Spanning 1.7 million square miles of ocean from Hawaii to Mexico, a hidden underwater world teems with life. More than 5,500 deep-sea species reside in the area of the Pacific known as the Clarion Clipperton Zone, and roughly 90 percent of them have yet to be described by science, according to a new study.

“Everything in the [deep sea] is extremely cold and obviously completely dark,” says Adrian Glover, a co-author on the study and scientist at the Natural History Museum of London, which led the research. “The amount of food is very low. Yet somehow—you know, the cheesy Jurassic Park line—life finds a way to survive down there.”

To create a comprehensive inventory of all the species living