The deepest spot on Earth is a surprisingly noisy place, scientists from Oregon discovered when they lowered a hydrophone almost seven miles below the ocean surface into the Challenger Deep. Listen to what they found. 
 
 The deepest spot on Earth is a surprisingly noisy place, scientists from Oregon discovered when they lowered a hydrophone almost seven miles below the ocean surface into the Challenger Deep. 
 
 Left in place for several months, the device recorded the booming cries of whales, the rumble of ships passing overhead and crescendos from earthquakes deep in the planet’s crust. 
 
 “This should be one of the quietest places in the world, but it was a lot noisier than we expected,” said Oregon-based oceanographer Robert Dziak, who led the project for the National Oceanic and Atmospheric Administration (NOAA). “There really is almost constant sound from natural and man-made sources.” 
 
 
 
 Only a handful of vessels have ever penetrated the Challenger Deep, the deepest canyon in the fabled Mariana Trench near Micronesia. If Mount Everest were tucked into the nearly 36,000-foot chasm, it would still be covered by more than a mile of water. 
 
 The most recent human visitor was filmmaker James Cameron, who descended to the bottom alone in 2012 and spent two hours there in his custom-built submarine. 
 
 A few remotely operated vehicles and instruments have been deployed in the Mariana Trench, but Dziak said the recent recordings might be the first ever captured at such great depths. 
 
 “It’s not an easy thing to do to get an instrument package to the seafloor, recover it from that depth and have it survive,” he said. 
 
 The 20-inch-long hydrophone was designed for the job by Oregon State University engineer Haru Matsumoto and Chris Meinig, of NOAA’s Pacific Marine Environmental Laboratory in Seattle. It was crafted from titanium nearly an inch thick to withstand pressures of 16,000 pounds per square inch — a force that could crush a car like paper crumpled in a fist. 
 
 “We had never put a hydrophone deeper than a mile or so below the surface,” Matsumoto said. 
 
 To avoid rapid pressure change, the device was lowered to the seafloor over a six-hour period. An anchor system also developed at the marine laboratory held the instrument in place, suspended about 20 feet above the soft bottom. 
 
 The U.S. Coast Guard volunteered the Guam-based cutter Sequoia for the deployment mission in July 2015. The scientists returned to fetch the recorder in November, sending an acoustic signal that triggered a release mechanism and allowed the device to rise slowly to the surface. 
 
 The research is part of a broader effort to monitor increasing levels of man-made noise in the world’s oceans — and their effect on marine life. “Our goal is to make comprehensive sound maps of the ocean,” Dziak explained. 
 
 The team targeted the Challenger Deep for baseline recordings, because they expected the slot-shaped canyon to be largely insulated from the global cacophony. 
 
 So they were surprised as they began analyzing the recordings. 
 
 The Mariana Trench is a seismically active subduction zone, where one tectonic plate dives under another, so earthquakes were a regular occurrence. Captured by the hydrophone, the rumble of the quakes builds in intensity like an approaching train. 
 
 Ship noise is higher-pitched and more rhythmic. The nearby island of Guam is on a major transoceanic route, so vessel traffic was a nearly constant source of noise in the environment, the researchers found. 
 
 The level of conversation between marine mammals picked up by the hydrophones was unexpected, Dziak said. Few whales dive much deeper than about a mile — yet their voices traveled clearly to the bottom of the trench. 
 
 A baleen whale of unknown type captured on the recordings seems to mimic a fog horn, while the deep-pitched calls of a toothed whale or dolphin sound like muffled thunder. 
 
 The hydrophone also recorded the roar of a typhoon, churning the surface 200 miles north of the trench. “There was a huge amount of energy, high winds, big waves, that made the whole basin noisy,” Dziak said. 
 
 The project clearly shows that man-made noise is present even in some of the most remote corners of the planet. Next, the researchers plan to deploy hydrophones under the Arctic ice cap, to measure sound levels there before melting opens the area to more ship traffic. 
 
 And they hope to return to the Challenger Deep in 2017, this time deploying a camera along with the hydrophones. ||||| Listening to the deep 
 
 Posted by PA1 David J. Schuhlein, Thursday, February 12, 2015 
 
 Written by Petty Officer 2nd Class Tara Molle 
 
 We know more about the surface of the Moon and Mars than we do about the ocean’s seafloor. With water encompassing 63.78 million square miles, the oceans cover 70 percent of the Earth’s surface, with the world’s largest body of water, the Pacific Ocean, covering roughly one third. The Pacific also boasts the deepest trenches, specifically Challenger Deep in the Mariana Trench near the Federated States of Micronesia. Given Challenger Deep’s inhospitable environment, no one has attempted to extensively record ambient sound at its full depth. That is, until now. 
 
