The reason I questioned the literal battery theory / electrolysis is based on this quote from the BBC article The scientists worked out that the metal nodules are able to make oxygen precisely because they act like batteries. I have since found the original research paper (i linked it elsewhere in this post) which suggests the authors did not actually say that and aren’t sure of the exact mechanism. Your ‘voltage potential grabbing polar ends’ is not one on the known methods of splitting water into oxygen and hydrogen (see wikipedia, which all require electricity, light, radiation or extreme heat. None of which seem to apply here, and the paper also does not mention hydrogen being produced. So maybe there isn’t water being split here by these nodules
Still dead, and not on iOS App Store anymore