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8 Surprising Facts About the Deepest Part of the Ocean

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NOAA

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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iStock // Ekaterina Minaeva
technology
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Scientists Think They Know How Whales Got So Big
May 24, 2017
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It can be difficult to understand how enormous the blue whale—the largest animal to ever exist—really is. The mammal can measure up to 105 feet long, have a tongue that can weigh as much as an elephant, and have a massive, golf cart–sized heart powering a 200-ton frame. But while the blue whale might currently be the Andre the Giant of the sea, it wasn’t always so imposing.

For the majority of the 30 million years that baleen whales (the blue whale is one) have occupied the Earth, the mammals usually topped off at roughly 30 feet in length. It wasn’t until about 3 million years ago that the clade of whales experienced an evolutionary growth spurt, tripling in size. And scientists haven’t had any concrete idea why, Wired reports.

A study published in the journal Proceedings of the Royal Society B might help change that. Researchers examined fossil records and studied phylogenetic models (evolutionary relationships) among baleen whales, and found some evidence that climate change may have been the catalyst for turning the large animals into behemoths.

As the ice ages wore on and oceans were receiving nutrient-rich runoff, the whales encountered an increasing number of krill—the small, shrimp-like creatures that provided a food source—resulting from upwelling waters. The more they ate, the more they grew, and their bodies adapted over time. Their mouths grew larger and their fat stores increased, helping them to fuel longer migrations to additional food-enriched areas. Today blue whales eat up to four tons of krill every day.

If climate change set the ancestors of the blue whale on the path to its enormous size today, the study invites the question of what it might do to them in the future. Changes in ocean currents or temperature could alter the amount of available nutrients to whales, cutting off their food supply. With demand for whale oil in the 1900s having already dented their numbers, scientists are hoping that further shifts in their oceanic ecosystem won’t relegate them to history.

[h/t Wired]

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