The deep-ocean floor is teeming with undiscovered life-forms that help to regulate Earth's climate, a new study finds. Researchers sequenced DNA from deep-sea sediments around the world and found that there is at least three times more life on the seafloor than there is higher up in the ocean. What's more, nearly two-thirds of that life has not been formally identified yet. "It's been known since the 1960s that species diversity is very high in the deep sea, so very high numbers of species," co-author Andrew Gooday [said]. "What was new about this study was that there was a lot of novel diversity at the higher taxonomic level." In other words, there are a lot of unknown evolutionary lineages " like whole families of species " waiting to be discovered. The deep-ocean floor covers more than half of Earth's surface but is home to some of the least-studied ecosystems, according to the study. Previous research analyzed DNA collected through the water column, from above the ocean floor up to the surface, so this latest study sought to complete the picture and give a global view of biodiversity in the ocean by looking at seafloor DNA within deep-sea sediments. The researchers also learned more about the role the deep ocean plays in the so-called biological pump, the process by which ocean organisms such as phytoplankton absorb carbon from the atmosphere near the surface and sink to the deep sea, where the carbon is sequestered in the sediments.