Anyone taking notice in their science lessons would know that sunlight was needed for green plants and some organisms to create oxygen through photosynthesis. It may have been in a multiple choice question or require a longer answer, but it was a black mark if you missed the sunlight bit. Now it seems we may have been in the dark all along. Scientists have reportedly discovered that oxygen is produced by “potato-shaped metallic nodules” in pitch blackness over 13,000 feet (4,000 meters) beneath the ocean’s surface. In the findings, published in the journal Nature Geoscience, scientists said they found many of these nodules carried an electric charge that split seawater into hydrogen and oxygen through “seawater electrolysis” in a seabed between Mexico and Hawaii. Team leader Professor Andrew Sweetman explained: “We now know that there is oxygen produced in the deep sea, where there is no light. I think we therefore need to revisit questions like: where could aerobic life have begun?”