IGPP Seminar Series

Co-evolution of life and Earth surface environments just prior to the rise of oxygen

by Woodward Fischer
Caltech

Abstract

Co-evolution of life and Earth surface environments just prior to the rise of oxygen One of the most marked environmental changes in Earth history, the rise of atmospheric oxygen (~ 2.4 Ga), stems from a major biological innovation.  The evolution of oxygenic photosynthesis conferred the ability to use water as a photosynthetic substrate (earlier photosynthesis was anoxygenic and required reduced iron, sulfur, or hydrogen).  Primary productivity was no longer limited by source of electrons.  Molecular oxygen became widely available for use in anabolic and catabolic metabolisms.  This innovation profoundly altered biogeochemical cycles, led to the buildup of oxidants in the atmosphere and oceans, and ultimately paved the way for modern surface environments bathed in free oxygen.  In this talk, I will present some of our recent research aimed at understanding both the Archean baseline and the co-evolution of life and the environment through this transition, from the perspective of observations made in ancient sedimentary rocks.
Tuesday, 15 February 2011
7124 Math Sciences
Refreshments at 3:45 PM
Lecture at 4:00 PM