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8 Surprising Facts About the Deepest Part of the Ocean

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The deepest part of our oceans, the region from below 20,000 feet to the very bottom of the deepest sea trench, is known as the hadal zone. It's named after Hades, the underworld of Greek mythology (and its god). The majority of the hadal zone is made up of plunging trenches formed by shifting tectonic plates. To date, some 46 hadal habitats have been identified—about 41 percent of the total depth range of the entire ocean, and yet less than one quarter of 1 percent of the entire ocean. Scientists still know very little about this mysterious and difficult to study region, but what we have learned is astounding. 

1. MORE PEOPLE HAVE BEEN TO THE MOON THAN HAVE EXPLORED THE HADAL DEEP.

To give some perspective, Mount Everest would fit inside the deepest sea trench on Earth, the Mariana Trench, with a few miles to spare. This helps explain why it has been so rarely explored—only three people have ever made it to the bottom of the Mariana trench: two scientists aboard the Trieste in 1960, and the film director James Cameron in 2012.

The trenches of the hadal deep are so remote that getting equipment or people to such depths is extremely difficult. This is compounded by the fact that the underwater pressure at that depth—approximately 8 tons per square inch, roughly that of 100 elephants standing on your head—causes ordinary instruments to implode.

Scientists venturing so far down require special equipment that can withstand the immense pressure, but even those can be unreliable. In 2014, the remote unmanned sub Nereus became the latest in a long line of research probes to be lost during a mission. Nereus was built by Woods Hole Oceanographic Institution (WHOI) and had completed several ground-breaking missions into the hadal zone, including in 2009 reaching the bottom of the Mariana Trench. But during its last mission, into the Kermadec Trench just off New Zealand, the sub imploded and broke apart, likely because of the intense water pressure. You can see some footage of the Nereus sampling the seafloor of the Mariana Trench during its 2009 expedition. 

2. THE EXTRAORDINARY DEPTHS ARE MEASURED USING TNT.

To measure the very deepest parts of the ocean, scientists use bomb sounding, a technique where TNT is thrown into the trenches and the echo is recorded from a boat, allowing scientists to estimate the depth. While scientists question the sensitivity of the method, even the rough results are impressive: So far, in addition to the Mariana Trench, four other trenches—the Kermadec, Kuril-Kamchatka, Philippine, and Tonga, all in the Western Pacific Ocean—have been identified as deeper than 10,000 meters (32,808 feet).

3. JACQUES COUSTEAU WAS THE FIRST TO PHOTOGRAPH THE HADAL ZONE.

The first expedition to take samples from the hadal zone was the trail-blazing HMS Challenger Expedition, working from 1872 to 1876. Scientists on board managed to extract samples from 26,246 feet under the ocean, but at that time were not able to confirm if the animal remains they found were actually living at that depth or were simply the remains of marine creatures from higher up in the ocean which had sunk to that depth after death. It was not until 1948 that a Swedish research vessel, Albatross, was able to collect samples from 25,000 feet, which proved that creatures existed at greater depths than 20,000 feet, and thus that the hadal zone was inhabited.

But it wasn’t until 1956 that Jacques Cousteau took the first photograph of the hadal zone. Cousteau submerged his camera to the sea-floor of the Romanche Trench in the Atlantic Ocean, some 24,500 feet down, providing the first glimpse of this previously unseen part of the ocean.

4. WE’VE JUST CONFIRMED THE DEEPEST SIGHTING OF A LIVE FISH.

Studying the creatures that survive in the hadal zone can be very challenging. Prior to 2008, most species were described from just one sample, often in a poor state. (One scientist described most hadal samples as “shrivelled specimens in museums.”) In 2008, in a huge leap toward understanding deep sea creatures, the first images of live organisms from the hadal zone were recorded. The Japanese research vessel Hakuho-Maru deployed a freefall baited lander in the Japan Trench in the Pacific Ocean, becoming the first scientists to produce images of live hadal creatures in situ. The camera caught pictures of hadal snailfish (Pseudoliparis amblystomopsis), which are thought to be the most prevalent species at hadal depths. The images surprisingly showed swarms of active fish feeding on tiny shrimp—overturning ideas that fish at this depth would be solitary, sluggish creatures barely eking out an existence. A 2016 paper went on to identify live snailfish at a depth of 26,722 feet—the deepest confirmed sighting of a live specimen.

5. BUT WE DON’T KNOW HOW MUCH DEEPER FISH MIGHT SURVIVE.

Recent expeditions such as the HADES project in the Pacific suggest that fish are not found below 27,560 feet. But the hadal zone extends to 36,000 feet. Whitman College marine biologist Paul Yancey hypothesizes that fish reach a limit around 27,500 feet because proteins at such great depths cannot build properly. To counteract this, deep-sea fish have developed an organic molecule known as trimethylamine oxide, or TMAO (this molecule also gives fish their “fishy” smell), which helps proteins work at high pressure. Shallow water fish have fairly low levels of TMAO, while deep sea fish have increasingly high levels. Yancey proposes that the amount of TMAO required to counteract the huge pressure below 27,560 feet would be so great that water would begin to flow uncontrollably through their bodies, killing the fish.

Below 27,560 feet however, other types of creatures do exist, such as shrimp-like hadal amphipods. These creatures scavenge on the waste and dead bodies from sea creatures which float down from above, amazingly thriving at great depths.

