This is the largest patch of manganese nodules ever found in the Atlantic, Devey said.
Manganese nodulePin It Manganese nodules discovered on the deep seafloor in January 2015.
Manganese nodules have been found in every ocean, but are most common in the Pacific Ocean. The metal lumps, which most often look like pancakes, are formed of layer upon layer of metal ore that slowly crystallizes around a core. The core may be a fossil, a rock or fragment of another nodule.
"These were very, very circular, which is strange," Devey said. "They usually look like cow flops."
Scientists think the nodules grow very slowly, padding themselves by less than an inch (1 centimeter) in a million years. The largest nodules found by the R/V Sonne scientists could be as old as 10 million years, Devey said. Because the spheres are so old, they could provide a record of past climate change, he added.