Jeremy Potter/Courtesy of NOAA
Katrin Iken and Elisabeth Calvert prepare to dive into 30-degree water in the Arctic ocean. Shawn Harper holds the safety line.
Researchers call it the Hidden Ocean. It's the deepest part of the Arctic Ocean, north of Alaska. More than a mile deep, it is locked in ice most of the year. Now, an international team of more than 40 scientists is probing the Hidden Ocean, working from a U.S. Coast Guard icebreaker. NPR's Richard Harris recently spent some time with the expedition and sent back this audio postcard from the sea ice.