Similar to the spikes in methane already observed. Of course scientists are saying they need to eliminate any geochemical processes before even saying “life”, sotto voce.
Link: https://www.scientificamerican.com/article/nasas-curiosity-rover-finds-unexplained-oxygen-on-mars/?utm_source=newsletter&utm_medium=email&utm_campaign=daily-digest&utm_content=link&utm_term=2019-11-20_featured-this-week&spMailingID=61386192&spUserID=NTM5N