"DEEPEST OCEANIC BENCH: THE MARIANA TRENCH"

     

     "JOURNEY TO THE BOTTOM OF THE EARTH Via MARIANA TRENCH"

                                      (By ANISHK YADAV, ENGINEERING STUDENT)

 

The Mariana Trench or Marianas Trench is located in the western Pacific Ocean about 200 kilometers (124 mi) east of the Mariana Islands; it is the deepest oceanic trench on Earth. It is crescent-shaped and measures about 2,550 km (1,580 mi) in length and 69 km (43 mi) in width. The maximum known depth is 10,984 meters (36,037 ft) (± 25 meters [82 ft]) at the southern end of a small slot-shaped valley in its floor known as the Challenger Deep. However, some unrepeated measurements place the deepest portion at 11,034 meters (36,201 ft). At the bottom of the trench, the water column above exerts a pressure of 1,086 bars (15,750 psi), more than 1,071 times the standard atmospheric pressure at sea level. At this pressure, the density of water is increased by 4.96%. The temperature at the bottom is 1 to 4 °C (34 to 39 °F). 

 

                   POINTS WE WILL BE COVERING IN THIS ARTICLE

1.   Preparing The Backpack For The Trench Dive

2.   Bathymetry Of The Trench And Its Descents

3.   Diving Into The Depth Of The Trench

4.   Facts About The Mariana Trench

5.   Inhabitants Of Mariana Trench

 

 

 

Preparing The Backpack For The Trench Dive

We Are Ready To Begin Our Long Journey Into The Depths Of The Mariana Trench. So For Such A Long Way, We Should Be Fully Prepared And Know Some Of  The Terminologies Which We Need Out There. So Let's Grab The Pieces of Stuff Which Will Be Useful To Us Throughout The Journey. And We’ve Got Some Exclusive Bonus For You As Well, So Stick Around:

·        What Is A Trench?

A  trench is a type of excavation or depression in the ground that is generally deeper than it is wide (as opposed to a wider gully, or ditch), and narrow compared with its length (as opposed to a simple hole). In geology, trenches are created as a result of erosion by rivers or by geological movement of tectonic plates.

·        What Is An Oceanic Trench?

Oceanic trenches are topographic depressions of the seafloor, relatively narrow, but very long. These oceanographic features are the deepest parts of the ocean floor. Oceanic trenches are a distinctive morphological feature of convergent plate boundaries, along which lithospheric plates move towards each other at rates that vary from a few millimeters to over ten centimeters per year.

·        What Is Challenger Deep?

The Challenger Deep is the deepest known point in the Earth's seabed hydrosphere (the oceans), with a depth of 10,902 to 10,929 m (35,768 to 35,856 ft) by direct measurement from deep-diving submersibles, remotely operated vehicles and benthic landers and (sometimes) slightly more by sonar bathymetry.

·         What Do You Mean By Bathymetry?

Bathymetry is the study of underwater depth of ocean floors or lake floors. In other words, bathymetry is the underwater equivalent to hypsometry or topography. The name comes from Greek word “Bathus” means "Deep", and “Metron” means "Measure". Bathymetric charts are typically produced to support the safety of surface or sub-surface navigation, and usually show seafloor relief or terrain as contour lines (called depth contours or isobaths) and selected depths (soundings), and typically also provide surface navigational information.

·        How The Oceanic Trenches Are Formed?

Oceanic Trenches are formed by subduction, a geophysical process in which two or more of Earth's tectonic plates converge and the older, denser plate is pushed beneath the lighter plate and deep into the mantle, causing the seafloor and outermost crust (the lithosphere) to bend and form a steep, V-shaped depression.

·        What Is Decompression Sickness?

Decompression sickness also called generalized barotrauma or the bends refers to injuries caused by a rapid decrease in the pressure that surrounds you, of either air or water. It occurs most commonly in scuba or deep-sea divers, although it also can occur during high-altitude or unpressurized air travel. What happens inside your body during decompression sickness is similar to what happens when you open a carbonated drink. When you open the can or bottle, you decrease the pressure surrounding the beverage in the container, which causes the gas to come out of the liquid in the form of bubbles. If nitrogen bubbles form in your blood, they can damage blood vessels and block normal blood flow.

