A new study reverses the idea that the bulk of life in the ocean is fueled by photosynthesis via sunshine, revealing that many ocean microbes in fact get their energy from hydrogen and carbon monoxide. It has always been a mystery as to how microbes growing in deepest parts of the sea survive, with no sunlight. A new study shows that a distinct process called chemosynthesis — growth using inorganic compounds — fuels microbes in these darkest depths.