 Housed in a cylindrical titanium pressure case, National Oceanic and Atmospheric Administration scientists designed a hydrophone capable of withstanding the 16,142 pounds of pressure per square inch in Challenger Deep. The ceramic pressure sensor is specifically designed for deep-ocean work, and houses the electronics, disk storage, pre-amplifier and battery case for a special mission. 
 
 Engineers at NOAA’s Pacific Marine Environmental Laboratory partnered with the Coast Guard to deploy the hydrophone into Challenger Deep using the Coast Guard’s unique capability of navigating to an exact position. 
 
 “Our plan is to make a baseline record of sound levels at Challenger Deep to investigate the levels of anthropogenic sound at these depths as well as gauge the contribution from natural sources such as submarine earthquakes and volcanoes,” said Dr. Robert Dziak, a research oceanographer with NOAA and a chief scientist of the project. “Hopefully we’ll also record sounds generated by unique animal life that exist at these depths,” 
 
 NOAA utilized the Coast Guard Cutter Sequoia, a 225-foot Juniper-class buoy tender home-ported in Apra Harbor, Guam, as a platform to deploy the hydrophone Jan. 17, 2015, 204 miles southwest of Guam. 
 
 “The joint mission was a great success and we are pleased to have been able to assist NOAA personnel in the deployment of their scientific equipment in such a remote location,” said Lt. Cmdr. Jessica Worst. “The operation was a perfect example of our 225-foot bouy tender’s versatility and multi-mission capability. While our positioning system and crane are normally used for servicing aids to navigation closer to the coast, the abilities of our equipment and crew easily translated over to this deep ocean scientific deployment.” 
 
 The ocean is full of ambient noise made by various things. Currents, animals and man-made noise from ship traffic generate sound waves in the deep blue sea, Dziak noted. He added that as with any scientific research, there are a lot of unknowns. 
 
 “The Challenger Deep should be one of the quietest places in the world’s oceans, with very little contribution from man-made noise, but we won’t know for sure until we make these measurements,” said Dziak. “This project also represents true exploration and we don’t know exactly what we’ll record. We don’t fully know what physical or biological processing are occurring down at these depths or what type of sounds the animal life there may be producing.” 
 
 Man-made noise heavily impacts the ocean and has also increased over the years. The hydrophone will be used to listen and see if man-made noise will make it into the seemingly endless depth of approximately seven miles. In fact, if you placed Mount Everest at the trench’s seafloor, you’d still have over a mile of water left above its peak. 
 
 The daunting task at hand required the hydrophone to free-fall approximately six hours one-way to the seafloor. The hydrophone cylinders are attached to several miles of mooring line and floats. It will be left at the seabed for three to four weeks to capture ambient sound needed to conduct the research. Once it’s retrieved, NOAA will release the raw, unprocessed sound for public download and release short recordings of interesting sounds on their website to highlight the project. 
 
 “We are cautiously optimistic that recovery will go smoothly and that the hydrophone will have recorded data,” said Dziak. “If we successfully record sound data and become one of the first, if not the first to make recordings at Challenger Deep, then our excitement will be off the charts!” 
 
 We are now left to our own imaginations to the sights and now sounds of what lies within Challenger Deep. What could we hear? Will the thousands of life forms inhabiting the oceans and commercial ships transiting the seas daily produce sounds to that depth? Is the Megalodon lurking below waiting to be rediscovered, or is the Challenger Deep truly the quietest place on Earth? Only time will tell. 
 
 For more information visit the NOAA PMEL Acoustics. 
 
 Comments 
 
 comments 
 
 Tags: 14th coast guard district, Apra Harbor, Challenger Deep, Coast Guard, coast guard compass, coast guard cutter sequoia, coast guard guam, coast guard hawaii, guam, National Oceanic and Atmospheric Administration, scientists, tara molle ||||| It turns out the ocean is one noisy, riotous place, teeming with the sound of seismic temblors, whale songs and ship propellers — even at the deepest ocean trench. 
 
