Lecture on the diversity and function of the Earth’s microbiomes, inclusive of terrestrial and aquatic ecosystems, symbiotic and free living microorganisms with a focus on the microbial underpinnings of the Earth’s biogeochemistry. Repeatable unlimited times. A-F only. Pre: OCN 102 or OCN 201 or BOT 305 or BIOL 305, or BIOL 171 and BIOL 172. (Alt years: Fall) (Cross-listed as OCN 454)