Image provided by: University of Oregon Libraries; Eugene, OR
About The daily Astorian. (Astoria, Or.) 1961-current | View Entire Issue (Dec. 7, 2019)
A3 THE ASTORIAN • SATURDAY, DECEMBER 7, 2019 Robot records sounds of underwater life along Pacifi c Coast can only sample at individual locations and depths. Gliders with hydrophones have not been For 18 days, an underwater robot dived used for extensive noise monitoring before, and surfaced and dived and surfaced — largely because the vehicles’ rudders often some 402 times in all — listening to the interrupt recordings. Haxel and other sci- ocean’s depths as it traveled hundreds of entists managed to fi lter rudder noise from miles along the continental shelf off the their audio using computer algorithms. Washington state and Oregon coastline. “I have not seen anybody do an ambient The torpedo-shaped robot, called a noise study with gliders like this before,” glider, captured the percussive roar of a said Elizabeth Küsel, a senior scientist with research ship’s air gun, which reverberated JASCO Applied Sciences, who has worked like a muffl ed bass drum. It listened to what with gliders for about a decade and was not sounded like the churn of a wobbly wash- involved in this research. “Their work is ing machine, which indicated the presence very valuable.” of a ship passing nearby. The 120-pound Research scientists launched the glider robot even caught the delightful, baritone on July 20, 2012, off Grays Harbor, Wash- whining of humpback whales. ington. It arrived two and a half weeks later For years, scientists have been working near Brookings, some 285 miles away. to untangle the mysteries of ocean sound. The robot traveled, on average, less than Noise travels much farther underwater than 1 mph. Its median dive depth was more it does in air. than 2,050 feet below the ocean’s surface. “Sound is to marine animals what light Scientists recorded throughout its jour- is to people on land,” said Joe Haxel, an ney, capturing audio of at least 11 encoun- assistant professor at Oregon State Uni- ters with Pacifi c white-sided dolphins, versity in marine resources studies. It is three brushes with humpback whales and the medium through which these creatures several other creatures scientists could not hear, locate themselves and communicate. identify. Just how noisy is the The robot also cap- sea? Are humans — with tured passing vessels and freight ships and ocean the powerful air gun of a ‘THIS IS A NEW drilling and sonar testing National Science Foun- WAY TO MAKE — making it louder? dation ship conducting “We know so little research off the MEASUREMENTS seismic about the overall noise in coast. the ocean and how that “It’s basically an THAT INFORM affects things — the crit- explosion,” Haxel said US ABOUT ters that live there,” said of the air gun’s blasts. Chris Meinig, the direc- “Every 20 or 30 sec- WHAT’S GOING tor of engineering for onds you’re getting a ON OUT THERE.’ large rumble in the water the National Oceanic and Atmospheric Adminis- column.” Joe Haxel | assistant professor tration’s Pacifi c Marine Oil and gas compa- at Oregon State University in Environmental Labora- nies also use seismic air marine resources studies tory in Seattle. guns to research possible A new research paper, deposits. Their use is con- authored by both Haxel troversial because these and Meinig and published last month in the blasts can harm nearby animals. peer-reviewed science journal PLOS ONE, At times, the research air gun was loud chronicles the glider’s travels and explains enough to register “above the sensitivity how this technology allows scientists to lis- threshold we could measure,” Haxel said, ten to the sea and explore its murky depths. though the scientists were using a particu- “This is a new way to make measure- larly sensitive hydrophone. ments that inform us about what’s going on Still, on the whole, the scientists found out there,” Haxel said. that ocean noise off the coast had remained Most ocean gliders operate without pro- similar to measurements from the 1990s pellers or any propulsion system at all. taken from fi xed moorings. Instead, they carve through the water Large vessels did not have as signifi - because of their wings, which angle cant an impact on overall noise levels as against the saltwater as the robot adjusts its Haxel had expected. The scientists com- buoyancy. pared tracking data from ships and found “We use the wings to adjust the attitude little correlation between overall noise and and the fl ight path,” Meinig said. ship presence. Mechanical rudders are often equipped “That was an eye-opener for me. I used to help keep the machine on course. Bat- to think ships are so loud,” Haxel said. But teries inside the tubular machine can move along the continental shelf, which features and adjust its ballast. an uneven sea fl oor, an energetic, wavy When gliders surface, they can commu- ocean surface and unique physical prop- nicate with satellites, share data and get erties in the water column, sound emanat- instructions from their handlers. Then, they ing from ships seemed to get “trapped” and dip back down to a programmed depth, have “limited range,” he said. before beginning to climb through the These results can’t be extrapolated to water again. other locations. Scientists use gliders to gather ocean “Your sound velocity profi le is going to temperatures, information about salinity look a lot different in Puget Sound,” Haxel and myriad other measures. said. Seagliders were invented at the Univer- Gliders have been used to map the sound sity of Washington. These robots have been of erupting underwater volcanoes, help searching the ocean for clues to science’s with National Oceanic and Atmospheric mysteries for about 15 years, Meinig said. Administration hurricane forecasts and But the technology continues to develop. also to listen to deep-diving baleen whales. Because gliders do not have propellers, They’ve fl own through the Blob-like the quiet machines rarely disrupt normally marine heat wave roiling the Pacifi c Ocean, skittish animals, Haxel said. in the Bering Sea near Alaska and beneath “They’re kind of sneaky,” he said. ice at both polar continents, Meinig said. Hydrophones, which are essentially “There’s probably more simple robots underwater microphones, have allowed sci- in the ocean than anywhere else,” Meinig entists to gather acoustic data from gliders said. And with gliders, “We’re doing ever for many years. increasing and challenging things.” But studies of ambient ocean noise have Each fl ight, these robots reach a bit fur- typically relied on fi xed moorings, which ther into the unknown. By EVAN BUSH Seattle Times Oregon State University Oregon State University acoustic engineer Haru Matsumoto dives behind a glider being tested in Kona, Hawaii. After testing, scientists sent the glider on an 18-day trip along the Washington state and Oregon coast to listen to ocean noise and record what it heard. H a p p y H o l i d a y s Fr o m Seaside Outlets Kiwanis Christmas Trees E! FRE Gift Wrapping At Scout Northwest Trading Company in the Mall Donations welcome to benefit local charities Happy Holidays from Great Gift Ideas ! Buy 2 Crowlers get the 3rd 1/2off! Offer expires12/31/19 Limit one couple per visit Visit us in the Mini Mart! 2264 Marine Drive (in Astoria Mini Mart East - Mill Pond area) www.TheGrowlerGuys.com | www.AstoriaMiniMart.com Holida Growle y r Gift Pack $ 2 99 6 TheGrowlerGuysAstoria