 Researchers at the National Oceanic and Atmospheric Administration (NOAA) sent an underwater microphone nearly 36,000 feet (10,972 meters) below the water's surface into the Challenger Deep trough in the Mariana Trench, the deepest spot in the ocean. [Listen to Sounds from the Deepest Spot in the Ocean] 
 
 "You would think that the deepest part of the ocean would be one of the quietest places on Earth," Robert Dziak, a research oceanographer and chief project scientist with NOAA, said in a statement. "Yet there is almost constant noise. The ambient sound field is dominated by the sound of earthquakes, both near and far, as well as distinct moans of baleen whales and the clamor of a category 4 typhoon that just happened to pass overhead." 
 
 Commercial freight ships, submarines and underwater construction projects have all added to the noisy din found under the waves. In fact, the ocean may be about 10 times noisier today than it was 50 years ago, said Ocean Conservation Research, an organization that studies human-caused noise in the world's oceans. 
 
 Researchers at NOAA said they wanted to understand whether all that human din was actually causing noise levels in the deep ocean to increase, and if so, how that noise affected the migration, communication and feeding patterns of sonar-reliant creatures such as dolphins and whales. To do so, the scientists said they wanted to establish a baseline noise level for the deep ocean, which could help reveal if noise levels are likely to rise in the coming decades. 
 
 But getting the underwater microphone, or hydrophone, nearly 7 miles (11 kilometers) underwater was no trivial matter. The pressure at the bottom of the Mariana Trench is more than 1,000 times the atmospheric pressure at sea level. [In Photos: James Cameron's Epic Dive to Challenger Deep] 
 
 "The pressure at that depth is incredible," Haru Matsumoto, an Oregon State University ocean engineer who worked on the project, said in the statement. "We had to drop the hydrophone mooring down through the water column at no more than 5 m [16 feet] per second to be sure the hydrophone, which is made of ceramic, would survive the rapid pressure change." 
 
 In July 2015, the team released the hydrophone from a U.S. Coast Guard ship docked off the coast of Guam and anchored the device to the bottom of the Challenger Deep trough. They then recorded 23 days of ocean noise, until the flash drive on the device was full. 
 
 When the team hauled up the hydrophone, they discovered there was a constant thrum of noise lurking beneath the waves. Whale songs, ship propellers, seismic waves from a 5.0-magnitude earthquake in the ocean crust off Guam and even overhead typhoons sent sound waves reverberating into the deepest part of the ocean. 
 
 The team said it plans to return in 2017 to see how the noise of the deep ocean has changed. 
 
 Follow Tia Ghose on Twitter and Google+. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science. ||||| Deep rumbles, unearthly moans, high pitched screeching: these are but a few elements of the alien soundscape researchers have now recorded for the first time at Challenger Deep, the deepest known valley on the seafloor. 
 
 One might expect Challenger Deep—which sits at the bottom of the Mariana trench some 36,000 feet beneath the ocean surface—to be a quiet place. But in reality, we know very little about what life is like down there: as with most places where the sun never shines, the Mariana trench is shrouded in mystery. 
 
 Advertisement 
 
 “Light does not propagate underwater very far,” oceanographer Bob Dziak of the National Oceanic and Atmospheric Administration (NOAA) told Gizmodo. “But sound waves travel long distances through the Earth’s oceans. Acoustics is really the best way to get a good picture of deep ocean environments.” 
 
 The propellor from a ship passing above makes quite a ruckus at Challenger Deep 
 
 Dziak would know. He’s the guy who led the recent effort to capture audio recordings from Challenger Deep. First, Dizak and his team had to design and build an instrument that could withstand the crushing 16,000 pounds-per-square-inch worth of pressure felt seven miles beneath the surface. Next, they developed a mooring system that would lower their audio gear—a titanium-encased hydrophone—at a slow, controlled speed, so that it could acclimate to the dramatic pressure buildup during its journey. 
 
 Advertisement 
 
 And after successfully planting a hydrophone in Challenger Deep, and making recordings for 23 straight days, Dziak’s team had to wait until November for the weather and ship traffic to clear so they could haul it back up. It was a major effort, but now, we’ve got the first soundbites from the deepest spot on the Earth’s surface to show for it. 
 
 They’re as haunting and otherworldly as you might imagine. 
 
 Advertisement 
 
 A baleen whale call recorded at Challenger Deep 
 
 Examples of odontocete (toothed whale or dolphin) and baleen whale calls 
 
 Challenger Deep, it turns out, is an echo chamber for a cacophony of noises produced by everything from ships to baleen whales to Earth itself. In one recording, the researchers even identified the ominous rustling of a category four typhoon whipping across the surface miles above. “I was surprised by just how cleanly we can record whales, ships, and all sorts of activity taking place at the surface,” Dziak noted. 
 