6. TONS OF TOXIC WASTE WAS DUMPED INTO THE HADAL ZONE.

In the 1970s, tons of toxic pharmaceutical waste—the equivalent of 880 Boeing 747s—was dumped into the Puerto Rico Trench. At the time Puerto Rico was a large producer of pharmaceuticals, and the dumping was allowed as a temporary measure while a new wastewater treatment site was built. Inevitably, delays meant that dumping continued at the site into the 1980s. Samples taken from the dump site indicated that ecosystems were seriously damaged by the pollutants, with a 1981 study revealing “demonstrable changes in the marine microbial community in the region used for waste disposal.”

7. THE STUDY OF HADAL DEEP HELPS OUR UNDERSTANDING OF HOW LIFE MIGHT SURVIVE IN SPACE.

Creatures that thrive in extreme environments such as the hadal zone are called extremophiles. These creatures can withstand very low temperatures, high pressures, and can survive with little or no oxygen. Studying these extraordinary animals can lend great insights to scientists, indicating how life might persist in space where no oxygen is present. Microorganisms such as Pyrococcus CH1 have been found in deep sea vents, gifting scientists with an idea of the type of life that could exist on planets such as Jupiter’s moon, Europa.

8. SUPERGIANTS EXIST IN THE HADAL ZONE.

One of the most excitingly named creatures found in the hadal zone is the enigmatic supergiant, also known as Alicella gigantea. This amphipod is at least 20 times the size of its shallower-dwelling cousins. This makes them sound super exciting, until you realize they’re still miniscule creatures related to the humble sand hopper—a tiny beast often found popping out of the seaweed at the beach at high speed. The largest specimen of supergiant ever found was a 13.4-inch-long female, found in a trench in the Pacific Ocean.

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Space
Watch NASA Test Its New Supersonic Parachute at 1300 Miles Per Hour
NASA/JPL, YouTube
NASA/JPL, YouTube

NASA’s latest Mars rover is headed for the Red Planet in 2020, and the space agency is working hard to make sure its $2.1 billion project will land safely. When the Mars 2020 rover enters the Martian atmosphere, it’ll be assisted by a brand-new, advanced parachute system that’s a joy to watch in action, as a new video of its first test flight shows.

Spotted by Gizmodo, the video was taken in early October at NASA’s Wallops Flight Facility in Virginia. Narrated by the technical lead from the test flight, the Jet Propulsion Laboratory’s Ian Clark, the two-and-a-half-minute video shows the 30-mile-high launch of a rocket carrying the new, supersonic parachute.

The 100-pound, Kevlar-based parachute unfurls at almost 100 miles an hour, and when it is entirely deployed, it’s moving at almost 1300 miles an hour—1.8 times the speed of sound. To be able to slow the spacecraft down as it enters the Martian atmosphere, the parachute generates almost 35,000 pounds of drag force.

For those of us watching at home, the video is just eye candy. But NASA researchers use it to monitor how the fabric moves, how the parachute unfurls and inflates, and how uniform the motion is, checking to see that everything is in order. The test flight ends with the payload crashing into the ocean, but it won’t be the last time the parachute takes flight in the coming months. More test flights are scheduled to ensure that everything is ready for liftoff in 2020.

[h/t Gizmodo]

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Christopher Furlong/Getty Images
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architecture
German Nonprofit Gives $1.1 Million to Restore World’s First Iron Bridge in England
Christopher Furlong/Getty Images
Christopher Furlong/Getty Images

The UK’s Iron Bridge is more than just a pretty landmark. Built in 1779, it was the world’s first metal bridge, a major milestone in engineering history. Like many aging pieces of infrastructure, though, it’s in dire need of repair—and the funds to shore it up are coming from an unexpected place. According to The Times, a German foundation has pledged to pay for the conservation project as a way to improve relations between England and Germany in the wake of Brexit.

Based in Hamburg, the Hermann Reemtsma Foundation normally funds cultural projects in Germany, but decided to work with the UK’s charitable trust English Heritage to save the Industrial Revolution landmark as a way to reinforce the cultural bond between the two countries. The foundation has pledged more than $1.16 million to the bridge's renovation effort, which will cost an estimated $4.7 million in total. Now, the UK charity only has to raise another $32,800 to fully fund the work.

The Iron Bridge was cast and built by Abraham Darby III, whose grandfather became the first mass-producer of cast iron in the UK in the early 1700s, kickstarting England's Industrial Revolution. It was the world’s first cast iron, single-span arch bridge, weighing more than 400 tons. In 1934, it was declared a historic monument and closed to traffic, and the Ironbridge Gorge was named a UNESCO World Heritage Site in 1986.

“The Iron Bridge is one of the most important—if not the most important—bridges ever built,” English Heritage CEO Kate Mavor told the press.

The techniques used to erect the Iron Bridge were later adopted throughout Europe, including in Germany, leading the Hermann Reemtsma Foundation to call it “a potent reminder of our continent's common cultural roots and values.”

The already-underway repair project includes replacing elements of the bridge, cleaning and repairing others, and painting the entire structure. Since it sits above a fast-flowing river where erecting scaffolding is difficult, the project is especially complex. It’s scheduled to be completed in 2018.

[h/t The Times]

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