Via Kottke, we learn that after over a decade of readings that suggested significant amounts of oxygen were being produced on the seafloor, dismissed as an error since no photosynthesis can occur in the region of the deep where no sunlight penetrates, researchers have now concluded that the “dark oxygen” is real and likely produced by polymetalic nodules strewn across the ocean floor in the Clarion-Clipperton region—see also below. The result of millions of years of accretion of elements dissolved in seawater, these lumps, composed of manganese, copper, cobalt and lithium, working in concert are natural batteries, cause electrolysis and split seawater into its component hydrogen and oxygen with its voltage. Maybe abiotic pathways for oxygen resources could support life elsewhere. It is precisely this property that has attracted mining companies with proposals to harvest the nodules for raw material for battery manufacture, with many in the scientific community calling for a moratorium on development for fear it would destroy a potential ecosystem that we know nothing about.