Welcome to the Fischer Group.
The sedimentary rock record reveals that life has been a conspicuous part of our planet for at least the last 3.5 billion years, and thus, the history of the Earth is inseparable from the history of life on Earth. Broadly, we work to understand the coevolution of life and Earth surface environments. Our major focus concerns questions and contradictions in understanding of the timing and evolution of oxygenic photosynthesis and the subsequent rise of atmospheric oxygen.
The rise of atmospheric oxygen circa 2.4 billion years ago is one of the most marked environmental changes in Earth history, and this transition ultimately 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 a source of electrons. Molecular oxygen became widely available for use in anabolic and catabolic metabolisms, forming a rich cascade of evolutionary potential and consequence. 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.