By BC Cook
For Variety
THE Mariana Trench has received a lot of publicity lately. It is in our backyard, so we all know something about it. If you have not had a chance to learn about the Mariana Trench, enjoy these facts.
Twenty-two ocean trenches have been found worldwide, 19 of them in the Pacific but none deeper than ours. Since we are the closest to the trench, it is named after the Mariana islands. At over 36,000 feet (seven miles) it is the deepest part of the ocean, so deep that if you sank Mount Everest into it there would still be a mile of water above its peak. It runs over 1500 miles from one end to the other, about the distance from Saipan to Manila, and about 43 miles wide.
No one knew the trench was there until about seventy years ago, when the British science vessel Challenger II, led by Jacques Piccard, found it. They named the deepest point Challenger Deep, after the ship.
Only a handful people have ever been to the bottom and back. In 1960 two men did it in a specially-built submarine named Trieste, and a few years ago James Cameron did it alone in his Deepsea Challenger. It is not the kind of place humans would spend a lot of time. At that depth the pressure is over eight tons per square inch. Picture four Toyotas parked on your wristwatch, or three hundred of them parked on your head.
As for light, suppose you were the same height as the Mariana Trench, so the top of your head is the ocean surface and you stood in the bottom of the trench. It would be pitch-black before you got down to your eyebrows. Light penetrates less than two percent of the depth of the trench. So before heading to the bottom make sure you have extra batteries for your flashlights.
The bottom of the trench is all about extremes. In addition to the pressure and inky darkness, water at that depth is very cold, below freezing actually, but the salt in the water keeps it liquid. There is extreme heat coming from the volcanic vents at the bottom so in some places the water boils briefly before turning ice-cold. Other than the vents, the rest of the bottom of the trench is covered with a thick sludge that scientists call “ooze,” made up of dead fish and animals, trash, decaying plants, and shells.
Surprisingly, there is a lot of life at the bottom. Thousands of species are specially suited to live in this cold, dark, high-pressure world. There are giant shrimp the size of dogs, fish with huge teeth and a light-producing lure. And everyone has heard of the giant squid, though not as giant as Hollywood would have us believe. Bacteria and other microorganisms thrive.
Challenger Deep is the closest we can get to the earth’s core so perhaps we can increase our knowledge of plate tectonics, volcanoes, or magnetism. The possibilities are endless. Mariana Trench is another important part of our Pacific heritage, as unique as the Easter Island statues or the ruins of Nan Madol on Pohnpei. It is another reason why living here is so special.
Dr. BC Cook taught history for 30 years and is a director and Pacific historian at Sealark Exploration (sealarkexploration.org). He currently lives in Hawaii.
