Is anoxia a hoax? Evidence for widespread “dark oxygen” production in Earth’s hidden ecosystems.

Emil will talk about the microbial production of molecular oxygen (O2) in the absence of light and its relevance in apparently anoxic natural environments. Together with international collaborators he found evidence for the in-situ production of O2 in diverse subsurface ecosystems across large temporal and spatial scales. This “dark oxygen” production could originate from the microbial dismutation of nitric oxide and/or chlorite, microbial processes that were so far not considered to be important on a global scale. The discovery challenges our current understanding of the evolution, ecology, and biogeochemistry of the subsurface biogeosphere, suggesting aerobic niches in many environments that were thought to be anoxic.