 Advertisement 
 
 A magnitude 5 earthquake rumbles near Challenger Deep on July 16th 
 
 Advertisement 
 
 A baleen whale vocalizing just before and after the magnitude 5 quake 
 
 Dziak hopes to return to Challenger Deep to capture more audio in the future. He’d also like to use his high-pressure hydrophone to explore other uncharted waters, including remote areas of the deep Arctic Ocean that are now starting to open up to ships as the ice caps retreat. 
 
 
 
 “It is akin to sending a deep-space probe to the outer solar system,” Dziak said. “We’re sending out a deep-ocean probe to the unknown reaches of inner space.” 
 
 
 
 Advertisement 
 
 Follow the author @themadstone ||||| For three weeks, a titanium-encased hydrophone recorded ambient noise from the ocean floor at a depth of more than 36,000 feet, or 7 miles, in the Challenger Deep trough in the Mariana Trench near Micronesia. Researchers from NOAA, Oregon State University, and the U.S. Coast Guard were surprised by how much they heard. 
 
 “You would think that the deepest part of the ocean would be one of the quietest places on Earth,” said Robert Dziak, a NOAA research oceanographer and chief project scientist. “Yet there is almost constant noise. The ambient sound field is dominated by the sound of earthquakes, both near and far, as well as distinct moans of baleen whales, and the clamor of a category 4 typhoon that just happened to pass overhead.” 
 
 The hydrophone also picked up sound from ship propellers. Challenger Deep is close to Guam, a regional hub for container shipping with China and the Philippines. 
 
 The project, which was funded by the NOAA’s Office of Ocean Exploration and Research, was designed to establish a baseline for ambient noise in the deepest part of the Pacific Ocean. Human-created noise has increased steadily in recent decades and getting these first recordings allows scientists in the future to determine if the noise levels are growing and how this might affect marine animals that use sound to communicate, navigate and feed, such as whales, dolphins and fish. 
 
 Getting these first recordings wasn’t easy in an underwater trough deep enough to hold Mount Everest. 
 
 “The pressure at that depth is incredible,” said Haru Matsumoto, an Oregon State ocean engineer who worked with NOAA engineer Chris Meinig to adapt the hydrophone. “We had to drop the hydrophone mooring down through the water column at no more than five meters per second to be sure the hydrophone, which is made of ceramic, would survive the rapid pressure change.” 
 
 While atmospheric pressure in the average home or office is 14.7 pounds per square inch (PSI), it is more than 16,000 PSI at the bottom of the Mariana Trench. 
 
 Researchers deployed the hydrophone from the Guam-based U.S. Coast Guard Cutter Sequoia in July 2015. The device recorded sound continuously over 23 days, completely filling the flash drive. However, scientists had to wait until November to retrieve the hydrophone due to ships’ schedules and persistent typhoons. The device remained anchored to the seafloor until scientists returned. 
 
 Another OSU co-investigator on the project, Joe Haxel, will lead a planned return to Challenger Deep in early 2017, where the researchers will deploy the hydrophone for a longer period of time and attach a deep-ocean camera. 
 
 Dziak, Matsumoto, and Haxel all work for NOAA’s Pacific Marine Environmental Laboratory in the Acoustics Program located at OSU’s Hatfield Marine Science Centeroffsite link. Haxel and Matsumoto are also affiliated with the Cooperative Institute for Marine Resources Studies in Newport, Oregon. The acoustic project in Challenger Deep is one of a number of projects in which the U.S. Coast Guard partners with NOAA to support scientific research. 
 
 NOAA’s mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Join us on Facebook, Twitter, Instagram and our other social media channels. ||||| A hydrophone, or underwater microphone, spent almost a month in the deepest part of the ocean and recorded some surprising sounds. 
 
 No more watching videos at work: Facebook will now default to audio 
 
 In this undated photo provided by arthowardphotography.com, a deep sea coral reef is seen from a four-man submersible more than 1,000 feet down in the Atlantic Ocean about 50 miles off the southeastern coast of the United States. 
 
 Scientists expected seven miles under the ocean’s surface to be very quiet. 
 
 But a team of researchers from the National Oceanic Atmospheric Administration (NOAA), the US Coast Guard, and Oregon State University (OSU) dropped an underwater microphone 36,200 feet to the bottom of the Challenger Deep, the deepest part of the ocean, and were surprised by their findings. 
 
 “You would think that the deepest part of the ocean would be one of the quietest places on Earth,” Robert Dziak, a NOAA research oceanographer and chief scientist on the project, tells Oregon State University. “Yet there really is almost constant noise from both natural and man-made sources … Sound doesn’t get as weak as you think it does even that far from the source.” 
 
