EPSS Colloquium fall-2015

New geochemical proxy data are suggesting a far more dynamic history for initial oxygenation of Earth’s biosphere. Most notably, novel tracers are exposing a middle chapter in Earth history with surprisingly low oxygen contents in the atmosphere, the deep ocean, and the shallow ocean. These challenging conditions were the backdrop for the initial emergence of complex life and set the stage for the rise of animals. This talk will explore this critical interval in Earth’s evolution, the conditions before and after, the transitions, and the advances and debates about these first biological radiations.