Groups College of Sciences News Room Research Horizons Status Workflow Status: Published Created By: Ben Brumfield Created: 08/22/2018 Modified By: Modified: 08/22/2018 Categories Research , Chemistry and Chemical Engineering , Engineering , Environment , Life Sciences and Biology Keywords Proterozoic Eon , biogeochemistry , nitrous oxide , N2O , laughing gas , ferrous iron , iron cycle , nitrogen cycle , nitrogen breathing microbes