 The Challenger Deep depression is at the southern end of the underwater Mariana Trench, southwest of Guam. Compared to the average ocean depth of 2.3 miles, little is known about the Challenger’s mysterious setting seven miles beneath the ocean surface. Even if Mount Everest, Earth’s tallest mountain at about 5.5 miles above sea level, were relocated to the bottom of the Challenger Deep, more than a mile of water would still cover its peak. 
 
 Previous studies have suggested that not much lives in these dark depths. Apart from foot-long shrimp-like crustaceans, sea cucumbers and giant amoebas, the area's lack of light and intense pressure makes the area desolate. 
 
 But within 23 days, the device's storage was filled with noise. So if the bottom of the world is pretty much empty, why is it so loud? 
 
 “There was a huge amount of energy, high winds, big waves, that made the whole basin noisy,” Dziak tells the Seattle Times. While the hydrophone was underwater, it picked up sounds from a category 4 typhoon overhead and earthquake rumbles below. 
 
 Local whales don’t swim more than a mile below the ocean’s surface, but the calls of baleen and toothed whales also carried down to the bottom of the trench. 
 
 But the prevalence of human noise may have been the most surprising. 
 
 “The project clearly shows that man-made noise is present even in some of the most remote corners of the planet,” explains the Seattle Times. “The nearby island of Guam is on a major transoceanic route, so vessel traffic was a near constant source of noise in the environment, the researchers found.” With transocean traffic increasing, underwater noise pollution is becoming more and more prevalent – and the Challenger Deep proves to be no exception. 
 
 “Underwater sounds are a particularly important area of study, as scientists have learned in recent years that too much man-made noise in the ocean – from ship traffic, oil and gas exploration, scientific research, and military sonar – can have harmful effects on its inhabitants,” The Christian Science Monitor’s Lonnie Shekhtman explained last week. 
 
 The team of scientists are now planning for another venture in 2017, when a camera will hopefully accompany the hydrophone. But getting to the deepest part of the world isn’t easy. 
 
 “We had never put a hydrophone deeper than a mile or so below the surface, so putting an instrument down some seven miles into the ocean was daunting,” Haru Matsumoto, an Oregon State ocean engineer who helped develop the hydrophone, tells OSU. 
 
 The pressure is hard for us to imagine, says Matsumoto. At 16,000 pounds per square inch, the pressure at the bottom of Mariana Trench is about 1,088 times that which humans experience on a day-to-day basis. 
 
 “We had to drop the hydrophone mooring down through the water column at no more than about five meters per second,” says Matsumoto, which took more than six hours. The team of researchers feared a fast drop would break the hydrophone. “It is akin to sending a deep-space probe to the outer solar system. We’re sending out a deep-ocean probe to the unknown reaches of inner space.”
– "You would think that the deepest part of the ocean would be one of the quietest places on Earth," says NOAA research oceanographer Robert Dziak, but it's not so. NOAA, with the help of partner scientists, recently listened in on the deepest point of the ocean and found what a press release calls a "cacophony of sounds." Some of those sounds were natural (the moans of baleen whales, a typhoon that passed overhead, earthquakes, and, per the Coast Guard, underwater volcanoes) while others were created by humans (ship propellers and, per LiveScience, submarines and "underwater construction projects"). The agency wanted to determine how noisy it is down there in order to establish a baseline, so that, as human-created noise continues to increase, future scientists can see if the noise level at the bottom of the ocean is also increasing—and, if so, what effect that increase might be having on marine animals that use sound to communicate, find their way around, and find food. In order to monitor the ambient noise at the bottom of the ocean (which you can listen to here), a ceramic hydrophone encased in titanium was dropped to the ocean floor—in the Challenger Deep, an underground trough in the Mariana Trench near Micronesia that is "deep enough to hold Mount Everest" at more than 7 miles—where it recorded for 23 days in July. Scientists know human-created noise has been growing for decades now. Even so, the press release says they were "surprised by how much they heard," and Dziak tells the Seattle Times, "This should be one of the quietest places in the world, but it was a lot noisier than we expected." As it turns out, he tells the Christian Science Monitor now, "Sound doesn’t get as weak as you think it does even that far from the source." "I was surprised by just how cleanly we can record whales, ships, and all sorts of activity taking place at the surface," he adds to Gizmodo. (The mystery of a puzzling ocean buzz may have finally been solved.)