"Bloop" is a word that people use to describe a sound that scientists heard in the ocean a long time ago. It was a really loud sound that sounded like someone blowing into a microphone or a big balloon popping. The scientists used special tools to listen to the ocean because they wanted to learn more about it.
The sound was so loud that they weren't sure what made it at first. Some people even thought it might be a giant sea monster! But scientists eventually figured out that it was actually just the sound of icebergs cracking and breaking apart in the ocean.
Icebergs are huge blocks of ice that float in the ocean, and sometimes they break apart and make loud noises. Even though the "bloop" happened a long time ago, scientists still talk about it today because it was one of the loudest sounds ever recorded in the ocean.