Researchers say the polymetallic nodules that mining companies hope to harvest from the deep-ocean seafloor may be a source of oxygen for the animals, plants and bacteria that live there. The work about the discovery of this “dark oxygen” was published in the journal Nature Geoscience. “This study is a really good example of how limited our knowledge of the deep ocean currently is, and how much more we still stand to benefit with further scientific research,” said Diva Amon, a marine biologist from Trinidad and a post-doctoral researcher at the University of California, Santa Barbara’s Benioff…