·        What Is SOFAR or DEEP SEA CHANNEL?

The SOFAR channel (short for Sound Fixing and Ranging channel), or deep sound channel (DSC), is a horizontal layer of water in the ocean at which depth the speed of sound is at its minimum. The SOFAR channel acts as a waveguide for sound, and low-frequency sound waves within the channel may travel thousands of miles before dissipating. This phenomenon is an important factor in submarine warfare.

·        What Is Midnight Zone In The Trench?

Midnight zone, also known as the Bathyal zone or Bathypelagic is the part of the pelagic zone that extends from a depth of 1,000 to 4,000 m (3,300 to 13,100 ft) below the ocean surface. It lies between the mesopelagic above and the abyssopelagic below. The average temperature hovers at about 4 °C (39 °F). Although larger by volume than the photic zone, the bathyal zone is less densely populated. Sunlight does not reach this zone, meaning primary production, if any, is almost non-existent. There are no known plants because of the lack of sunlight necessary for photosynthesis. It is known as the midnight (also twilight or dark) zone because of this feature.

·        What Is An Abyss?

The Abyssal zone or Abyssopelagic zone is a layer of the pelagic zone of the ocean. "Abyss" derives from the Greek word "ávyssos" meaning "bottomless". At depths of 3,000 to 6,000 meters (9,800 to 19,700 ft), this zone remains in perpetual darkness. It alone makes up over 83% of the ocean and covers 60% of the Earth. The abyssal zone has temperatures around 2 to 3 °C (36 to 37 °F) through the large majority of its mass. Due to there being no light, there are no plants producing oxygen, which primarily comes from ice that had melted long ago from the polar regions. The water along the seafloor of this zone is devoid of oxygen, resulting in a death trap for organisms unable to quickly return to the oxygen-enriched water above. It is the deeper part of the midnight zone, which starts in the bathypelagic waters above.

 

·        BONUS!

§  The Kola Superdeep Borehole Which Is just 9 inches in diameter, but at 40,230 feet (12,262 meters) reigns as the deepest hole. It took almost 20 years to reach that 7.5-mile depth—only half the distance or less to the mantle. It’s Even Deeper Than The Mariana Trench.

§  Megalodon (Carcharocles megalodon), meaning "big tooth", is an extinct species of shark that lived approximately 23 to 3.6 million years ago (mya), during the Early Miocene to the Pliocene. It was formerly thought to be a member of the family Lamnidae and a close relative of the great white shark (Carcharodon carcharias). It Was Rumoured To Be Present In The Mariana Trench.

§  The sperm whale or cachalot (Physeter macrocephalus) is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus Physeter and one of three extant species in the sperm whale family, along with the pygmy sperm whale and dwarf sperm whale of the genus Kogia.

§  The first human to reach the 6.8-mile-deep (11-kilometer-deep) undersea valley solo, Famous Director James Cameron arrived at the bottom with the tech to collect scientific data, specimens, and visions unthinkable in 1960, when the only other manned Challenger Deep dive took place, according to members of the National Geographic expedition.

§  The Mariana Trench is named after the nearby Mariana Islands, which are named Las Marianas in honor of Spanish Queen Mariana of Austria, widow of Philip IV of Spain). The islands are part of the island arc that is formed on an over-riding plate, called the Mariana Plate (also named for the islands), on the western side of the trench.

§  Mariana Trench is 10,994 m deep, while Mount Everest is 8,848 m tall. The difference is 2,146 m, or at least no less than 2,104 m, accounting for the combined 42 m uncertainty in the measurements.

