Just like us, corals breathe in oxygen and eat organic carbon. And just like us, as a byproduct of converting energy and oxygen in the body, corals produce reactive oxygen species (ROS), a family of chemical compounds that are naturally made by cells during cell division, while fighting off pathogens, and performing other functions. We've known this for a while, but we didn't know until recently that healthy corals were producing a specific kind of ROS called superoxide