Nine hundred hours of deep-sea video footage has revealed a lot about how little we understand the abyssal ocean. Researchers scrutinizing the footage, taken around Pacific islands such as Hawai\u2018i, have concluded that they only recognize roughly a fifth of the creatures caught on the recordings.<\/p>\n
The research<\/a>, presented at a scientific meeting<\/a> in San Diego, California\u00a0this week, gives a clear sense of just how mysterious the deep sea really is. \u201cThere\u2019s a lot left to discover,\u201d says biologist Randi Rotjan of Boston University in Massachusetts, who coauthored the work.<\/p>\n It\u2019s an often-quoted (and very true) statement that we have better maps of the moon than we do of the ocean floor. But quantifying just how mysterious the deep sea is is tricky. Most previous studies, says Rotjan, have focused on discovering new species or surveying smaller areas, and it\u2019s hard to compile broad statistics on deep-sea life from lots of little studies done with different methodologies.<\/p>\n The new report is based on data from the CAPSTONE project, an epic campaign led by the US National Oceanic and Atmospheric Administration (NOAA) to study the seafloor around western and central Pacific islands. From 2015 to 2017 the scientists mapped 597,230 square kilometers, documenting an area bigger than California, though still less than half a percent of the total Pacific Ocean. Robotic divers visited habitats ranging from near-deserted abyssal plains to lush hydrothermal vents and caught more than 347,000 deep-sea creatures on camera\u2014everything from tiny worms to sharks the size of pickup trucks.<\/p>\n A team of experts concluded that fewer than 20 percent of the creatures spotted could be identified at the species level. Sometimes that was because the photos were too grainy or the species too small to identify without a microscope, says Rotjan. But the majority were simply unknown.<\/p>\n Kasey Cantwell, a physical scientist with NOAA in Maryland and a member of the project team, says this is the first time anyone has tried to use such a massive data set to quantify how many unknown species there are in the deep sea. The results help pin down estimates of deep-sea biodiversity and abundance. Down the road, the data could help target especially diverse or unique spots for future exploration or conservation efforts.<\/p>\n