Podcast:Short Wave Published On: Mon Jul 28 2025 Description: The twilight zone of the ocean is a mysterious place. At 200-1000 meters below the surface, it's a tough place to study. That's why, during World War II, people reading sonograms from this zone were perplexed when it looked as if the ocean floor was moving up. Every day. And then back down again before dawn. In this latest installment of Sea Camp, we explore what this historical mystery has to do with the Earth's ability to cycle and store carbon in the ocean's watery depths.SIGN UP FOR OUR SEA CAMP NEWSLETTER! WE WORKED SO HARD ON IT!Interested in more ocean mysteries? Let us know at shortwave@npr.org.Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.To manage podcast ad preferences, review the links below:See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy