A team of oceanographers headquartered in Newport recently sent a special microphone deep into the Pacific Ocean's famed Mariana Trench, nearly seven miles below the ocean's surface, and the results were surprising. 

It's noisy down there. 

"In theory it should be one of the quietest places in the ocean," Robert Dziak, a National Oceanic and Atmospheric Administration research oceanographer and chief scientist on the project said of the Challenger Deep region of the Mariana Trench. 

Instead, the small research team based at Oregon State University's Hatfield Marine Science Center, heard a variety of noises and captured what they believe are the first recordings produced from the deepest-known area of the Earth's oceans. 

"We were really surprised at how clear the acoustics are at this place," Dziak said. 

Listen: Read the story, then hear audio recordings at the bottom of the page

After analyzing the audio recordings, researchers identified several earthquakes, the moan of baleen whales, a typhoon and quite a bit of noise from ship traffic 36,000 feet above the specially designed microphone anchored to the trench's seafloor. 

Dziak pitched the $100,000 project two years ago, with the goal of establishing a baseline for ambient noise inside the Mariana Trench. 

Rumbles from the deep: Oregon State teams with researchers to eavesdrop on Mariana Trench 6 Gallery: Rumbles from the deep: Oregon State teams with researchers to eavesdrop on Mariana Trench

"It's fairly well known that man-made noise in the ocean has been increasing for decades," said Dziak, who has worked as a seismologist for NOAA and assistant professor at OSU for more than 20 years. " But it's not really clear yet how this noise affects marine ecosystems and marine animals that use sound to navigate, orient or feed in the ocean." 

Haru Matsumoto, an OSU engineer, helped design the omnidirectional hydrophone to record the ambient noise in the unique environment.  The hydrophone is built to withstand the frigid temperatures of the ocean's deep, but also the crushing pressure.  At sea level, Matsumoto said, humans experience a pressure per square inch of 14.6 - something that is roughly 1,000 times greater at the 36,000-foot depth. 

Crews first launched the hydrophone into the frothy Pacific Ocean near the Federated States of Micronesia in January of 2015 for a test mission. 

Satisfied that it would work, they returned that July aboard the U.S. Coast Guard's cutter Sequoia, based in Guam. 

Deploying the audio device took more than six hours, as engineers had to make sure the instrument survived the ocean's pressure at a descent of roughly 2 meters per second. 

Dziak said the hydrophone was equipped with an anchor, then the mechanism was suspended above the ocean's floor roughly 30 feet. 

The onboard flash drive filled in about 23 days. 

After recovering the device in November, Dziak said researchers immediately went to work, and they were surprised to hear both the level of noise and the quality of the acoustics. 

Whales, in particular, emit an "impressive' amount of noise, he said, considering their maximum depth is tens of thousands of feet higher than the recording device. 

Dziak said he wants to do more recordings, and more projects - for longer periods of time at various sites globally.  Cameras could also be affixed to the device. 

He would like to send a recording device underneath the Arctic's ice cap, in particular, citing the increase of ship traffic in that region. 

There's been minimal research on ocean acoustics at that depth, he said, and it turns out the technology is "really inexpensive."