Bathymetry Of The Trench And Its Descents

BATHYMETRY Of THE MARIANA TRENCH:

v  The trench was first sounded during the Challenger expedition in 1875, using a weighted rope, which recorded a depth of 4,475 fathoms (8,184 meters; 26,850 feet).

v  In 1899, USS Nero, a converted collier, recorded a depth of 5,269 fathoms (9,636 meters; 31,614 feet).

v  In 1951, the Challenger II measured depth of 5,960 fathoms (10,900 meters; 35,760 feet) at 11°19′N 142°15′E, known as the Challenger Deep.

v  In 1957, the Soviet vessel Vityaz reported a depth of 11,034 meters (36,201 ft) at a location dubbed the Mariana Hollow.

v  In 1962, the surface ship M.V. Spencer F. Baird recorded a maximum depth of 10,915 meters (35,810 ft) using precision depth gauges.

v  In 1984, the Japanese survey vessel Takuyō collected data from the Mariana Trench using a narrow, multi-beam echo sounder; it reported a maximum depth of 10,924 meters (35,840 ft), also reported as 10,920 meters (35,830 ft) ±10 m (33 ft).

v  On 1 June 2009, sonar mapping of the Challenger Deep by the Simrad EM120 sonar multibeam bathymetry system for deep water, mapping aboard the RV Kilo Moana (mothership of the Nereus vehicle), indicated a spot with a depth of 10,971 meters (35,994 ft).

 

 

DESCENTS Of THE MARIANA TRENCH:  

Four manned descents and three unmanned descents have been achieved:-

§  The first was the manned descent by Swiss-designed, Italian-built, United States Navy-owned bathyscaphe Trieste which reached the bottom at 1:06 pm on 23 January 1960, with Don Walsh and Jacques Piccard on board. An iron shot was used for ballast, with gasoline for buoyancy. The onboard systems indicated a depth of 11,521 m (37,799 ft), but this was later revised to 10,916 m (35,814 ft).

§  This was followed by the unmanned ROVs Kaikō in 1996 and Nereus in 2009. The first three expeditions directly measured very similar depths of 10,902 to 10,916 m (35,768 to 35,814 ft). 

§  The fourth was made by Canadian film director James Cameron in 2012. On 26 March, he reached the bottom of the Mariana Trench in the submersible vessel Deepsea Challenger, diving to a depth of 10,908 m (35,787 ft).

§  Victor Vescovo achieved a new record descent to 10,927 meters (35,853 ft.), using the DSV Limiting Factor, a Triton 36000/2 model manufactured by Florida-based Triton Submarines. He dived again in May 2019 and became the first person to dive the Challenger Deep twice.

 

Diving Into The Depth Of The Trench

Ever wanted to dive into the deepest parts of the ocean? Well, today you’re gonna have this opportunity! Now, how good are you at holding your breath? Not that good? Well not to worry. Hop on board of my submersible words and join me in the voyage to the depths!

The Mariana trench begins at about 19,700 ft deep. It’s both the least explored and the most fascinating area for scientists and adventurers alike. The Challenger Deep is the bottom of the Mariana trench, and its depth is 35,853 ft.

Ready? Let’s dive!

~So we start from the ocean level where 90% of the ocean life resides. Ah, that's the place where you surf and dives into the ocean to meet the oceanic habitat( though the only ones which are visible to us, there's way too many vast mysteries lying down there).

- At 65 ft, there’s a whole new world opening before your eyes: shallow coral reefs are standing beautifully not far from the shore.

- 130 ft is the depth where we say goodbye even to recreational scuba divers  it’s the maximum allowed for them.

- At 230 ft we meet whale sharks  the largest known fish species, weighing up to 60 tons. And They Can Live up to 130 years.

-At 330 ft Professional Scuba Divers (they have to be very cautious not to get decompression sickness)

-At 415 ft If You're lucky you can also see a giant pacific octopus(it dwells in cool waters starting this deep and going down as far as 6600ft)

- At 490 ft, we’re entering the dark part of the ocean:  just 1% of the light from the surface reaches us. The rest is absorbed by water.

- At 660 ft you can see a giant oarfish circling your submersible. they are believed to be the source of all sea serpent sightings.

-At 800 ft, Its The Dive Depth of a Nuclear Submarine.

- At 980 ft you'll see a huge and gangling creature, A Japanese Spider Crab.

-1,044 ft, That's the Deepest Recorded Scuba Dive Ever.

- Going deeper now, and At 1,640 ft you’re going to see the last of the blue whales — no, not the least of them, I mean, that’s the deepest they can swim. The Fin Whales Makes Sounds In Deep Water To talk to their Friends many miles away Because of the SOFAR channel (Deep Sea Channel). Awesome right?

