Zone and why it isn’t going to be like tanning on the beach.
Understanding the danger -
Twilight Zone lies in a sweet spot between the well-studied Sunlight Zone up ahead and the abyss of darkness down below. Spanning around 800 metres, it is a reef deficient of plant life, a kingdom of plankton-eaters and CARNIVORES (are you still ready to take the journey?). To be honest, the zone isn’t just full of scares; it is also necessary for sustaining the earth’s ecosystem. The Twilight Zone plays a major role in removing carbon dioxide from the atmosphere and keeping it stored for centuries (I don’t think we need to tell you how important that is in today’s changing climate). The Mesopelagic Zone teems with a variety of marine life. In their profuse and bizarre biodiversity, the ocean’s Twilight Zone resembles nothing so much as an undersea island. Since Darwin, biologists have recognized that terrestrial islands are cauldrons of speciation, as science writer David Quammen once put it, “geographical isolation is the flywheel of evolution.” Just as the Galapagos teems with unique finches and tortoises, so does the ocean’s Twilight Zone, churning out endemic species by virtue of their solitude (and much more). And so, we occasionally disturb this solitude to study and catalogue what lies in the depths, far away from the gods above.
How to survive -
Since carnivores weren’t enough to deter you, let’s go further and learn how diving will work at such depths. The pressure at such depths is enough to cause serious injury or death, but if you think that is the worst-case scenario, we have a surprise for you. The pressurised environment turns the air toxic — normal oxygen concentrations induce seizures. At the same time, nitrogen can become a narcotic so disorienting that adding two and two on your fingers feels like trying to make sense of the Kardashian family tree. Apart from these, time is also your enemy; if you go deep and spend more time, your body’s tissue absorbs more nitrogen and increases the risk of the dreaded bends (decompression sickness, caused by the growth of nitrogen bubbles in bloodstreams during too-rapid ascents). The maximum time you can spend (assuming you have had the training to be a professional diver) is around 10 minutes, which sounds like a short vacation.
Now to surmount those toxic effects, you need to breathe a specially mixed cocktail of gases whose primary ingredient is helium. To explore this zone, you will need a battery of finely calibrated gear. Rebreathers recycle every exhalation; scrubber canisters capture off-gassed carbon dioxide by converting it to calcium carbonate; computers inject precise puffs of oxygen into air hoses. And even then, you would need to carry at least 3 tanks in case the others fail. Jeez, talk about over-preparation, but here, it is the bare minimum!
Sightseeing -
Well, let’s assume after taking care of everything, we get a safe 10 minutes in the Twilight Zone. We have our rebreather, and we have our spare tanks; it is now time to have a look around and see the species that rule this zone. Since light rarely reaches here, it is difficult to see anything, but we have some man-made technologies with us to help out, and maybe some species are just too eager to show themselves. If you think the species we are about to discuss are fictional, we promise you we don’t have enough nightmares to bring them to life.
As we move deep into the ocean, the familiar species look and behave differently. Familiar hard corals yield technicolour soft-bodied corals that wave in the current like a Seussian fever dream. Parrotfish and rabbitfish cede to luminous basslets and google-eyed squirrelfish. And some creatures lie in wait for their prey to walk over so that they can hunt them without moving around. Exciting, isn’t it?
But the big question is, how does this ecosystem without any sunlight sustain life? The answer is the corals in the deep are hunters, albeit passive hunters snagging plankton as it floats by. In contrast, corals in the shallows rely on symbiotic solar-powered algae for energy. Some creatures live in a symbiotic relationship with bioluminescent bacteria, and some develop their own ways to survive this eternal darkness. Still, most come to the surface at night to hunt. Let’s meet some of the creatures that might greet us on our journey to the Twilight Zone.
Anglerfish:
Scientific Name Oneirodes eschirchtii; Also known as Dreamer, Bulbous Dreamer, Cosmopolitan Dreamfall -
We have all seen piranha movies and have nightmares about them, but anglerfish puts those to shame. These basketball-sized fish have a gaping mouth and gnashing teeth and a glowing lure dangling from a rod on their forehead. The light source on this bulbous appendage, or “esca”, is bioluminescent bacteria. In order to glow, the bacteria need some sort of cue from the anglerfish — suggesting a symbiotic relationship between the fish and microbes.
So scary enough? Or do we need to explore more? Okay, looks like you’re up for it. Let’s see some more!
Strawberry Squid:
Scientific Name Histioteuthis heteropsis; Also known as Cock-eyed squid, Jewel squid -
Don’t be confused by the name; this creature might sound cute but is nothing like that; it is named for strawberry-coloured cells called photophores that dot its skin and provide its distinctive glow. Its semi-upright posture lets the strawberry squid simultaneously look up, down, and sideways as it jets through the ocean. So if you are planning to distract it? Forget it; they can see you like the Big Brother.
Bristlemouth:
Scientific Name Cyclothone sp.; Also known as Longtooth anglemouth
Bristlemouths are small fish that glow in the dark and have large mouths full of gnarly fangs. If you thought humans have a large population? Bristlemouth may shock you. They are the most numerous vertebrates on Earth, with hundreds of trillions or even quadrillions swimming in the twilight zone. So if it was all humans vs all Bristlemouth? I would bet on these scary creatures (of course, if the fight is in water.)
Some pleasantly surprising sites…
We think we have frightened you enough but there is a surprise waiting for you. You might get lucky enough to encounter one creature who you wouldn’t think would ever inhabit this zone. This creature is the Emperor Penguin — yeah, you read correctly! The cute, fluffy-looking penguins who waddle through life. Emperor Penguins, even though they breathe air and live on Antarctic ice, sometimes visit the deep middle zone of the ocean in search of food, or to avoid becoming someone else’s food. The penguins are excellent swimmers, with solid bones and a super efficient circulatory system which helps them endure the crushing pressure of water. Emperor Penguins conserve their oxygen by slowing down their heart as slow as fifteen beats per minute. What magnificent creatures!
Will you undertake this dangerous sojourn to the inky depth of the ocean? Yes or No?
Now that you have in front of you the list of things you need to keep in mind while venturing into this dark side of the ocean, the question is: are you bold enough to go there? Are you brave enough to breach the limits of human endurance, embrace the cool, crushing embrace of the deep ocean — where you can only hear your thoughts, where anything can go fatally wrong and end your life — to see the mysteries of the deep blue expanse which cover our earth? The decision is yours. We hope we have prepared you well for this dangerous yet exciting journey. Bon Voyage!
This article was written by Muskan Garg, and Atotmyr and edited by Vagisha Bhatia.
References -
Smithsonian | Science.org | Nasa | Twilight Zone | Wired | QZ | Ocean Service | Nature | Vox | PopSci | Earth.com
