“Mercury is not limited to the upper thousand meters of the ocean, as we once thought,” said Joel Blum, a biogeochemist at the University of Michigan in Ann Arbor. Blum and his colleagues scoped out the mercury content of organisms collected from roughly 6,000–10,000 meters below the ocean surface. That mercury contained chemical clues pointing to fish carcasses from shallower waters as its source, researchers reported in Proceedings of the National Academy of Sciences of the United States of America. The carrion provides a mercury “fast track” to the deep ocean, Blum said.