- At the depth of 2,723 ft, we have reached the point where the Burj Khalifa, the tallest building in the world, would not even show its tip on the surface if it were put underwater.

- At 2,950 ft No Sunlight can reach this point in the ocean And The giant squid inhabits in the depths. Just imagine the creature with eyes the size of frisbees!

- At 3,300 It's where the pitch darkness falls on us: The Midnight Zone. The pressure here is so huge that, if you somehow end up being here without a submersible, you’ll simply be crushed in a couple of seconds.

-At 3,600 ft there's West Mata: One Of The Deepest Ocean Volcanoes In The World. Its last eruption was in 2009.

- 4,200 ft down below, and we see the ferocious great white sharks. These ultimate predators feel great at such a depth. Their Eyesight is rather poor and they navigate through scent, so they don't need sunlight to hunt down their Prey. ("I Don't See You, But I'll Still Eat You"). Also, The Leatherback Turtles, the largest turtles in the world, dive at the same depth.

- At 4,900 ft you'll See some huge nets? That’s because we’re now at the depth of the ocean where the “catch-all” fishing method is used catching everything unfortunate enough to be caught.

- At 6,000 ft, if we were in the Grand Canyon, we’d be sitting at its lowest and deepest point. Imagine That all of its crevasses have been filled with water and you'll get the perfect scenario.

- Now, if we’re really careful, then at the depth of 6,600 ft, we’ll be able to see the black dragonfish a nightmarish creature that dwells in the deep and dark parts of the ocean.

- At 7,400 ft we’ll be saying goodbye to sperm whales  this is the deepest point they can dive. Frankly, They don't have any real business in such depths though.

-At 9,900 ft you'll be able to see the astonishing beauty of the deep-sea coral reefs.

-At 12,100 ft we reach the average depth of the world ocean. The Journey Of The real depths begins here, the general ocean floor has been passed, so now it's time to delve into the Abyss.

-12,467 ft, Yes, that's the same depth as of the final resting place of TITANIC.

-At 13,100 ft the pressure on the upper limit of the Abyss is like a whole regiment of elephants stomping on your head. Huh, Scary Right?

- At 15,000 ft, the monsters out of your worst nightmares pop up. Anglerfish for example. Or The black swallower, that can swallow prey that’s twice its size!

- At 18,900 ft you're as deep as where the deepest shipwreck ever found: SS Rio Grande in the south Atlantic in 1941. No Wonder it was only found 55 years later :p.

- At about 19,700 ft deep we're entering the deepest and darkest part of the ocean: we’re diving into the Mariana trench. Officially it begins from here.

- At 26,000 ft you'll find the deepest fish ever found i.e. the Snailfish. Its body is translucent, so you can see right through its skin.

- At 29,029 ft if you invert Mount Everest into the ocean it'll be completely submerged.

- Going lower and deeper, you won’t see any other kind of fish or vertebrate animal whatsoever — the pressure is just too much for such creatures. But there are shrimps and other invertebrates, not to mention microbes, that can dwell in the deepest part of the ocean and that part is CHALLENGER DEEP. Yes, you heard it right, We've Arrived at the very bottom of the Mariana Trench And its depth is 35,853~36,070 ft.

 

It Was Really A Fascinating Journey With All Of You And We Got To See Some Unrealistic Things Through All The Way Down Here. Few People Have Been Here And Hey, Congrats Now You're Also One Of Them. Though There Is A Lot To Discover About This Abyss Yet. But We're Not Gonna Stop, We'll Soon Find Out More About What Secrets The Depths Of The Ocean Holds.

But Hey!, Don't Go Deep Diving Alone Yet, Let Me Know In The Comment Section How Was Your Ride..!!

