Scientists studying the area where the Amazon River meets the Atlantic Ocean were in for a surprise. Under the muddy, dark Amazon River water was a large number of undiscovered reefs with colorful sea fans, coral, plants, fish and very big sponges. It was one of the biggest surprises in modern ocean science. Most ocean reefs need sunlight to exist. On their boat that day in 2012, they carried a hand-drawn map that suggested maybe a large set of reefs sat just below them. Brazilian scientist Rodrigo Moura of the Federal University of Rio de Janeiro, brought the map. He had read about the possible reefs in a 1977 research paper. He lowered a dredging machine into the muddy water. Oceanographer Patricia Yager was there too. With others, she leaned over the boat’s edge, waiting to see what Moura would bring up from the bottom. They did not expect much.