The Dark Oxygen Research Initiative (DORI) project – Investigating Dark Oxygen Production in the deep sea

Deep-sea benthic organisms consume oxygen as part of a global balance between photosynthesis and respiration, but direct observations of oxygen consumption rates from the abyssal seafloor are scarce relative to its areal extent and the diversity of seafloor habitats. In 2024, Sweetman et al. published research from in-situ benthic incubations from previously unexplored manganese nodule provinces in the eastern equatorial Pacific Ocean, where they found more oxygen was being produced at the abyssal seafloor than was being consumed. In >40 incubations of the seafloor, they found oxygen levels increased in 93% of their enclosed chamber experiments, rising to more than 3-times background levels over 48 hours. DOP occurred exclusively in the presence of manganese oxides. It is presently unclear what the mechanism behind DOP is, but the close link to polymetallic oxides and increase in interest in deep-sea mining necessitates further investigations. Thanks to funding provided by the Nippon Foundation, we are embarking on a multi-year research programme to fully characterize DOP in different deep-sea habitats and developing the Dark Oxygen Research Initiative – the DORI project. This talk will show case the extensive evidence for DOP as well as provide details on the DORI project, which we hope to expand to additional interested partners as the project moves through its various stages.