Facts About The Mariana Trench

The Mariana Trench, located in the Philippine Sea just off the coast of the Mariana Islands, is the deepest part of the ocean. Naturally, people don’t know much about it, but we are here to remedy that. Today we bring you Mariana trench facts that will blow your mind:

·         A Place of Extreme Temperatures... As you go further and further down into the depths of the ocean, the temperature gets steadily colder. It gets especially cold down in the dark and abysmal waters of the Mariana Trench. Temperatures there constantly hovers at just above freezing, somewhere between 1 degree Celsius to 4 degrees Celsius. But certain parts of the trench have temperatures on the opposite side of the scale. If you venture close to the hydrothermal vents that litter the Trench roughly a mile down. In a world where the water is one or two steps away from turning to ice, several vents shoot out water close to 450 degrees Celsius. Alternately known as “black smokers,” the water in these vents shoots out tons of minerals that help life in the area survive and thrive.

 

·         A High-Pressure Situation... The pressure exerted by water that deep is tremendous. According to scientists, down in the trench, you can experience up to 1100 times the pressure you would experience at sea level. To put that into perspective, if you can somehow get 100 elephants to stand on your head, you’d get an idea of how much pressure we are talking about here. The pressure is so high it increases the density of water to about five percent. That means if you take a one-liter bottle of water then dive down into the trench, by the time you get there the water in your bottle would be as dense as 9 and a half liters. Such extreme pressures should make it impossible for life to develop down there, but there are a few creatures that thrive under pressure and make the Mariana trench their home.

 

·         Clams... They Live There The intense water pressure down in the Trench makes it difficult for anything with a hard shell or bones to survive, hence the abundance of sea cucumbers and giant amoeba. If you stuck a turtle down there, it would almost certainly end up crushed by its shell. Of course, the recent discovery of shelled animals in the Trench, such as clams, should put a damper on this little stereotype. Discovered in early-2012, these clams largely reside near serpentine hydrothermal vents. The serpentine rock is rich with life-giving minerals such as hydrogen and methane, which allows life to form around it. Nobody yet knows for sure how the clams evolved their shells to be so sturdy under pressure and, unfortunately, they’re not talking. However, water pressure aside, these vents exude another gas—hydrogen sulfide—that is normally lethal to clams and other mollusks. Luckily for them, they’ve evolved the ability to bind the sulfide to harmless proteins, thereby nullifying its toxicity and allowing the deep-sea clam population to survive. 

 

·         A Little Bit of the Bubbly... Most of the hydrothermal vents mentioned previously spew nothing but regular, albeit extremely hot water that will singe your skin if you get anywhere near it. One vent, however, raises the game to an utterly ridiculous level, releasing not water, but pure liquid carbon dioxide. Outside of the Okinawa Trough near Taiwan, the Champagne Vent of the Mariana Trench is the only known underwater area where liquid carbon dioxide exists.

 

·         Pollution...a research expedition looked at the chemical makeup of crustacean scavengers collected from the range of 7,841–10,250 meters within the trench. Within these organisms, the researchers found extremely elevated concentrations of PCBs, a chemical toxin banned for its environmental harm in the 1970s, concentrated at all depths within the sediment of the trench. Further research has found that amphipods also ingest microplastics, with 100% of amphipods having at least one piece of synthetic material in their stomachs. In 2019, Victor Vescovo reported finding a plastic bag and candy wrappers at the bottom of the trench. That year, Scientific American also reported that carbon-14 from nuclear bomb testing has been found in the bodies of aquatic animals found in the trench.

 

·         A possible nuclear waste disposal site... Like other oceanic trenches, the Mariana Trench has been proposed as a site for nuclear waste disposal in 1972, in the hope that tectonic plate subduction occurring at the site might eventually push the nuclear waste deep into the Earth's mantle, the second layer of the Earth. However, ocean dumping of nuclear waste is prohibited by international law. Furthermore, plate subduction zones are associated with very large megathrust earthquakes, the effects of which are unpredictable for the safety of long-term disposal of nuclear wastes within the hadopelagic ecosystem.

 

·         Marianas Trench Marine National Monument... United States national monument at the trench. This National Monument protects 246,610 square kilometers (95,216 sq mi) of submerged lands and waters of the Mariana Archipelago. It includes some of the Mariana Trench, but not the deepest part, the Challenger Deep, which lies just outside the monument area.

 

 

Inhabitants Of Mariana Trench

The Mariana Trench Is Filled With Mysterious And Thrilled Species:

 

 

Clams... the giant clams are the members of the clam genus Tridacna that are the largest living bivalve mollusks. There are several species of "giant clams" in the genus Tridacna, which are often misidentified for Tridacna gigas, the most commonly intended species referred to as “the giant clam”. Tridacna gigas is one of the most endangered clam species.

 

Rat-Tail fish… These fish, also known as grenadiers, are one of the oldest fish families in the ocean! Strangely, they’re closely related to the cod, these fish are not only found in shallower waters but many habitats the deep waters of the Mariana Trench. They have a remarkable sense of smell and eat other small fish and crustaceans. They’re slow-moving fish and generally conserve their energy for the hunt. 

 

Deep-sea hatchet fish… No guesses as to why this deep-sea fish is called a hatchet fish and a number of these fellas have been spotted in the Mariana Trench. There are more than 40 different species of this fish, and they generally all grow to around 6-inches. They sport bioluminescent bodies and depending on how much light is filtering from above, they can alter the amount of light their bodies give off. The dimmer the light they give off, the less chance they have of producing a silhouette, making it more of a challenge for predators to spot them. 

 

Ooze… There’s no better word to describe what you would most likely be standing on if you were to ever make yourself to the very bottom of the Mariana Trench. Don’t think you’re going to be exposed to lovely sand like you find on the beach, but rather a disgusting ooze that has trickled through the depths and settled at the bottom. Everything from crushed shells to the corpses of plankton has made their way to the bottom. The sludge would be grayish-yellow, fine, and almost silky in texture. You have to wonder what it would smell like if it ever did make its way to the surface. 

 

Protists… We mentioned earlier that the deepest part of the Mariana Trench is called the Challenger Deep, and it’s just under 36,000-feet. There you will find a life-form called a protist. They’re not animals, but a rather single-celled organism that are believed to be some of the very first forms of life here on Earth. 

 

Frilled sharks… This crazy looking shark has said to be around for 80 million years, and little has changed in its appearance. The shark has 6 rows of frilly gills that can reach up to 6-feet long. The shark also has over 20 rows of sharp teeth that will do severe damage to anything that dares cross its path. Luckily, they prefer the bottom of the ocean, and although one has been caught on the odd occasion, they don’t survive to make it impossible to study them. 

 

 

Telescope octopus… These bizarre-looking deep-sea dwellers don’t flit across the ocean floor like regular octopi, but rather drift through the waters at around 6,500-feet. They also don’t swim horizontally, but suspend themselves vertically, possibly to distract predators. The telescope octopus is almost see-through, and there’s a delicate webbing between its tentacles, giving it a ghostly shape. And the cherry on the cake? Two protruding eyeballs providing the octopus with an ultra-wide peripheral vision so it can see predators and prey and helping it make its way through the murky, dark depths. 

 

ORCA...The killer whale, or orca (Orcinus orca), is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. Orca has a diverse diet, although individual populations often specialize in particular types of prey. They are Known As Apex Predators, as no animal preys on them. 

 

Monothalamea...It is a grouping of foraminiferans, traditionally consisting of all foraminifera with single-chambered tests. Recent work has shown that the grouping is paraphyletic, and as such does not constitute a natural group; nonetheless, the name continues to be used by foraminifera workers out of convenience.

 

Deep-Water Corals... The habitat of deep-water corals, also known as cold-water corals, extends to deeper, darker parts of the oceans than tropical corals, ranging from near the surface to the abyss, beyond 2,000 meters (6,600 ft) where water temperatures may be as cold as 4 °C (39 °F). Deep-water corals belong to the Phylum Cnidaria and are most often stony corals, but also include black and horny corals and soft corals including the Gorgonians (sea fans). Like tropical corals, they provide habitat to other species, but deep-water corals do not require zooxanthellae to survive.

 

Angler Fish... The anglerfish is a fish of the teleost order Lophiiformes. It is a bony fish named for its characteristic mode of predation, in which a fleshy growth from the fish's head (the esca or illicium) acts as a lure for other fish.

 

“Could life exist in the greatest depths of the ocean? It could!”